Rate control adaptable communications

• US 8,898,547 B2
• Filed: 05/09/2009
• Issued: 11/25/2014
• Est. Priority Date: 05/31/2002
• Status: Expired due to Fees

• Current Assignee: Broadcom Corporation (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Cameron, Kelly Brian, Shen, Ba-Zhong, Tran, Hau Thien
• Primary Examiner(s): Torres, Joseph D
• Application Number:
  US12/463,386
• Publication Number:
  US 20090217142A1
• Time in Patent Office: 2,026 Days
• Field of Search: 714/774
• US Class Current: 714/774
• CPC Class Codes: H03M 13/256 with trellis coding, e.g. with convolutional codes and TCM
• CPC Class Codes: H03M 13/258 with turbo codes, e.g. Turbo Trellis Coded Modulation [TTCM]
• CPC Class Codes: H03M 13/2957 Turbo codes and decoding
• CPC Class Codes: H03M 13/3905 Maximum a posteriori probability [MAP] decoding or approximations thereof based on trellis or lattice decoding, e.g. forward-backward algorithm, log-MAP decoding, max-log-MAP decoding
• CPC Class Codes: H03M 13/3988 for rate k/n convolutional codes, with k>1, obtained by convolutional encoders with k inputs and n outputs
• CPC Class Codes: H03M 13/6362 by puncturing
• CPC Class Codes: H03M 13/6516 Support of multiple code parameters, e.g. generalized Reed-Solomon decoder for a variety of generator polynomials or Galois fields

Abstract

Rate control adaptable communications. A common trellis is employed at both ends of a communication system (in an encoder and decoder) to code and decode data at different rates. The encoding employs a single encoder whose output bits may be selectively punctured to support multiple modulations (constellations and mappings) according to a rate control sequence. A single decoder is operable to decode each of the various rates at which the data is encoded by the encoder. The rate control sequence may include a number of rate controls arranged in a period that is repeated during encoding and decoding. Either one or both of the encoder and decoder may adaptively select a new rate control sequence based on a variety of operational parameters including operating conditions of the communication system, a change in signal to noise ratio (SNR), etc.

Claims

1. An apparatus comprising:

a metric generator, coupled to the decoder, that is operative to calculate a plurality of metrics for a respective symbol of a signal received from a communication channel based on one of a first plurality of rate controls or one of a second plurality of rate controls that corresponds to the respective symbol;

a decoder, that is coupled to the metric generator, that is configured to decode the signal using the first plurality of rate controls and the second plurality of rate controls to generate estimates of information bits encoded within symbols of the signal including using the plurality of metrics to decode the respective symbol;

a rate control sequencer, coupled to the decoder, that is configured to provide the first plurality of rate controls to the decoder, wherein;

the decoder firstly is configured to decode a first portion of the signal using the first plurality of rate controls such that each respective symbol within the first portion of the signal is decoded based on a respective one of the first plurality of rate controls;

based on a change of a signal to noise ratio (SNR) corresponding to the communication channel, the rate control sequencer is configured to provide the second plurality of rate controls to the decoder; and

the decoder secondly is configured to decode a second portion of the signal that follows the first portion of the signal using the second plurality of rate controls such that each respective symbol within the second portion of the signal is decoded based on a respective one of the second plurality of rate controls.

2. The apparatus of claim 1, wherein the rate control sequencer further comprising:

a storage module configured to store the first plurality of rate controls, wherein the first plurality of rate controls is a predetermined plurality of rate controls, and the second plurality of rate controls is an adaptively changed version of the predetermined plurality of rate controls.

3. The apparatus of claim 1 further comprising:

a satellite receiver, an cellular phone, or a set top box receiver.

4. The apparatus of claim 1 further comprising:

the metric generator configured to calculate a first plurality of metrics for a first symbol of the signal based on a first rate control indicating a first constellation and a first corresponding mapping of the first symbol, wherein the metric generator is operative to calculate a second plurality of metrics for a second symbol of the signal based on a second rate control indicating a second constellation and a second corresponding mapping of the second symbol, and the decoder employs the first plurality of metrics and the second plurality of metrics to decode the first symbol and the second symbol, respectively.

5. The apparatus of claim 1 further comprising:

the metric generator configured to;

calculate a first plurality of metrics for a first symbol of the signal based on a first rate control indicating a constellation and a first corresponding mapping of the first symbol; and

wherein;

calculate a second plurality of metrics for a second symbol of the signal based on a second rate control indicating the constellation and a second corresponding mapping of the second symbol; and

the decoder is configured to employ the first plurality of metrics and the second plurality of metrics to decode the first symbol and the second symbol, respectively.

6. The apparatus of claim 1 further comprising:

the apparatus configured to receive from at least one additional apparatus coupled to the apparatus via the communication information related to the change of the SNR corresponding to the communication channel.

7. The apparatus of claim 1, wherein the decoder further comprising:

a variable code rate decoder configured to;

decode a first symbol of the signal based on a first rate control indicating a first code rate of the first symbol; and

decode a second symbol of the signal based on a second rate control indicating a second code rate of the second symbol.

8. The apparatus of claim 1 further comprising:

a communication device that is implemented within at least one of a satellite communication system, a high definition television (HDTV) communication system, a cellular communication system, a microwave communication system, a point-to-point radio communication system, a uni-directional communication system, a bi-directional communication system, or a one to many communication system.

9. A method for execution by a communication device, the method comprising:

employing a metric generator to calculate a plurality of metrics for a respective symbol of a signal received from a communication channel based on one of a first plurality of rate controls or one of a second plurality of rate controls that corresponds to the respective symbol;

employing a decoder, coupled to the metric generator, to decode the signal using the first plurality of rate controls and the second plurality of rate controls to generate estimates of information bits encoded within symbols of the signal including using the plurality of metrics to decode the respective symbol of the signal;

employing a rate control sequencer, coupled to the decoder, to provide the first plurality of rate controls to the decoder;

employing the decoder firstly to decode a first portion of the signal using the first plurality of rate controls such that each respective symbol within the first portion of the signal is decoded based on a respective one of the first plurality of rate controls;

based on a change of a signal to noise ratio (SNR) corresponding to the communication channel, employing the rate control sequencer to provide the second plurality of rate controls to the decoder; and

employing the decoder secondly to decode a second portion of the signal that follows the first portion of the signal using the second plurality of rate controls such that each respective symbol within the second portion of the signal is decoded based on a respective one of the second plurality of rate controls.

10. The method of claim 9, wherein:

the first plurality of rate controls is a predetermined plurality of rate controls; and

the second plurality of rate controls is an adaptively changed version of the predetermined plurality of rate controls.

11. The method of claim 9, wherein the communication device is a satellite receiver, an cellular phone, or a set top box receiver.

12. The method of claim 9 further comprising:

employing the metric generator to calculate a first plurality of metrics for a first symbol of the signal based on a first rate control indicating a first constellation and a first corresponding mapping of the first symbol;

employing the metric generator to calculate a second plurality of metrics for a second symbol of the signal based on a second rate control indicating a second constellation and a second corresponding mapping of the second symbol; and

employing the first plurality of metrics and the second plurality of metrics to decode the first symbol and the second symbol, respectively.

13. The method of claim 9 further comprising:

employing the metric generator to calculate a first plurality of metrics for a first symbol of the signal based on a first rate control indicating a constellation and a first corresponding mapping of the first symbol;

employing the metric generator to calculate a second plurality of metrics for a second symbol of the signal based on a second rate control indicating the constellation and a second corresponding mapping of the second symbol; and

employing the first plurality of metrics and the second plurality of metrics to decode the first symbol and the second symbol, respectively.

14. The method of claim 9 further comprising:

receiving from at least one additional apparatus coupled to the apparatus via the communication channel information related to the change of the SNR corresponding to the communication channel.

15. The method of claim 9 further comprising:

employing the decoder to decode a first symbol of the signal based on a first rate control indicating a first code rate of the first symbol; and

employing the decoder to decode a second symbol of the signal based on a second rate control indicating a second code rate of the second symbol.

16. The method of claim 9, wherein the communication device is implemented within at least one of a satellite communication system, a high definition television (HDTV) communication system, a cellular communication system, a microwave communication system, a point-to-point radio communication system, a uni-directional communication system, a bi-directional communication system, or a one to many communication system.

17. A method for execution by a communication device, the method comprising:

receiving a signal transmitted to the communication device from at least one additional communication device via a communication channel;

employing a metric generator, coupled to the decoder, to calculate a first plurality of metrics for a first symbol of the signal based on a first rate control indicating a first constellation and a first corresponding mapping of the first symbol;

employing the metric generator to calculate a second plurality of metrics for a second symbol of the signal based on a second rate control indicating a second constellation and a second corresponding mapping of the second symbol;

employing a decoder to decode the signal, based on a first plurality of rate controls and a second plurality of rate controls to generate estimates of information bits encoded within symbols of the signal including employing the first plurality of metrics and the second plurality of metrics to decode the first symbol and the second symbol, respectively;

employing a rate control sequencer, coupled to the decoder, to provide the first plurality of rate controls to the decoder;

employing the decoder firstly to decode a first portion of the signal using the first plurality of rate controls such that each respective symbol within the first portion of the signal is decoded based on a respective one of the first plurality of rate controls;

receiving, from the at least one additional communication device coupled to the communication device via the communication channel, information related to a change of a signal to noise ratio (SNR) corresponding to the communication channel;

based on the change of the SNR corresponding to the communication channel, employing the rate control sequencer to provide the second plurality of rate controls to the decoder; and

employing the decoder secondly to decode a second portion of the signal that follows the first portion of the signal using the second plurality of rate controls such that each respective symbol within the second portion of the signal is decoded based on a respective one of the second plurality of rate controls.

18. The method of claim 17, wherein the communication device is a satellite receiver, an cellular phone, or a set top box receiver.

19. The method of claim 17 further comprising:

employing the decoder to decode a first symbol of the signal based on a first rate control indicating a first code rate of the first symbol; and

employing the decoder to decode a second symbol of the signal based on a second rate control indicating a second code rate of the second symbol.

20. The method of claim 17, wherein the communication device is implemented within at least one of a satellite communication system, a high definition television (HDTV) communication system, a cellular communication system, a microwave communication system, a point-to-point radio communication system, a uni-directional communication system, a bi-directional communication system, or a one to many communication system.