Performance evaluation of sum-of-cisoids Rice/Rayleigh fading channel simulators with respect to the bit error probability

摘要

Sum-of-cisoids (SOC) processes provide an important framework for the modeling and simulation of multipath fading channels. In this paper, we analyze the performance of SOC Rice/Rayleigh narrowband fading channel simulators with respect to the bit error probability (BEP) of quadrature phase shift keying (QPSK) and differential phase shift keying (DPSK) systems with both coherent and noncoherent demodulation. For the BEP of coherent QPSK and DPSK, exact analytical expressions are derived, which provide insight into the influence of the number of propagation paths and the path gains on the system performance. It will be shown that at least 10 multipath components are required to guarantee that the absolute value of the relative error of the BEP is less than 5%. Regarding the BEP of noncoherent DPSK, we show analytically and by simulations that the system performance reacts very sensitively to the model error caused by an imperfect computation of the channel simulator's Doppler frequencies. Our study is not only important for the performance evaluation of SOC-based channel simulators but also for the performance evaluation of QPSK and DPSK systems in the presence of a limited number of scatterers. Especially for a small number of propagation paths with unbalanced path gains, where the central limit theorem does not apply, the derived analytical expressions for the BEP reveal their full importance.