US-12628091-B2 - Spatial-reuse based TXOP sharing for random access transmissions

Abstract

A wireless station ( 11 ) determines a path loss of a wireless signal path between the wireless station ( 11 ) and a first access point ( 10 ). The first access point ( 10 ) cooperates with a second access point ( 10 ) by sharing a transmit opportunity based on coordinated spatial reuse of at least one resource of the shared transmit opportunity. Further, the wireless station ( 11 ) receives, from the second access point ( 10 ), an indication of a level of allowed interference on the at least one resource of the shared transmit opportunity. Based on the determined path loss and the indication of the level of allowed interference, the wireless station ( 11 ) controls a transmit power of at least one wireless random access transmission performed on the at least one resource of the shared transmit opportunity from the wireless station ( 11 ) to the second access point ( 10 ).

Inventors

• Charlie PETTERSSON
• Jonas SEDIN
• Sebastian MAX

Assignees

• TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

Dates

Publication Date

20260512

Application Date

20220421

Claims (20)

1. 1 . A method of controlling wireless communication in a wireless communication system, performed by a wireless station, the method comprising: determining a path loss of a wireless signal path between the wireless station and a first access point, the first access point cooperating with a second access point by sharing a transmit opportunity (TXOP) based on coordinated spatial reuse of at least one resource of the shared TXOP; receiving, from the second access point, an indication of a level of allowed interference on the at least one resource of the shared TXOP; and controlling, based on the determined path loss and the indication of the level of allowed interference, a transmit power of at least one wireless random access transmission performed on the at least one resource of the shared TXOP from the wireless station to the second access point.
2. 2 . The method of claim 1 , further comprising the receiving, from the second access point, an indication of an identity of the first access point.
3. 3 . The method of claim 1 , further comprising: performing, one or more measurements; and determining the path loss based on the one or more measurements.
4. 4 . The method of claim 3 , further comprising: receiving, from the second access point, an indication of a lower bound of the path loss; and determining the path loss to correspond to the lower bound in response to a failure to determine the path loss based on the one or more measurements.
5. 5 . The method of claim 4 , wherein the lower bound depends on a path loss of a wireless signal path between the first access point and the second access point.
6. 6 . The method of claim 1 , further comprising receiving, from the second access point, an indication of resources of the shared TXOP.
7. 7 . The method of claim 4 , further comprising receiving the indication of the lower bound of the path loss, an indication of resources of the shared TXOP, and/or the indication of an identity of the first access point in a trigger message for triggering one or more wireless transmissions in the shared TXOP.
8. 8 . The method of claim 1 , wherein the level of allowed interference is based on a maximum tolerable level of interference at the first access point.
9. 9 . The method of claim 1 , further comprising selecting randomly the at least one resource from the shared TXOP.
10. 10 . A method of controlling wireless communication in a wireless communication system, performed by an access point, the method comprising: cooperating with a further access point of the wireless communication system by sharing a transmit opportunity (TXOP) based on coordinated spatial reuse of at least one resource of the shared TXOP; receiving, from the further access point, an indication of a first level of allowed interference on the at least one resource of the shared TXOP; sending, to a wireless station, based on the first level of allowed interference, an indication of a second level of allowed interference on the at least one resource of the shared TXOP, to be applied by the wireless station in controlling a wireless random access transmission on the at least one resource of the shared TXOP; and receiving, from the wireless station, at least one wireless random access transmission performed on the at least one resource of the shared TXOP, a transmit power of the at least one wireless random access transmission depending on the indicated second level of allowed interference.
11. 11 . The method of claim 10 , further comprising sending, to the wireless station, an indication of an identity of the further access point.
12. 12 . The method of claim 11 , sending the indication of the second level of allowed interference, an indication of a lower bound of the path loss, an indication of the at least one resource of the shared TXOP, and/or an indication of the identity of the further access point in a trigger message for triggering one or more wireless transmissions in the shared TXOP.
13. 13 . The method of claim 10 , wherein the transmit power is further based on one or more measurements performed by the wireless station to determine a path loss of a wireless signal path between the wireless station and the further access point.
14. 14 . The method of claim 13 , further comprising sending, to the wireless station, an indication of a lower bound of the path loss, wherein the transmit power is further based on the indicated lower bound.
15. 15 . The method of claim 14 , wherein the lower bound depends on a path loss of a wireless signal path between the further access point and the access point.
16. 16 . The method of claim 15 , further comprising performing one or more measurements to determine the path loss of the wireless signal path between the further access point and the access point.
17. 17 . The method of claim 16 , further comprising determining the path loss of the wireless signal path between the further access point and the access point based on one or more measurement reports from the further access point.
18. 18 . The method of claim 10 , further comprising sending, to the wireless station, an indication of resources of the shared TXOP.
19. 19 . A wireless station for controlling wireless communication in a wireless communication system, the wireless station comprising: processing circuitry and memory, the memory containing instructions executable by the processing circuitry, whereby the wireless station is operative to: determine a path loss of a wireless signal path between the wireless station and a first access point, the first access point cooperating with a second access point by sharing a transmit opportunity (TXOP) based on coordinated spatial reuse of at least one resource of the shared TXOP; receive, from the second access point, an indication of a level of allowed interference on the at least one resource of the shared TXOP; and control, based on the determined path loss and the indication of the level of allowed interference, a transmit power of at least one wireless random access transmission performed on the at least one resource of the shared TXOP from the wireless station to the second access point.
20. 20 . An access point for controlling wireless communication in a wireless communication system, the access point comprising: processing circuitry and memory, the memory containing instructions executable by the processing circuitry whereby the access point is operative to: cooperate with a further access point of the wireless communication system by sharing a transmit opportunity (TXOP) based on coordinated spatial reuse of at least one resource of the shared TXOP; receive, from the further access point, an indication of a first level of allowed interference on the at least one resource of the shared TXOP; send, to a wireless station, based on the first level of allowed interference, an indication of a second level of allowed interference on the at least one resource of the shared TXOP, to be applied by the wireless station in controlling a wireless random access transmission on the at least one resource of the shared TXOP; and receive, from the wireless station, at least one wireless random access transmission performed on the at least one resource of the shared TXOP, a transmit power of the at least one wireless random access transmission depending on the indicated second level of allowed interference.

Description

TECHNICAL FIELD The present invention relates to methods for controlling wireless transmissions and to corresponding devices, systems, and computer programs. BACKGROUND In wireless communication technologies, there is an increased interest in using unlicensed bands, like the 2.4 GHz ISM band, the 5 GHz band, the 6 GHz band, and the 60 GHz band using more advanced channel access technologies. Historically, Wi-Fi has been the dominant standard in unlicensed bands when it comes to applications requiring support for high data rates. Due to the large available bandwidth in the unlicensed band, the WLAN (Wireless Local Area Network) technology based on the IEEE 802.11 family standards provides a very simple distributed channel access mechanism based on the so-called distributed coordination function (DCF). Distributed channel access means that a device, in IEEE 802.11 terminology known as a station (STA), tries to access the channel when it has data to send. Effectively there is no difference in channel access whether the station is an access point (AP) or a non-access point (non-AP). DCF works well as long as the load is not too high. When the load is high, and in particular when the number of stations trying to access the channel is large, channel access based on DCF does not work well. The reason for this is that there will be a high probability of collision on the channel, leading to poor channel usage. To improve the channel usage, and in particular to allow for better support of a large number of devices, a more centralized channel access may be utilized. Such centralized channel access may involve that rather than letting a STA access the channel whenever it has data to send, the channel access is controlled by the AP. A corresponding channel access scheme is for example supported in the IEEE 802.11ax technology, see IEEE P802.11ax™/D6.0 Draft Standard for Information technology—Tele-communications and information exchange between systems Local and metropolitan area networks-Specific requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications Amendment 1: Enhancements for High Efficiency WLAN (November 2019), in the following denoted as “IEEE 802.11ax Draft”. The IEEE 802.11ax technology for example supports orthogonal frequency division multiple access (OFDMA) in both downlink (DL), i.e., in a direction from the AP to the STA, and uplink (UL), i.e., in a direction from the STA to the AP. Also multi-user transmission in form of multi-user multiple input multiple output (MU-MIMO) is supported for both the DL and the UL. By supporting MU transmission and letting the AP control the channel access within a cell, efficient channel usage is achieved and one can avoid collisions due to contention in the cell, in the IEEE 802.11 terminology also referred to as basic service set (BSS). A default channel access mechanism used in current WLAN systems is referred to as enhanced distributed channel access (EDCA), as specified in IEEE Standard for Information technology—Telecommunications and information exchange between systems Local and metropolitan area networks—Specific requirements—Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications,” in IEEE Std 802.11-2016 (Revision of IEEE Std 802.11-2012), vol., no., pp. 1-3534, 14 Dec. 2016, in the following denoted as “IEEE 802.11 PHY Specifications”. In the EDCA channel access mechanism, the STA accesses the channel using a set of channel access parameters based on a traffic class of the data. The channel may be obtained for a TXOP (transmit opportunity) which corresponds to a time duration in which multiple frames of the same data class may be transmitted. The maximum size of a TXOP depends on the data priority class. A typical duration of a TXOP is in the range of a few milliseconds. To improve the performance even further, coordination of channel usage between cells may be utilized. Here, one approach is to let a number of APs share a TXOP. For example, if there are two or more APs within range using the same channel, with no coordination each of them would contend for the channel and the AP that wins the contention would then reserve the channel using the TXOP concept. The other APs would have to defer from channel access and wait for the TXOP to end. Then a new contention begins and channel access may or may not be gained for a specific AP. This implies that channel access becomes rather unpredictable and support for demanding QoS (Quality of Service) applications may be challenging. Such issues may be avoided by coordinated sharing of the TXOP by multiple APs. Such features are also referred to as coordinated or cooperating APs (CAP). For example, “Coordinated AP Time/Frequency Sharing in a Transmit Opportunity in 11be”, Internet document IEEE 802.11-19/1582r1 (URL: “https://mentor.ieee.org/802.11/dcn/19/11-19-1582-01-00be-coordinated-ap-time-and-frequency-sharing-in-a-transmit-opportunity