Method and system for communication in multi-user multiple-input-multiple-output wireless networks

• US 9,232,543 B2
• Filed: 07/06/2011
• Issued: 01/05/2016
• Est. Priority Date: 07/07/2010
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Zhu, Chunhui
• Primary Examiner(s): MARCELO, MELVIN C
• Application Number:
  US13/177,386
• Publication Number:
  US 20120008490A1
• Time in Patent Office: 1,644 Days
• Field of Search: 370/337, 370/347
• US Class Current: 1/1
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04W 72/56 based on priority criteria
• CPC Class Codes: H04W 72/569 of the traffic information
• CPC Class Codes: H04W 74/0841 with collision treatment

Abstract

Wireless communication in a wireless system using a multiple user transmission opportunity is provided. The data blocks are organized in order of transmission priority based on access categories. Contention for access to the communication medium during a transmission opportunity period is based on a backoff timer of each access category and the transmission priority. Upon successful contention for a transmission opportunity period, during the transmission opportunity period, a data block of a primary access category is wirelessly transmitted from the wireless station to one or more primary destination wireless receivers. Simultaneously, a data block of a secondary access category is wirelessly transmitted from the wireless station to one or more secondary destination wireless receivers. Contending for the transmission opportunity period includes each access category contending for access to the wireless communication medium and a secondary access category selectively invoking communication medium access backoff based on one or more backoff events.

Claims

1. A method of wireless communication in a wireless communication system, comprising:

maintaining data blocks at a wireless transmitting station for transmission to multiple wireless receiving stations over a wireless communication medium, wherein the data blocks are organized based on access categories;

each access category contending for a transmission opportunity period for access to the wireless communication medium; and

upon successful contention, during the transmission opportunity period, transmitting a data block of a primary access category from the transmitting station to a primary destination wireless receiving station, simultaneously transmitting a data block of a secondary access category from the transmitting station to a secondary destination wireless receiving station, over the wireless communication medium;

wherein contending for the transmission opportunity period comprises each access category contending for access to the wireless communication medium, and the secondary access category selectively invoking communication medium access backoff based on a backoff event, wherein invoking communication medium access backoff comprises;

in response to sharing a transmission opportunity period being not possible, the secondary access categories invoking communication medium access backoff.

2. The method of claim 1, wherein invoking communication medium access backoff comprises:

in response to a backoff event, performing direction-based backoff for directional transmissions by identifying a collision spatial area and only invoking backoff for transmissions directed to that spatial area.

3. The method of claim 1, wherein:

invoking communication medium access backoff comprises;

a secondary access category freezing a countdown timer when it begins to share the transmission opportunity period with a primary access category;

after sharing a transmission opportunity period obtained by another access category, the secondary access category resuming countdown of the frozen backoff timer.

4. The method of claim 3, further comprising:

resetting the backoff timer based on the backoff event type before resuming communication channel access and backoff timer countdown, after sharing said transmission opportunity period.

5. The method of claim 3, further comprising:

resuming communication channel access and backoff timer countdown, after sharing said transmission opportunity period.

6. The method of claim 1, wherein communication medium access backoff further comprises:

in response to a successful transmission by a transmission opportunity holder initiated during the transmission opportunity period for an access category, the secondary access category resuming backoff timer countdown.

7. The method of claim 1, wherein communication medium access backoff further comprises:

in response to a successful transmission by a transmission opportunity holder initiated during the transmission opportunity period for an access category, the secondary access category backing off with a contention window reset to a predetermined minimum contention window value, such that a new backoff timer value overwrites a frozen backoff timer value before the transmission opportunity period sharing.

8. The method of claim 1, wherein communication medium access backoff further comprises:

in response to an internal channel access attempt collision at the transmitting station due to a higher priority access category, if the internal collision cannot be resolved by sharing a transmission opportunity period, then invoking exponential backoff, otherwise the secondary access category shares the transmission opportunity period for transmitting data frames and invoke backoff depending on the results of said transmission.

9. The method of claim 1, wherein:

the data blocks are organized into access categories in order of transmission priority;

the transmitting station comprises a multiple-input-multiple-output (MIMO) wireless station, wherein the transmission opportunity comprises a multi-user transmission opportunity (MU-TXOP) for simultaneous transmission of data blocks at different transmission priorities during the MU-TXOP, over the wireless communication medium.

10. The method of claim 1, wherein:

transmitting during the transmission opportunity period comprises directionally transmitting the data blocks of the primary access category from the transmitting station to the primary destination receiving station over the wireless communication medium while simultaneously transmitting the data blocks of the secondary access category from the transmitting station to the secondary destination receiving station over the wireless communication medium.

11. The method of claim 1, wherein:

contending for a transmission opportunity period comprises performing Enhanced Distributed Channel Access (EDCA) to provide Quality of Service (QoS) for a data block in the primary access category; and

transmitting during the transmission opportunity period comprises directionally transmitting the data block of the primary access category from the transmitting station to the primary destination wireless receiving station over the wireless communication medium, and simultaneously transmitting data blocks of secondary access categories from the transmitting station to secondary destination wireless receiving stations over the wireless communication medium.

12. A wireless station for wireless communication in a wireless communication system, comprising:

a communication physical layer configured for wireless communication over a shared wireless communication medium; and

a channel access module configured for maintaining data blocks at a wireless transmitting station for transmission to multiple wireless receiving stations over a wireless communication medium,

wherein the data blocks are organized based on access categories;

wherein upon successful contention by each access category for a transmission opportunity period for access to the wireless communication medium, during the transmission opportunity period the channel access module utilizes the physical layer to transmit a data block of a primary access category to a primary destination wireless receiving station, while simultaneously transmitting a data block of a secondary access category to a secondary wireless receiving station, over the wireless communication medium;

wherein contention for the transmission opportunity period comprises each access category contending for access to the wireless communication medium based, and the secondary access category selectively invoking communication medium access backoff based on backoff event, wherein in response to sharing a transmission opportunity period being not possible, the secondary access category invokes communication medium access backoff.

13. The wireless station of claim 12, wherein

said secondary access category invokes communication medium access backoff in response to a transmission failure event, by performing direction-based backoff for directional transmissions by identifying a collision spatial area and only invoking backoff for transmissions directed to that spatial area.

14. The wireless station of claim 12, wherein:

said secondary access category invokes communication medium access backoff by freezing a countdown timer when it starts to share the transmission opportunity period with a primary access category, and after sharing a transmission opportunity period obtained by another access category, the secondary AC resuming countdown of the frozen backoff timer.

15. The wireless station of claim 14, wherein said secondary access category resets the backoff timer based on the backoff event type before resuming communication channel access and backoff timer countdown, after sharing said transmission opportunity period.

16. The wireless station of claim 14, wherein said secondary access category resumes communication channel access and backoff timer countdown, after sharing said transmission opportunity period.

17. The wireless station of claim 12, wherein in response to a successful transmission by a transmission opportunity holder initiated during the transmission opportunity period for an access category, the secondary access category resumes backoff timer countdown.

18. The wireless station of claim 12, wherein in response to a successful transmission by a transmission opportunity holder initiated during the transmission opportunity period for an access category, the secondary access category backs off with a contention window reset to a predetermined minimum contention window value, such that a new backoff timer value overwrites a frozen backoff timer value before the transmission opportunity period sharing.

19. The wireless station of claim 12, wherein in response to an internal channel access attempt collision at the transmitting station due to a higher priority access category, if the internal collision cannot be resolved by sharing a transmission opportunity period, the access category invokes exponential backoff, otherwise the secondary access category shares the transmission opportunity period for transmitting data frames and invokes backoff depending on the results of said transmission.

20. A wireless communication system, comprising:

a wireless station; and

wireless receivers;

the wireless station comprising;

a communication physical layer configured for wireless communication over a shared wireless communication medium; and

a channel access module configured for maintaining data blocks at a wireless transmitting station for transmission to the wireless receivers over a wireless communication medium,

wherein the data blocks are organized based on access categories;

wherein upon successful contention by each access category for a transmission opportunity period for access to the wireless communication medium, during the transmission opportunity period the channel access module utilizes the physical layer for transmitting a data block of a primary access category to a primary destination wireless receiver, while simultaneously transmitting data blocks of a secondary access category to a secondary wireless receiver over the wireless communication medium;

wherein contention for the transmission opportunity period comprises each access category contending for access to the wireless communication medium based, and the secondary access category selectively invoking communication medium access backoff based on a backoff event, and

wherein in response to sharing a transmission opportunity period being not possible, the secondary access category invokes communication medium access backoff.

21. The system of claim 20, wherein said secondary access category invokes communication medium access backoff in response to a backoff event, by performing direction-based backoff for directional transmissions.

22. The system of claim 21, wherein said secondary access category performs direction based backoff by identifying a collision spatial area and only invoking backoff for transmissions directed to that spatial area.

23. The system of claim 20, wherein:

said secondary access category invokes communication medium access backoff by freezing a countdown timer when it starts to share the transmission opportunity period with a primary access category, and after sharing a transmission opportunity period obtained by another access category, the secondary access category resuming countdown of the frozen backoff timer.

24. The system of claim 23, wherein said secondary access category resets the backoff timer based on the backoff event type before resuming communication channel access and backoff timer countdown, after sharing said transmission opportunity period.

25. The system of claim 23, wherein said secondary access category resumes communication channel access and backoff timer countdown, after sharing said transmission opportunity period.

26. The system of claim 20, wherein a wireless receiver is configured to receive data blocks transmitted from the wireless station over a wireless communication medium, wherein the data blocks are organized based on primary and secondary access categories, and extract from the received data blocks, data blocks of the primary access category and process the data blocks of the primary access category.

27. The system of claim 20, wherein in response to a successful transmission by a transmission opportunity holder initiated during the transmission opportunity period for an access category, the secondary access category resumes backoff timer countdown.

28. The system of claim 20, wherein in response to a successful transmission by a transmission opportunity holder initiated during the transmission opportunity period for an access category, the secondary access category backs off with a contention window reset to a predetermined minimum contention window value, such that a new backoff timer value overwrites a frozen backoff timer value before the transmission opportunity period sharing.

29. The system of claim 20, wherein in response to an internal channel access attempt collision at the transmitting station due to a higher priority access category, if the internal collision cannot be resolved by sharing a transmission opportunity period, the access category invokes exponential backoff, otherwise the secondary access category shares the transmission opportunity period for transmitting data frames and invoke backoff depending on the results of said transmission.