Adaptive Modulation, Adaptive Coding, and Power Control for Fixed Cellular Broadband Wireless Systems

Abstract The wireless channel is characterized by large statistical variations, which results in wide variations in its response. If the system is designed to meet the worst conditions of the channel, the throughput will be very small and the efficiency will degrade. On the other hand, if the system is designed to track the channel variations, it will yield a larger throughput. In this work, we investigate the advantage of using adaptive modulation, adaptive coding, and power control to track the channel variations in broadband fixed wireless access system. When the channel condition improves, the system will select a larger constellation size for modulation and a suitable coding scheme. When the channel degrades due to fading, the system will resort to a smaller constellation size for modulation and a powerful coding scheme. This approach yields larger throughput than using fixed modulation all the time. Power control adds a relatively small improvement in the throughput when combined with adaptive modulation and adaptive coding.