Performance gain of S-macrodiversity system in log-normal shadowed Rayleigh fading channel

In a cellular system, the effects of the surrounding buildings, terrain and trees cause a large variation in signal strength received by a mobile unit. Analyses have shown that this variation degrades the system performance and the resulting degradation is usually called the shadowing effect. We can achieve a more uniform coverage and reduce the shadowing effect by using two or more cites to serve a connection; the probability of two bad paths is obviously smaller than that of one. This technique, a large-scaled selection space diversity, is usually called macrodiversity. The performance is usually represented in terms of cochannel interference (CCI) probability, which is defined as the probability that the desired signal level is less than the required receiver threshold due to excessive interference. Traditionally, three kinds of link measurement have been proposed: (i) S/I-macrodiversity; (ii) S-macrodiversity; (iii) (S+1)-macrodiversity. Here we analyse the performance gain of S-macrodiversity