Downlink OFDMA for Service Sets with Mixed Client Types

• US 20110222486A1
• Filed: 06/21/2010
• Published: 09/15/2011
• Est. Priority Date: 03/10/2010
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Hart, Brian D.
• Granted Patent: US 8,559,323 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0028 Variable division signaling therefor H04L5/0092
• CPC Class Codes: H04L 5/0037 Inter-user or inter-terminal allocation
• CPC Class Codes: H04L 5/0055 Physical resource allocation for ACK/NACK for physical mapping arrangements in ARQ protocols H04L1/1861
• CPC Class Codes: H04L 5/0064 Rate requirement of the data, e.g. scalable bandwidth, data priority
• CPC Class Codes: H04L 5/0087 when data requirements change
• CPC Class Codes: H04L 5/0094 Indication of how sub-channels of the path are allocated
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers
• CPC Class Codes: H04L 69/323 in the physical layer [OSI layer 1]
• CPC Class Codes: H04W 24/04 Arrangements for maintaining operational condition
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/51 based on terminal or device properties
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

Techniques are provided herein to allow a wireless network access point (AP) to more fully use its bandwidth in order to leverage the different bandwidth capabilities of different types of wireless client devices that the AP serves. The AP generates control parameters for usage of a plurality of channels in a bandwidth during a downlink transmission interval. The control parameters comprise information indicating channel assignments that result in multiple downlink transmissions that at least partially overlap in time to different wireless client devices according to their respective bandwidth capabilities. The AP transmits the control parameters in a control frame in advance of the downlink transmission interval on each of the plurality of channels in the bandwidth.

Claims

1. A method comprising:

at a wireless network access point device, generating control parameters for usage of a plurality of channels in a bandwidth during a downlink transmission interval, the control parameters comprising information indicating channel assignments that result in multiple downlink transmissions that at least partially overlap in time to different wireless client devices according to their respective bandwidth capabilities; and

transmitting in advance of the downlink transmission interval a control frame containing the control parameters on each of the plurality of channels in the bandwidth.

2. The method of claim 1, wherein generating comprises generating control parameters comprising information indicating, during the downlink transmission interval, a downlink transmission will be sent in one channel or several adjacent channels bonded together to at least one wireless client device that has a higher bandwidth capability.

3. The method of claim 2, wherein generating control parameters comprising generating information indicating channel assignment for downlink transmissions in a subset of the plurality of channels to the one or more client devices having the higher bandwidth capability, the subset of the plurality of channels not overlapping with one or more of the plurality of channels used for a downlink transmission to a client device having lower bandwidth capability.

4. The method of claim 3, and further comprising transmitting on the subset of channels from the access point device messages that are configured as acknowledgment messages to cause other devices that detect the acknowledgment messages to refrain from contending for the subset of channels and after a period of time to allow for contention to the subset of channels.

5. The method of claim 3, wherein generating control parameters comprises generating information indicating that acknowledgment messages from the one or more client devices having the higher bandwidth capability are to be sent, in sequence by specific client device, subsequent the acknowledgment message from the client device having the lower bandwidth capability.

6. The method of claim 3, wherein generating control parameters comprises generating information indicating a channel assigned to a corresponding client device identifier for one or more client devices of the higher bandwidth capability during the downlink transmission interval.

7. The method of claim 1, and further comprising, prior to generating the control parameters, contending for the bandwidth to determine availability of the plurality of channels for downlink transmissions, and wherein generating the control parameters is based on which one or more of the plurality of channels in the bandwidth is determined to be available.

8. The method of claim 1, and further comprising generating the control frame comprising a field indicating a time interval beginning from the end of the control frame to completion of an acknowledgment message from the client device having a lower bandwidth capability and at least one field indicating assignment of one or more channels to an identifier for one or more client devices of a higher bandwidth capability that are to receive a downlink transmission during the downlink transmission interval.

9. The method of claim 1, and further comprising determining bandwidth capabilities of the wireless client devices based on information obtained from uplink transmissions received at the access point device from the wireless client devices.

10. The method of claim 1, wherein generating control parameters comprises generating control parameters for a single user multiple-input multiple-output (MIMO) downlink transmission to a wireless client device and for a multi-user MIMO downlink transmission to multiple wireless client devices.

11. The method of claim 1, wherein generating control parameters comprising generating control parameters to scheduling frames for a lower bandwidth capability wireless client device that are longer in duration than for frames for higher bandwidth wireless client devices so that the wireless network access point device transmits or receives at any given time but not transmit and receive at the same time.

12. An apparatus comprising:

at least one transmitter configured to transmit wireless signals in one or more of a plurality of channels in a bandwidth; and

a controller configured to be coupled to the at least one transmitter, wherein the controller is configured to;

generate control parameters for usage of the plurality of channels during a downlink transmission interval, the control parameters comprising information indicating channel assignments that result in multiple downlink transmissions that at least partially overlap in time to different wireless client devices according to their respective bandwidth capabilities; and

supply to the at least one transmitter a control frame containing the control parameters for transmission in advance of the downlink transmission interval on each of the plurality of channels.

13. The apparatus of claim 12, wherein the controller is configured to generate control parameters comprising information indicating, during the downlink transmission interval, a downlink transmission will be sent in one channel or several adjacent channels bonded together to at least one wireless client device that has a higher bandwidth capability.

14. The apparatus of claim 13, wherein the controller is configured to generate the control parameters comprising information indicating channel assignment for downlink transmissions in a subset of the plurality of channels to the one or more client devices having the higher bandwidth capability, the subset of the plurality of channels not overlapping with one or more of the plurality of channels used for a downlink transmission to a client device having lower bandwidth capability.

15. The apparatus of claim 14, wherein the controller is further configured to generate for transmission on the subset of channels messages that are configured as acknowledgment messages to cause other devices that detect the acknowledgment messages to refrain from contending for the subset of channels and after a period of time to allow for contention to the subset of channels.

16. The apparatus of claim 14, wherein the controller is configured to generate parameters comprising information indicating that acknowledgment messages from the one or more client devices having the higher bandwidth capability are to be sent, in sequence by specific client device, subsequent the acknowledgment message from the client device having the lower bandwidth capability.

17. The apparatus of claim 12, wherein the controller is further configured to control the transmitters to adaptively adjust power of downlink transmissions transmitted in different channels according to data rate in order to meet rejection channel capabilities of different client devices.

18. A computer readable medium storing instructions that, when executed by a processor, cause the processor to:

generate control parameters for usage of the plurality of channels during a downlink transmission interval, the control parameters comprising information indicating channel assignments that result multiple downlink transmissions that at least partially overlap in time to different wireless client devices according to their respective bandwidth capabilities; and

supply to at least one transmitter a control frame containing the control parameters for transmission in advance of the downlink transmission interval on each of the plurality of channels.

19. The computer readable medium of claim 18, wherein the instructions that cause the processor to generate the control parameters comprise instructions that cause the processor to generate information indicating, during the downlink transmission interval, a downlink transmission will be sent in one channel or several adjacent channels bonded together to at least one wireless client device that has a higher bandwidth capability.

20. The computer readable medium of claim 19, wherein the instructions that cause the processor to generate the control parameters comprise instructions that cause the processor to generate information indicating channel assignment for downlink transmissions in a subset of the plurality of channels to the one or more client devices having the higher bandwidth capability, the subset of the plurality of channels not overlapping with one or more of the plurality of channels used for a downlink transmission to a client device having lower bandwidth capability.

21. The computer readable medium of claim 20, wherein the instructions that cause the processor to generate the control parameters comprise instructions that cause the processor to generate information indicating that acknowledgment messages from the one or more client devices having the higher bandwidth capability are to be sent, in sequence by specific client device, subsequent the acknowledgment message from the client device having the lower bandwidth capability.

22. The computer readable medium of claim 18, and further comprising instructions that, when executed by the processor, cause the processor to determine bandwidth capabilities of the wireless client devices based on information obtained from uplink transmissions received at the access point device from the wireless client devices.

23. The computer readable medium of claim 18, wherein the instructions that cause the processor to generate the control frame comprise instructions that cause the processor to generate a field indicating a time interval beginning from the end of the control frame to completion of an acknowledgment message from the client device having a lower bandwidth capability and at least one field indicating assignment of one or more channels to an identifier for one or more client devices of a higher bandwidth capability that are to receive a downlink transmission during the downlink transmission interval.