BR112017003094B1 - METHOD AND APPARATUS FOR WIRELESS COMMUNICATIONS AND COMPUTER READABLE MEMORY - Google Patents

Abstract

SIGNALING OF DIFFERENT MCS SETS FOR DIFFERENT BANDWIDTHS. Certain aspects of the present disclosure relate generally to wireless communications and, more particularly, to the use of fields of a frame to indicate different sets of coding and modulation scheme (MCS) for communications in a first bandwidth and in a second bandwidth. bandwidth.

Description

References to related deposit requests

[0001] This application claims the priority of US Patent Application No. 14/832,994, filed on August 21, 2015, which claims the benefit of US Provisional Patent Application No. 62/042,721, filed on August 27, 2014 , which is attributed to the assignee of the patent application and expressly incorporated herein in its entirety by reference.

BACKGROUND FIELD OF DISCLOSURE

[0002] Certain aspects of the present disclosure relate generally to wireless communications and, more particularly, to the use of fields of a frame to indicate different sets of coding and modulation scheme (MCS) for communications in a first bandwidth and in a second bandwidth. DESCRIPTION OF RELATED TECHNIQUE

[0003] Wireless communication networks are widely employed to provide various communication services such as voice, video, packet data, messaging, broadcasting, etc. These wireless networks can be multiple access networks capable of supporting multiple users by sharing available network resources. Examples of such multiple access networks include Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA networks (OFDMA) and Single Carrier FDMA (SC-FDMA) networks.

[0004] In order to address the desire for greater coverage and greater communication range, several techniques are being developed. One such technique is the sub-one gigahertz (S1G) frequency range (e.g., operating in the 902 - 928 MHz range in the United States) being developed by the Institute of Electrical and Electronics Engineers (IEEE) 802.11ah task force . This development is driven by the desire to utilize a frequency range that has greater wireless range than other IEEE 802.11 groups and has lower jamming losses.

[0005] Another technique for achieving greater coverage and greater communication range involves wireless communications devices (e.g., stations and access points) capable of communicating with wide bandwidths (e.g., bandwidth of more than one MHz) using a one MHz bandwidth communication mode to achieve longer range communications (e.g., range extension). To facilitate communications, wireless communication devices can advertise their capabilities through various broadcasts. Wireless communications devices operating under earlier versions (e.g., IEEE Std 802.11ac) of wireless communications standards may advertise their ability to support a set of MCS that applies to the bandwidths by defining values in fields. advertising frames that devices transmit.

SUMMARY

[0006] Certain aspects of the present disclosure provide an apparatus for wireless communications. The apparatus generally includes a processing system configured to generate a frame having a first field that indicates a set of modulation and coding scheme (MCS) that the apparatus is capable of supporting for a first bandwidth and a second field that indicates a set of MCS that the apparatus is capable of supporting for a second bandwidth, wherein different values of the second field indicate different MCS sets that the apparatus is capable of supporting for the second bandwidth; and an interface configured to produce the frame for transmission.

[0007] Certain aspects of the present disclosure provide an apparatus for wireless communications. The apparatus generally includes an interface for receiving a frame from a wireless node having a first field and a second field; and a processing system configured to determine, from a value of the first field, a set of modulation and coding scheme (MCS) that the wireless node supports for a first bandwidth, to determine, from a value of the second field, a set of MCS that the wireless node supports for a second bandwidth and to configure the device to communicate with the wireless node using at least one of: the first bandwidth and an MCS in the first set of MCS, or the second bandwidth and an MCS in the second set of MCS.

[0008] Certain aspects of the present disclosure provide a method for wireless communications by an apparatus. The method generally includes generating a frame that has a first field that indicates a set of modulation and coding scheme (MCS) that the apparatus is capable of supporting for a first bandwidth and a second field that indicates a set of MCS that the apparatus is capable of supporting for a second bandwidth, wherein different values of the second field indicate different MCS sets that the apparatus is capable of supporting for the second bandwidth; and produce the frame for transmission.

[0009] Certain aspects of the present disclosure provide a method for wireless communications by an apparatus. The method generally includes receiving a frame from a wireless node having a first field and a second field; and determining, from a value of the first field, a set of modulation and coding scheme (MCS) that the wireless node supports for a first bandwidth, determining, from a value of the second field, a set of MCS that the wireless node supports for a second bandwidth and communicate with the wireless node using at least one of: the first bandwidth and an MCS in the first set of MCS, or the second bandwidth and an MCS in the second set of MCS.

[0010] Certain aspects of the present disclosure provide an apparatus for wireless communications. The apparatus generally includes means for generating a frame having a first field that indicates a set of modulation and coding scheme (MCS) that the apparatus is capable of supporting for a first bandwidth and a second field that indicates a set of MCS. that the apparatus is capable of supporting for a second bandwidth, wherein different values of the second field indicate different MCS sets that the apparatus is capable of supporting for the second bandwidth; and means for producing the frame for transmission.

[0011] Certain aspects of the present disclosure provide an apparatus for wireless communications. The apparatus generally includes means for receiving a frame from a wireless node having a first field and a second field; and means for determining, from a value of the first field, a set of modulation and coding scheme (MCS) that the wireless node supports for a first bandwidth, means for determining, from a value of the second field , a set of MCS that the wireless node supports for a second bandwidth, and means for communicating with the wireless node using at least one of: the first bandwidth and an MCS in the first set of MCS, or the second bandwidth and an MCS in the second set of MCS.

[0012] Certain aspects of the present disclosure provide a computer-readable medium for wireless communications having instructions stored therein. The instructions generally include instructions for generating a frame that has a first field that indicates a set of modulation and coding scheme (MCS) that the apparatus is capable of supporting for a first bandwidth and a second field that indicates a set of MCS that an apparatus is capable of supporting for a second bandwidth, wherein different values of the second field indicate different MCS sets that the apparatus is capable of supporting for the second bandwidth; and produce the frame for transmission.

[0013] Certain aspects of the present disclosure provide a computer-readable medium for wireless communications having instructions stored therein. The instructions generally include instructions for receiving a frame from a wireless node having a first field and a second field; and determining, from a value of the first field, a set of modulation and coding scheme (MCS) that the wireless node supports for a first bandwidth, determining, from a value of the second field, a set of MCS that the wireless node supports for a second bandwidth and communicate with the wireless node using at least one of: the first bandwidth and an MCS in the first set of MCS, or the second bandwidth and an MCS in the second set of MCS.

[0014] Certain aspects of the present disclosure provide a station (STA). The STA generally includes at least one antenna, a processing system configured to generate a frame having a first field indicating a set of modulation and coding scheme (MCS) that the STA is capable of supporting for a first bandwidth, and a second field indicating a set of MCS that the STA is capable of supporting for a second bandwidth, wherein different values of the second field indicate different sets of MCS that the STA is capable of supporting for the second bandwidth; and a transmitter configured to transmit the frame, through at least one antenna, to a wireless node.

[0015] Certain aspects of the present disclosure provide an access point (AP). The AP generally includes at least one antenna, a receiver configured to receive, through the at least one antenna, a frame having a first field and a second field from a wireless node, a transmitter, and a processing system configured to determine , from a value of the first field, a set of modulation and coding scheme (MCS) that the wireless node supports for a first bandwidth, and to determine, from a value of the second field, a set of MCS that the wireless node supports for a second bandwidth and to configure the transmitter and receiver to communicate with the wireless node using at least one of: the first bandwidth and an MCS in the first set of MCS, or the second bandwidth and an MCS in the second set of MCS.

[0016] Certain aspects also provide various method, apparatus and computer program products capable of performing operations corresponding to those described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order that the manner in which the above-recited features of the present invention may be understood in detail, a more particular description, briefly summarized above, may be obtained by reference to aspects, some of which are illustrated in the attached drawings. It should be noted, however, that the attached drawings illustrate only some typical aspects of this disclosure and, therefore, should not be considered limiting its scope, for the description other equally effective aspects may be admitted.

[0018] FIG. 1 illustrates a diagram of an exemplary wireless communication network in accordance with certain aspects of the present disclosure.

[0019] FIG. 2 illustrates a block diagram of an exemplary access point (AP) and user terminals (UTs) in accordance with certain aspects of the present disclosure.

[0020] FIG. 3 illustrates a block diagram of an exemplary wireless node in accordance with certain aspects of the present disclosure.

[0021] FIG. 4 presents exemplary operations for wireless communications, in accordance with certain aspects of the present disclosure.

[0022] FIG. 4A illustrates exemplary means capable of performing the operations shown in FIG. 4.

[0023] FIG. 5 presents exemplary operations for wireless communications in accordance with certain aspects of the present disclosure.

[0024] FIG. 5A illustrates exemplary means capable of carrying out the operations shown in FIG. 5.

[0025] FIG. 6 illustrates an exemplary call flow in accordance with certain aspects of the present disclosure.

[0026] FIG. 7 illustrates an exemplary information element format in accordance with certain aspects of the present disclosure.

[0027] FIG. 8 illustrates exemplary subfield definitions in accordance with certain aspects of the present disclosure.

[0028] FIG. 9 illustrates an exemplary subfield map in accordance with certain aspects of the present disclosure.

[0029] FIG. 10 illustrates an exemplary subframe frame format in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

[0030] The demand for improved data transmission speeds from wireless networks has led to the development of devices capable of communicating using wide bandwidths (e.g., more than one MHz). Wireless communications devices (e.g., stations and access points) capable of communicating at wide bandwidths typically use a one MHz bandwidth communication mode to communicate over longer ranges in a technique sometimes referred to as range extension. That is, a device can use a wide bandwidth when communicating with nearby devices to have an improved data transmission rate, while communicating with another device over a long distance using a 1 MHz bandwidth communication mode to improve the reliability of communication over long distance. When communicating with the one MHz bandwidth communication mode, devices use only low modulation and coding schemes (including, for example, MCS10), because low modulation and coding schemes (MCSs) also improve reliability of communication. If a device discovers that the channel quality of a 1 MHz bandwidth channel supports higher MCSs, the device typically also discovers that the channel quality supports the use of a wider bandwidth channel (e.g. two MHz and higher) using an MCS that provides equivalent data as a one MHz bandwidth channel using higher MCSs.

[0031] Previous versions (e.g., IEEE Std 802.11ac) of wireless communications standards allow a device to use a single set of MCSs for all bandwidths supported by the device. That is, a device uses the same set of MCSs for a one MHz bandwidth channel as the device uses for a wider bandwidth channel (for example, two MHz). Aspects of the present disclosure provide improvements that allow a device to enable one set of MCS for communications on a channel of a first bandwidth (e.g., a 1 MHz bandwidth) while enabling a different set of MCS (e.g., higher MCSs) for wider bandwidth channels. Aspects of the present disclosure also provide signaling enhancements that allow a wireless node (e.g., a station (STA) or access point (AP)) to indicate a set of transmit (TX) and receive (RX) MCSs for communications of bandwidth equal to or more than two MHz and another set of MCS (e.g., a different set of MCS) for communications of bandwidth of less than one MHz.

[0032] Various aspects of the disclosure are described more fully below with reference to the accompanying drawings. This revelation can, however, be realized in many different ways and should not be interpreted as limited to any specific structure or function presented throughout this revelation. Rather, these aspects are provided so that this disclosure is thorough and complete, and will fully convey the scope of the description to those skilled in the art. Based on the teachings herein a person 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 aspects presented here. Furthermore, the scope of the invention is intended to cover such apparatus or method that is practiced using another structure, functionality, or structure and functionality in addition to or other than the various aspects of the invention set forth herein. It is to be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim.

[0033] The word “exemplary” is used here to mean “serving as an example, case, or illustration”. Any aspect described here as “exemplary” should not necessarily be construed as preferred or advantageous over other aspects.

[0034] Although particular aspects are described here, many variations and permutations of these aspects fall within the scope of the disclosure. Although some benefits and advantages of preferred aspects are mentioned, the scope of the disclosure is not intended to be limited to certain benefits, uses or purposes. 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 the following description of 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 of a Wireless Communication System

[0035] The techniques described here can 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 Space Division Multiple Access (SDMA) systems, Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single Carrier Frequency Division Multiple Access (OFDMA) systems. (FDMA-SC), and so on. An SDMA system can use sufficiently different directions to simultaneously transmit data belonging to multiple user terminals. A TDMA system can allow multiple user terminals to share the same frequency channel by dividing the transmission signal into different time partitions, each time partition being assigned to a different user terminal. An OFDMA system uses orthogonal frequency division multiplexing (OFDM), which is a modulation technique that compartmentalizes the total system bandwidth into multiple orthogonal sub-carriers. These subcarriers can also be called tones, bins, etc. With OFDM, each subcarrier can be independently modulated with data. An SC-FDMA system can use interleaved FDMA (IFDMA) to transmit on subcarriers that are distributed across the entire system bandwidth, localized FDMA (LFDMA) to transmit on a block of adjacent subcarriers, or boosted FDMA ( EFDMA) to transmit on multiple adjacent sub-carrier blocks. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDMA.

[0036] The teachings contained herein can be incorporated into (e.g., implemented within or performed by) a variety of wired or wireless devices (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.

[0037] 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 Station Controller Base (“BSC”), a Base Transceiver Station (“BTS”), a Base Station (“BS”), a Function Transceiver (“FT”), a Radio Router, a Radio Transceiver, a Service Set Base Station (“BSS”), an Extended Service Set (“ESS”), a Radio Base Station (“RBS”) or some other terminology.

[0038] An access terminal ("AT") may comprise, be implemented as, or known as a subscriber station, a subscriber unit, a mobile station (MS), a remote station, a remote terminal, a user (UT), a user agent, a user device, user apparatus (UE), 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") telephone, a wireless local circuit station ("WLL"), a personal digital assistant (“PDA”), a portable device with wireless connection capability, a Station (“STA”) or other suitable processing device connected to a wireless modem. Accordingly, one or more aspects taught herein may be incorporated into a telephone (e.g., a cell phone or smartphone), a computer (e.g., a laptop), a tablet, a portable communications 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 (GPS) device, or any other suitable device that is configured to communicate via a wired or wireless medium. In some respects, the node is a wireless node. Such a wireless node may provide, for example, connectivity to or from a network (e.g., a wide area network such as the Internet or a cellular network) via a wired or wireless communication link.

[0039] FIG. 1 illustrates a multiple input multiple output multiple access (MIMO) system 100 with access points and user terminals on which aspects of the present disclosure can be practiced. For example, one or more user terminals 120 may signal capabilities (e.g., to access point 110) using the techniques provided herein.

[0040] For simplicity, only one access point 110 is shown in FIG. 1. An access point is generally a fixed station that communicates with 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. The access point 110 may communicate with one or more user terminals 120 at any given time in 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. access. A user terminal can also communicate peer-to-peer with another user terminal. A system controller 130 attaches to and provides coordination and control for the access points.

[0041] While portions of the following disclosure describe user terminals 120 capable of communicating via Space 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 AP 110 may be configured to communicate with SDMA and non-SDMA user terminals. This approach can conveniently allow older versions of user terminals (“legacy” stations) to remain deployed in an enterprise, extending their useful life by allowing new SDMA user terminals to be introduced as deemed appropriate.

[0042] The access point 110 and user terminals 120 employ multiple transmit antennas and multiple receive antennas for data transmission in the downlink and uplink. For downlink MIMO transmissions, N antennas of access point 110 represent the multiple input (MI) portion of MIMO, while a set of K user terminals represent the multiple output (MO) portion of MIMO. Conversely, for uplink MIMO transmissions, the set of K user terminals represents the MI portion, while the Nap antennas of the access point 110 represent the MO portion. For pure SDMA, it is desirable to have Nap > K > 1 if the data symbol streams to the K user terminals are not multiplexed in code, frequency, or time by some means. K can be greater than N if data symbol streams can be multiplexed using the TDMA technique, different code channels with CDMA, disjoint sets of subbands with OFDM, and so on. Each user terminal transmits user-specified data to and/or receives user-specified data from the access point. In general, each selected user terminal can be equipped with one or several antennas (i.e. Nut > 1). The K selected user terminals can have the same or different number of antennas.

[0043] System 100 may be a time division duplexing (TDD) system or a frequency division duplexing (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. The MIMO 100 system can also use a single carrier or multiple carriers for transmission. Each user terminal can be equipped with a single antenna (e.g., to keep costs low) or multiple antennas (e.g., where additional cost can be borne). The system 100 may also be a TDMA system if the user terminals 120 share the same frequency channel by dividing the transmit/receive signal into different time slots, each time slot being assigned to a different user terminal 120.

[0044] FIG. 2 illustrates a block diagram of the access point 110 and two user terminals 120m and 120x in the MIMO system 100 which may be examples of the access point 110 and user terminals 120 described above with reference to FIG. 1 and capable of performing the techniques described here. The various processors shown in FIG. 2 may be configured to perform (or direct a device to perform) various methods described herein, e.g., the operations 400 and 500 described in association with FIGs. 4 and 5.

[0045] Access point 110 is equipped with Nt antennas 224a to 224t. The 120m user terminal is equipped with Nut,m antennas 252ma to 252mu, and the user terminal 120x is equipped with Nut,x antennas 252xa to 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 over a wireless channel, and a “receiving entity” is an independently operated apparatus or device capable of receiving data. through a wireless channel. In the following description, the subscript “dn” denotes the downlink, the subscript “up” denotes the uplink. For SDMA transmissions, Nup user terminals transmit simultaneously on the uplink, while Ndn user terminals are simultaneously transmitted on the downlink by the access point 110. Nup may or may not be the same as Ndn, and Nup and Ndn may be static values or may change for each programming interval. Beam steering or some other spatial processing technique can be used at the access point and user terminal.

[0046] In the uplink, at each user terminal 120 selected for uplink transmission, a transmission data processor (TX) 288 receives traffic data from a data source 286 and control data from a controller 280. The controller 280 may be coupled to a memory 282. The TX data processor 288 processes (e.g., encodes, interleaves, and modulates) the traffic data for the user terminal based on the encoding and modulation schemes associated with the selected rate. to the user terminal and provides a data symbol stream. A spatial processor TX 290 performs spatial processing on the data symbol stream and provides Nut,m transmission symbol streams to the Nut,m antennas. Each transmitter unit (TMTR) 254 receives and processes (e.g., converts to analog, amplifies, filters and overconverts frequency) a respective transmission symbol stream to generate an uplink signal. Nut,m transmitter units 254 provide Nut,m uplink signals for transmission from Nut,m antennas 252 to the access point.

[0047] Nup user terminals can be programmed for simultaneous transmission on the uplink. Each of these user terminals performs spatial processing on its data symbol stream and transmits its set of symbol streams in the uplink to the access point.

[0048] At access point 110, Nap antennas 224a to 224ap receive uplink signals from all Nup user terminals that transmit on the uplink. Each antenna 224 provides a received signal to a respective receiving unit (RCVR) 222. Each receiving unit 222 performs complementary processing to that performed by the transmitting unit 254 and provides a received symbol stream. An RX spatial processor 240 performs receiver spatial processing on the Nap symbol streams received from the Nap receiving units 222 and provides Nup symbol streams of recovered uplink data. Receiver spatial processing is performed according to channel correlation matrix inversion (CCMI), minimum mean square error (MMSE), soft interference cancellation (SIC), or some other technique. Each retrieved uplink data symbol stream is an estimate of a data symbol stream transmitted by a respective user terminal. An RX data processor 242 (e.g., demodulates, deinterleaves, and decodes) each retrieved 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 depot 244 for storage and/or a controller 230 for further processing. The controller 230 may be coupled to a memory 232.

[0049] In the downlink, at access point 110, a TX data processor 210 receives traffic data from a data source 208 to Ndn user terminals programmed for downlink transmission, control data from a controller 230, and possibly other data from a programmer 234. The various types of data may be sent on different transport channels. The data processor TX 210 processes (e.g., encodes, interleaves, and modulates) the traffic data for each user terminal based on the rate selected for that user terminal. The TX 210 data processor provides Ndn downlink data symbol streams to Ndn user terminals. A spatial processor TX 220 performs spatial processing (such as precoding or beamforming, as described in the present disclosure) on the Ndn downlink data symbol streams, and provides Nap transmission symbol streams to the Nap antennas. Each transmitter unit 222 receives and processes a respective transmit symbol stream to generate a downlink signal. Nap transmitter units 222 provide Nap uplink signals for transmission from Nap antennas 224 to user terminals.

[0050] At each user terminal 120, Nut,m antennas 252 receive the Nap downlink signals from the access point 110. Each receiving unit 254 processes a signal received from an associated antenna 252 and provides a received symbol stream . An RX spatial processor 260 performs receiver spatial processing on the Nut,m symbol streams received from the Nut,m receiver units 254 and provides a recovered downlink data symbol stream to the user terminal. Receiver spatial processing is performed according to 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. The decoded data for each user terminal may be provided to a data depot 272 for storage and/or a controller 280 for further processing.

[0051] 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 variation, and so on. Similarly, at access point 110, a channel estimator 228 estimates the uplink channel response and provides uplink channel estimates. The controller 280 for each user terminal typically derives the spatial filter matrix for the user terminal based on the downlink channel response matrix Hdn,m for that user terminal. The controller 230 derives the spatial filter matrix for the access point based on the effective uplink channel response matrix Hup,eff. The 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 in access point 110 and user terminal 120, respectively.

[0052] FIG. 3 illustrates exemplary components that can be used in an AP 110 and/or UT 120 to implement aspects of the present disclosure. For example, the transmitter 310, antenna(s) 316, processor 304, and/or DSP 320 may be used to practice aspects of the present disclosure implemented by an AP or UT, such as the operation 400 described in association with FIG. 4 below. Further, the receiver 312, antenna(s) 316, processor 304, and/or the DSP 320 may be used to practice aspects of the present disclosure implemented by an AP or UT, such as the operation 500 described in association with FIG. 5. The wireless node (e.g., wireless device) 302 may be an access point 110 or a user terminal 120.

[0053] The wireless node (e.g., wireless device) 302 may include a processor 304 that controls the operation of the wireless node 302. The processor 304 may also be referred to as a central processing unit (CPU). The processor 304 may control the wireless node 302 in carrying out various methods described herein, for example, the operations 400 and 500 described in association with FIGs. 4 and 5. Memory 306, which may include both read-only memory (ROM) and random access memory (RAM), provides instructions and data to processor 304. A portion of memory 306 may also include non-random access memory (RAM). volatile (NVRAM). Processor 304 typically performs logical and arithmetic operations based on program instructions stored in memory 306. Instructions in memory 306 may be executable to implement the methods described herein, for example, the operations 400 and 500 described in association with FIGs. 4 and 5.

[0054] The wireless node 302 may also include a transmitter 310 and a receiver 312 to enable the transmission and reception of data between the wireless node 302 and a remote node. The transmitter 310 and receiver 312 may be combined into a transceiver 314. A single transmit antenna or a plurality of transmit antennas 316 may be attached to the housing 308 and electrically coupled to the transceiver 314. The wireless node 302 may also include (not shown), multiple transmitters, multiple receivers, and multiple transceivers.

[0055] The wireless node 302 may also include a signal detector 318 that may be used in an effort to detect and quantify the level of signals received by the transceiver 314. The signal detector 318 may detect these signals as total energy, energy per subcarrier per symbol, power spectral density and other signals. The wireless node 302 may also include a digital signal processor (DSP) 320 for use in signal processing.

[0056] The various components of the wireless node 302 may be coupled together by a bus system 322, which may include a power bus, a control signal bus, and a status signal bus, in addition to a of data.

[0057] In general, an AP and STA can perform similar operations (e.g., symmetric or complementary). Therefore, for many of the techniques described here, an AP or STA can perform similar operations. To this end, the following description sometimes refers to an “AP/STA” to reflect that an operation can be performed by anyone. Although, it should be understood that even if only “AP” or “STA” is used, it does not mean that a corresponding operation or mechanism is limited to that type of device. Exemplary Signaling of MCS Sets for Different Bandwidths

[0058] Wireless communications devices (e.g., stations and access points) capable of communicating at wide bandwidths (e.g., bandwidth of more than one MHz) typically utilize a high-bandwidth communication mode of one MHz to achieve longer range communications (e.g., range extension). Because these devices typically use a 1 MHz bandwidth mode for range extension, the devices use only low MCS (including, for example, MCS 10) for a 1 MHz bandwidth communication mode. finds that the channel quality of a 1 MHz bandwidth channel is good enough to support higher MCSs, then the device will typically find that the channel quality is good enough to support a wider bandwidth channel (e.g. two MHz and higher) using an MCS that provides equivalent data as a one MHz channel using higher MCSs.

[0059] Previous versions (e.g., IEEE 802.11ac) of wireless communications standards allow a device to use a single set of MCSs for all bandwidths supported by the device. According to aspects of the present disclosure, methods and apparatus that allow a device to enable a set of MCS for communications on a channel of a first bandwidth (e.g., a 1 MHz bandwidth) while still enabling a set of Different MCS (e.g., supporting higher MCSs) for wider bandwidth channels are provided.

[0060] FIG. 4 illustrates exemplary operations 400 for wireless communications in accordance with aspects of the present disclosure. Operations 400 may be performed by an apparatus, e.g., a station to advertise its capabilities.

[0061] Operations 400 may begin at 402, by generating a frame that has a first field that indicates a first set of modulation and coding scheme (MCS) that the apparatus is capable of supporting for a first bandwidth and a second field indicating a second set of modulation and coding scheme (MCS) that the apparatus is capable of supporting for a second bandwidth, wherein different values of the second field indicate different MCS sets that the apparatus is capable of supporting for the second bandwidth; wherein the support may be either as a transmitter or as a receiver or both. At 404, the apparatus produces the frame for transmission.

[0062] FIG. 4A illustrates exemplary means 400A capable of performing the operations shown in FIG. 4. Exemplary means 400A may include means 402A for generating a frame having a first field indicating a first set of modulation and coding scheme (MCS) that the apparatus is capable of supporting for a first bandwidth and a second field indicating a second set of MCS that the apparatus is capable of supporting for a second bandwidth, wherein different values of the second field indicate different MCS sets that the apparatus is capable of supporting for the second bandwidth; wherein the support may be either as a transmitter or as a receiver or both. Means 402A may include, for example, controller 230, TX data processor 210, TX spatial processor 220, and/or processor 304 shown in FIG. 2 and FIG. 3. Exemplary means 400A also includes means 404A for producing the frame for transmission. Means 404A may include, for example, controller 230, TX data processor 210, TX spatial processor 220, processor 304, and/or bus system 322 shown in FIG. 2 and FIG. 3.

[0063] FIG. 5 illustrates exemplary operations 500 for wireless communications in accordance with aspects of the present disclosure. Operations 500 may be performed by a device, for example, an access point, and may be considered as complementary operations (AP side) to operations 400.

[0064] Operations 500 may begin at 502 by receiving a frame from a wireless node having a first field and a second field. At 504, the apparatus determines, from a value of the first field, a first set of modulation and coding scheme (MCS) that the wireless node supports for a first bandwidth, and from a value of the second field , a second set of MCS that the wireless node supports for a second bandwidth. At 506, the apparatus communicates with the wireless node using at least one of: the first bandwidth and an MCS in the first MCS set, or the second bandwidth and an MCS in the second MCS set.

[0065] FIG. 5A illustrates exemplary means 500A capable of performing the operations shown in FIG. 5. Exemplary means 500A includes means 502A for receiving a frame from a wireless node having a first field and a second field. The means 502A may include, for example, antennas 224, antennas 252, receiver units 222, receiver units 254, RX spatial processor 240, RX spatial processors 260, RX data processor 242, RX data processors 270, controller 230, controllers 280 , antennas 316, receiver 312, digital signal processor 320 and/or processor 304 shown in FIG. 2 and FIG. 3. Exemplary means 500A also includes means 504A for determining, from a value of the first field, a first set of modulation and coding scheme (MCS) that the wireless node supports for a first bandwidth, and, from a value of the second field, a second set of MCS that the wireless node supports for a second bandwidth. Means 504A may include, for example, data processor RX 240, data processors RX 270, controller 230, controllers 280, and/or processor 304 shown in FIG. 2 and FIG. 3. Exemplary means 500A further includes means 506A for communicating with the wireless node using at least one of: the first bandwidth and an MCS in the first MCS set, or the second bandwidth and an MCS in the second MCS set. The means 506A may include, for example, controller 230, TX data processor 210, spatial processor 220, antennas 224, antennas 252, receiver units 222, receiver units 254, RX spatial processor 240, RX spatial processors 260, RX data processor 242, RX data processors 270, controller 230, controllers 280, antennas 316, receiver 312, digital signal processor 320 and/or processor 304 shown in FIG. 2 and FIG. 3.

[0066] The operations disclosed in association with FIGs. 4 and 5 can be performed by a sub-one gigahertz station (SIG), for example. In accordance with aspects of the present disclosure, an S1G STA may declare (e.g., to other STAs and/or APs) that it is an S1G STA by announcing its S1G capabilities element.

[0067] FIG. 6 illustrates an exemplary call flow 600 between such an STA announcing its capabilities and an AP. In the exemplary call flow, the STA declares that the STA is an S1G STA transmitting an element of S1G capabilities to the AP. An example of an S1G Capabilities element is described in detail below with reference to FIG. 7.

[0068] The AP and STA then begin to communicate using S1G capabilities, including, for example, indicating a set of MCS for communications using a channel of a first bandwidth and a different set of MCS for communications using a first bandwidth channel. a second bandwidth, as described above with respect to FIGS. 4 and 5. While the exemplary call flow illustrates an STA transmitting the S1G Capabilities element to the AP, the disclosure is not limited thereto. For example, an AP may transmit an element of S1G Capabilities to a STA or another AP, and a STA may transmit an element of S1G Capabilities to another STA, for example, in a peer-to-peer network.

[0069] FIG. 7 illustrates an exemplary S1G Capabilities element in accordance with aspects of the present disclosure. The S1G Capabilities exemplary element contains a number of fields that are used to advertise S1G capabilities of an S1G STA. Element ID field 702 and Length field 704 are defined in IEEE Std 802.11. The structure of the S1G 706 Capabilities Information field is defined in IEEE Std 802.11. The supported S1G-MCS field and NSS set is used to transmit the combinations of S1G-MCSs and spatial streams that an STA supports for reception and the combinations of S1G-MCSs and spatial streams that the STA supports for transmission. The supported S1G-MCS and NSS Set subfields are described below in relation to FIG. 8.

[0070] FIG. 8 illustrates exemplary definitions 800 for subfields of a Supported S1G-MCS field and NSS Set 708, in accordance with aspects of the present disclosure. The subfields of a supported S1G-MCS field and NSS set 708 include an Rx S1G-MCS Map subfield 710, an RX Highest Supported Long G1 Data Rate subfield 712, a Tx S1G-MCS Map subfield 714, a Highest Supported Long G1 Data Rate subfield Tx 716, a Single Spatial Stream Map Rx and S1G-MCS for the 1 MHz subfield 718, and a Single Spatial Stream Tx and S1G-MCS map for the 1 MHz subfield 720 .

[0071] As described herein, the S1G-MCS Rx/Tx Map subfields 710/714 and the Single Rx/Tx Single Spatial Flow Map and S1G-MCS for 1 MHz subfields 718/720 can be used to signal Different sets of transmit (TX) and receive (RX) MCS for bandwidths greater than or equal to two MHz and another set of MCS for bandwidths less than one MHz. Example definitions for these fields are provided in the following paragraphs .

[0072] The S1G-MCS Rx Map subfield indicates the maximum MCS value of the RXVECTOR parameter of a PPDU that can be received across all channel widths supported by the STA for each number of spatial streams. However, if the Single RX Spatial Flow and S1G-MCS Map value for the 1 MHz subfield is greater than or equal to 1, only the Max S1G-MCS value for the 1 SS subfield that is indicated by the Flow subfield Single RX Spatial and S1G-MCS Map is applicable for 1 MHz channel width. For example and with reference to FIG. 9, a STA may transmit an indication that the STA can receive over bandwidths of 1 MHz, 2 MHz, 4 MHz, and 8 MHz. In the example, the STA may also transmit an S1G-MCS Rx Map subfield on a S1G capabilities with a value of 1 in the first subfield indicating that the STA can receive S1G-MCS 7 for one spatial stream, a value of 1 in the second subfield indicating that the STA can receive S1G-MCS 7 for two spatial streams, a value of 0 in the third subfield indicating that the STA can receive S1G-MCS 2 for three spatial streams and a value of 0 in the fourth subfield indicating that the STA can receive S1G-MCS 2 for four spatial streams at all indicated bandwidths. Still in the example, the STA can transmit a value of 1 in the Single RX Spatial Stream and S1G-MCS Map for the 1 MHz subfield, indicating that for a single spatial stream and a 1 MHz bandwidth channel, the STA can receive S1G-MCS 2 and not S1G-MCS 7 as indicated by the first subfield of the S1G-MCS Rx Map. In the example, the STA can receive S1G-MCS 7 in a spatial stream on 2 MHz, 4 MHz, and 8 MHz bandwidth channels.

[0073] The S1G-MCS Tx Map subfield indicates the maximum MCS value of the TXVECTOR parameter of a PPDU that can be transmitted across all channel widths supported by this STA for each number of spatial streams. However, if the Single Tx Spatial Flow and S1G-MCS Map value for the 1 MHz subfield is greater than or equal to 1, only the Max S1G-MCS value for the 1 SS subfield that is indicated by the Flow subfield Single Spatial Tx and S1G-MCS Map is applicable for 1 MHz channel width, similar to the interaction of the values of the S1G-MCS Rx Map subfield and Single Rx Spatial Lflow and S1G-MCS Map subfield, described above.

[0074] The Single Spatial Stream RX and S1G-MCS Map for the 1 MHz subfield indicates whether only a single PPDU of the single spatial stream can be received on a 1 MHz channel width by this STA. The subfield is two bits long and therefore can transmit values of 0, 1, 2, or 3. The value of 0 indicates the same number of spatial streams and the same Max S1G-MCS as indicated by the S1G-Map field. MCS Rx. A value of 1 indicates spatial flow only and with Max S1G-MCS as indicated by a value of 0 in the S1G-MCS for subfield 1 SS. A value of 2 indicates spatial flow only and with Max S1G-MCS as indicated by a value of 1 in the S1G-MCS for subfield 1 SS. A value of 3 indicates spatial flow only and with Max S1G-MCS as indicated by a value of 2 in the S1G-MCS for subfield 1 SS.

[0075] The Single Spatial Stream Tx and S1G-MCS Map for the 1 MHz subfield indicates whether only a single PPDU of the single spatial stream can be transmitted in a 1 MHz channel width by this STA. The subfield can be coded with values of 0, 1, 2 or 3. The value of 0 indicates that the STA can transmit on a 1 MHz bandwidth channel the same number of spatial streams and the same Max S1G-MCS as indicated by the S1G-MCS Tx Map subfield. A value of 1 indicates that the STA can transmit on a 1 MHz bandwidth channel a single spatial stream only and with Max S1G-MCS as indicated by a value of 0 in the S1G-MCS for subfield 1 SS. A value of 2 indicates that the STA can transmit on a 1 MHz bandwidth channel a single spatial stream only and with Max S1G-MCS as indicated by a value of 1 in the S1G-MCS for subfield 1 SS. A value of 3 indicates that the STA can transmit on a 1 MHz bandwidth channel a single spatial stream only and with Max S1G-MCS as indicated by a value of 2 in the S1G-MCS for subfield 1 SS.

[0076] An S1G STA may indicate a set of MCSs that the STA supports when receiving a channel with a bandwidth of two MHz and greater by establishing the appropriate value of the S1G-MCS Rx Map subfield as indicated in the definition shown in FIG. 8 and according to FIG. 9. Similarly, the S1G STA can indicate a set of MCSs that the STA supports when transmitting a channel with a bandwidth of two MHz and higher by establishing the appropriate value of the S1G-MCS Tx Map subfield.

[0077] The S1G STA may indicate a different set of MCSs that the STA supports when receiving a channel with a bandwidth of one MHz and lower, establishing the appropriate value of the Single Spatial Stream Rx and S1G-MCS Map for the subfield of 1 MHz. Similarly, the S1G STA can indicate a different set of MCSs that the STA supports when transmitting a channel with a bandwidth of one MHz and below, establishing the appropriate value of the Single Spatial Stream Tx and S1G-MCS Map for the 1 MHz subfield. While FIG. 8 refers to an S1G STA that indicates the different sets of MCSs that the STA supports, the disclosure is not limited to this, as APs can also indicate different sets of MCSs that the APs support by setting appropriate values in the subfields of S1G -Supported MCS and NSS Set field.

[0078] FIG. 9 illustrates an exemplary subfield encoding map 900, in accordance with aspects of the present disclosure. The Map S1G-MCS Rx and Map S1G-MCS Tx subfields illustrated in FIG. 8 can be encoded using the encodings illustrated in FIG. 9. As illustrated in FIG. 9, the exemplary S1G-MCS RX Map and S1G-MCS Map subfields comprise four subfields 902, 904, 906, 908 called Max S1G-MCS for 1 SS, Max S1G-MCS for 2 SS, Max S1G-MCS for 3 SS and Max S1G-MCS for 4 SS. Each Max S1G-MCS for n SS subfield (where n=1,..., 4) can have values from 0 to 3. A value of 0 indicates support for S1G-MCS 2 for n spatial streams. A value of 1 indicates support for S1G-MCS 7 for n spatial streams. A value of 2 indicates support for S1G-MCS 9 for n spatial streams. A value of 3 indicates that n spatial streams are not supported.

[0079] An S1G-MCS indicated as supported in the S1G-MCS Map fields for a specific number of spatial streams shall not be valid across all bandwidths and shall be limited by declaring the Highest Tx and Greater Supported Long G1 Data Rates Long G1 Data Rates Supported Rx and should be affected by additional rate selection restrictions for S1G PPDUs. For 1 MHz, MCS10 can always be supported.

[0080] For example, an STA may indicate that it supports the reception of a spatial stream transmission using MCS9 for channel widths of two MHz and greater by transmitting a value of 2 in the Max S1G-MCS for subfield 1 SS of the S1G-MCS Rx Map subfield.

[0081] The subfield that encodes the map illustrated in FIG. 9 can also be used by the Single Spatial Stream RX and Map S1G-MCS for the 1 MHz subfield and the Single Spatial Stream Tx and Map S1G-MCS for the 1 MHz subfield shown in FIG. 8. For example, an STA may indicate that it supports the reception of transmissions of a spatial stream using MCS9 for channel bandwidths of one MHz and below, transmitting a value of 3 in the Single RX Spatial Stream and S1G-MCS Map for the 1 MHz subfield (e.g., setting the value of this subfield to 3 has the effect of specifying, for 1 MHz, the same set of MCS as setting the value of subfield 902 to 2 has for larger bandwidths). As shown in FIG. 8, a similar effect indicating MCS2 or MCS7 can be achieved by setting the value of the Single Spatial Flow Rx and S1G-MCS Map to 1 (specifying a set of MCS corresponding to a value of 0 for subfield 902) or 2 (specifying a set MCS corresponding to a value of 1 for subfield 902).

[0082] The exemplary subfield encodings illustrated in FIG. 9 define sets as including MCS 10, an MCS with the indicated index number, and all MCSs with index numbers less than the indicated index number, e.g., a set may include MCS 10, MCS2, MCS1, and MCS0. However, disclosure is not limited to this, and MCS sets can be defined using other definitions.

[0083] The exemplary subfields and subfield encodings illustrated in FIGs. 7-9 refer to a “Single RX Spatial Stream and S1G-MCS Map for the 1 MHz subfield” and a “Single Tx Spatial Stream and S1G-MCS Map for the 1 MHz subfield”, however, the present revelation is not limited to wireless nodes that support a second bandwidth using only a single spatial stream. In accordance with aspects of the present disclosure, a wireless node may advertise a first capability to support a first set of MCS for a first bandwidth and a second capability to support a second set of MCS for a second bandwidth using any number of spatial streams that the wireless node can transmit and/or receive. The number of spatial streams supported for the second set of MCS and the second bandwidth may be defined in a pattern, determined from a transmitted capabilities element (e.g., an S1G Capabilities element) or some combination of the two. In accordance with aspects of the present disclosure, subfield encodings for a subfield (e.g., the subfield encoding the map in FIG. 9) used to advertise a first capability may also be used for a subfield used to advertise a second capability. For example, subfields 718 and 720 may be defined (e.g., in an IEEE 802.11 standard) as advertising a capability to support a set of MCS to transmit and receive two spatial streams for a bandwidth of 1 MHz. In the example, subfields 718 and 720 may be encoded using the encodings illustrated in FIG. 9, which are also used to encode other subfields (e.g., subfields 710 and 714) that advertise capabilities for supporting a different set of MCS at a different bandwidth.

[0084] FIG. 10 illustrates an exemplary call flow 1000 between two STA S1Gs 120m and 120x and an S1G AP 110. The call flow begins with the AP declaring that the AP is an S1G AP transmitting an S1G capabilities element at 1002. The AP indicates that the AP can receive 1, 2, 3 or 4 spatial streams using S1G-MCS 9 by transmitting “2” in all four subfields of the S1G-MCS Rx Map subfield. Similarly, the AP indicates that the AP can transmit 1, 2, 3, or 4 spatial streams using S1G-MCS 9 by transmitting “2” in all four subfields of the S1G-MCS Tx Map subfield. The AP also indicates that it can receive a 1 MHz bandwidth channel using the same numbers of spatial streams and S1G-MCS (i.e., 1, 2, 3, or 4 spatial streams using S1G-MCS) by transmitting a “ 0” in the Single Spatial Stream Rx and S1G-MCS Map for the 1 MHz subfield, abbreviated as “Rx SSS and S1G-MCS Map for 1 MHz” in FIG. 10. Similarly, the AP indicates that it can transmit a 1 MHz bandwidth channel using the same numbers of spatial streams and 1G-MCS (i.e., 1, 2, 3, or 4 spatial streams using S1G-MCS) by transmitting a “0” in the Single Spatial Stream Tx and S1G-MCS Map for the 1 MHz subfield, abbreviated as “Tx SSS and S1G-MCS Map for 1 MHz”. While call flow 1000 shows the AP making a single transmission that both STAs receive, the disclosure is not limited to this and the AP may transmit the S1G capabilities element in separate transmissions to multiple STAs.

[0085] At 1004, STA1 declares that STA1 is an S1G STA by transmitting an S1G capabilities element. STA1 indicates that it can receive 1, 2, 3, or 4 spatial streams using S1G-MCS 9 by transmitting “2” in all four subfields of the S1G-MCS Rx Map subfield. Similarly, STA1 indicates that it can transmit 1, 2, 3, or 4 spatial streams using S1G-MCS 9 by transmitting “2” in all four subfields of the S1G-MCS Tx Map subfield. STA1 also indicates that it can receive a 1 MHz bandwidth channel using the same numbers of spatial streams and S1G-MCS (i.e., 1, 2, 3, or 4 spatial streams using S1G-MCS) by transmitting a “ 0” in the Single Spatial Stream Rx and S1G-MCS Map for the 1 MHz subfield, abbreviated as “Rx SSS and S1G-MCS Map for 1 MHz” in FIG. 10. Similarly, STA1 indicates that it can transmit a 1 MHz bandwidth channel using the same numbers of spatial streams and S1G-MCS (i.e. 1, 2, 3 or 4 spatial streams using S1G-MCS) by transmitting a “0” in the Single Spatial Stream Tx and S1G-MCS Map for the 1 MHz subfield, abbreviated as “Tx SSS and S1G-MCS Map for 1 MHz”.

[0086] At 1006, STA2 declares that it is an S1G STA by transmitting an element of S1G capabilities. STA2 indicates that it can receive 1 spatial stream using S1G-MCS 9 by transmitting “2” the first subfield of the Map subfield of S1G-MCS Rx. STA2 indicates that it can receive 2 spatial streams using S1G-MCS 7 by transmitting “1” in the second subfield of the Map subfield of S1G-MCS Rx. STA2 indicates that it cannot receive 3 or 4 spatial streams by transmitting “3” in the third and fourth subfields of the S1G-MCS Rx Map subfield. As an example, STA2 may not be able to receive 3 or 4 spatial streams because STA2 has two antennas. Similarly, STA2 indicates that it can transmit 1 spatial stream using S1G-MCS 9 by transmitting “2” in the first subfield of the S1G-MCS Tx Map subfield. STA2 indicates that it can transmit 2 spatial streams using S1G-MCS 7 by transmitting “1” in the second subfield of the Map subfield of S1G-MCS Tx. STA2 indicates that it cannot transmit 3 or 4 spatial streams by transmitting “3” in the third and fourth subfields of the S1G-MCS Tx Map subfield. STA 2 indicates that it can receive a single spatial stream on a 1 MHz bandwidth channel using S1G-MCS 7 by transmitting a “2” in the Single Spatial Stream Rx and S1G-MCS Map for the 1 MHz subfield. Similarly, STA 2 indicates that it can transmit a single spatial stream on a 1 MHz bandwidth channel using S1G-MCS 7 by transmitting a “2” in the Single Spatial Stream Tx and S1G-MCS Map to the subfield 1 MHz.

[0087] At 1008, STA1 transmits data to the AP. In the exemplary call flow, good channel conditions exist between STA1 and AP, so STA1 determines to use a high-throughput, high-bandwidth transmission mode. STA1 determines from the S1G capabilities element transmitted by the AP at 1002 that the AP can receive 4 spatial streams transmitted using SIG-MCS 9. STA1 is capable of transmitting 4 spatial streams using S1G-MCS 9, and thus STA1 transmits the data to the AP using 4 spatial streams (SS) and S1G-MCS 9.

[0088] At 1010, the AP transmits data to STA1. There are still good channel conditions between STA1 and AP, so the AP determines to use a high-throughput, high-bandwidth transmission mode. The AP determines from the S1G capabilities element transmitted by STA1 at 1004 that STA1 can receive four spatial streams transmitted using SIG-MCS 9. The AP is capable of transmitting four spatial streams using S1G-MCS 9, and thus the AP transmits data to STA1 using four spatial streams (SS) and S1G-MCS 9.

[0089] At 1012, the AP transmits data to STA2. In the example call flow, there are low channel conditions (e.g., STA2 and the AP have a long distance between them) between STA2 and the AP, so the AP determines to use a 1 MHz bandwidth transmission mode. The AP determines from the S1G capabilities element transmitted by STA2 at 1006 that STA2 can receive 1 spatial stream transmitted using SIG-MCS 7 on a 1 MHz bandwidth channel. The AP is capable of transmitting 4 spatial streams using SIG-MCS 9, but the AP determines to transmit the data to STA2 using 1 spatial stream (SS) and SIG-MCS 7 on a 1 MHz bandwidth channel, due to poor channel conditions.

[0090] At 1014, STA2 transmits data to the AP. There are still low channel conditions between STA2 and AP, so STA2 determines to use a 1 MHz bandwidth transmission mode. STA2 determines from the S1G capabilities element transmitted by the AP at 1002 that the AP can receive four spatial streams transmitted using SIG-MCS 9. STA2 is capable of transmitting one spatial stream using S1G-MCS 7, and so STA1 transmits data to the AP using one spatial stream (SS) and S1G-MCS 7.

[0091] The various operations of the methods described above can be carried out by any suitable means capable of performing the corresponding functions. The means may include various hardware and/or software component(s) and/or module(s), including, but not limited to, a circuit, an application-specific integrated circuit (ASIS), or processor. Generally, where there are operations illustrated in the Figures, these operations may have corresponding counterpart means-plus-function components with similar numbering. For example, operations 400 and 500 illustrated in FIGS. 4 and 5 correspond to means 400A and 500A illustrated in FIGS. 4A and 5A, respectively.

[0092] For example, the means for transmission may comprise a transmitter (e.g., transmitter unit 222) and/or an antenna(s) 224 of the access point 110 illustrated in FIG. 2 or the transmitter 310 and/or antenna(s) 316 illustrated in FIG. 3. Means for reception may comprise a receiver (e.g., receiving unit 222) and/or an antenna(s) 224 of the access point 110 illustrated in FIG. 2 or the receiver 312 and/or antenna(s) 316 illustrated in FIG. 3. Means for processing, means for determining, means for detecting, means for scanning, means for selecting, or means for terminating the operation may comprise a processing system, which may include one or more processors, such as the RX 242 data processor , the TX data processor 210, and/or the controller 230 of the access point 110 illustrated in FIGS. 2 or the processor 304 and/or DSP 320 illustrated in FIG. 3.

[0093] In certain aspects, these means may be implemented by processing systems configured to perform the corresponding functions by implementing various algorithms (e.g., in hardware or by executing software instructions) described above to perform rapid association . For example, means for identifying wakeup periods may be implemented by a processing system that performs an algorithm that identifies wakeup periods based on a configuration (e.g., via an IE), means for determining when to enable radio functions during wakeup periods may be implemented by a (same or different) processing system that performs an algorithm that takes, as input, the wakeup periods and whether the presence of data has been indicated, while the means for enabling radio functions may be implemented by a processing system (same or different) that carries out an algorithm, which takes, as input, the decision from the means to determine and generate signals to enable/disable radio functions accordingly.

[0094] As used herein, the term “determine” encompasses a wide variety of actions. For example, “determine” may include calculating, computing, processing, deriving, investigating, querying (e.g., querying a table, a database, or other data structure), ascertaining, and the like. Furthermore, “determine” may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), and the like. Furthermore, “determine” may include resolve, select, choose, establish, and the like.

[0095] As used herein, the term receiver may refer to an RF receiver (e.g., from an RF front end) or an interface (e.g., from a processor) for receiving structures processed by an RF front end. Similarly, the term transmitter can refer to an RF transmitter of an RF front end or an interface (e.g., of a processor) to produce structures for a RF for transmission (e.g., over a bus.

[0096] As used herein, a phrase referring to “at least one of a list of items refers to any combination of those items, including individual members. As an example, “at least one of: a, b, or c” is intended to cover: a, b, c, a-b, a-c, b-c, and a-b-c.

[0097] The various logic blocks, modules and illustrative circuits described in connection with the present disclosure can be implemented or executed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any commercially available processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other type of configuration.

[0098] The steps of a method or algorithm described in relation to the present disclosure can be incorporated directly into hardware, into a software module executed by a processor, or in a combination of the two. A software module may reside on any form of storage media that is known in the art. Some examples of storage media that can be used include random access memory (RAM), read-only memory (ROM), flash memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM and etc. A software module may comprise a single instruction, or many instructions, and may be distributed over several different code segments, among different programs, and across various storage media. A storage medium may be coupled to a processor so that the processor can read information from, and write information to, the storage medium. Alternatively, the storage media may be an integral part of the processor.

[0099] The methods disclosed herein comprise one or more steps or actions for carrying out the method described. The steps and/or actions of the method can be interchanged with each other without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and/or use of the specific steps and/or actions may be modified without departing from the scope of the claims.

[0100] The described functions can be implemented in hardware, software, firmware or any combination thereof. If implemented in hardware, an exemplary hardware configuration may comprise a processing system on a wireless node. The processing system can be implemented with a bus architecture. The bus may include any number of interconnect buses and bridges depending on the specific processing system application and general design constraints. The bus can join together several circuits, including a processor, machine-readable media, and a bus interface. The bus interface can be used to connect a network adapter, among other things, to the processing system via the bus. The network adapter can be used to implement the PHY layer signal processing functions. In the case of a user terminal 120 (see FIG. 1), a user interface (e.g., keyboard, monitor, mouse, a joystick, etc.) may also be connected to the bus. The bus can also connect various other circuits such as timing supplies, peripherals, voltage regulators, power management circuits, and the like, which are well known in the art, and therefore will not be described further.

[0101] The processor may be responsible for bus management and general processing, including executing software stored on machine-readable media. The processor may be implemented with one or more general purpose and/or special purpose processors. Examples of microprocessors include, microcontrollers, DSP processors and other circuits that can run software. Software should be interpreted broadly to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Machine-readable media may include, by way of example, RAM (Random Access Memory), flash memory, ROM (Read Only Memory), PROM (Programmable Read Only Memory), EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), records, magnetic disks, optical disks, hard disks, or any other suitable storage media, or any combination thereof. Machine-readable media may be incorporated into a computer program product. The computer program product may comprise packaging materials.

[0102] In a hardware implementation, the machine-readable media may be part of the processing system separate from the processor. However, as those skilled in the art will readily appreciate, the machine-readable media, or any portion thereof, may be external to the processing system. By way of example, machine-readable media may include a transmission line, a data-modulated carrier wave, and/or a separate computer product from the wireless node, all of which can be accessed by the processor through the interface. of bus. Alternatively, or in addition, the machine-readable media, or any part thereof, may be integrated into the processor, as the case may be with cache and/or general registry files.

[0103] The processing system may be configured as a general-purpose processing system with one or more microprocessors providing processor functionality and external memory providing at least a portion of the machine-readable media, all connected with other supporting circuitry through an external bus architecture. Alternatively, the processing system may be implemented with an ASIC (Application Specific Integrated Circuit) with the processor, the bus interface, the user interface in the case of an access terminal), a support circuit, and at least one portion of the machine-readable media integrated on a single chip, or with one or more FPGAs (Field Programmable Gate Arrays), PLD (Programmable Logic Devices), controllers, state machines, closed logic, discrete hardware components, or any another suitable circuit, or any combination of circuits that can perform the various functionalities described throughout this description. Those skilled in the art will recognize the best way to implement the functionality described herein, depending on the particular application and the general design limitations imposed on the overall system.

[0104] The machine-readable media may comprise a number of software modules. Software modules include instructions that, when executed by the processor, cause the processing system to perform various functions. The software modules may include a transmit module and a receive module. Each software module can reside on a single storage device or be distributed across multiple storage devices. By way of example, a software module may be loaded into a RAM on a hard drive when a trigger event occurs. During the execution of the software module, the processor may load some of the instructions into cache to increase the access speed. One or more cache lines can then be loaded into a general register for execution by the processor. When referring to the functionality of a software module below, it should be understood that such functionality is implemented by the processor during the execution of instructions from that software module.

[0105] If implemented in software, functions may be stored or transmitted through one or more instructions or code on a computer-readable medium. Computer-readable media include computer storage media and communication media, including any medium that facilitates the transfer of a computer program from one place to another. A storage medium can be any available media that can be accessed by a computer. By way of example, and not as a limitation, such computer-readable media may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that may be used to transport or store desired program code in the form of instructions or data structures and which can be accessed by a computer. Also, any connection is properly called a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source over a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared (IR), radio, and microwave, so coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of transmission media. Disk and floppy disk, as used herein, include compact disc (“CD”), laser disc, optical disc, digital versatile disc (“DVD”), floppy disk, and Blu-ray disc where floppy disks generally reproduce data magnetically, while Discs reproduce data optically with lasers. Thus, in some respects computer-readable media may include non-transitory computer-readable media (e.g., tangible media). Furthermore, for other aspects the computer-readable media may comprise transient computer-readable media (e.g., a signal). Combinations of the above should also be included within the scope of computer-readable media.

[0106] Thus, certain aspects may comprise a computer program product to perform the operations presented herein. For example, such a computer program product may comprise a computer-readable medium having instructions stored (and/or encoded) therein, the instructions being executable by one or more processors to perform the operations described herein. For some aspects, the computer program product may include packaging material.

[0107] Furthermore, it should be noted that modules and/or other means suitable for carrying out the methods and techniques described herein may be downloaded and/or otherwise obtained by a user terminal and/or base station, as applicable. For example, such a device may be coupled to a server to facilitate the transfer of the means to perform the methods described herein. Alternatively, various methods described herein may be provided via storage media (e.g., RAM, ROM, a physical storage medium such as a compact disk (CD) or floppy disk, etc.), such that a user terminal and/or base station can achieve the various methods by coupling or providing storage media to the device. Furthermore, any other technique suitable for providing the methods and techniques described herein to a device may be used.

[0108] It should be understood that the claims are not limited to the precise configuration and components illustrated above. Various modifications, alterations and variations may be made in the arrangement, operation, and details of the methods and apparatus described above without departing from the scope of the claims.

Claims (11)

1. Method (400) for wireless communications by an apparatus, characterized in that it comprises: generating a frame (402) that has a first field that indicates a first set of modulation and coding scheme (MCS) that the apparatus is capable of supporting for a first bandwidth of a plurality of bandwidths and a second field that indicates a second set of modulation and coding scheme (MCS) that the apparatus is capable of supporting for a second bandwidth of the plurality of bandwidths, where different values of the second field indicate different MCS sets that the device is capable of supporting for the second bandwidth; and wherein the different sets of MCS indicated by different values of the second field correspond to different sets of MCS that the apparatus can indicate by different values of the first field; and producing (404) the frame for transmission, wherein the method (400) further comprises: communicating by the apparatus, using at least one of the first bandwidth and an MCS in the first set of MCS, and the second bandwidth and one MCS in the second set of MCS. 2. Method (400), according to claim 1, characterized by the fact that the different values of the second field indicate different numbers of spatial streams that the apparatus is capable of supporting in the second bandwidth using the second set of MCS. 3. Method (400), according to claim 1, characterized by the fact that: the first field further indicates that the apparatus is capable of supporting reception with the first set of MCS for the first bandwidth and the second field further indicates that the apparatus is capable of supporting reception with the second set of MCS for the second bandwidth; and the frame further comprises a third field indicating a third set of modulation and coding scheme (MCS) that the apparatus is capable of supporting for transmission in the first bandwidth and a fourth field indicating a fourth set of modulation and coding scheme (MCS) encoding (MCS) that the device is capable of supporting for transmission in the second bandwidth. 4. Method (400) for wireless communications by an apparatus, the method characterized by the fact that it comprises: receiving (502) a frame, from a wireless node (302), which has a first field and a second field ; determining (504), from a value of the first field, that the wireless node is capable of supporting a first set of modulation and coding scheme (MCS) for a first bandwidth of a plurality of bandwidths; determining, from a value of the second field, a second set of MCS that the wireless node supports for a second bandwidth of the plurality of bandwidths; and wherein the different sets of MCS indicated by different values of the second field correspond to different sets of MCS that the apparatus can indicate by different values of the first field; and communicating (506) with the wireless node (302) using at least one of: the first bandwidth and an MCS in the first set of MCS, and the second bandwidth and an MCS in the second set of MCS. 5. Method (400), according to claim 4, characterized by the fact that it further comprises: Determining, from the value of the second field, a number of spatial flows that the wireless node is capable of supporting for the second width bandwidth using the second set of MCS; and communicating (506) with the wireless node using the second bandwidth, an MCS in the second set of MCS and the determined number of spatial streams. 6. Method according to claim 4, characterized by the fact that it comprises: determining, from the value of the first field, the first set of MCS that the wireless node supports for the first bandwidth comprising determining that the node wireless is capable of supporting reception with the first set of MCS using the first bandwidth; and determining, from the value of the second field, the second set of MCS that the wireless node supports for the second bandwidth comprises determining that the wireless node is capable of supporting reception with the second set of MCS using the second bandwidth; and the method further comprises: determining from the value of a third field that the wireless node is capable of supporting a third set of MCS for transmission using the first bandwidth; and determining from a value of a fourth field that the wireless node is capable of supporting a fourth set of MCS for transmission using the second bandwidth, wherein different values of the fourth field indicate different sets of MCS that the wireless node is capable of supporting for the second bandwidth. 7. Apparatus (400A) for wireless communications characterized by the fact that it comprises: means for generating a frame (402A) having a first field that indicates a first set of modulation and coding scheme (MCS) that the apparatus is capable of support for a first bandwidth of a plurality of bandwidths and a second field that indicates a second set of modulation and coding scheme (MCS) that the apparatus is capable of supporting for a second bandwidth of the plurality of bandwidths. width, where different values of the second field indicate different MCS sets that the device is capable of supporting for the second bandwidth; and wherein the different sets of MCS indicated by different values of the second field correspond to different sets of MCS that the apparatus can indicate by different values of the first field; and means (404A) for producing the frame for transmission; and means for communicating using at least one of the first bandwidth and an MCS in the first set of MCS, and the second bandwidth and an MCS in the second set of MCS. 8. Apparatus (400A), according to claim 7, characterized by the fact that the different values of the second field indicate different numbers of spatial streams that the apparatus is capable of supporting in the second bandwidth using the second set of MCS. 9. Apparatus (400A, 500A) for wireless communications, characterized in that it comprises: means (502A) for receiving a frame, from a wireless node, having a first field and a second field; means (504A) for determining, from a value of the first field, that the wireless node is capable of supporting a first set of modulation and coding scheme (MCS) for a first bandwidth of a plurality of bandwidths ; means (504A) for determining, from a value of the second field, a second set of MCS that the wireless node supports for a second bandwidth of the plurality of bandwidths, wherein the different sets of MCS indicated by the different values of the second field correspond to different sets of MCS that the device can indicate through different values of the first field; and means (506A) for communicating with the wireless node using at least one of: the first bandwidth and an MCS in the first set of MCS, and the second bandwidth and an MCS in the second set of MCS. 10. Apparatus (400A, 500A) according to claim 9, characterized in that it further comprises: means for determining from the value of the second field, a number of spatial streams that the wireless node is capable of supporting for the second bandwidth using the second set of MCS; and means for communicating with the wireless node using the second bandwidth, an MCS in the second set of MCS, and the determined number of spatial streams. 11. Computer-readable memory, characterized by the fact that it has instructions stored therein that, when executed, cause the computer to perform the method as defined in any of claims 1 to 3 or 4 to 6.