Wireless local area network full-duplex enhancements for scenarios with multiple access-points / BSS

Patent metadata

Field	Value
Publication number	US-12335204-B2
Application number	US-202217814450-A
Country	US
Kind code	B2
Filing date	Jul 22, 2022
Priority date	Aug 20, 2021
Publication date	Jun 17, 2025
Grant date	Jun 17, 2025

Abstract

Full-duplex (FD) enhancements for three scenarios with multiple APs/BSSs. (1) Multiple-AP joint transmissions on a WLAN. Toward eliminating self-interferences and other issues, certain pilot signals in the PPDU are transmitted only by the primary AP. One or more secondary APs participating in the joint transmission receive the pilots to correct their clock in the following symbols. (2) Communications are performed with extended OFDM symbols sent on a second channel which facilitate NAV decoding for stations transmitting on a first channel. (3) More than one AP can perform a joint Ack/BA to a UL PPDU. The secondary AP may utilize its full duplex capability to determine the difference of receiving status between itself and the primary AP, and forward data to the primary which it had not received.

First claim

What is claimed is:

1. An apparatus for wireless communication in a network, the apparatus comprising:
(a) a wireless communication circuit, station, which can be part of an access point (AP) configured for wirelessly communicating with other wireless stations (STAs) over a primary link and a secondary link in performing communication on a wireless local area network (WLAN) under an IEEE 802.11 protocol in which APs on the network operating as a primary AP and secondary APs perform joint transmissions to one or more non-AP stations;
(b) a processor coupled to said wireless communication circuit for operating on the WLAN as a STA;
(c) a non-transitory memory storing instructions executable by the processor; and
(d) wherein said instructions, when executed by the processor, perform one or more steps for overcoming center frequency offset and symbol timing offset caused by residual drift comprising:
(i) transmitting pilot signals within an orthogonal frequency division multiplexing (OFDM) transmission, by an AP operating as a primary AP;
(ii) wherein a portion of the overall set of pilot signals, as primary pilot signals, are only allowed to be transmitted by the primary AP, and not by APs operating as secondary APs;
(iii) wherein each said station operating as a secondary AP is configured with its own clock and upon receiving said pilot signals corrects its clock and the following symbols while performing joint transmission; and
(iv) wherein the primary AP transmits a trigger frame which is received by the secondary APs participating in the joint transmission; wherein said trigger frame establishes the center frequency and/or sampling rate of the joint transmission and synchronizing of the clocks between APs.

2. The apparatus of claim 1 , wherein the secondary AP bases its clock correction on estimated phase difference of primary pilots at different frequency tones, to determine the difference of sampling times between the primary AP and itself, and performs correction on the following symbol(s).

3. The apparatus of claim 1 , wherein the secondary AP bases its clock correction on estimated phase difference of primary pilots at different symbols, to determine a difference in carrier frequency between the primary AP and itself, and performs correction on the following symbol(s).

4. The apparatus of claim 1 , wherein an AP operating as a secondary AP is full duplex capable, while the primary AP is either full duplex or half duplex.

5. The apparatus of claim 1 , wherein a spatial stream to a non-AP STA comprises signals from multiple APs.

6. The apparatus of claim 1 , wherein APs, which are not the primary AP, are configured to send non-primary pilot signals in joint transmission.

7. The apparatus of claim 1 , wherein the station operating as a non-AP station is configured for utilizing received primary pilots to perform phase tracking.

8. The apparatus of claim 1 , wherein said trigger frame contains instructions from the primary AP for precoding the data at the secondary AP for the spatial data stream.

9. The apparatus of claim 1 , wherein the primary and secondary APs precode data and send the spatial data stream and pilots jointly to the non-AP station.

10. An apparatus for wireless communication in a network, the apparatus comprising:
(a) a wireless communication circuit as a station, which can be part of an access point (AP) configured for wirelessly communicating with other wireless stations over a primary link/channel and a secondary link/channel within a single frequency band in performing communication on a wireless local area network (WLAN) under an IEEE 802.11 protocol;
(b) a processor coupled to said wireless communication circuit for operating on the WLAN as a station;
(c) a non-transitory memory storing instructions executable by the processor; and
(d) wherein said instructions, when executed by the processor, perform one or more steps for using neighboring channels in a single radio band for simultaneous transmit and receive (STR) on primary and secondary channels comprising:
(i) transmitting an initial message sent with extended orthogonal frequency division multiplexing (OFDM) symbol(s) on the secondary channel to facilitate operation of a network allocation vector (NAV) decoding for stations transmitting on the primary channel; (ii) performing single band multi-link operations (MLOs) with OFDM symbol alignment between neighboring channels as different links; and
(iii) wherein the primary AP transmits a trigger frame which is received by the secondary APs participating in the joint transmission; wherein said trigger frame establishes the center frequency and/or sampling rate of the joint transmission and synchronizing of the clocks between APs.

11. An apparatus for wireless communication in a network, the apparatus comprising:
(a) a wireless communication circuit, station, which can be part of an access point (AP) configured for wirelessly communicating with other wireless stations over a primary link and a secondary link in performing communication on a wireless local area network (WLAN) under an IEEE 802.11 protocol;
(b) a processor coupled to said wireless communication circuit for operating on the WLAN as a station;
(c) a non-transitory memory storing instructions executable by the processor; and
(d) wherein said instructions, when executed by the processor, perform one or more steps comprising:
(i) allowing more than one AP to transmit a joint acknowledgement (Ack) or block acknowledgement (Ack/BA) to an uplink (UL) PPDU that is intended to a primary AP;
(ii) determining receiver status difference between itself as a secondary AP and that of the primary AP, and said secondary AP forwards the data, which was received by itself but not by the primary AP, to the primary AP instead of requiring a non-AP to perform retransmission to the primary AP; and
(iii) transmitting a trigger frame, by the primary AP, which is received by the secondary APs participating in the joint transmission; wherein said trigger frame establishes the center frequency and/or sampling rate of the joint transmission and synchronizing of the clocks between APs.

Assignees

• Sony Group Corp
• Sony Corp America

Inventors

• Sun Li-Hsiang
• Abouelseoud Mohamed
• Xin Liangxiao
• Xia Qing

Classifications

• H04L5/0048

  Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091) · CPC title

• H04W56/0035 Primary

  detecting errors in frequency or phase · CPC title

• H04W84/12

  WLAN [Wireless Local Area Networks] · CPC title

• H04B7/024

  Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems · CPC title

• H04L5/0051

  of dedicated pilots, i.e. pilots destined for a single user or terminal · CPC title