Performance Evaluation of Five New Adaptive Contention Slot Allocators for IEEE 802.16 Based Systems

A reservation based medium access control (MAC) protocol has been adopted by the IEEE 802.16 standard as the basic protocol for data communication within the upstream channel. In this paper, we propose the following five new contention slot allocators (CSA) for the IEEE 802.16 MAC protocol: Forced-CSA, Variable-CSA, Multicast-CSA, Collision Free-CSA and CDMA-CSA. The new techniques dynamically fit the number of contention slots needed to solve collisions according to the current traffic load, considerably improving overall system performance. The CSAs introduced in this paper indicate that the mean access delay could be reduced up to 75% compared with the currently adopted method by the IEEE 802.16 MAC protocol, called simple-CSA. A performance evaluation of our five CSA schemes is presented and compared with previous CSA schemes, simple-CSA and IEEE 802.14-CSA. Obtained results turned out to be closer to the maximum estimated throughput than currently used methods.