Qualcomm Patent | Fast Beamforming In Multi-Antenna Rf Configurations

Patent: Fast Beamforming In Multi-Antenna Rf Configurations

Publication Number: 20200228176

Publication Date: 20200716

Applicants: Qualcomm

Abstract

Certain aspects of the present disclosure provide methods and apparatus for fast beamforming in multi-antenna radio frequency (RF) configurations. For example, according to certain aspects, devices may receive one or more reports of one or more beamforming transmit sectors. The devices may generate a list of beamforming transmit sectors based on the one or more reports, wherein the list includes the one or more beamforming transmit sectors that satisfy one or more conditions related to one or more parameters for a partial sector level sweep. The devices may also perform the partial sector level sweep based on the list of beamforming transmit sectors.

BACKGROUND

Field of the Disclosure

[0001] Certain aspects of the present disclosure generally relate to wireless communications and, more particularly, to fast beamforming in multi-antenna radio frequency (RF) configurations.

Description of Related Art

[0002] In order to address the issue of increasing bandwidth requirements demanded for wireless communications systems, different schemes are being developed to allow multiple user terminals to communicate with a single access point by sharing the channel resources while achieving high data throughputs.

[0003] Certain applications, such as virtual reality (VR) and augmented reality (AR) may demand data rates in the range of several Gigabits per second. Certain wireless communications standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, denote a set of Wireless Local Area Network (WLAN) air interface standards developed by the IEEE 802.11 committee for short-range communications (e.g., tens of meters to a few hundred meters).

[0004] Amendment 802.11ad to the WLAN standard defines the MAC and PHY layers for very high throughput (VHT) in the 60 GHz range. Operations in the 60 GHz band allow the use of smaller antennas as compared to lower frequencies. However, as compared to operating in lower frequencies, radio waves around the 60 GHz band have high atmospheric attenuation and are subject to higher levels of absorption by atmospheric gases, rain, objects, and the like, resulting in higher free space loss. The higher free space loss can be compensated for by using many small antennas, for example, arranged in a phased array.

[0005] Using a phased array, multiple antennas may be coordinated to form a coherent beam traveling in a desired direction (or beam), referred to as beamforming. An electrical field may be rotated to change this direction. The resulting transmission is polarized based on the electrical field. A receiver may also include antennas which can adapt to match or adapt to changing transmission polarity.

[0006] The procedure to adapt the transmit and receive antennas, referred to as beam form training, may be performed initially to establish a link between devices and may also be performed periodically to maintain a quality link using the best transmit and receive beams.

[0007] Unfortunately, beamforming training represents a significant amount of overhead, as the training time reduces data throughput. The amount of training time increases as the number of transmit and receive antennas increase, resulting in more beams to evaluate during training.

BRIEF SUMMARY

[0008] Certain aspects of the present disclosure provide an apparatus for wireless communications. The apparatus generally includes a first interface configured to receive one or more reports of one or more beamforming transmit sectors, and a processing system configured to generate a list of beamforming transmit sectors based on the one or more reports, wherein the list includes the one or more beamforming transmit sectors that satisfy one or more conditions related to one or more parameters for a partial sector level sweep, and wherein the first interface and processing system are configured to perform the partial sector level sweep based on the list of beamforming transmit sectors.

[0009] Certain aspects of the present disclosure provide a method for wireless communications by a network entity. The method generally includes receiving one or more reports of one or more beamforming transmit sectors, generating a list of beamforming transmit sectors based on the one or more reports, wherein the list includes the one or more beamforming transmit sectors that satisfy one or more conditions related to one or more parameters for a partial sector level sweep, and performing the partial sector level sweep based on the list of beamforming transmit sectors.

[0010] Certain aspects of the present disclosure provide an apparatus for wireless communications. The apparatus generally includes mean for receiving one or more reports of one or more beamforming transmit sectors, means for generating a list of beamforming transmit sectors based on the one or more reports, wherein the list includes the one or more beamforming transmit sectors that satisfy one or more conditions related to one or more parameters for a partial sector level sweep, and means for performing the partial sector level sweep based on the list of beamforming transmit sectors.

[0011] Certain aspects of the present disclosure provide a wireless station. The wireless station generally includes a transceiver configured to receive one or more reports of one or more beamforming transmit sectors, and a processing system configured to generate a list of beamforming transmit sectors based on the one or more reports, wherein the list includes the one or more beamforming transmit sectors that satisfy one or more conditions related to one or more parameters for a partial sector level sweep, and wherein the transceiver and processing system are further configured to perform the partial sector level sweep based on the list of beamforming transmit sectors.

[0012] Certain aspects of the present disclosure provide a non-transitory computer readable medium having instructions stored. The instructions include receiving one or more reports of one or more beamforming transmit sectors, generating a list of beamforming transmit sectors based on the one or more reports, wherein the list includes the one or more beamforming transmit sectors that satisfy one or more conditions related to one or more parameters for a partial sector level sweep,* and performing the partial sector level sweep based on the list of beamforming transmit sectors*

[0013] Aspects of the present disclosure also provide various methods, means, and computer program products corresponding to the apparatuses and operations described above.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] So that the manner in which the above-recited features of the present disclosure can be understood in detail, a more particular description, briefly summarized above, may be had by reference to aspects, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only certain typical aspects of this disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects.

[0015] FIG. 1 is a diagram of an example wireless communications network, in accordance with certain aspects of the present disclosure.

[0016] FIG. 2 is a block diagram of an example access point and example user terminals, in accordance with certain aspects of the present disclosure.

[0017] FIG. 3 is a diagram illustrating signal propagation in an implementation of phased-array antennas, in accordance with certain aspects of the present disclosure.

[0018] FIG. 4 illustrates an example beamforming training procedure, in accordance with certain aspects of the present disclosure.

[0019] FIG. 5 illustrates an example beamforming training procedure in which an initiator and responder are in synch, in accordance with certain aspects of the present disclosure.

[0020] FIG. 6 illustrates an example beamforming training procedure in which an initiator and responder are out of synch, in accordance with certain aspects of the present disclosure.

[0021] FIG. 7 illustrates an example partial sector sweep information element (IE), in accordance with certain aspects of the present disclosure.

[0022] FIG. 8 illustrates a table that defines the meaning of each field of a partial sector sweep information element, in accordance with certain aspects of the present disclosure.

[0023] FIG. 9 illustrates an example beamforming training procedure, in accordance with certain aspects of the present disclosure.

[0024] FIG. 10 illustrates example operations for performing wireless communication, in accordance with certain aspects of the present disclosure.

[0025] FIG. 11 illustrates example components capable of performing operations of FIG. 10, in accordance with certain aspects of the present disclosure.

[0026] FIG. 12 illustrates an example of transmitting modules and a receiver, in accordance with certain aspects of the present disclosure.

[0027] FIG. 13 illustrates a communications device that may include various components configured to perform operations for the techniques described herein in accordance with certain aspects of the present disclosure.

DETAILED DESCRIPTION

[0028] The development of the 802.11ay standard for 60 GHz communication is an enhancement of the existing 802.11ad (DMG-Directional Multi-Gigabit) standard. The development addresses a number of conditions including, for example, implementing high gain phased array antennas to help address high-frequency issues in order to achieve increased ranges in 60 GHz. To get these high gain antennas to point in the correct direction one or more beamforming training algorithms may be implemented. Currently, in the 802.11ad standard, usage of beamforming training algorithms based on TX sector sweep training may be provided for the case when the two devices do not have a working (control PHY) link. When implementing such training the TX sector sweep may be considered to be a very long operation, for example, when in the case where the arrays have 256/128 elements.

[0029] Uses such as Virtual Reality/Augmented Reality (AR/VR) require frequent beamforming training given the propensity of the device to be in motion due to the nature of the usage and implementation parameters. Accordingly, it can be appreciated that in cases where the link degrades or is lost, i.e. there is no control PHY connection, the devices may have to resort to TX sector sweep based on sector sweep packets. Such a sector sweep can be considered to be a relatively long time commitment. The time taken is a factor of having to sweep sector by sector. Further, the time taken can also depend on the number of transmitting modules and on the number of sectors. During this time taken, no data transmissions occur. Accordingly, it can be appreciated that such an arrangement may lead to interruption of service for too long to allow for an overall desired performance metrics to be reached.

[0030] In one or more cases and disclosed herein, a select set of sectors may be used as part of the sector sweep which are a subset of all available sectors. This set of sectors may be selected based on a set of TX sectors that were identified as good TX sectors that meet one or more desired conditions related to one or more parameters which were identified and obtained in a previous sector sweep. This smaller select subset set of sectors may be used in the current 802.11ad specification when both devices have a single antenna array. However, issues may arise when one of the devices has multiple Rx antennas. In a case where a device has multiple antennas, the device may have to switch RX antennas and further the device may have to switch RX antennas for every sector sweep the other device uses. To be more effective, the switching rate can be related to the number of sectors used by the other device. Accordingly, the number of sectors can be known in advance. This case arrangement works when such parameters are constant, but it may present with issues when it is dynamical.

[0031] Another consideration that may be taken into account is addressing the scenario where none of the sectors in the partial sectors sweep is received by the other side. If none of the sectors in the partial sectors sweep is received by the other side, a switch to a full sector sweep may be triggered and the devices may implement such a sweep together.

[0032] In some cases, the TX sectors for a sector level sweep (SLS) may be selected through a series of operations. For example, the operations may include generating an initial list of sectors based on sectors reported by the receiver as having sufficient signal-to-noise ratio (SNR). Further, the list of sectors may be extended by adding sectors known to have spatial coverage which is tangent to the spatial coverage of the sectors in the initial list. The extended list may be consolidated such that each sector is represented only once. Further, the sectors in the list may be graded based on the SNR reported by the receiver and/or relative TX sector gain. The list of sectors may also be ordered based on the grades of the sectors such that the sectors are ordered starting with sectors with a high grade that corresponds to higher SNR values. The resulting list may be used to select up to a pre-defined number of sectors to be used for a partial sector sweep.

[0033] In some cases, the procedure may be applied to TX sectors belonging to a single antenna or to TX sectors belonging to adjacent antennas pointed in different directions. In some cases, the procedure may filter out sectors which have low probability of providing sufficient SNR from the Sector Level Sweep (SLS). In some cases, sweeping over a larger number of sectors may be applied from time to time, in full or gradually, to ensure the best sectors are indeed within the list.

[0034] Thus, certain aspects of the present disclosure provide methods and apparatus for fast beamforming in multi-antenna RF configurations. By communicating one or more reports of one or more beamforming transmit sectors, an initiator and responder effectively communicate the information that can be used to facilitate fast beamforming in multi-antenna RF configurations. This may further be provided by also generating a list of beamforming transmit sectors based on the one or more reports. The list may include the one or more beamforming transmit sectors that satisfy one or more conditions related to one or more parameters for a partial sector level sweep.

[0035] Various aspects of the disclosure are described more fully hereinafter with reference to the accompanying drawings. This disclosure may, however, be embodied in many different forms and should not be construed as limited to any specific structure or function presented throughout this disclosure. Rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Based on the teachings herein one skilled in the art should appreciate that the scope of the disclosure is intended to cover any aspect of the disclosure disclosed herein, whether implemented independently of or combined with any other aspect of the disclosure. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such an apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to or other than the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim.

[0036] The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects.

[0037] Although particular aspects are described herein, many variations and permutations of these aspects fall within the scope of the disclosure. Although some benefits and advantages of the preferred aspects are mentioned, the scope of the disclosure is not intended to be limited to particular benefits, uses, or objectives. Rather, aspects of the disclosure are intended to be broadly applicable to different wireless technologies, system configurations, networks, and transmission protocols, some of which are illustrated by way of example in the figures and in the following description of the preferred aspects. The detailed description and drawings are merely illustrative of the disclosure rather than limiting, the scope of the disclosure being defined by the appended claims and equivalents thereof.

An Example Wireless Communication System

[0038] The techniques described herein may be used for various broadband wireless communication systems, including communication systems that are based on an orthogonal multiplexing scheme. Examples of such communication systems include Spatial Division Multiple Access (SDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single-Carrier Frequency Division Multiple Access (SC-FDMA) systems, and so forth. An SDMA system may utilize sufficiently different directions to simultaneously transmit data belonging to multiple user terminals. A TDMA system may allow multiple user terminals to share the same frequency channel by dividing the transmission signal into different time slots, each time slot being assigned to a different user terminal. An OFDMA system utilizes orthogonal frequency division multiplexing (OFDM), which is a modulation technique that partitions the overall system bandwidth into multiple orthogonal sub-carriers. These sub-carriers may also be called tones, bins, etc. With OFDM, each sub-carrier may be independently modulated with data. An SC-FDMA system may utilize interleaved FDMA (IFDMA) to transmit on sub-carriers that are distributed across the system bandwidth, localized FDMA (LFDMA) to transmit on a block of adjacent sub-carriers, or enhanced FDMA (EFDMA) to transmit on multiple blocks of adjacent sub-carriers. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDMA. The techniques described herein may be utilized in any type of applied to Single Carrier (SC) and SC-MIMO systems.

[0039] The teachings herein may be incorporated into (e.g., implemented within or performed by) a variety of wired or wireless apparatuses (e.g., nodes). In some aspects, a wireless node implemented in accordance with the teachings herein may comprise an access point or an access terminal.

[0040] An access point (“AP”) may comprise, be implemented as, or known as a Node B, a Radio Network Controller (“RNC”), an evolved Node B (eNB), a Base Station Controller (“BSC”), a Base Transceiver Station (“BTS”), a Base Station (“BS”), a Transceiver Function (“TF”), a Radio Router, a Radio Transceiver, a Basic Service Set (“BSS”), an Extended Service Set (“ESS”), a Radio Base Station (“RBS”), or some other terminology.

[0041] An access terminal (“AT”) may comprise, be implemented as, or known as a subscriber station, a subscriber unit, a mobile station, a remote station, a remote terminal, a user terminal, a user agent, a user device, user equipment, a user station, or some other terminology. In some implementations, an access terminal may comprise a cellular telephone, a cordless telephone, a Session Initiation Protocol (“SIP”) phone, a wireless local loop (“WLL”) station, a personal digital assistant (“PDA”), a handheld device having wireless connection capability, a Station (“STA”), or some other suitable processing device connected to a wireless modem. Accordingly, one or more aspects taught herein may be incorporated into a phone (e.g., a cellular phone or smartphone), a computer (e.g., a laptop), a portable communication device, a portable computing device (e.g., a personal data assistant), an entertainment device (e.g., a music or video device, or a satellite radio), a global positioning system device, or any other suitable device that is configured to communicate via a wireless or wired medium. In some aspects, the node is a wireless node. Such a wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as the Internet or a cellular network) via a wired or wireless communication link.

[0042] FIG. 1 illustrates a multiple-access multiple-input-multiple-output (MIMO) system 100 with access points and user terminals. For simplicity, only one access point 110 is shown in FIG. 1. An access point is generally a fixed station that communicates with the user terminals and may also be referred to as a base station or some other terminology. A user terminal may be fixed or mobile and may also be referred to as a mobile station, a wireless device or some other terminology. Access point 110 may communicate with one or more user terminals 120 at any given moment on the downlink and uplink. The downlink (i.e., forward link) is the communication link from the access point to the user terminals, and the uplink (i.e., reverse link) is the communication link from the user terminals to the access point. A user terminal may also communicate peer-to-peer with another user terminal. A system controller 130 couples to and provides coordination and control for the access points.

[0043] While portions of the following disclosure will describe user terminals 120 capable of communicating via Spatial Division Multiple Access (SDMA), for certain aspects, the user terminals 120 may also include some user terminals that do not support SDMA. Thus, for such aspects, an access point (AP) 110 may be configured to communicate with both SDMA and non-SDMA user terminals. This approach may conveniently allow older versions of user terminals (“legacy” stations) to remain deployed in an enterprise, extending their useful lifetime, while allowing newer SDMA user terminals to be introduced as deemed appropriate.

[0044] The system 100 employs multiple transmit and multiple receive antennas for data transmission on the downlink and uplink. The access point 110 is equipped with N.sub.ap antennas and represents the multiple-input (MI) for downlink transmissions and the multiple-output (MO) for uplink transmissions. A set of K selected user terminals 120 collectively represents the multiple-output for downlink transmissions and the multiple-input for uplink transmissions. For pure SDMA, it is desired to have N.sub.ap.ltoreq.K.ltoreq.1 if the data symbol streams for the K user terminals are not multiplexed in code, frequency or time by some means. K may be greater than N.sub.ap if the data symbol streams can be multiplexed using TDMA technique, different code channels with CDMA, disjoint sets of subbands with OFDM, and so on. Each selected user terminal transmits user-specific data to and/or receives user-specific data from the access point. In general, each selected user terminal may be equipped with one or multiple antennas (i.e., N.sub.ut.ltoreq.1). The K selected user terminals can have the same or a different number of antennas.

[0045] The system 100 may be a time division duplex (TDD) system or a frequency division duplex (FDD) system. For a TDD system, the downlink and uplink share the same frequency band. For an FDD system, the downlink and uplink use different frequency bands. MIMO system 100 may also utilize a single carrier or multiple carriers for transmission. Each user terminal may be equipped with a single antenna (e.g., in order to keep costs down) or multiple antennas (e.g., where the additional cost can be supported). The system 100 may also be a TDMA system if the user terminals 120 share the same frequency channel by dividing transmission/reception into different time slots, each time slot being assigned to different user terminal 120.

[0046] FIG. 2 illustrates a block diagram of access point 110 and two user terminals 120m and 120x in MIMO system 100. The access point 110 is equipped with N.sub.t antennas 224a through 224t. User terminal 120m is equipped with N.sub.ut,m antennas 252ma through 252mu, and user terminal 120x is equipped with N.sub.ut,x antennas 252xa through 252xu. The access point 110 is a transmitting entity for the downlink and a receiving entity for the uplink. Each user terminal 120 is a transmitting entity for the uplink and a receiving entity for the downlink. As used herein, a “transmitting entity” is an independently operated apparatus or device capable of transmitting data via a wireless channel, and a “receiving entity” is an independently operated apparatus or device capable of receiving data via a wireless channel. The term communication generally refers to transmitting, receiving, or both. In the following description, the subscript “dn” denotes the downlink, the subscript “up” denotes the uplink, Nup user terminals are selected for simultaneous transmission on the uplink, Ndn user terminals are selected for simultaneous transmission on the downlink, Nup may or may not be equal to Ndn, and Nup and Ndn may be static values or can change for each scheduling interval. The beam-steering or some other spatial processing technique may be used at the access point and user terminal.

[0047] On the uplink, at each user terminal 120 selected for uplink transmission, a TX data processor 288 receives traffic data from a data source 286 and control data from a controller 280. TX data processor 288 processes (e.g., encodes, interleaves, and modulates) the traffic data for the user terminal based on the coding and modulation schemes associated with the rate selected for the user terminal and provides a data symbol stream. A TX spatial processor 290 performs spatial processing on the data symbol stream and provides N.sub.ut,m transmit symbol streams for the N.sub.ut,m antennas. Each transmitter unit (TMTR) 254 receives and processes (e.g., converts to analog, amplifies, filters, and frequency upconverts) a respective transmit symbol stream to generate an uplink signal. N.sub.ut,m transmitter units 254 provide N.sub.ut,m uplink signals for transmission from N.sub.ut,m antennas 252 to the access point.

[0048] Nup user terminals may be scheduled for simultaneous transmission on the uplink. Each of these user terminals performs spatial processing on its data symbol stream and transmits its set of transmit symbol streams on the uplink to the access point.

[0049] At access point 110, N.sub.ap antennas 224a through 224ap receive the uplink signals from all Nup user terminals transmitting on the uplink. Each antenna 224 provides a received signal to a respective receiver unit (RCVR) 222. Each receiver unit 222 performs processing complementary to that performed by transmitter unit 254 and provides a received symbol stream. An RX spatial processor 240 performs receiver spatial processing on the N.sub.ap received symbol streams from N.sub.ap receiver units 222 and provides Nup recovered uplink data symbol streams. The receiver spatial processing is performed in accordance with the channel correlation matrix inversion (CCMI), minimum mean square error (MMSE), soft interference cancellation (SIC), or some other technique. Each recovered uplink data symbol stream is an estimate of a data symbol stream transmitted by a respective user terminal. An RX data processor 242 processes (e.g., demodulates, deinterleaves, and decodes) each recovered uplink data symbol stream in accordance with the rate used for that stream to obtain decoded data. The decoded data for each user terminal may be provided to a data sink 244 for storage and/or a controller 230 for further processing.

[0050] On the downlink, at access point 110, a TX data processor 210 receives traffic data from a data source 208 for Ndn user terminals scheduled for downlink transmission, control data from a controller 230, and possibly other data from a scheduler 234. The various types of data may be sent on different transport channels. TX data processor 210 processes (e.g., encodes, interleaves, and modulates) the traffic data for each user terminal based on the rate selected for that user terminal. TX data processor 210 provides Ndn downlink data symbol streams for the Ndn user terminals. A TX spatial processor 220 performs spatial processing (such as a precoding or beamforming, as described in the present disclosure) on the Ndn downlink data symbol streams, and provides N.sub.ap transmit symbol streams for the N.sub.ap antennas. Each transmitter unit 222 receives and processes a respective transmit symbol stream to generate a downlink signal. N.sub.ap transmitter units 222 providing N.sub.ap downlink signals for transmission from N.sub.ap antennas 224 to the user terminals.

[0051] At each user terminal 120, N.sub.ut,m antennas 252 receive the N.sub.ap downlink signals from access point 110. Each receiver unit 254 processes a received signal from an associated antenna 252 and provides a received symbol stream. An RX spatial processor 260 performs receiver spatial processing on N.sub.ut,m received symbol streams from N.sub.ut,m receiver units 254 and provides a recovered downlink data symbol stream for the user terminal. The receiver spatial processing is performed in accordance with the CCMI, MMSE or some other technique. An RX data processor 270 processes (e.g., demodulates, deinterleaves and decodes) the recovered downlink data symbol stream to obtain decoded data for the user terminal.

[0052] At each user terminal 120, a channel estimator 278 estimates the downlink channel response and provides downlink channel estimates, which may include channel gain estimates, SNR estimates, noise variance and so on. Similarly, a channel estimator 228 estimates the uplink channel response and provides uplink channel estimates. Controller 280 for each user terminal typically derives the spatial filter matrix for the user terminal based on the downlink channel response matrix H.sub.dn,m for that user terminal. Controller 230 derives the spatial filter matrix for the access point based on the effective uplink channel response matrix H.sub.up,eff. Controller 280 for each user terminal may send feedback information (e.g., the downlink and/or uplink eigenvectors, eigenvalues, SNR estimates, and so on) to the access point. Controllers 230 and 280 also control the operation of various processing units at access point 110 and user terminal 120, respectively.

[0053] As illustrated, in FIGS. 1 and 2, one or more user terminals 120 may send one or more High-Efficiency WLAN (HEW) packets 150, with a preamble format as described herein (e.g., in accordance with one of the example formats shown in FIGS. 3A-3B), to the access point 110 as part of an uplink (UL) MU-MIMO transmission, for example. Each HEW packet 150 may be transmitted on a set of one or more spatial streams (e.g., up to 4). For certain aspects, the preamble portion of the HEW packet 150 may include tone-interleaved long training fields (LTFs), subband-based LTFs, or hybrid LTFs (e.g., in accordance with one of the example implementations).

[0054] The HEW packet 150 may be generated by a packet generating unit 287 at the user terminal 120. The packet generating unit 287 may be implemented in the processing system of the user terminal 120, such as in the TX data processor 288, the controller 280, and/or the data source 286.

[0055] After UL transmission, the HEW packet 150 may be processed (e.g., decoded and interpreted) by a packet processing unit 243 at the access point 110. The packet processing unit 243 may be implemented in the process system of the access point 110, such as in the RX spatial processor 240, the RX data processor 242, or the controller 230. The packet processing unit 243 may process received packets differently, based on the packet type (e.g., with which amendment to the IEEE 802.11 standard the received packet complies). For example, the packet processing unit 243 may process a HEW packet 150 based on the IEEE 802.11 HEW standard, but may interpret a legacy packet (e.g., a packet complying with IEEE 802.11a/b/g) in a different manner, according to the standards amendment associated therewith.

[0056] Certain standards, such as the IEEE 802.11ay standard currently in the development phase, extend wireless communications according to existing standards (e.g., the 802.11ad standard) into the 60 GHz band. Example features to be included in such standards include channel aggregation and Channel-Bonding (CB). In general, channel aggregation utilizes multiple channels that are kept separate, while channel bonding treats the bandwidth of multiple channels as a single (wideband) channel.

[0057] As described above, operations in the 60 GHz band may allow the use of smaller antennas as compared to lower frequencies. While radio waves around the 60 GHz band have relatively high atmospheric attenuation, the higher free space loss can be compensated for by using many small antennas, for example, arranged in a phased array.

[0058] Using a phased array, multiple antennas may be coordinated to form a coherent beam traveling in a desired direction. An electrical field may be rotated to change this direction. The resulting transmission is polarized based on the electrical field. A receiver may also include antennas which can adapt to match or adapt to changing transmission polarity.

[0059] FIG. 3 is a diagram illustrating signal propagation 300 in an implementation of phased-array antennas. Phased array antennas use identical elements 310-1 through 310-4 (hereinafter referred to individually as an element 310 or collectively as elements 310). The direction in which the signal is propagated yields approximately identical gain for each element 310, while the phases of the elements 310 are different. Signals received by the elements are combined into a coherent beam with the correct gain in the desired direction.

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