Partial Response Signaling with a Maximum Likelihood Sequence Estimation Receiver

Abstract

<p>This thesis evaluates a bandwidth efficient data transmitting system which is modelled as a PRS system. A maximum likelihood receiver implementing VA is assumed at the receiving end. An algorithm is developed to compute a fundamental performance parameter of the system, called the free distance. 99% energy bandwidth and intersymbol interference (lSI) degradation are used to measure the performance of the system. Nonlinear programming and minimax methods are applied to find the optimal channel codes under different criteria. Three different sets of optimal channel codes have been found; first, the worst-case channel codes in terms of lSI degradation, secondly, the minimum 99% energy bandwidth channel codes and finally the minimum 99% energy bandwidth channel with fixed lSI degradation constraint. Two PRS systems with different pulse shaping filter are considered. First, an ideal low pass filter with minimum Nyquist bandwidth is evaluated for channel lengths up to twelve. Then a spectral raised-cosine filter with roll-off factor equal to one is evaluated for channel lengths up to four. The two PRS systems show that a longer channel can have better performance in consideration of both bandwidth and lSI degradation. The raised cosine filter causes no performance penalty in narrow band channels.</p>