The Performance of Soft Macrodiversity Based on Maximal-Ratio Combining in Uncorrelated Rician Fading

In this paper, a simple product expression is found for the DPSK bit error rate of distributed base station systems affected by Rician fading. In this context, the received signals´ fading envelopes are Rician, uncorrelated among themselves, and in general have different variances and K factors. It is assumed that maximal-ratio diversity combining is applied. This bit error rate expression is extended to cover QAM modulation via approximation. Furthermore, a new product form of the probability density function (PDF) for a sum of non-central chi-square variates with different variances is derived, since it constitutes a necessary step in our analysis