On coherent detection of MSK on a two-ray multipath fading channel

Abstract

Signals on a real mobile radio channel are affected by many various types of phenomenas. One of these phenomenas is multipath fading. In this paper a simple two-ray model of a multipath Fading channel is studied. The modulation used is Minimum Shift Keying (MSK). Furtheron white Gaussian noise is added to the received signal. The optimum coherent detector is the Maximum Likelihood (ML) detector and the performance of this detector is studled by means of minimum Euclidean distance and simulated bit error probability. Approximations of the ML detector are also studied. A linear detector optimum at large signal to noise ratios is also studied and the performance is given by means of error probability. It is assumed that measurements on the channel provides information of the channel parameters. Both error Free and erroneous measurements are considered. Numerical results are given for various channels and it is Found that the loss in signal power due to the channel is small when a ML detector is used. On the other hand for a linear detector the loss becomes significant for some channel parameters. It is also shown that the performance of the ML detector is quite insensitive to erroneous channel measurements.