Communications – Sumeeth Nagaraja, Tao Luo, Makesh Pravin JOHN WILSON, Qualcomm Inc
Abstract for “Uplink resources to beam recovery”
These are methods, systems, devices, and protocols for wireless communication. Beam recovery messages can be transmitted using uplink resources. A configuration for resources can be received from a base station to enable a user equipment (UE), which is communicating in a beamformed transmissions system, to receive resources. These resources could then be used for beam signaling. A beam failure may be identified by the UE and transmitted to the base station. The beam recovery message can be sent according to the base station’s configuration. In this case, the beam message will be transmitted using beam recovery resources. The configuration may also be transmitted to the UE by radio resource control (RRC), or via a broadcast of system information from the base station.
Background for “Uplink resources to beam recovery”
“The following applies generally to wireless communication and, more specifically, to uplink resources to beam recovery.”
Wireless communications systems are used to transmit various communication types, including voice, video, packet data and messaging. These systems can support communication with multiple users by sharing system resources (e.g. time, frequency and power). Multiple-access systems can include code division multiple acces (CDMA), time division multiple accessibility (TDMA), frequency division multiple Access (FDMA), and orthogonal frequency division multiple access OFDMA systems. These systems may also be used to support communication with multiple users by sharing system resources (e.g., time, frequency, and power). Wireless multiple-access communication systems may have a number base stations or access nodes that support communication for multiple communication devices. These communication devices may also be known as user equipment (UE).
“Some wireless communication systems, such as NR systems, may operate in frequency bands that allow beamformed transmissions between wireless device. Transmissions in millimeter-wave (mmW), for example, may have higher signal attenuation (e.g. path loss) than transmissions in non mmW frequency ranges. Signal processing techniques like beamforming can be used to combine energy coherently, and overcome path losses in these systems. Sometimes, misalignment can occur between active beams from two wireless devices. A UE can detect a beam misalignment or beam failure and attempt to connect with uplink resources. However, some of the uplink resources used for beam recovery may have limited throughput, high latency or both. It may therefore be desirable to improve uplink resource allocation techniques for beam recovery.
“The techniques described herein relate to improved methods and systems, devices, and apparatuses that support beam recovery uplink resources. The described techniques allow for the configuration of dedicated resources to enable one or more UEs transmit a beam recovery request from a base station. These resources can be configured dynamically, semi-statically by the base station and communicated with one or more UEs. Using the techniques described herein, a UE can determine a beam failure (e.g. due to misalignment) on one or more active beams and then use the configured resources for the beam recovery message. One or more downlink beams, which may each have an associated reference signal, may be linked with uplink resources that the UE can use to transmit the beam recovery message. The beam recovery message could contain measurements or other information that may be helpful to the base station in reconnecting with UE.
“A method for wireless communication” is described. This may involve receiving a configuration to beam recovery resources, identifying a beam loss of one or more active beams that are used to communicate with a base stations, and then transmitting a beam recovery message using the beam resources determined to be at least partially responsible for the beam failure to the base station.
“A wireless communication apparatus is described. The apparatus can include means to receive a configuration for beam recover resources, means to identify a beam failure in one or more active beams that are used to communicate with a base stations, and means to transmit, according to the received configuration to the base station, a beam message using the beam recovery resource based at most in part on the identified beam loss.
“Another apparatus is described for wireless communication. The apparatus can include a processor and memory for electronic communication with it. Instructions may be stored in the memory. The instructions can be used to instruct the processor to identify a beam loss in one or more active beams that are being used to communicate with a base stations and to transmit, according the received configuration, a beam restoration message to the base station using beam recovery resources that are at least partially based on the identified beam failure.
A non-transitory computer-readable medium for wireless communication” is described. Instructions may be included in the non-transitory computer readable medium that allow a processor to obtain a configuration for beam recover resources, identify an active beam failure, and then transmit, according the received configuration, to the base station a beam recovery message using the beam resources determined at least partially from the identified beam failure.
“Some of the non-transitory computer readable media and methods described above may also include features, means or instructions for receiving a message back from the base station. The message includes an indication of a set reference signals for beam refinement. The beam recovery message is transmitted to the base station using some of the above-described methods, apparatuses, and non-transitory computers-readable media.
“In some cases of the non-transitory computer readable medium and the apparatus described above, receiving configurations for beam recovery resources includes: receiving the configuration either as part radio resource control (RRC), signaling from base station, or as part a system information broadcast from base station. The non-transitory computer readable medium, apparatus and method described above may also include features, means or instructions that enable the reception of an indication that allows the beam to recover resources to be used for transmission of the beam message. In this case, transmitting the beam message may be at least partially based on the indication.
“Some examples, of the non-transitory computer readable medium and method described above, may also include features, means or instructions for receiving an indicator that disables use of beam recovery resources for transmission of the beam message. In this case, transmitting the beam message may be at least partially based on the indication. The configuration may include a UE-specific configuration of the beam recovery resources. The configuration is used in some of the above-described methods, apparatuses, and non-transitory computer readable media. It includes an indication of a plurality beams to transmit the beam-recovery message. This indication is based at most in part on a signal?to-noise ratio, (SNR), associated with the UE. In other words, transmitting beam recovery messages involves: using at least one beam from the plurality.
“In some cases of the non-transitory computer readable medium, apparatus and method described above, the configuration includes an indication of a system number (SFN), corresponding beam recovery resource, a subframeindex (SFI) which corresponds to beam recovery resource, a periodicity that corresponds to beam recovery resources, one (or more) resource elements (REs) or a combination thereof.”
“In some cases of the non-transitory computer readable medium and method described above, the beam recover resources occupy a first area of resources that can be different from the second region of resources used for transmission of random access messages. The configuration may include an indication of a mapping between the downlink beam from base station and beam recovery resources in some of the above-described methods, apparatuses, and non-transitory computers-readable media.
“Some examples of the non-transitory computer readable medium and method described above may also include processes, features or instructions for transmitting, depending on the received configuration, an order (SR) to base station using beam recovery resources. The non-transitory computer readable medium and the apparatus described may also include the following: processes, features, methods, or instructions for measuring a set or reference signals. These reference signals are associated with one or more active beams. In this case, the beam recovery message includes a measurement report that is at least partially based on the measured signals.
“In some cases of the method, apparatus and non-transitory computers-readable medium described above, a measurement report includes a reference signals received power (RSRP), quality (RSRQ), channel quality indicator(CQI), precoding matrix indicator, PMI, or a combination thereof. The set of reference signals may include a synchronization, a mobility, a channel information reference signal (CSIRS) or a combination of both.
“Some of the methods, apparatus, and nontransitory computer-readable media described above may also include processes, features or instructions for determining a mobile condition associated with UE. The mobility condition of UE comprises a direction of UE relative to base station, an orientation or distance from base station or a combination thereof. In the beam recovery message, an indication of the mobility conditions is included. The method, apparatus and non-transitory computer readable medium may also include features, means or instructions for identifying antenna information corresponding one or more antennas located at the UE. In these cases, the beam recovery message contains an indication of the antenna information.
“In some cases of the non-transitory computer readable medium and method described above, the antenna array data comprises a number antenna arrays located at UE. The method, apparatus and non-transitory computers-readable medium may also include features, means or instructions for determining the identity of a downlink beacon from the base station. In these cases, the beam recovery message includes an indication of the identity.
“A method for wireless communication” is described. This may involve communicating with one or several UEs using one, or more active beams and transmitting a configuration to beam recovery resources. The beam recovery messages can be received on the beam resources.
“A wireless communication apparatus is described. The apparatus can include means to communicate with one or several UEs using one, or more active beams. It also includes means for transmitting a configuration of beam recovery resources and means for receiving one, more or all of the beam recovery messages on beam recovery resources. These messages indicate a beam failure of at most one of the one, or more, active beams.
“Another apparatus is described for wireless communication. The apparatus can include a processor and memory for electronic communication with it. Instructions may be stored in the memory. Instructions may be used to instruct the processor to communicate one or several UEs using one, more or all active beams, to transmit a configuration to beam recovery resources and to receive one or multiple beam recovery messages on beam recovery resources. These messages indicate a beam failure of at most one of the active beams.
“A non-transitory computer-readable medium for wireless communication” is described. Instructions may be included that allow a processor to communicate using one or multiple active beams with one or other UEs and transmit a configuration to beam recovery resources. The processor can also receive one or several beam recovery messages on beam recovery resources. These messages indicate a beam failure of at most one of the active beams.
“Some examples of the non-transitory computer readable medium and method described above may also include features, means or instructions for sending a message to a UE to respond to one or more beam-recovery messages. The message will contain an indication of a set reference signals for beam refinement. The non-transitory computer readable medium and the method described may also include features, means or instructions to receive the one or more beam-recovery messages. This includes receiving a measurement report. The non-transitory computer readable medium, apparatus and method described above may also include features, means or instructions to determine a transmit beam direction using at least part of the measurement report. The method, apparatus and non-transitory computers-readable medium may also include features, means or instructions for transmitting the message from the UE using the determined transmit beacon direction.
“Some of the non-transitory computer readable media, apparatus and method described above may also include processes, features or means for measuring uplink signals over one or more active beams. The non-transitory computer readable medium and apparatus described above may also include features, means or instructions for determining a transmit be direction based at minimum in part on measurements of uplink signals. In this case, the transmit beam direction may be used to transmit the message to the UE. Receiving the one or several beam recovery messages is one way to receive the apparatus, method and non-transitory information-readable medium.
“Some examples of the non-transitory computer readable medium and method described above include transmitting the configuration to the beam recovery resources as part RRC signaling, or in a system information broadcast. The non-transitory computerreadable medium, apparatus and method described above could also include features, means or instructions for transmitting an indicator that enables the beam recovery resources to be used for one or more beam message recovery messages. Receiving the one or several beam recovery messages may be based at most in part on this indication.
“Some of the non-transitory computer readable media, apparatus and methods described above may also include features, means or instructions for transmitting an indicator that disables the use beam recovery resources for one or more of the one or two beam recovery messages. Receiving the one or several beam recovery messages may be based at most in part on the indication. In some cases, the apparatus and non-transitory medium described above allow for identification of a traffic level that is associated with a subset or more UEs. The configuration for beam recovery resources is transmitted to this subset using the traffic level.
“Some examples of the non-transitory computer readable medium and method described above may also include features, means or instructions for identifying an SNR associating with a UE. In such cases, the configuration includes a UE-specific configuration beam recovery resources based at minimum in part on the identified SNR. The configuration may include an indication that there are multiple beams for each one or more of the beam recovery messages.
“Some examples of the non-transitory computer readable medium and method described above may also include features, means or instructions for identifying a payment load associated with uplink transmissions from one or more UEs. The configuration includes an indication of additional beam recover resources that have been allocated to the one or several beam recovery messages based at most in part on the identified payload. The beam recovery resources can be associated with one region of resources, which may be different than the second region that is used for transmission of random access messages.
“Some examples of the non-transitory computer readable medium, apparatus and method described above may also include processes, features or means for identifying one of the reference signals associated with a series of downlink beams. The method, apparatus and non-transitory computers-readable medium may also include features, means or instructions to identify a mapping between beam recovery resources, set of downlink beams, and the configuration, which is based at minimum in part on one or more reference signal.
“Some wireless communication systems can operate in frequency bands that allow beamformed transmissions between wireless device. Communications in the mmW frequency band may experience higher signal attenuation (e.g. path loss) than communications in other frequencies. Signal processing techniques like beamforming can be used to combine energy coherently, and overcome path losses in these systems. Wireless devices such as a base station and UE may be able communicate with each other over active beams. These beams may correspond to the transmit beam used by the transmitting device and the receive beam at the receiving device (e.g., comprising an active beam pair). Sometimes, the active beam pair(s), such as a beam switch failure, signal blockage, may be misaligned so that the UE or base station are unable to communicate over the obstructed active pair(s). The beam failure may be detected by a UE, for example, by monitoring a subset or reference signals on active beams that are used to communicate with base station.
The UE may require resources to reconnect with the serving cells. These may include time, frequency and/or a beam. The UE may use certain uplink resources to connect with the cell in a multi-beam system. A UE might default to using SR or random access channel resources (RACH) to transmit a beam recovery request. These resources can have a limited throughput or high latency, due to contention-based resources, or because they are available with a low periodicity. Some systems support the configuration of one or multiple sets of dedicated resources to a UE (or multiple) in order to transmit beam recovery requests. This may allow for faster, stronger, and more efficient recovery.
“The beam recovery message transmission techniques described herein can be achieved using the dedicated resources that are available. A UE may, for example, receive a configuration from a base station for uplink resources. The uplink resources could be used for beam recovery signaling. A beam failure may be identified by the UE, which may include path loss or interference on one or more active beams. The UE can then transmit a beam recovery message (to the base station) to indicate this. The beam recovery message can be sent according to the base station’s configuration. In this case, the beam message will be transmitted using the designated beam recovery resources. The configuration may be transmitted to the UE via RRC or system information broadcasts from the base station. The base station may also indicate whether the beam resources are being used. For example, lower layer signaling may be used to enable or disable the beam recovery resource. In this case, the UE can transmit the beam message on different resources based on whether or not the beam resources have been disabled. The UE can monitor the base station for a response to the beam request message.
“Aspects are first described in the context a wireless communication system. Additional examples include a uplink resource grid, and a process flow to transmit a beam recovery message. The disclosure is further illustrated and described using apparatus diagrams, system diagrams and flowcharts that pertain to beam recovery uplink resources.
“FIG. “FIG. 1 illustrates a wireless communication system 100 according to various aspects of this disclosure. Wireless communications system 100 comprises base stations 105, core networks 130, and UEs 115. The wireless communications system 100 could be LTE, LTE Advanced (LTE A) network, or a NR network. Wireless communications system 100 can be used to support ultra-reliable communications (i.e. mission critical), enhanced broadband communications, and communications that are low-cost and complex. Wireless communications system 100 could support efficient uplink resource utilization for beam recovery.
“Base stations 105 can wirelessly communicate with UEs 115 using one or more base station antennas. Each base station 105 can provide coverage in a specific geographic area 110. The communication links 125 in wireless communications system 100 can include uplink transmissions between a UE 115 and a base stations 105 or downlink transmissions between a basestation 105 and a UE 115. Multiplexing control information and data on an uplink channel, or downlink, may be possible according to different techniques. Multiplexing control information and data on a downlink channel may be possible using various techniques. For example, time division multiplexing techniques (TDM), frequency division multiplexing techniques (FDM), or hybrid TDM/FDM techniques. ”
The UE 115 can be distributed throughout the wireless communications network 100. Each UE 115 could be mobile or stationary. A UE 115 can also be called a mobile station or subscriber station. Each UE 115 could be stationary or mobile. A UE 115 could also refer to a cellular phone or a personal digital assistant (PDA), a wireless device, a wireless communication device and a handheld computer, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a client, a mobile client, or some other suitable terminology.
“The core network 130 could provide user authentication, access authorization and tracking, Internet Protocol connectivity, as well as other access, routing or mobility functions. Subcomponents, such as a basestation 105, may be included in at least some network devices. This could include an access network entity (ANC), which may be an example access node controller. Each access network entity may communicate with a number of UEs 115 through a number of other access network transmission entities, each of which may be an example of a smart radio head, or a transmission/reception point (TRP). In some configurations, different functions of an access network entity (or base station 105) may be spread across multiple network devices (e.g. radio heads and access controllers) or combined into one network device (e.g. a base station 105)
“Wireless communication system 100 may operate at ultra-high frequencies (UHF), using frequency bands ranging from 700 MHz up to 2600MHz (2.6GHz), though in certain cases wireless local area networks may use frequencies up to 4GHz. The decimeter band may also be called this region, as its wavelengths are approximately one to one meter long. UHF waves can propagate mostly by line-of-sight, but may be blocked by buildings or other environmental features. The waves can penetrate walls enough to provide service to UEs 115 indoors. Transmission of UHF waves has a shorter range and smaller antennas than transmission using the higher frequencies (and longer waves), portion of the spectrum. Wireless communications system 100 can also use extremely high frequency (EHF), portions of the spectrum in certain cases (e.g. 30 GHz to 300GHz). This area may also be called the millimeter spectrum, as it has wavelengths that range from one millimeter up to one centimeter long. EHF antennas can be smaller and less spaced than UHF antennas. This may allow for the use of an antenna array within a UE 115 in certain cases (e.g. for directional beamforming). EHF transmissions can be subject to greater atmospheric attenuation, and may have a shorter range than UHF transmissions.
“Wireless communications 100 may support mmW communications between base stations 105 and UEs 115. Multiple antennas may be used to beamform devices operating in the mmW and EHF bands. A base station 105 can use multiple antennas or arrays to perform beamforming operations in order to transmit directional information with a UE 115. Beamforming, also known as spatial filtering and directional transmission, is a signal processing technique that can be used at a transmitter (e.g. A base station 105, to steer and shape an antenna beam in the direction desired by a target receiver (e.g. a UE 115. Combining elements in an antenna array so that transmitted signals from certain angles experience constructive interference and others experience destructive interference may help achieve this effect.
Multi-input multiple output (MIMO) wireless systems utilize a transmission scheme that links a transmitter (e.g. A base station 105, and a receiver (e.g. a UE 115, where both receiver and transmitter are equipped with multiple antennas. Beamforming may be used in some parts of wireless communications system 100. Base station 105 might have an antenna array that has a number rows and columns of antenna ports. This antenna array may be used by base station 105 for beamforming its communication with UE 115. Multiple transmissions of signals may occur in different directions. Each transmission could be be beamformed differently. A mmW receiver, such as a UE 115, may attempt multiple beams (e.g. antenna subarrays), while simultaneously receiving the synchronization signal.
“In certain cases, antennas from a base station 105 and UE 115 might be placed within one or more antenna arrays (e.g. panels), which could support beamforming or MIMO operation. An antenna tower, or an antenna assembly that houses multiple antenna arrays or base station antennas, may contain one or more of these antennas. Antennas and antenna arrays that are associated with base station 105 can be found in different geographic locations. Multiple antennas or arrays may be used by a base station 105 to perform beamforming operations in order to transmit directional information with a UE 115.
“In certain cases, wireless communications system 100 could be a packet-based network operating according to a layer protocol stack. The user plane may have IP-based communications at the bearer layer or Packet Data Consvergence Protocol (PDCP). In some cases, a radio link control layer (RLC), may perform packet segmentation and reassembly in order to communicate over logical channel. Medium access control (MAC), a layer that handles priority handling and multiplexing logical channels into transport channel, may be used. To improve link efficiency, the MAC layer can also use hybrid automated repeat request (HARD). The RRC protocol layer in the control plane may establish, configure, and maintain an RRC connection between a UE 115, a network device or core network 130 that supports radio bearers for user-plan data. Transport channels can be mapped to physical channels at the physical layer (PHY).
A resource element can be composed of one subcarrier and one symbol period (e.g., 15 kHz frequency range). A resource block can contain 12 consecutive subcarriers within the frequency domain. For a normal cyclic prefix (OFDM) symbol in each orthogonal frequency Division Multiplexed (OFDM), 7 consecutive OFDM symbols in time domain (1 slot), which is 84 resource elements. Modulation scheme (the combination of symbols that can be selected in each symbol period) may affect the number of bits each resource element can carry. The data rate of UE 115 may increase if it receives more resource blocks and has a higher modulation scheme.
“Wireless communications systems 100 may allow operation on multiple carriers or cells, which is known as carrier aggregation (CA), or multi-carrier operation. An operator may also be called a component carrier (CC), layer, channel, or channel. The terms “carrier”,?? ?component carrier,? ?cell,? ?cell?,? These terms may be interchangeable. A UE 115 can be configured with multiple downlink CCs, and one or more of the uplink CCs to enable carrier aggregation. Carrier aggregation can be used with either frequency division duplexed or time division duplexed component carriers.
“Wireless communications system 100 may use enhanced component carriers (eCCs) in certain cases. An eCC can be distinguished by one or more of the following features: a wider bandwidth, shorter symbol durations, shorter TTIs and modified control channel configurations. An eCC can be associated with a carrier aggregation setup or a dual connectivity configuration. This is when multiple serving cells have a suboptimal backhaul link. An eCC can also be used in unlicensed or shared spectrum, where more than one operator has access to the spectrum. A eCC with a large bandwidth can include one or more segments. UEs 115 may also be able to use the spectrum in unlicensed or shared spectrum.
An NR shared spectrum system may use a shared radio frequency band. An NR shared spectrum can use any combination of licensed, unlicensed, or shared spectrums. Flexibility in eCC symbol length and subcarrier spacing may permit the use of eCC across multiple frequencies. Some examples show that NR shared spectrum can increase spectrum utilization and spectral efficacy, particularly through dynamic vertical (e.g. across frequency) or horizontal (e.g. across time) sharing resources.
Wireless communications system 100 can use both licensed and unlicensed radio frequency bands in certain cases. Wireless communications system 100, for example, may use LTE License Assisted Access or LTE Unlicensed radio access technology (LTE U), or NR technology in unlicensed bands such as the 5GHz Industrial, Scientific and Medical (ISM). Wireless devices, such as base stations (105) and UEs (115), may use listen-before-talk procedures to ensure that the channel is clear before they transmit data. Sometimes, operations in unlicensed band may be based upon a CA configuration along with CCs operating within a licensed spectrum. Unlicensed spectrum operations may include uplink transmissions or downlink transmissions. Duplexing in unlicensed frequency can be done using FDD, TDD, or a combination of both.
“Beam recovery messages can be transmitted in wireless communications system 100 using resources (e.g. uplink resources). A UE 115 may, for example, receive a configuration of resources from a basestation 105. The resources could be used for beam recovery signaling. The UE 115 can detect a beam failure, such as loss of path or interference, on one or more active beams that are used to communicate with base station 105. In this case, the UE 115 could transmit a beam recovery message back to base station 105. The beam recovery message can be transmitted according the base station 105 configuration. In this case, the beam message is transmitted using the designated beam recovery resources. The configuration may be transmitted to the UE 115 by RRC signaling, or via a broadcast of system information from base station 105. The base station 105 may also indicate whether the beam recover resources are enabled or disallowed. For example, layer 1 (L1) signaling (i.e. PHY layer signaling) or layer 2 (L2) signaling), the UE 115 could transmit the beam message on different resources based upon whether or not the beam recuperation resources have been disabled.
“FIG. “FIG. 2 shows an example of a wireless communication system 200 that supports beam recovery using uplink resources in accordance to various aspects of this disclosure. Wireless communications system 200 comprises a base station 105 and a UE 115, which could be examples of the corresponding devices described in FIG. 1. Wireless communications system 200 can be used to transmit a beam recovery message.
“Wireless communication system 200 may operate within frequency ranges associated with beamformed transmissions from base station 105a to UE 115a. Wireless communications system 200, for example, may use mmW frequency bands. Signal processing techniques such as beamforming can be used to combine energy coherently and eliminate path losses. Base station 105-a might have multiple antennas. Each antenna can transmit or receive a phase-shifted signal. This means that certain areas may be constructively interfering with others while others are being destructively interfering with them. To steer transmissions in the desired direction, weights can be applied to phase-shifted signals. These techniques or similar techniques may be used to expand the coverage area 110-a from the base station, 105-a, or benefit wireless communications system 200.
“Transmit beams (205-a and205-b) are examples of beams through which data (e.g. control information or data) can be transmitted. Each transmit beam 205 can be directed from base station 110-a to a different area of the coverage area 110. In some cases, multiple beams may overlap. Transmit beams (205-a and205-b) can be transmitted simultaneously or at separate times. A UE 115-a can receive the information transmitted using transmit beams 205 and receive beams 210.
“UE 115-a, for example, may contain multiple antennas and form one (or more) receive beams 210. Each of the receive beams 210, 210, and 205 may receive one of these transmit beams 205a or 205b. For example, UE 115a could be placed within wireless communication system 200 so that UE 115a receives both beamformed transmit beacons 205. This scheme is sometimes called a “receive-diversity” scheme. Sometimes, each of the receive beams 220 may receive one transmit beam 205. For example, receive beam 210a may receive transmit beam 205-205 with different path loss and multipath effects. Each antenna of UE 115 may receive the transmit beam 205a with different phase shifts or path losses. This could be because the antennas at UE 115 may have received different phases of the transmit beam 205a. The appropriate combination of the received signals is done in one or more of the receive beams 210. A single transmit beam 205 may be received by a single receive beam (210).
A beam pair is a transmit beam 205 and a corresponding received beam 210. A beam pair can be established by cell acquisition (e.g. through synchronization signals), or through a beam refinement process where the UE 115?a and base station 105?a test various combinations of transmission beams and received beams until a suitable pair is found. The examples above are for downlink transmissions. However, similar concepts can be applied to uplink transmissions according to aspects of the disclosure. FIG. 2 illustrates the receive beams210. 2. may also represent transmit beams for the uplink signals from Ue 115-a. Base station 105-a can receive these uplink signals using one of several receive beams. Each beam pair can be associated with a signal type (e.g. base station 105 and UE 115 may prefer to communicate using a beam pair that has a higher signal quality).
High path loss is a major problem in certain wireless systems (e.g. mmW systems). To overcome this loss and increase communications efficiency, hybrid beamforming, which is not available in legacy systems (3G and 4G), can be used. Hybrid beamforming, for example, may allow multi-beam operation to users. This may increase the link budget (e.g. resource efficiency) as well as SNR within wireless communication system 200.
“Base station 105-a, UE 115 -a, and UE 115 -a can communicate in certain cases over one or more active beam pair, as described above. Each beam pair can carry one or more channels. One or more channels may be carried by each beam pair, including a physical-downlink shared channel (PDSCH), a control channel for physical downlink (PDCCH), and a control channel for physical uplink (PUCCH).
“A beam failure can occur in multi-beam operation when one or more active beam pair becomes misaligned. The misalignment could be caused by signal blockage or beam switch failure. Base station 105-a or UE 115 -a might not be able communicate (e.g. data or control information) with each other in such a situation.
“UE 115-a can detect beam failure in some cases by monitoring a subset or signals such as synchronization signal or reference signals. These signals could include a synchronization sign (e.g. an NR-SS), which includes a primary and secondary synchronization signals (SSS), and one or more reference signs (e.g. a mobility reference symbol (MRS). These signals could also include a synchronization block (SS block), which may include, for instance, the PSS and the SSS, as well as a physical broadcast channel. These signals can sometimes be multiplexed (e.g. time or frequency multiplexed), in the same area of a resource grid. One or more reference signals can be transmitted using multiport transmission in some cases (e.g. an analog beam could include up to eight-port digital transmission). UE 115 may attempt to connect with uplink resources in order to reconnect with the server cell upon detection of a beam fault (also known as a link problem). Uplink resources can be set up to allow base station 105-a to create a receive beam from the directions that the UE(s), 115 are transmitting.
In some systems, SR resources can be multiplexed (e.g. time or frequency multiplexed). With RACH resources, the sets of resources might overlap in time, but occupy different resource blocks. A control region may contain both SR and RACH resources. This may also be referred to alternatively as a RACH. Some systems may map the NRSS for an active beam to the RACH resources (e.g. each beam’s NRSS is mapped in turn to the RACH resources). To convey the beam recovery request, SR resources (e.g. RACH resources) may be used in the control area of a resource grid.
However, this implementation could have some drawbacks. The RACH region might not have enough information, for example, due to the RACH sharing resources with SR. Alternatively, beam recovery using RACH and SR resources can be associated with high latency. This is due to the fact that these resources are not always available. It may also result in relatively long times (e.g. 100 ms) until UE 115a is able send beam recovery information. UE 115 may not have access to these resources because RACH resources are contention-based. The beam recovery request information may be limited due to the limited resources available in the control area. In some systems, UE 115 a may be used to allocate additional resources, over which beam recovery information can be communicated to base station 105 -a.
“According to some aspects of the disclosure, base station 105a may assign resources (e.g. resource elements (REs),) to one or several UEs 115 so that beam recovery is not restricted to the NRSS associated resources within the control area. The configuration can be sent via RRC signaling or a system information broadcast in some cases. L1/L2 signaling can be used to enable or disable the configuration. UE 115 a can be triggered in certain cases to access additional resources during beam recovery (e.g. through a resource grant by base station 105 -a). The resources for beam recovery are not subject to contention. UE 115 may therefore access the designated resources after they have been granted by base station 105. The configuration could be unique to UE 115 or a group of UEs 115. Sometimes, the configuration can be traffic dependent. E.g. Base station 105-a might configure a group of UEs 115 that have uplink resources that are more frequent to reduce beam recovery delays. Alternatively, in a low traffic scenario (e.g. when UE 115 has a small amount of data to send), the SR resources within the RACH area may suffice. This is because delays might be easier to tolerate in such a situation. Base station 105-a might configure UEs 115 with a high SNR to use any beam from the uplink for beam recovery.
“In some cases, basestation 105-a might specify a SFN or periodicity, REs, and a slot, mini-slot, or SFI. for the uplink resources. The number of UEs 115 using the uplink beam can affect the configuration of the REs per beam. Base station 105-a might specify a maximum number of beam recovery requests that UE 115 a will make. This may be based on the number or other conditions (e.g. a timer). Base station 105 may in some cases configure higher frequency or longer time resources for certain beams than other beams, e.g. to support a larger payload. The configured resources could also be located in another region than the RACH.
“Base station (105-a) may indicate a relationship between downlink beacons and uplink resources. Base station 105-a could provide equivalent uplink resources to each downlink beam. In certain cases, downlink beams can be based on one or more of the following: an NR-SS or an MRS or a CSIRS (e.g., a periodic CSIRS). The present disclosure may allow for the association of respective reference signals with their own dedicated uplink resources. The frequency of the dedicated resources could be determined by the periodicity the associated reference signal. The periodicity of uplink resources can be greater, equal, or lower than that of associated reference signals. For example, the periodicity for uplink resources could be multiples (e.g., an int multiple) of the associated signal. There are many possible relationships between periodicities of reference signal and uplink resource that are not mentioned herein, including those that are based on a relationship between uplink resources or one or more reference signals. Sometimes, measurement reference signals, such as MRS or CSI-RS, may be transmitted more often than the NRSS.
“UE 115-a can determine beam failure on one of the active beams and use the configured resource to send a beam recover message. UE 115 may, for example, monitor a number of reference signals in order to determine if a beam loss has occurred. If so, the beam recovery message will be transmitted. The beam recovery message can be sent via one or more uplink resources, and/or in one/more beam directions. The beam recovery message could contain reference signals measurements from one or several beams, or one or two cells. These measurements can be made before or after beam failure is detected in some cases. In some cases, the frequency of the dedicated resources may be less than that of the reference signals. UE 115a can continue to measure reference signals while it waits for the dedicated resources. The reference signals could include NR-SS and MRS. The measurement results can include an indication of RSRQ, CQI and PMI as well as rank indicator (RI) in some cases. In some cases, UE 115a may provide direction information. For example, a mobility condition that includes UE 115a’s direction, a distance to base station 105a, and an orientation of UE 115a. UE panel information (e.g. number of antennas or arrays at UE 115?a).
“UE 115-a can specify a downlink beacon identifier in some cases (e.g., explicit and/or implicitly using appropriately mapped uplink resources to the given downlink beam). UE 115 may, for example, identify one or more candidate beams within the beam recovery message (e.g. using a beam identifier). This information can be used to recover beams. In these cases, the beam message may also include information about the signal quality of the candidate beams (e.g., using reference signals measured on candidate beams). UE 115-a can also send information in the beam recover request to indicate whether a candidate beam is present based on measurements.
“Base station 105 may receive one or several beam recovery messages from UE 115a. Base station 105 may receive a subset or all of the beam recovery messages. In some cases, multiple UEs 115 could transmit simultaneously over the same resources. Base station 105 may distinguish transmissions based upon a scrambling code (e.g. which may be based in a cell radio network temporary identifier C-RNTI for RRC-connected UEs 115). Base station 105 may reply with a confirmation that UE 115 has indicated a candidate beam or signal a different beam to be recovered. Base station 105 may choose the beam based on the measurement report in the beam recovery message. Base station 105-a might choose to use a different beam (e.g. a refined beam) if the measurement message indicates that UE 115 can use the same receive beam in order to receive the other beam. Base station 105 may choose a transmit beam based on uplink measurements at base station 95-a. A PDCCH sent to UE 115a could indicate that there is an additional reference signal for beam refinement. Other examples may indicate that a beam is not available for beam recovery.
“FIG. “FIG. A UE 115 may use the resource grid 300 as described in FIGS. 1. and 2. Resource grid 300 can be associated with a beam pair between a serving station 105 (not illustrated) and UE 115?b. For the sake of simplicity, some aspects of resource grid 300 were simplified. The arrangement and frequency of the resources below might differ from the ones shown in FIG. 3.”
“Resource grid 300 could include a subset of resources (305-a) and another subset (305-b) within a given system bandwidth. The subcarriers 310 may be transmitted over multiple symbol periods 315 (e.g. OFDM symbols). An RE is a block that spans one symbol period and one subcarrier (310). Alternativly, each block could span a group subcarriers 315 and one subframe (e.g. a TTI), so that each block can be called a resource block (RB). The units of frequency or time in the example are arbitrary and may not be used for any other purpose than to explain. The first subset 305-a could be an example control resource (i.e. resources over which control channel information can be transmitted). The first subset of resources (305-a) may include PUCCH or physical RACH transmissions (PRACH), from one or more UES 115. These channels may also be used to transmit the beam recovery message. The first subset of resources 305a could contain RACH resources 325 or SR resources 320. RACH resources 325 or SR resources 320 can be multiplexed in some cases so that they overlap in frequency or time.
“The second subset 305-b of resources may represent resources within a data area of the system bandwidth. The bandwidth of the second subset 305-b of resources may be greater than the bandwidth of the first subset 305-a. In certain cases, resources 305b could be used to carry PUSCH transmissions.
“UE 115-b might be able communicate with a base station 105 in some cases over multiple active beams (e.g. active beams 330 or 335 in this example). Each active beam can have an associated signal quality. In some cases, UE 115b may prefer to communicate with the serving station 105 over a stronger beam (e.g. active beam 330 which has comparatively higher SNR than other active beams). As shown in FIG. 3, each active beam 330 and 335 could be considered a downlink receiver beam. 2. Each active beam 330, 335 can be used to receive one of the reference signals (e.g. NR-SS or MRS), From the base station 105. UE 115b may monitor the reference signals in respective active beams 330, 335, (e.g. to detect a beam loss).
“Active beam 330 could experience a beam failure in some cases (e.g. signal blockage, movement UE 115b, etc.). UE 115b might not receive any reference signals from active beam 330. Sometimes, the UE 115b may try to report beam failure to the base station 105 using SR resource 320 or RACH resource 325. This means that each active beam 330, 335 might have an associated set SR resources 320 or RACH resources 325, over which beam recovery information can be transmitted. RACH resources 325 and SR resources 320 may not be found in resource grid 300. These resources could also be contention-based resources. UE 115b might not be able access them when they are available.
“In some cases, a basestation 105 may also or alternatively create dedicated resources within the second set of resources 305b to be used for beam recovery information. The dedicated resources can be mapped to specific reference signal and/or active beams 330, 335 in some cases. Active beam 330, for example, may be carrying one or more of NR?SS, MRS and CSI?RS. Each reference signal may have its own set of resources that can be used to relay beam failure information. One or more of these signal may have shared resources. UE 115b could be used to report NRSS failure of active beacon 330 using SR resources 320 and MRS failure active beam 330 using dedicated resources 340a. CSI-RS failure active beam 330 using dedicated resources 340b. It is possible to map other reference signals for the downlink active beam 333. An MRS/CSI-RS or NR-SS may be transmitted more often than an NRSS in some cases. Sometimes, the associated reference signals may be transmitted less often than the MRS and/or CSI-RS.
“Additionally, or alternatively different sets of resources can be reserved for beam failure recover requests for different beams. One or more dedicated uplink resource 345 could be used to transmit beam recovery information to active beam 335, in addition to the dedicated uplink resource 340 to active beam 330. Sometimes, dedicated uplink resources 345 and 340 may be used over the same blocks of resource, but they should be distinguished because active beams 335 and 330 may cover different directions. This frequency reuse is not possible with RACH resources 325. RACH resources 325 can be distributed in many directions. Multiple UEs 115 can transmit using a set of dedicated uplink resource 340, 345 in some cases. Each UE 115 could be associated with a different CRNTI so that each UE 115 can scramble transmissions over dedicated uplink resources 340 and 345 according to respective C-RNTIs. Multiplexing may not work with RACH resources 325. However, UEs 115 could use one or more of the same identifiers.
“In some cases the dedicated uplink resources 340 and 345 may be set to occur more often than the RACH resources 325, or the SR resource 320. The dedicated uplink resources 345, 340 may also support higher data rates, such as a longer duration, higher bandwidth, higher modulation, and coding schemes (MCS), or other options. The RACH resources 325 and the SR resources 320 are both lower than these dedicated uplink resources. The dedicated uplink resources 345 and 340 may be able carry additional beam recovery information as shown in FIG. 2. ”
“In certain cases, UE 115b may attempt to transmit a beam-recovery message over the SR resource 320. In certain cases, UE 115b might not be able access the SR resources 320. It may then attempt to access RACH 325. UE 115b may be given a configuration (e.g. via RRC signaling), specifying which resources will be used for beam recovery messages (e.g. which frequency and time they may be used), and UE 115b may decide to use the uplink resources 340 and 345. UE 115b can be triggered (e.g. via L1/L2 signals) to access these uplink resources 340 and 345.
“FIG. “FIG. The 400 process includes a UE 115c and a base station 105b. Each of these devices may be examples of the corresponding devices discussed above with reference to FIGS. 1. through 3. The process flow 400 could be an example of signaling uplink resources that are used to transmit a beam recovery message.
“At 405, UE 115 c and base station 105 b may establish a communication by using one or more active beams. Base station 105b at 410 may detect a communication parameter that is associated with one or several active beams. This could be used to identify the base station 105b communicating with UE 115c. Base station 105-b might identify a traffic level that is associated with UE 115 -c in some cases (e.g. a group of UEs 115). Base station 105-b could also identify an SNR associated to the communication with UE 115 c established at 405. Base station 105-b might identify a payload in some cases associated with uplink transmissions from UE 115 -c.
“At 415 the base station (105-b) may transmit (e.g. UE 115 -c may receive), a configuration for uplink beam resource recovery resources. Sometimes, the uplink beam resources are associated with different regions of resources than those that are used for transmission of random access messages (e.g. for RACH messages). Base station 105-b might transmit the configuration in some cases as part of RRC signaling. The configuration can also be transmitted via a system information broadcast.
“UE 115-c could receive the configuration either as part RRC signaling, or as part the system information broadcasted from base station 105 -b. The configuration of the uplink resource depends in some cases on one or more communication parameters at 410. The uplink resource configuration could be based on identified traffic levels and transmitted to one or more UEs 115. Alternately, the uplink configuration can be specific to UE 115c based upon the SNR associated UE 115c. The configuration may indicate additional beam recovery resources that are available for one or more beam-recovery messages, based at minimum on the identified payload. Sometimes, the configuration might indicate a set beams for each one or more beam-recovery messages.
Base station 105-b might identify one or more reference signal associated with a set downlink beams. This may allow it to identify a mapping between the uplink beam recovery resources, and the downlink beams based upon the reference signals. Base station 105b may indicate the mapping in the configuration at 415. Sometimes, the configuration may include an SFN corresponding the uplink beacon recovery resources, an SI corresponding the uplink beech recovery resources and a periodicity corresponding the uplinkbeam recovery resources.
“At 420 base station 105b may enable or disable the uplink beam recover resources for transmission of beam recovery messages. Sometimes, L1/L2 signaling may be used to indicate whether the resource is enabled or disabled. UE 115c at 425 may indicate a beam failure in one or more active beams that were used to establish the communication at 405
“At 430, UE 115 -c may optionally measure various signals received at base station 105 -b. These measurements can be made before or after the beam failure at 425 is identified. In certain cases, UE 115c may measure a set reference signals. One or more active beams at 405 may be used to associate the set of reference signals. The set of reference signals may include a synchronization signal or a MRS, a CSI RS, or a combination thereof. UE 115 c can determine a mobility condition that is associated with UE 115 c. This includes a direction of UE 115 c relative to base stations 105-b and UE 115 c’s orientation relative to base stations 105-b. It also may indicate a distance from base station 105 -b or a combination of both. UE 115 c can identify information about antenna arrays that correspond to one or more of the antenna arrays at UE 115 c. Sometimes, information about antenna arrays includes information about several antenna arrays located at UE 115.c.
“At 435, UE 115 -c may transmit (e.g. and base station 105 -b may receive), a beam recovery message according the received configuration using uplink beam recovery resources based upon the beam failure identified as 425. A beam failure recovery request may be included in the beam recovery message. Base station 105-b might receive one or more beam message on a set resources in one or several receive beam directions. In certain cases, UE 115 c may transmit the beam message on one or several resources in one or multiple beam directions. Aspects allow the beam recovery message to be transmitted using at most one of the plurality beams specified in the configuration at 415 (e.g. based on an SNR associated UE 115c). UE 115c may transmit, depending on the configuration at 415, an SR from base station 105b using uplink beam recovery resources. UE 115c may transmit the beam message in some cases based on the indication received at 415 that enables or disables use of uplink beam resources to transmission of the beam message.
“In some cases, the beam recovery message might include a measurement report that is based on measurements taken at 430. A measurement report could include, for instance, an RSRQ or CQI, PMI or rank (e.g. an RI). The beam recovery message can also include an indication of mobility conditions at 430. In some cases, the beam recovery message might include information about the antenna array information at 430. One example is that UE 115c could determine the identity of one or several downlink beams at base station 105b. This information may be included in the beam recovery message.
“Based on the beam recovery message at 435, base station 105b may determine the transmit beam direction at 440. Base station 105-b can perform measurements on uplink signal strength over one or more active beams to determine the transmit beam direction. Base station 105-b at 445 may transmit (e.g. and UE115-c may get) a message as a response to the transmitted beam recover message. The message may include an indication of one, or more, reference signals for beam refinement. This message can be transmitted to UE 115c in some cases using the transmit beam direction at 440.
“FIG. “FIG.5” 5 depicts a block diagram 500 for a wireless device 505 which supports uplink resources to beam recovery in accordance the various aspects of this disclosure. The wireless device 505 could be an example of aspects of a UE 115, as shown in FIG. 1. wireless device 505 could include receiver 510 and UE beam recovery manger 515. These components can be connected to one another, e.g. via one or more busses.
“Receiver510 may receive packets, user information, or control information as a result of various information channels (e.g. control channels, data channels and information about uplink resources for beam recuperation, etc.). The information may be transmitted to other parts of the device. One example of the aspects of transceiver 835 that may be used in receiver 510 is shown in FIG. 8.”
“UE beam Recovery Manager 515” may be an example of aspects in the UE beam Recovery Manager 815, as described with reference to FIG. 8. UE beam recovery manger 515 and/or some of its subcomponents can be implemented in hardware, software, firmware, or any combination thereof. The functions of the UE beam restoration manager 515, and/or at most some of its subcomponents, may be implemented in software by a processor. This includes a general-purpose CPU, a digital signal process (DSP), an app-specific integrated circuit, an ASIC, a field-programmable gate array, (FPGA), or any other programmable device.
“The UE beam recover manager 515 and/or some of its subcomponents can be physically located in various positions. Some functions may even be distributed so that they are executed at different locations by one or more devices. In accordance with different aspects of the disclosure, UE beam Recovery Manager 515 and/or at most some of its subcomponents could be a distinct component. In some cases, UE beam Recovery Manager 515 and/or at most one of its subcomponents can be combined with other hardware components such as an I/O, transceiver, network server, another computing device, or a combination of these components in accordance to various aspects of this disclosure.
“UE beam Recovery Manager 515” may receive a configuration to beam recovery resources. It will identify a beam loss of one or more active beams that are used to communicate to a base station 105 and send, according to the received configuration to the base station 105, a beam restoration message using the beam recovery resource based on the identified failure.
“Transmitter 520 can transmit signals that are generated by other parts of the device. The transmitter 520 can be colocated with the receiver 510 of a transceiver modules. The transmitter 520 could be one example of the transceiver 835 aspects described in FIG. 8. The transmitter 520 can include one antenna or a group of antennas.
“FIG. “FIG. 6” shows a block diagram 600 for a wireless device 605 which supports uplink resources to beam recovery in accordance the various aspects of this disclosure. The wireless device 605 could be one example of aspects of a wireless 505 or a UE 115, as shown in FIGS. 1. and 5. wireless devices 605 could include receiver 610 and UE beam recovery managers 615. The transmitter 620 may also be included in wireless device 605. These components can be connected to one another, e.g. via one or more busses.
“Receiver610 may receive packets, user information, or control information as a result of various information channels (e.g. control channels, data channels and information about uplink resources for beam recuperation, etc.). The information may be transmitted to other parts of the device. A representative example of transceiver 835 aspects may be the receiver 610, which is shown in FIG. 8.”
“UE beam Recovery Manager 615” may be an example of aspects in the UE beam Recovery Manager 815, as described with reference to FIG. 8. UE beam recovery manger 615 and/or some of its subcomponents can be implemented in hardware, software, firmware, or any combination thereof. The functions of the UE beam restoration manager 615, and/or at most some of its subcomponents, may be implemented in software by a processor. This includes a general-purpose CPU, a digital signal process (DSP), an app-specific integrated circuit, an ASIC, a field-programmable gate array, (FPGA), or any other programmable device.
“The UE beam recover manager 615 and/or some of its subcomponents can be physically located in various positions. Some functions may even be distributed so that they are executed at different locations by one or more devices. In accordance with different aspects of the disclosure, UE beam Recovery Manager 615 and/or at most some of its subcomponents could be a distinct component. In some cases, UE beam management manager 615 or at least one of its subcomponents can be combined with other hardware components such as an I/O, transceiver, network server, another computing device, or a combination of these components according to various aspects of this disclosure. UE beam management manager 615 could also include resource configuration component 625 and beam failure component 630.
“Resource configuration element 625 may be able to receive a configuration for beam-recovery resources. Receiving the configuration for beam recovery resources may be done as part RRC signaling from base station105 or as part a system information broadcast from base station105. The configuration might include a UE-specific configuration to recover beam resources. Sometimes, the configuration may indicate a set beams that will transmit a beam recovery message. This indication could be based on the UE 115’s SNR. The configuration might include an indication of the SFN corresponding the beam recover resources, an SFI that corresponds to the beam resources, a periodicity that corresponds to the beam resources, one or more REs that correspond to the beam resources, or a combination of these. Sometimes, the beam recovery resources might occupy a different region than the second region of resources used for transmission of random access messages (e.g., RACH). The configuration might indicate a mapping between the downlink beam from base station 105, and the beam recovery resource.
“Beam failure component (630) may detect a beam failure in one or more active beams that are used to communicate with base station 105. UE beam recovery manager 635 may transmit, based on the received configuration, a beam loss message to base station 105. In certain cases, UE beam message manager 635 might receive an indication that allows the beam resources to be used for transmission of the beam message. The indication is used for transmitting the beam message. UE beam recovery manager 635 could also receive an indication disallowing the beam recovery resources to transmit the beam message. Sending the beam recovery message from the base station to 105 might include sending the message using at most one of the beams identified by the base station. Sometimes, the beam recovery message can be transmitted to the base station at 105 by transmitting it on one or more resources using one or more beam directions.
“Transmitter 620 could transmit signals that are generated by other parts of the device. The transmitter 620 could be colocated with the receiver 610 of a transceiver modules. The transmitter 620 could be one example of aspects of transceiver 835, as shown in FIG. 8. The transmitter 620 can include one antenna or a group of antennas.
“FIG. “FIG. 7” shows a block diagram 700 for a UE beam recover manager 715, which supports uplink resources to beam recovery in accordance the various aspects of this disclosure. The UE bea recovery manager 715 could represent one of the UE beam management managers 515, 615 or 815 as described in FIGS. 5, 6, and 8 5, 6, and 8. The functions of the UE beam restoration manager 715, and/or at most some of its subcomponents, may be implemented in software by a processor. This includes a general-purpose CPU, a digital signal process (DSP), an app-specific integrated circuit, an ASIC, a field-programmable gate array, (FPGA), or other programmable device.
“The UE beam recover manager 715 and/or some of its subcomponents can be physically located in various positions. Some functions may even be distributed so that they are executed at different locations by one or more devices. In accordance with different aspects of the disclosure, UE beam recover manager 715 and/or some of its subcomponents could be a distinct component. UE beam recovery manger 715, at least one of its subcomponents, and/or some of them, may be combined with other hardware components. This includes, but is not limited to, an I/O component, a transmitter, a network server or another computing device. Or a combination of these components according to various aspects of this disclosure. The UE beam Recovery Manager 715 could include resource configuration component 720 and beam failure component 725. It also may contain scheduling request component 740, beam refinement part 735, scheduling request piece 740, signal measurement portion 745, mobility condition component 750 and antenna information component 755. It also includes downlink beam component 760. These modules can communicate with each other directly or indirectly (e.g. via one or several buses).
“Resource configuration element 720 may be able to receive a configuration for beam-recovery resources. Receiving the configuration for beam recovery resources may be done as part RRC signaling from base station105 or as part a system information broadcast from base station105. The configuration might include a UE-specific configuration to recover beam resources. Sometimes, the configuration may indicate a set beams that will transmit a beam recovery message. This indication could be based on the UE 115’s SNR. The configuration might include an indication of the SFN corresponding the beam recover resources, an SFI that corresponds to the beam resources, a periodicity that corresponds to the beam resources, one or more REs that correspond to the beam resources, or a combination of these. Sometimes, the beam recovery resources might occupy a different region than the second region of resources used for transmission of random access messages (e.g., RACH). The configuration might indicate a mapping between the downlink beam from base station 105, and the beam recovery resource.
“Beam failure component 725 might identify a beam loss of one or more active beams that are used to communicate with base station 105. UE beam recovery manager 730 can transmit, based on the received configuration, a beam loss message to base station 105. Sometimes, UE beam message manager 730 might receive an indication that allows the beam resources to be used for transmission of the beam message. The indication is used in transmitting the beam message. UE beam recovery manager 730 could also receive an indication disallowing the beam recovery resources to transmit the beam message. Sending the beam recovery message from the base station to 105 might include sending the message using at most one of the beams identified by the base station. Sometimes, the beam recovery message can be transmitted to the base station at 105 by transmitting it on one or more resources using one or more beam directions.
Summary for “Uplink resources to beam recovery”
“The following applies generally to wireless communication and, more specifically, to uplink resources to beam recovery.”
Wireless communications systems are used to transmit various communication types, including voice, video, packet data and messaging. These systems can support communication with multiple users by sharing system resources (e.g. time, frequency and power). Multiple-access systems can include code division multiple acces (CDMA), time division multiple accessibility (TDMA), frequency division multiple Access (FDMA), and orthogonal frequency division multiple access OFDMA systems. These systems may also be used to support communication with multiple users by sharing system resources (e.g., time, frequency, and power). Wireless multiple-access communication systems may have a number base stations or access nodes that support communication for multiple communication devices. These communication devices may also be known as user equipment (UE).
“Some wireless communication systems, such as NR systems, may operate in frequency bands that allow beamformed transmissions between wireless device. Transmissions in millimeter-wave (mmW), for example, may have higher signal attenuation (e.g. path loss) than transmissions in non mmW frequency ranges. Signal processing techniques like beamforming can be used to combine energy coherently, and overcome path losses in these systems. Sometimes, misalignment can occur between active beams from two wireless devices. A UE can detect a beam misalignment or beam failure and attempt to connect with uplink resources. However, some of the uplink resources used for beam recovery may have limited throughput, high latency or both. It may therefore be desirable to improve uplink resource allocation techniques for beam recovery.
“The techniques described herein relate to improved methods and systems, devices, and apparatuses that support beam recovery uplink resources. The described techniques allow for the configuration of dedicated resources to enable one or more UEs transmit a beam recovery request from a base station. These resources can be configured dynamically, semi-statically by the base station and communicated with one or more UEs. Using the techniques described herein, a UE can determine a beam failure (e.g. due to misalignment) on one or more active beams and then use the configured resources for the beam recovery message. One or more downlink beams, which may each have an associated reference signal, may be linked with uplink resources that the UE can use to transmit the beam recovery message. The beam recovery message could contain measurements or other information that may be helpful to the base station in reconnecting with UE.
“A method for wireless communication” is described. This may involve receiving a configuration to beam recovery resources, identifying a beam loss of one or more active beams that are used to communicate with a base stations, and then transmitting a beam recovery message using the beam resources determined to be at least partially responsible for the beam failure to the base station.
“A wireless communication apparatus is described. The apparatus can include means to receive a configuration for beam recover resources, means to identify a beam failure in one or more active beams that are used to communicate with a base stations, and means to transmit, according to the received configuration to the base station, a beam message using the beam recovery resource based at most in part on the identified beam loss.
“Another apparatus is described for wireless communication. The apparatus can include a processor and memory for electronic communication with it. Instructions may be stored in the memory. The instructions can be used to instruct the processor to identify a beam loss in one or more active beams that are being used to communicate with a base stations and to transmit, according the received configuration, a beam restoration message to the base station using beam recovery resources that are at least partially based on the identified beam failure.
A non-transitory computer-readable medium for wireless communication” is described. Instructions may be included in the non-transitory computer readable medium that allow a processor to obtain a configuration for beam recover resources, identify an active beam failure, and then transmit, according the received configuration, to the base station a beam recovery message using the beam resources determined at least partially from the identified beam failure.
“Some of the non-transitory computer readable media and methods described above may also include features, means or instructions for receiving a message back from the base station. The message includes an indication of a set reference signals for beam refinement. The beam recovery message is transmitted to the base station using some of the above-described methods, apparatuses, and non-transitory computers-readable media.
“In some cases of the non-transitory computer readable medium and the apparatus described above, receiving configurations for beam recovery resources includes: receiving the configuration either as part radio resource control (RRC), signaling from base station, or as part a system information broadcast from base station. The non-transitory computer readable medium, apparatus and method described above may also include features, means or instructions that enable the reception of an indication that allows the beam to recover resources to be used for transmission of the beam message. In this case, transmitting the beam message may be at least partially based on the indication.
“Some examples, of the non-transitory computer readable medium and method described above, may also include features, means or instructions for receiving an indicator that disables use of beam recovery resources for transmission of the beam message. In this case, transmitting the beam message may be at least partially based on the indication. The configuration may include a UE-specific configuration of the beam recovery resources. The configuration is used in some of the above-described methods, apparatuses, and non-transitory computer readable media. It includes an indication of a plurality beams to transmit the beam-recovery message. This indication is based at most in part on a signal?to-noise ratio, (SNR), associated with the UE. In other words, transmitting beam recovery messages involves: using at least one beam from the plurality.
“In some cases of the non-transitory computer readable medium, apparatus and method described above, the configuration includes an indication of a system number (SFN), corresponding beam recovery resource, a subframeindex (SFI) which corresponds to beam recovery resource, a periodicity that corresponds to beam recovery resources, one (or more) resource elements (REs) or a combination thereof.”
“In some cases of the non-transitory computer readable medium and method described above, the beam recover resources occupy a first area of resources that can be different from the second region of resources used for transmission of random access messages. The configuration may include an indication of a mapping between the downlink beam from base station and beam recovery resources in some of the above-described methods, apparatuses, and non-transitory computers-readable media.
“Some examples of the non-transitory computer readable medium and method described above may also include processes, features or instructions for transmitting, depending on the received configuration, an order (SR) to base station using beam recovery resources. The non-transitory computer readable medium and the apparatus described may also include the following: processes, features, methods, or instructions for measuring a set or reference signals. These reference signals are associated with one or more active beams. In this case, the beam recovery message includes a measurement report that is at least partially based on the measured signals.
“In some cases of the method, apparatus and non-transitory computers-readable medium described above, a measurement report includes a reference signals received power (RSRP), quality (RSRQ), channel quality indicator(CQI), precoding matrix indicator, PMI, or a combination thereof. The set of reference signals may include a synchronization, a mobility, a channel information reference signal (CSIRS) or a combination of both.
“Some of the methods, apparatus, and nontransitory computer-readable media described above may also include processes, features or instructions for determining a mobile condition associated with UE. The mobility condition of UE comprises a direction of UE relative to base station, an orientation or distance from base station or a combination thereof. In the beam recovery message, an indication of the mobility conditions is included. The method, apparatus and non-transitory computer readable medium may also include features, means or instructions for identifying antenna information corresponding one or more antennas located at the UE. In these cases, the beam recovery message contains an indication of the antenna information.
“In some cases of the non-transitory computer readable medium and method described above, the antenna array data comprises a number antenna arrays located at UE. The method, apparatus and non-transitory computers-readable medium may also include features, means or instructions for determining the identity of a downlink beacon from the base station. In these cases, the beam recovery message includes an indication of the identity.
“A method for wireless communication” is described. This may involve communicating with one or several UEs using one, or more active beams and transmitting a configuration to beam recovery resources. The beam recovery messages can be received on the beam resources.
“A wireless communication apparatus is described. The apparatus can include means to communicate with one or several UEs using one, or more active beams. It also includes means for transmitting a configuration of beam recovery resources and means for receiving one, more or all of the beam recovery messages on beam recovery resources. These messages indicate a beam failure of at most one of the one, or more, active beams.
“Another apparatus is described for wireless communication. The apparatus can include a processor and memory for electronic communication with it. Instructions may be stored in the memory. Instructions may be used to instruct the processor to communicate one or several UEs using one, more or all active beams, to transmit a configuration to beam recovery resources and to receive one or multiple beam recovery messages on beam recovery resources. These messages indicate a beam failure of at most one of the active beams.
“A non-transitory computer-readable medium for wireless communication” is described. Instructions may be included that allow a processor to communicate using one or multiple active beams with one or other UEs and transmit a configuration to beam recovery resources. The processor can also receive one or several beam recovery messages on beam recovery resources. These messages indicate a beam failure of at most one of the active beams.
“Some examples of the non-transitory computer readable medium and method described above may also include features, means or instructions for sending a message to a UE to respond to one or more beam-recovery messages. The message will contain an indication of a set reference signals for beam refinement. The non-transitory computer readable medium and the method described may also include features, means or instructions to receive the one or more beam-recovery messages. This includes receiving a measurement report. The non-transitory computer readable medium, apparatus and method described above may also include features, means or instructions to determine a transmit beam direction using at least part of the measurement report. The method, apparatus and non-transitory computers-readable medium may also include features, means or instructions for transmitting the message from the UE using the determined transmit beacon direction.
“Some of the non-transitory computer readable media, apparatus and method described above may also include processes, features or means for measuring uplink signals over one or more active beams. The non-transitory computer readable medium and apparatus described above may also include features, means or instructions for determining a transmit be direction based at minimum in part on measurements of uplink signals. In this case, the transmit beam direction may be used to transmit the message to the UE. Receiving the one or several beam recovery messages is one way to receive the apparatus, method and non-transitory information-readable medium.
“Some examples of the non-transitory computer readable medium and method described above include transmitting the configuration to the beam recovery resources as part RRC signaling, or in a system information broadcast. The non-transitory computerreadable medium, apparatus and method described above could also include features, means or instructions for transmitting an indicator that enables the beam recovery resources to be used for one or more beam message recovery messages. Receiving the one or several beam recovery messages may be based at most in part on this indication.
“Some of the non-transitory computer readable media, apparatus and methods described above may also include features, means or instructions for transmitting an indicator that disables the use beam recovery resources for one or more of the one or two beam recovery messages. Receiving the one or several beam recovery messages may be based at most in part on the indication. In some cases, the apparatus and non-transitory medium described above allow for identification of a traffic level that is associated with a subset or more UEs. The configuration for beam recovery resources is transmitted to this subset using the traffic level.
“Some examples of the non-transitory computer readable medium and method described above may also include features, means or instructions for identifying an SNR associating with a UE. In such cases, the configuration includes a UE-specific configuration beam recovery resources based at minimum in part on the identified SNR. The configuration may include an indication that there are multiple beams for each one or more of the beam recovery messages.
“Some examples of the non-transitory computer readable medium and method described above may also include features, means or instructions for identifying a payment load associated with uplink transmissions from one or more UEs. The configuration includes an indication of additional beam recover resources that have been allocated to the one or several beam recovery messages based at most in part on the identified payload. The beam recovery resources can be associated with one region of resources, which may be different than the second region that is used for transmission of random access messages.
“Some examples of the non-transitory computer readable medium, apparatus and method described above may also include processes, features or means for identifying one of the reference signals associated with a series of downlink beams. The method, apparatus and non-transitory computers-readable medium may also include features, means or instructions to identify a mapping between beam recovery resources, set of downlink beams, and the configuration, which is based at minimum in part on one or more reference signal.
“Some wireless communication systems can operate in frequency bands that allow beamformed transmissions between wireless device. Communications in the mmW frequency band may experience higher signal attenuation (e.g. path loss) than communications in other frequencies. Signal processing techniques like beamforming can be used to combine energy coherently, and overcome path losses in these systems. Wireless devices such as a base station and UE may be able communicate with each other over active beams. These beams may correspond to the transmit beam used by the transmitting device and the receive beam at the receiving device (e.g., comprising an active beam pair). Sometimes, the active beam pair(s), such as a beam switch failure, signal blockage, may be misaligned so that the UE or base station are unable to communicate over the obstructed active pair(s). The beam failure may be detected by a UE, for example, by monitoring a subset or reference signals on active beams that are used to communicate with base station.
The UE may require resources to reconnect with the serving cells. These may include time, frequency and/or a beam. The UE may use certain uplink resources to connect with the cell in a multi-beam system. A UE might default to using SR or random access channel resources (RACH) to transmit a beam recovery request. These resources can have a limited throughput or high latency, due to contention-based resources, or because they are available with a low periodicity. Some systems support the configuration of one or multiple sets of dedicated resources to a UE (or multiple) in order to transmit beam recovery requests. This may allow for faster, stronger, and more efficient recovery.
“The beam recovery message transmission techniques described herein can be achieved using the dedicated resources that are available. A UE may, for example, receive a configuration from a base station for uplink resources. The uplink resources could be used for beam recovery signaling. A beam failure may be identified by the UE, which may include path loss or interference on one or more active beams. The UE can then transmit a beam recovery message (to the base station) to indicate this. The beam recovery message can be sent according to the base station’s configuration. In this case, the beam message will be transmitted using the designated beam recovery resources. The configuration may be transmitted to the UE via RRC or system information broadcasts from the base station. The base station may also indicate whether the beam resources are being used. For example, lower layer signaling may be used to enable or disable the beam recovery resource. In this case, the UE can transmit the beam message on different resources based on whether or not the beam resources have been disabled. The UE can monitor the base station for a response to the beam request message.
“Aspects are first described in the context a wireless communication system. Additional examples include a uplink resource grid, and a process flow to transmit a beam recovery message. The disclosure is further illustrated and described using apparatus diagrams, system diagrams and flowcharts that pertain to beam recovery uplink resources.
“FIG. “FIG. 1 illustrates a wireless communication system 100 according to various aspects of this disclosure. Wireless communications system 100 comprises base stations 105, core networks 130, and UEs 115. The wireless communications system 100 could be LTE, LTE Advanced (LTE A) network, or a NR network. Wireless communications system 100 can be used to support ultra-reliable communications (i.e. mission critical), enhanced broadband communications, and communications that are low-cost and complex. Wireless communications system 100 could support efficient uplink resource utilization for beam recovery.
“Base stations 105 can wirelessly communicate with UEs 115 using one or more base station antennas. Each base station 105 can provide coverage in a specific geographic area 110. The communication links 125 in wireless communications system 100 can include uplink transmissions between a UE 115 and a base stations 105 or downlink transmissions between a basestation 105 and a UE 115. Multiplexing control information and data on an uplink channel, or downlink, may be possible according to different techniques. Multiplexing control information and data on a downlink channel may be possible using various techniques. For example, time division multiplexing techniques (TDM), frequency division multiplexing techniques (FDM), or hybrid TDM/FDM techniques. ”
The UE 115 can be distributed throughout the wireless communications network 100. Each UE 115 could be mobile or stationary. A UE 115 can also be called a mobile station or subscriber station. Each UE 115 could be stationary or mobile. A UE 115 could also refer to a cellular phone or a personal digital assistant (PDA), a wireless device, a wireless communication device and a handheld computer, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a client, a mobile client, or some other suitable terminology.
“The core network 130 could provide user authentication, access authorization and tracking, Internet Protocol connectivity, as well as other access, routing or mobility functions. Subcomponents, such as a basestation 105, may be included in at least some network devices. This could include an access network entity (ANC), which may be an example access node controller. Each access network entity may communicate with a number of UEs 115 through a number of other access network transmission entities, each of which may be an example of a smart radio head, or a transmission/reception point (TRP). In some configurations, different functions of an access network entity (or base station 105) may be spread across multiple network devices (e.g. radio heads and access controllers) or combined into one network device (e.g. a base station 105)
“Wireless communication system 100 may operate at ultra-high frequencies (UHF), using frequency bands ranging from 700 MHz up to 2600MHz (2.6GHz), though in certain cases wireless local area networks may use frequencies up to 4GHz. The decimeter band may also be called this region, as its wavelengths are approximately one to one meter long. UHF waves can propagate mostly by line-of-sight, but may be blocked by buildings or other environmental features. The waves can penetrate walls enough to provide service to UEs 115 indoors. Transmission of UHF waves has a shorter range and smaller antennas than transmission using the higher frequencies (and longer waves), portion of the spectrum. Wireless communications system 100 can also use extremely high frequency (EHF), portions of the spectrum in certain cases (e.g. 30 GHz to 300GHz). This area may also be called the millimeter spectrum, as it has wavelengths that range from one millimeter up to one centimeter long. EHF antennas can be smaller and less spaced than UHF antennas. This may allow for the use of an antenna array within a UE 115 in certain cases (e.g. for directional beamforming). EHF transmissions can be subject to greater atmospheric attenuation, and may have a shorter range than UHF transmissions.
“Wireless communications 100 may support mmW communications between base stations 105 and UEs 115. Multiple antennas may be used to beamform devices operating in the mmW and EHF bands. A base station 105 can use multiple antennas or arrays to perform beamforming operations in order to transmit directional information with a UE 115. Beamforming, also known as spatial filtering and directional transmission, is a signal processing technique that can be used at a transmitter (e.g. A base station 105, to steer and shape an antenna beam in the direction desired by a target receiver (e.g. a UE 115. Combining elements in an antenna array so that transmitted signals from certain angles experience constructive interference and others experience destructive interference may help achieve this effect.
Multi-input multiple output (MIMO) wireless systems utilize a transmission scheme that links a transmitter (e.g. A base station 105, and a receiver (e.g. a UE 115, where both receiver and transmitter are equipped with multiple antennas. Beamforming may be used in some parts of wireless communications system 100. Base station 105 might have an antenna array that has a number rows and columns of antenna ports. This antenna array may be used by base station 105 for beamforming its communication with UE 115. Multiple transmissions of signals may occur in different directions. Each transmission could be be beamformed differently. A mmW receiver, such as a UE 115, may attempt multiple beams (e.g. antenna subarrays), while simultaneously receiving the synchronization signal.
“In certain cases, antennas from a base station 105 and UE 115 might be placed within one or more antenna arrays (e.g. panels), which could support beamforming or MIMO operation. An antenna tower, or an antenna assembly that houses multiple antenna arrays or base station antennas, may contain one or more of these antennas. Antennas and antenna arrays that are associated with base station 105 can be found in different geographic locations. Multiple antennas or arrays may be used by a base station 105 to perform beamforming operations in order to transmit directional information with a UE 115.
“In certain cases, wireless communications system 100 could be a packet-based network operating according to a layer protocol stack. The user plane may have IP-based communications at the bearer layer or Packet Data Consvergence Protocol (PDCP). In some cases, a radio link control layer (RLC), may perform packet segmentation and reassembly in order to communicate over logical channel. Medium access control (MAC), a layer that handles priority handling and multiplexing logical channels into transport channel, may be used. To improve link efficiency, the MAC layer can also use hybrid automated repeat request (HARD). The RRC protocol layer in the control plane may establish, configure, and maintain an RRC connection between a UE 115, a network device or core network 130 that supports radio bearers for user-plan data. Transport channels can be mapped to physical channels at the physical layer (PHY).
A resource element can be composed of one subcarrier and one symbol period (e.g., 15 kHz frequency range). A resource block can contain 12 consecutive subcarriers within the frequency domain. For a normal cyclic prefix (OFDM) symbol in each orthogonal frequency Division Multiplexed (OFDM), 7 consecutive OFDM symbols in time domain (1 slot), which is 84 resource elements. Modulation scheme (the combination of symbols that can be selected in each symbol period) may affect the number of bits each resource element can carry. The data rate of UE 115 may increase if it receives more resource blocks and has a higher modulation scheme.
“Wireless communications systems 100 may allow operation on multiple carriers or cells, which is known as carrier aggregation (CA), or multi-carrier operation. An operator may also be called a component carrier (CC), layer, channel, or channel. The terms “carrier”,?? ?component carrier,? ?cell,? ?cell?,? These terms may be interchangeable. A UE 115 can be configured with multiple downlink CCs, and one or more of the uplink CCs to enable carrier aggregation. Carrier aggregation can be used with either frequency division duplexed or time division duplexed component carriers.
“Wireless communications system 100 may use enhanced component carriers (eCCs) in certain cases. An eCC can be distinguished by one or more of the following features: a wider bandwidth, shorter symbol durations, shorter TTIs and modified control channel configurations. An eCC can be associated with a carrier aggregation setup or a dual connectivity configuration. This is when multiple serving cells have a suboptimal backhaul link. An eCC can also be used in unlicensed or shared spectrum, where more than one operator has access to the spectrum. A eCC with a large bandwidth can include one or more segments. UEs 115 may also be able to use the spectrum in unlicensed or shared spectrum.
An NR shared spectrum system may use a shared radio frequency band. An NR shared spectrum can use any combination of licensed, unlicensed, or shared spectrums. Flexibility in eCC symbol length and subcarrier spacing may permit the use of eCC across multiple frequencies. Some examples show that NR shared spectrum can increase spectrum utilization and spectral efficacy, particularly through dynamic vertical (e.g. across frequency) or horizontal (e.g. across time) sharing resources.
Wireless communications system 100 can use both licensed and unlicensed radio frequency bands in certain cases. Wireless communications system 100, for example, may use LTE License Assisted Access or LTE Unlicensed radio access technology (LTE U), or NR technology in unlicensed bands such as the 5GHz Industrial, Scientific and Medical (ISM). Wireless devices, such as base stations (105) and UEs (115), may use listen-before-talk procedures to ensure that the channel is clear before they transmit data. Sometimes, operations in unlicensed band may be based upon a CA configuration along with CCs operating within a licensed spectrum. Unlicensed spectrum operations may include uplink transmissions or downlink transmissions. Duplexing in unlicensed frequency can be done using FDD, TDD, or a combination of both.
“Beam recovery messages can be transmitted in wireless communications system 100 using resources (e.g. uplink resources). A UE 115 may, for example, receive a configuration of resources from a basestation 105. The resources could be used for beam recovery signaling. The UE 115 can detect a beam failure, such as loss of path or interference, on one or more active beams that are used to communicate with base station 105. In this case, the UE 115 could transmit a beam recovery message back to base station 105. The beam recovery message can be transmitted according the base station 105 configuration. In this case, the beam message is transmitted using the designated beam recovery resources. The configuration may be transmitted to the UE 115 by RRC signaling, or via a broadcast of system information from base station 105. The base station 105 may also indicate whether the beam recover resources are enabled or disallowed. For example, layer 1 (L1) signaling (i.e. PHY layer signaling) or layer 2 (L2) signaling), the UE 115 could transmit the beam message on different resources based upon whether or not the beam recuperation resources have been disabled.
“FIG. “FIG. 2 shows an example of a wireless communication system 200 that supports beam recovery using uplink resources in accordance to various aspects of this disclosure. Wireless communications system 200 comprises a base station 105 and a UE 115, which could be examples of the corresponding devices described in FIG. 1. Wireless communications system 200 can be used to transmit a beam recovery message.
“Wireless communication system 200 may operate within frequency ranges associated with beamformed transmissions from base station 105a to UE 115a. Wireless communications system 200, for example, may use mmW frequency bands. Signal processing techniques such as beamforming can be used to combine energy coherently and eliminate path losses. Base station 105-a might have multiple antennas. Each antenna can transmit or receive a phase-shifted signal. This means that certain areas may be constructively interfering with others while others are being destructively interfering with them. To steer transmissions in the desired direction, weights can be applied to phase-shifted signals. These techniques or similar techniques may be used to expand the coverage area 110-a from the base station, 105-a, or benefit wireless communications system 200.
“Transmit beams (205-a and205-b) are examples of beams through which data (e.g. control information or data) can be transmitted. Each transmit beam 205 can be directed from base station 110-a to a different area of the coverage area 110. In some cases, multiple beams may overlap. Transmit beams (205-a and205-b) can be transmitted simultaneously or at separate times. A UE 115-a can receive the information transmitted using transmit beams 205 and receive beams 210.
“UE 115-a, for example, may contain multiple antennas and form one (or more) receive beams 210. Each of the receive beams 210, 210, and 205 may receive one of these transmit beams 205a or 205b. For example, UE 115a could be placed within wireless communication system 200 so that UE 115a receives both beamformed transmit beacons 205. This scheme is sometimes called a “receive-diversity” scheme. Sometimes, each of the receive beams 220 may receive one transmit beam 205. For example, receive beam 210a may receive transmit beam 205-205 with different path loss and multipath effects. Each antenna of UE 115 may receive the transmit beam 205a with different phase shifts or path losses. This could be because the antennas at UE 115 may have received different phases of the transmit beam 205a. The appropriate combination of the received signals is done in one or more of the receive beams 210. A single transmit beam 205 may be received by a single receive beam (210).
A beam pair is a transmit beam 205 and a corresponding received beam 210. A beam pair can be established by cell acquisition (e.g. through synchronization signals), or through a beam refinement process where the UE 115?a and base station 105?a test various combinations of transmission beams and received beams until a suitable pair is found. The examples above are for downlink transmissions. However, similar concepts can be applied to uplink transmissions according to aspects of the disclosure. FIG. 2 illustrates the receive beams210. 2. may also represent transmit beams for the uplink signals from Ue 115-a. Base station 105-a can receive these uplink signals using one of several receive beams. Each beam pair can be associated with a signal type (e.g. base station 105 and UE 115 may prefer to communicate using a beam pair that has a higher signal quality).
High path loss is a major problem in certain wireless systems (e.g. mmW systems). To overcome this loss and increase communications efficiency, hybrid beamforming, which is not available in legacy systems (3G and 4G), can be used. Hybrid beamforming, for example, may allow multi-beam operation to users. This may increase the link budget (e.g. resource efficiency) as well as SNR within wireless communication system 200.
“Base station 105-a, UE 115 -a, and UE 115 -a can communicate in certain cases over one or more active beam pair, as described above. Each beam pair can carry one or more channels. One or more channels may be carried by each beam pair, including a physical-downlink shared channel (PDSCH), a control channel for physical downlink (PDCCH), and a control channel for physical uplink (PUCCH).
“A beam failure can occur in multi-beam operation when one or more active beam pair becomes misaligned. The misalignment could be caused by signal blockage or beam switch failure. Base station 105-a or UE 115 -a might not be able communicate (e.g. data or control information) with each other in such a situation.
“UE 115-a can detect beam failure in some cases by monitoring a subset or signals such as synchronization signal or reference signals. These signals could include a synchronization sign (e.g. an NR-SS), which includes a primary and secondary synchronization signals (SSS), and one or more reference signs (e.g. a mobility reference symbol (MRS). These signals could also include a synchronization block (SS block), which may include, for instance, the PSS and the SSS, as well as a physical broadcast channel. These signals can sometimes be multiplexed (e.g. time or frequency multiplexed), in the same area of a resource grid. One or more reference signals can be transmitted using multiport transmission in some cases (e.g. an analog beam could include up to eight-port digital transmission). UE 115 may attempt to connect with uplink resources in order to reconnect with the server cell upon detection of a beam fault (also known as a link problem). Uplink resources can be set up to allow base station 105-a to create a receive beam from the directions that the UE(s), 115 are transmitting.
In some systems, SR resources can be multiplexed (e.g. time or frequency multiplexed). With RACH resources, the sets of resources might overlap in time, but occupy different resource blocks. A control region may contain both SR and RACH resources. This may also be referred to alternatively as a RACH. Some systems may map the NRSS for an active beam to the RACH resources (e.g. each beam’s NRSS is mapped in turn to the RACH resources). To convey the beam recovery request, SR resources (e.g. RACH resources) may be used in the control area of a resource grid.
However, this implementation could have some drawbacks. The RACH region might not have enough information, for example, due to the RACH sharing resources with SR. Alternatively, beam recovery using RACH and SR resources can be associated with high latency. This is due to the fact that these resources are not always available. It may also result in relatively long times (e.g. 100 ms) until UE 115a is able send beam recovery information. UE 115 may not have access to these resources because RACH resources are contention-based. The beam recovery request information may be limited due to the limited resources available in the control area. In some systems, UE 115 a may be used to allocate additional resources, over which beam recovery information can be communicated to base station 105 -a.
“According to some aspects of the disclosure, base station 105a may assign resources (e.g. resource elements (REs),) to one or several UEs 115 so that beam recovery is not restricted to the NRSS associated resources within the control area. The configuration can be sent via RRC signaling or a system information broadcast in some cases. L1/L2 signaling can be used to enable or disable the configuration. UE 115 a can be triggered in certain cases to access additional resources during beam recovery (e.g. through a resource grant by base station 105 -a). The resources for beam recovery are not subject to contention. UE 115 may therefore access the designated resources after they have been granted by base station 105. The configuration could be unique to UE 115 or a group of UEs 115. Sometimes, the configuration can be traffic dependent. E.g. Base station 105-a might configure a group of UEs 115 that have uplink resources that are more frequent to reduce beam recovery delays. Alternatively, in a low traffic scenario (e.g. when UE 115 has a small amount of data to send), the SR resources within the RACH area may suffice. This is because delays might be easier to tolerate in such a situation. Base station 105-a might configure UEs 115 with a high SNR to use any beam from the uplink for beam recovery.
“In some cases, basestation 105-a might specify a SFN or periodicity, REs, and a slot, mini-slot, or SFI. for the uplink resources. The number of UEs 115 using the uplink beam can affect the configuration of the REs per beam. Base station 105-a might specify a maximum number of beam recovery requests that UE 115 a will make. This may be based on the number or other conditions (e.g. a timer). Base station 105 may in some cases configure higher frequency or longer time resources for certain beams than other beams, e.g. to support a larger payload. The configured resources could also be located in another region than the RACH.
“Base station (105-a) may indicate a relationship between downlink beacons and uplink resources. Base station 105-a could provide equivalent uplink resources to each downlink beam. In certain cases, downlink beams can be based on one or more of the following: an NR-SS or an MRS or a CSIRS (e.g., a periodic CSIRS). The present disclosure may allow for the association of respective reference signals with their own dedicated uplink resources. The frequency of the dedicated resources could be determined by the periodicity the associated reference signal. The periodicity of uplink resources can be greater, equal, or lower than that of associated reference signals. For example, the periodicity for uplink resources could be multiples (e.g., an int multiple) of the associated signal. There are many possible relationships between periodicities of reference signal and uplink resource that are not mentioned herein, including those that are based on a relationship between uplink resources or one or more reference signals. Sometimes, measurement reference signals, such as MRS or CSI-RS, may be transmitted more often than the NRSS.
“UE 115-a can determine beam failure on one of the active beams and use the configured resource to send a beam recover message. UE 115 may, for example, monitor a number of reference signals in order to determine if a beam loss has occurred. If so, the beam recovery message will be transmitted. The beam recovery message can be sent via one or more uplink resources, and/or in one/more beam directions. The beam recovery message could contain reference signals measurements from one or several beams, or one or two cells. These measurements can be made before or after beam failure is detected in some cases. In some cases, the frequency of the dedicated resources may be less than that of the reference signals. UE 115a can continue to measure reference signals while it waits for the dedicated resources. The reference signals could include NR-SS and MRS. The measurement results can include an indication of RSRQ, CQI and PMI as well as rank indicator (RI) in some cases. In some cases, UE 115a may provide direction information. For example, a mobility condition that includes UE 115a’s direction, a distance to base station 105a, and an orientation of UE 115a. UE panel information (e.g. number of antennas or arrays at UE 115?a).
“UE 115-a can specify a downlink beacon identifier in some cases (e.g., explicit and/or implicitly using appropriately mapped uplink resources to the given downlink beam). UE 115 may, for example, identify one or more candidate beams within the beam recovery message (e.g. using a beam identifier). This information can be used to recover beams. In these cases, the beam message may also include information about the signal quality of the candidate beams (e.g., using reference signals measured on candidate beams). UE 115-a can also send information in the beam recover request to indicate whether a candidate beam is present based on measurements.
“Base station 105 may receive one or several beam recovery messages from UE 115a. Base station 105 may receive a subset or all of the beam recovery messages. In some cases, multiple UEs 115 could transmit simultaneously over the same resources. Base station 105 may distinguish transmissions based upon a scrambling code (e.g. which may be based in a cell radio network temporary identifier C-RNTI for RRC-connected UEs 115). Base station 105 may reply with a confirmation that UE 115 has indicated a candidate beam or signal a different beam to be recovered. Base station 105 may choose the beam based on the measurement report in the beam recovery message. Base station 105-a might choose to use a different beam (e.g. a refined beam) if the measurement message indicates that UE 115 can use the same receive beam in order to receive the other beam. Base station 105 may choose a transmit beam based on uplink measurements at base station 95-a. A PDCCH sent to UE 115a could indicate that there is an additional reference signal for beam refinement. Other examples may indicate that a beam is not available for beam recovery.
“FIG. “FIG. A UE 115 may use the resource grid 300 as described in FIGS. 1. and 2. Resource grid 300 can be associated with a beam pair between a serving station 105 (not illustrated) and UE 115?b. For the sake of simplicity, some aspects of resource grid 300 were simplified. The arrangement and frequency of the resources below might differ from the ones shown in FIG. 3.”
“Resource grid 300 could include a subset of resources (305-a) and another subset (305-b) within a given system bandwidth. The subcarriers 310 may be transmitted over multiple symbol periods 315 (e.g. OFDM symbols). An RE is a block that spans one symbol period and one subcarrier (310). Alternativly, each block could span a group subcarriers 315 and one subframe (e.g. a TTI), so that each block can be called a resource block (RB). The units of frequency or time in the example are arbitrary and may not be used for any other purpose than to explain. The first subset 305-a could be an example control resource (i.e. resources over which control channel information can be transmitted). The first subset of resources (305-a) may include PUCCH or physical RACH transmissions (PRACH), from one or more UES 115. These channels may also be used to transmit the beam recovery message. The first subset of resources 305a could contain RACH resources 325 or SR resources 320. RACH resources 325 or SR resources 320 can be multiplexed in some cases so that they overlap in frequency or time.
“The second subset 305-b of resources may represent resources within a data area of the system bandwidth. The bandwidth of the second subset 305-b of resources may be greater than the bandwidth of the first subset 305-a. In certain cases, resources 305b could be used to carry PUSCH transmissions.
“UE 115-b might be able communicate with a base station 105 in some cases over multiple active beams (e.g. active beams 330 or 335 in this example). Each active beam can have an associated signal quality. In some cases, UE 115b may prefer to communicate with the serving station 105 over a stronger beam (e.g. active beam 330 which has comparatively higher SNR than other active beams). As shown in FIG. 3, each active beam 330 and 335 could be considered a downlink receiver beam. 2. Each active beam 330, 335 can be used to receive one of the reference signals (e.g. NR-SS or MRS), From the base station 105. UE 115b may monitor the reference signals in respective active beams 330, 335, (e.g. to detect a beam loss).
“Active beam 330 could experience a beam failure in some cases (e.g. signal blockage, movement UE 115b, etc.). UE 115b might not receive any reference signals from active beam 330. Sometimes, the UE 115b may try to report beam failure to the base station 105 using SR resource 320 or RACH resource 325. This means that each active beam 330, 335 might have an associated set SR resources 320 or RACH resources 325, over which beam recovery information can be transmitted. RACH resources 325 and SR resources 320 may not be found in resource grid 300. These resources could also be contention-based resources. UE 115b might not be able access them when they are available.
“In some cases, a basestation 105 may also or alternatively create dedicated resources within the second set of resources 305b to be used for beam recovery information. The dedicated resources can be mapped to specific reference signal and/or active beams 330, 335 in some cases. Active beam 330, for example, may be carrying one or more of NR?SS, MRS and CSI?RS. Each reference signal may have its own set of resources that can be used to relay beam failure information. One or more of these signal may have shared resources. UE 115b could be used to report NRSS failure of active beacon 330 using SR resources 320 and MRS failure active beam 330 using dedicated resources 340a. CSI-RS failure active beam 330 using dedicated resources 340b. It is possible to map other reference signals for the downlink active beam 333. An MRS/CSI-RS or NR-SS may be transmitted more often than an NRSS in some cases. Sometimes, the associated reference signals may be transmitted less often than the MRS and/or CSI-RS.
“Additionally, or alternatively different sets of resources can be reserved for beam failure recover requests for different beams. One or more dedicated uplink resource 345 could be used to transmit beam recovery information to active beam 335, in addition to the dedicated uplink resource 340 to active beam 330. Sometimes, dedicated uplink resources 345 and 340 may be used over the same blocks of resource, but they should be distinguished because active beams 335 and 330 may cover different directions. This frequency reuse is not possible with RACH resources 325. RACH resources 325 can be distributed in many directions. Multiple UEs 115 can transmit using a set of dedicated uplink resource 340, 345 in some cases. Each UE 115 could be associated with a different CRNTI so that each UE 115 can scramble transmissions over dedicated uplink resources 340 and 345 according to respective C-RNTIs. Multiplexing may not work with RACH resources 325. However, UEs 115 could use one or more of the same identifiers.
“In some cases the dedicated uplink resources 340 and 345 may be set to occur more often than the RACH resources 325, or the SR resource 320. The dedicated uplink resources 345, 340 may also support higher data rates, such as a longer duration, higher bandwidth, higher modulation, and coding schemes (MCS), or other options. The RACH resources 325 and the SR resources 320 are both lower than these dedicated uplink resources. The dedicated uplink resources 345 and 340 may be able carry additional beam recovery information as shown in FIG. 2. ”
“In certain cases, UE 115b may attempt to transmit a beam-recovery message over the SR resource 320. In certain cases, UE 115b might not be able access the SR resources 320. It may then attempt to access RACH 325. UE 115b may be given a configuration (e.g. via RRC signaling), specifying which resources will be used for beam recovery messages (e.g. which frequency and time they may be used), and UE 115b may decide to use the uplink resources 340 and 345. UE 115b can be triggered (e.g. via L1/L2 signals) to access these uplink resources 340 and 345.
“FIG. “FIG. The 400 process includes a UE 115c and a base station 105b. Each of these devices may be examples of the corresponding devices discussed above with reference to FIGS. 1. through 3. The process flow 400 could be an example of signaling uplink resources that are used to transmit a beam recovery message.
“At 405, UE 115 c and base station 105 b may establish a communication by using one or more active beams. Base station 105b at 410 may detect a communication parameter that is associated with one or several active beams. This could be used to identify the base station 105b communicating with UE 115c. Base station 105-b might identify a traffic level that is associated with UE 115 -c in some cases (e.g. a group of UEs 115). Base station 105-b could also identify an SNR associated to the communication with UE 115 c established at 405. Base station 105-b might identify a payload in some cases associated with uplink transmissions from UE 115 -c.
“At 415 the base station (105-b) may transmit (e.g. UE 115 -c may receive), a configuration for uplink beam resource recovery resources. Sometimes, the uplink beam resources are associated with different regions of resources than those that are used for transmission of random access messages (e.g. for RACH messages). Base station 105-b might transmit the configuration in some cases as part of RRC signaling. The configuration can also be transmitted via a system information broadcast.
“UE 115-c could receive the configuration either as part RRC signaling, or as part the system information broadcasted from base station 105 -b. The configuration of the uplink resource depends in some cases on one or more communication parameters at 410. The uplink resource configuration could be based on identified traffic levels and transmitted to one or more UEs 115. Alternately, the uplink configuration can be specific to UE 115c based upon the SNR associated UE 115c. The configuration may indicate additional beam recovery resources that are available for one or more beam-recovery messages, based at minimum on the identified payload. Sometimes, the configuration might indicate a set beams for each one or more beam-recovery messages.
Base station 105-b might identify one or more reference signal associated with a set downlink beams. This may allow it to identify a mapping between the uplink beam recovery resources, and the downlink beams based upon the reference signals. Base station 105b may indicate the mapping in the configuration at 415. Sometimes, the configuration may include an SFN corresponding the uplink beacon recovery resources, an SI corresponding the uplink beech recovery resources and a periodicity corresponding the uplinkbeam recovery resources.
“At 420 base station 105b may enable or disable the uplink beam recover resources for transmission of beam recovery messages. Sometimes, L1/L2 signaling may be used to indicate whether the resource is enabled or disabled. UE 115c at 425 may indicate a beam failure in one or more active beams that were used to establish the communication at 405
“At 430, UE 115 -c may optionally measure various signals received at base station 105 -b. These measurements can be made before or after the beam failure at 425 is identified. In certain cases, UE 115c may measure a set reference signals. One or more active beams at 405 may be used to associate the set of reference signals. The set of reference signals may include a synchronization signal or a MRS, a CSI RS, or a combination thereof. UE 115 c can determine a mobility condition that is associated with UE 115 c. This includes a direction of UE 115 c relative to base stations 105-b and UE 115 c’s orientation relative to base stations 105-b. It also may indicate a distance from base station 105 -b or a combination of both. UE 115 c can identify information about antenna arrays that correspond to one or more of the antenna arrays at UE 115 c. Sometimes, information about antenna arrays includes information about several antenna arrays located at UE 115.c.
“At 435, UE 115 -c may transmit (e.g. and base station 105 -b may receive), a beam recovery message according the received configuration using uplink beam recovery resources based upon the beam failure identified as 425. A beam failure recovery request may be included in the beam recovery message. Base station 105-b might receive one or more beam message on a set resources in one or several receive beam directions. In certain cases, UE 115 c may transmit the beam message on one or several resources in one or multiple beam directions. Aspects allow the beam recovery message to be transmitted using at most one of the plurality beams specified in the configuration at 415 (e.g. based on an SNR associated UE 115c). UE 115c may transmit, depending on the configuration at 415, an SR from base station 105b using uplink beam recovery resources. UE 115c may transmit the beam message in some cases based on the indication received at 415 that enables or disables use of uplink beam resources to transmission of the beam message.
“In some cases, the beam recovery message might include a measurement report that is based on measurements taken at 430. A measurement report could include, for instance, an RSRQ or CQI, PMI or rank (e.g. an RI). The beam recovery message can also include an indication of mobility conditions at 430. In some cases, the beam recovery message might include information about the antenna array information at 430. One example is that UE 115c could determine the identity of one or several downlink beams at base station 105b. This information may be included in the beam recovery message.
“Based on the beam recovery message at 435, base station 105b may determine the transmit beam direction at 440. Base station 105-b can perform measurements on uplink signal strength over one or more active beams to determine the transmit beam direction. Base station 105-b at 445 may transmit (e.g. and UE115-c may get) a message as a response to the transmitted beam recover message. The message may include an indication of one, or more, reference signals for beam refinement. This message can be transmitted to UE 115c in some cases using the transmit beam direction at 440.
“FIG. “FIG.5” 5 depicts a block diagram 500 for a wireless device 505 which supports uplink resources to beam recovery in accordance the various aspects of this disclosure. The wireless device 505 could be an example of aspects of a UE 115, as shown in FIG. 1. wireless device 505 could include receiver 510 and UE beam recovery manger 515. These components can be connected to one another, e.g. via one or more busses.
“Receiver510 may receive packets, user information, or control information as a result of various information channels (e.g. control channels, data channels and information about uplink resources for beam recuperation, etc.). The information may be transmitted to other parts of the device. One example of the aspects of transceiver 835 that may be used in receiver 510 is shown in FIG. 8.”
“UE beam Recovery Manager 515” may be an example of aspects in the UE beam Recovery Manager 815, as described with reference to FIG. 8. UE beam recovery manger 515 and/or some of its subcomponents can be implemented in hardware, software, firmware, or any combination thereof. The functions of the UE beam restoration manager 515, and/or at most some of its subcomponents, may be implemented in software by a processor. This includes a general-purpose CPU, a digital signal process (DSP), an app-specific integrated circuit, an ASIC, a field-programmable gate array, (FPGA), or any other programmable device.
“The UE beam recover manager 515 and/or some of its subcomponents can be physically located in various positions. Some functions may even be distributed so that they are executed at different locations by one or more devices. In accordance with different aspects of the disclosure, UE beam Recovery Manager 515 and/or at most some of its subcomponents could be a distinct component. In some cases, UE beam Recovery Manager 515 and/or at most one of its subcomponents can be combined with other hardware components such as an I/O, transceiver, network server, another computing device, or a combination of these components in accordance to various aspects of this disclosure.
“UE beam Recovery Manager 515” may receive a configuration to beam recovery resources. It will identify a beam loss of one or more active beams that are used to communicate to a base station 105 and send, according to the received configuration to the base station 105, a beam restoration message using the beam recovery resource based on the identified failure.
“Transmitter 520 can transmit signals that are generated by other parts of the device. The transmitter 520 can be colocated with the receiver 510 of a transceiver modules. The transmitter 520 could be one example of the transceiver 835 aspects described in FIG. 8. The transmitter 520 can include one antenna or a group of antennas.
“FIG. “FIG. 6” shows a block diagram 600 for a wireless device 605 which supports uplink resources to beam recovery in accordance the various aspects of this disclosure. The wireless device 605 could be one example of aspects of a wireless 505 or a UE 115, as shown in FIGS. 1. and 5. wireless devices 605 could include receiver 610 and UE beam recovery managers 615. The transmitter 620 may also be included in wireless device 605. These components can be connected to one another, e.g. via one or more busses.
“Receiver610 may receive packets, user information, or control information as a result of various information channels (e.g. control channels, data channels and information about uplink resources for beam recuperation, etc.). The information may be transmitted to other parts of the device. A representative example of transceiver 835 aspects may be the receiver 610, which is shown in FIG. 8.”
“UE beam Recovery Manager 615” may be an example of aspects in the UE beam Recovery Manager 815, as described with reference to FIG. 8. UE beam recovery manger 615 and/or some of its subcomponents can be implemented in hardware, software, firmware, or any combination thereof. The functions of the UE beam restoration manager 615, and/or at most some of its subcomponents, may be implemented in software by a processor. This includes a general-purpose CPU, a digital signal process (DSP), an app-specific integrated circuit, an ASIC, a field-programmable gate array, (FPGA), or any other programmable device.
“The UE beam recover manager 615 and/or some of its subcomponents can be physically located in various positions. Some functions may even be distributed so that they are executed at different locations by one or more devices. In accordance with different aspects of the disclosure, UE beam Recovery Manager 615 and/or at most some of its subcomponents could be a distinct component. In some cases, UE beam management manager 615 or at least one of its subcomponents can be combined with other hardware components such as an I/O, transceiver, network server, another computing device, or a combination of these components according to various aspects of this disclosure. UE beam management manager 615 could also include resource configuration component 625 and beam failure component 630.
“Resource configuration element 625 may be able to receive a configuration for beam-recovery resources. Receiving the configuration for beam recovery resources may be done as part RRC signaling from base station105 or as part a system information broadcast from base station105. The configuration might include a UE-specific configuration to recover beam resources. Sometimes, the configuration may indicate a set beams that will transmit a beam recovery message. This indication could be based on the UE 115’s SNR. The configuration might include an indication of the SFN corresponding the beam recover resources, an SFI that corresponds to the beam resources, a periodicity that corresponds to the beam resources, one or more REs that correspond to the beam resources, or a combination of these. Sometimes, the beam recovery resources might occupy a different region than the second region of resources used for transmission of random access messages (e.g., RACH). The configuration might indicate a mapping between the downlink beam from base station 105, and the beam recovery resource.
“Beam failure component (630) may detect a beam failure in one or more active beams that are used to communicate with base station 105. UE beam recovery manager 635 may transmit, based on the received configuration, a beam loss message to base station 105. In certain cases, UE beam message manager 635 might receive an indication that allows the beam resources to be used for transmission of the beam message. The indication is used for transmitting the beam message. UE beam recovery manager 635 could also receive an indication disallowing the beam recovery resources to transmit the beam message. Sending the beam recovery message from the base station to 105 might include sending the message using at most one of the beams identified by the base station. Sometimes, the beam recovery message can be transmitted to the base station at 105 by transmitting it on one or more resources using one or more beam directions.
“Transmitter 620 could transmit signals that are generated by other parts of the device. The transmitter 620 could be colocated with the receiver 610 of a transceiver modules. The transmitter 620 could be one example of aspects of transceiver 835, as shown in FIG. 8. The transmitter 620 can include one antenna or a group of antennas.
“FIG. “FIG. 7” shows a block diagram 700 for a UE beam recover manager 715, which supports uplink resources to beam recovery in accordance the various aspects of this disclosure. The UE bea recovery manager 715 could represent one of the UE beam management managers 515, 615 or 815 as described in FIGS. 5, 6, and 8 5, 6, and 8. The functions of the UE beam restoration manager 715, and/or at most some of its subcomponents, may be implemented in software by a processor. This includes a general-purpose CPU, a digital signal process (DSP), an app-specific integrated circuit, an ASIC, a field-programmable gate array, (FPGA), or other programmable device.
“The UE beam recover manager 715 and/or some of its subcomponents can be physically located in various positions. Some functions may even be distributed so that they are executed at different locations by one or more devices. In accordance with different aspects of the disclosure, UE beam recover manager 715 and/or some of its subcomponents could be a distinct component. UE beam recovery manger 715, at least one of its subcomponents, and/or some of them, may be combined with other hardware components. This includes, but is not limited to, an I/O component, a transmitter, a network server or another computing device. Or a combination of these components according to various aspects of this disclosure. The UE beam Recovery Manager 715 could include resource configuration component 720 and beam failure component 725. It also may contain scheduling request component 740, beam refinement part 735, scheduling request piece 740, signal measurement portion 745, mobility condition component 750 and antenna information component 755. It also includes downlink beam component 760. These modules can communicate with each other directly or indirectly (e.g. via one or several buses).
“Resource configuration element 720 may be able to receive a configuration for beam-recovery resources. Receiving the configuration for beam recovery resources may be done as part RRC signaling from base station105 or as part a system information broadcast from base station105. The configuration might include a UE-specific configuration to recover beam resources. Sometimes, the configuration may indicate a set beams that will transmit a beam recovery message. This indication could be based on the UE 115’s SNR. The configuration might include an indication of the SFN corresponding the beam recover resources, an SFI that corresponds to the beam resources, a periodicity that corresponds to the beam resources, one or more REs that correspond to the beam resources, or a combination of these. Sometimes, the beam recovery resources might occupy a different region than the second region of resources used for transmission of random access messages (e.g., RACH). The configuration might indicate a mapping between the downlink beam from base station 105, and the beam recovery resource.
“Beam failure component 725 might identify a beam loss of one or more active beams that are used to communicate with base station 105. UE beam recovery manager 730 can transmit, based on the received configuration, a beam loss message to base station 105. Sometimes, UE beam message manager 730 might receive an indication that allows the beam resources to be used for transmission of the beam message. The indication is used in transmitting the beam message. UE beam recovery manager 730 could also receive an indication disallowing the beam recovery resources to transmit the beam message. Sending the beam recovery message from the base station to 105 might include sending the message using at most one of the beams identified by the base station. Sometimes, the beam recovery message can be transmitted to the base station at 105 by transmitting it on one or more resources using one or more beam directions.
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