Communications – Alexander Maltsev, Vadim Sergeyev, Alexei Davydov, Ali Sadri, Roman Maslennikov, Alexey Khoryaev, TAHOE RESEARCH, LTD.
Abstract for “Wireless communication system that communicates using different beamwidths
This document describes communication signals that use a first frequency band and a second frequency bandwidth in a wireless network. The first frequency band can be associated with first beamwidth, while the second frequency bands may be associated to a second beamwidth. An apparatus could include receiver circuitry that is arranged to receive first signals from a frequency band that has a first beamwidth and then second signals from a frequency band with a second beamwidth. The first signals may contain a frame sync parameter, and the second signals comprise frame alignment signals. Further, the apparatus may include processor circuitry that is coupled to the receiver. This processor circuitry will activate or deactivate receiver circuitry in order to receive frame alignment signals. It will be based on the frame sync parameter. Other embodiments are possible to be described and/or claimed.
Background for “Wireless communication system that communicates using different beamwidths
“The current state of wireless communication means that more communication devices can wirelessly communicate with one another. There are many types of communication devices available, including personal computers, mobile and desktop computers, displays, storage devices as well as handheld devices. Many of these devices come packaged with a purpose. Devices such as set-top boxes and personal digital assistants (PDAs), pagers, text messages, game devices, wireless mobile phones, and web tablets are all available in?purpose? packaging. These devices can communicate with one another in a variety of wireless environments, including wireless wide area networks and wireless metropolitan area networks. Wireless local area networks (WLANs), wireless personal area network (WPANs), Global System for Mobile Communications networks, code division multiple accessibility (CDMA), and others.
“The increasing demand for high-throughput applications like video streaming, real time collaboration, video content downloading, and the like places stringent requirements on wireless communication systems to deliver better, faster and cheaper communications systems. Unlicensed frequency bands like 2.4 GHz (Industrial, Scientific, Medical, (ISM), and 5.0 GHz [Universal National Information Infrastructure, (UNII]) have been used for communications as low as a few hundred Mbps in recent years. To achieve these bit rates, relatively complex modulation techniques such as multiple-input/multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) have been proposed to the Institute of Electrical and Electronics Engineers (IEEE). These bands have become very popular due to their popularity. This can cause significant interference for those who use them.
IEEE committees are now looking into communications at higher frequencies, such as frequencies greater than 20 GHz, in order to provide interference-limited Gbps communications. FIG. FIG.
“The following detailed description refers to the accompanying drawings, which form a portion hereof, wherein like numerals designate similar parts throughout. It also shows illustration embodiments in the subject matter of this disclosure. Other embodiments can be used and logical or structural changes can be made without departing completely from the scope. The following description should not be taken as a limitation. Instead, the appended claims (or equivalents) define the scope of embodiments according to the present disclosure.
“Various operations can be described as discrete operations in turn in a way that may help in understanding embodiments in the present disclosure. However, the order in which they are described should not be taken to mean that they are order dependent.”
“The description could use phrases like “in one embodiment”,? or ?in various embodiments,? Each term may refer to one or more embodiments. The terms “comprising”,??, and “including”,? may also be used. ?including,? ?having,? ?having,? and similar terms are used in relation to embodiments of this disclosure.
“Various embodiments of this disclosure provide methods and systems that allow a communication device to communicate with other devices in a wireless network using a different frequency band. The embodiments may associate the first frequency band with a first beamwidth and the second frequency band with a second beamwidth. However, the first beamwidth may be greater than the second beamwidth. While the description below describes two frequency bands, alternative embodiments may employ more than one.
“In different embodiments, the first frequency range may be used to transmit (i.e. receive and transmit) first signals. This includes initial communication of first signals that contain signals and/or control information to coarsely configure other communication devices in order to wirelessly communicate with the device. The second frequency band may be used for the transmission of second signals between devices. The second signals may also include control information and signals that allow for finer configurations of other communication devices in order to wirelessly communicate with the communication devices.
“In certain embodiments, the initial signals may be modified for signal detection, initial beam formation, and/or initial carriers frequency offset (CFO), estimation to allow subsequent communication with the second frequency band. The second signals communicating through the second frequency band can be modified to provide more precise beam formation that complements the initial beam forming, and/or signals that can be used for fine CFO estimates that may augment the initial CFO estimate. The second signals can be used to facilitate the timing synchronization between other communication devices and the communication device. As mentioned, the second signals communicating using the second band may facilitate further communication using that band to allow for the transmission of third signals using the same frequency band. The second frequency band can be used to communicate third signals. These may include data related to video streaming, realtime or non-realtime collaboration and video content download.
“Variable approaches can be used in different embodiments to communicate through the first frequency band associated the first beamwidth (herein:?first frequency range?). The second frequency band associated to the second beamwidth (herein “second frequency band”) In some cases, communication using the first frequency range may result in communication using a low frequency band, such as the bands below about 20GHz, while communication using second frequency bands may result in communication using a higher frequency band, such as the bands above 20GHz. There are many alternative ways to use different antenna systems, including multi-element and/or multiple antennas. These antenna systems can be used in communication using both the first and second frequency bands.
The first frequency band could be lower than the second. These embodiments may use the 2.4GHz ISM band, the 5.0GHz UNII channel, or any other band less that about 20GHz. The second frequency band could be a higher frequency range, such as the band greater than 20 GHz or one centered in the 59-62 GHz spectrum. For the purposes of this description, communication using the lower frequency band is referred as out-of band (OOB) communications while communicating using higher frequency bands may be called in-band communications. Other frequency bands can also be used in alternative embodiments as the first and/or second frequency bands. The 20 GHz mark may not be the delimiter between the lower frequency band and higher frequency band. Other alternative embodiments allow the first and second frequency bands to be centered at the exact same frequencies, but can be associated with different beamwidths using antennas with different aperture sizes.
The communication device may use the first frequency band to communicate with other devices in the wireless network. OOB control information signals, or simply?first controls signals? are examples. To facilitate data communication using this second frequency band. The first control signals could contain?signals? and/or ?control information? To facilitate the initial or coarse beamforming and CFO estimation, timing syncization, and other functions of the device or other communication devices. The second frequency band may be used by the communication device to transmit or receive data to and from other devices in the wireless network. To facilitate data communication, the second frequency band may be used. The second control signal may include signals and control information that facilitate fine beamforming and CFO estimation. It also allows for timing synchronization and other functions of the communication device. Signals for tracking the beamforming, CFO and timing can be included in the next data or data signals that are to be transmitted (i.e. received and/or transmitted) using the second frequency range. There may also be signals for data such as data related to video streaming, realtime collaboration, video content downloading, audio and/or text content download/upload, and so on.
“To appreciate the various aspects of the embodiments discussed herein, we will discuss the characteristics of frequency bands with relatively broad beamwidths and those with narrow beamwidths. The characteristics of different types of antennas, including omnidirectional and directed antennas, will be discussed. A discussion will be included about the effects of using a lower frequency band as opposed to one with higher frequencies.
“This discussion starts with a brief description about beamwidths. A beamwidth refers to a spatial characteristic that is typically associated with dishes or antennas. An antenna’s beamwidth can be calculated by dividing the antenna aperture size by the wavelength of the signals to transmit (or receive). If the wavelengths of the signals being transmitted or received are constant, then the beamwidth will be smaller the larger the aperture. Alternately, the beamwidth can be reduced by transmitting or receiving signals with shorter wavelengths (i.e. higher frequency), while keeping the aperture size constant. Different beamwidths can result when antennas with similar aperture sizes transmit signals from different frequency bands. The above discussion is about the relationship between aperture size, beamwidth and frequency bands. However, multi-element antennas can be used to control the beamwidth. In this case, aperture size may not matter as much as the signal to be transmitted. Multi-element antennas may be used to transmit or receive signals with different beamwidths.
An antenna with a narrow aperture such as an omnidirectional antenna is a good option to achieve a broad beamwidth. An antenna with a larger aperture, such a directional antenna is an alternative to or in addition to using a high frequency band to achieve a narrower beamwidth. Alternately, an antenna can provide different beamwidths by changing the frequency bands (i.e. higher or lower frequency band) of the signals that are to be transmitted and/or receive. Multi-element antennas can be used to provide different beamwidths in other frequencies, as mentioned above. One set of multi-element antennas can be adaptively controlled by special protocols or procedures to provide beam directions and beam shapes. A single set of multi-element antennas can be used to provide multiple frequency bands with varying beamwidths. The phrase “antenna” is used in the following description. The phrase “antenna” could refer to either a single or multi-element antenna.
“Referring to FIG. 2 Comparing the beamwidths for different frequency bands using antennas with approximately the same aperture size. One of the benefits of using lower frequency bands, such as the ISM band at 2.4GHz or the UNII band at 5.0GHz, to communicate in a wireless network, is the possibility that beamwidths associated with lower frequency bands (e.g. bands greater than 20GHz) may be greater. The higher beamwidth will allow signals to reach more devices within the wireless network because of its greater reach. The downside to using a lower frequency band because of its greater beamwidth is that there is more chance of interception and interference due to the wider wedge.
“Compared to lower frequency bands, higher frequency bands can be used for communication in a wireless network. This may lead to a narrower beamwidth as previously described. There may be less interference as a result. Aside from the narrower beamwidth, a higher frequency range may have another property: if an even higher frequency band (such the 24 or 60 GHz bands) is used, there could be additional attenuation due to distance, such as oxygen absorption. FIG. 2 shows that a higher frequency band, such as the 60 GHz band, may have a smaller beamwidth or a shorter range. Or?reach? You can reach more remote devices than those operating in a lower frequency band (e.g. 2.4 and 5.0GHz bands). Devices operating in the 60GHz band, instead of the 2.4 and 5.0GHz bands, may have lower interference risks from remote devices.
A higher frequency band is a better choice for wireless communication. This is because it allows more signal bandwidth (as more spectrum is available at higher frequencies), which can result in greater data throughput. The use of a larger bandwidth can decrease the power spectrum density of the transmit signal, and possibly decrease reliable communication range due the lower signal-to noise ratio at the receiver.
An omnidirectional antenna can be replaced by a directional antenna if the frequency band is higher for wireless communication. An antenna like this can have its advantages and drawbacks when communicating in a wireless network. One advantage to using a directional antenna is the ability to transmit signals at a higher frequency than an omnidirectional antenna. This allows for less power to be required to receive the same amount of power. The directional antenna may use radio frequency (RF), components that are less efficient and less expensive. This can be significant in certain situations, as the costs of RF parts for higher frequency communications may be much higher.
There may be some drawbacks to communicating with a wireless network that uses a higher frequency band and directional antennas. To register all communication devices within the network, an adaptable or multiple fixed antenna setting may be required. This can be time-consuming. It may also be difficult to synchronize the communication device in a network using protocols like carrier sense multiple acces and collision avoidance (CSMA/CA), or carrier sense multiple accessibility and collision detection (CSMA/CD).
“In accordance to various embodiments, characteristics of frequency bands associatedwith different beamwidths may be combined and used for wireless communication networks in accordance avec various embodiments.
“FIG. “FIG. The network 300 can be WWAN or WMAN, WLAN, WPAN or any other type of wireless network. Communication devices (CDs 302-308 can be set-top boxes (PDAs), desktop computers, laptops, set-top box, set-top computers, personal digital assistants or (PDAs), wireless mobile phones, smart devices, pagers and text messengers, as well as game devices, smart devices, smart appliances and other types of computing or communications devices. One or more of the CDs 302-308 could be a master, or access point. The other CDs can be clients or slave devices. In alternative embodiments, there may be more or less CDs in the network 300. Each CD 302-308 can communicate with other CDs in the network 300 through links 310, which may be bidirectional. The communication between CDs can be done in accordance to standards like 802.11a or 802.11b and any derivatives thereof.
“The present disclosure will be described in detail assuming that network 300 is a WPAN, that CD 302 acts as the access point, and that other CDs 304-308 act as clients devices. In alternative embodiments, network 300 could not contain an access point. In alternative embodiments, the network 300 could be an ad-hoc mesh networking network. In such cases, the access point may not be necessary. Referring to FIG. 3. In some embodiments, at most some client CDs 304-308 can arbitrarily or randomly join/leave the network 300. Client CD 304-308 may associate or authenticate itself each time it enters the network 300 (herein?associate?). The network 300 can be accessed by the client CDs 300 to allow them to?know? the other client CDs 300. The client CD is present in network 300. A client CD 304-308 can associate with the network 300 in certain embodiments by associating to the access point CD 302. In this illustration, client CD304 has just entered network 300 according to reference 312.
“The CD 304 may, upon entering the network 300, associate itself with it (e.g. via access point CD 302). According to various embodiments, the association with network 300 can be achieved using, for instance, a frequency band that has a broad beamwidth. The association signals can be transmitted using a frequency band with a broad beamwidth (herein “first beamwidth”). The authentication signals (e.g. beacons) may be received by CD 304 more easily than the CDs 302, 306 and 308 in network 300. In some embodiments, the first frequency range may be a ISM 2.4GHz, a UniI 5.0GHz, or any other band that is less than 20 GHz. The access point CD 302 can listen for signals in the first frequency band to verify or associate an entry CD 304. The components of CD 304 can then?sleep’ after successfully associating or registering with the network 300. This may be done via any of a variety of authentication and/or association protocols. It may then go into a state of?sleep’ until it receives data transmissions from any other CDs or is ready for data transmission to the network 300 (i.e. to one or more CDs in network 300).
“When client CD 304 is ready for transmit signals to one of the other CDs 302, 306, or 308 in network 300 (including access point CD 302) it may transmit first control signals that include control data using the second frequency band associated to the first beamwidth. The other CDs 302, 306, 308 and 308 in network 300 will be more likely to hear the signals if they use the same frequency band as the first beamwidth. The signals sent by client CD 304 can be heard or received. This could allow for interference to be reduced in the second frequency band as the devices now know the intentions of CD 304 and can delay their transmission for the required time. The signal parameters of the client CD 304’s first control signals may be determined by various CDs 302, 306 and 308 in different embodiments. The signal parameters of the client CD 304 may be determined by the other CDs 302, 306. and 308. This will allow them to determine the signal strength as well as the angle of arrival. The distance between the CDs 302, 306., and 308 and the client CD 304 may be determined by using the CDs 302, 306., and 308 as a guide.
Further, CD 304’s location relative to other CDs (302, 306, or 308) may be determined using other CDs 302, 306. and 308 that are based at most in part on the angle at which the initial signals were received in the first frequency band. These calculations may allow for further communication by using a second frequency band with a narrow beamwidth. The antenna systems used by the other CDs 302.306 and 308 could be correctly configured and/or aligned according to the determinations to facilitate further communication using a second frequency band between CDs 302,306, and 308 and client CD 304.
The first control signals sent through the first frequency band could facilitate communication between CD 304 and other CDs 302, 306. and 308 of network 300. This includes signals and/or control information to allow CD 304 to communicate with other CDs 302, 306. and 308 for coarse configuration. Devices then communicate with each other using a second frequency range that has a narrower beamwidth. In some embodiments, signals for medium access control (MAC), data as associated with CSMA/CA and CSMA/CD may be included in the first control signals. MAC data data will be received by each CD 302, 306, 308, and 308 if they are using the frequency band with the broadest beamwidth. Additional control information may be included in the first control signals, such as signals for initial beam-forming parameters like beam forming coefficients and synchronization parameters. Initial CFO estimation, detection, etc. can also be provided. Some embodiments may include the adaptation of the first control signal to aid beam forming, CFO estimation and/or syncization of other CDs 302, 306. and 308 in certain cases.
“Some embodiments of CDs 302-304 include antenna systems with multi-element antennas. In these cases, the first control signals transmitted in the first frequency band can include signals that facilitate different diversity techniques, such as antenna selection and maximum ratio combing, space-time codes (e.g. Alamouti code), or MIMO techniques.
The second frequency band could be higher than the first. The second frequency band could be an in-band (i.e. greater than 20 GHz), such as the 24-GHz band or a frequency range in the 59-62 GHz spectra. Higher frequency bands, such 20 GHz or higher, can provide more bandwidth than lower frequency bands (e.g. 2.4 GHz or 5.0 GHz). Communication using the second frequency band in various embodiments may be in accordance to a particular technique, such as OFDM and other modulation techniques. In some other embodiments, although the first and second frequency bands may be identical, they may have different beamwidths. This could be achieved by using antennas with different aperture sizes, or an antenna system using multi-element antennas. CD 304 can also be operated in a fallback mode if it is unable or unwilling to communicate with the second frequency bands. This means that communication will only take place via the first frequency band until the second frequency bands become available. For example, if both the receiving and transmitting devices are unable to see each other, then such a fallback mode might be necessary. Each other using the second frequency band.”
To further establish communication, the second control signals can be transmitted using the second frequency range after the first control signal has been transmitted using that frequency band. The second control signals can include signals and/or information to aid fine beam formation, fine CFO estimation, synchronization and so forth. After communication has been established using the second frequency range, signals to track beam forming, CFO estimation, timing, and other information may be sent using this frequency band.
“When client CD304 intends to leave the network 300, as indicated by reference 314, client CD304 may exchange exit information or parameters with network 300 (e.g. access point CD 302) before exiting the network 300. CD 304 can transmit exit information via the first frequency band after exiting the network 300. The reason code may be used to indicate that the application is closed, not authorized to enter the network or has not wanted to communicate with the network.
“FIG. FIG. 4 shows some types of CSMA/CA information that can be transmitted via a first frequency band and a second frequency bandwidth in a wireless network according to various embodiments. Particularly, FIG. FIG. 4 illustrates three nodes A and B communicating with one another in accordance to the CSMA/CA protocol. The first frequency band has a first beamwidth. The second frequency band has a second beamwidth. The first beamwidth may be wider or smaller than the second beamwidth. The embodiments allow the Distributed Coordination Function, DCF, Inter Frame Space, (DIFS), and Contention Window (CW), to be facilitated using one or both of the frequency bands. However, the MAC Protocol Data Unit, (MPDU), and Acknowledge (Ack), may be communicated using either the first or second frequency bands.
“FIG. “FIG. The 500 process may be used by different communication devices. It may start with a communication device entering a network at 504. The communication device may enter the network using a first frequency band (e.g. 2.4 GHz ISM or 5.0 GHz UNII bands) that is associated with a first beamwidth. Once the communication device is done communicating (e.g. transmitting and/or receiving), it may use a first frequency band (e.g. 2.4 GHz ISM band or 5.0 GHz UNII band) associated with a first beamwidth to register with the network at 506.
“On the contrary, if the communication gadget is still communicating with the network (i.e. one or more communication devices in the network), at 508, the device may exchange control signals at the first frequency band with other devices, and then communicate with them using a second frequency bandwidth associated with a second beamwidth of 512. The term “exchange” is not to be confused with the term “interchange”. The term “exchange” as used in this document may refer to a bidirectional or unidirectional exchange. Second frequency bands can be used to transmit second control signals that contain signals and/or control information. This will facilitate further communication with the second frequency band at 514. For example, the second control signals could include signals and/or control information to fine beam forming, fine CFO estimate, and/or syncization. These signals can be used in addition to the first control signals exchanged using first frequency band. This will allow for further communication using second frequency band. After communication is established using the second frequency range, signals carrying different data can be exchanged at 516. Once the communication device is done communicating with other devices in the network, the process 500 can be repeated by returning to 508
“FIG. “FIG. 6” shows portions of a communication device 600. It includes a protocol stack 604 with a variety of layers, including an application layer 606, network layer 608, medium access control layer 610, physical layer 612 and physical (PHY). A controller 602 may be added to the CD 600. This controller is a microcontroller or processor that coordinates the activities of components within the layers of CD 600. Two antennae 614 or 616 may be connected to the components of PHY Layer 612. One antenna 614 could be an omnidirectional antenna, while the other antenna 616 might be a directional one. These embodiments may allow the omnidirectional antenna to transmit or receive signals in a first frequency band associated to a first beamwidth, while the directional antenna can be used to transmit or receive signals in a second frequency range associated with a second beamwidth. The first beamwidth could be higher than the second. In some embodiments, the frequency band in which the antenna is attached may be lower than the frequency band in the second. Alternate embodiments allow only one antenna to be connected to the PHY 612. Other alternative embodiments allow for only one antenna to be coupled to the PHY layer 612.
“The components of the MAC- and PHY layer 610 and 612 (hereinafter referred to as MAC- and PHY layers) may practice various embodiments. PHY layer 612 can be modified to transmit and/or to receive first signals (i.e. first control signals) using one frequency band. This will facilitate the establishment of initial communication using another frequency band. To facilitate further communication using the second band, the PHY layer 612 can be adapted to transmit or receive second signals (i.e. second control signals). The MAC layer 610 may, however, be adapted to select one or both of the frequency bands that the PHY layer 612 uses to transmit and/or to receive the first, second, and/or third signals.
“The omnidirectional antenna 614 can be used to transmit or receive the first signals using the first frequency band. This will facilitate the initial communication between CD 600 and other CDs in a wireless network that uses the second frequency band. The directional antenna 616, on the other hand, may be used to transmit or receive the second and/or third signals using a second frequency band. This communication using the 616 is at least partially established by the first signal transmitted and/or obtained using the 614 omnidirectional antenna. The CD 600 may contain instructions to enable the CD 600 to perform previously mentioned functions.
“FIG. “FIG.7” illustrates a circuitry that transmits and/or receives signals using a first frequency band and a second frequency range in accordance to various embodiments. The circuitry 700 can be used in wireless networks and may include the following: frequency synthesizer 706, antennae 708-714, and transmitter circuitry 702. In alternative embodiments, circuitry 700 could employ any number or combinations of antennas. You should also note that the term “antennae” is not defined. Both?antennae? and?antenas? are synonymous. These terms are used interchangeably in this document.
“The circuitry 700 can operate in various environments, including an Orthogonal Frequency Multi Access (OFMA). Circuitry 700 can include super heterodyne, zero intermediate frequency (ZIF), or other types. The circuitry 700 could be, in some embodiments. It may also include the circuitries described in U.S. Patent Application Ser. No. No.
“The frequency synthesizer 706, according to some embodiments, is a frequency synthesizer which provides both a lower modulation frequency signal 716, and a higher modulation frequency frequency signal 718 to the transmitter circuitry 702 and 704. The first and second modulation frequency signals 716, 718 can be used to modulate or demodulate signals that are to be transmitted and/or received using the first and second frequency bands, respectively. The transmitter circuitry 702 can be coupled to an antenna 708 which may be an omnidirectional or directional antenna. A second antenna 710 may also be connected. The receiver circuitry 704 could be coupled to a third antenna 712, which may be a direction antenna, or a fourth antenna 714, which may be an Omnidirectional antenna.
“The relative CFO of circuitry 700 can be determined by stability in various embodiments. The same oscillator can be used for both the OOB (e.g. first frequency band) as well as the in-band (e.g. second frequency band). The absolute value of CFO might be higher for in-band (second frequency bands) operations.
The OOB operations solve the initial CFO estimation problem and the compensation problem for such systems. The frequency synthesizer 706 uses the same reference clock oscillator, so that the OOB frequency synthesis circuitry as well as the in-band frequency circuitry can be used. The relative CFOs of the signals at OOB frequency as well as in-band frequency could be the same (in ppm). For the OOB signal, it may be possible to make an initial estimate of the receiver’s CFO. After that, a revised estimate could be made and used to compensate for the coarse frequency offset at the in-band frequency. OOB signaling may be used throughout the system to track, for example, timing and carrier frequency offset.
“FIG. “FIG. 8” illustrates a frame format that can be used to communicate in a wireless network with a first frequency band and a second frequency bandwidth in accordance various embodiments. The frame format 800 could be used to represent the signal format to be transmitted or received by a communication device from one end of a wireless network to another. The first frequency band, also known as out-of-band, may be lower than 20 GHz. While the second frequency band, or in-band frequency, may be higher than 20 GHz. You should also note that the bandwidths of higher frequency bands may be greater than those of the lower frequencies. The bandwidth of the second frequency band, which may have a bandwidth between 1-2 GHz and several MHz, may be due to the increased spectra.
“The frame format 800 contains an OOB preamble 802 that is to be communicated via first frequency band. This may be used in signals adapted for signal detection and estimation. The term “preamble” is not to be confused with the term “frame format 800”. The term “preamble” as used in this document is to be interpreted broadly and can refer to any type of data packet, or part of a data packet. In certain embodiments, the OOB preamble could include medium access control data like data relating to CSMA/CA and CSMA/CD.
“The frame format 800 could also include an in-band prepamble 804 or in-band data 806 that can be transmitted using the second frequency band. In-band preamble 804 can be embedded in signals that are better suited for finer timing sync, finer CFO estimation and/or beam forming. Signals for the in-band prepamble 804 can be used to supplement control signals (e.g. initial CFO estimation, initial beam formation, etc.) that are exchanged using the first frequency range. In-band preamble 804 can facilitate communication using the second band to facilitate the communication of in-band data 806. To provide encoded service information, special field symbols can be added to the OOB preamble 802 in order to facilitate communication of the in-band data 806.
CFO is a detailed explanation of certain signals that make up the frame format 800. CFO refers to the difference in carrier frequencies between the receiver and transmitter. CFO estimation can be made more accurate if it is done using the preamble (i.e. preamble signals), of a higher frequency band like the in-band presemble 804, but the OOB preamble802 (i.e. OOB preamble signal) may be used to determine the CFO before finely estimating the CFO using in-band presemble 804. The task of fine CFO estimates may be made easier by including signals for the initial CFO estimation in signals encapsulating the OOB preamble 802.
The in-band prepamble 804 (i.e. in-band signal preamble signals) can be used to finely estimate CFOs. This may complement the OOB preamble 802. The frequency difference between the reference oscillator in a transmitting device and that in the receiving device is called the CFO. The?time scales are determined by the reference oscillators. The transmitting device and receiving device determine the?time scales?. Therefore, the CFO can be calculated as the sum of the frequency difference between the reference oscillators expressed in percent and their absolute values and the carrier frequency expressed in Hertz. CFO estimation schemes are more sensitive to absolute values of the difference between transmitter and receiver carrier frequencies. This is because the CFO values achievable will be higher if the carrier frequency is greater than the receiver’s. CFO estimates may therefore be more accurate if they are made using preamble signals communicating in a higher frequency band, such as an “in-band frequency band”.
“OOB preamble 802 signals may be used to adapt initial beam forming. Initial beam forming, as used herein refers to an initial step in beam forming calculations. It may include preliminary estimations of the angle of arrival for a signal front from a remote transmitter device. This may allow for preliminary adjustments to the antenna system of a receiving device so that it can receive the in-band preamble. This operation can also reduce the search time for the angle of arrival of in-band signals. Initial beam forming, for example, may indicate a sector in which the remote transmitting devices is operating. The initial beam forming might be used to reduce the number sectors that are needed to search for in-band signals.
Fine beam forming can be achieved by using signals that contain the in-band preamble 804. Fine beam forming can refer to the fine tuning of antennas to increase the reception quality of signals, such as in-band signals, which are signals transmitted through the second frequency band. This may involve choosing the best antenna or sector to receive the signal quality metrics. It all depends on the beam-forming algorithm. Fine beam shaping may include complex coefficients or only phase shift values calculations to combine signals from different antennae and different sectors of the sectored antenna.
“The signal containing the OOB preamble 802 could be modified for signal detection. The signals containing OOB preamble 802 could be modified to enable signal detection and indicate to receivers that they are valid. signal. Signals containing OOB preamble can be modified to indicate to receiving devices or devices that it is a signal containing valid? The message may be sent from a network communication device and not just noise or interference. The Federal Communications Commission (FCC), currently allows higher power spectral densities in lower bands (e.g. 2.4 GHz and 5.0 GHz band). Signal detection may be easier in these lower bands due to the higher likelihood that a signal is valid. The lower bands will allow signals to be correctly detected.
“The signals containing the in-band preamble 804 may be modified for fine timing syncization. Fine timing synchronization could refer to a process that locates boundaries of informational symbol within a received signal. The signals of the OOB Preamble 804 have a wider spectrum bandwidth than those of the OOB Preamble signals. These signals could have better correlation properties than, for instance, the OOB Preamble 802. By combining fine timing synchronization signal with the signals of the OOB preamble 802 you can achieve more accurate timing estimation and thus better synchronization.
“Once communication using second frequency band is established, in-band preamble 802 has been communicated and in-band preamble 804. in-band data 806 may be communicated via second frequency band. 8. In-band data 806 could include video streaming, real time collaboration, video content downloading, and so on.
“FIG. “FIG. 8 as shown. The frame format 800 in FIG. The frame format 900 has a time gap 902. The OOB preamble 802 is separated from the higher-frequency portion of the frame. This allows the receiver circuitry to switch between the first frequency bands. It also allows the relaxation processes in the circuitries to complete (see FIG. 7).”
“FIG. 10. depicts another frame format that can be used to communicate in wireless networks using a first frequency band and a second frequency bandwidth in accordance with various embodiments. The frame format 995 is identical to that of FIG. 9. However, the first frequency band can be used after the time gap 902 for tracking and/or sending information as indicated in reference 952. The first frequency band can be used to track beamforming, CFO and timing and/or to send service information, such as channel access signals, in other words. In alternative embodiments, however, the time gap 902 might not be present. You should also note that signals such as pilot signals or training signals may be contained in the OOB portion of the frame format 951
“The earlier embodiments refer to “hard?” Coupled systems that communicate using a first or second frequency band. Communication using the second band results from communication using the first band. Hard coupled systems use the first frequency range to transmit signals (e.g. first control signals) in order to enable subsequent communication using that second frequency band.
“In alternative embodiments, however, ?soft? “Soft” is another possible option. These systems may use two frequencies independently, so signal transmission and reception may overlap with the signal transmission and reception by the same system using the second frequency band. These embodiments may use a lower frequency band, such as 2.4 GHz and 5.0 GHz bands, while the second frequency band could be higher, such as those above 20, GHz (e.g. in-band bands).
The soft coupled system could use the first frequency band for processes that do not require high data throughput rates, such as network entry, bandwidth request, bandwidth grants, scheduling transmissions in a higher frequency band, and transferring feedback information which may include beam forming and power control information. The second higher frequency band, however, may be used to transmit data at high throughput rates.
“FIG. 11. shows frame formats for both the first and second frequency bands of a soft-coupled system. The first frame format 1102 corresponds to a first frequency band of 1100, while the second format 1104 corresponds with a second frequency range of 1101. The frequency band 1100 could be below 20 GHz, while the frequency band 1101 might be above 20 GHz. Frame formats 1102 or 1104 can include respective preambles 110 and 1116, frames PHY headers 1112, 1118 and frame payloads 114 and 1120. Each preamble 1110 and 1116 can be modified to allow frame detection, timing, frequency synchronization, etc., in a manner similar to the hard coupled system. The preambles of the frame formats 1102 or 1104 can be processed separately, but this is not the case with the hard coupled system. Both frame formats 1102 & 1104’s preambles may be embedded in signals that can be used to make coarse and fine estimates of CFO, timing sync, beam forming, etc.
“Both frame formats 1102 or 1104 may contain PHY headers 112 and 1118 to indicate the minimum amount of data in their associated frames payloads 114 and 120. PHY headers 1112 or 1118 can also indicate the modulation/or coding type that will be applied to frame payloads 1114/1120, beam control information, power control information for the payload, as well as other parameters. Frame PHY headers 112 and 1118 can be modulated or coded using, for instance, a predetermined modulation type and beam forming. A predetermined power control may also be applied to the PHY headers 112 and 11.18.
Both frame formats 1102 or 1104 may contain a frame payload 1114 or 1120 to carry payload information. Frame payloads 1114, 1120, and 1104 of both frame formats 1102, 1104 could include additional headers to control the interpretation and meaning of the information in the payload. These sub-headers may include MAC layer headers, which may indicate the source and/or destination addresses.
The frame payload 1114 in the first frame format 1102 could contain channel access control information, such as bandwidth requests or grants. These messages may include special messages for network entry and test signals to measure distance between stations within the network. However, these functions may be carried by preamble 1110 in alternate embodiments. The first frame format 1102 can also include fields to send feedback information back from the destination of a packet to its source. This information could relate to power control, rate control or beam forming control. It may also contain information about channel state information, transmitter and receiver performance indicators like bit error ratio and current transmit power level.
“The second frame format 1104 frame payload 1120 may contain information about higher network protocol layers.”
“The PHY headers 112 and 1118, as well as the frame payloads 114 and 1120, of both the first frame format 1102 and 1104, may contain pilot signals for estimation, tracking, frequency synchronization, timing, and/or frequency sync, and other service tasks.”
“Accessing a wireless channel in a wireless network using 1100 as the first frequency band may be possible due to contention between communication devices (e.g. stations) within the wireless network. To resolve collisions, different techniques can be used. These techniques could include CSMA/CA or CSMA/CD. To reduce collisions, different division techniques can be used. These include code division, frequency or time division, and so on. If contention-based access is used, access to the wireless channel via the first frequency band 1100 can include deterministic mechanisms. Frame exchange sequences in 1100 may include special beacon frames that are periodically transmitted to facilitate frame exchange in 1100. Transmission of frames in the 1100 frequency band may be performed at a substantially random time.
“In contrast with the previous approaches to accessing a wireless channels using the first frequency bands 1100 and 1100, accessing a wireless channel using second frequency band 1101 may not be deterministic. Accessing a wireless channel via the second frequency band may be based upon a schedule that may have been derived from communications using a lower frequency (e.g. first frequency band 1100). This could allow for more efficient use of the high-throughput channel at the higher frequency band 1101. It also reduces the overhead of channel access due to fewer back-offs and retransmissions that can be caused by collisions, such as when accessing random channels.
The first frequency band 1100 could be lower than the second, while the second band 1101 might be higher. The first frequency band 1100 could be associated to a first bandwidth 1106 and the second frequency bands 1101 with a second bandwidth 1108, with the second bandwidth 1108 being higher than the first bandwidth 1106. Some payloads can be transmitted via the first frequency band 1108, while others may be sent using the second frequency channel 1101. Network control messages, for example, are usually short and contain a few tens or more bytes of data. However, higher layer payload information can be several thousand bytes. Network control messages can be sent using the first frequency band 1101 to communicate network information, while higher layer payload information may be sent using the second frequency band 1101.
“FIG. 12. illustrates the transmitter/receiver circuitry for a soft-coupled system for independent dual band communication. Circuitry 1200 could include a transmitter circuitry 1202 or a receiver circuitry 1204. Circuitry 1200 can be coupled to a layer that controls various functions. It may include a transmitter circuitry 1202 and a receiver circuitry 1204. The frequency synthesizer 1206 may be a frequency synthesizer that operates at 2.4/5.0/60GHz. The transmitter and receiver circuitry 1202 (and 1204) are connected to the antennae 1210, 1212 by switches 1214 and 12.16. Alternate embodiments allow the transmitter and receiver circuitry 1202 or 1204 to be connected to any number antennas. The first antenna 1210, and the second antenna 1202, may be adapted to transmit or receive a first and a secondary frequency band. In these cases, the frequency band of the first antenna is lower (e.g. UNII/ISM frequency ranges) than that of the second frequency spectrum (e.g. in-band bands). The MAC layer may control switches 1214 or 1216 to enable selective communication using, for instance, an UNII/ISM frequency range and/or in-band bands.
“FIG. FIG. 13 shows another process 1300 that allows communication between a communication device and a wireless network according to various embodiments. The transmission procedure 1300 could be used to allow a communication device with a neighboring device to communicate with one another and/or a coordination device using a lower frequency (?lower) band. The first frequency band, and the second frequency band (?higher) The second frequency band. The process 1300 could be used for embodiments that are described in conjunction with at least FIGS. 8-10, where communication in a higher band precedes communication in a lower band. Nodes are the name for wireless communication devices. herein. The coordinating device can be found in at least FIG. 19.”
“Block 1302 is the part of the process 1300 that involves listening to the air in higher and lower frequencies to determine at block 1304 whether another communication device or a coordinating device transmits using the higher or lower frequency. For example, the communication device might listen to the air by sensing energy at the receiver antenna in the lower or higher band. The receiver antenna’s energy detection or information from headers (e.g.) may help determine whether another communication device or coordinating device transmits in a higher or lower band. “1118) and/or the contents of frames (e.g., 1122).
“If the communication devices determine that another device transmits, the device can receive signals and/or control information at block 1306, in the higher or lower bands. This will determine how busy a medium of this device will be. A preamble may be included in the received signals and/or control info. It could include data for medium access control, including data for carrier sensor multiple access and collision avoidance (CSMA/CA), or data for carrier sensor multiple access, collision detection (CSMA/CD). A preamble can be a physical layer signal. It may also include a lower band frame with information about channel reservations for higher bands as part of a dual band frame. The ability to receive lower-band communication may enable early detection of transmissions in the higher bands. The communication device might be able detect energy in the higher band if it fails to receive communication from the lower band.
“If the communication device determines, at block 1304, that other communication/coordinating devices are not transmitting in the higher or lower band then the communication device may use a transmission protocol that initiates transmission in the lower band, at block 1308, followed by subsequent transmission in the higher band, at block 1310. When transmitting in a higher band, the communication device may transmit in the lower band.
“FIG. 14. illustrates another process 1400 for communicating using a communication device within a wireless network according to various embodiments. If communication in the higher frequency band is set up in the lower bands and synchronized at physical layer with signals from the lower bands (e.g. As described in FIG. 10).”
“Because the upper and lower bands are synchronized, listening in the air may only be done using the lower band. If the communication device determines that another communication/coordinating device is transmitting in the lower band, at block 1404, then the communication device may receive signals, at block 1406, and/or control information in the lower and/or higher bands to determine how long a medium of the transmitting device will be busy.”
“In an embodiment signals and/or control information, such as headers and/or information related to a transmission schedule are received by the communication devices at block 1406, in lower band. Only in this embodiment, the communication device may use lower band to determine the time slots that are eligible to begin transmission in the lower frequency band at block 1408. If signals or control information are received by a communication device at block 1406, the device may use the higher frequency to decode them. One or more of these embodiments may be implemented by a communication device or system.
“If no other communication devices transmit in the lower frequency band, at block 1404, the communication device can start transmission in that band at block 1408. The communication device can then transmit in the higher band. It may also continue to transmit in the lower band at block 1410. According to the embodiments described with respect to actions 512, 514 and 516 in FIG. 5.”
“FIG. 15. illustrates a search process 1500 performed by a communication device within a wireless network according to various embodiments. The search procedure 1500 may depict operations performed by a communication device that is not aware of the presence of another communication/coordinating device (e.g. “Upon powering on the communication devices.
“At block 1502, the communication device may listen to the air in the lower band to determine, at block 1504, whether other communication/coordinating devices are transmitting in the lower band. The communication device might determine if a signal is being received from another device in the lower frequency band. A signal may be received from a neighboring device. The communication device can use the lower band at block 1506 to communicate with the device. This will determine the capability of the neighboring device in the higher band. If the neighboring device can communicate in the higher frequency, the communication device may initiate an antenna adjustment procedure in the higher frequency as described in connection with FIGS. 16 and 17
“But, if the signal is not received at block 1504, the communication device can continue listening to block 1504. Alternativly, the communication system may transmit a beacon signal at block 1510 in the lower frequency band to let other devices know that the device is present.
“FIG. 16. illustrates an antenna adjustment/link setup procedure 1600 by a communication devices in a wireless network according to various embodiments. The antenna adjustment/link establishment procedure 1600 may be initiated, for example, by one of the communication device or a neighboring communication/coordinating device that indicates a capability to communicate using the higher band (hereinafter ?initiatior?).”
“At block 1602, an initiator may transmit a test message in the higher frequency band to an intended receiver (hereinafter ‘target receiver?). This could include a coordinating and/or communication device. To facilitate adjustments and measurements by the target receiver, the test signal can be transmitted in order to establish a communication channel in the higher frequency band.
“If the target receiver is able to receive the test signal at block 1604, then the link in the higher band at 1606 will be established. The initiator can notify the target receiver (e.g. a peer station and/or a coordination device) that the link is in the higher frequency band.
“If the target receiver doesn’t receive the test signal at block 1604, the initiator or the target receiver can adjust or re-adjust their respective transmitters and receivers (e.g. directional antennas) at blocks 1608 to transmit another test signal in a higher band. The operations at blocks 1602, 1604, 1608 may be repeated until all positions and combinations of antennas have been tested by the target receiver and/or initiator. If the initiator or target node has not tested all positions and combinations of positions at block 1610 then operations 1602, 1604 and 1608 can be repeated until the link is established at block 1606. If both the target node and the initiator have not tested all positions or combinations of positions for their respective antennas, they may fail to establish the link in block 1612. Failure to establish a link can be reported to the coordinating device.
“FIG. 17. illustrates an additional antenna adjustment/link establishment procedure, 1700 by a communication apparatus in a wireless network according to various embodiments. Block 1702 is where the procedure 1700 begins with testing all possible antenna orientation combinations at the target node and the initiator. For example, the initiator may repeatedly transmit a test signal followed by re-positioning of directional transmitters/receivers of the initiator and the target node until all combinations of antenna orientations have been tested.”
“If one of the tested orientations results is a received test signal from the target node hosting target receiver at block 1704 then a link in the higher band at 1706 is established. The initiator can notify the target receiver (e.g. peer station and/or a coordination device) that the link is in the higher frequency band. If none of the test orientations results in a received signal from the target receiver, block 1704 is set. Otherwise, the initiator and target node fail establish a link within the higher band at block 1708. This failure to establish a connection may be reported to the coordinating device.
“FIG. “FIG. 18″ illustrates a signal receipt procedure 1800 by a communication unit in a wireless network according to various embodiments. This procedure may be used to receive signals from a communication device that has synchronized signals in the upper and lower bands (e.g. using a common reference oscillator), as described in connection to FIGS. 8-10.”
“At block 1802, a communications device detects test signal transmissions in the lower frequency band and performs at block 1804, coarse estimation or adjustment of timing/frequency offsets using test signals in the lower frequency band. The block 1806 block performs fine estimation and/or adjustment to the timing and frequency offsets using test signal transmitted in the higher band. Block 1808 is where the communication device receives data payloads using the higher frequency.
“FIG. 19. This illustrates a communication network 1900 that uses a coordinating device 1902 according to various embodiments. One or more communication devices, e.g. 1904, 1906 and 1908, 1910, may be capable of communicating in higher bands than in lower bands using, for instance, transceivers (e.g. TX/RX 0, TX/RX1, TX/RX2, TX/RX 3), according to various embodiments. Communication in higher bands (e.g. Links 1920, 1922. 1924. 1926. 1928. For example, antennas that are substantially Omni-directional can be used to communicate in the lower band (e.g. 1912, 1914 and 1916, 1918).
To manage access to channels in the upper bands, “lower band communication” (e.g. 1914, 1916 and 1918) can be used. A coordinating device 1902 might use the lower band to assign frequency resources (e.g. a time interval), to one or more communication devices (e.g. 1904, 1906. 1908, 1910). This is to determine if neighboring communication devices are capable, available, and/or have sufficient link quality in higher bands to establish communication using that higher band. The assigned time/and/or frequency resource may be used by one or more communication devices to determine the link availability in the higher band. They can then perform link establishment procedures, such as search routines, using the higher bands, and report this information to the coordinating device 1902. To create a schedule or connectivity table for communication devices capable of communicating with each other in the higher band, the coordinating device 1902 may collect link availability from one or more communication devices.
Communication device 1904 might want to communicate with communication devices 1910 in the higher frequency, but may be unable to do so due to a variety of reasons. For example, signal 1934 may block the signal, and 1932 will indicate that the direct link 1930 has been lost. In this case, the communication devices 1904 and 1902 can notify each other. To relay the information, the coordinating device 1902 may use the connectivity schedule/table to organize data transmission between the communication device 1904 and the communication device 1910. This can be done using the higher band communication links 1920-1922, 1924, 1924, 1906, and 1908.
To avoid interference, the coordinating device 1902 can arrange specific time and/or frequency resources to establish higher-band link establishment between communication devices (e.g. 1904, 1906. 1908, 1910). A pair of communication devices might change the positions and directions of their respective antenna systems in a link establishment routine. This could cause significant interference to higher-band transmissions from other communication devices. This interference can be avoided by the coordinating device 1902, which allocates time intervals for higher-band communication between pairs of communication devices.
“The coordinating device 1902 can further organize interference measurements by communication devices using higher bands. The interference measurements can be made by the communication devices within the time period to determine link availability in a higher band. A connectivity table might include information about the interference levels that higher-band links produce on higher-band links, and/or throughput degradation experienced by higher band links.
“Based on interference information, the 1902 coordinating device can calculate/determine a more efficient schedule for transmissions in higher bands by the communication devices. For example, the coordinating device 1902 might allow simultaneous transmissions of links with lower mutual interference or prevent simultaneous transmissions of links with higher mutual interference. The coordinating device 1902 may determine lower and higher mutual interference by comparing the received interference levels and/or corresponding throughput degradation to one another or to a pre-determined threshold interference/degradation level. This scheduling of transmissions may be based on interference information and could increase the aggregate throughput of information within the communication system 1900.
“Using the lower frequency, the coordinating devices 1902 may transmit a transmission plan for communication in the higher bandwidth by the communication device (e.g. 1904, 1906 or 1908, 1910 to the communication devices). For example, the coordinating device 1902 could broadcast a message to notify all the communication devices about the transmission schedule.
“The higher band may be used only by the communication devices, such as 1904, 1906 and 1908 or 1910. An initiating communication device could perform a search procedure in accordance to a transmission schedule from the coordinating device 1902. A search routine could include transmission of preamble/pilot signals in the higher band, and repositioning beams of transceivers. The test signal(s), which may be received by a receiving communication device, can be used to determine if the link quality in the higher frequency band is adequate and/or adjust beam settings to improve the link quality. The initiating communication device may transmit additional test signals using the higher frequency band in order to facilitate carrier frequency offset, timing synchronization and fine beam-forming adjustments in that band. After establishing a link in the higher band between initiating communication devices and receiving communication devices, either one of them may notify the coordinating device 1902 of the newly established link.
“Accordingly to different embodiments, the Coordinating Device 1902 is a communication system having circuitry according to embodiments described, for instance, in FIGS. 6-7. The coordinating device 1902 in an embodiment is an access point (AP), for wireless communication network according to IEEE 802.11 (e.g. Wi-Fi), but it is not limited in this regard. The coordinating device 1902 could also be used to operate according to other wireless technologies.
“The coordinating device 1902 can be connected to a computer network, such as the Internet (e.g. 1950), by a line 1940, such as a wire/optical fiber. Other embodiments allow the coordinating device 1902 to be connected to the computer network (e.g. 1950) via a wireless link (not illustrated). The coordinating device 1902 aims to establish higher band connections with communication devices in the communication network 1900, either directly (e.g. links 1926 and 1928), or through communication devices that act as relays to increase the throughput of the communication network 1900.
“The coordinating device 1902 could include a module that creates the connectivity list based upon received link availability information,/or interference information. A scheduling module can also be used to create a transmission schedule using the connectivity tables and/or associated information.
“Module” is used herein. “Module” may be used to refer to, or be part of, an Application Specific Integrated Circuit or (ASIC), an electronic device that executes one or more software programs or firmware programs.
“FIG. “FIG. 20” illustrates a 2000 process for coordinating communication using a coordinating device (e.g. 1902) in wireless network according to various embodiments. A coordinating device (e.g. 1902) may perform the actions/operations described with respect to the 2000 process. Block 2002 includes transmitting in a lower frequency band, an indication of a frequency resource for a communications device, and identifying one or more neighboring communication devices capable of communicating over the second frequency band.
“The time/frequency resource could, for example include a time period for the communication device use the second frequency bands or another frequency band to identify the one or more neighboring communication devices that can communicate over the second band. An embodiment includes a dedicated frequency channel (e.g. second frequency band, or another frequency interval). If a frequency boundary has been indicated or specified, then the time/frequency resources may include a time period. If a time boundary has been indicated or specified, then the time/frequency resources may include a frequency range such as a channel, band, or one or more subcarriers. This is when OFDM modulation is used.
Summary for “Wireless communication system that communicates using different beamwidths
“The current state of wireless communication means that more communication devices can wirelessly communicate with one another. There are many types of communication devices available, including personal computers, mobile and desktop computers, displays, storage devices as well as handheld devices. Many of these devices come packaged with a purpose. Devices such as set-top boxes and personal digital assistants (PDAs), pagers, text messages, game devices, wireless mobile phones, and web tablets are all available in?purpose? packaging. These devices can communicate with one another in a variety of wireless environments, including wireless wide area networks and wireless metropolitan area networks. Wireless local area networks (WLANs), wireless personal area network (WPANs), Global System for Mobile Communications networks, code division multiple accessibility (CDMA), and others.
“The increasing demand for high-throughput applications like video streaming, real time collaboration, video content downloading, and the like places stringent requirements on wireless communication systems to deliver better, faster and cheaper communications systems. Unlicensed frequency bands like 2.4 GHz (Industrial, Scientific, Medical, (ISM), and 5.0 GHz [Universal National Information Infrastructure, (UNII]) have been used for communications as low as a few hundred Mbps in recent years. To achieve these bit rates, relatively complex modulation techniques such as multiple-input/multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) have been proposed to the Institute of Electrical and Electronics Engineers (IEEE). These bands have become very popular due to their popularity. This can cause significant interference for those who use them.
IEEE committees are now looking into communications at higher frequencies, such as frequencies greater than 20 GHz, in order to provide interference-limited Gbps communications. FIG. FIG.
“The following detailed description refers to the accompanying drawings, which form a portion hereof, wherein like numerals designate similar parts throughout. It also shows illustration embodiments in the subject matter of this disclosure. Other embodiments can be used and logical or structural changes can be made without departing completely from the scope. The following description should not be taken as a limitation. Instead, the appended claims (or equivalents) define the scope of embodiments according to the present disclosure.
“Various operations can be described as discrete operations in turn in a way that may help in understanding embodiments in the present disclosure. However, the order in which they are described should not be taken to mean that they are order dependent.”
“The description could use phrases like “in one embodiment”,? or ?in various embodiments,? Each term may refer to one or more embodiments. The terms “comprising”,??, and “including”,? may also be used. ?including,? ?having,? ?having,? and similar terms are used in relation to embodiments of this disclosure.
“Various embodiments of this disclosure provide methods and systems that allow a communication device to communicate with other devices in a wireless network using a different frequency band. The embodiments may associate the first frequency band with a first beamwidth and the second frequency band with a second beamwidth. However, the first beamwidth may be greater than the second beamwidth. While the description below describes two frequency bands, alternative embodiments may employ more than one.
“In different embodiments, the first frequency range may be used to transmit (i.e. receive and transmit) first signals. This includes initial communication of first signals that contain signals and/or control information to coarsely configure other communication devices in order to wirelessly communicate with the device. The second frequency band may be used for the transmission of second signals between devices. The second signals may also include control information and signals that allow for finer configurations of other communication devices in order to wirelessly communicate with the communication devices.
“In certain embodiments, the initial signals may be modified for signal detection, initial beam formation, and/or initial carriers frequency offset (CFO), estimation to allow subsequent communication with the second frequency band. The second signals communicating through the second frequency band can be modified to provide more precise beam formation that complements the initial beam forming, and/or signals that can be used for fine CFO estimates that may augment the initial CFO estimate. The second signals can be used to facilitate the timing synchronization between other communication devices and the communication device. As mentioned, the second signals communicating using the second band may facilitate further communication using that band to allow for the transmission of third signals using the same frequency band. The second frequency band can be used to communicate third signals. These may include data related to video streaming, realtime or non-realtime collaboration and video content download.
“Variable approaches can be used in different embodiments to communicate through the first frequency band associated the first beamwidth (herein:?first frequency range?). The second frequency band associated to the second beamwidth (herein “second frequency band”) In some cases, communication using the first frequency range may result in communication using a low frequency band, such as the bands below about 20GHz, while communication using second frequency bands may result in communication using a higher frequency band, such as the bands above 20GHz. There are many alternative ways to use different antenna systems, including multi-element and/or multiple antennas. These antenna systems can be used in communication using both the first and second frequency bands.
The first frequency band could be lower than the second. These embodiments may use the 2.4GHz ISM band, the 5.0GHz UNII channel, or any other band less that about 20GHz. The second frequency band could be a higher frequency range, such as the band greater than 20 GHz or one centered in the 59-62 GHz spectrum. For the purposes of this description, communication using the lower frequency band is referred as out-of band (OOB) communications while communicating using higher frequency bands may be called in-band communications. Other frequency bands can also be used in alternative embodiments as the first and/or second frequency bands. The 20 GHz mark may not be the delimiter between the lower frequency band and higher frequency band. Other alternative embodiments allow the first and second frequency bands to be centered at the exact same frequencies, but can be associated with different beamwidths using antennas with different aperture sizes.
The communication device may use the first frequency band to communicate with other devices in the wireless network. OOB control information signals, or simply?first controls signals? are examples. To facilitate data communication using this second frequency band. The first control signals could contain?signals? and/or ?control information? To facilitate the initial or coarse beamforming and CFO estimation, timing syncization, and other functions of the device or other communication devices. The second frequency band may be used by the communication device to transmit or receive data to and from other devices in the wireless network. To facilitate data communication, the second frequency band may be used. The second control signal may include signals and control information that facilitate fine beamforming and CFO estimation. It also allows for timing synchronization and other functions of the communication device. Signals for tracking the beamforming, CFO and timing can be included in the next data or data signals that are to be transmitted (i.e. received and/or transmitted) using the second frequency range. There may also be signals for data such as data related to video streaming, realtime collaboration, video content downloading, audio and/or text content download/upload, and so on.
“To appreciate the various aspects of the embodiments discussed herein, we will discuss the characteristics of frequency bands with relatively broad beamwidths and those with narrow beamwidths. The characteristics of different types of antennas, including omnidirectional and directed antennas, will be discussed. A discussion will be included about the effects of using a lower frequency band as opposed to one with higher frequencies.
“This discussion starts with a brief description about beamwidths. A beamwidth refers to a spatial characteristic that is typically associated with dishes or antennas. An antenna’s beamwidth can be calculated by dividing the antenna aperture size by the wavelength of the signals to transmit (or receive). If the wavelengths of the signals being transmitted or received are constant, then the beamwidth will be smaller the larger the aperture. Alternately, the beamwidth can be reduced by transmitting or receiving signals with shorter wavelengths (i.e. higher frequency), while keeping the aperture size constant. Different beamwidths can result when antennas with similar aperture sizes transmit signals from different frequency bands. The above discussion is about the relationship between aperture size, beamwidth and frequency bands. However, multi-element antennas can be used to control the beamwidth. In this case, aperture size may not matter as much as the signal to be transmitted. Multi-element antennas may be used to transmit or receive signals with different beamwidths.
An antenna with a narrow aperture such as an omnidirectional antenna is a good option to achieve a broad beamwidth. An antenna with a larger aperture, such a directional antenna is an alternative to or in addition to using a high frequency band to achieve a narrower beamwidth. Alternately, an antenna can provide different beamwidths by changing the frequency bands (i.e. higher or lower frequency band) of the signals that are to be transmitted and/or receive. Multi-element antennas can be used to provide different beamwidths in other frequencies, as mentioned above. One set of multi-element antennas can be adaptively controlled by special protocols or procedures to provide beam directions and beam shapes. A single set of multi-element antennas can be used to provide multiple frequency bands with varying beamwidths. The phrase “antenna” is used in the following description. The phrase “antenna” could refer to either a single or multi-element antenna.
“Referring to FIG. 2 Comparing the beamwidths for different frequency bands using antennas with approximately the same aperture size. One of the benefits of using lower frequency bands, such as the ISM band at 2.4GHz or the UNII band at 5.0GHz, to communicate in a wireless network, is the possibility that beamwidths associated with lower frequency bands (e.g. bands greater than 20GHz) may be greater. The higher beamwidth will allow signals to reach more devices within the wireless network because of its greater reach. The downside to using a lower frequency band because of its greater beamwidth is that there is more chance of interception and interference due to the wider wedge.
“Compared to lower frequency bands, higher frequency bands can be used for communication in a wireless network. This may lead to a narrower beamwidth as previously described. There may be less interference as a result. Aside from the narrower beamwidth, a higher frequency range may have another property: if an even higher frequency band (such the 24 or 60 GHz bands) is used, there could be additional attenuation due to distance, such as oxygen absorption. FIG. 2 shows that a higher frequency band, such as the 60 GHz band, may have a smaller beamwidth or a shorter range. Or?reach? You can reach more remote devices than those operating in a lower frequency band (e.g. 2.4 and 5.0GHz bands). Devices operating in the 60GHz band, instead of the 2.4 and 5.0GHz bands, may have lower interference risks from remote devices.
A higher frequency band is a better choice for wireless communication. This is because it allows more signal bandwidth (as more spectrum is available at higher frequencies), which can result in greater data throughput. The use of a larger bandwidth can decrease the power spectrum density of the transmit signal, and possibly decrease reliable communication range due the lower signal-to noise ratio at the receiver.
An omnidirectional antenna can be replaced by a directional antenna if the frequency band is higher for wireless communication. An antenna like this can have its advantages and drawbacks when communicating in a wireless network. One advantage to using a directional antenna is the ability to transmit signals at a higher frequency than an omnidirectional antenna. This allows for less power to be required to receive the same amount of power. The directional antenna may use radio frequency (RF), components that are less efficient and less expensive. This can be significant in certain situations, as the costs of RF parts for higher frequency communications may be much higher.
There may be some drawbacks to communicating with a wireless network that uses a higher frequency band and directional antennas. To register all communication devices within the network, an adaptable or multiple fixed antenna setting may be required. This can be time-consuming. It may also be difficult to synchronize the communication device in a network using protocols like carrier sense multiple acces and collision avoidance (CSMA/CA), or carrier sense multiple accessibility and collision detection (CSMA/CD).
“In accordance to various embodiments, characteristics of frequency bands associatedwith different beamwidths may be combined and used for wireless communication networks in accordance avec various embodiments.
“FIG. “FIG. The network 300 can be WWAN or WMAN, WLAN, WPAN or any other type of wireless network. Communication devices (CDs 302-308 can be set-top boxes (PDAs), desktop computers, laptops, set-top box, set-top computers, personal digital assistants or (PDAs), wireless mobile phones, smart devices, pagers and text messengers, as well as game devices, smart devices, smart appliances and other types of computing or communications devices. One or more of the CDs 302-308 could be a master, or access point. The other CDs can be clients or slave devices. In alternative embodiments, there may be more or less CDs in the network 300. Each CD 302-308 can communicate with other CDs in the network 300 through links 310, which may be bidirectional. The communication between CDs can be done in accordance to standards like 802.11a or 802.11b and any derivatives thereof.
“The present disclosure will be described in detail assuming that network 300 is a WPAN, that CD 302 acts as the access point, and that other CDs 304-308 act as clients devices. In alternative embodiments, network 300 could not contain an access point. In alternative embodiments, the network 300 could be an ad-hoc mesh networking network. In such cases, the access point may not be necessary. Referring to FIG. 3. In some embodiments, at most some client CDs 304-308 can arbitrarily or randomly join/leave the network 300. Client CD 304-308 may associate or authenticate itself each time it enters the network 300 (herein?associate?). The network 300 can be accessed by the client CDs 300 to allow them to?know? the other client CDs 300. The client CD is present in network 300. A client CD 304-308 can associate with the network 300 in certain embodiments by associating to the access point CD 302. In this illustration, client CD304 has just entered network 300 according to reference 312.
“The CD 304 may, upon entering the network 300, associate itself with it (e.g. via access point CD 302). According to various embodiments, the association with network 300 can be achieved using, for instance, a frequency band that has a broad beamwidth. The association signals can be transmitted using a frequency band with a broad beamwidth (herein “first beamwidth”). The authentication signals (e.g. beacons) may be received by CD 304 more easily than the CDs 302, 306 and 308 in network 300. In some embodiments, the first frequency range may be a ISM 2.4GHz, a UniI 5.0GHz, or any other band that is less than 20 GHz. The access point CD 302 can listen for signals in the first frequency band to verify or associate an entry CD 304. The components of CD 304 can then?sleep’ after successfully associating or registering with the network 300. This may be done via any of a variety of authentication and/or association protocols. It may then go into a state of?sleep’ until it receives data transmissions from any other CDs or is ready for data transmission to the network 300 (i.e. to one or more CDs in network 300).
“When client CD 304 is ready for transmit signals to one of the other CDs 302, 306, or 308 in network 300 (including access point CD 302) it may transmit first control signals that include control data using the second frequency band associated to the first beamwidth. The other CDs 302, 306, 308 and 308 in network 300 will be more likely to hear the signals if they use the same frequency band as the first beamwidth. The signals sent by client CD 304 can be heard or received. This could allow for interference to be reduced in the second frequency band as the devices now know the intentions of CD 304 and can delay their transmission for the required time. The signal parameters of the client CD 304’s first control signals may be determined by various CDs 302, 306 and 308 in different embodiments. The signal parameters of the client CD 304 may be determined by the other CDs 302, 306. and 308. This will allow them to determine the signal strength as well as the angle of arrival. The distance between the CDs 302, 306., and 308 and the client CD 304 may be determined by using the CDs 302, 306., and 308 as a guide.
Further, CD 304’s location relative to other CDs (302, 306, or 308) may be determined using other CDs 302, 306. and 308 that are based at most in part on the angle at which the initial signals were received in the first frequency band. These calculations may allow for further communication by using a second frequency band with a narrow beamwidth. The antenna systems used by the other CDs 302.306 and 308 could be correctly configured and/or aligned according to the determinations to facilitate further communication using a second frequency band between CDs 302,306, and 308 and client CD 304.
The first control signals sent through the first frequency band could facilitate communication between CD 304 and other CDs 302, 306. and 308 of network 300. This includes signals and/or control information to allow CD 304 to communicate with other CDs 302, 306. and 308 for coarse configuration. Devices then communicate with each other using a second frequency range that has a narrower beamwidth. In some embodiments, signals for medium access control (MAC), data as associated with CSMA/CA and CSMA/CD may be included in the first control signals. MAC data data will be received by each CD 302, 306, 308, and 308 if they are using the frequency band with the broadest beamwidth. Additional control information may be included in the first control signals, such as signals for initial beam-forming parameters like beam forming coefficients and synchronization parameters. Initial CFO estimation, detection, etc. can also be provided. Some embodiments may include the adaptation of the first control signal to aid beam forming, CFO estimation and/or syncization of other CDs 302, 306. and 308 in certain cases.
“Some embodiments of CDs 302-304 include antenna systems with multi-element antennas. In these cases, the first control signals transmitted in the first frequency band can include signals that facilitate different diversity techniques, such as antenna selection and maximum ratio combing, space-time codes (e.g. Alamouti code), or MIMO techniques.
The second frequency band could be higher than the first. The second frequency band could be an in-band (i.e. greater than 20 GHz), such as the 24-GHz band or a frequency range in the 59-62 GHz spectra. Higher frequency bands, such 20 GHz or higher, can provide more bandwidth than lower frequency bands (e.g. 2.4 GHz or 5.0 GHz). Communication using the second frequency band in various embodiments may be in accordance to a particular technique, such as OFDM and other modulation techniques. In some other embodiments, although the first and second frequency bands may be identical, they may have different beamwidths. This could be achieved by using antennas with different aperture sizes, or an antenna system using multi-element antennas. CD 304 can also be operated in a fallback mode if it is unable or unwilling to communicate with the second frequency bands. This means that communication will only take place via the first frequency band until the second frequency bands become available. For example, if both the receiving and transmitting devices are unable to see each other, then such a fallback mode might be necessary. Each other using the second frequency band.”
To further establish communication, the second control signals can be transmitted using the second frequency range after the first control signal has been transmitted using that frequency band. The second control signals can include signals and/or information to aid fine beam formation, fine CFO estimation, synchronization and so forth. After communication has been established using the second frequency range, signals to track beam forming, CFO estimation, timing, and other information may be sent using this frequency band.
“When client CD304 intends to leave the network 300, as indicated by reference 314, client CD304 may exchange exit information or parameters with network 300 (e.g. access point CD 302) before exiting the network 300. CD 304 can transmit exit information via the first frequency band after exiting the network 300. The reason code may be used to indicate that the application is closed, not authorized to enter the network or has not wanted to communicate with the network.
“FIG. FIG. 4 shows some types of CSMA/CA information that can be transmitted via a first frequency band and a second frequency bandwidth in a wireless network according to various embodiments. Particularly, FIG. FIG. 4 illustrates three nodes A and B communicating with one another in accordance to the CSMA/CA protocol. The first frequency band has a first beamwidth. The second frequency band has a second beamwidth. The first beamwidth may be wider or smaller than the second beamwidth. The embodiments allow the Distributed Coordination Function, DCF, Inter Frame Space, (DIFS), and Contention Window (CW), to be facilitated using one or both of the frequency bands. However, the MAC Protocol Data Unit, (MPDU), and Acknowledge (Ack), may be communicated using either the first or second frequency bands.
“FIG. “FIG. The 500 process may be used by different communication devices. It may start with a communication device entering a network at 504. The communication device may enter the network using a first frequency band (e.g. 2.4 GHz ISM or 5.0 GHz UNII bands) that is associated with a first beamwidth. Once the communication device is done communicating (e.g. transmitting and/or receiving), it may use a first frequency band (e.g. 2.4 GHz ISM band or 5.0 GHz UNII band) associated with a first beamwidth to register with the network at 506.
“On the contrary, if the communication gadget is still communicating with the network (i.e. one or more communication devices in the network), at 508, the device may exchange control signals at the first frequency band with other devices, and then communicate with them using a second frequency bandwidth associated with a second beamwidth of 512. The term “exchange” is not to be confused with the term “interchange”. The term “exchange” as used in this document may refer to a bidirectional or unidirectional exchange. Second frequency bands can be used to transmit second control signals that contain signals and/or control information. This will facilitate further communication with the second frequency band at 514. For example, the second control signals could include signals and/or control information to fine beam forming, fine CFO estimate, and/or syncization. These signals can be used in addition to the first control signals exchanged using first frequency band. This will allow for further communication using second frequency band. After communication is established using the second frequency range, signals carrying different data can be exchanged at 516. Once the communication device is done communicating with other devices in the network, the process 500 can be repeated by returning to 508
“FIG. “FIG. 6” shows portions of a communication device 600. It includes a protocol stack 604 with a variety of layers, including an application layer 606, network layer 608, medium access control layer 610, physical layer 612 and physical (PHY). A controller 602 may be added to the CD 600. This controller is a microcontroller or processor that coordinates the activities of components within the layers of CD 600. Two antennae 614 or 616 may be connected to the components of PHY Layer 612. One antenna 614 could be an omnidirectional antenna, while the other antenna 616 might be a directional one. These embodiments may allow the omnidirectional antenna to transmit or receive signals in a first frequency band associated to a first beamwidth, while the directional antenna can be used to transmit or receive signals in a second frequency range associated with a second beamwidth. The first beamwidth could be higher than the second. In some embodiments, the frequency band in which the antenna is attached may be lower than the frequency band in the second. Alternate embodiments allow only one antenna to be connected to the PHY 612. Other alternative embodiments allow for only one antenna to be coupled to the PHY layer 612.
“The components of the MAC- and PHY layer 610 and 612 (hereinafter referred to as MAC- and PHY layers) may practice various embodiments. PHY layer 612 can be modified to transmit and/or to receive first signals (i.e. first control signals) using one frequency band. This will facilitate the establishment of initial communication using another frequency band. To facilitate further communication using the second band, the PHY layer 612 can be adapted to transmit or receive second signals (i.e. second control signals). The MAC layer 610 may, however, be adapted to select one or both of the frequency bands that the PHY layer 612 uses to transmit and/or to receive the first, second, and/or third signals.
“The omnidirectional antenna 614 can be used to transmit or receive the first signals using the first frequency band. This will facilitate the initial communication between CD 600 and other CDs in a wireless network that uses the second frequency band. The directional antenna 616, on the other hand, may be used to transmit or receive the second and/or third signals using a second frequency band. This communication using the 616 is at least partially established by the first signal transmitted and/or obtained using the 614 omnidirectional antenna. The CD 600 may contain instructions to enable the CD 600 to perform previously mentioned functions.
“FIG. “FIG.7” illustrates a circuitry that transmits and/or receives signals using a first frequency band and a second frequency range in accordance to various embodiments. The circuitry 700 can be used in wireless networks and may include the following: frequency synthesizer 706, antennae 708-714, and transmitter circuitry 702. In alternative embodiments, circuitry 700 could employ any number or combinations of antennas. You should also note that the term “antennae” is not defined. Both?antennae? and?antenas? are synonymous. These terms are used interchangeably in this document.
“The circuitry 700 can operate in various environments, including an Orthogonal Frequency Multi Access (OFMA). Circuitry 700 can include super heterodyne, zero intermediate frequency (ZIF), or other types. The circuitry 700 could be, in some embodiments. It may also include the circuitries described in U.S. Patent Application Ser. No. No.
“The frequency synthesizer 706, according to some embodiments, is a frequency synthesizer which provides both a lower modulation frequency signal 716, and a higher modulation frequency frequency signal 718 to the transmitter circuitry 702 and 704. The first and second modulation frequency signals 716, 718 can be used to modulate or demodulate signals that are to be transmitted and/or received using the first and second frequency bands, respectively. The transmitter circuitry 702 can be coupled to an antenna 708 which may be an omnidirectional or directional antenna. A second antenna 710 may also be connected. The receiver circuitry 704 could be coupled to a third antenna 712, which may be a direction antenna, or a fourth antenna 714, which may be an Omnidirectional antenna.
“The relative CFO of circuitry 700 can be determined by stability in various embodiments. The same oscillator can be used for both the OOB (e.g. first frequency band) as well as the in-band (e.g. second frequency band). The absolute value of CFO might be higher for in-band (second frequency bands) operations.
The OOB operations solve the initial CFO estimation problem and the compensation problem for such systems. The frequency synthesizer 706 uses the same reference clock oscillator, so that the OOB frequency synthesis circuitry as well as the in-band frequency circuitry can be used. The relative CFOs of the signals at OOB frequency as well as in-band frequency could be the same (in ppm). For the OOB signal, it may be possible to make an initial estimate of the receiver’s CFO. After that, a revised estimate could be made and used to compensate for the coarse frequency offset at the in-band frequency. OOB signaling may be used throughout the system to track, for example, timing and carrier frequency offset.
“FIG. “FIG. 8” illustrates a frame format that can be used to communicate in a wireless network with a first frequency band and a second frequency bandwidth in accordance various embodiments. The frame format 800 could be used to represent the signal format to be transmitted or received by a communication device from one end of a wireless network to another. The first frequency band, also known as out-of-band, may be lower than 20 GHz. While the second frequency band, or in-band frequency, may be higher than 20 GHz. You should also note that the bandwidths of higher frequency bands may be greater than those of the lower frequencies. The bandwidth of the second frequency band, which may have a bandwidth between 1-2 GHz and several MHz, may be due to the increased spectra.
“The frame format 800 contains an OOB preamble 802 that is to be communicated via first frequency band. This may be used in signals adapted for signal detection and estimation. The term “preamble” is not to be confused with the term “frame format 800”. The term “preamble” as used in this document is to be interpreted broadly and can refer to any type of data packet, or part of a data packet. In certain embodiments, the OOB preamble could include medium access control data like data relating to CSMA/CA and CSMA/CD.
“The frame format 800 could also include an in-band prepamble 804 or in-band data 806 that can be transmitted using the second frequency band. In-band preamble 804 can be embedded in signals that are better suited for finer timing sync, finer CFO estimation and/or beam forming. Signals for the in-band prepamble 804 can be used to supplement control signals (e.g. initial CFO estimation, initial beam formation, etc.) that are exchanged using the first frequency range. In-band preamble 804 can facilitate communication using the second band to facilitate the communication of in-band data 806. To provide encoded service information, special field symbols can be added to the OOB preamble 802 in order to facilitate communication of the in-band data 806.
CFO is a detailed explanation of certain signals that make up the frame format 800. CFO refers to the difference in carrier frequencies between the receiver and transmitter. CFO estimation can be made more accurate if it is done using the preamble (i.e. preamble signals), of a higher frequency band like the in-band presemble 804, but the OOB preamble802 (i.e. OOB preamble signal) may be used to determine the CFO before finely estimating the CFO using in-band presemble 804. The task of fine CFO estimates may be made easier by including signals for the initial CFO estimation in signals encapsulating the OOB preamble 802.
The in-band prepamble 804 (i.e. in-band signal preamble signals) can be used to finely estimate CFOs. This may complement the OOB preamble 802. The frequency difference between the reference oscillator in a transmitting device and that in the receiving device is called the CFO. The?time scales are determined by the reference oscillators. The transmitting device and receiving device determine the?time scales?. Therefore, the CFO can be calculated as the sum of the frequency difference between the reference oscillators expressed in percent and their absolute values and the carrier frequency expressed in Hertz. CFO estimation schemes are more sensitive to absolute values of the difference between transmitter and receiver carrier frequencies. This is because the CFO values achievable will be higher if the carrier frequency is greater than the receiver’s. CFO estimates may therefore be more accurate if they are made using preamble signals communicating in a higher frequency band, such as an “in-band frequency band”.
“OOB preamble 802 signals may be used to adapt initial beam forming. Initial beam forming, as used herein refers to an initial step in beam forming calculations. It may include preliminary estimations of the angle of arrival for a signal front from a remote transmitter device. This may allow for preliminary adjustments to the antenna system of a receiving device so that it can receive the in-band preamble. This operation can also reduce the search time for the angle of arrival of in-band signals. Initial beam forming, for example, may indicate a sector in which the remote transmitting devices is operating. The initial beam forming might be used to reduce the number sectors that are needed to search for in-band signals.
Fine beam forming can be achieved by using signals that contain the in-band preamble 804. Fine beam forming can refer to the fine tuning of antennas to increase the reception quality of signals, such as in-band signals, which are signals transmitted through the second frequency band. This may involve choosing the best antenna or sector to receive the signal quality metrics. It all depends on the beam-forming algorithm. Fine beam shaping may include complex coefficients or only phase shift values calculations to combine signals from different antennae and different sectors of the sectored antenna.
“The signal containing the OOB preamble 802 could be modified for signal detection. The signals containing OOB preamble 802 could be modified to enable signal detection and indicate to receivers that they are valid. signal. Signals containing OOB preamble can be modified to indicate to receiving devices or devices that it is a signal containing valid? The message may be sent from a network communication device and not just noise or interference. The Federal Communications Commission (FCC), currently allows higher power spectral densities in lower bands (e.g. 2.4 GHz and 5.0 GHz band). Signal detection may be easier in these lower bands due to the higher likelihood that a signal is valid. The lower bands will allow signals to be correctly detected.
“The signals containing the in-band preamble 804 may be modified for fine timing syncization. Fine timing synchronization could refer to a process that locates boundaries of informational symbol within a received signal. The signals of the OOB Preamble 804 have a wider spectrum bandwidth than those of the OOB Preamble signals. These signals could have better correlation properties than, for instance, the OOB Preamble 802. By combining fine timing synchronization signal with the signals of the OOB preamble 802 you can achieve more accurate timing estimation and thus better synchronization.
“Once communication using second frequency band is established, in-band preamble 802 has been communicated and in-band preamble 804. in-band data 806 may be communicated via second frequency band. 8. In-band data 806 could include video streaming, real time collaboration, video content downloading, and so on.
“FIG. “FIG. 8 as shown. The frame format 800 in FIG. The frame format 900 has a time gap 902. The OOB preamble 802 is separated from the higher-frequency portion of the frame. This allows the receiver circuitry to switch between the first frequency bands. It also allows the relaxation processes in the circuitries to complete (see FIG. 7).”
“FIG. 10. depicts another frame format that can be used to communicate in wireless networks using a first frequency band and a second frequency bandwidth in accordance with various embodiments. The frame format 995 is identical to that of FIG. 9. However, the first frequency band can be used after the time gap 902 for tracking and/or sending information as indicated in reference 952. The first frequency band can be used to track beamforming, CFO and timing and/or to send service information, such as channel access signals, in other words. In alternative embodiments, however, the time gap 902 might not be present. You should also note that signals such as pilot signals or training signals may be contained in the OOB portion of the frame format 951
“The earlier embodiments refer to “hard?” Coupled systems that communicate using a first or second frequency band. Communication using the second band results from communication using the first band. Hard coupled systems use the first frequency range to transmit signals (e.g. first control signals) in order to enable subsequent communication using that second frequency band.
“In alternative embodiments, however, ?soft? “Soft” is another possible option. These systems may use two frequencies independently, so signal transmission and reception may overlap with the signal transmission and reception by the same system using the second frequency band. These embodiments may use a lower frequency band, such as 2.4 GHz and 5.0 GHz bands, while the second frequency band could be higher, such as those above 20, GHz (e.g. in-band bands).
The soft coupled system could use the first frequency band for processes that do not require high data throughput rates, such as network entry, bandwidth request, bandwidth grants, scheduling transmissions in a higher frequency band, and transferring feedback information which may include beam forming and power control information. The second higher frequency band, however, may be used to transmit data at high throughput rates.
“FIG. 11. shows frame formats for both the first and second frequency bands of a soft-coupled system. The first frame format 1102 corresponds to a first frequency band of 1100, while the second format 1104 corresponds with a second frequency range of 1101. The frequency band 1100 could be below 20 GHz, while the frequency band 1101 might be above 20 GHz. Frame formats 1102 or 1104 can include respective preambles 110 and 1116, frames PHY headers 1112, 1118 and frame payloads 114 and 1120. Each preamble 1110 and 1116 can be modified to allow frame detection, timing, frequency synchronization, etc., in a manner similar to the hard coupled system. The preambles of the frame formats 1102 or 1104 can be processed separately, but this is not the case with the hard coupled system. Both frame formats 1102 & 1104’s preambles may be embedded in signals that can be used to make coarse and fine estimates of CFO, timing sync, beam forming, etc.
“Both frame formats 1102 or 1104 may contain PHY headers 112 and 1118 to indicate the minimum amount of data in their associated frames payloads 114 and 120. PHY headers 1112 or 1118 can also indicate the modulation/or coding type that will be applied to frame payloads 1114/1120, beam control information, power control information for the payload, as well as other parameters. Frame PHY headers 112 and 1118 can be modulated or coded using, for instance, a predetermined modulation type and beam forming. A predetermined power control may also be applied to the PHY headers 112 and 11.18.
Both frame formats 1102 or 1104 may contain a frame payload 1114 or 1120 to carry payload information. Frame payloads 1114, 1120, and 1104 of both frame formats 1102, 1104 could include additional headers to control the interpretation and meaning of the information in the payload. These sub-headers may include MAC layer headers, which may indicate the source and/or destination addresses.
The frame payload 1114 in the first frame format 1102 could contain channel access control information, such as bandwidth requests or grants. These messages may include special messages for network entry and test signals to measure distance between stations within the network. However, these functions may be carried by preamble 1110 in alternate embodiments. The first frame format 1102 can also include fields to send feedback information back from the destination of a packet to its source. This information could relate to power control, rate control or beam forming control. It may also contain information about channel state information, transmitter and receiver performance indicators like bit error ratio and current transmit power level.
“The second frame format 1104 frame payload 1120 may contain information about higher network protocol layers.”
“The PHY headers 112 and 1118, as well as the frame payloads 114 and 1120, of both the first frame format 1102 and 1104, may contain pilot signals for estimation, tracking, frequency synchronization, timing, and/or frequency sync, and other service tasks.”
“Accessing a wireless channel in a wireless network using 1100 as the first frequency band may be possible due to contention between communication devices (e.g. stations) within the wireless network. To resolve collisions, different techniques can be used. These techniques could include CSMA/CA or CSMA/CD. To reduce collisions, different division techniques can be used. These include code division, frequency or time division, and so on. If contention-based access is used, access to the wireless channel via the first frequency band 1100 can include deterministic mechanisms. Frame exchange sequences in 1100 may include special beacon frames that are periodically transmitted to facilitate frame exchange in 1100. Transmission of frames in the 1100 frequency band may be performed at a substantially random time.
“In contrast with the previous approaches to accessing a wireless channels using the first frequency bands 1100 and 1100, accessing a wireless channel using second frequency band 1101 may not be deterministic. Accessing a wireless channel via the second frequency band may be based upon a schedule that may have been derived from communications using a lower frequency (e.g. first frequency band 1100). This could allow for more efficient use of the high-throughput channel at the higher frequency band 1101. It also reduces the overhead of channel access due to fewer back-offs and retransmissions that can be caused by collisions, such as when accessing random channels.
The first frequency band 1100 could be lower than the second, while the second band 1101 might be higher. The first frequency band 1100 could be associated to a first bandwidth 1106 and the second frequency bands 1101 with a second bandwidth 1108, with the second bandwidth 1108 being higher than the first bandwidth 1106. Some payloads can be transmitted via the first frequency band 1108, while others may be sent using the second frequency channel 1101. Network control messages, for example, are usually short and contain a few tens or more bytes of data. However, higher layer payload information can be several thousand bytes. Network control messages can be sent using the first frequency band 1101 to communicate network information, while higher layer payload information may be sent using the second frequency band 1101.
“FIG. 12. illustrates the transmitter/receiver circuitry for a soft-coupled system for independent dual band communication. Circuitry 1200 could include a transmitter circuitry 1202 or a receiver circuitry 1204. Circuitry 1200 can be coupled to a layer that controls various functions. It may include a transmitter circuitry 1202 and a receiver circuitry 1204. The frequency synthesizer 1206 may be a frequency synthesizer that operates at 2.4/5.0/60GHz. The transmitter and receiver circuitry 1202 (and 1204) are connected to the antennae 1210, 1212 by switches 1214 and 12.16. Alternate embodiments allow the transmitter and receiver circuitry 1202 or 1204 to be connected to any number antennas. The first antenna 1210, and the second antenna 1202, may be adapted to transmit or receive a first and a secondary frequency band. In these cases, the frequency band of the first antenna is lower (e.g. UNII/ISM frequency ranges) than that of the second frequency spectrum (e.g. in-band bands). The MAC layer may control switches 1214 or 1216 to enable selective communication using, for instance, an UNII/ISM frequency range and/or in-band bands.
“FIG. FIG. 13 shows another process 1300 that allows communication between a communication device and a wireless network according to various embodiments. The transmission procedure 1300 could be used to allow a communication device with a neighboring device to communicate with one another and/or a coordination device using a lower frequency (?lower) band. The first frequency band, and the second frequency band (?higher) The second frequency band. The process 1300 could be used for embodiments that are described in conjunction with at least FIGS. 8-10, where communication in a higher band precedes communication in a lower band. Nodes are the name for wireless communication devices. herein. The coordinating device can be found in at least FIG. 19.”
“Block 1302 is the part of the process 1300 that involves listening to the air in higher and lower frequencies to determine at block 1304 whether another communication device or a coordinating device transmits using the higher or lower frequency. For example, the communication device might listen to the air by sensing energy at the receiver antenna in the lower or higher band. The receiver antenna’s energy detection or information from headers (e.g.) may help determine whether another communication device or coordinating device transmits in a higher or lower band. “1118) and/or the contents of frames (e.g., 1122).
“If the communication devices determine that another device transmits, the device can receive signals and/or control information at block 1306, in the higher or lower bands. This will determine how busy a medium of this device will be. A preamble may be included in the received signals and/or control info. It could include data for medium access control, including data for carrier sensor multiple access and collision avoidance (CSMA/CA), or data for carrier sensor multiple access, collision detection (CSMA/CD). A preamble can be a physical layer signal. It may also include a lower band frame with information about channel reservations for higher bands as part of a dual band frame. The ability to receive lower-band communication may enable early detection of transmissions in the higher bands. The communication device might be able detect energy in the higher band if it fails to receive communication from the lower band.
“If the communication device determines, at block 1304, that other communication/coordinating devices are not transmitting in the higher or lower band then the communication device may use a transmission protocol that initiates transmission in the lower band, at block 1308, followed by subsequent transmission in the higher band, at block 1310. When transmitting in a higher band, the communication device may transmit in the lower band.
“FIG. 14. illustrates another process 1400 for communicating using a communication device within a wireless network according to various embodiments. If communication in the higher frequency band is set up in the lower bands and synchronized at physical layer with signals from the lower bands (e.g. As described in FIG. 10).”
“Because the upper and lower bands are synchronized, listening in the air may only be done using the lower band. If the communication device determines that another communication/coordinating device is transmitting in the lower band, at block 1404, then the communication device may receive signals, at block 1406, and/or control information in the lower and/or higher bands to determine how long a medium of the transmitting device will be busy.”
“In an embodiment signals and/or control information, such as headers and/or information related to a transmission schedule are received by the communication devices at block 1406, in lower band. Only in this embodiment, the communication device may use lower band to determine the time slots that are eligible to begin transmission in the lower frequency band at block 1408. If signals or control information are received by a communication device at block 1406, the device may use the higher frequency to decode them. One or more of these embodiments may be implemented by a communication device or system.
“If no other communication devices transmit in the lower frequency band, at block 1404, the communication device can start transmission in that band at block 1408. The communication device can then transmit in the higher band. It may also continue to transmit in the lower band at block 1410. According to the embodiments described with respect to actions 512, 514 and 516 in FIG. 5.”
“FIG. 15. illustrates a search process 1500 performed by a communication device within a wireless network according to various embodiments. The search procedure 1500 may depict operations performed by a communication device that is not aware of the presence of another communication/coordinating device (e.g. “Upon powering on the communication devices.
“At block 1502, the communication device may listen to the air in the lower band to determine, at block 1504, whether other communication/coordinating devices are transmitting in the lower band. The communication device might determine if a signal is being received from another device in the lower frequency band. A signal may be received from a neighboring device. The communication device can use the lower band at block 1506 to communicate with the device. This will determine the capability of the neighboring device in the higher band. If the neighboring device can communicate in the higher frequency, the communication device may initiate an antenna adjustment procedure in the higher frequency as described in connection with FIGS. 16 and 17
“But, if the signal is not received at block 1504, the communication device can continue listening to block 1504. Alternativly, the communication system may transmit a beacon signal at block 1510 in the lower frequency band to let other devices know that the device is present.
“FIG. 16. illustrates an antenna adjustment/link setup procedure 1600 by a communication devices in a wireless network according to various embodiments. The antenna adjustment/link establishment procedure 1600 may be initiated, for example, by one of the communication device or a neighboring communication/coordinating device that indicates a capability to communicate using the higher band (hereinafter ?initiatior?).”
“At block 1602, an initiator may transmit a test message in the higher frequency band to an intended receiver (hereinafter ‘target receiver?). This could include a coordinating and/or communication device. To facilitate adjustments and measurements by the target receiver, the test signal can be transmitted in order to establish a communication channel in the higher frequency band.
“If the target receiver is able to receive the test signal at block 1604, then the link in the higher band at 1606 will be established. The initiator can notify the target receiver (e.g. a peer station and/or a coordination device) that the link is in the higher frequency band.
“If the target receiver doesn’t receive the test signal at block 1604, the initiator or the target receiver can adjust or re-adjust their respective transmitters and receivers (e.g. directional antennas) at blocks 1608 to transmit another test signal in a higher band. The operations at blocks 1602, 1604, 1608 may be repeated until all positions and combinations of antennas have been tested by the target receiver and/or initiator. If the initiator or target node has not tested all positions and combinations of positions at block 1610 then operations 1602, 1604 and 1608 can be repeated until the link is established at block 1606. If both the target node and the initiator have not tested all positions or combinations of positions for their respective antennas, they may fail to establish the link in block 1612. Failure to establish a link can be reported to the coordinating device.
“FIG. 17. illustrates an additional antenna adjustment/link establishment procedure, 1700 by a communication apparatus in a wireless network according to various embodiments. Block 1702 is where the procedure 1700 begins with testing all possible antenna orientation combinations at the target node and the initiator. For example, the initiator may repeatedly transmit a test signal followed by re-positioning of directional transmitters/receivers of the initiator and the target node until all combinations of antenna orientations have been tested.”
“If one of the tested orientations results is a received test signal from the target node hosting target receiver at block 1704 then a link in the higher band at 1706 is established. The initiator can notify the target receiver (e.g. peer station and/or a coordination device) that the link is in the higher frequency band. If none of the test orientations results in a received signal from the target receiver, block 1704 is set. Otherwise, the initiator and target node fail establish a link within the higher band at block 1708. This failure to establish a connection may be reported to the coordinating device.
“FIG. “FIG. 18″ illustrates a signal receipt procedure 1800 by a communication unit in a wireless network according to various embodiments. This procedure may be used to receive signals from a communication device that has synchronized signals in the upper and lower bands (e.g. using a common reference oscillator), as described in connection to FIGS. 8-10.”
“At block 1802, a communications device detects test signal transmissions in the lower frequency band and performs at block 1804, coarse estimation or adjustment of timing/frequency offsets using test signals in the lower frequency band. The block 1806 block performs fine estimation and/or adjustment to the timing and frequency offsets using test signal transmitted in the higher band. Block 1808 is where the communication device receives data payloads using the higher frequency.
“FIG. 19. This illustrates a communication network 1900 that uses a coordinating device 1902 according to various embodiments. One or more communication devices, e.g. 1904, 1906 and 1908, 1910, may be capable of communicating in higher bands than in lower bands using, for instance, transceivers (e.g. TX/RX 0, TX/RX1, TX/RX2, TX/RX 3), according to various embodiments. Communication in higher bands (e.g. Links 1920, 1922. 1924. 1926. 1928. For example, antennas that are substantially Omni-directional can be used to communicate in the lower band (e.g. 1912, 1914 and 1916, 1918).
To manage access to channels in the upper bands, “lower band communication” (e.g. 1914, 1916 and 1918) can be used. A coordinating device 1902 might use the lower band to assign frequency resources (e.g. a time interval), to one or more communication devices (e.g. 1904, 1906. 1908, 1910). This is to determine if neighboring communication devices are capable, available, and/or have sufficient link quality in higher bands to establish communication using that higher band. The assigned time/and/or frequency resource may be used by one or more communication devices to determine the link availability in the higher band. They can then perform link establishment procedures, such as search routines, using the higher bands, and report this information to the coordinating device 1902. To create a schedule or connectivity table for communication devices capable of communicating with each other in the higher band, the coordinating device 1902 may collect link availability from one or more communication devices.
Communication device 1904 might want to communicate with communication devices 1910 in the higher frequency, but may be unable to do so due to a variety of reasons. For example, signal 1934 may block the signal, and 1932 will indicate that the direct link 1930 has been lost. In this case, the communication devices 1904 and 1902 can notify each other. To relay the information, the coordinating device 1902 may use the connectivity schedule/table to organize data transmission between the communication device 1904 and the communication device 1910. This can be done using the higher band communication links 1920-1922, 1924, 1924, 1906, and 1908.
To avoid interference, the coordinating device 1902 can arrange specific time and/or frequency resources to establish higher-band link establishment between communication devices (e.g. 1904, 1906. 1908, 1910). A pair of communication devices might change the positions and directions of their respective antenna systems in a link establishment routine. This could cause significant interference to higher-band transmissions from other communication devices. This interference can be avoided by the coordinating device 1902, which allocates time intervals for higher-band communication between pairs of communication devices.
“The coordinating device 1902 can further organize interference measurements by communication devices using higher bands. The interference measurements can be made by the communication devices within the time period to determine link availability in a higher band. A connectivity table might include information about the interference levels that higher-band links produce on higher-band links, and/or throughput degradation experienced by higher band links.
“Based on interference information, the 1902 coordinating device can calculate/determine a more efficient schedule for transmissions in higher bands by the communication devices. For example, the coordinating device 1902 might allow simultaneous transmissions of links with lower mutual interference or prevent simultaneous transmissions of links with higher mutual interference. The coordinating device 1902 may determine lower and higher mutual interference by comparing the received interference levels and/or corresponding throughput degradation to one another or to a pre-determined threshold interference/degradation level. This scheduling of transmissions may be based on interference information and could increase the aggregate throughput of information within the communication system 1900.
“Using the lower frequency, the coordinating devices 1902 may transmit a transmission plan for communication in the higher bandwidth by the communication device (e.g. 1904, 1906 or 1908, 1910 to the communication devices). For example, the coordinating device 1902 could broadcast a message to notify all the communication devices about the transmission schedule.
“The higher band may be used only by the communication devices, such as 1904, 1906 and 1908 or 1910. An initiating communication device could perform a search procedure in accordance to a transmission schedule from the coordinating device 1902. A search routine could include transmission of preamble/pilot signals in the higher band, and repositioning beams of transceivers. The test signal(s), which may be received by a receiving communication device, can be used to determine if the link quality in the higher frequency band is adequate and/or adjust beam settings to improve the link quality. The initiating communication device may transmit additional test signals using the higher frequency band in order to facilitate carrier frequency offset, timing synchronization and fine beam-forming adjustments in that band. After establishing a link in the higher band between initiating communication devices and receiving communication devices, either one of them may notify the coordinating device 1902 of the newly established link.
“Accordingly to different embodiments, the Coordinating Device 1902 is a communication system having circuitry according to embodiments described, for instance, in FIGS. 6-7. The coordinating device 1902 in an embodiment is an access point (AP), for wireless communication network according to IEEE 802.11 (e.g. Wi-Fi), but it is not limited in this regard. The coordinating device 1902 could also be used to operate according to other wireless technologies.
“The coordinating device 1902 can be connected to a computer network, such as the Internet (e.g. 1950), by a line 1940, such as a wire/optical fiber. Other embodiments allow the coordinating device 1902 to be connected to the computer network (e.g. 1950) via a wireless link (not illustrated). The coordinating device 1902 aims to establish higher band connections with communication devices in the communication network 1900, either directly (e.g. links 1926 and 1928), or through communication devices that act as relays to increase the throughput of the communication network 1900.
“The coordinating device 1902 could include a module that creates the connectivity list based upon received link availability information,/or interference information. A scheduling module can also be used to create a transmission schedule using the connectivity tables and/or associated information.
“Module” is used herein. “Module” may be used to refer to, or be part of, an Application Specific Integrated Circuit or (ASIC), an electronic device that executes one or more software programs or firmware programs.
“FIG. “FIG. 20” illustrates a 2000 process for coordinating communication using a coordinating device (e.g. 1902) in wireless network according to various embodiments. A coordinating device (e.g. 1902) may perform the actions/operations described with respect to the 2000 process. Block 2002 includes transmitting in a lower frequency band, an indication of a frequency resource for a communications device, and identifying one or more neighboring communication devices capable of communicating over the second frequency band.
“The time/frequency resource could, for example include a time period for the communication device use the second frequency bands or another frequency band to identify the one or more neighboring communication devices that can communicate over the second band. An embodiment includes a dedicated frequency channel (e.g. second frequency band, or another frequency interval). If a frequency boundary has been indicated or specified, then the time/frequency resources may include a time period. If a time boundary has been indicated or specified, then the time/frequency resources may include a frequency range such as a channel, band, or one or more subcarriers. This is when OFDM modulation is used.
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