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US-20260128775-A1 - METHODS AND APPARATUS FOR PROCESSING CONTROL FRAMES FOR MULTI-AP COLLABORATION

US20260128775A1US 20260128775 A1US20260128775 A1US 20260128775A1US-20260128775-A1

Abstract

Methods and apparatus are disclosed for setting up multi-AP coordinated sounding and beamformed transmission in both single- and multiple-sounding TXOPs. Initial Control trigger frames allocate spatial resources and stations, while Response trigger-based frames confirm participation and exchange multi-AP control information. A MAC-level AID range negotiation method enables APs in overlapping BSSs to prevent duplicate AID assignments. Techniques are further disclosed for sharing sounding control information so that OBSS CSI feedback from STAs can be reliably detected or overheard by participating OBSS APs during coordinated sounding.

Inventors

  • Mahmoud Hasabelnaby
  • Jung Hoon SUH
  • Yan Xin
  • Sara NOROUZI
  • Osama Aboul-Magd

Assignees

  • HUAWEI TECHNOLOGIES CO., LTD.

Dates

Publication Date
20260507
Application Date
20251104

Claims (18)

  1. 1 . A communication method, comprising: transmitting, from a first AP to a second AP, a first Null-Data PPDU Announcement (NDPA) frame comprising first sounding control information; and/or receiving, from the second AP to the first AP, a second NDPA frame comprising second sounding control information, wherein the first NDPA frame or the second NDPA frame comprises a first special station info field and a second special station info field, and the second special station info field carrying one or more of: a recommended channel state information (CSI) ultra-high reliability (UHR) modulation and coding scheme (MCS) level field; a CSI target receive power field; or an AP transmit power field.
  2. 2 . The method of claim 1 , wherein the values of the recommended CSI UHR MCS level field are set according to a worst-case scenario across overlapping basic service set (OBSS) stations.
  3. 3 . The method of claim 1 , wherein the recommended CSI UHR MCS level field is 5 bits and located at bit B 20 -B 24 in the second special station info field.
  4. 4 . The method of claim 1 , wherein value 31 of the recommended CSI UHR MCS level field designating no recommendation.
  5. 5 . The method of claim 1 , further comprising: transmitting, by the first AP a first frame comprising coordinated sounding control information, wherein the coordinated sounding control information comprises the recommended CSI UHR MCS level field; and receiving, by the first AP, a CSI report frame with a MCS level set by the STA according to the coordinated sounding control information in the first frame, wherein the first frame comprises a beamforming report poll (BFRP).
  6. 6 . The method of claim 1 , further comprising: setting the recommended CSI UHR MCS level value to 31 during an initial coordinated beamforming sounding process; and/or updating the recommended CSI UHR MCS level values based on overheard OBSS CSI reports from nearby non-AP stations.
  7. 7 . The method of claim 1 , wherein the first AP is a sharing AP and the second AP is a shared AP, or the first AP is a shared AP and the second AP is a sharing AP.
  8. 8 . A communication method, comprising: receiving, by a station (STA) from access point (AP), a first frame comprising coordinated sounding control information, wherein the coordinated sounding control information comprises a recommended CSI UHR MCS level field; and transmitting, by the station to the AP, a CSI report frame with a MCS level set by the STA according to the coordinated sounding control information in the first frame, wherein the first frame comprises a beamforming report poll (BFRP).
  9. 9 . The method of claim 8 , wherein the AP is a sharing AP or a shared AP.
  10. 10 . An apparatus, comprising: one or more processors couple with a memory storing instructions which, when executed by the one or more processors, cause the apparatus to perform a method, the method comprising: transmitting, from a first AP to a second AP, a first Null-Data PPDU Announcement (NDPA) frame comprising first sounding control information; and/or receiving, from the second AP to the first AP, a second NDPA frame comprising second sounding control information, wherein the first NDPA frame or the second NDPA frame comprises a first special station info field and a second special station info field, and the second special station info field carrying one or more of: a recommended channel state information (CSI) ultra-high reliability (UHR) modulation and coding scheme (MCS) level field; a CSI target receive power field; or an AP transmit power field.
  11. 11 . The apparatus of claim 10 , wherein the values of the recommended CSI UHR MCS level field are set according to a worst-case scenario across overlapping basic service set (OBSS) stations.
  12. 12 . The apparatus of claim 10 , wherein the recommended CSI UHR MCS level field is 5 bits and located at bit B 20 -B 24 in the second special station info field.
  13. 13 . The apparatus of claim 10 , wherein value 31 of the recommended CSI UHR MCS level field designating no recommendation.
  14. 14 . The apparatus of claim 10 , wherein the method further comprising: transmitting, by the first AP a first frame comprising coordinated sounding control information, wherein the coordinated sounding control information comprises the recommended CSI UHR MCS level field; and receiving, by the first AP, a CSI report frame with a MCS level set by the STA according to the coordinated sounding control information in the first frame, wherein the first frame comprises a beamforming report poll (BFRP).
  15. 15 . The apparatus of claim 10 , wherein the method further comprising: setting the recommended CSI UHR MCS level value to 31 during an initial coordinated beamforming sounding process; and/or updating the recommended CSI UHR MCS level values based on overheard OBSS CSI reports from nearby non-AP stations.
  16. 16 . The apparatus of claim 10 , wherein the first AP is a sharing AP and the second AP is a shared AP, or the first AP is a shared AP and the second AP is a sharing AP.
  17. 17 . An apparatus, comprising: one or more processors couple with a memory storing instructions which, when executed by the one or more processors, cause the apparatus to perform a method, the method comprising: receiving, by a station (STA) from access point (AP), a first frame comprising coordinated sounding control information, wherein the coordinated sounding control information comprises a recommended CSI UHR MCS level field; and transmitting, by the station to the AP, a CSI report frame with a MCS level set by the STA according to the coordinated sounding control information in the first frame, wherein the first frame comprises a beamforming report poll (BFRP).
  18. 18 . The apparatus of claim 17 , wherein the AP is a sharing AP or a shared AP.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims the benefit of provisional patent applications U.S. 63/717,589 filed Nov. 7, 2024, titled METHODS AND APPARATUS FOR PROCESSING CONTROL FRAMES FOR MULTI-AP COLLABORATION, U.S. 63/740,753 filed Dec. 31, 2024, titled METHODS AND APPARATUS FOR PROCESSING CONTROL FRAMES FOR MULTI-AP COLLABORATION, U.S. 63/742,275 filed Jan. 6, 2025, titled METHODS AND APPARATUS FOR PROCESSING CONTROL FRAMES FOR MULTI-AP COLLABORATION, and U.S. 63/743,124 filed Jan. 8, 2025, titled METHODS AND APPARATUS FOR PROCESSING CONTROL FRAMES FOR MULTI-AP COLLABORATION, the contents of which are incorporated herein by reference in their entireties. BACKGROUND A Wireless LAN according to IEEE 802.11 specifications has at least one Basic Service Set composed of an access point (AP) and one or more non-access point stations (STAs) associated therewith. Beamforming is the systematic driving of pluralities of antennas belonging to one or more APs or STAs to create constructive interference in a primary direction to boost the signal power reaching a target receiver. Basic service sets can be said to overlap when regions of space lie within a useful communication range of more than one Access Point. In Wireless LAN scenarios with Overlapping Basic Service Sets (OBSSs), coordinated beamforming between Access Points (APs) in overlapping basic service sets (OBSSs) is crucial for improving network efficiency and minimizing interference. By sharing beamforming parameters, APs can enhance signal quality and optimize spatial resource reuse, which is especially important in dense WLAN environments. For coordinated beamforming to function effectively, it requires coordinated sounding between APs, where key parameters for UHR sounding are exchanged. These parameters include bandwidth (BW) for the Null Data Packet (NDP), punctured channel information, the number of Long Training Fields (NLTF) in the NDP, and the configuration of the P-matrix (which defines the size and structure of spatial streams). APs also need to agree on the starting stream index, the number of spatial streams (Nss), and the specific P-matrix rows to use for coordinated transmission. However, incorporating the UHR sounding parameters into the NDPA frame introduces challenges. The existing frame format lacks the space to include essential information for desired coordinated NDP operations. Current 802.11 standards do not provide an established method for coordinating the initial sounding phase to efficiently signal control information across multiple APs. This lack of coordination hinders the effective initiation and management of a shared sounding process, impacting the quality and reliability of subsequent beamforming transmissions. In multi-AP collaboration scenarios, maintaining consistent identification for each Co-BF instance and tracking Co-BF agreements is critical for effective synchronization. However, current protocols lack a standardized method for instance identification and coordination agreement referencing, creating potential conflicts and synchronization issues among APs in a Co-BF group. Coordinated sounding is one of the key features to realize coordinated beamforming (Co-BF) between two OBSSs. In coordinated sounding, a BSS STA may estimate the DL channel which comes from the OBSS AP, and some signaling in Null-Data PPDU Announcement (NDPA) might be required to trigger an OBSS NDP. However, to prevent the OBSS packet decoding burden on the STA side, NDPA and BFRP Trigger frame are transmitted only towards the in-BSS stations. Therefore, an AP needs to ‘overhear’ the required OBSS channel feedback matrix from the OBSS stations. When multiple APs serve overlapping STAs, there is a risk of Address Identifier (AID) conflicts, as each AP may assign AIDs independently. Such conflicts can disrupt communication within the Co-BF environment, reducing efficiency and complicating collaboration. Methods of configuration of coordinated beamforming in a multi-AP collaboration scenario are therefore desired that mitigate one or more deficiencies in the prior art. SUMMARY The present disclosure addresses critical technical challenges that emerge in coordinated beamforming (Co-BF) environments, especially within multi-access point (MAP) collaboration scenarios. In these settings, it is essential to ensure efficient, conflict-free communication between coordinating APs and their associated non-AP STAs to achieve high-performance beamforming transmissions. The present disclosure proposes the use of a Co-BF Initial Control Frame (ICF) and a Co-BF Initial Control Response (ICR) frame to address the lack of coordination in initial sounding and transmission phases. These frames allow APs within a Co-BF coordination group to communicate essential control information for the coordinated sounding process, as well as identify the specific non-AP STAs they intend to serve. This standardized approach significantly improves the