Multiple input multiple output (MIMO) setup in millimeter wave (MMW) WLAN systems

Abstract

To set up a MIMO frame for MIMO transmission.SOLUTION: The AP / PCP may perform user selection / pairing / grouping based on measurements of analog transmissions (e.g., SINR). The SNR may be used by the station to determine a best beam and / or pair of beams and / or a worst beam and / or pair of beams, for example. The station may feed back the best number of beams and / or beam pairs for the Tx and Rx virtual antenna pairs. The station may feed back the worst several beams for the pair of Tx and Rx virtual antennas. The AP / PCP may receive an indication to group stations and / or may use the indication.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present application relates to the field of wireless communications, and in particular to the technology of MIMO in MMW WLAN systems. [Background technology]

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 365,141, filed July 21, 2016, the contents of which are incorporated by reference.

[0003] A wireless local area network (WLAN) may have multiple operating modes, such as infrastructure basic service set (BSS) mode and independent BSS (IBSS) mode. A WLAN in infrastructure BSS mode may have an access point (AP) for the BSS. One or more wireless transmit / receive units (WTRUs), e.g., stations (STAs), may be associated with the AP. The AP may have access or interface to a distribution system (DS) or other type of wired / wireless network that carries traffic within and outside the BSS. Traffic to the STA originating from outside the BSS may arrive through the AP, and the AP may distribute the traffic to the STA. In some WLAN systems, STA-STA communication may occur. In some WLAN systems, the AP may play the role of the STA. Beamforming may be used by WLAN devices. Current beamforming techniques may be limited. Summary of the Invention [Problem to be solved by the invention]

[0004] A system, method, and apparatus for setting up a multiple-input multiple-output (MIMO) frame for MIMO transmission is disclosed. [Means for solving the problem]

[0005] The AP / PCP may perform user selection / pairing / grouping based on analog transmission measurements (e.g., signal-to-noise ratio (SNR) or signal-to-interference-and-noise ratio (SINR)). The SNR / SINR may be obtained by analog beam training. During analog beam training, the AP may transmit one or more analog transmissions from the AP's virtual antenna. The AP's virtual antenna may transmit via one or more analog beams (e.g., transmissions per beam). The station may receive one or more analog transmissions via the station's virtual antenna. The station's virtual antenna may receive one or more analog transmissions via one or more analog beams. For example, the station's virtual antenna beam may receive some or all analog transmissions from the AP. The analog transmissions of one or more analog transmissions may be communicated from the AP's virtual antenna beam to the station's virtual antenna beam. The AP's virtual antenna beam and the station's virtual antenna beam may form a TX and RX beam pair. The AP's virtual antenna beam may be the TX beam in the beam pair. The station's virtual antenna beam may be the RX beam in the beam pair. Different TX and RX beam pairs may be associated with an SNR, which may be measured, for example, by a station, based on analog transmissions communicated between the TX and RX beam pairs.

[0006] The SNR may be used, for example, by a station to determine the best beam and / or beam pair and / or the worst beam and / or beam pair. In one example, an SNR threshold may be used to characterize the beam and / or beam pair. A beam and / or beam pair associated with an SNR that is equal to or greater than the SNR threshold may be characterized as the best beam and / or beam pair. A beam and / or beam pair associated with an SNR that is less than the SNR threshold may be characterized as the worst beam and / or beam pair.

[0007] The station may feedback the best beams and / or beam pairs for a pair of Tx and Rx virtual antennas. The station may feedback the worst beams for a pair of Tx and Rx virtual antennas. For example, the station may feedback the best and / or worst beams to the AP / PCP via an indication. The indication may include a MU MIMO setup frame.

[0008] The AP / PCP may receive the indication and / or use the indication to group stations. For example, the AP / PCP may receive from a station an indication of the best beam and / or worst beam for that station. The AP / PCP may receive from another station an indication of the best beam and / or worst beam for that other station. The AP / PCP may determine that the best beam for a station may be among the worst beams for another station based on one or more of the indications for multiple stations. The AP / PCP may decide to group two stations for transmission (e.g., DL MU-MIMO transmission). The AP / PCP may indicate the grouping to both stations. In this example, the AP / PCP may indicate to both stations the respective beam / RF chain / virtual antenna assignments for each station.

[0009] A more detailed understanding of the embodiments disclosed herein can be had from the following description, given by way of example in conjunction with the accompanying drawings, in which: [Brief explanation of the drawings]

[0010] [Figure 1] 1 is an exemplary sector level sweep (SLS) training. [Figure 2] 1 is an exemplary sector sweep (SSW) frame format. [Figure 3] 1 is an exemplary SSW field in an SSW frame. [Figure 4] 1 is an exemplary SSW feedback field in an SSW frame when not transmitted as part of an ISS. [Figure 5] 1 is an exemplary SSW feedback field in an SSW frame when transmitted as part of an ISS. [Figure 6] 1 is an exemplary physical layer convergence procedure (PLCP) protocol data unit (PPDU) carrying a beam improvement protocol (BRP) frame and training (TRN) field. [Figure 7] 1 is an exemplary Digital Multimedia Broadcasting (DMB) PPDU format. [Figure 8] 1 is an exemplary Enhanced Directional Multi-Gigabit (EDMG) PPDU format. [Figure 9] 1 shows an exemplary diagram of MU-MIMO analog beam training selection. [Figure 10A] FIG. 1 illustrates an exemplary multi-user (MU)-MIMO setup implementation. [Figure 10B] FIG. 1 illustrates an exemplary implementation for partial transmission impairment scheme 1. [Figure 10C] FIG. 1 illustrates an exemplary implementation for partial transmission impairment scheme 2. [Figure 11] FIG. 1 illustrates an exemplary single-user SU-MIMO setup implementation. [Figure 12] FIG. 1 illustrates an exemplary MIMO setup implementation with baseband / digital beamforming (BF) / MIMO training. [Figure 13A] FIG. 1 illustrates a linear shift technique for avoiding unintentional beamforming. [Figure 13B]FIG. 10 illustrates a technique for avoiding unintentional beamforming block-based shifts, including some or all legacy fields. [Figure 13C] FIG. 1 illustrates a technique for avoiding unintentional beamforming block-based shifts, taking into account subfields and their purpose. [Figure 14] 1 illustrates channel estimation operation in 802.11ad using a channel estimation field (CEF), which contains Golay sequences denoted as Ga128 and Gb128. [Figure 15A] FIG. 1 illustrates a circularly shifted CEF for two streams. [Figure 15B] FIG. 10 shows circularly shifted CEF and auto / cross-correlation results for two streams. [Figure 16A] FIG. 1 illustrates an exemplary wireless local area network (WLAN) device. [Figure 16B] FIG. 1 is a diagram of an example communication system in which one or more disclosed features may be implemented. [Figure 16C] FIG. 1 illustrates an exemplary wireless transmit / receive unit (WTRU). DETAILED DESCRIPTION OF THE INVENTION

[0011] A detailed description of exemplary embodiments will now be described with reference to various figures. While this description provides detailed examples of possible implementations, it should be noted that the details are illustrative and in no way limit the scope of the examples described herein.

[0012] A wireless local area network (WLAN) may have multiple operating modes, such as infrastructure basic service set (BSS) mode and independent BSS (IBSS) mode. A WLAN in BSS mode may have an access point (AP / PCP) for the BSS. One or more stations (STAs) may be associated with the AP / PCP. The AP / PCP may have access or an interface to a distribution system (DS) or another type of wired / wireless network that carries traffic within and outside the BSS. Traffic to a STA originating from outside the BSS may arrive through the AP / PCP, which may deliver the traffic to the STA. Traffic originating from a STA to a destination outside the BSS may be sent to the AP / PCP, which may deliver the traffic to the respective destination. Traffic between STAs within a BSS may be sent through the AP / PCP, e.g., from the source STA to the AP / PCP and from the AP / PCP to the destination STA. Traffic between STAs within a BSS may be peer-to-peer traffic. Peer-to-peer traffic may be transmitted directly between the source and destination STAs, for example, in a direct link setup (DLS) using 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN in IBSS mode may not have an AP / PCP, and / or STAs may communicate directly with each other. The IBSS communication mode may also be referred to as an "ad hoc" communication mode.

[0013] An AP / PCP may transmit beacons on a fixed channel (e.g., a primary channel), e.g., in 802.11ac infrastructure mode of operation. The channel may be, e.g., 20 MHz wide. The channel may be the operating channel of a BSS. The channel may be used, e.g., by STAs to establish a connection with an AP / PCP. The channel access mechanism in 802.11 systems is carrier sense multiple access with collision avoidance (CSMA / CA). STAs, including APs / PCPs, may sense the primary channel, e.g., in CSMA / CA mode of operation. To allow only one STA to transmit at a time within a given BSS, a STA may back off, e.g., when the channel is detected to be busy.

[0014] A high-throughput (HT) STA may use, for example, a 40 MHz wide channel for communication, for example, in 802.11n. A primary 20 MHz channel may be combined with an adjacent 20 MHz channel to form a 40 MHz wide contiguous channel.

[0015] A very high throughput (VHT) STA may support, for example, 20 MHz, 40 MHz, 80 MHz, and 160 MHz wide channels, for example, in 802.11ac. The 40 MHz and 80 MHz channels may be formed, for example, by combining contiguous 20 MHz channels. A 160 MHz channel may be formed, for example, by combining eight contiguous 20 MHz channels or by combining two non-contiguous 80 MHz channels, which may be referred to as an 80+80 configuration. The 80+80 configuration may pass through a segment parser that splits the data into two streams, for example, after channel coding. IFFT and time-domain processing may be performed separately for (e.g., each) stream. The streams may be mapped onto two channels. Data may be transmitted on two channels. The receiver may reverse the transmitter mechanism. The receiver may recombine the data transmitted on the multiple channels. The recombined data may be transmitted to a media access control (MAC).

[0016] Sub-1 GHz (e.g., MHz) operating modes may be supported, for example, by 802.11af and 802.11ah. Channel operating bandwidths and carriers may be reduced compared to those used, for example, by 802.11n and 802.11ac. 802.11af can support 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV White Space (TVWS) spectrum. 802.11ah can support 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths in the non-TVWS spectrum. An example use case for 802.11ah may be support for meter-type control (MTC) devices in macro coverage areas. MTC devices may have limited functionality (e.g., limited bandwidth) and may be designed for very long battery life.

[0017] WLAN systems (e.g., 802.11n, 802.11ac, 802.11af, and 802.11ah systems) may support multiple channels and channel widths, such as a channel designated as a primary channel. The primary channel may have a bandwidth equal to, for example, the largest common operating bandwidth supported by the STAs in a BSS. The bandwidth of the primary channel may be limited by the STAs that support the smallest bandwidth operating mode. In an 802.11ah example, the primary channel may be 1 MHz wide, for example, if there are one or more STAs (e.g., MTC-type devices) that support the 1 MHz mode, and the AP / PCP and other STAs can support 2 MHz, 4 MHz, 8 MHz, 16 MHz, or other channel bandwidth operating modes. Carrier sensing and NAV setting may depend on the status of the primary channel. As an example, when the primary channel has a busy status due to a STA supporting the 1 MHz operating mode transmitting to the AP / PCP on the primary channel, some or all available frequency bands may be considered busy and remain idle despite being available.

[0018] Available frequency bands may vary between different regions. As an example, in the United States, the available frequency band used by 802.11ah may be 902 MHz to 928 MHz. As another example, in South Korea, the available frequency band may be 917.5 MHz to 923.5 MHz. As another example, in Japan, the available frequency band may be 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11ah may be 6 MHz to 26 MHz depending on the country code.

[0019] 802.11ac may support downlink multi-user MIMO (MU-MIMO) transmission to multiple STAs within the same symbol time frame, e.g., during a downlink orthogonal frequency division multiplexing (OFDM) symbol. MU-MIMO transmission may improve spectral efficiency. 802.11ah may support downlink MU-MIMO. Downlink MU-MIMO may use the same symbol timing for multiple STAs, and waveform transmissions to multiple STAs may not interfere with each other. One or more STAs in MU-MIMO transmission with an AP / PCP may use the same channel or band, which may limit the operating bandwidth to a selected channel width (e.g., the smallest channel bandwidth supported by one or more STAs in MU-MIMO transmission with the AP / PCP).

[0020] 802.11ad is an amendment to the WLAN standard that specifies the media access control (MAC) and physical (PHY) layers for very high throughput (VHT) in the 60 GHz band. 802.11ad can support data rates up to 7 Gbps. 802.11ad can support three different modulation modes. 802.11ad can support single-carrier and spread-spectrum PHY control. 802.11ad can support single-carrier PHY. 802.11ad can support OFDM PHY. 802.11ad may use the 60 GHz unlicensed band, which may be available globally. At 60 GHz, the wavelength may be 5 mm, which may enable compact and competitive antennas or antenna arrays. Compact and competitive antennas may produce narrow radio frequency (RF) beams at the transmitter and receiver, which may effectively improve coverage range and / or reduce interference.

[0021] The 802.11ad frame structure may facilitate beamforming training (e.g., discovery and tracking). The beamforming (BF) training protocol may include two or more components, such as a sector-level sweep (SLS) and / or a beam improvement protocol (BRP). The SLS may be used to transmit beamforming training. The BRP may enable receive beamforming training and / or iterative improvement of both the transmit and receive beams.

[0022] MIMO transmission, including both SU-MIMO and MU-MIMO, may not be supported by 802.11ad.

[0023] FIG. 1 illustrates an exemplary sector-level sweep (SLS) training. SLS training may be performed using a beacon frame and / or a sector sweep (SSW) frame. When a beacon frame is utilized, the AP / PCP may repeat the beacon frame with multiple beams / sectors within (e.g., each) beacon interval (BI). For example, the AP / PCP may repeat the beacon frame in SS frame 102 and SS frame 106. Multiple STAs may simultaneously perform BF training. For example, a STA may respond via frame 104, and another STA may respond via frame 108. The AP / PCP may not sweep all sectors / beams within one BI, for example, due to the size of the beacon frame. STAs may need to wait multiple BIs to complete ISS training. Latency may be an issue. SSW frames may be utilized for point-to-point BF training. The SSW frames may be transmitted using a control PHY.

[0024] 2 shows an exemplary SSW frame format. The SSW frame may include one or more of Frame Control 202 (2 octets), Duration 204 (2 octets), RA 206 (6 octets), TA 208 (6 octets), SSW 210 (3 octets), SSW Feedback 212 (3 octets), or FCS 214 (4 octets).

[0025] 3 shows an example SSW field within an SSW frame. The SSW frame may include one or more of the following fields or subfields: Direction 302 (1 bit), CDOWN 304 (9 bits), Sector ID 306 (6 bits), DMG Antenna ID 308 (2 bits), and RXSS Length 310 (6 bits).

[0026] 4 shows an example SSW feedback field in an SSW frame when transmitted as part of an ISS. The SSW feedback field in the SSW frame may include one or more total sectors in the ISS 402 (9 bits), number of RX DMG antennas 404 (2 bits), reserved 406 (5 bits), must poll 408 (1 bit), and reserved 410 (7 bits) fields and subfields.

[0027] 5 shows an example SSW feedback field in an SSW frame when not transmitted as part of an initiator sector sweep (e.g., ISS). The SSW feedback field may include one or more of sector selection 502 (6 bits), DMG antenna selection 504 (2 bits), SNR report 506 (8 bits), poll required 508 (1 bit), or reserved 510 (7 bits) fields and subfields.

[0028] Beam improvement may enable a STA to improve the STA antenna configuration (e.g., antenna weight vector) for transmission and / or reception. Beam improvement may include training the receiver and / or transmitter antennas using a BRP packet. There may be two types of Beamforming Improvement Protocol (BRP) packets: a BRP receiver (RX) packet and a BRP transmitter (TX) packet. FIG. 6 is an example Physical Layer Convergence Procedure (PLCP) Protocol Data Unit (PPDU) carrying a BRP frame and a training (TRN) field. A BRP packet 602 may be carried, for example, by a Directional Multi-Gigabit (DMG) PPDU, and may be followed by a training field 604 including an Automatic Gain Control (AGC) field 606. As shown in FIG. 6, a BRP packet 602 carried by a DMG PPDU may be followed by a transmitter or receiver training field 608.

[0029] As shown in Figure 6, the value of N may be the training length given in the header field, which may indicate that the AGC has 4N subfields and that the TRN receiver / transmitter (R / T) field has 5N subfields. The channel estimation (CE) subfield 612 may be identical to that in the preamble (e.g., as described herein). The subfields in the beam training field 604 may be transmitted using rotated π / 2 binary phase shift keying (BPSK) modulation.

[0030] A BRP MAC frame may be an Action No ACK frame that contains one or more of the following fields: Category, Unprotected DMG Action, Dialog Token, BRP Request field, DMG Beam Refinement element, or Channel Measurement Feedback element 1...Channel Measurement Feedback element k.

[0031] 802.11ad can support four PHYs, including single-carrier (SC) PHY, OFDM PHY, Control PHY, and low-power SC PHY. The PHYs may share the same packet structure, but the detailed design for each field may differ. Figure 7 shows an example Digital Multimedia Broadcasting (DMB) PPDU format. The DMB PPDU format may include a short training field 702, a CE 704, a header 706, data 708, and a TRN-R / T subfield 710.

[0032] Task Group ay (TGay) may introduce modifications to both the IEEE 802.11 physical layer (PHY) and the IEEE 802.11 medium access control layer (MAC) that support a maximum throughput of at least 20 gigabits per second (e.g., as measured at the MAC data service access point) while enabling at least one mode of operation that can maintain or improve power efficiency per station. TGay may also introduce support for operation over unlicensed bands above 45 GHz while ensuring backward compatibility and coexistence with legacy directional multi-gigabit stations (e.g., as defined by the IEEE 802.11ad-2012 amendment) operating within the same band.

[0033] 802.11ay may include mobility and / or outdoor support. 802.11ay may operate within the same band as legacy standards and may include support for backward compatibility and coexistence with legacy standards within the same band. 802.11ay may include MIMO and channel bonding. To support MIMO transmission, multiple phased antenna arrays (PAAs) or PAAs with multiple polarizations may be implemented in 802.11ay-compatible devices.

[0034] The EDMG Capability element may include the antenna polarization capabilities of the EDMG STA. An EDMG STA may transmit a MIMO setup frame (e.g., a request to send (RTS) or DMG clear to send (CTS)-to-self) before transmitting an SU or MU MIMO PPDU. The MIMO setup frame may indicate one or more destination STAs addressed by the PPDU. The MIMO setup frame (e.g., RTS) transmission may trigger a response (e.g., a DMG CTS or Acknowledgment (ACK)) from one or more destination STAs.

[0035] An exemplary EDMG PPDU format is shown in Figure 8. The EDMG PPDU format may include one or more of the following fields / subfields: L-STF 802, L-CEF 804, L-HEADER 806, EDMG-HEADER-A 808, EDMG-STF 810, EDMG-CEF 812, EDMG-HEADER-B 814, Data 816, AGC 818, or TRN 820.

[0036] A multiple-input multiple-output (MIMO) setup mechanism may be provided. MIMO setup frames may be used for multiple-user (MU)-MIMO setup frames and single-user (SU)-MIMO setup frames. The MIMO setup frames may set up SU-MIMO and / or downlink (DL) MU-MIMO transmissions (e.g., in 802.11ay). In sub-6 GHz transmissions, it may not be necessary to send frames to set up MIMO transmissions. In mmW environments, transmissions may be highly directional. In single-input single-output (SISO) cases, the transmitter and / or receiver may (e.g., may need to) prepare transmitter and / or receiver Tx / Rx beams (e.g., fixed Tx / Rx beams of the transmitter and / or receiver themselves pointing toward each other). In MIMO transmissions, beam configurations may differ for different spatial / MIMO schemes. Control frames may be used to set up one or more beams at the transmitter and / or receiver side. Frames may be designed to realize some or all MIMO transmission scenarios.

[0037] Unintentional beamforming may occur. When multiple streams containing the same legacy fields (e.g., legacy short training field (STF), channel estimation field (CEF), and header) are transmitted from multiple antennas, power fluctuations (e.g., unintentional beamforming) may occur for the received signal, for example, due to strong correlation between the transmitted signals. The fluctuations in received signal power may (e.g., cause) suboptimal AGC settings to decode the legacy header in a legacy device. This may be problematic when a STA aims for omnidirectional transmission by forming a quasi-omnidirectional antenna pattern, for example, by changing its own PAA configuration. To decorrelate the transmitted signals, different cyclic shifts may be applied to (e.g., each) transmitted signal. Applying different cyclic shifts to (e.g., each) transmitted signal may be compatible with cyclic prefix (CP)-OFDM transmission, which may be intended for a single-carrier system. Single-carrier transmission may be adopted in IEEE 802.11ad. IEEE 802.11ay may be compatible with 802.11ad receivers.

[0038] A channel estimation field for multiple-stream (MIMO) transmission may be used. Techniques for reaching high throughput (e.g., throughput greater than 20 Gbps) may include using multiple-stream transmission (e.g., SU-MIMO) via multiple transmit antennas. Mutually orthogonal channel estimation fields may be constructed, for example, one for each transmit antenna, to enable SU-MIMO. One or more channel estimation fields may be identified (e.g., may need to be identified) that are orthogonal to each other and / or have the same or similar characteristics as the channel estimation field used in 802.11ad.

[0039] MIMO transmission and setup implementation may be provided. In mmW, MIMO transmission (e.g., MIMO transmission different from SISO) may use multiple radio frequency (RF) chains on the Tx / Rx side or both. There may be one or more beam patterns to be adopted on the Tx and / or Rx side. The Rx beam pattern may match (e.g., need to match) the beam pattern used on the Tx side, e.g., to achieve good BF performance. The beam used on the transmitter side may be signaled, e.g., before MIMO transmission, so that the receiver may select a matching receive beam. One or more beam modes, e.g., Type I beam mode and / or Type II beam mode, and the usage of the beam modes may be specified herein. For example, one or more of the following beam modes (e.g., Type I beam mode) may be used:

[0040] The Type I beam mode may include a basic quasi-omni mode and / or a quasi-omni mode for single data stream transmission. One or more RF chains may be used. With multiple RF chains, each (e.g., each) RF chain may form its own quasi-omni beam. In an example with two RF chains, the quasi-omni analog weights are

[0041]

number

[0042]

number

[0043] In the basic quasi-omni mode and / or quasi-omni mode for single data stream transmission, the baseband processing may include one or more of baseband / digital domain precoding, baseband / digital domain space-time coding, baseband / digital domain cyclic shift diversity (CSD), and / or baseband / digital domain antenna / polarization selection, etc. Baseband / digital domain precoding may also be used. In one or more of the examples herein, the baseband weights are W BB In the case where a single data stream may be transmitted, W BB may be of size 2 × 1. The transmitted signal may be, for example,

[0044]

number

[0045] The Type I beam mode may include a directive mode for SU-MIMO with single data stream transmission, a directive mode for SU-MIMO with multi-data stream transmission, a directive mode for MU-MIMO with single data stream transmission for (e.g., each) user, and / or a directive mode for MU-MIMO with multi-data stream transmission for (e.g., each) user.

[0046] For example, when hybrid beamforming may be utilized in the system, the analog beam mode may be set up and / or specified. The digital precoding / beam may be changed on the fly. For example, one or more of the following beam modes, which may be referred to as Type II beam mode, may be used. The Type II beam mode may include K quasi-omnidirectional beams, where K≦Kmax is the number of RF chains and / or the number of analog beams used for transmission. Kmax may be the maximum number of available RF chains and / or the maximum number of analog beams formed by the device. The value of K may be specified and / or signaled in the system. The Type II beam mode may include K directive beams for SU-MIMO, where K≦Kmax is the number of RF chains and / or the number of analog beams used for transmission. Kmax is the maximum number of available RF chains and / or the maximum number of analog beams formed by the device. The value of K may be specified and / or signaled in the system. For example, in the case of K<Kmax, the index of the analog beam (e.g., the selected analog beam) may be signaled. The Type II beam mode may include K directive beams for DL MU-MIMO, where

[0047]

Number

[0048] Transmission of DMG and / or EDMG frames may switch between beam modes (e.g., beam modes described herein). For example, in an EDMG PPDU transmission, it may be possible to switch the beam mode from the legacy preamble portion (e.g., including the Legacy Short Training Field (L-STF), Legacy Channel Estimation (L-CE), L-Header, and EDMG-Header-A fields) to the EDMG portion (e.g., including the EDMG-STF, EDMG-CE, EDMG-Header-B, and data fields). For example, in cases where a BRPTRN field may be added to the end of the PPDU, the beam mode for the training (TRN) field may be signaled in the PHY header.

[0049] Some beam modes may be designated as default beam modes. The default beam modes may be used for some transmissions that may not require (e.g., any) explicit beam setup. For example, if there is little or no signaling to explicitly signal the beam mode usage, the receiver may expect transmission in the default mode. The usage of transmitting some frames in some beam modes may be specified. For example, the default beam mode selection may follow one or more of the following rules:

[0050] The default beam mode selection may follow the rule that when a Type I beam mode is employed, for example, for broadcast or multicast management and / or control frames (e.g., beacon frames, announcement frames, etc.), the beam mode may be a basic quasi-omni mode or a quasi-omni mode for single data stream transmission using a fixed baseband scheme. For example, a basic quasi-omni mode or a quasi-omni mode for single data stream transmission with baseband precoding (e.g., a quasi-omni analog beam with baseband precoding) may be specified as the default beam mode for broadcast and / or multicast management and / or control frames. A basic quasi-omni mode or a quasi-omni mode for single data stream transmission with baseband / digital domain space-time coding (e.g., a quasi-omni analog beam with a beam mode such as baseband space-time block code (STBC)) may be specified. Any basic quasi-omni mode or a quasi-omni mode for single data stream transmission may be used. When a Type II beam mode is employed, K quasi-omnidirectional beams may be used to broadcast and / or multicast management / control frames, where K<=Kmax is the number of RF chains or analog beams used for transmission (e.g., K=Kmax or K=1). The beam mode may be specified in a standard and / or may be set up in a beacon frame. For example, when a beam mode may be set up in a beacon frame, a default beam mode may be fixed and / or used within a beacon interval. At a beacon interval (e.g., a beacon interval different from the beacon interval where the default beam mode may be fixed and used), the default beam mode may be announced by the AP / PCP (e.g., also in a beacon frame). For example, if a different (e.g., new) default beam mode is not announced, the default beam mode used within the previous beacon interval may be utilized.

[0051] The default beam mode selection may follow the rule that for unicast management / control frames, the default beam mode may be the same as for broadcast / multicast management / control frames (e.g., quasi-omnidirectional based beams). The default beam mode may be a directional beam. For example, when a Type I beam mode is employed, a directional mode for SU-MIMO with single data stream transmission may be utilized. When a Type II beam mode is employed, K directional beams for SU-MIMO may be used, where K<=Kmax is the number of RF chains or analog beams used for transmission (e.g., K=Kmax or K=1).

[0052] The default beam mode selection may follow the rule that for data frames without an explicit beam setup, the default beam mode may be a directional beam. For example, when a Type I beam mode is employed, a directional mode for SU-MIMO with a single data stream transmission may be utilized. When a Type II beam mode is employed, K directional beams for SU-MIMO may be used, where K<=Kmax is the number of RF chains or analog beams used for transmission (e.g., K=Kmax or K=1).

[0053] The default beam mode selection may follow the rule that for data frames with explicit beam setup, the beam mode may follow the beam setup field, which may be carried in one or more of a MIMO setup frame, a multi-channel setup frame, a beacon frame, an assignment field, a schedule element, and / or an extended schedule element, etc.

[0054] A MU-MIMO implementation may be provided. A network entity (e.g., an access point) may group MU-MIMO users, for example, based on beam characterization and / or beam ranking. The beam characterization may include a good beam (e.g., a best beam) and / or a bad beam (e.g., a worst beam). A good beam and a best beam may be used interchangeably. A bad beam and a worst beam may be used interchangeably. The AP may provide beam (e.g., an analog beam) and / or antenna (e.g., a virtual antenna) assignment. Grouping or separation of stations (e.g., stations associated with a user) may be performed in various manners for different transmissions. For example, in DL MU-MIMO transmission, the AP may perform station grouping or separation in the spatial domain. In one example, analog beamforming and / or hybrid beamforming may be applied to group or separate stations. Hybrid beamforming may include analog and digital beamforming techniques. In mmW transmissions (e.g., when hybrid beamforming is applied), one or more techniques may be used to group or separate stations, for example, analog beamforming may be used, analog / digital beamforming may be used, etc.

[0055] Analog beamforming may be used to separate and / or group stations (e.g., stations associated with a user). Beamforming may focus transmissions from a transmitter (e.g., a virtual antenna) so that the transmissions are more directional. Analog beamforming may enable a transmitter to transmit from multiple beams and / or RF chains. An AP / PCP may include one or more antennas (e.g., virtual antennas). A station (e.g., a station associated with a user) may include one or more antennas (e.g., virtual antennas). Using analog beamforming and / or hybrid beamforming, an antenna (e.g., a virtual antenna) may transmit via one or more beams (e.g., analog beams) and / or RF chains.

[0056] The AP / PCP may use inter-user interference information to perform user selection / pairing / grouping. The inter-user interference information may include interference between transmissions to and / or from different stations (e.g., stations associated with a user). Various parameters or metrics may be used to indicate the inter-user interference or the extent of the inter-user interference. For example, a signal-to-noise ratio (SNR) or a signal-to-interference-and-noise ratio (SINR) may be used to characterize the inter-user interference or the extent of the inter-user interference. The inter-user interference information may be obtained in various manners. For example, the inter-user interference information may be obtained by analog beam training, analog beam tracking, and / or analog beam down selection, etc.

[0057] Inter-user interference information may be obtained by analog beam training. During analog beam training (e.g., an extended SLS implementation), a transmitter (e.g., an AP) may send one or more analog transmissions from the transmitter's antennas (e.g., virtual antennas). For example, the analog transmissions may include transmissions via analog beams formed with the virtual antennas.

[0058] The analog transmission may include various signaling. For example, the analog transmission may be a sounding frame or signal. A transmitter's virtual antenna may transmit via one or more analog beams (e.g., transmissions per beam). A receiver (e.g., a station) may receive one or more analog transmissions via the receiver's antenna (e.g., virtual antenna). The receiver's virtual antenna may receive one or more analog transmissions via one or more analog beams. For example, a beam of the station's virtual antenna may receive some or all analog transmissions from the AP. One or more analog transmissions may be communicated from the beam of the AP's virtual antenna to the beam of the station's virtual antenna. The beam of the AP's virtual antenna and the beam of the station's virtual antenna may form a TX and RX beam pair. For example, the beam of the AP's virtual antenna may be the TX beam of the beam. The beam of the station's virtual antenna may be the RX beam of the beam. Different TX and RX beam pairs may be associated with different inter-user interference information. The inter-user interference information may be measured by the station, for example, or may be based on analog transmissions communicated between the TX and RX beams or beam pairs. The AP's virtual antenna and the station's virtual antenna may form a Tx and Rx virtual antenna pair. For example, the AP's virtual antenna may be the TX virtual antenna of the virtual antenna pair. The station's virtual antenna may be the RX virtual antenna of the virtual antenna pair.

[0059] Inter-user interference information may be obtained by analog beam tracking. For example, analog beam tracking may be implemented as a one-to-many sector-level sweep between an AP and a STA, and / or a one-to-one sector-level sweep between an AP and a STA. Analog beam tracking may be implemented as a one-to-many sector-level sweep between STAs, and / or a one-to-one sector-level sweep between a STA and another STA. Analog beam tracking may be part of a MIMO BF training implementation. For example, analog beam tracking may be the SISO phase of extended BF training. During analog beam tracking (e.g., an extended BRP implementation), the AP / PCP may transmit a training sequence one or more times using one or more beams or beam combinations. The training sequence may include one or more analog transmissions via one or more analog beams or beam combinations. The AP / PCP may be configured to track one or more beams or beam combinations. The AP / PCP may determine and / or identify one or more beams or beam combinations to track.

[0060] Inter-user interference information may be obtained by analog beam down-selection. During analog beam down-selection (e.g., in an extended SLS implementation and / or an extended BRP implementation and / or an SLS implementation using BRP frames), the AP / PCP may transmit a training sequence or training frame using one or more beams or beam combinations. The training sequence or training frame may include one or more analog transmissions. The STAs may report feedback (e.g., channel measurements such as SNR and CSI) to the AP / PCP. The AP / PCP may be configured to down-select one or more beams or beam combinations based on the feedback. The AP / PCP may determine and / or identify one or more beams or beam combinations to down-select and / or perform SU / MU-MIMOBF training (e.g., another SU / MU-MIMOBF training).

[0061] The obtained inter-user interference information may be used, for example, by a station, to determine characterization of beams and / or beam pairs. Some beams and / or beam pairs may be characterized as good (e.g., best) beams and / or beam pairs. Some beams and / or beam pairs may be characterized as poor (e.g., worst) beams and / or beam pairs. The inter-user interference information may be used to compare with one or more thresholds (e.g., relatively high thresholds and / or relatively low thresholds) to determine the best and / or worst beams / beam pairs. The inter-user interference information may be used to compare with different inter-user interference information measured based on transmissions via different beams / beam pairs and / or via different antennas / antenna pairs to determine the best and / or worst beams / beam pairs. Beams and / or beam pairs and / or antennas / antenna pairs may be ranked based on the inter-user interference information.

[0062] In one example, an SNR threshold may be used to characterize beams and / or beam pairs. A beam and / or beam pair associated with an SNR equal to or greater than the SNR threshold may be characterized as the best beam and / or beam pair. A beam and / or beam pair associated with an SNR less than the SNR threshold may be characterized as the worst beam and / or beam pair. As described herein, a Tx and Rx virtual antenna pair may include one or more beams and / or beam pairs.

[0063] A beamformee (e.g., a station) may feed back information including or indicative of the best beams and / or beam pairs for (e.g., each) pair of Tx and Rx virtual antennas. A beamformee (e.g., a station) may feed back information including or indicative of the worst beams for (e.g., each) pair of Tx and Rx virtual antennas. For example, a station may feed back the best and / or worst beams to an AP / PCP via an indication. The indication may include or be transmitted via a frame. A beamformee (e.g., a station) may feed back information including or indicative of channel measurements, such as an SNR associated with (e.g., each) triplet <beam ID, Tx antenna ID, Rx antenna ID> and / or a CSI associated with the triplet <beam ID, Tx antenna ID, Rx antenna ID>. For a pair of Tx antenna ID and Rx antenna ID (e.g., a fixed pair or a selected pair), one or more beam IDs associated with the best and / or worst beams may be selected and / or reported. One or more beam IDs may be associated with one or more best and / or worst beams / beam pairs.

[0064] The AP / PCP may receive the indication and / or use the indication to group and / or separate users and / or stations. The implementations described herein may be applicable to one or more stations. For example, the AP / PCP may receive from one station an indication of the AP / PCP's best beam for the station. The AP / PCP's best beam for the station may be identified / selected from multiple beams / pairs of beams for a pair of Tx and Rx virtual antennas. The AP / PCP may receive from another station an indication of the AP's worst beam for that other station for another pair of Tx and Rx virtual antennas. The AP / PCP may determine, based on one or more of the indications for the multiple stations, that the best beam for one station may be among the worst beams for another station. The AP / PCP may determine, based on one or more of the indications for the multiple stations, that the AP / PCP's virtual antenna may include the best beam for one station and that the AP / PCP's other virtual antenna may include the best beam for another station. The AP / PCP may decide to group two stations for transmission (e.g., DL MU-MIMO transmission) and may indicate the grouping to both stations.

[0065] In this example, the AP / PCP may indicate to the stations the respective beam / RF chain / virtual antenna assignments for each station. The AP / PCP may implement the assignments to the stations for DL ​​MU-MIMO transmission. For example, the assignments may be implemented using one or more of the triplet <beam ID, Tx antenna ID, Rx antenna ID>, and (e.g., in addition to) a user ID and / or spatial stream ID, where the assignment of spatial streams to a user may be explicit. For example, the AP / PCP may have four beams / RF chains / virtual antennas (e.g., virtual antennas 1 through 4). The AP / PCP may transmit to user 1 (e.g., station 1 associated with user 1) and user 2 (e.g., station 2 associated with user 2) through DL MU-MIMO. As an example, the AP / PCP may allocate beams / RF chains / virtual antennas 1 and 2 to user 1 based on one or more indications. The AP / PCP may allocate beams / RF chains / virtual antennas 3 and 4 to user 2 based on one or more indications.

[0066] Stations (e.g., stations associated with a user) may be separated by analog / digital beamforming. In analog / digital beamforming techniques, stations (e.g., stations associated with a user) may not be completely separated by analog beams. As an example, the AP / PCP may not require inter-user interference feedback. The AP / PCP may group stations (e.g., stations associated with a user) and / or perform inter-user interference cancellation in the baseband / digital domain. For example, when MU-MIMO transmission impairments may be observed, the AP / PCP may disable MU-MIMO. The AP / PCP may use (e.g., require) partial inter-user interference feedback. The AP / PCP may group stations (e.g., stations associated with a user) based on the partial inter-user interference feedback and / or perform inter-user interference cancellation in the baseband / digital domain.

[0067] The assignment of each beam / RF chain / virtual antenna to each station may be set up, for example, by the AP and / or signaled within the MIMO setup frame and / or other frames (e.g., when the stations are separated by analog beamforming or analog / digital beamforming). For example, the assignment of each beam / RF chain / virtual antenna to each station may be signaled within the MIMO setup frame beam to align the beams / RF chains / virtual antennas on the TX side and the RX side.

[0068] Detailed MU-MIMO user grouping and / or beam / antenna assignment may be described herein. While Figure 9 may refer to specific beams, virtual antennas, and stations, the specific beams, virtual antennas, and stations are for illustrative purposes. The beams, virtual antennas, and stations may be paired in various manners (e.g., depending on the implementation). Any network entity, station, antenna, or virtual antenna may perform an implementation or feature herein (e.g., determining the best or worst beam).

[0069] FIG. 9 illustrates an example of MU-MIMO user selection and / or beam / antenna assignment using analog beam training, tracking, downselection, and / or refinement. The techniques illustrated in FIG. 9 may be implemented using sector-level sweep and / or beam refinement protocols and / or extended versions of the SLS and BPR protocols. In the example of FIG. 9, AP / PCP 902 may include four virtual antennas 906-912 (e.g., PAAs and / or PAAs with multiple polarizations). Each of the virtual antennas 906-912 may form eight analog beams. STA 904 and STA 962 may be potential beamformees. STA 904 may have two virtual antennas 914 and 916. STA 962 may have two virtual antennas 918 and 920. Each of the virtual antennas 914 and 916 may form eight analog beams. Each of the virtual antennas 918 and 920 may form eight analog beams. The implementations and / or structures described herein may be used in one or more examples herein. The implementations and / or structures herein may be extended to any number of virtual antennas and / or stations (e.g., stations associated with a user).

[0070] The AP / PCP 902 may perform analog beam training, tracking, downselection, and / or refinement with one or more STAs (e.g., by sweeping the AP / PCP's transmit analog beam). The AP / PCP 902 may sweep beams on one virtual antenna at a time (e.g., one) in a random order or a preselected order. For example, after the AP / PCP 902 completes sweeping beams on virtual antenna 906, the AP / PCP 902 may sweep beams on virtual antenna 906 and sweep virtual antenna 908. The AP / PCP 902 may sweep beams on virtual antenna 910 and / or virtual antenna 912 (e.g., in a similar manner or a different manner). The order in which the AP / PCP 902 operates through the virtual antennas (e.g., virtual antennas 906-912) may vary. For example, the AP / PCP 902 may sweep eight beams, including beams 922-928. The AP / PCP 902 may transmit multiple analog transmissions via eight beams associated with the virtual antenna 906. The AP / PCP 902 may transmit an analog transmission for each beam. For example, the AP / PCP 902 may transmit an analog transmission via beam 922. The analog transmission may include a sounding signal or a sounding frame. The STA 904 may receive transmissions from beam 922 on the STA 904's virtual antenna 914 and / or virtual antenna 916. For example, the virtual antenna 914 may include eight beams, including beams 938-942. The STA 904 may receive analog transmissions from beam 922 on one, some, or all eight beams of the virtual antenna 914. The STA 904 may measure inter-user interference information of the analog transmissions for the TX and RX beam pair.

[0071] The STA 904 may characterize the TX and RX beam pair based on inter-user interference information measured on analog transmissions received by the STA 904 via the TX and RX beam pair. The STA 904 may characterize the analog transmissions based on the measured inter-user interference information and / or may characterize the TX and RX beam pair based on the characterization of the analog transmissions. For example, the inter-user interference information may include SNR and / or SINR. In the example shown in FIG. 9, the STA 904 may measure the SNR of the transmissions received by the STA 904 via the TX beam 922 and RX beam 938 pair. The STA 904 may characterize the transmissions received by the STA 904 via the TX beam 922 and RX beam 938 pair. The STA 904 may rank the transmissions received by the STA 904 via the TX beam 922 and RX beam 938 pair among the transmissions received by the STA 904 via other TX beam and RX beam pairs. The STA 904 may rank the transmissions received by the STA 904 via the TX beam 922 and RX beam 938 pair among the transmissions received by the STA 904 via beam pairs of the TX beam 922 and other RX beams (e.g., the TX 922 and RX 942 beam pair) on the virtual antenna 914. The STA 904 may rank the analog transmissions received by the STA 904 via the TX beam 922 and RX beam 938 pair among the analog transmissions received by the STA 904 from other beams of the virtual antenna 906, including beams 922-928 (e.g., the TX 928 and RX 938 beam pair). The STA 904 may rank analog transmissions associated with a relatively high SNR or SINR higher than other analog transmissions associated with a relatively low SNR or SINR.

[0072] The STA may characterize a transmission (e.g., an analog transmission) received by the STA via a pair of TX and RX beams as, for example, a best analog transmission or a worst analog transmission based on one or more thresholds of inter-user interference information and / or based on a comparison of inter-user interference information (e.g., between beams or pairs of beams). The STA 904 may receive one or more SNR thresholds or determine one or more pre-configured SNR thresholds to use. In the example shown in FIG. 9, the STA 904 may measure the SNR of the analog transmission received by the STA 904 via the pair of TX beam 922 and RX beam 938. The STA 904 may compare the measured analog transmission with a relatively high SNR threshold received by the STA 904. If the measured analog transmission is higher than the relatively high SNR threshold, the STA 904 may determine that the measured analog transmission is the best analog transmission. The STA 904 may receive a relatively low SNR threshold. The STA 904 may compare the measured analog transmission with the relatively low SNR threshold. If the measured analog transmission is below a relatively low SNR threshold, the STA 904 may determine that the measured analog transmission is the worst case analog transmission.

[0073] The STA may characterize the TX beam, the RX beam, or the TX and RX beam pair as the best beam / beam pair or the worst beam / beam pair based on the characterization of the analog transmission received by the STA via the TX beam, the RX beam, or the TX and RX beam pair. In the example shown in FIG. 9, the STA 904 may receive an analog transmission from beam 922 to the beam at virtual antenna 914. The STA 904 may measure the SNR of the analog transmission on one, some, or all eight beams, including beams 938-942. For example, the STA 904 may measure the SNR of the analog transmission between the TX 922 and RX 938 beam pair (922 / 938 analog transmission) and / or compare the measured SNR to a relatively low SNR threshold. The STA 904 may determine that the measured SNR is below the relatively low SNR threshold and / or determine that the 922 / 938 analog transmission is the worst analog transmission. The STA 904 may measure the SNR of the analog transmission between the TX 924 and RX 942 beam pair (924 / 942 analog transmission) and / or compare the measured SNR to a relatively high SNR threshold. The STA 904 may determine that the measured SNR is higher than the relatively high SNR threshold and / or determine that the 924 / 942 analog transmission is the best analog transmission. The STA 904 may determine that the TX 924 and RX 942 beam pair is the best beam pair based on the determination that the 924 / 942 analog transmission is the best analog transmission. The STA 904 may determine that the TX 924 beam and / or the RX 942 beam are the best beams based on the determination that the 924 / 942 analog transmission is the best analog transmission. The STA 904 may determine that the 922 / 938 analog transmission is the worst beam pair based on the determination that the 922 / 938 analog transmission is the worst analog transmission. The STA 904 may determine that the TX 922 beam and / or the RX 938 beam are the worst beams based on determining that the 922 / 938 analog transmission is the worst analog transmission.

[0074] The STA may associate a best beam / beam pair and / or a worst beam / beam pair determination with a virtual antenna pair. In the example shown in FIG. 9, Tx beam 924 is from virtual Tx antenna 906, and Rx beam 942 is from virtual Rx antenna 914. The STA 904 may determine, based on a best beam pair determination as discussed herein, that the best beam pair for virtual antenna pair 906 and 914 is the TX 924 and RX 942 beam pair. In a similar or the same manner, the STA 904 may determine that the best beam pair for virtual antenna pair 908 and 916 is the TX 932 and RX 940 beam pair.

[0075] For the best and / or worst beam / beam pair, the STA 904 can recognize or identify the AP / PCP, the AP / PCP's virtual antenna, the AP / PCP's virtual antenna beam, the station, the station's virtual antenna, and the station's virtual antenna beam associated with the best and / or worst beam / beam pair, respectively. The AP / PCP, the AP / PCP's virtual antenna, the AP / PCP's virtual antenna beam, the station, the station's virtual antenna, and / or the station's virtual antenna beam may be associated with an index and / or identification. The index and / or identification may be communicated between the AP / PCP and the station, for example, via a frame. For example, the AP / PCP 902 may transmit a sounding frame from the beam 924 of the virtual antenna 906. The sounding frame may include the identification of the beam 924 (e.g., beam ID) and / or the identification of the virtual antenna 906 (e.g., virtual antenna ID). The frame may include an identification by which the AP / PCP can associate with the AP / PCP's TX virtual antenna ID and TX beam ID. The identification by which the AP / PCP can associate with the AP / PCP's TX virtual antenna ID and TX beam ID may be unique. Station 904 may receive a frame (e.g., a sounding frame) via beam 942 on virtual antenna 914. Station 904 may determine that the best analog transmission is associated with the TX 924 and RX 942 beam pair. Station 904 may determine that the best analog transmission is associated with the TX 906 and RX 914 antenna pair. Station 904 may feed back the determination to AP / PCP 902. The feedback information may include (e.g., each) combination and / or set<TxアンテナID、RxアンテナID、RxビームID、RxビームID> The Rx antenna ID and / or Rx beam ID may be implicit.A receiver (e.g., station 904) may determine an Rx antenna ID and / or an Rx beam ID and associate it with a corresponding Tx antenna ID and / or a Tx beam ID.

[0076] A station (e.g., STA 904) may determine the best and / or worst beam / beam pair for other virtual antenna pairs using implementations described herein. In the example shown in FIG. 9, STA 904 may determine that the best TX beam for the pair of TX 908 and RX 914 antennas is beam 930 and that the worst TX beam for the pair of TX 908 and RX 914 antennas is beam 936. STA 904 may determine that the best TX beam for the pair of TX 910 and RX 914 antennas is beam 948 and that the worst TX beam for the pair of TX 910 and RX 914 antennas is beam 944. STA 904 may determine that the best TX beam for the pair of TX 912 and RX 914 antennas is beam 954 and that the worst TX beam for the pair of TX 912 and RX 914 antennas is beam 958. The STA 904 may determine that the best TX beam for the pair of TX 906 and RX 916 antennas is beam 926, and that the worst TX beam for the pair of TX 906 and RX 916 antennas is beam 928. The STA 904 may determine that the best TX beam for the pair of TX 908 and RX 916 antennas is beam 932, and that the worst TX beam for the pair of TX 908 and RX 916 antennas is beam 934. The STA 904 may determine that the best TX beam for the pair of TX 910 and RX 916 antennas is beam 950, and that the worst TX beam for the pair of TX 910 and RX 916 antennas is beam 944. The STA 904 may determine that the best TX beam for the pair of TX 912 and RX 916 antennas is beam 960, and that the worst TX beam for the pair of TX 912 and RX 916 antennas is beam 958. The STA 904 may record and / or store (eg, in volatile or non-volatile memory) one or more of the determinations.

[0077] One or more stations may determine the best and / or worst beam / beam pair for a virtual antenna using the implementations described herein. In the example shown in FIG. 9, STA 962 may determine that beam 924 and beam 932 are not the best TX beams for virtual antenna 918 or virtual antenna 920 (e.g., are among the worst beams). STA 962 may determine that beam 944 and beam 958 are among the best beams for STA 962 (e.g., are the best TX beams). For example, STA 962 may determine that beam 944 is the best TX beam for virtual antenna 918 corresponding to RX beam 964, and that beam 958 is the best TX beam for virtual antenna 920 corresponding to RX beam 966.

[0078] In one or more examples, the AP / PCP may determine the best and / or worst beam / beam pair for a virtual antenna based on inter-user interference information the AP / PCP receives from one or more stations. For example, in FIG. 9, the AP / PCP 902 may receive inter-user interference information for one or more beams / beam pairs for virtual antenna pairs 906 and 914. The AP / PCP 902 may receive the inter-user interference information via a frame. The AP / PCP 902 may receive one or more thresholds for the inter-user interference information. The AP / PCP 902 may determine the one or more thresholds for the inter-user interference information based on a preconfigured designation or indication. The AP / PCP 902 may compare the received inter-user interference information with the thresholds and / or determine the best and / or worst beam / beam pair. The AP / PCP 902 may compare the received inter-user interference information with each other and / or determine the best and / or worst beam / beam pair.

[0079] The AP / PCP may train multiple beams simultaneously, for example, by using multiple virtual antennas simultaneously. The AP / PCP may not sweep all possible analog beams, but may instead sweep a subset of the possible analog beams (e.g., the determined analog beams).

[0080] STA904 may feed back that, for VA2 at STA1, the best beam from AP VA1 is beam x, the best beam from AP VA2 is beam 3, the best beam from AP VA3 is beam x, the best beam from AP VA4 is beam x, and the corresponding SNR / SINR. The information may include that, for VA2 at STA1, the worst beam from AP VA1 is beam x, the worst beam from AP VA2 is beam x, the worst beam from AP VA3 is beam 6, the worst beam from AP VA4 is beam 7, and the corresponding SNR / SINR. For the worst beam, the measurement value (SNR / SINR) may be dominated by noise and / or interference. The measurement value may be reliable or unreliable. In that case, a set of beam indices that may have a measured SNR or SINR below a certain threshold may be fed back. The best beam and / or worst beam may be utilized in one or more examples herein.

[0081] The STA 904 (STA1) may feed back one or more indications (e.g., via a frame) to the AP / PCP 902 indicating the characterization of the beam / beam pair. For example, the STA 904 may feed back an indication to the AP / PCP 902 indicating the best beam / beam pair for a pair of virtual antennas. The STA 904 may feed back an indication including, for example, the following information regarding the reception of an analog beam training frame: The information may include: for virtual antenna 914 (VA1) at STA1, the best beam from virtual antenna 906 (AP VA1) is TX beam 924 (beam 4). The information may include: for virtual antenna 914 (VA1) at STA1, the best beam from virtual antenna 908 (AP VA2) is TX beam 930. The information may include: for virtual antenna 914 (VA1) at STA1, the best beam from virtual antenna 910 (AP VA3) is TX beam 948. The information may include that for virtual antenna 914 (VA1) at STA1, the best beam from virtual antenna 912 (AP VA4) is TX beam 954.

[0082] The STA 904 may feed back an indication to the AP / PCP 902 indicating the worst beam / beam pair for the virtual antenna pair. The information may include that for virtual antenna 914 (VA1) at STA1, the worst beam from virtual antenna 906 (AP VA1) is TX beam 922. The information may include that for virtual antenna 914 (VA1) at STA1, the worst beam from virtual antenna 908 (AP VA2) is TX beam 936. The information may include that for virtual antenna 914 (VA1) at STA1, the worst beam from virtual antenna 910 (AP VA3) is TX beam 944 (beam 6). The information may include that for virtual antenna 914 (VA1) at STA1, the worst beam from virtual antenna 912 (AP VA4) is TX beam 958 (beam 7).

[0083] The information may include the corresponding SNR / SINR for the best and / or worst beam / pair of beams for the virtual antenna pair. The information may include a set of beam indices and / or corresponding measured SNRs or SINRs. For example, the set of beam indices may be a triplet of<TxアンテナID、RxアンテナID、(Tx)ビームID> and / or may include an identification that can be linked (e.g., uniquely linked) to the triplet. Measurements of inter-user interference information may be affected by noise and / or interference. For example, for the worst beam, the measurement (e.g., SNR / SINR) may be dominated by noise and / or interference. In such cases, the measurement may be unreliable. The information may include (e.g., in such cases) a set of beam indices that identify sets of beams and / or pairs of beams. For example, the set of beam indices may be linked (e.g., uniquely linked) to the triplet.<TxアンテナID、RxアンテナID、およびTxビームID> The set of beam indices may include an identification that can be linked (e.g., uniquely linked) to a triplet. For example, the set of beam indices may include a Tx antenna ID, an Rx antenna ID, and a Tx beam ID, or an identification that can be uniquely linked to a triplet having an SNR or SINR measured below a certain threshold (e.g., a relatively low threshold).

[0084] The STA 904 (STA1) may feed back an indication to the AP / PCP 902 (e.g., via a frame) along with one or more of the indications of beam / beam pair characterization for the additional virtual antenna / antenna pair. For example, the STA 904 may indicate the following information regarding, for example, reception of an analog beam training frame: The information may include that for virtual antenna 916 (VA2) at STA1, the best beam from virtual antenna 906 (AP VA1) is TX beam 926. The information may include that for virtual antenna 916 (VA2) at STA1, the best beam from virtual antenna 908 (AP VA2) is TX beam 932. The information may include that for virtual antenna 916 (VA2) at STA1, the best beam from virtual antenna 910 (AP VA3) is TX beam 950. The information may include that for virtual antenna 916 (VA2) at STA1, the best beam from virtual antenna 912 (AP VA4) is TX beam 960.

[0085] The STA 904 may feed back to the AP / PCP 902 an indication of the worst beam / beam pair for the additional virtual antenna / antenna pair. The information may include that for virtual antenna 916 (VA2) at STA1, the worst beam from virtual antenna 906 (AP VA1) is TX beam 928. The information may include that for virtual antenna 916 (VA2) at STA1, the worst beam from virtual antenna 908 (AP VA2) is TX beam 934. The information may include that for virtual antenna 916 (VA2) at STA1, the worst beam from virtual antenna 910 (AP VA3) is TX beam 944 (beam 6). The information may include that for virtual antenna 916 (VA2) at STA1, the worst beam from virtual antenna 912 (AP VA4) is TX beam 958 (beam 7).

[0086] The STA 904 may feed back information about multiple best beams / beam pairs and / or multiple worst beams / beam pairs to the AP / PCP. The information may indicate the number of best beams (e.g., K) and / or the number of worst beams (e.g., N). K and / or N may be set by the AP / PCP in a training frame, a training setup frame, a beacon frame, or other type of control / management frame transmitted by the AP / PCP. One or more of the training frame, training setup frame, beacon frame, or other type of control / management frame transmitted by the AP / PCP may include one or more SNR thresholds. The one or more SNR thresholds may be pre-configured. K and N may be the same or different from each other. K and / or N may be specified explicitly or implicitly in the standard.

[0087] The implementations herein may be for illustrative purposes. Any STA may implement the features herein and / or determine the best beam / beam pair and / or the worst beam / beam pair at a transceiver and / or receiver. The STA may determine that one or more beams / beam pairs for a virtual antenna pair are the best beam / beam pair, or that none of the beams / beam pairs are the best beam / beam pair. The STA may determine that some or all beams / beam pairs for a virtual antenna pair are the worst beam / beam pair, or that none of the beams / beam pairs are the worst beam / beam pair.

[0088] One or more stations may feed back indications to one or more APs / PCPs as described herein. In the example shown in FIG. 9, STA 962 (STA2) may feed back an indication to AP / PCP 902 (e.g., via a frame) along with one or more indications of beam / beam pair characterization for a virtual antenna pair. STA 962 may feed back an indication including the following information, for example, upon receiving an analog beam training frame: The indication fed back by STA2 may be identical or similar (e.g., in format) to the indication fed back by STA2. The indication fed back by STA2 may be based on measurements of STA2. For example, the indication may indicate that beam 4 from AP VA1 and / or beam 3 from AP VA1 are not the best beam for STA2 (e.g., are among the worst beams). The frame may indicate that beam 7 from AP VA3 and / or beam 7 from AP VA4 are among the best beams for STA2 (e.g., are the best beams).

[0089] The configurations and / or implementations herein are for illustrative purposes only. For example, the best TX beam for station 904 and the worst TX beam for station 962 may or may not overlap. If the best TX beam for station 904 and the worst TX beam for station 962 do not overlap, the AP may group or attempt to group station 904 and / or station 962 with a station different from either station 904 or station 962.

[0090] The AP / PCP 902 may receive one or more of the indications herein from STA1 and / or STA2. The AP / PCP 902 may perform user grouping or separation based on one or more of the indications. The AP / PCP 902 may use certain rules and / or processes to group or separate stations (e.g., stations associated with users). The rules and / or processes used may depend on the implementation. For example, the AP / PCP 902 may group stations (e.g., stations associated with users) to minimize inter-user interference. The AP / PCP may pair or group STAs for MU-MIMO transmission. For example, the AP / PCP 902 may group stations with the best beam and / or beam pair. The AP / PCP 902 may group stations with the worst beam and / or beam pair. The AP / PCP 902 may group stations with the best beam and / or beam pair with stations with the worst beam and / or beam pair.

[0091] The AP / PCP 902 may transmit an indication of a grouping of one or more stations (e.g., stations involved in the grouping). The indication of a grouping may include an identification for the station. The indication of a grouping may include an antenna / beam configuration, which may include a triplet for (e.g., each) user / spatial stream.<TxアンテナID、RxアンテナID、TxビームID> The antenna / beam configuration may include a triplet for (e.g., each) user / spatial stream.<TxアンテナID、RxアンテナID、TxビームID> The parameter may include information that may be used to derive the parameter.

[0092] The AP / PCP 902 may perform antenna assignment based on one or more of the indications. In the example shown in FIG. 9, AP VA1 and AP VA2 may comprise the best beams for STA1 (e.g., which may be among the worst beams for STA2), as described herein. AP VA3 and AP VA4 may comprise the best beams for STA2 (e.g., which may be among the worst beams for STA1). The AP / PCP 902 may allocate AP VA1 and AP VA2 to STA1. The AP / PCP may allocate AP VA3 and AP VA4 to STA2. STA1 and / or STA2 may know the corresponding VA to use based on a best beam / beam pair determination as described herein.

[0093] The AP / PCP 902 may perform beam assignment based on one or more of the indications. In the example shown in FIG. 9, AP VA1 and AP VA2 may comprise the best beams, as described herein. For example, beam 4 may have been determined to be the best beam for the AP VA1 / VA1 pair. Beam 3 may have been determined to be the best beam for the AP VA2 / VA2 pair. The AP / PCP 902 may assign beam 4 of AP VA1 to STA1 and / or allocate beam 3 of AP VA2 to STA1. STA1 may know the corresponding beam and / or VA to use based on the best beam / beam pair determination as described herein.

[0094] The AP / PCP 902 may indicate and / or signal beam / antenna assignments to the stations. The grouping indication may include the beam / antenna assignments. For example, the AP / PCP 902 may indicate and / or signal the beam / antenna assignments in a MIMO setup frame or other frame (e.g., to align beams on the TX and RX sides). STA1 and / or STA2 may prepare their corresponding receive antennas / beams. The indication (e.g., a grouping indication) may indicate the beam / antenna assignments. In the example shown in FIG. 9, the beam assignment signaling in this example may include [STA1:VA1, beam 4; VA2, beam 3] and [STA2:VA3, beam 6; VA4, beam 7]. The beam assignment signaling in this example may include [STA1: TxVA1, Tx beam 4, RxVA1; TxVA2, Tx beam 3, RxVA2] and / or [STA2: TxVA3, Tx beam 6, RxVA1; TxVA4, Tx beam 7, RxVA2].

[0095] The specific beam assignment and / or detailed beam index may be omitted in some cases. For example, the AP / PCP and the stations may agree on a certain beam. The beam may be an optimal beam for the AP / PCP and / or the stations in one or more aspects. For example, if the optimal beam is agreed upon between the AP / PCP and STA1 / STA2, the signaling may be [STA1:VA1;VA2] and [STA2:VA3;VA4]. The signaling may use other formats. For example, a bitmap may be used.

[0096] MU-MIMO setup implementations may be provided. Figure 10A may show an example MU-MIMO setup implementation.

[0097] As shown in exemplary FIG. 10A , the STA 1002 (e.g., AP / PCP) may transmit a MU-MIMO setup frame 1004. The MU-MIMO setup frame may be a grant frame depending on the implementation. The MU-MIMO setup frame 1004 may be transmitted in a default multicast control frame transmission mode, such as a single data stream transmission in Type I beam mode or a basic quasi-omni mode or quasi-omni mode for K quasi-omni beams in Type II beam mode. The STA 1014 may prepare to receive the MIMO setup frame 1004 using the default beam mode. Upon receiving a response frame 1016 from the STA 1014, the STA 1002 may poll the STA 1020. The STA 1002 may successfully receive the response frames 1016 and 1022 from the STA 1014 and the STA 1020. The STA 1002 may transmit MU-MIMO PPDUs to the STAs 1014 and 1020 as planned using the signaled beam mode. The STA 1002 may successfully receive response frames from some of the desired stations (e.g., stations associated with the user). The STA 1002 may not successfully receive response frames from all desired stations (e.g., stations associated with the user). For example, the STA 1002 may successfully receive the response frame 1016 from the STA 1014 and / or may not successfully receive the response frame 1022 from the STA 1020. If the STA 1002 does not successfully receive the response frame 1022, one or more schemes may be used.

[0098] The MU-MIMO setup frame 1004 may be transmitted in a default multicast control frame transmission mode with a single data stream transmission. As an example, the frame 1004 may be transmitted using a legacy DMG PPDU. The header field may be detected by a legacy user. A quasi-omnidirectional antenna pattern may be used from the start of the packet to the end of the data portion. For example, in cases where multiple RF front ends / chains may be available on the STA 1002 side, the STA 1002 may transmit the frame 1004 using a (e.g., single) RF chain. Some or all of the RF chains may be utilized. A quasi-omnidirectional beam may be formed by a (e.g., each) RF chain. In one or more examples, the frame 1004 may be transmitted using an EDMG SU PPDU format. For example, the EDGM-Header-B field may not be present in the preamble. The L-STF, legacy long training field (L-LTF), L-Header, and / or EDMG-Header-A field may be transmitted using a single RF chain. The L-STF, L-LTF, L-Header, and / or EDMG-Header-A fields may be transmitted using some or all of the RF chains. Detailed transmission techniques / procedures may be disclosed herein. For the EDMG-STF, EDMG-CE, and data fields, the STA 1002 may transmit the fields using different antenna patterns. For example, the STA 1002 may use multiple RF chains and / or change the digital / baseband domain precoding to support one or more data stream transmissions. The STA 1002 may transmit both the legacy portion and the EDMG portion using the same antenna pattern. The MAC packet carried by the DMG PPDU may be an EDMG MAC packet, and the EDMG MAC packet may be partially understood, for example, by legacy users.

[0099] The MU-MIMO setup frame 1004 may be transmitted in the default multicast control frame transmission mode, with some portions of the frame being transmitted using the MU-directional transmission mode. For example, the STA 1002 may utilize a MU-MIMO transmission beam that may be used for DL ​​MU-MIMO data transmission for the MU-MIMO setup frame. The frame 1004 may be transmitted using a legacy DMG PPDU. The MU-MIMO beam may be used from the beginning of the transmission. The frame 1004 may be transmitted using an EDMG PPDU. The legacy preamble portion (e.g., including the L-STF, L-CEF, L-Header, and / or EDMG-Header-A fields) may be transmitted using the quasi-omnidirectional beam mode. The EDMG portion (e.g., the EDMG-STF, EDMG-CEF, EDMG-Header-B, and / or data fields) may be transmitted using the MU-MIMO beam mode. This mode may allow for single data stream and / or multiple data stream transmission.

[0100] The MU-MIMO setup frame 1004 may be transmitted in a default multicast control frame transmission mode, with the STA 1002 indicating a transmission rule for the following UL response frame in the EDMG MIMO setup MAC frame. For example, the STA 1002 may indicate the antenna / beam mode or analog beam mode expected to be used by the STA 1014 and / or the STA 1020 for the response frame transmission. For example, the STA 1002 may indicate a triplet for (e.g., each) user / spatial stream or similar (e.g., equivalent) information.<TxアンテナID、RxアンテナID、TxビームID> may be carried. When the response frame may be transmitted using the default beam mode, the indication may be omitted. The default beam mode may be signaled by the AP / PCP in a management frame such as a beacon. The default beam mode may be specified by a standard. The STA 1002 may indicate the number of data streams for the response frame. The STA 1002 may indicate the baseband / digital spatial scheme used for the response frame, such as STBC, space frequency block code (SFBC), CSD, open-loop precoding, closed-loop precoding, and / or antenna / polarization selection. The STA 1002 may indicate the modulation and coding scheme for the response frame. The STA 1002 may indicate whether the response frame is polling-based. If the response frame is polling-based, the STA 1002 may indicate whether the response frame (e.g., the first response frame) may be polled by STA1. The STAs (e.g., STA 1014 and STA 1020) may be ordered using an order so that the response frames may be transmitted in different time slots.

[0101] The MU-MIMO setup frame 1004 may be transmitted in a default multicast control frame transmission mode, for example, if a polling frame is present, the STA 1002 indicates a transmission rule for the polling frame (e.g., polling frame 1006) to be transmitted by the STA 1002 within the EDMG MIMO setup MAC frame. For example, the STA 1002 may indicate the beam mode or analog beam mode expected to be used by the STA 1002 for polling frame transmission. When the polling frame may be transmitted using the default beam mode, the indication may be omitted. The default beam mode may be signaled by the AP / PCP (e.g., the STA 1002) in a management frame such as a beacon. The default beam mode may be specified by a standard. The STA 1002 may indicate the baseband / digital spatial scheme to be used for the polling frame (e.g., polling frame 1006), such as STBC, SFBC, CSD, open-loop precoding, closed-loop precoding, and / or antenna / polarization selection. The STA 1002 may indicate the number of data streams for polling frame modulation and / or the coding scheme for the polling frame.

[0102] The MU-MIMO setup frame 1004 may be transmitted in a default multicast control frame transmission mode, and the STA 1002 indicates transmission rules for MU-MIMO transmission to be transmitted by the STA 1002 in an EDMG MIMO setup MAC frame. For example, the EDMG MIMO setup MAC frame may include common fields and / or user-specific fields. The EDMG MIMO setup MAC frame may carry information (e.g., beam / antenna assignment information). The information may include a beam mode or an analog beam mode for DL ​​MU-MIMO transmission. The STA 1002 may indicate the number of beams / RF chains / virtual antennas available to (e.g., each) user. The STA 1002 may indicate the beam / RF chain / virtual antenna index allocated to (e.g., each) user. For example, the STA 1002 may have four RF chains and may transmit to two users (e.g., STA 1014 and STA 1020). STA 1002 may transmit two spatial streams to STA 1014 and one spatial stream to STA 1020. STA 1002 may transmit MU-MIMO transmission 1010 to STA 1014 and MU-MIMO transmission 1008 to STA 1020. In this example, beam / antenna assignment may be explicitly or implicitly performed and / or signaled. STA 1002 may assign two beams / RF chains / virtual antennas to STA 1014 and allocate two beams / RF chains to STA 1020. In the user-specific field for STA 1014, STA 1002 may indicate that Tx Antenna 1, Tx Beam x1 and Tx Antenna 2, Tx Beam y1 pointing to STA 1014 may be used. Corresponding Rx Antenna IDs or expected Rx Antenna IDs for (e.g., each) STA may be indicated explicitly or implicitly.In the user-specific field for STA 1020, STA 1002 may indicate that Tx Antenna 3, Tx Beam x2 and Tx Antenna 4, Tx Beam y2 may be used, pointing to STA 1014. The corresponding or expected Rx Antenna ID for (e.g., each) STA may be indicated explicitly or implicitly.

[0103] Beam / antenna allocation may be implemented unevenly (e.g., for different stations). Transmit power may be distributed equally among users (e.g., two stations associated with a user) by allocating uniform TX power per user. Transmit power may be distributed unevenly among users (e.g., two stations associated with a user) by allocating uniform TX power per beam / antenna. For example, STA1002 may assign three beams / RF chains / virtual antennas to STA1014 and one beam / RF chain to STA1020. In the user-specific field for STA1014, STA1002 may indicate that Tx Antenna 1, Tx Beam x1, Tx Antenna 2, Tx Beam y1, and Tx Antenna 3, Tx Beam z1 pointing at STA1014 may be used. In the user-specific field for STA1020, STA1002 may indicate that Tx Antenna 4, Tx Beam x2 pointing at STA1014 may be used. For example, in the case of unbalanced beam / antenna allocation, a power allocation or power allocation technique may be signaled. In the techniques described herein, a (e.g., one) set of beams / VAs may be allocated to a (e.g., each) user. The STA 1002 may allocate several sets of beams / VAs to a (e.g., each) user (e.g., STA 1014 and STA 1020). The sets of beams may be in order. For example, the first choice may be the first set (e.g., in the order). In cases where the first set may not be successful, the transmitter and / or receiver may move on to the second set, and so on.

[0104] The information may include the baseband / digital spatial scheme to be used for MU-MIMO transmission for (e.g., each) user frame, such as STBC, SFBC, CSD, open-loop precoding, closed-loop precoding, and antenna / polarization selection. Different spatial schemes may be enabled for each user. The information may include the number of data streams per user for MU-MIMO transmission. The information may include per-user modulation and coding schemes for MU-MIMO transmission. The information may include per-user channel bonding / aggregation information.

[0105] The MU-MIMO setup frame may be transmitted in a default multicast control frame transmission mode, and the STA 1002 indicates, for example, in an EDMG MIMO setup MAC frame, the transmission rules for the subsequent uplink (UL) ACK frame 1018 and / or 1024. If antenna reciprocity is assumed, for example, in cases where UL MU-MIMO may be enabled for ACK transmission, the STA 1014 and STA 1020 may use the same beams used for DL ​​MU-MIMO reception.

[0106] For example, in cases where the ACK frames 1018 and / or 1024 may be transmitted one after the other in different time slots, the STAs 1014 and 1020 may use different sets of beams for transmission. The STA 1002 may indicate the beam mode or analog beam mode expected to be used by the STAs 1014 and 1020 for ACK frame transmission. When the ACK frames 1018 and / or 1024 may be transmitted using a default beam mode, the indication may be omitted. The default beam mode may be signaled by the AP / PCP in a management frame such as a beacon. The default beam mode may be specified by a standard. The default mode may be quasi-omnidirectional transmission, or may be directional single data stream transmission, where a directional beam may be trained and / or agreed upon (e.g., in advance).

[0107] The STA 1002 may indicate the number of data streams for the ACK frame (e.g., ACK frame 1018 and / or 1024). When the ACK frame (e.g., ACK frame 1018 and / or 1024) may be transmitted with a default number of data streams, the indication of the number of data streams may be omitted. The STA 1002 may indicate the baseband / digital spatial scheme used for the ACK frame (e.g., ACK frame 1018 and / or 1024), such as STBC, SFBC, CSD, open-loop precoding, closed-loop precoding, and / or antenna / polarization selection. The STA 1002 may indicate the modulation and coding scheme for the ACK frame (e.g., ACK frame 1018 and / or 1024). When the ACK frame may be transmitted at a default MCS level, the indication of the modulation and coding scheme for the ACK frame may be omitted. The STA 1002 may indicate whether the ACK frame is polling-based. If so, the STA 1002 may indicate whether a (e.g., first) ACK frame may be polled by the STA 1002. The STAs (e.g., STAs 1014 and 1020) may be ordered using the order so that ACK frames may be transmitted in different time slots.

[0108] In a MU-MIMO setup implementation, the STA 1014 may prepare to receive the MIMO setup frame 1004 using a default beam mode. Upon receiving the MIMO setup frame 1004, the STA 1014 may acquire knowledge (e.g., recognize), with or without polling, that the STA 1014 may be the first user to send a response frame. The STA 1014 may transmit a response frame 1016 to the STA 1002 using the default beam mode and / or the beam mode assigned by the STA 1002 in the MIMO setup frame 1004. The response frame 1016 may carry information indicating that the STA 1014 may be ready for the subsequent MU-MIMO mode with the beam / antenna assignment indicated by the STA 1002.

[0109] In a MU-MIMO setup implementation, upon receiving the response frame 1016 from the STA 1014, the STA 1002 may poll the STA 1020. The STA 1020 may prepare to receive the MIMO setup frame 1004 and the poll frame 1006 using a default beam mode. Upon receiving the MIMO setup frame 1004, the STA 1020 may acquire knowledge (e.g., recognize) that the STA 1020 may be the second user to transmit a response frame 1022, with or without polling. Upon receiving the poll frame 1012, the STA 1020 may transmit a response frame 1022 to the STA 1002 using the default beam mode or the beam mode allocated by the STA 1002 in the MIMO setup frame 1004. The response frame 1022 may carry information indicating that the STA 1020 may be ready for the subsequent MU-MIMO mode with the beam / antenna assignment indicated by the STA 1002.

[0110] In some cases of MU-MIMO setup implementation, STA 1002 may successfully receive response frames 1016 and 1022 from STA 1014 and STA 1020, respectively. STA 1002 may transmit MU-MIMO PPDUs to STA 1014 and STA 1020 as planned using the signaled beam mode.

[0111] In some cases of MU-MIMO setup implementation, the STA 1002 may successfully receive response frames from some of the stations (e.g., desired users or stations associated with users). The STA 1002 may not successfully receive response frames from all of the desired users. In this example, the STA 1002 may receive (e.g., only receive) the response frame from the STA 1014. The STA 1002 may use one or more of a partial transmission impairment scheme (e.g., as shown in FIG. 10B) or a transmission impairment scheme (e.g., as shown in FIG. 10C). Various techniques may be used for the partial transmission impairment scheme (e.g., as shown in FIG. 10B). In one technique, the STA 1002 may transmit a MIMO end frame 1026 using a beam mode for the STA 1014. After the xIFS period, as shown in FIG. 10B, the STA 1002 may transmit another MIMO end frame 1028 using the default mode or quasi-omni mode to end the current MU-MIMO transmission opportunity (TXOP). In one approach, the STA 1014 may respond with an ACK frame for the directional MIMO end frame 1026 transmission. The STA 1002 may transmit the MIMO end frame 1028, for example, after the xIFS. In one approach, the quasi-omni MIMO end frame 1028 may be omitted.

[0112] In a transmission failure scheme (e.g., as shown in FIG. 10C), the STA 1002 may continue transmission (e.g., MU-MIMO transmission 1030). The STA 1002 may use (e.g., may only use) the beam / antenna pointing at the STA 1014. The STA 1002 may allocate power (e.g., full power) to a subset of users (e.g., the STA 1014). The STA 1014 may respond with an ACK frame 1032, as shown in FIG. 10C.

[0113] In some cases of MU-MIMO setup implementations, the STA 1002 may not receive a response frame (e.g., any response frame) from a potential MU-MIMO user or a station associated with the user (e.g., all of the users or stations). The STA 1002 may terminate the MU-MIMO TXOP by transmitting a MIMO termination frame.

[0114] A SU-MIMO setup implementation may be provided. The SU-MIMO setup implementation may be shown in FIG. 11. The scheme may be considered as an exemplary MU-MIMO setup with (e.g., one) user. As shown in the exemplary FIG. 11, a STA 1110 (e.g., an AP / PCP) may transmit a MU-MIMO setup frame 1102. The MU-MIMO setup frame 1102 may be transmitted in a default multicast control frame transmission mode, such as a single data stream transmission in a Type I beam mode or a basic quasi-omni mode or a quasi-omni mode for K quasi-omni beams in a Type II beam mode. The STA 1112 may prepare to receive the MIMO setup frame 1102 using the default beam mode. Upon receiving a response frame 1016 from the STA 1112, the STA 1110 may transmit a MU-MIMO 1104 and receive an ACK frame 1108.

[0115] Training / tracking may be performed as part of and / or in conjunction with a MIMO setup implementation. A MIMO setup frame may be added to a sounding sequence (e.g., an additional sounding sequence). For example, the MIMO setup implementation may be for channel access with a MIMO setup frame. Training / tracking may include additional training / tracking. Additional training / tracking may achieve additional training. Implementations herein may apply to SU-MIMO and / or MU-MIMO.

[0116] As an example, the sounding sequence may be used for baseband / digital BF / MIMO mode adaptation / selection. For example, a MIMO setup frame may be transmitted using a quasi-omnidirectional mode with a single data stream. The CEF field (including the L-CEF and EDMG-CEF fields) may be designed and / or used for single data stream estimation. The TXOP holder / initiator of a MIMO transmission may want to know full or partial information about the effective MIMO channel after analog beamforming. The TXOP holder / initiator of a MIMO transmission may obtain full or partial information about the effective MIMO channel, for example, by appending an additional known training sequence to the end of the PPDU transmission. The Tx and / or Rx may use the trained analog beam. The responder (e.g., a receiver such as a station) may use the training sequence (e.g., an additional known training sequence) to estimate the baseband MIMO channel and / or feedback information requested by the initiator (e.g., a transmitter such as an AP). Using the fed back information, the initiator may determine the baseband / digital MIMO / BF mode. The MIMO response frame may be used to carry baseband channel state information (CSI) feedback. Baseband BF / MIMO training may be combined with MIMO setup implementation and / or improve system efficiency.

[0117] As an example of a MIMO setup implementation with additional training / tracking, a sounding sequence (e.g., an additional sounding sequence) may be used for analog beam tracking / improvement. For example, a MIMO setup frame may be transmitted using a quasi-omni mode with a single data stream. The CEF field (including the L-CEF and EDMG-CEF fields) may be designed and / or used for single data stream estimation. The TXOP holder / initiator may recognize that the transmit beam, the receive beam, or both may not be sufficiently good. For example, transmissions via the transmit beam, the receive beam, or both may not meet certain quality criteria. The TXOP holder / initiator may decide to perform beam tracking / improvement during MIMO setup implementation. The additional training sequence may be used to transmit beam training, receive beam training, or transmit / receive beam training. A responder (e.g., a receiver such as a station) may use the additional training sequence to determine good and / or bad beams for the transmitter and / or receiver. With the determination of good and / or bad beams, the initiator (e.g., a transmitter such as an AP) and the responder (e.g., a receiver such as a station) may update the analog beams. An example of a MIMO setup implementation with additional training may be described herein (e.g., as shown in FIG. 12). An example of a MIMO setup implementation with additional training may include one or more of the following:

[0118] As shown in FIG. 12, an example of a MIMO setup implementation with additional training may include a STA 1220 (e.g., an AP / PCP) transmitting a MIMO setup frame 1204 (e.g., a MU-MIMO setup frame or a SU-MIMO setup frame). The transmission of the MIMO setup frame 1204 may include a PLCP header 1202. The additional training field may carry multiple training sequences (e.g., training sequence 1206, training sequence 1208, and / or training sequence 1212). The training sequences may be transmitted using mutually different antenna / beam patterns. The training sequence may be repeated and / or transmitted using an antenna pattern (e.g., a fixed antenna / beam pattern). The receiver may sweep the receiver's antenna / beam pattern and train one or more receive beams. The length of the training field (e.g., the additional training field) may extend from the PLCP header 1202 or a portion of the PLCP header 1202 to the end of the training sequence (e.g., training sequence 1208). The training purpose and / or feedback request may be carried in the MAC body of the MIMO setup frame. In another embodiment, the training purpose and / or feedback request may be carried in the PLCP header. As an example, the frame 1204 may be transmitted using a legacy DMG PPDU. The header field may be detected by a legacy user. A quasi-omnidirectional antenna pattern may be used from the start of the packet to the end of the training sequence. A packet type field in the header may be used to indicate that the packet may be appended with a TRN field (e.g., the TRN field may be appended after the data portion). A value N in the training length field may indicate the length of the TRN field 1224. As an example, the frame may be transmitted using an EDMG SU PPDU format. For example, the EDGM-Header-B field may not be present in the preamble.In the legacy header (L-header) field, the packet type and / or training length fields may be set to indicate the presence of a TRN-T field at the end of the packet. The L-STF, L-LTF, L-Header, and / or EDMG-Header-A fields may be transmitted using a (e.g., single) RF chain. The L-STF, L-LTF, L-Header, and / or EDMG-Header-A fields may be transmitted using some or all of the RF chains. Transmission techniques (e.g., as described herein) may be used.

[0119] As an example, the PLCP header 1204 may include an L-header. In the L-header, a packet type field may be used to indicate that a packet may have a TRN field attached (e.g., the TRN field may be attached after the data portion). A value N in a training length field may indicate the length of the TRN field.

[0120] An example of a PLCP header 1204 may be EDMG-Header-A. In EDMG-Header-A, EDMG-Header-A may indicate / include a use immediately field. The use immediately field may be used to indicate whether a MIMO transmission (e.g., a MIMO transmission immediately after a MIMO setup exchange) may use an updated analog / baseband beam or scheme, e.g., an updated analog / baseband beam or scheme derived from training using an additional training field appended after the MIMO setup frame. For example, in cases where the transmitter / receiver may not have enough time to use the updated beam or scheme, the use immediately field may be set to 0. The training results may be used in a later transmission.

[0121] The EDMG-Header-A may indicate / include the purpose of the additional training field (e.g., EDMG-Header-A). The purpose of the additional training field may include baseband MIMO channel sounding and / or analog beam tracking / refinement, etc. When used for analog beam tracking / refinement, the additional training field may be used for Tx training, such as Tx sweeping (e.g., for Tx training only), and / or to train different beams. The additional training field may be used for Rx training (e.g., for Rx training only). The Tx beam may be used (e.g., fixed) and / or repeated for a certain length, allowing the Rx to sweep its beam. When used for analog beam tracking / refinement, the additional training field may be used for a combination of Tx and Rx training. The order in which Tx and / or Rx training may be specified. For example, Tx training may be performed first, followed by Rx training. Rx training may be performed first, followed by Tx training. For example, if an unequal number of Tx / Rx trainings may be applied, the number of Tx / Rx trainings may be specified, e.g., N1 sequences for Tx training followed by N2 sequences for Rx training.

[0122] The EDMG-Header-A may indicate / include a feedback type. The feedback type may include limited channel state information feedback, such as average SNR / SINR feedback per Tx / Rx antenna pair. For example, when the STA 1220 plans to perform baseband / digital domain transmit / receive beam / polarization selection, the STA 1220 may request average SNR or SINR feedback. The feedback type may include full channel state information feedback per Tx / Rx antenna pair. For example, when the STA 1220 plans to perform closed-loop precoding, the STA 1220 may request full CSI feedback.

[0123] The EDMG-Header-A may indicate / include a channel feedback resolution (e.g., channel feedback resolution per Tx / Rx antenna pair). The channel feedback resolution may indicate a quantification level of the feedback. For example, the channel feedback resolution may indicate (e.g., define) the number of bits to represent a real / complex value depending on the feedback type. The real / complex value may be an SNR / SINR value or an average of the SNR / SINR values. The real / complex value may include a delay, a time-domain tap magnitude, and / or a time-domain tap phase, etc.

[0124] The transmission of the MIMO setup frame may include a MAC packet. The MAC packet may include an EDMG MAC packet. In some scenarios, for example, the MAC packet may be carried by a DMG PPDU. The EDMG MAC packet may be partially understood by legacy users. The EDMG MAC packet may carry MIMO setup information (e.g., as described herein). The EDMG MAC packet may carry information about baseband BF training configuration requirements. The information about baseband BF training configuration requirements may include an immediate use field. The immediate use field may be identical to that used in the EDMG-Header-A field. The information about baseband BF training configuration requirements, including the immediate use field information, may be carried in the PLCP header and / or the MAC packet. The information about baseband BF training configuration requirements may include the purpose of additional training fields. A field indicating the purpose of the additional training fields may be carried (e.g., along with other fields) in the EDMG-Header-A field and / or the MAC body.

[0125] The immediate use field may indicate / include a channel feedback resolution (e.g., channel feedback resolution per Tx / Rx antenna pair). The channel feedback resolution may indicate a quantification level of the feedback. For example, the channel feedback resolution may indicate (e.g., define) the number of bits to represent a real / complex value depending on the feedback type. The real / complex value may be an SNR / SINR value or an average of the SNR / SINR values. The real / complex value may include a delay, a time-domain tap magnitude, and / or a time-domain tap phase, etc.

[0126] Information about baseband BF training configuration requirements, including the purpose of additional training fields, may be carried in the PLCP header and / or MAC packet. The information about baseband BF training configuration requirements may include a channel feedback type. The feedback type may be the same as that used in the EDMG-Header-A field. The channel feedback type may indicate / include a channel feedback resolution (e.g., channel feedback resolution per Tx / Rx antenna pair). The channel feedback resolution may indicate a quantification level of the feedback. For example, the channel feedback resolution may indicate (e.g., define) the number of bits to represent a real / complex value depending on the feedback type. The real / complex value may be an SNR / SINR value or an average of the SNR / SINR values. The real / complex value may include a delay, a time-domain tap strength, and / or a time-domain tap phase, etc.

[0127] Information about baseband BF training configuration requirements, including channel feedback type information, may be carried in the PLCP header and / or MAC packet. The information about baseband BF training configuration requirements may include channel feedback resolution per Tx / Rx antenna pair. This field may be the same as that used in the EDMG-Header-A field. The channel feedback resolution per Tx / Rx antenna pair may indicate / include the channel feedback resolution (e.g., channel feedback resolution per Tx / Rx antenna pair). The channel feedback resolution may indicate a quantification level of the feedback. For example, the channel feedback resolution may indicate (e.g., define) the number of bits to represent a real / complex value depending on the feedback type. The real / complex value may be an SNR / SINR value or an average of the SNR / SINR values. The real / complex value may include a delay, a time-domain tap strength, and / or a time-domain tap phase, etc. Information about baseband BF training configuration requirements, including the channel feedback resolution per Tx / Rx antenna pair, may be carried in the PLCP header and / or MAC packet.

[0128] The transmission of the MIMO setup frame may include a training sequence (e.g., an additional training field). In the additional training field, the STA 1220 may transmit the training sequence, for example, using the antenna and beam to be trained. As an example, the additional training field may be appended immediately after the MAC packet. In one or more of the examples herein, the additional training field may be transmitted xIFS time after the end of the EDMG MAC packet transmission to give the beamformee (e.g., STA 1222 in this example) more processing time to acquire the TX antenna and beam to be used.

[0129] An example of a MIMO setup implementation with additional training may include the STA 1222 transmitting a response frame 1210. The STA 1222 may convey feedback information requested by the STA 1220 (e.g., in the response frame 1210). The STA 1222 may implement a MIMO setup implementation (e.g., a MIMO setup implementation described herein). The STA 1222 may transmit an ACK / BA 1218. The TX / RX antennas may be returned to default mode.

[0130] An example of a MIMO setup implementation with additional training may include, for example, if the immediate use field is set, the STA 1220 may perform MIMO transmission 1216 using information updated by the feedback. The STA 1220 may use the beam and / or transmission scheme signaled (e.g., explicitly signaled) by the MIMO setup frame 1204.

[0131] In an example of a MIMO setup implementation with additional training, additional training fields may be attached to the MIMO setup frame. The example of a MIMO setup implementation with additional training may be extended to a more general case. For example, in any Beam Improvement Protocol (BRP) or extended BRP frame, additional training fields may be attached for the same or similar purposes, such as baseband full / partial CSI sounding, analog beam tracking / improvement, etc. The signaling described herein may be carried in one or more of the PLCP header, the BRP or eBRP MAC packet, or the MAC header of the BRP or eBRP frame.

[0132] The MIMO setup frame may include various fields. The MIMO setup frame may include common fields and / or user-specific fields. In a SU-MIMO setup, a user-specific field (e.g., one) may be present. The MIMO setup frame may include one or more fields indicating one or more of the following: Tx / Rx ID, the expected Nss for (e.g., each) user in the subsequent MIMO data transmission, the analog beam pattern to be used in the MIMO transmission, the expected response frame setup from the STA, the baseband MIMO type to be used in the MIMO transmission, and / or other information if additional training fields are attached. The field used to indicate the analog beam pattern to be used in the MIMO transmission may indicate or include one or more PAA information / indexes, polarization information / indexes, analog beam indexes, or other beam candidates. The field used to indicate the baseband MIMO type to be used in the MIMO transmission may indicate or include one or more of antenna / PAA / polarization selection, a selected index, an STBC-like scheme (e.g., SFBC), dual-carrier modulation, or space / frequency / time-domain dual-carrier modulation, or closed-loop (CL) precoding, or open-loop (OL) precoding. The selected index may be signaled, for example, prior to the MIMO transmission. The field used to set up expected response frames from the STA may indicate or include one or more response frames for the MIMO setup frame or an ACK frame for the MIMO transmission. Other information, in case additional training fields may be attached, may indicate or include one or more immediate use fields, the purpose of the additional training fields, the channel feedback type, or the channel feedback resolution.

[0133] When multiple streams containing the same legacy fields (e.g., legacy short training field (STF), channel estimation field (CEF), and header) are transmitted from multiple antennas, unintended beamforming may occur with respect to the received signals due to strong correlation between the transmitted signals. Fluctuations in received signal power may cause suboptimal AGC settings for decoding the legacy header in legacy devices. For example, different cyclic shifts may be applied to the transmitted signals to decorrelate the transmitted signals. Applying different cyclic shifts to the transmitted signals may be compatible with cyclic prefix (CP)-OFDM transmission.

[0134] A MIMO transmission implementation for the preamble may be used, for example, to reduce unintentional beamforming. Several techniques may be provided for single-carrier waveforms, such as linear shifting and block-based circular shifting. A selection of techniques (e.g., as shown in Figures 13A-13C) may enable interference-free channel estimation for legacy devices.

[0135] For example, for linear shifting, the transmitter may intentionally shift spatial streams transmitted through different antennas. Single-carrier waveforms (e.g., during linear shifting) may not align at the receiver and / or unintentional beamforming may be avoided. The transmitter may apply block-based cyclic shifting. For example, legacy fields of a PPDU may be cyclically shifted. One or more legacy fields (e.g., as described herein) may be or may include pre-EDMG modulation fields. The pre-EDMG modulation fields may include a legacy STF field, a legacy CEF field, and a header. A cyclic shift may be applied to grouped STFs, CEFs, and / or headers. In one or more examples herein, a cyclic shift may be applied to a specific group of fields or subfields (e.g., a specific Golay sequence). For example, as shown in FIG. 13, a spatial stream 1326 may include a short training field 1302, a channel estimation field 1306, a header 1308, and other 11ay fields 1310. Spatial stream 1328 may include a short training field 1312, a channel estimation field 1314, a header 1316, and other 11-day fields 1318. Spatial stream 1328 may include a short training field 1312, a channel estimation field 1314, a header 1316, and other 11-day fields 1318. Spatial stream 1330 may include a short training field 1319, a channel estimation field 1320, a header 1322, and other 11-day fields 1324. Figure 13A may show an example of linear shifting. Spatial stream 1326 may be linearly shifted from spatial stream 1328 (e.g., as shown at 1332). Spatial stream 1328 may be linearly shifted from spatial stream 1330 (e.g., as shown at 1334).

[0136] The transmitter may apply a block-based cyclic shift. For example, legacy fields of the PPDU may be cyclically shifted. The STF, CEF, and / or header may be grouped, and / or the cyclic shift may be applied to the group. The cyclic shift may be applied to the grouped STF, CEF, and / or header. In one or more examples herein, the cyclic shift may be applied to a selected (e.g., specific) group of fields or subfields (e.g., Golay sequences). The grouping may consider one or more of an STF that excludes a Golay sequence at the end of the STF (e.g., -Ga128), a CEF that includes a Golay sequence at the end of the STF (e.g., -Ga128), or a header. As shown in FIG. 13B, the grouping may consider an STF that excludes a Golay sequence at the end of the STF (e.g., -Ga128). For spatial stream 1328, a block shift of the STF that excludes a Golay sequence at the end of the STF (e.g., -Ga128) may be indicated by block cyclic shift 1332. For spatial stream 1330, a block shift of the STF that excludes a Golay sequence at the end of the STF (e.g., -Ga128) may be indicated by block circular shift 1338. As shown in FIG. 13B, the grouping may also consider a CEF that includes a Golay sequence at the end of the STF (e.g., -Ga128). For spatial stream 1328, a block shift of the CEF that includes a Golay sequence at the end of the STF (e.g., -Ga128) may be indicated by block circular shift 1334. For spatial stream 1330, a block shift of the CEF that includes a Golay sequence at the end of the STF (e.g., -Ga128) may be indicated by block circular shift 1340. As shown in FIG. 13B, the grouping may also consider a header. For spatial stream 1328, a block shift of the header may be indicated by block circular shift 1336. For spatial stream 1330, a block shift of the header may be indicated by block circular shift 1342.

[0137] Block-based shifting may take into account subfields and the purpose of the subfields. Figure 13C may show an example of block-based shifting that takes into account the purpose of the subfields. For spatial stream 1328, block shift 1344 may take into account the purpose of subfields 1312-1316. For spatial stream 1330, block shift 1346 may take into account the purpose of subfields 1319-1322. Technique options for avoiding unintentional beamforming block-based shifting (e.g., as shown in Figure 15B) may enable interference-free channel estimation for legacy devices.

[0138] A cyclic CEF may be used for multiple streams (e.g., stream 1402 and stream 1404). In IEEE 802.11ad, a sequence within the CEF may introduce a property zero autocorrelation zone, which may enable channel estimation in the time domain via a correlation operation, as shown in FIG. 14. As shown in FIG. 14, two streams, stream 1402 and stream 1404, may share a zero correlation zone 1420. Stream 1404 may include a short training field 1422, a channel estimation field 1424, and a -Gb 128 1412. The -Gb 128 1412 may be used as protection. The short training field 1422 may include several -Gb 128s, including -Gb 128 1406. The channel estimation field 1424 may include several Gb 128s and -Gb 128s (e.g., Gb 128 1416). Stream 1404 may include a zero autocorrelation zone 1420. Stream 1402 may include several Ga 128s and -Gb 128s (e.g., -Gb 128 1408), including several Ga 128s and -Gb 128s that fall within the zero autocorrelation zone 1420. The zero autocorrelation zone 1420 may include Ga 128s 1410. Stream 1402 may lag behind stream 1404, as indicated by lag 1414.

[0139] As shown in graph 1426, the x-axis refers to lag and the y-axis refers to energy. In one embodiment, the y-axis may refer to correlation. Along the x-axis between stream 1402 and stream 1404, the energy remains low (towards or at zero energy), exhibiting a zero autocorrelation zone 1428.

[0140] As an example, a zero correlation zone (e.g., 1506 for stream 1502 and 1516 for stream 1504) may be shared with multiple streams (e.g., stream 1502 and stream 1504) to enable channel estimation for different streams (e.g., stream 1502 and stream 1504). For example, two orthogonal CEFs may be generated by circularly shifting the original CEF of 802.11ad or any other sequence with a zero autocorrelation zone, including a sequence with an all-zero autocorrelation zone (e.g., a Zadoff-Chu sequence). Orthogonal CEFs may be generated when the shifts (e.g., circular shifts 1510 and 1512) are at least −64 and +64, as shown in FIG. 15A. FIG. 15B may show various auto / cross-correlation results, for example, based on the implementation of FIG. 15A.

[0141] Because sequences 1502 and 1504 are derived from original sequences 1402 and 1404 by using circular or linear shifts, sequences 1502 and 1504 may maintain the same zero autocorrelation zones as shown in FIG. 14. For example, zero autocorrelation zone 1420 is identical to zero autocorrelation zone 1506. Sequences 1502 and 1504 may be mutually orthogonal to each other (e.g., +-64 sample shift). Similar techniques may be extended for multi-beam training purposes, for example, by introducing smaller circular shift values.

[0142] A tiered implementation may be used for multi-stream support. A tiered implementation may be used to establish transmission and / or reception of multiple data streams between multiple STAs, such as a pair of STAs, e.g., an EDMGAP / PCP and an EDMG STA, or two EDMG STAs. The pair of STAs may include an EDMGAP / PCP and an EDMG STA, or two EDMG STAs. An example of a tiered implementation may include one or more of the following:

[0143] A phased implementation may comprise a STA, for example, an EDMG AP / PCP or an EDMG STA, that may conduct an initial transmission with another STA using a quasi-omni-directional beam.

[0144] The phased implementation may include that after the initial quasi-omnidirectional transmission, the pair of STAs may proceed to perform beam training, e.g., using SLS or BRP. During SLR and BRP, one or more TX sectors and / or one or more RX sectors may be selected. If the STA is equipped with multiple PAAs, the STA may simultaneously perform SLS and / or BRP using different PAAs. The SLS and / or BRP pattern may be such that different PAAs on the transmitting STA may not overlap in beams (e.g., the coverage of the beams may not overlap), and different PAAs on the receiving STA may not overlap in beams. The different PAAs on the transmitting STA may transmit using orthogonal signaling, such as using orthogonal codes or sets of subcarriers. The orthogonal signaling may carry the identity of the different PAAs. The receiving STA may use the different PAAs to decode the orthogonal signaling and / or identify the transmitting PAA from which the received signal is received. Using simultaneous transmission and / or reception between multiple PAAs, multiple STAs (e.g., pairs of STAs) may select one or more Tx sectors and one or more Rx sectors that may be associated with one or more PAAs on the transmitting and receiving STAs. A set of Tx sectors and Rx sectors that may be associated with multiple PAAs may be used to establish MIMO transmissions between multiple (e.g., pairs of STAs).

[0145] The phased implementation may include that when one or more Tx and Rx sectors, which may be associated with different PAAs on a pair of STAs, are selected, a STA (e.g., one of the STAs), e.g., an EDMG AP / PCP or an EDMG STA, may request a larger number of data streams. For one or more Tx / Rx sector pairs, e.g., to transmit a larger number of streams using one or more Tx / Rx sector pairs, the STA may request polarization training. The requesting STA may indicate a requested polarization type, such as circular, linear, mixed, vertical, horizontal, etc. The requesting STA may express the requested polarization type, e.g., using Euler angles relative to a (e.g., existing) polarization or coordinate system. The requesting STA (e.g., a transmitter such as an AP) and the responding STA (e.g., a receiver such as an STA) may perform polarization training for the requested polarization type. The responding STA may provide feedback on the polarization training. The requesting STA may request a polarization mode change. The requesting STA may request a polarization mode change by adding an additional stream. For example, to provide a larger number of data streams using the same Tx / Rx sector pair, additional streams may be transmitted using different polarization types.

[0146] A tiered implementation may include that if a requesting STA uses a higher / lower data rate, the requesting STA may request to use a wider / narrower channel bandwidth, e.g., more or fewer subcarriers. If the responding STA is capable of wider channel transmission, the responding STA may respond affirmatively. Multiple STAs (e.g., pairs of STAs) may then use the wider or narrower channel for one or more of the Tx / Rx sectors.

[0147] Although features and elements of the present invention are described in particular combinations in preferred embodiments, each feature or element may be used alone without other features and elements of the preferred embodiments, or in various combinations with or without other features and elements of the present invention. It should be understood that while the solutions described herein consider 802.11 specific protocols, the solutions described herein are not limited to this scenario and are applicable to other wireless systems.

[0148] 16A illustrates exemplary wireless local area network (WLAN) devices. One or more of the devices may be used to implement one or more of the features described herein. The WLAN may include, but is not limited to, an access point (AP) 102, stations (STAs) 110, and STAs 112. The STAs 110 and 112 may be associated with the AP 102. The WLAN may be configured to implement one or more protocols of the IEEE 802.11 communications standard, which may include channel access schemes such as DSSS, OFDM, OFDMA, etc. The WLAN may operate in a mode, e.g., infrastructure mode, ad hoc mode, etc.

[0149] A WLAN operating in infrastructure mode may comprise one or more APs that communicate with one or more associated STAs. The APs and the STAs associated with the APs may comprise a basic service set (BSS). For example, AP 102, STA 110, and STA 112 may comprise BSS 122. An extended service set (ESS) may comprise one or more APs (comprising one or more BSSs) and the STAs associated with the APs. The APs may have access to and / or interface with a distribution system (DS) 116. The DS 116 may be wired and / or wireless and may carry traffic to and / or from the APs. Traffic originating from outside the WLAN to a STA within the WLAN may be received at an AP within the WLAN, and the AP may transmit the traffic to the STA within the WLAN. Traffic originating from a STA within the WLAN to a destination outside the WLAN, e.g., server 118, may be transmitted to an AP within the WLAN, and the AP may transmit the traffic to the destination, e.g., via the DS 116 to the network 114, for transmission to the server 118. Traffic between STAs within a WLAN may be transmitted through one or more APs. For example, a source STA (e.g., STA 110) may have traffic for a destination STA (e.g., STA 112). STA 110 may transmit traffic to AP 102, and AP 102 may transmit traffic to STA 112.

[0150] A WLAN may operate in ad-hoc mode. An ad-hoc mode WLAN may be referred to as an Independent Basic Service Set (IBBS). In an ad-hoc mode WLAN, STAs may communicate directly with each other (e.g., STA 110 may communicate with STA 112 without such communication being routed through an AP).

[0151] IEEE 802.11 devices (e.g., IEEE 802.11 APs in a BSS) may use beacon frames to announce the presence of a WLAN network. An AP, such as AP 102, may transmit beacons on a channel, e.g., a fixed channel, such as a primary channel. STAs may use a channel, such as the primary channel, to establish a connection with the AP.

[0152] The STA and / or AP may use a carrier sense multiple access with collision avoidance (CSMA / CA) channel access mechanism. In CSMA / CA, the STA and / or AP may sense the primary channel. For example, if the STA has data to transmit, the STA may sense the primary channel. If the primary channel is detected as busy, the STA may back off. For example, a WLAN or portion thereof may be configured so that one STA may transmit at a given time, e.g., in a given BSS. Channel access may include RTS and / or CTS signaling. For example, an exchange of request to send (RTS) frames may be sent by the transmitting device and clear to send (CTS) frames may be sent by the receiving device. For example, if the AP has data to send to the STA, the AP may send an RTS frame to the STA. If the STA is ready to receive the data, the STA may respond with a CTS frame. The CTS frame may include a time value that may alert other STAs to postpone accessing the medium while the AP initiating the RTS may transmit its data. Upon receiving a CTS frame from the STA, the AP may transmit data to the STA.

[0153] Devices may reserve spectrum via a network allocation vector (NAV) field. For example, in an IEEE 802.11 frame, the NAV field may be used to reserve a channel for a time slot. A STA wishing to transmit data may set its NAV at a time when it may expect to use the channel. When a STA sets its NAV, the NAV may be set for the associated WLAN or a subset thereof (e.g., a BSS). Other STAs may count down their NAV to 0. When the counter reaches the value zero, the NAV function may indicate to other STAs that the channel is available at that time.

[0154] A device in a WLAN, such as an AP or STA, may include one or more of a processor, memory, a radio receiver and / or transmitter (e.g., which may be combined as a transceiver), one or more antennas (e.g., antenna 106 of FIG. 16A ), etc. The processor function may comprise one or more processors. For example, the processor may comprise one or more of a general-purpose processor, a special-purpose processor (e.g., a baseband processor, a MAC processor, etc.), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. One or more processors may be integrated or unintegrated with each other. A processor (e.g., one or more processors or a subset thereof) may be integrated with one or more other functions (e.g., other functions, such as memory). A processor may perform signal coding, data processing, power control, input / output processing, modulation, demodulation, and / or any other function that may enable a device to operate in a wireless environment, such as the WLAN of FIG. 16A . A processor may be configured to execute processor-executable code (e.g., instructions), including, for example, software and / or firmware instructions. For example, a processor may be configured to execute computer-readable instructions contained on one or more of the processor (e.g., a chipset including a memory and a processor) or memories. Execution of the instructions may cause the device to perform one or more of the functions described herein.

[0155] The device may include one or more antennas. The device may utilize multiple-input multiple-output (MIMO) techniques. The one or more antennas may receive wireless signals. The processor may receive wireless signals, for example, via one or more antennas. The one or more antennas may transmit wireless signals (e.g., based on signals transmitted from the processor).

[0156] A device may have memory, which may include one or more devices for storing programming and / or data, such as processor-executable code or instructions (e.g., software, firmware, etc.), electronic data, databases, other digital information, etc. The memory may include one or more memory units. The one or more memory units may be integrated with one or more other functions (e.g., other functions contained within a device, such as a processor). The memory may include read-only memory (ROM) (e.g., erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), etc.), random access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, and / or other non-transitory computer-readable media for storing information. The memory may be coupled to the processor. The processor may communicate with one or more entities of the memory, for example, via a system bus, directly, etc.

[0157] 16B is a diagram of an example communication system 100 in which one or more disclosed features may be implemented. For example, a wireless network (e.g., a wireless network comprising one or more components of communication system 100) may be configured such that bearers extending beyond the wireless network (e.g., beyond a walled garden associated with the wireless network) can impose QoS characteristics.

[0158] The communications system 100 may be a multiple-access system that provides content, such as voice, data, video, messaging, broadcasts, etc., to multiple wireless users. The communications system 100 may enable multiple wireless users to access such content through sharing of system resources, including wireless bandwidth. For example, the communications system 100 may utilize one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), etc.

[0159] 16B, communications system 100 may include multiple wireless transmit / receive units (WTRUs), e.g., at least one WTRU, such as WTRUs 102a, 102b, 102c, and 102d, a radio access network (RAN) 104, a core network 106, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, although it should be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of WTRUs 102a, 102b, 102c, and 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d may be configured to transmit and / or receive wireless signals and may include user equipment (UE), mobile stations (e.g., WLAN STAs), fixed or mobile subscriber units, pagers, cellular telephones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, consumer electronics, etc.

[0160] The communications system 100 may also include a base station 114a and a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communications networks, such as the core network 106, the Internet 110, and / or the network 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node-B, an eNodeB, a Home Node B, a Home eNodeB, a site controller, an access point (AP), a wireless router, etc. While the base stations 114a, 114b are each shown as a single element, it should be understood that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0161] The base station 114a may be part of the RAN 104, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, etc. The base station 114a and / or base station 114b may be configured to transmit and / or receive wireless signals within a particular geographic area, which may be referred to as a cell (not shown). A cell may be further divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In another embodiment, the base station 114a may utilize multiple-input multiple-output (MIMO) technology and thus utilize multiple transceivers for each sector of the cell.

[0162] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over the air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0163] More specifically, as noted above, the communications system 100 may be a multiple-access system and may utilize one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base station 114a in the RAN 104 and the WTRUs 102a, 102b, 102c may establish the air interface 116 using Wideband CDMA (WCDMA) or may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA). WCDMA may include communications protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High Speed ​​Downlink Packet Access (HSDPA) and / or High Speed ​​Uplink Packet Access (HSUPA).

[0164] In another embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and / or LTE Advanced (LTE-A).

[0165] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 IX, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), or the like.

[0166] The base station 114b of FIG. 16B may be, for example, a wireless router, a Home Node B, a Home eNode B, or an access point and may utilize any suitable RAT for facilitating wireless connectivity within a localized area, such as a business, home, vehicle, campus, etc. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In another embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may establish a picocell or femtocell utilizing a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, etc.). As shown in FIG. 16B, the base station 114b may have a direct connection to the Internet 110. Therefore, the base station 114 b may not need to access the Internet 110 via the core network 106 .

[0167] The RAN 104 may communicate with the core network 106, which may be any type of network configured to provide voice, data, application, and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. For example, the core network 106 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions such as user authentication. Although not shown in FIG. 16B , it should be understood that the RAN 104 and / or core network 106 may communicate directly or indirectly with other RANs that utilize the same RAT as the RAN 104 or a different RAT. For example, in addition to being connected to the RAN 104, which may utilize E-UTRA radio technology, the core network 106 may also communicate with another RAN (not shown) that utilizes GSM radio technology.

[0168] The core network 106 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network providing plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and Internet Protocol (IP) in the TCP / IP Internet protocol suite. The networks 112 may include wired or wireless communication networks owned and / or operated by other service providers. For example, the network 112 may include another core network connected to one or more RANs that may utilize the same RAT as the RAN 104 or a different RAT.

[0169] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities, i.e., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links. For example, the WTRU 102c shown in FIG. 16B may be configured to communicate with a base station 114a, which may utilize cellular-based wireless technology, and a base station 114b, which may utilize IEEE 802 wireless technology.

[0170] FIG. 16C illustrates an exemplary wireless transmit / receive unit, WTRU 102. The WTRU may be a user equipment (UE), a mobile station, a WLAN STA, a fixed or mobile subscriber unit, a pager, a cellular phone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, consumer electronics, etc. The WTRU 102 may be used in one or more of the communication systems described herein. As shown in FIG. 16C, the WTRU 102 may include a processor 118, a transceiver 120, transmit / receive elements 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and other peripherals 138. It should be understood that the WTRU 102 may include any sub-combination of the above elements while remaining consistent with an embodiment.

[0171] The processor 118 may be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. While FIG. 16C depicts the processor 118 and the transceiver 120 as separate components, it should be understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0172] The transmit / receive element 122 may be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) over the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In another embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and receive both RF and light signals. It should be understood that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0173] 16C as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may utilize MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0174] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and demodulate signals received by the transmit / receive element 122. As mentioned above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as UTRA and IEEE 802.11.

[0175] The processor 118 of the WTRU 102 may be coupled to and may receive user input data from a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. Furthermore, the processor 118 may access information from and store data in any type of suitable memory, such as non-removable memory 130 and / or removable memory 132. The non-removable memory 130 may include random access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, etc. In other embodiments, the processor 118 may access information from and store data in memory that is not physically located on the WTRU 102, such as a server or home computer (not shown).

[0176] The processor 118 may receive power from the power source 134 and may be configured to distribute and / or control the power to other components within the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0177] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to or instead of information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) over the air interface 116 and / or may determine its location based on the timing of signals received from two or more neighboring base stations. It should be understood that the WTRU 102 may obtain location information by way of any suitable location determination method while remaining consistent with an embodiment.

[0178] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photos or videos), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth module, a frequency modulation (FM) radio unit, a digital music player, a media player, a video game player module, an internet browser, etc.

[0179] While features and elements may be described above in a particular combination or order, those skilled in the art will understand that each feature or element may be used alone or in any combination with the other features and elements. Furthermore, the methods described herein may be implemented in a computer program, software, or firmware embodied in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media may include electronic signals (transmitted via wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random-access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

1. 1. A station (STA) configured for multi-user multiple-input multiple-output (MU-MIMO) communications, comprising: a processor; a transmitter circuit configured to transmit a MU-MIMO setup frame to a group of responder STAs including at least a first responder STA and a second responder STA, the MU-MIMO setup frame indicating a first antenna for MU-MIMO transmission from the STA to the first responder STA and a second antenna for MU-MIMO transmission from the STA to the second responder STA; the transmitter circuitry configured to transmit a first MU-MIMO transmission to the first responder STA based on an indication of the first antenna and a second MU-MIMO transmission to the second responder STA based on an indication of the second antenna; STA equipped with.

2. 2. The STA of claim 1, wherein the indication of the first antenna includes an indication of a first set of radio frequency (RF) chains and the indication of the second antenna includes an indication of a second set of RF chains.

3. 2. The STA of claim 1, wherein the indication of the first antenna comprises an indication of a first set of virtual antennas and the indication of the second antenna comprises an indication of a second set of virtual antennas.

4. The STA of claim 1 , wherein a first number of spatial streams comprising the first MU-MIMO transmission is different from a second number of spatial streams comprising the second MU-MIMO transmission.

5. The STA of claim 1 , wherein the MU-MIMO setup frame comprises an Enhanced Directional Multi-Gigabit (EDMG) MU-MIMO setup frame.

6. The STA of claim 1 , wherein the MU-MIMO setup frame comprises a medium access control (MAC) frame.

7. The STA of claim 1 , wherein the STA comprises an access point (AP).

8. The STA of claim 1 , further configured to transmit an end frame to a responder STA of the group.

9. 2. The STA of claim 1, further configured to: in response to a MU-MIMO transmission, transmit an end frame to a responder STA of the group, provided that the STA does not receive a response frame from the responder STA of the group.

10. the group includes a third responder STA; The STA of claim 1 , wherein the MU-MIMO setup frame indicates a third antenna for MU-MIMO transmission from the STA to the third responder STA.

11. 1. A method performed in a station (STA) for multi-user multiple-input multiple-output (MU-MIMO) communication, comprising: a transmitter circuit of the STA transmitting a MU-MIMO setup frame to a group of responder STAs including at least a first responder STA and a second responder STA, the MU-MIMO setup frame indicating a first antenna for MU-MIMO transmission from the STA to the first responder STA and a second antenna for MU-MIMO transmission from the STA to the second responder STA; the transmitter circuitry transmitting a first MU-MIMO transmission to the first responder STA based on the indication of the first antenna and a second MU-MIMO transmission to the second responder STA based on the indication of the second antenna; A method for providing the above.

12. 12. The method of claim 11, wherein the indication of the first antenna includes an indication of a first set of radio frequency (RF) chains and the indication of the second antenna includes an indication of a second set of RF chains.

13. 12. The method of claim 11, wherein the indication of the first antenna comprises an indication of a first set of virtual antennas and the indication of the second antenna comprises an indication of a second set of virtual antennas.

14. 12. The method of claim 11, wherein a first number of spatial streams comprising the first MU-MIMO transmission is different from a second number of spatial streams comprising the second MU-MIMO transmission.

15. The method of claim 11 , wherein the MU-MIMO setup frame comprises an enhanced directional multi-gigabit (EDMG) MU-MIMO setup frame.

16. The method of claim 11 , wherein the MU-MIMO setup frame comprises a medium access control (MAC) frame.

17. The method of claim 11 , wherein the STA comprises an access point (AP).

18. The method of claim 11 , further comprising transmitting an end frame to a responder STA of the group.

19. 12. The method of claim 11, further comprising: transmitting an end frame to a responder STA of the group in response to a MU-MIMO transmission, provided that the STA does not receive a response frame from a responder STA of the group.

20. the group includes a third responder STA; The method of claim 11 , wherein the MU-MIMO setup frame indicates a third antenna for MU-MIMO transmission from the STA to the third responder STA.

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