KARHUNEN-LOEVE EXPANSION OF THE WSSUS CHANNEL OUTPUT AND ITS APPLICATION TO EFFICIENT SIMULATION

This paper derives a Karhunen-Loeve (K-L) expansion of the time-varyin g output of a multipath Rayleigh fading wide-sense-stationary uncorrel ated-scattering (WSSUS) channel. It is shown that under the same mean- squared error condition, the number of terms required by the truncated K-L expansion is less than that of the series expansion obtained by u sing the discrete-path approximation of the channel so that simulation using the K-L expansion is more efficient. This computational advanta ge becomes more significant as higher simulation accuracy is required. The derived K-L expansion is applied to develop an efficient simulati on technique for digital transmission over a multipath Rayleigh fading WSSUS channel using an optimum receiver. We show that the proposed te chnique requires shorter computation time than two other known simulat ion techniques.