Method and apparatus for multi-user direct link transmission
Aspects of the present disclosure generally relate to multi-user (MU) Peer to Peer (P2P) protocols in wireless networks. A first station (STA) may receiving, from an access point (AP), an allocation of a resource unit (RU) for a peer to peer (P2P) communication; transmit, to a peer second STA, a first frame over a first part of the allocated P2P RU; and receive a second frame transmitted by the second STA over a second part of the P2P RU allocated to the first STA by the AP.
1 . A method for wireless communication comprising, at a first station (STA):
receiving, from an access point (AP), an allocation of a resource unit (RU) to the first STA for a peer to peer (P2P) communication;
transmitting, to a peer second STA, a first frame over a first part of the P2P RU; and
receiving a second frame transmitted by the second STA over a second part of the P2P RU allocated to the first STA by the AP,
wherein the first part and the second part are time-multiplexed and separated by a short interframe space (SIFS),
wherein the transmitting of the first frame is configured such that an end of transmission of the second frame by the second STA aligns in time with an end of the P2P RU,
wherein configuring the transmitting of the first frame comprises setting a length of the first frame such that a time remaining for the second part of the P2P RU matches a transmission time of the second frame, and
wherein setting the length of the first frame comprises:
calculating a time TXTIME1 available for the first STA to transmit a physical protocol data unit (PPDU) comprising the first frame based on a time of transmitting the second frame; and
deriving the length of the first frame based on the obtained time TXTIME1 and at least one transmission parameter, such as a modulation and coding scheme (MCS), used for transmitting the first frame,
wherein TXTIME1 is calculated as TXTIME0−TXTIME2−SIFS, where:
TXTIME0 is a duration of the P2P RU allocated by the AP for the P2P communication, and
TXTIME2 is a time required for the second STA to transmit a physical protocol data unit (PPDU) comprising the second frame.
2 . The method of claim 1 , wherein the second frame is a response frame to the first frame.
3 . The method of claim 2 , wherein the second frame is an acknowledgement (ACK) frame sent by the second STA for acknowledging reception of the first frame.
4 . The method of claim 1 , wherein configuring the transmitting of the first frame further comprises including in the first frame a reverse direction (RD) grant addressed to the second STA that allows the second STA to transmit the second frame in reverse direction to the first STA.
5 . The method of claim 4 , wherein configuring the transmitting of the first frame further comprises including in the first frame a duration granted to the second STA to transmit the second frame.
6 . The method of claim 5 , wherein the duration included in the first frame is set to a value equal to TXTIME0−TXTIME1−SIFS.
7 . The method of claim 1 , wherein the allocation of the P2P RU and a length of the P2P RU are included in a trigger frame received from the AP.
8 . The method of claim 1 , wherein the allocation of the P2P RU and a length of the P2P RU are included in a trigger resource scheduling (TRS) field of a data or control frame received from the AP.
9 . The method of claim 7 , wherein the allocation indicates a central frequency of the P2P RU and a frequency bandwidth of the physical protocol data unit (PPDU) comprising the first frame.
10 . The method of claim 9 , wherein TXTIME0 is obtained based on a length or number of data symbols of the P2P RU and at least one transmission parameter, such as a modulation and coding scheme (MCS), specified by the AP.
11 . The method of claim 1 , wherein the second STA is not associated with the AP.
12 . A non-transitory computer-readable medium storing a program which, when executed by a microprocessor or computer system in a device, causes the device to perform the method of claim 1 .
13 . A wireless communication apparatus of a first station (STA), comprising:
a receiver configured to receive, from an access point (AP), an allocation of a resource unit (RU) to the first STA for a peer to peer (P2P) communication; and
a transmitter configured to transmit, to a peer second STA, a first frame over a first part of the P2P RU,
wherein the receiver is further configured to receive a second frame transmitted by the second STA over a second part of the P2P RU allocated to the first STA by the AP,
wherein the first part and the second part are time-multiplexed and separated by a short interframe space (SIFS),
wherein the transmitter is further configured to transmit the first frame such that an end of transmission of the second frame by the second STA aligns in time with an end of the P2P RU,
wherein the transmitter is further configured to set a length of the first frame such that a time remaining for the second part of the P2P RU matches a transmission time of the second frame, and
wherein, to set the length of the first frame, the transmitter is further configured to:
calculate a time TXTIME1 available for the first STA to transmit a physical protocol data unit (PPDU) comprising the first frame based on a time of transmitting the second frame; and
derive the length of the first frame based on the obtained time TXTIME1 and at least one transmission parameter, such as a modulation and coding scheme (MCS), used for transmitting the first frame,
wherein TXTIME1 is calculated as TXTIME0−TXTIME2−SIFS, where:
TXTIME0 is a duration of the P2P RU allocated by the AP for the P2P communication, and
TXTIME2 is a time required for the second STA to transmit a physical protocol data unit (PPDU) comprising the second frame.