Maximum likelihood decoding of QAM signals in Markov modulated fading channels

Iain B. Collings*, Andrew Logothetis, Vikram Krishnamurthy

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference proceeding contribution

Abstract

This paper presents a new decoder for quadrature-amplitude-modulated (QAM) signals transmitted through Markov modulated fading channels. Markov modulated channels arise in city environments when a direct line of sight is blocked intermittently, and for large area coverage mobile cells where the channel has large variations in fading statistics. The channel is modelled as a time varying AR process, with coefficients which depend on a Markov chain. An optimal batch algorithm is presented which provides estimates of the channel and the digital signal. This is achieved by optimally coupling a Viterbi algorithm and a Kalman filter. The optimality is demonstrated via the Expectation Maximization algorithm. In addition, a sub-optimal on-line algorithm has been derived. By considering the channel to be Markov modulated, benefits can be gained over standard techniques which assume fixed fading statistics.

Original languageEnglish
Title of host publicationIEEE Signal Processing Workshop on Signal Processing Advances in Wireless Communications, SPAWC
Place of PublicationPiscataway, N.J.
PublisherInstitute of Electrical and Electronics Engineers (IEEE)
Pages405-408
Number of pages4
ISBN (Electronic)0780339452
ISBN (Print)0780339444
DOIs
Publication statusPublished - Apr 1997
Externally publishedYes
EventProceedings of the 1997 1st IEEE Signal Processing Workshop on Signal Processing Advances in Wireless Communications, SPAWC'97 - Paris, Fr
Duration: 16 Apr 199718 Apr 1997

Other

OtherProceedings of the 1997 1st IEEE Signal Processing Workshop on Signal Processing Advances in Wireless Communications, SPAWC'97
CityParis, Fr
Period16/04/9718/04/97

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