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EP-4740673-A1 - DEVICES AND METHODS FOR COORDINATED TRANSMISSION IN A WIRELESS NETWORK

EP4740673A1EP 4740673 A1EP4740673 A1EP 4740673A1EP-4740673-A1

Abstract

An access point, AP, (120) is disclosed configured to gain channel access by participating in a coordinated transmission making use of at least a portion of at least one transmission opportunity, TXOP, obtained and shared by a AP (110), operating as a Sharing AP (110), operating under a coordination agreement and/or within a Multi-AP, M-AP, set (125) of a wireless communication network (100) further including one or more further APs (130, 140) being part of the M-AP set (125) and/or operating under the same coordination agreement. The AP (120) is configured to implement one or more fairness timers, including a first fairness timer and/or a second fairness timer for ensuring a channel access fairness between the AP (120) and the other APs (110, 130, 140) operating under the same coordination agreement within the same M-AP set (125).

Inventors

  • KLEIN, ARIK
  • SHILO, Shimon
  • REDLICH, ODED
  • Tsodik, Genadiy

Assignees

  • Huawei Technologies Co., Ltd.

Dates

Publication Date
20260513
Application Date
20230728

Claims (20)

  1. 1. An access point, AP, (120) configured to gain channel access by participating in a coordinated transmission making use of at least a portion of at least one transmission opportunity, TXOP, (210a-c) obtained and shared by an AP (110), operating as a Sharing AP (110), operating under a coordination agreement and/or within a Multi-AP, M-AP, set (125) of a wireless communication network (100) further including one or more first further APs (130, 140) being part of the M-AP (125) set and/or operating under the same coordination agreement, wherein the AP (120) is configured to implement one or more fairness timers, including a first fairness timer for ensuring a channel access fairness between the AP (120) and one or more second further APs (150, 160, 170) operating on the same channel but not being part of the M-AP set (125) or part of the same coordination agreement or another coordination agreement and/or a second fairness timer for ensuring a channel access fairness between the AP (120) and the first further APs (130, 140) operating under the same coordination agreement and/or being part of the M-AP set (125).
  2. 2. The AP (120) of claim 1, wherein the AP (120) is configured to implement the first fairness timer after being shared for a coordinated transmission by the AP (110), operating as the Sharing AP (110), that has obtained the TXOP (210a-c) for ensuring the channel access fairness between the AP (120) and the one or more second further APs (150, 160, 170) operating on the same channel but not being part of the M-AP set (125) or part of the same coordination agreement or another coordination agreement and wherein the AP (120) is configured to wait for the first fairness timer to end its counting before resuming competing for gaining the channel access.
  3. 3. The AP (120) of claim 2, wherein the AP (120) is configured to wait for the first fairness timer to end before resuming competing for gaining channel access by resuming an Enhanced Distributed Channel Access, EDCA, backoff counter.
  4. 4. The AP (120) of claim 2 or 3, wherein the fairness first timer is defined in units of time.
  5. 5. The AP (120) of any one of the preceding claims, wherein the AP (120) is configured to implement the second fairness timer for ensuring the channel access fairness between the AP (120) and the first further APs (130, 140) operating under the same coordination agreement within the M-AP set (125) that are shared by the AP (110), operating as the Sharing AP (110), and wherein the AP (120) is configured to wait for the second fairness timer to end before participating in another coordinated transmission within the M-AP set (125) or under the same coordination agreement within the M-AP set (125).
  6. 6. The AP (120) of claim 5, wherein the second fairness timer is defined in units of time.
  7. 7. The AP (120) of claim 5 or 6, wherein the second fairness timer is defined in units of TXOPs (210a-c).
  8. 8. The AP (120) of claim 7, wherein the AP (120) is configured to count down the second fairness timer defined in units of TXOPs (210a-c) by decrementing the second fairness timer by one each time the TXOP (210a-c) is held by one or more of the first further APs (130, 140) in the M-AP set (125) or operating under the same coordination agreement within the M-AP set (125).
  9. 9. The AP (120) of claim 8, wherein the AP (120) is configured to start the first fairness timer and/or the second fairness timer at the end of the TXOP (210a-c).
  10. 10. The AP (120) of claim 9, wherein the AP (120) is configured to receive a PPDU from the AP (110), operating as the Sharing AP (110), wherein the PPDU comprises an indication of the duration of the TXOP (210a-c) to start the first fairness timer and/or the second fairness timer.
  11. 11. The AP (120) of any one of claims 1 to 8, wherein the AP (120) is configured to be triggered by the AP (110), operating as the Sharing AP (110), to transmit at least one PPDU as a coordinated transmission and wherein the AP (120) is configured to start the first fairness timer and/or the second fairness timer at the end of the at least one PPDU.
  12. 12. The AP (120) of claim 11, wherein the AP (120) is configured to restart the first fairness timer and/or the second fairness timer, if the AP (120) is triggered by the AP (110), operating as the Sharing AP (110), to transmit at least one further PPDU as a coordinated transmission.
  13. 13. The AP (120) of any one of claims 1 to 8, wherein the AP (120) is configured to receive a frame from the AP (110), operating as the Sharing AP (110), and wherein the frame indicates to the AP (120) to start the first fairness timer and/or the second fairness timer at the end of the frame.
  14. 14. The AP (120) of claim 13, wherein the frame comprises one or more identifiers indicative of the AP (120) and/or one or more of the first further APs (130, 140) in the M-AP set (125) and/or operating under the same coordination agreement within the M-AP set (125) to start the first fairness timer and/or the second fairness timer at the end of the frame.
  15. 15. The AP (120) of any one of the preceding claims, wherein the first fairness timer and/or the second fairness timer are defined by the coordination agreement under which the AP (120) is operating.
  16. 16. The AP (120) of any one of the preceding claims, wherein prior to or at the beginning of the TXOP (210a-c) the AP (120) is configured to receive a frame from the AP (110), operating as the Sharing AP (110), wherein the frame comprises an indication for the AP (120) whether to count for the second fairness timer before participating in another coordinated transmission initiated by any AP (110, 130, 140) operating under the same coordination agreement within the M-AP set (125) or operating in the same M-AP set (125) as the AP (120).
  17. 17. The AP (120) of any one of the preceding claims, wherein the ratio between the values of the first fairness timer and the second fairness timer or the ratio between the values of the second fairness timer and the first fairness timer is defined by a fairness factor.
  18. 18. The AP (120) of claim 17, wherein the fairness factor has a value of 1 or greater or wherein the fairness factor is within the range from 0 to 1 including the boundary values 0 and 1.
  19. 19. The AP (120) of claim 17 or 18, wherein the AP (120) is configured to receive a frame that contains a M-AP EDC A information element from the a AP (110), operating as the Sharing AP (110), within the M-AP set (125), wherein the M-AP EDCA information element comprises one or more parameters, including: the first fairness timer; the second fairness timer; the fairness factor; a minimum size of a M-AP contention window; a maximum size of a M-AP contention window; a M-AP Arbitration Interframe Space Number, AIFSN; and/or a fairness timer initializing point.
  20. 20. The AP (120) of claim 19, wherein the AP (120) is configured to derive the M-AP EDCA information element as an inclusive part of the frame that contains the coordination agreement and transmitted from the AP (110), operating as the Sharing AP (110), wherein the one or more parameters of the M-AP EDCA information element are valid for the duration of the coordination agreement.

Description

DEVICES AND METHODS FOR COORDINATED TRANSMISSION IN A WIRELESS NETWORK TECHNICAL FIELD The present disclosure relates to wireless communications. More specifically, the present disclosure relates to devices and methods for coordinated transmission in a wireless communication network, in particular an IEEE 802.11 -based WLAN. BACKGROUND IEEE 802.11-based WLANs (also referred to as Wi-Fi networks) have become popular at an unprecedented rate. The amendment IEEE 802.1 Ibe introduces a Multi- AP (M-AP) coordinated transmission operation, where multiple access points (APs) share resources to allow coordinated transmissions and utilize their resources more efficiently for communicating with non-AP stations (STA). The main principle of M-AP coordination is that an AP obtaining a transmission opportunity (TXOP) may share its resources with other APs. The group of APs that have decided to cooperate and perform coordinated transmissions can be a subset of a M-AP set. The AP sharing the TXOP is also referred to as the AP operating as the Sharing AP (or short “Sharing AP”), while the other APs participating in the coordinated transmission using the TXOP shared by the Sharing AP are also referred to as APs operating as Shared APs (or short "Shared APs”).. In a Wi-Fi network each AP or non-AP station has to maintain a backoff counter (also referred to as Enhanced Distributed Channel Access, EDCA, backoff counter), by means of which the AP or the non-AP station may determine if it obtains the EDCA TXOP to initiate a frame exchange sequence. A set of EDCA channel access rules defined by the IEEE 802.11 standard define: the conditions in which the backoff counter is set to a value; the conditions in which the backoff counter is decremented; and the conditions in which an EDCA TXOP is obtained. Assuming all EDCA channel access rules are maintained by each of the APs in a Wi-Fi network, the APs that participate in a coordinated transmission gain the access to the channel while their EDCA backoff counters remain unchanged. This may lead to unfairness in the Wi-Fi network for APs that do not support M-AP coordinated transmission, since an AP that is participating in the M-AP coordinated transmission may have an increased access to the channel compared to an AP that is not participating in the M-AP coordinated transmission. SUMMARY It is an objective to provide improved devices and methods for AP coordinated transmission in a wireless communication network, in particular an IEEE 802.11 based WLAN, while keeping the fairness of the access to the channel. The foregoing and other objectives are achieved by the subject matter of the independent claims. Further implementation forms are apparent from the dependent claims, the description and the figures. According to a first aspect an access point, AP, is provided configured to gain channel access by participating in a coordinated transmission making use of at least a portion of at least one transmission opportunity, TXOP, obtained and shared by a Sharing AP, i.e. an AP operating as a Sharing AP, wherein the AP and the Sharing AP operate under a coordination agreement and/or within a Multi- AP, M-AP, set of a wireless, in particular Wi-Fi communication network further including one or more first further APs operating under the same coordination agreement and/or being part of the M-AP set. The AP is configured to implement one or more fairness timers, including a first fairness timer (herein also referred to as M-APInterSetTimer) for ensuring a channel access fairness between the AP and one or more second further APs operating on the same channel but not being part of the M-AP set or part of the same coordination agreement or another coordination agreement and/or a second fairness timer (herein also referred to as M-APIntraSetTimer) for ensuring a channel access fairness between the AP and the first further APs operating under the same coordination agreement and/or being part of the same M-AP set. Thus, an AP is provided for coordinated transmission in a wireless communication network, in particular an IEEE 802.11 based WLAN, allowing to maintain the channel access fairness and, consequently, a reduced collision rate within the wireless communication network. In a further possible implementation form, the AP is configured to implement the first fairness timer after being shared for a coordinated transmission by the AP, operating as the Sharing AP, that has obtained the TXOP for ensuring the channel access fairness between AP and the one or more second further APs operating on the same channel but not being part of the M- AP set or part of the same coordination agreement or another coordination agreement and wherein the AP is configured to wait for the first fairness timer to end, i.e. expire before resuming competing for gaining the channel access. In a further possible implementation form, the AP is configured to wait for the first fairness timer to end, i.e. expire before resumin