Incoherent estimation on co-channel interference probability for microcellular systems

Prasad and Kegel (1993) offered an approximate analysis of the co-channel interference (CCI) probability for a microcellular system that has multiple shadowed Rayleigh interfering signals and a shadowed Rician desired signal. In that analysis, coherent addition of summing multiple interfering signals was assumed. However, it has been shown that incoherent addition is a more realistic assumption (Prasad and Kegel 1991). In the present paper two approaches-approximation and exact analysis-for calculating the CCI probability under incoherent addition are given. The approximate analysis is extended from the macrocellular case. The exact analysis, newly developed in the present paper, is then used to check the accuracy of the approximation. It is shown that the results of the incoherent approximate analysis differ by an amount of 20~30%. In addition, the authors explore the effect of correlation between the shadowing interferers. They find that in a shadowed-Rician/shadowed-Rayleigh channel, the effect of this kind of correlation increases the CCI probability for cases having a small spread in shadowing and large reuse distance. But if the spread in shadowing is large, the result can be just the opposite-this correlation yields a better performance. It is also found that in a shadowed-Rayleigh (desired)/shadowed-Rayleigh (interfering) channel, regardless of degree of spread in shadowing, this correlation seems always to improve the performance