Method and apparatus for processing data for transmission in a multi-channel communication system using selective channel inversion

• US 8,040,965 B2
• Filed: 07/09/2009
• Issued: 10/18/2011
• Est. Priority Date: 05/17/2001
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Ling, Fuyun, Walton, Jay Rod, Howard, Steven J., Ketchum, John W., Wallace, Mark S.
• Primary Examiner(s): PUENTE, EVA YI ZHENG
• Application Number:
  US12/499,951
• Publication Number:
  US 20100074351A1
• Time in Patent Office: 831 Days
• Field of Search: 375/260, 375/267, 375/285, 375/227, 375/299, 370/329, 370/480, 370/208, 370/210, 370/204, 455/129
• US Class Current: 375/260
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0068 by puncturing
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04L 2001/0096 Channel splitting in point-to-point links
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0037 Inter-user or inter-terminal allocation
• CPC Class Codes: H04L 5/0046 Determination of how many bits are transmitted on different sub-channels
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04L 5/06 the signals being represented by different frequencies combined with time-division multiplexing H04L5/26
• CPC Class Codes: H04W 52/24 using SIR [Signal to Interference Ratio] or other wireless path parameters
• CPC Class Codes: H04W 52/346 distributing total power among users or channels
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

Techniques to process data for transmission over a set of transmission channels selected from among all available transmission channels. In an aspect, the data processing includes coding data based on a common coding and modulation scheme to provide modulation symbols and pre-weighting the modulation symbols for each selected channel based on the channel'"'"'s characteristics. The pre-weighting may be achieved by “inverting” the selected channels so that the received SNRs are approximately similar for all selected channels. With selective channel inversion, only channels having SNRs at or above a particular threshold are selected, “bad” channels are not used, and the total available transmit power is distributed across only “good” channels. Improved performance is achieved due to the combined benefits of using only the NS best channels and matching the received SNR of each selected channel to the SNR required by the selected coding and modulation scheme.

Claims

1. In a multi-channel communication system comprising components having one or more processors, a method for determining a threshold used to select transmission channels for data transmission, the method comprising:

defining, with a processor, a set of code rates, wherein each code rate is selectable for coding data prior to transmission;

defining, with a processor, a set of setpoints, wherein each setpoint corresponds to a respective code rate and is indicative of a target signal-to-noise-plus-interference ratio (SNR) required at the corresponding code rate for a particular level of performance;

determining, with a processor, a particular number of transmission channels supported by each code rate for achieving the setpoint corresponding to the code rate;

determining, with a processor, a performance criteria for each code rate based in part on the number of supported transmission channels; and

selecting, with a processor, the threshold based on the determined performance criteria for the code rates in the set, and wherein transmission channels are selected for use for data transmission based on the threshold.

2. The method of claim 1, wherein the number of transmission channels supported by each code rate is determined by distributing total available transmit power among the supported transmission channels such that the setpoint corresponding to the code rate is achieved for each supported transmission channel.

3. The method of claim 1, wherein the determined performance criteria for each code rate is an overall throughput computed for the supported transmission channels.

4. An apparatus for determining a threshold used to select transmission channels for data transmission in a multi-channel communication system, the apparatus comprising at least one processor configured to execute logic stored in a memory, the logic comprising:

logic for defining a set of code rates, wherein each code rate is selectable for coding data prior to transmission;

logic for defining a set of setpoints, wherein each setpoint corresponds to a respective code rate and is indicative of a target signal-to-noise-plus-interference ratio (SNR) required at the corresponding code rate for a particular level of performance;

logic for determining a particular number of transmission channels supported by each code rate for achieving the setpoint corresponding to the code rate;

logic for determining a performance criteria for each code rate based in part on the number of supported transmission channels; and

logic for selecting the threshold based on the determined performance criteria for the code rates in the set, and wherein transmission channels are selected for use for data transmission based on the threshold.

5. The apparatus of claim 4, wherein the number of transmission channels supported by each code rate is determined by distributing total available transmit power among the supported transmission channels such that the setpoint corresponding to the code rate is achieved for each supported transmission channel.

6. The apparatus of claim 4, wherein the determined performance criteria for each code rate is an overall throughput computed for the supported transmission channels.

7. An apparatus for determining a threshold used to select transmission channels for data transmission in a multi-channel communication system, comprising:

means for defining a set of code rates, wherein each code rate is selectable for coding data prior to transmission;

means for defining a set of setpoints, wherein each setpoint corresponds to a respective code rate and is indicative of a target signal-to-noise-plus-interference ratio (SNR) required at the corresponding code rate for a particular level of performance;

means for determining a particular number of transmission channels supported by each code rate for achieving the setpoint corresponding to the code rate;

means for determining a performance criteria for each code rate based in part on the number of supported transmission channels; and

means for selecting the threshold based on the determined performance criteria for the code rates in the set, and wherein transmission channels are selected for use for data transmission based on the threshold.

8. The apparatus of claim 7, wherein the number of transmission channels supported by each code rate is determined by distributing total available transmit power among the supported transmission channels such that the setpoint corresponding to the code rate is achieved for each supported transmission channel.

9. The apparatus of claim 7, wherein the determined performance criteria for each code rate is an overall throughput computed for the supported transmission channels.

10. An apparatus having program codes stored thereon, the program codes executable by a processor and causing the processor to:

define a set of code rates, wherein each code rate is selectable for coding data prior to transmission;

define a set of setpoints, wherein each setpoint corresponds to a respective code rate and is indicative of a target signal-to-noise-plus-interference ratio (SNR) required at the corresponding code rate for a particular level of performance;

determine a particular number of transmission channels supported by each code rate for achieving the setpoint corresponding to the code rate;

determine a performance criteria for each code rate based in part on the number of supported transmission channels; and

select the threshold based on the determined performance criteria for the code rates in the set, and wherein transmission channels are selected for use for data transmission based on the threshold.

11. The software apparatus of claim 10, wherein the number of transmission channels supported by each code rate is determined by distributing total available transmit power among the supported transmission channels such that the setpoint corresponding to the code rate is achieved for each supported transmission channel.

12. The software apparatus of claim 10, wherein the determined performance criteria for each code rate is an overall throughput computed for the supported transmission channels.