Integrated OFDMA and EDCA channel access mechanism

• US 10,727,922 B2
• Filed: 06/22/2017
• Issued: 07/28/2020
• Est. Priority Date: 06/23/2016
• Status: Active Grant

• Current Assignee: ZTE Corporation
• Original Assignee: ZTE Corporation
• Inventors: Fang, Yonggang
• Primary Examiner(s): Musa, Abdelnabi O
• Application Number:
  US15/630,874
• Publication Number:
  US 20170373736A1
• Time in Patent Office: 1,132 Days
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/066 Combined feedback for a number of channels, e.g. over several subcarriers like in orthogonal frequency division multiplexing [OFDM]
• CPC Class Codes: H04B 7/2612 Arrangements for wireless medium access control, e.g. by allocating physical layer transmission capacity H04B7/2615 - H04B7/2643 take precedence; provision for broadband connection H04Q11/0478
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: H04W 74/002 Transmission of channel access control information
• CPC Class Codes: H04W 74/06 using polling
• CPC Class Codes: H04W 74/0816 with collision avoidance
• CPC Class Codes: H04W 74/085 collision avoidance
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Access to a wireless medium is made more flexible by combining the distributed access and central controlled access. A wireless device may be allowed to perform both orthogonal frequency-division multiple access (OFDMA) and enhanced distributed channel access (EDCA) channel access mechanisms at same time and start the channel access via a mechanism that allows a faster access to the channel. Depending on channel acquisition, the wireless device can use a multi-user format or a single-user format to transmit uplink anPLCP protocol data unit (PPDU).

Claims

1. A method of controlling operation of a wireless network comprising an access point, the method comprising:

transmitting, by the access point, a beacon frame over a wireless transmission medium, wherein the beacon frame comprises a number of contention window parameters for an uplink multiuser random access transmission, and wherein the number of contention window parameters include a minimum contention window value;

resetting, by the access point, a backoff counter value to a random value between zero and the minimum contention window value, wherein the backoff counter is reset in response to the access point determining that an upcoming transmission time is for an orthogonal frequency division multiplexing access (OFDMA) based channel access;

decreasing, by the access point, the backoff counter value by a predetermined value in response to the access point sensing that the wireless transmission medium is idle;

determining, by the access point, whether the backoff counter value is equal to zero;

transmitting, by the access point, a trigger frame for the OFDMA based channel access in response to the access point determining that the backoff counter value is equal to zero;

receiving, in response to the trigger frame, a physical layer convergence protocol (PLCP) protocol data unit (PPDU); and

transmitting an acknowledgement when the PPDU is successfully decoded.

2. The method of claim 1, wherein the receiving of the PLCP protocol data unit (PPDU) comprises:

monitoring, by the access point, an operating channel to receive trigger response frames from a plurality of wireless stations, wherein each trigger response frame includes a preamble and a PLCP protocol data unit (PPDU);

detecting, by the access point, the preamble over the operating channel; and

decoding, after detecting the preamble, the PPDUs over a resource unit (RU).

3. The method of claim 1, further comprising:

maintaining, by the access point, the backoff counter value in responses to sensing that the wireless transmission is not idle; and

monitoring, by the access point, the wireless transmission medium to determine whether the wireless transmission medium is idle.

4. The method of claim 1, wherein the trigger frame comprises an association identifier (AID), the minimum contention window value, the maximum contention window value, an access category (AC), duration, and resource unit (RU).

5. The method of claim 1, wherein the acknowledgement is a multi-user acknowledgement transmitted over a high-efficiency multi-user PPDU on a resource unit.

6. The method of claim 1, wherein the number of contention window parameters includes a single set of contention window parameters shared by both the enhanced distributed channel access (EDCA) based channel access and the orthogonal frequency division multiplexing access (OFDMA) based channel access.

7. The method of claim 1, further comprising:

duplicating, by the access point, the trigger frame for OFDMA based channel access over multiple 20 MHz channels.

8. The method of claim 1, further comprising:

adjusting, by the access point, the contention window parameters in either beacon frame or trigger frame for future OFDMA based channel access, wherein the adjusting of the contention window parameters is in response to the access point not receiving the preamble after a short interframe space (SIFS) time.

9. An access point, comprising:

a processor and a memory having instructions stored thereupon, wherein the instructions upon execution by the processor configures the access point to;

transmit a beacon frame over a wireless transmission medium, wherein the beacon frame comprises a number of contention window parameters for an uplink multiuser random access transmission, and wherein the number of contention window parameters include a minimum contention window value;

reset a backoff counter value to a random value between zero and the minimum contention window value, wherein the backoff counter is reset in response to the access point determining that an upcoming transmission time is for an orthogonal frequency division multiplexing access (OFDMA) based channel access;

decrease the backoff counter value by a predetermined value in response to the access point sensing that the wireless transmission medium is idle;

determine whether the backoff counter value is equal to zero;

transmit a trigger frame for the OFDMA based channel access in response to the access point determining that the backoff counter value is equal to zero;

receive, in response to the trigger frame, a physical layer convergence protocol (PLCP) protocol data unit (PPDU); and

transmit an acknowledgement when the PPDU is successfully decoded.

10. The access point of claim 9, wherein the instructions upon execution by the processor configures the access point to receive the PLCP protocol data unit (PPDU) by:

monitoring an operating channel to receive trigger response frames from a plurality of wireless stations, wherein each trigger response frame includes a preamble and a PLCP protocol data unit (PPDU);

detecting the preamble over the operating channel; and

decoding, after detecting the preamble, the PPDUs over a resource unit (RU).

11. The access point of claim 9, wherein the instructions upon execution by the processor further configures the access point to:

maintain the backoff counter value in responses to sensing that the wireless transmission is not idle; and

monitor the wireless transmission medium to determine whether the wireless transmission medium is idle.

12. The access point of claim 9, wherein the trigger frame comprises an association identifier (AID), the minimum contention window value, the maximum contention window value, an access category (AC), duration, and resource unit (RU).

13. The access point of claim 9, wherein the acknowledgement is a multi-user acknowledgement transmitted over a high-efficiency multi-user PPDU on a resource unit.

14. The access point of claim 9, wherein the number of contention window parameters includes a single set of contention window parameters shared by both the enhanced distributed channel access (EDCA) based channel access and the orthogonal frequency division multiplexing access (OFDMA) based channel access.

15. The access point of claim 9, wherein the instructions upon execution by the processor further configures the access point to:

duplicate the trigger frame for OFDMA based channel access over multiple 20 MHz channels.

16. The access point of claim 9, wherein the instructions upon execution by the processor further configures the access point to:

adjust the contention window parameters in either beacon frame or trigger frame for future OFDMA based channel access, wherein the adjusting of the contention window parameters is in response to the access point not receiving the preamble after a short interframe space (SIFS) time.

17. A method of wireless communication, the method comprising:

receiving, by a wireless station, a contention window parameter, wherein the contention window parameter includes a minimum contention window value, and wherein the contention window parameter is associated with an access category of data;

selecting, by the wireless station, a backoff counter value, wherein the backoff counter is associated with the access category of data, and wherein the backoff counter value is selected to have a value between zero and the minimum contention window value;

decreasing, by the wireless station, the backoff counter value based on a medium sensing and decrementing rule; and

transmitting, when the backoff counter value reaches zero, a random access transmission using a transmission mechanism that is dependent on a random access flag, wherein the transmission mechanism includes

transmitting using a randomly selected resource unit when the random access flag indicates orthogonal frequency division multiplexing access (OFDMA) based channel access, and

transmitting using an entire transmission bandwidth of a channel, when the random access flag indicates an enhanced distribution channel access (EDCA) based channel access.

18. The method of claim 17, further comprising:

resetting, by the wireless station, the backoff counter in response to receiving an acknowledgement from an access point.

19. The method of claim 17, wherein the medium sensing and decrementing rule for decreasing the backoff counter value comprises:

sensing, by the wireless station, the wireless transmission medium;

maintaining, by the wireless station, the backoff counter value in response to determining that the wireless transmission medium is busy;

decoding, by the wireless station, a physical layer convergence protocol (PLCP) protocol data unit (PPDU) in response to determining that the wireless transmission medium is busy;

receiving, by the wireless station, a trigger frame for orthogonal frequency division multiplexing access (OFDMA) based channel access, the trigger frame comprising a number of allocated resource units;

decreasing, by the wireless station, the backoff counter value by the number of allocated resource units; and

setting, by the wireless station, the random access flag to indicate OFDMA based channel access.

20. The method of claim 17, wherein the medium sensing and decrementing rule for decreasing the backoff counter value comprises:

sensing, by the wireless station, the wireless transmission medium;

decreasing, by the wireless station, the backoff counter value by a predetermined value in response to determining that the wireless transmission medium is not busy; and

setting, by the wireless station, the random access flag to indicate EDCA based channel access.

21. The method of claim 17, wherein the access category of data includes any one of a background, a best effort, a video, and a voice.

22. The method of claim 17, further comprising:

setting, by the wireless station, a new contention window parameter to twice that of a previous contention window parameter, wherein the setting of the new contention window is in response to not receiving an acknowledgement from an access point;

resetting the backoff counter after setting the new contention window parameter; and

sensing the wireless transmission medium after resetting the backoff counter.

23. A wireless station, comprising:

a processor and a memory having instructions stored thereupon, wherein the instructions upon execution by the processor configure the wireless station to;

receive a contention window parameter, wherein the contention window parameter includes a minimum contention window value, and wherein the contention window parameter is associated with an access category of data;

select a backoff counter value, wherein the backoff counter is associated with the access category of data, and wherein the backoff counter value is selected to have a value between zero and the minimum contention window value;

decrease the backoff counter value based on a medium sensing and decrementing rule; and

transmit, when the backoff counter value reaches zero, a random access transmission using a transmission mechanism that is dependent on a random access flag, wherein the transmission mechanism includes

transmission using a randomly selected resource unit when the random access flag indicates orthogonal frequency division multiplexing access (OFDMA) based channel access, and

transmission using an entire transmission bandwidth of a channel, when the random access flag indicates an enhanced distribution channel access (EDCA) based channel access.

24. The wireless station of claim 23, wherein the instructions upon execution by the processor further configure the wireless station to:

reset the backoff counter in response to receiving an acknowledgement from an access point.

25. The wireless station of claim 23, wherein the instructions for medium sensing and decrementing rule for decreasing the backoff counter value upon execution by the processor configure the wireless station to:

sense the wireless transmission medium;

maintain the backoff counter value in response to determining that the wireless transmission medium is busy;

decode a physical layer convergence protocol (PLCP) protocol data unit (PPDU) in response to determining that the wireless transmission medium is busy;

receive a trigger frame for orthogonal frequency division multiplexing access (OFDMA) based channel access, the trigger frame comprising a number of allocated resource units;

decrease the backoff counter value by the number of allocated resource units; and

set the random access flag to indicate OFDMA based channel access.

26. The wireless station of claim 23, wherein the instructions for medium sensing and decrementing rule for decreasing the backoff counter value upon execution by the processor configure the wireless station to:

sense the wireless transmission medium;

decrease the backoff counter value by a predetermined value in response to determining that the wireless transmission medium is not busy; and

set the random access flag to indicate EDCA based channel access.

27. The wireless station of claim 23, wherein the access category of data includes any one of a background, a best effort, a video, and a voice.

28. The wireless station of claim 23, wherein the instructions upon execution by the processor further configure the wireless station to:

set a new contention window parameter to twice that of a previous contention window parameter, wherein the setting of the new contention window is in response to not receiving an acknowledgement from an access point;

reset the backoff counter after setting the new contention window parameter; and

sense the wireless transmission medium after resetting the backoff counter.