Wireless communication terminal and wireless communication method for random access-based uplink multi-user transmission
Provided are a wireless communication terminal including: a processor; and a communication unit, wherein the processor obtains a backoff counter for an OFDMA-based random access of the terminal, wherein the backoff counter is obtained within a range of a contention window for the uplink OFDMA-based random access, receives a trigger frame indicating an uplink multi-user transmission, when one or more resource unit(s) in which random access can be performed is indicated by the trigger frame, decrements the backoff counter based on a number of resource units(s) in which random access can be performed, and when the backoff counter is 0 or decremented to 0, performs an uplink multi-user transmission through a selected resource unit among the resource units(s) and a wireless communication method using the same.
1. A wireless communication terminal, the terminal comprising:
a processor; and
a communication unit,
wherein the processor is configured to:
select an orthogonal frequency division multiple access (OFDMA) random access backoff (OBO) counter within a range of a contention window, and
receive a trigger frame including resource allocation information,
select a resource unit among one or more resource units allocated based on the resource allocation information, and
perform carrier sensing on a channel containing the selected resource unit when a specific field included in the trigger frame indicates performing the carrier sensing,
wherein the OBO counter is decremented by a number of the one or more resource units, and
wherein the OBO counter is set to ‘0’ when a value of the OBO counter is smaller than a number of the one or more resource units.
2. The wireless communication terminal of claim 1 , wherein the processor is further configured to:
receive contention window information related to the contention window for performing an uplink OFDMA-based random access (UORA) of the terminal,
wherein the contention window information includes a minimum value of the contention window, and
wherein the contention window is configured based on the minimum value.
3. The wireless communication terminal of claim 1 , wherein an initial value of the contention window is set to the minimum value.
4. The wireless communication terminal of claim 1 , wherein a new OBO counter is determined within the range of the contention window before a next trigger frame is received when the channel including the selected resource unit for uplink multi-user transmission in response to the trigger frame among the one or more resource units is busy according to the carrier sensing and the OBO counter is 0 or decreased to 0.
5. The wireless communication terminal of claim 4 , wherein the processor is further configured to:
participate in a subsequent UORA using the new OBO counter,
wherein the uplink multi-user transmission does not perform through the selected resource unit when the channel is determined to be busy based on the carrier sensing, and
wherein the new OBO counter is randomly determined within the range of the contention window.
6. The wireless communication terminal of claim 5 ,
wherein the contention window for determining the new OBO counter has the same size as an existing contention window.
7. The wireless communication terminal of claim 1 , wherein the uplink multi-user transmission is performed based on the selected resource unit when the channel including the selected resource unit is idle according to the carrier sensing and the OBO counter is 0 or decremented to 0.
8. The wireless communication terminal of claim 1 , wherein the carrier sensing is performed during a SIFS time between the trigger frame and a PHY protocol data unit (PPDU) transmitted in response to the trigger frame.
9. The wireless communication terminal of claim 1 ,
wherein the OBO counter does not decrement when the trigger frame is received but there is no pending data to be transmitted to a base wireless communication terminal, and
wherein a minimum value of the contention window is transmitted through a random access parameter set.
10. A wireless communication method of a wireless communication terminal, the method comprising:
selecting an OFDMA OBO counter within a range of a contention window; and
receiving a trigger frame including resource allocation information;
selecting a resource unit among one or more resource units allocated based on the resource allocation information; and
performing carrier sensing on a channel containing the selected resource unit when a specific field included in the trigger frame indicates performing the carrier sensing,
wherein the OBO counter is decremented by a number of the one or more resource units, and
wherein the OBO counter is set to ‘0’ when a value of the OBO counter is smaller than a number of the one or more resource units.
11. The wireless communication method of claim 10 , the method further comprising:
receiving contention window information related to the contention window for performing an UORA of the terminal,
wherein the contention window information includes a minimum value of the contention window, and
wherein the contention window is configured based on the minimum value.
12. The wireless communication method of claim 11 ,
wherein an initial value of the contention window is set to the minimum value.
13. The wireless communication method of claim 10 , wherein a new OBO counter is determined within the range of the contention window before a next trigger frame is received when the channel including the selected resource unit for uplink multi-user transmission in response to the trigger frame among the one or more resource units is busy according to the carrier sensing and the OBO counter is 0 or decreased to 0.
14. The wireless communication method of claim 13 , the method further comprising:
participating in a subsequent UORA using the new OBO counter,
wherein the uplink multi-user transmission does not performed through the selected resource unit when the channel is determined to be busy based on the carrier sensing, and
wherein the new OBO counter is randomly determined within the range of the contention window.
15. The wireless communication method of claim 14 ,
wherein the contention window for determining the new OBO counter has the same size as an existing contention window.
16. The wireless communication method of claim 10 ,
wherein the uplink multi-user transmission is performed based on the selected resource unit when the channel including the selected resource unit is idle according to the carrier sensing and the OBO counter is 0 or decremented to 0.
17. The wireless communication method of claim 10 ,
wherein the carrier sensing is performed during a SIFS time between the trigger frame and a PHY protocol data unit (PPDU) transmitted in response to the trigger frame.
18. The wireless communication method of claim 10 ,
wherein the OBO counter does not decrement when the trigger frame is received but there is no pending data to be transmitted to a base wireless communication terminal, and
wherein a minimum value of the contention window is transmitted through a random access parameter set.