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EP-4740654-A1 - MULTI-ACCESS POINT COORDINATED BEAMFORMING IN WIRELESS COMMUNICATIONS

EP4740654A1EP 4740654 A1EP4740654 A1EP 4740654A1EP-4740654-A1

Abstract

Various schemes pertaining to multi-access point (multi-AP) coordinated beamforming in wireless communications are described. An apparatus (e. g., a sharing access point (AP) ) triggers a shared AP of a multi-AP system to participate in a coordinated beamforming transmission. The apparatus then transmits a first coordinated beamformed physical-layer protocol data unit (PPDU) which is aligned in time with a second coordinated beamformed PPDU transmitted by the shared AP.

Inventors

  • SEOK, YONGHO
  • LIU, JIANHAN
  • TSAO, WEISUNG
  • ANWYL, GARY A.
  • YEE, JAMES CHIH-SHI

Assignees

  • MediaTek Inc.

Dates

Publication Date
20260513
Application Date
20240703

Claims (20)

  1. A method, comprising: triggering, by a processor of an apparatus implemented in a sharing access point (AP) , a shared AP of a multi-AP system to participate in a coordinated beamforming transmission; and transmitting, by the processor, a first coordinated beamformed physical-layer protocol data unit (PPDU) which is aligned in time with a second coordinated beamformed PPDU transmitted by the shared AP.
  2. The method of Claim 1, wherein the triggering comprises: transmitting a first control frame to the shared AP and one or more stations (STAs) associated with the sharing AP; receiving a respective response frame from each of the shared AP and the one or more STAs; and transmitting a second control frame to the shared AP.
  3. The method of Claim 2, wherein the second control frame indicates that the shared AP is allowed to transmit the second coordinated beamformed PPDU a short interframe space (SIFS) after the second control frame.
  4. The method of Claim 2, wherein the second control frame contains information of the shared AP, a downlink (DL) transmission time and an uplink (UL) transmission time.
  5. The method of Claim 2, wherein the second control frame indicates an uplink (UL) resource unit (RU) allocation time for transmission of a control response by each of one or more stations (STAs) associated with the sharing AP and the shared AP.
  6. The method of Claim 1, wherein the triggering comprises: transmitting a first control frame to the shared AP and one or more stations (STAs) associated with the sharing AP; receiving a respective response frame from each of the shared AP and the one or more STAs; transmitting a second control frame to the shared AP; and receiving a second response frame from the shared AP.
  7. The method of Claim 6, wherein the second control frame contains a respective list of candidate STAs among a set of STAs associated with the shared AP.
  8. The method of Claim 1, wherein the first coordinated beamformed PPDU carries a first data frame for one or more first stations (STAs) associated with the sharing AP, and wherein the second coordinated beamformed PPDU carries a second data frame for one or more second STAs associated with the shared AP.
  9. The method of Claim 1, further comprising: receiving, by the processor, an acknowledgement (ACK) from each of one or more first stations (STAs) associated with the sharing AP, wherein the first coordinated beamformed PPDU is transmitted to the one or more first STAs associated with the sharing AP, and wherein the second coordinated beamformed PPDU is transmitted to one or more second STAs associated with the shared AP.
  10. A method, comprising: receiving, by a processor of an apparatus implemented in a shared access point (AP) , a trigger from a sharing AP of a multi-AP system that triggering the shared AP to participate in a coordinated beamforming transmission; and transmitting, by the processor responsive to receiving the trigger, a second coordinated beamformed physical-layer protocol data unit (PPDU) which is aligned in time with a first coordinated beamformed PPDU transmitted by the sharing AP.
  11. The method of Claim 10, wherein the receiving of the trigger comprises: receiving a first control frame from the sharing AP; transmitting a response frame to the sharing AP responsive to receiving the first control frame; and receiving a second control frame from the sharing AP.
  12. The method of Claim 11, wherein the second control frame indicates that the shared AP is allowed to transmit the second coordinated beamformed PPDU a short interframe space (SIFS) after the second control frame.
  13. The method of Claim 11, wherein the second control frame contains information of the shared AP, a downlink (DL) transmission time and an uplink (UL) transmission time.
  14. The method of Claim 11, wherein the second control frame indicates an uplink (UL) resource unit (RU) allocation time for transmission of a control response by each of one or more stations (STAs) associated with the sharing AP and the shared AP.
  15. The method of Claim 10, wherein the receiving of the trigger comprises: receiving a first control frame from the sharing AP; transmitting a response frame to the sharing AP responsive to receiving the first control frame; and receiving a second control frame from the sharing AP; and transmitting a second response frame to the sharing AP.
  16. The method of Claim 15, wherein the second response frame contains a list of candidate STAs among a set of STAs associated with the shared AP.
  17. An apparatus implementable in a sharing access point (AP) of a multi-AP system, comprising: a transceiver configured to transmit and receive wirelessly; and a processor coupled to the transceiver and configured to perform operations comprising: triggering, via the transceiver, a shared AP of the multi-AP system to participate in a coordinated beamforming transmission; and transmitting, via the transceiver, a first coordinated beamformed physical-layer protocol data unit (PPDU) which is aligned in time with a second coordinated beamformed PPDU transmitted by the shared AP.
  18. The apparatus of Claim 17, wherein the triggering comprises: transmitting a first control frame to the shared AP and one or more stations (STAs) associated with the sharing AP; receiving a respective response frame from each of the shared AP and the one or more STAs; and transmitting a second control frame to the shared AP.
  19. The apparatus of Claim 18, wherein the second control frame indicates that the shared AP is allowed to transmit the second coordinated beamformed PPDU a short interframe space (SIFS) after the second control frame.
  20. The apparatus of Claim 18, wherein the second control frame contains information of the shared AP, a downlink (DL) transmission time and an uplink (UL) transmission time, and wherein the second control frame also indicates an uplink (UL) resource unit (RU) allocation time for transmission of a control response by each of one or more stations (STAs) associated with the sharing AP and the shared AP.

Description

MULTI-ACCESS POINT COORDINATED BEAMFORMING IN WIRELESS COMMUNICATIONS CROSS REFERENCE TO RELATED PATENT APPLICATION The present disclosure is part of a non-provisional patent application claiming the priority benefit of U.S. Provisional Patent Application No. 63/524, 725, filed 03 July 2023, the content of which being incorporated by reference in its entirety. TECHNICAL FIELD The present disclosure is generally related to wireless communications and, more particularly, to multi-access point (multi-AP) coordinated beamforming in wireless communications. BACKGROUND Unless otherwise indicated herein, approaches described in this section are not prior art to the claims listed below and are not admitted as prior art by inclusion in this section. In wireless communications, such as Wi-Fi (or WiFi) and wireless local area networks (WLANs) in accordance with one or more Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (e.g., IEEE 802.11be) , a joint null data packet (NDP) sounding scheme is provided as an optional mode for multi-AP systems. Sequential sounding schemes in which each access point (AP) transmits an NDP independently and sequentially without overlapped sounding period of each AP can also be used in multi-AP systems. The joint NDP sounding scheme for multi-AP systems with less or equal to a total of 8 antennas at each AP has all antennas active on all long-training field (LTF) tones and uses IEEE 802.11ax P matrix across orthogonal frequency-division multiplexing (OFDM) symbols. Multiple APs can sequentially use an IEEE 802.11ax-like sounding sequence to collect channel state information (CSI) from in-basic service set (in-BSS) stations (STAs) and overlapping-basic service set (OBSS) STAs. The sounding sequence of each AP is similar to the IEEE 802.11ax sounding protocol with multiple STAs (e.g., NDP announcement (NDPA) + NDP +beamforming report poll (BFRP) trigger frame (TF) + CSI report) . In sequential channel sounding sequence for multi-APs, the NDPA frame and BFRP TF frame include identity (ID) information for OBSS STA (s) . In a sequential channel sounding sequence for multi-AP systems, IEEE 802.11be supports certain features. For instance, a STA can process the NDPA frame and the BFRP TF received from an OBSS AP, which belongs to a multi-AP set serving the STA. Additionally, if polled by the BFRP TF from the OBSS AP, the STA responds with its corresponding CSI to the OBSS AP. In a scenario in which the IEEE 802.11ax sounding sequence is reused in a multi-AP system, STA11 to STA1N may be associated with AP1, and STA21 to STA2N may be associated with AP2. AP1 may  first transmit NDPA1 followed by NDP1 and a BFRP TF; and in response, each of STA11 to STA1N may a corresponding CSI report to AP1. Then, AP2 may first transmit NDPA2 followed by NDP2 and a BFRP TF; and in response, each of STA21 to STA2N may a corresponding CSI report to AP2. However, for ultra-high reliability (UHR) communications, the above-described scenario tends to be less efficient than desirable, thereby resulting in less-than-ideal system performance. Therefore, there is a need for a solution of multi-AP coordinated beamforming in wireless communications. SUMMARY The following summary is illustrative only and is not intended to be limiting in any way. That is, the following summary is provided to introduce concepts, highlights, benefits and advantages of the novel and non-obvious techniques described herein. Select implementations are further described below in the detailed description. Thus, the following summary is not intended to identify essential features of the claimed subject matter, nor is it intended for use in determining the scope of the claimed subject matter. An objective of the present disclosure is to provide schemes, concepts, designs, techniques, methods and apparatuses pertaining to multi-AP coordinated beamforming in wireless communications. It is believed that implementations of the proposed schemes may address or otherwise alleviate aforementioned issues. For instance, system performance may be improved through implementations of the multi-AP coordinated beamforming under the proposed schemes. In one aspect, a method may involve a sharing AP triggering a shared AP of a multi-AP system to participate in a coordinated beamforming transmission. The method may also involve the sharing AP transmitting a first coordinated beamformed physical-layer protocol data unit (PPDU) which is aligned in time with a second coordinated beamformed PPDU transmitted by the shared AP. In one aspect, a method may involve a shared AP receiving a trigger from a sharing AP of a multi-AP system that triggering the shared AP to participate in a coordinated beamforming transmission. The method may also involve the shared AP, responsive to receiving the trigger, transmitting a second coordinated beamformed PPDU which is aligned in time with a first coordinated beamformed PPDU transmitted by the sharing AP.