Sürekli Faz Kiplemesi İçin Düşük Karmaşıklığa Sahip Alıcılar

Abstract

Continuous Phase Modulation (CPM) is preferred in numerous power and band-limited communication systems for its constant envelope and spectral effciency. Despite its highly attractive spectral properties, maximum-likelihood detection of CPM over the frequency-selective multipath fading channels can bring impractical complexity issues because of the intensive search over a single super trellis which combines the effects of the modulation and the multipath channel. Application of the reduced-state trellis search algorithms results in lower complexity but the computational load could still be prohibitively large to obtain high performance in long channel impulse responses. This thesis investigates practical implementations of a maximum likelihood sequence estimator (MLSE) receiver for CPM based on Laurent decomposition using Viterbi algorithm. On the other hand, the decomposition of the CPM signal in the Walsh signal space that brings the less hardware requirement is investigated. For both of the receiver structure, some suboptimal versions are proposed to reduce the receiver complexity and the performance comparison is done for additive white Gaussian noise channels via MATLAB simulation.