Detector and method for estimating data probability in a multi-channel receiver

• US 7,813,438 B2
• Filed: 09/11/2008
• Issued: 10/12/2010
• Est. Priority Date: 07/07/2004
• Status: Active Grant

• Current Assignee: University of Utah Research Foundation (State of Utah)
• Original Assignee: University of Utah Research Foundation (State of Utah)
• Inventors: Shi, Zhenning, Zhu, Haidong, Laraway, Stephen Andrew, Farhang-Boroujeny, Behrouz
• Primary Examiner(s): Ghayour; Mohammad H
• Assistant Examiner(s): Vlahos; Sophia
• Application Number:
  US12/209,143
• Publication Number:
  US 20090003483A1
• Time in Patent Office: 761 Days
• Field of Search: 375/252, 375/262, 375340-341, 375/362, 375/136, 375/144, 375/346
• US Class Current: 375/262
• CPC Class Codes: H04B 1/7105 Joint detection techniques, e.g. linear detectors
• CPC Class Codes: H04L 1/005 Iterative decoding, including iteration between signal detection and decoding operation
• CPC Class Codes: H04L 1/0052 Realisations of complexity reduction techniques, e.g. pipelining or use of look-up tables
• CPC Class Codes: H04L 1/0631 Receiver arrangements

Abstract

A detector and method for estimating channel data probability in a multi-user or multiple-input multiple-output communication system includes summing conditional bit probabilities conditioned on hypothetical channel data patterns over stochastically selected hypothetical channel data patterns. Various detailed hardware structures and circuits are also described.

Claims

1. A detector for estimating channel data probabilities in a multi-channel communication system comprising:

a receiver configured to receive a multi-channel signal and output an observed signal;

a Gibbs sampler circuit coupled to the receiver and configured to generate stochastically selected channel data hypotheses based in part on the observed signal and a channel model; and

a channel data probability estimator coupled to the receiver and coupled to the Gibbs sampler circuit and configured to estimate channel data probabilities by summing conditional data probabilities conditioned on the observed signal and the stochastically selected channel data hypotheses.

2. The detector of claim 1, wherein the Gibbs sampler circuit further comprises a Markov chain Monte Carlo simulator coupled to the receiver and configured to generate channel data samples from an auxiliary distribution wherein transition probabilities are based in part on the observed signal.

3. The detector of claim 2 wherein the auxiliary distribution is a uniform distribution.

4. The detector of claim 2 wherein the auxiliary distribution is based on the channel model using a signal to noise ratio below an estimated operating signal to noise ratio of the multi-channel communication system.

5. The detector of claim 1 wherein the channel data probability estimator further comprises a log likelihood ratio estimator coupled to the channel data probability estimator and configured to estimate channel data log likelihood ratios from the channel data probabilities.

6. The detector of claim 1 further comprising a decoder coupled to the channel data probability estimator and configured to exchange extrinsic information with the channel data probability estimator.

7. A method for estimating channel data likelihoods in a multi-channel communications system comprising:

receiving a multi-channel communications signal at a multi-channel communications system receiver to form an observed signal;

generating stochastically-selected channel data hypotheses using a Markov chain Monte Carlo simulation within electronic circuitry coupled to the receiver;

determining conditional bit probabilities conditioned on the stochastically-selected channel data hypotheses and the observed signal within the electronic circuitry; and

forming a channel data likelihood based on the conditional bit probabilities within the electronic circuitry, wherein forming a channel data likelihood comprises summing the conditional bit probabilities to form channel data bit probabilities corresponding to each possible value for a channel data bit .

8. The method of claim 7, wherein forming a channel data likelihood comprises:

determining a log likelihood ratio for the channel data bit using the channel data bit probabilities.

9. The method of claim 7, wherein forming a channel data likelihood comprises:

finding a maximum conditional bit probability for each possible value of a channel data bit; and

approximating a log likelihood ratio for the channel data bit using the maximum conditional bit probability for each possible value of the channel data bit.

10. The method of claim 7, wherein generating stochastically-selected channel data hypotheses using a Markov chain Monte Carlo simulation comprises setting state transaction probabilities for the Markov chain Monte Carlo simulation based on the observed signal.

11. The method of claim 7, wherein generating stochastically-selected channel data hypotheses using a Markov chain Monte Carlo simulation comprises setting state transaction probabilities based on an auxiliary distribution.