Channel access method and apparatus

• US 10,536,988 B2
• Filed: 11/27/2017
• Issued: 01/14/2020
• Est. Priority Date: 05/27/2015
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Li, Yunbo, Li, Yanchun, Luo, Yi
• Primary Examiner(s): Haile, Awet
• Application Number:
  US15/822,815
• Publication Number:
  US 20180084605A1
• Time in Patent Office: 778 Days
• CPC Class Codes: H04J 2011/0016 with FDM/FDMA and TDM/TDMA
• CPC Class Codes: H04W 74/0858 collision detection
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A channel access process method in a wireless local area network is provided. The method includes: generating, by a station, a backoff counter value; then performing, by the station, a backoff operation after receiving a first trigger frame, where the backoff operation includes: deducting, from the backoff counter value, a quantity N of subchannels for random access, to obtain a new backoff counter value; and when the new backoff counter value is 0 or a negative number, randomly selecting, by the station, one subchannel from the subchannels for random access, and then accessing the subchannel to send an uplink frame. The present application further provides a corresponding channel access apparatus. Applying the method and the apparatus of the embodiments of the present application improves system access efficiency and avoids a waste of system resources.

Claims

1. A channel access method, applied to a wireless local area network, and comprising:

generating, by a station, a backoff counter value, wherein the backoff counter value is randomly selected from a range from zero to CWo, CWo is a contention window for orthogonal frequency division multiple access (OFDMA) subchannel contention, and CWo is an integer greater than 0;

receiving, by the station, a first trigger frame, wherein the first trigger frame is sent by an access point, the first trigger frame indicates a quantity of subchannels for random access, and the quantity of subchannels for random access is an integer greater than or equal to 0;

performing, by the station, backoff operation, wherein the backoff operation comprises;

deducting, from the backoff counter value, the quantity of subchannels for random access, to obtain a new backoff counter value;

when the new backoff counter value is 0 or a negative number,

performing, by the station, channel access, by randomly selecting one subchannel from the subchannels for random access to send an uplink frame;

or when the new backoff counter value is greater than 0, receiving, by the station a second trigger frame sent by the access point, wherein the second trigger frame indicates a quantity of subchannels for random access, and the quantity of subchannels for random access is an integer greater than or equal to 0.

2. The method according to claim 1, wherein the performing the channel access further comprises:

receiving, by the station, a second trigger frame when the station fails in sending the uplink frame, wherein the second trigger frame is sent by the access point, and the second trigger frame comprises a contention window adjustment parameter or a target CWo value; and

adjusting, by the station, CWo after parsing the second trigger frame.

3. The method according to claim 2, wherein the adjusting CWo after parsing the second trigger frame comprises:

comparing the contention window adjustment parameter with a preset threshold; and

when the parameter is greater than the preset threshold, increasing CWo;

or when the parameter is less than or equal to the preset threshold, keeping CWo unchanged.

4. The method according to claim 2, wherein the adjusting CWo after parsing the second trigger frame comprises:

comparing the contention window adjustment parameter with two preset thresholds; and

when the parameter is greater than a first threshold, increasing CWo;

when the parameter is greater than a second threshold and is less than or equal to the first threshold, keeping CWo unchanged;

or when the parameter is less than or equal to the second threshold, decreasing CWo.

5. The method according to claim 2, wherein the adjusting CWo after parsing the second trigger frame comprises:

comparing, by the station, a CWo value before adjustment with the target CWo value; and

when the CWo value is greater than the target CWo value, decreasing CWo;

when the CWo value is equal to the target CWo value, keeping CWo unchanged;

or

when the CWo value is less than the target CWo value, increasing CWo.

6. A channel access apparatus, applied to a wireless local area network, and comprising:

a processor and a transceiver;

wherein

the processor is configured to;

generate a backoff counter value, wherein the backoff counter value is randomly selected from a range from zero to CWo, CWo is a contention window for orthogonal frequency division multiple access (OFDMA) subchannel contention, and CWo is an integer greater than 0;

the transceiver is configured to;

receive a first trigger frame, wherein the first trigger frame is sent by an access point, the first trigger frame indicates a quantity of subchannels for random access, and the quantity of subchannels for random access is an integer grater than or equal to 0;

the processor is further configured to;

perform backoff operation, wherein the backoff operation comprises;

deducting, from the backoff counter value, the quantity of subchannels for random access, to obtain a new backoff counter value; and

perform a determining operation to determine whether the backoff counter value is greater than 0;

the transceiver is further configured to;

receive a second trigger frame when the new backoff counter value is greater than 0, wherein the second trigger frame is sent by the access point, the second trigger frame indicates a quantity of subchannels for random access, and the quantity of subchannels for random access is an integer greater than or equal to 0; and

perform channel access when the new backoff counter value is 0 or a negative number by sending an uplink frame on one randomly selected subchannel of the subchannels for random access.

7. The apparatus according to claim 6, wherein when performing the channel access, the transceiver is further configured to:

receive a second trigger frame when the transceiver fails in sending the uplink frame, wherein the second trigger frame is sent by the access point, and the second trigger frame comprises a contention window adjustment parameter or a target CWo value; and

the processor is configured to adjust CWo after parsing the second trigger frame.

8. The apparatus according to claim 7, wherein when adjusting CWo after parsing the second trigger frame, the processor is further configured to:

compare the contention window adjustment parameter with a preset threshold; and

when the parameter is greater than the preset threshold, increasing CWo;

or when the parameter is less than or equal to the preset threshold, keeping CWo unchanged.

9. The apparatus according to claim 7, wherein when adjusting CWo after parsing the second trigger frame, the processor is further configured to comprises:

compare the contention window adjustment parameter with two preset thresholds; and

when the parameter is greater than a first threshold, increasing CWo;

when the parameter is greater than a second threshold and is less than or equal to the first threshold, keeping CWo unchanged;

or when the parameter is less than or equal to the second threshold, decreasing CWo.

10. The apparatus according to claim 7, wherein when adjusting CWo after parsing the second trigger frame, the processor is further configured to:

compare a CWo value before adjustment with the target CWo value; and

when the CWo value is greater than the target CWo value, decreasing CWo;

when the CWo value is equal to the target CWo value, keeping CWo unchanged;

or

when the CWo value is less than the target CWo value, increasing CWo.

11. A non-transitory computer readable storage medium comprising processor-executable instructions which, when executed by a processor, cause the processor to implement operations including:

generating, a backoff counter value, wherein the backoff counter value is randomly selected from a range from zero to CWo, CWo is a contention window for orthogonal frequency division multiple access (OFDMA) subchannel contention, and CWo is an integer greater than 0;

receiving, a first trigger frame, wherein the first trigger frame is sent by an access point, the first trigger frame indicates that a quantity of subchannels for random access, and the quantity of subchannels for random access is an integer greater than or equal to 0;

performing, backoff operation, wherein the backoff operation comprises;

deducting, from the backoff counter value, the quantity of subchannels for random access, to obtain a new backoff counter value; and

when the new backoff counter value is 0 or a negative number, performing, channel access, by randomly selecting one subchannel from the subchannels for random access to send an uplink frame;

or when the new backoff counter value is greater than 0, receiving a second trigger frame sent by the access point, the second trigger frame indicates a quantity of subchannels for random access, and the quantity of subchannels for random access is an integer greater than or equal to 0.