Theoretical analysis for the downlink spectral efficiency of DS/CDMA cellular systems in Rayleigh fading environment

This paper presents an original exact analysis on the downlink spectral efficiency of DS/CDMA cellular systems in Rayleigh fading. We derive a new expression for the probability distribution functino of signal to interference plus noise ratio (SINR) which accordingly leads us to propose explicit closed forms of he spectral efficiency and average bit error rate in Rayleigh fading environment. The proposed closed forms are used to accurately investigage the effects of orthogonality, propagational condition, and channel noise on the overall efficiency.