Outage probability lower bound in CDMA systems with lognormal-shadowed multipath Rayleigh-faded and noise-corrupted links

The outage probability is one of the common metrics used in performance evaluation of cellular networks. In this paper, we derive a lower bound on the outage probability in CDMA systems where the communication links are disturbed by co-channel interference as well as additive noise. Each link is assumed to be faded according to both a lognormal distribution and a multipath Rayleigh distribution where the former represents the effect of shadowing while the latter represents the effect of short-term fading. The obtained lower bound is given in terms of a single-fold integral that can be easily computed using any modern software package. We present numerical results for the derived bound and compare them with the outage probability obtained by means of Monte Carlo simulations. Based on our results, we conclude that the proposed bound is relatively tight in a wide range of situations, particularly, in the case of small to moderate number of interferers and small to moderate shadowing standard deviation values.