We evaluate using simulation studies the performance of several schemes for combining base station antenna array signals in wireless direct sequence code-division multiple access (DS/CDMA). The results indicate that under certain assumptions, on multiple access interference statistics, the probability of error of modified rank test (MRT) is lower than that of equal gain combining (EGC), if a few high power interfering users are present along with a low power user of interest. If there are a moderately large number of users, and if the received power of all the users are nearly the same, then EGC out performs MRT. In fact, under this condition, the performance of EGC is close to that of the optimal likelihood ratio test (LRT).
Gowda, C. H., Annampedu, V. and Viswanathan, R.. "Diversity Combining in Antenna Array Base Station Receiver for DS/CDMA System." (Jul 1998).