Communication system model for information rate evaluation of differential detection over time-varying channels

Krusevac, Z.B., Rapajic, P.B. and Kennedy, R.A. (2008) Communication system model for information rate evaluation of differential detection over time-varying channels. IET Communications, 2 (10). pp. 1301-1310. ISSN 1751-8628

Abstract

A communication system model for mutual information performance analysis of multiple-symbol differential M-phase shift keying over time-correlated, time-varying flat-fading communication channels is developed. This model is a finite-state Markov (FSM) equivalent channel representing the cascade of the differential encoder, FSM channel model and differential decoder. A state-space approach is used to model channel phase time correlations. The equivalent model falls in a class that facilitates the use of the forward backward algorithm, enabling the important information theoretic results to be evaluated. Using such a model, one is able to calculate mutual information for differential detection over time-varying fading channels with an essentially finite time set of correlations, including the Clarke fading channel. Using the equivalent channel, it is proved and corroborated by simulations that multiple-symbol differential detection preserves the channel information capacity when the observation interval approaches infinity.

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