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US 8,045,604 B2Granted
Estimation of log-likelihood using constrained markov-chain monte carlo simulation
AssigneeUniversity of Utah Research Foundation
InventorsBehrouz Farhang-Boroujeny, Salam Akoum
Life of this patent
Estimating the term…
Abstract
Log likelihood ratios for data bits transmitted in a multi-dimensional signal are estimated using multiple Markov chain Monte Carlo simulations (MCMC). The MCMC simulations can include constraining symbols based on a most-likely symbol to improve the likelihood of finding distances for non-most-likely symbols. The log likelihood ratios can be calculated based on distances of the most-likely symbol and the non-most-likely symbols.
Claims15
A method of estimating log likelihood ratios in a receiver comprising:
- receiving using a receiver a multi-dimensional signal comprising a plurality of transmitted data bits;
- forming a first symbol estimate having a first distance from an observation of the multi-dimensional signal wherein the first symbol estimate comprises a plurality of first data bits;
- initializing a plurality of Markov chain Monte Carlo simulations using a plurality of differing second symbol estimates each comprising a plurality of second data bits, wherein each one of the plurality of second symbol estimates is constrained so that a differing one of the plurality of second data bits is inverted relative to a corresponding one of the first data bits;
- running the plurality of Markov chain Monte Carlo simulations to stochastically-search for constrained minimum second distances corresponding to the second data bits;
- and
- calculating a plurality of log likelihood ratios corresponding to each of the plurality of transmitted data bits using the first distance and the constrained minimum second distances.
3 more elements
A receiver comprising:
- a signal storage having an input configured to accept digital samples of a multi-dimensional signal comprising a plurality of transmitted data bits;
- a symbol estimator coupled to the signal storage and configured to estimate a first symbol estimate from the digital samples;
- a plurality of Markov chain Monte Carlo simulators coupled to the signal storage and configured to stochastically search for corresponding ones of a plurality of second symbol estimates, wherein each one of the second symbol estimates is constrained so that a differing bit is inverted relative to a corresponding bit of the first symbol estimate;
- and
- a log likelihood calculator coupled to the symbol estimator and the plurality of Markov chain Monte Carlo simulators and configured to output log likelihood ratio estimates corresponding to each of the plurality of transmitted data bits.
2 more elements
Dependencies are inferred from the claim text.