Discrete-time model for digital communications over a frequency-selective Rician fading WSSUS channel

Abstract

The paper develops a discrete-time model for digital communications via a frequency-selective Rician fading, wide-sense-stationary uncorrelated-scattering (WSSUS) channel with arbitrary pulse shaping and receiver filtering. As a special case, the discrete-time model is also applicable to a frequency-selective Rayleigh fading WSSUS channel. The model is expressed in the form Ξk = Nk + Σbk-mgm(t), where Ξk is the complex-valued receiver output, bk-m is the transmitted symbol, Nk is the complex-valued output noise due to AWGN, and gm(t) is the time-varying gain of bk-m. Statistical characteristics of Nk and gm(t) are derived. It is found that {Nk} is a zero-mean complex Gaussian sequence, and gm(t)s ∀ m follow a wide-sense-stationary, jointly complex Gaussian random process. Simple closed-form formulas computing statistical parameters of Nk and gm(t)s are derived. Several aspects regarding the use of the proposed model to analytic works and efficient computer simulations are discussed. Finally, three illustrative examples are given.