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EP-4740670-A1 - CONTROLLING PRIMARY CHANNEL USAGE DURING OPERATIONS ON NONPRIMARY CHANNELS

EP4740670A1EP 4740670 A1EP4740670 A1EP 4740670A1EP-4740670-A1

Abstract

A method implemented in an access point station, AP STA, is disclosed. The AP STA is configured to wirelessly communicate with a first non-access point station, non-AP STA, in a wireless communication system employing listen-before-talk, LBT, and the AP STA operates a first basic service set, BSS, involving a primary channel and a nonprimary channel. the method comprises receiving, from the first non-AP STA on the nonprimary channel, an uplink transmission, based on the first non-AP STA's LBT assessment that the nonprimary channel is idle and the primary channel is busy due to its usage in an overlapping second BSS, and transmitting, on the primary channel, a control frame to control the usage of the primary channel by one or more non-AP STAs of the first BSS. A method for the non-AP STA as well as AP STA and non-AP STA apparatuses are also disclosed.

Inventors

  • AMBEDE, Abhishek
  • WILHELMSSON, LEIF
  • DI TARANTO, ROCCO

Assignees

  • Telefonaktiebolaget LM Ericsson (publ)

Dates

Publication Date
20260513
Application Date
20231109

Claims (20)

  1. 1. A method implemented in an access point station, AP STA, that is configured to wirelessly communicate with a first non-access point station, non-AP STA, in a wireless communication system employing listen-before-talk, LBT, and the AP STA operates a first basic service set, BSS, involving a primary channel and a nonprimary channel, the method comprising: receiving (S144), from the first non-AP STA on the nonprimary channel, an uplink transmission, based on the first non-AP STA’s LBT assessment that the nonprimary channel is idle and the primary channel is busy due to its usage in an overlapping second BSS; transmitting (SI 46), on the primary channel, a control frame to control the usage of the primary channel by one or more non-AP STAs of the first BSS.
  2. 2. The method of claim 1, wherein the control frame transmitted on the primary channel by the AP STA is arranged to cause one out of the following controlled usage actions: a. non-AP STAs of the first BSS omit transmitting on the primary channel, b. at least one second non-AP STA transmits an uplink transmission to the AP STA on the primary channel, c. at least one second non-AP STA transmits a peer-to-peer transmission to at least one third non-AP STA on the primary channel.
  3. 3. The method of claim 2, wherein a duration of the caused controlled usage action on the primary channel is arranged not to exceed a duration indicated in the control frame transmitted by the AP STA, and where the duration indicated in the control frame corresponds to an expected duration of a communication on the nonprimary channel between the AP STA and the first non-AP STA.
  4. 4. The method of claim 2 or 3, wherein the uplink transmission or the peer-to-peer transmission on the primary channel is time-aligned with transmissions on the nonprimary channel.
  5. 5. The method of any of the previous claims, where the uplink transmission received from the first non-AP STA on the nonprimary channel is a control frame sent by the first non-AP STA prior to sending an uplink data transmission.
  6. 6. The method of claim 5, where the control frame sent by the first non-AP STA on the nonprimary channel is a request-to-send, RTS, frame.
  7. 7. The method of claim 5, where the control frame sent by the first non-AP STA on the nonprimary channel is a clear-to-send-to-self, CTS-to-self, control frame.
  8. 8. The method of any of the previous claims, further comprising transmitting a scheduling of single-user or multi-user downlink or uplink communications involving the first non-AP STA, wherein the scheduling does not allocate frequency resources of the primary channel to the first non-AP STA.
  9. 9. The method of any of the previous claims, wherein the wireless communication system is based on a Wireless Local Area Network technology according to the IEEE 802.11 standards family.
  10. 10. The method of claim 9, wherein the primary channel is a primary 20 MHz channel, or a primary 40 MHz channel, or a primary 80 MHz channel, or a primary 160 MHz channel.
  11. 11. The method of any of claims 5 to 10 when depending on at least claim 2 where the non-AP STAs of the first BSS are caused to omit transmitting on the primary channel, where the control frame transmitted on the primary channel by the AP STA is a clear- to-send, CTS, frame or a CTS-to-self frame.
  12. 12. The method of any of claims 5 to 10 when depending on at least claim 2 where at least one second non-AP STA transmits an uplink transmission to the AP STA on the primary channel or at least one second non-AP STA transmits a peer-to-peer transmission to at least one third non-AP STA on the primary channel, where the control frame transmitted on the primary channel by the AP STA is a trigger frame.
  13. 13. A method implemented in a non-access point station, non-AP STA, that is configured to wirelessly communicate with an access point station, AP STA, in a wireless communication system employing listen-before-talk, LBT, where the AP STA operates a first basic service set, BSS, involving a primary channel and a nonprimary channel, the method comprising assessing the primary and nonprimary channels, wherein the non-AP STA assesses that the nonprimary channel is idle and the primary channel is busy due to its usage in an overlapping second BSS, performing: notifying (S148), on the nonprimary channel, the AP STA about inability to communicate using the primary channel; and receiving a scheduling of communications involving the non-AP STA, wherein the scheduling does not allocate frequency resources of the primary channel to the first STA .
  14. 14. The method of claim 13, wherein the notifying (S148) of the AP STA on the nonprimary channel comprises transmitting a control frame.
  15. 15. The method of any one of claims 13 to 14, wherein the notifying (S148) of the AP STA is performed using one out of a. a single bit to indicate the idle/busy status of the primary channel; and b. a bitmap to indicate idle/busy status of multiple subchannels, the multiple subchannels at least including the primary channel.
  16. 16. The method of any one of claims 13 to 15, further comprising notifying the AP STA on the nonprimary channel about a duration of inability to communicate using the primary channel, where the notified duration corresponds to the identified duration of the overlapping second BSS’s communications on the primary channel.
  17. 17. The method of any one of claims 13 to 16, further comprising notifying the AP STA on the nonprimary channel about a duration of inability to communicate using the primary channel when the identified duration of the overlapping second BSS’s communications on the primary channel is larger than a threshold.
  18. 18. The method of claim 17, further comprising that the threshold is determined: a. by the AP STA; or b. by the non-AP STA; or c. by means of negotiation between the AP STA and the non-AP STA.
  19. 19. The method of any one of claims 13 to 18, wherein the wireless communication system is based on a Wireless Local Area Network technology according to the IEEE 802.11 standards family.
  20. 20. The method of claim 19, wherein the primary channel is a primary 20 MHz channel, or a primary 40 MHz channel, or a primary 80 MHz channel, or a primary 160 MHz channel.

Description

CONTROLLING PRIMARY CHANNEL USAGE DURING OPERATIONS ON NONPRIMARY CHANNELS TECHNICAL FIELD The present disclosure relates to wireless communications, and in particular, to controlling primary channel usage. BACKGROUND Wi-Fi, also known as Wireless Local Area Network (WLAN), is a technology that currently mainly operates in the 2.4 GHz, the 5 GHz band, and the 6 GHz frequency bands. There are specifications regulating an access point’s or wireless terminals' physical (PHY) layer, medium access layer (MAC) layer and other aspects in order to secure compatibility and inter-operability between different WLAN entities, e.g., between an access point and mobile terminals, both of which may be referred to as stations (STAs) herein. Wi-Fi is generally operated in license-exempt bands, and as such, communication over Wi-Fi may be subject to interference sources from any number of known and unknown devices. Wi-Fi is commonly used as wireless extensions to fixed broadband access, e.g., in domestic environments and hotspots, like airports, train stations and restaurants. If a wireless system is operating in license-exempt bands, like is the case for Institute of Electrical and Electronics Engineers (IEEE) 802.11 WLANs, it typically uses the listen before talk (LBT) mechanism, also referred to as carrier sense multiple access with collision avoidance (CSMA/CA), to gain access to the channel. The working procedure of LBT may operate as follows. Before a transmission can be initiated, a transmitter listens on the wireless medium to determine whether a desired channel is occupied (“busy”) or unoccupied (“idle”) by using an appropriate carrier sensing mechanism. If the channel is found to be “idle,” the transmission can be initiated with a channel access mechanism that involves a random backoff procedure. On the contrary, if the channel is found to be “busy,” the transmitter must defer from transmission and essentially keep sensing the channel until it becomes idle. The communication is challenging, especially in the presence of interference which may occur, for example, due to collisions when other transmitters (e.g., hidden nodes) gain access to the channel at the same time or when there are other systems (wideband or narrowband) operating in partially or completely overlapping channels. Primary and nonprimary channels in IEEE 802.11 WLANs A basic service set (BSS) in IEEE 802.11 (WLANs) typically comprises an AP STA which possibly serves one or more non-AP STAs associated with it. Every BSS has a primary channel, which is the common channel of operation for all STAs that are members of the BSS. For example, in a 20 MHz, 40 MHz, 80 MHz, 160 MHz or 320 MHz BSS the primary channel is a primary 20 MHz channel. Some frames such as beacon frames are always sent only on the primary 20 MHz channel. In addition to a primary 20 MHz, a BSS whose operating bandwidth is larger than 20 MHz can also have a primary 40 MHz channel, a primary 80 MHz channel, etc. All primary channels of bandwidth wider than 20 MHz necessarily include at least the primary 20 MHz channel. Corresponding to the primary channel nomenclature, all channels other than a primary channel are termed corresponding nonprimary channels. Channel Bonding in IEEE 802.11 WLANs Channel bonding, introduced in the IEEE 802.1 In High Throughput (HT) amendment, allows an IEEE 802.11 STA to cascade adjacent primary/nonprimary channels to increase the transmission bandwidth. FIG. l is a diagram of an example illustrating channel bonding nomenclature and some related channel hierarchy. When a transmitter performs carrier sensing for attempting a transmission over the wireless medium, the allowed transmission bandwidth is determined by first assessing whether the primary 20 MHz channel of the operating bandwidth is ‘idle’ and then assessing and appropriately cascading the nonprimary channels. For example, an 80 MHz transmission is composed of one primary 40 MHz channel and one secondary (i.e., nonprimary) 40 MHz channel. Furthermore, the primary 40 MHz channel is itself composed of one primary 20 MHz channel and one secondary (i.e., nonprimary) 20 MHz channel. Even if channel bonding is aimed at improving the flexibility of transmissions, it still comes with significant limitations. As an example based on FIG. 1 and how a transmitter and receiver can interact to determine an allowed transmission bandwidth, if P2 happens to be not available at the receiver (while the whole 160 MHz is available at the transmitter), then only Pl can be used and this means that only 20 MHz in a 160 MHz channel may be used regardless of the status of P3 up to P8. Nonprimary channel usage in UHR SG In IEEE 802.11 Ultra High Reliability (UHR) Study Group (SG), that is the initial SG phase of a planned IEEE 802.11 task group bn (TGbn) that will define and standardize the features of the future Wi-Fi 8 by means of the IEEE 802.1 Ibn amendment, there are ongoing discussions to define features that may all