Factor graphs and MCMC approaches to iterative equalization of nonlinear dispersive channels

In this work, equalization for nonlinear dispersive channels is considered. Nonlinear communication channels can lead to significant degradations when nonlinearities are not taken into account at either the receiver or the transmitter. In many cases, the nonlinearity of the channel precludes the use of spectrally efficient signaling schemes to achieve high data-rates and the bandwidth efficiency. Satellite channel is a typical case of nonlinear channel that needs to be used efficiently. We develop two novel equalization strategies for a general class of nonlinear channels. Both strategies are based on iterating between decoding and equalization, termed as iterative equalization. The first strategy is a factor graph based equalizer that converts the nonlinear channel equalization problem into forward-backward algorithm on hidden Markov model (HMM). The equalizer is implemented via the sum-product algorithm on the factor graph representation of the channel and receiver blocks. The second equalization strategy is based on Markov chain Monte Carlo (MCMC) methods. We typecast the problem of executing forward-backward algorithm on HMM into an MCMC domain problem and develop four different types of MCMC equalizers.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2006

Author dc:creator

• Kashif, Faisal M. (Faisal Mahmood)

Advisor dc:contributor.advisor

• Moe Z. Win.

• Electrical Engineering and Computer Science.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/38229

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/38229