An investigation of wireless personal communication systems: microcell co-channel interference modelling and outage probability analysis

Cochannel interference in microcell radio systems is investigated. Two microcell cochannel interference models, at Rician/Rayleigh model and a Rician/Rayleigh-plus-log normal model, are presented. In the first model, the desired signal within a microcell experiences Rician fading while interfering signals from cochannel cells are subject to Rayleigh fading. In the second model, the cochannel interfering signals are subject to superimposed Rayleigh fading and log normal shadowing. Frequency selective multipath fading is considered in both models. The probability density function of the power ratio between the desired signal and composite interferers is derived. In evaluating the composite interference, both coherent and noncoherent interference addition are considered. Using the probability density function of the signal-to-interference ratio, expressions of the system outage probability are derived. Microcell systems are compared with medium/large cell systems in terms of the outage probability. It is shown that the former outperforms the latter. The effect of frequency selective multipath fading and that of shadowing on the outage probability are also observed