Rate control for multi-channel communications systems

• US 7,167,684 B2
• Filed: 06/23/2005
• Issued: 01/23/2007
• Est. Priority Date: 06/20/2002
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Kadous, Tamer, Fernandez-Corbaton, Ivan Jesus
• Primary Examiner(s): Anderson; Matthew
• Assistant Examiner(s): WEST, LEWIS G
• Application Number:
  US11/165,080
• Publication Number:
  US 20050245197A1
• Time in Patent Office: 579 Days
• Field of Search: 455/67.11, 455/423, 455/450, 455/452.2, 455/452.1, 455/115.1, 455/115.2, 455/115.3, 455/69, 455/522, 370/252, 370/253, 370/208, 375/224, 375/260, 375/346
• US Class Current: 455/67.13
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 1/0045 Arrangements at the receiver end
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/0675 characterised by the signaling
• CPC Class Codes: H04L 1/16 in which the return channel carries supervisory signals, e.g. repetition request signals
• CPC Class Codes: H04L 1/20 using signal quality detector
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 27/2626 Arrangements specific to the transmitter only
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 28/22 Negotiating communication rate
• CPC Class Codes: H04W 52/26 using transmission rate or quality of service QoS [Quality of Service]

Abstract

Techniques and apparatuses to determine a set of rates for a set of data streams to be transmitted in a multi-channel communication system. A group of transmission channels to be used for each data stream is initially identified. An equivalent system for each group is then defined to have an AWGN (or flat) channel and a spectral efficiency equal to the average spectral efficiency of the transmission channels in the group. A metric for each group is then derived based on the associated equivalent system, e.g., set to the SNR needed by the equivalent system to support the average spectral efficiency. A rate for each data stream is then determined based on the metric associated with the data stream. The rate is deemed to be supported by the communication system if the SNR required to support the data rate by the communication system is less than or equal to the metric.

Claims

1. An apparatus for determining rates for a set of data streams to be transmitted over a wireless communication channel in a multi-channel communication system comprising:

a memory; and

a controller coupled with the memory, the controller configured to define an equivalent system for a group of transmission channels based on one or more estimated channel characteristics of the transmission channels and deriving a metric for the transmission channels based on the equivalent system, the controller further configured to determine a particular rate for the data transmission based on the metric.

2. The apparatus of claim 1, wherein the controller is further configured to define the equivalent system to have an additive white Gaussian noise (AWGN) channel and a spectral efficiency equal to an average spectral efficiency of the transmission channels.

3. The apparatus of claim 2, wherein the controller is further configured to determine the average spectral efficiency based on the estimated spectral efficiencies of the transmission channels.

4. The apparatus of claim 3, wherein the controller is further configured estimate the spectral efficiency of each transmission channel based on a constrained spectral efficiency function.

5. The apparatus of claim 4, wherein the controller is further configured to estimate the spectral efficiency of each transmission channel based on a modulation scheme to be used for the data transmission.

6. The apparatus of claim 3, wherein the controller is further configured to estimate the spectral efficiency of each transmission channel based on an unconstrained spectral efficiency function.

7. The apparatus of claim 2, wherein the controller is further configured to determining an equivalent signal-to-noise-and-interference ratio (SNR) for the equivalent system, and wherein the metric is related to the equivalent SNR.

8. The apparatus of claim 1, wherein the controller is further configured to determine a particular modulation scheme to use for the data transmission, and wherein the equivalent system is further defined based on the modulation scheme.

9. The apparatus of claim 1, wherein the controller is further configured to determine an SNR required to support the particular data rate by the communication system, and wherein the particular data rate is determined to be supported by the transmission channels if the SNR required is less than or equal to the metric.

10. The apparatus of claim 1, wherein the one or more estimated channel characteristics comprise an estimated frequency response and an estimated noise variance for the transmission channels.

11. The apparatus of claim 1, wherein the transmission channels are frequency subchannels or spatial subchannels, or both, in a multipath wireless communication channel with frequency selective fading.

12. The apparatus of claim 1, wherein the multi-channel communication system is an orthogonal frequency division multiplex (OFDM) communication system and the transmission channels correspond to frequency subchannels.

13. The apparatus of claim 1, wherein the multi-channel communication system is a multiple-input multiple-output (MEMO) communication system that employs orthogonal frequency division multiplex (OFDM), and the transmission channels correspond to frequency subchannels of spatial subchannels.

14. The apparatus of claim 1, wherein the controller is further configured to determine a different particular rate for each of the group of transmission channels.

15. The apparatus of claim 1, wherein the controller is further configured to determine a same particular rate for at least two of the group of transmission channels.

16. An apparatus for determining rates for a set of data streams to be transmitted over a wireless communication channel in a multi-channel communication system comprising:

a memory; and

a controller coupled with the memory, the controller configured to define an equivalent system for a group of transmission channels based on one or more estimated channel characteristics of the transmission channels and deriving a metric for the transmission channels based on the equivalent system, the controller further configured to determine a rate for each data stream based on the metric associated with the data stream.

17. The apparatus of claim 16, wherein the controller is further configured to define the equivalent system for each transmission channel group to have an additive white Gaussian noise (AWGN) channel and a spectral efficiency equal to an average spectral efficiency of the transmission channels in the group.

18. The apparatus of claim 16, wherein the controller is further configured to estimate the spectral efficiency of each transmission channel based on an unconstrained or constrained spectral efficiency function.

19. The apparatus of claim 16, wherein the controller is further configured to determining an SNR required to support a particular rate by the communication system, for each data stream, and to determine the rate to be supported by the group of transmission channels for the data stream if the required SNP is less than or equal to the metric associated with the data stream.

20. The apparatus of claim 16, wherein the multi-channel communication system is a MIMO communication system that employs OFDM, and the transmission channels correspond to frequency subchannels of spatial subchannels.

21. The apparatus of claim 16, wherein each data stream is transmitted over a respective transmit antenna, and each transmission channel group includes all frequency subchannels for one transmit antenna.

22. An apparatus for determining rates for a set of data streams comprising:

means for defining an equivalent system for a group of transmission channels based on one or more estimated channel characteristics of the transmission channels;

means for deriving at least one metric for the transmission channels based on the equivalent system; and

means for determining a rate for each data stream based on the at least one metric associated with the data steam.

23. The a apparatus of claim 22, wherein the at least one means for defining comprises means for estimating the spectral efficiency of each transmission channel based on an unconstrained or constrained spectral efficiency function.

24. The apparatus of claim 22, wherein the means for determining the rate comprises means for determining an SNR required to support a particular rate by the communication system, for each data stream, and to determine the rate to be supported by the group of transmission channels for the data stream if the required SNR is less than or equal to the metric associated with the data stream.

25. The apparatus of claim 22, wherein the means for determining the rate comprises means for determining so that each data stream is transmitted over a respective transmit antenna, and each transmission channel group includes all frequency subchannels for one transmit antenna.

26. The apparatus of claim 22, further comprising means for determining a particular modulation scheme to use for the data transmission, anti wherein the means for determining an equivalent system comprises means for defining based on the modulation scheme.

27. The apparatus of claim 22, wherein the multi-channel communication system is a multiple-input multiple-output (MIMO) communication and the transmission channels correspond to spatial subchannels.

28. The apparatus of claim 22, wherein the means for determining comprises means for determining a different particular rate for each of the group of transmission channels.

29. The apparatus of claim 22, wherein the means for determining comprises means for determining a same particular rate for at least two of the group of transmission channels.

30. A method of determining rates for a set of data streams comprising:

defining an equivalent system for a group of transmission channels based on one or more estimated channel characteristics of the transmission channels;

deriving at least one metric for the transmission channels based on the equivalent system; and

determining a rate for each data strewn based on the at least one metric associated with the data stream.

31. The method of claim 30, wherein defining comprises estimating the spectral efficiency of each transmission channel based on an unconstrained or constrained spectral efficiency function.

32. The method of claim 30, wherein determining the rate comprises determining an SNR required to support a particular rare by the communication system, for each data stream, and to determine the rate to be supported by the group of transmission channels for the data stream if the required SNR is less than or equal to the metric associated with the data stream.

33. The method of claim 30, wherein determining the rate comprises determining so that each data stream is transmitted over a respective transmit antenna, and each transmission channel group includes all frequency subchannels for one transmit antenna.

34. The method of claim 30, wherein the multi-channel communication system is a multiple-input multiple-output (MIMO) communication and the transmission channels correspond to spatial subchannels.

35. The method of claim 30, wherein determining comprises determining a different particular rate for each of the group of transmission channels.

36. The method of claim 30, wherein determining comprises determining a same particular rate for at least two of the group of transmission channels.

37. A processor readable medium comprising instructions that may be executed by one or more controllers, the instructions comprising:

instructions for defining an equivalent system for a group of transmission channels based on one or more estimated channel characteristics of the transmission channels;

instructions for deriving at least one metric for the transmission channels based on the equivalent system; and

instructions for determining a rate for each data stream based on the at least one metric associated wit the data stream.