Methods for enhancing WLAN with advanced HARQ design
Methods and apparatus for multi-hybrid automatic repeat request (HARQ) transmission are provided. An access point (AP) may transmit a multi-HARQ transmission to a plurality of stations (STAs). The AP may receive a H-ARQ feedback response from the plurality of STAs. The H-ARQ feedback may include a field to indicate that the H-ARQ feedback is a codeword (CW)/CW group (CWG) based acknowledgment. The H-ARQ feedback may include a packet identification (ID). The packet ID may be a HARQ transmission ID, a sequence number, a MPDU ID or a PPDU ID. The packet ID may be carried in a PLCP header. The H-ARQ feedback may be an aggregated CW/CWG acknowledgment. The H-ARQ feedback may be carried in a null data packet (NDP). A PLCP header of the NDP packet may include a wideband PLCP header and a narrow band PLCP header.
1 . A method implemented by a station (STA), the method comprising:
receiving an indication regarding a multi-access point (AP) Hybrid Automatic Repeat Request (HARQ) transmission for a first AP and a second AP;
receiving a first packet with a first association ID, a first basic service set identifier (BSSID), and a HARQ process ID from the first AP, wherein the first packet is received in a first transmission, wherein the first association ID is carried in a first Physical Layer Conformance Procedure (PLCP) header and indicates that the STA is the intended receiver of the first packet, wherein the first BSSID is a locally unique identifier for the first AP;
comparing the first association ID related to the first packet based on information received from the first AP;
determining, without receiving coordination signaling between the first AP and the second AP, the first packet is a first multi-AP HARQ transmission;
decoding the first packet; and
starting a timer;
receiving a second packet with a second association ID, a second BSSID, and the HARQ process ID from the second AP, wherein the second packet is received in a second transmission, wherein the second association ID is carried in a second PLCP header and indicates that the STA is the intended receiver of the second packet, wherein the second BSSID is a locally unique identifier for the second AP, and wherein the second packet is a second multi-AP HARQ transmission;
comparing the second association ID related to the second packet based on information received from the second AP;
if the timer has not expired, combining the first packet and the second packet to create a combined packet based on the HARQ process ID associated with the first packet matching the HARQ process ID associated with the second packet, and decoding the combined packet, or
if the timer has expired, determining the second packet contains a new transmission, and decoding the second packet; and
broadcasting a response to the first AP and the second AP based on whether the second packet completes the first packet.
2 . The method of claim 1 , further comprising: starting a new timer.
3 . The method of claim 1 , wherein the response is based on whether the second packet is determined to complete the first packet, and whether the timer has expired.
4 . The method of claim 1 , wherein the second packet is received after an extended interframe space (EIFS) period.
5 . The method of claim 1 , wherein the first AP and the second AP are one virtual AP.
6 . The method of claim 1 , wherein the response includes feedback for one or more resource units of the first packet or the second packet.
7 . The method of claim 1 , wherein determining that the first packet is the first multi-AP HARQ transmission comprises determining, based on the first BSSID being different from the second BSSID and the HARQ process ID of the first packet matching the HARQ process ID of the second packet, that the first packet and the second packet correspond to a common retransmission attempt from different access points.
8 . A station (STA) comprising:
a transceiver; and
a processor operatively coupled to the transceiver, wherein the transceiver is configured to:
receive an indication regarding a multi-access point (AP) Hybrid Automatic Repeat Request (HARQ) transmission for a first AP and a second AP; and
receive a first packet with a first association ID, a first basic service set identifier (BSSID), and a HARQ HARQ process ID from the first AP, wherein the first packet is received from a first transmission, wherein the first association ID is carried in a first Physical Layer Conformance Procedure (PLCP) header and indicates that the STA is the intended receiver of the first packet, wherein the first BSSID is a locally unique identifier for the first AP;
the processor is configured to:
compare the first association ID related to the first packet based on information received from the first AP;
determine, without receiving coordination signaling between the first AP and the second AP, the first packet is a first multi-AP HARQ transmission;
decode the first packet; and
start a timer;
the transceiver is configured to receive a second packet with a second association ID, a second BSSID, and the HARQ process ID from the second AP, wherein the second packet is received from a second transmission, wherein the second association ID is carried in a second PLCP header and indicates that the STA is the intended receiver of the second packet, wherein the second BSSID is a locally unique identifier for the second AP, and wherein the second packet is a second multi-AP HARQ transmission;
the processor is configured to:
compare the second association ID related to the second packet based on information received from the second AP;
if the timer has not expired, combine the first packet and the second packet to create a combined packet based on the HARQ process ID associated with the first packet matching the HARQ process ID associated with the second packet, and decode the combined packet, or
if the timer has expired, determine the second packet contains a new transmission, and decode the second packet; and
the transceiver is configured to broadcast a response to the first AP and the second AP based on whether the second packet completes the first packet.
9 . The STA of claim 8 , the processor is further configured to: start a new timer.
10 . The STA of claim 8 , wherein the response is based on whether the second packet is determined to complete the first packet, and whether the timer has expired.
11 . The STA of claim 8 , wherein the second packet is received after an extended interframe space (EIFS) period.
12 . The STA of claim 8 , wherein the first AP and the second AP are one virtual AP.
13 . The STA of claim 8 , wherein the response includes feedback for one or more resource units of the first packet or the second packet.
14 . The STA of claim 8 , wherein processor is configured to determine that the first packet is the first multi-AP HARQ transmission based on the first BSSID being different from the second BSSID and the HARQ process ID of the first packet matching the HARQ process ID of the second packet, and that the first packet and the second packet correspond to a common retransmission attempt from different access points.