US 12,137,428 B1
Synchronization of joint transmissions with multiple access points
Rui Cao, Sunnyvale, CA (US); Sudhir Srinivasa, Los Gatos, CA (US); and Honyuan Zhang, Fremont, CA (US)
Assigned to Marvell Asia Pte Ltd, Singapore (SG)
Filed by Marvell Asia Pte Ltd, Singapore (SG)
Filed on May 1, 2023, as Appl. No. 18/141,882.
Application 18/141,882 is a continuation of application No. 17/014,966, filed on Sep. 8, 2020, granted, now 11,641,633.
Claims priority of provisional application 62/897,120, filed on Sep. 6, 2019.
This patent is subject to a terminal disclaimer.
Int. Cl. H04W 56/00 (2009.01); H04L 5/00 (2006.01); H04W 72/044 (2023.01); H04W 84/12 (2009.01)
CPC H04W 56/0045 (2013.01) [H04L 5/0032 (2013.01); H04W 56/001 (2013.01); H04W 72/044 (2013.01); H04W 84/12 (2013.01)] 23 Claims
OG exemplary drawing
 
1. A method for joint wireless communications involving multiple access points (APs), the method comprising:
receiving, at a first AP, a first physical layer (PHY) data unit that is configured to initiate a joint channel sounding procedure between i) a group of APs that includes the first AP and a second AP that transmitted the first PHY data unit, and ii) one or more client stations, the first PHY data unit including in a first PHY preamble of the first PHY data unit a) a first training signal, and b) an indication that the first training signal is to be used by the first AP for determining a relative timing offset between the first AP and the second AP in connection with synchronous data transmissions by the group of APs;
generating, at the first AP, a second PHY data unit for use in the joint channel sounding procedure;
in response to receiving the first PHY data unit, transmitting, by the first AP, the second PHY data unit as part of the joint channel sounding procedure;
receiving, at the first AP, a third PHY data unit that is configured to initiate a first transmission by the first AP that is synchronous with a second transmission by the second AP, the first transmission and the second transmission part of multiple synchronous transmissions to the one or more client stations by the group of APs, wherein the third PHY data unit includes in a second PHY preamble of the third PHY data unit i) a second training signal, and ii) an indication that the first AP is to determine the relative timing offset between the first AP and the second AP using a) the first training signal in the first PHY preamble of the first PHY data unit and b) the second training signal in the second PHY preamble of the third PHY data unit;
calculating, at the first AP, the relative timing offset between the first AP and the second AP using the first training signal using a) the first training signal in the first PHY preamble of the first PHY data unit and b) the second training signal in the second PHY preamble of the third PHY data unit;
generating, at the first AP, a fourth PHY data unit for use in the joint channel sounding procedure; and
in response to receiving the third PHY data unit, transmitting, by the first AP, the fourth PHY data unit as part of the multiple synchronous transmissions to the one or more client stations, including using the relative timing offset to adjust timing of the transmission of the fourth PHY data unit.