MULTI-CHANNEL COMMUNICATION STATION FOR COMMUNICATING A MULTI-CHANNEL PPDU AND METHODS OF REDUCING COLLISIONS ON SECONDARY CHANNELS IN MULTI-CHANNEL WIRELESS NETWORKS

• US 20110317674A1
• Filed: 06/29/2010
• Published: 12/29/2011
• Est. Priority Date: 06/29/2010
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Park, Minyoung, Stacey, Robert J.
• Granted Patent: US 8,531,980 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04L 45/24 Multipath
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0044 allocation of payload
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 74/0816 with collision avoidance

Abstract

Embodiments of a very-high throughput communication station and method for communicating on a primary channel and up to three or more secondary channels are generally described herein. Short-preamble detection may be performed during a contention window to detect packet transmissions on any one of the secondary channels starting within the contention window. Guard-interval detection is also performed during the contention window to detect a guard interval of a packet transmission on any one of the secondary channels. The short-preamble detection and the guard-interval detection may be performed concurrently during the contention window to determine if any of the secondary channels are busy.

Claims

1. A communication station configured to communicate on a primary channel and up to three or more secondary channels, the communication station configured to:

perform short-preamble detection during a contention window to detect a packet transmission on any one of the secondary channels starting within the contention window; and

perform guard-interval detection during the contention window to detect a guard interval of a packet transmission on any one of the secondary channels,

wherein the short-preamble detection and the guard-interval detection are performed concurrently during the contention window.

2. The communication station of claim 1 wherein the packet transmission to be detected on one of the secondary channels by either the short-preamble detection or the guard-interval detection comprises packet transmissions of a communication station of a neighboring basic service set having its primary channel co-located on one of the secondary channels.

3. The method of claim 2 wherein the packet transmissions to be detected comprise a protocol data unit having a predetermined structure including a short-training field followed by a long training field followed by OFDM symbols, each OFDM symbol having a guard interval,

wherein the short-preamble detection is to:

identify the short-training field; and

identify likely locations of guard-intervals of the protocol data unit based on the identification of the short-training field and the predetermined structure of the protocol data unit, and

wherein the guard-interval detection comprises performing guard-interval detection at the likely locations of the guard-intervals of the protocol data unit identified by the short-preamble detection.

4. The communication station of claim 1 wherein the guard-interval detection and the short-preamble detection are performed after a distributed coordination function interframe space, and

wherein the distributed coordination function interframe space is provided after an acknowledge packet.

5. The communication station of claim 4 wherein the short-preamble detection comprises detection of a predetermined sequence comprising a short preamble indicating a beginning of a packet transmission, and

wherein the guard-interval detection comprises a correlation to detect a repeating pattern corresponding to a cyclic prefix of an orthogonal frequency division multiplexed (OFDM) symbol within one or more frames of a packet, wherein the detection of a cyclic prefix indicates a valid frame within the packet.

6. The communication station of claim 5 wherein the short-preamble detection is performed to detect packet preambles on any one of the secondary channels starting in time slots of the contention window.

7. The communication station of claim 6 wherein the short-preamble detection is configured to be completed within a time slot of the contention window, and

wherein the guard-interval detection is performed during an interval of a point-coordination function interframe spacing immediately preceding an expiration of a backoff counter.

8. The communication station of claim 1 wherein when either the guard-interval detection or the short-preamble detection detects a packet transmission on one of the secondary channels, the secondary channel is designated as a busy secondary channel, and

wherein when both the guard-interval detection and the short-preamble detection fail to detect a packet transmission on one of the secondary channels, the secondary channel is designated as an idle secondary channel.

9. The communication station of claim 8 wherein the communication station is configured to:

refrain from transmitting on any one of the secondary channels designated as a busy secondary channel; and

when the primary channel is idle, transmit a data unit on the primary channel and any one or more of the secondary channels designated as an idle secondary channel.

10. The communication station of claim 9 wherein to determine if the primary channel is idle or busy, the communication station is further configured to:

perform energy detection in the primary channel during the contention window to determine whether the primary channel is idle or busy;

perform short-preamble detection during the contention window to detect packet transmissions on the primary channel; and

perform guard-interval detection during the contention window to detect a guard interval of a packet transmission on the primary channel.

11. The communication station of claim 9 wherein when the primary channel is determined to be idle for a time that includes a distributed coordination function interframe space plus the contention window, the communication station is configured to transmit a packet on the primary channel and any of the secondary channels that are designated as idle secondary channels.

12. The communication station of claim 11 wherein the communication station is further configured to:

perform a carrier-sense multiple-access with collision-avoidance (CSMA/CA) protocol using a distributed coordination function on the primary channel for access to the primary channel; and

refrain from performing the CSMA/CA protocol on the secondary channels.

13. The communication station of claim 1, wherein the communication station is a very-high throughput (VHT) communication station configured to communicate with an access point over a twenty megahertz primary channel and up to three or more twenty megahertz secondary channels,

wherein the VHT communication station is part of a VHT basic service set (BSS) configured to communicate in accordance with 802.11ac,

wherein the packet transmissions detected on one of the secondary channels by either the short-preamble detection or the guard-interval detection comprise signal transmissions of a communication station of a neighboring BSS, and

wherein the neighboring BSS has its primary channel co-located on one of the secondary channel of the VHT BSS.

14. The communication station of claim 1 further comprising:

a short-preamble detection module to perform the short-preamble detection;

a guard-interval detection module to perform the guard-interval detection;

medium-access control (MAC) layer circuitry; and

logical ‘

OR’

circuitry,

wherein the logical ‘

OR’

circuitry is to provide either a channel busy or channel idle indication to the MAC layer circuitry to designate each of the secondary channels as either busy or idle.

15. A method of communicating a multi-channel data unit on a primary channel and up to three or more secondary channels, the method comprising:

performing short-preamble detection during a contention window to detect a packet transmission on any one of the secondary channels starting within the contention window; and

performing guard-interval detection during the contention window to detect a guard interval of a packet transmission on any one of the secondary channels,

wherein the short-preamble detection and the guard-interval detection are performed concurrently during the contention window.

16. The method of claim 15 wherein the packet transmission to be detected on one of the secondary channels by either performing the short-preamble detection or performing the guard-interval detection comprises packet transmissions of a communication station of a neighboring basic service set having its primary channel co-located on one of the secondary channels.

17. The method of claim 15 wherein the guard-interval detection and the short-preamble detection are performed after a distributed coordination function interframe space, and

wherein the distributed coordination function interframe space is provided after an acknowledge packet.

18. The method of claim 15 wherein when performing either the guard-interval detection or the short-preamble detection detects a packet transmission on one of the secondary channels, the method includes designating the secondary channel as a busy secondary channel, and

wherein when performing both the guard-interval detection and the short-preamble detection fail to detect a packet transmission on one of the secondary channels, the method includes designating the secondary channel as an idle secondary channel.

19. The method of claim 18 further comprising:

refraining from transmitting on any one of the secondary channels designated as a busy secondary channel; and

when the primary channel is idle, transmitting a data unit on the primary channel and any one or more of the secondary channels designated as an idle secondary channel.

20. The method of claim 19 wherein to determine if the primary channel is idle or busy, the method further comprises:

performing energy detection in the primary channel during the contention window to determine whether the primary channel is idle or busy;

performing short-preamble detection during the contention window to detect packet transmissions on the primary channel; and

performing guard-interval detection during the contention window to detect a guard interval of a packet transmission on the primary channel,

wherein when the primary channel is determined to be idle for a time that includes a distributed coordination function interframe space plus the contention window, the method comprises transmitting a packet on the primary channel and any of the secondary channels that are designated as idle secondary channels.

21. A method of transmitting a multi-channel data unit in accordance with IEEE 802.11ac, the method comprising:

performing short-preamble detection during a contention window to detect packet transmissions on any one of a plurality of secondary channels starting within the contention window;

performing guard-interval detection during the contention window to detect a guard interval of a packet transmission on any one of the secondary channels;

designating, based on the short-preamble detection and the guard-interval detection, any of the secondary channels as busy when a packet transmission is detected; and

transmitting a multi-channel data unit on a primary channel and any of the secondary channels that are not designated as busy.

22. The method of claim 21 further comprising:

performing a carrier-sense multiple-access with collision-avoidance (CSMA/CA) protocol using a distributed coordination function (DCF) on the primary channel for access to the primary channel; and

refraining from performing the CSMA/CA protocol on the secondary channels.

23. The method of claim 22 wherein as part of the CSMA/CA protocol, the method further comprises:

performing energy detection in the primary channel during the contention window to determine whether the primary channel is idle or busy;

performing short-preamble detection during the contention window to detect packet transmissions on the primary channel; and

performing guard-interval detection during the contention window to detect a guard interval of a packet transmission on the primary channel.

24. The method of claim 23 wherein the packet transmission to be detected on one of the secondary channels by performing either the short-preamble detection or the guard-interval detection comprises packet transmissions of a communication station of a neighboring basic service set having its primary channel co-located on one of the secondary channels.

25. The method of claim 24 wherein the method is performed by a very-high throughput (VHT) communication station configured to communicate with an access point over a twenty megahertz primary channel and up to three or more twenty megahertz secondary channels,

wherein the VHT communication station is part of a VHT basic service set (BSS) configured to communicate in accordance with 802.11ac,

wherein the packet transmissions to be detected on one of the secondary channels by either the short-preamble detection or the guard-interval detection comprise signal transmissions of a communication station of a neighboring BSS, and

wherein the neighboring BSS has its primary channel co-located on one of the secondary channels of the VHT BSS.

26. A method performed by a station of a basic service set (BSS) configured to operate in accordance with IEEE 802.11 ac for transmitting a multi-channel data unit over a primary channel and up to three or more secondary channels of the BSS, the method comprising detecting transmissions of a station of a neighboring BSS configured to operate in accordance with IEEE 802.11n, wherein a primary channel of the neighboring BSS coincides with one of the secondary channels of the BSS configured in accordance with IEEE 802.11ac,

wherein detecting transmissions of the station of the neighboring BSS comprises performing short-preamble detection during a contention window to detect a packet transmission on the up to three or more secondary channels starting within the contention window.

27. The method of claim 26 further comprising:

performing guard-interval detection during the contention window to detect a guard interval of a packet transmission on any one of the secondary channels; and

designating, based on the short-preamble detection and the guard-interval detection, any of the secondary channels as busy when a packet transmission is detected.

28. The method of claim 27 wherein the packet transmissions to be detected comprise a protocol data unit having a predetermined structure including a short-training field followed by a long training field followed by OFDM symbols, each OFDM symbol having a guard interval,

wherein the short-preamble detection is to:

identify the short-training field; and

identify likely locations of guard-intervals of the protocol data unit based on the identification of the short-training field and the predetermined structure of the protocol data unit, and

wherein the guard-interval detection comprises performing guard-interval detection at the likely locations of the guard-intervals of the protocol data unit identified by the short-preamble detection.

29. The method of claim 27 further comprising:

transmitting a multi-channel data unit on the primary channel of the BSS configured to operate in accordance with IEEE 802.11ac and any of the secondary channels that are not designated as busy; and

refraining from transmitting the multi-channel data unit on any of the secondary channels that are not designated as busy.