Adaptive modulation, error control coding and microdiversity are well-known techniques that have been applied to wireless communication systems to overcome the fading process experienced by the transmitted signal. In this paper, we investigate the throughput returns due to the employments of various combinations of adaptive modulation, adaptive coding, and microdiversity in a broadband fixed wireless access cellular system.The results indicate that using adaptive modulation, coding, and maximal ratio combining (MRC) yields significant enhancements in spectral efficiency of the system. Second order selection combining has almost the same performance of MRC.