An Improvement of the Slotted CSMA/CA Algorithm with Multi-level Priority Strategy and Service Differentiation Mechanisms

It is the fact that IEEE 802.15.4 protocol does not support any service of priority scheduling mechanism and there are some shortages existing in the slotted CSMA/CA algorithm. In view of the different types of priority and the defects of the original CSMA/CA algorithm, a kind of CSMA/CA algorithm with multi-level priority strategy and service differentiation mechanisms is proposed in this paper. What´s more, in order to provide multi-level differentiation service, different BE and CW are used. Four types of priority are assumed, there are high, medium, low and normal priority and they are assigned depend on current state of the network by CSMA/CA algorithm. In the end, it is proved that the proposed algorithm performs better than the original one in the aspects of the throughput, network delay and the probability of successfully access to channel using network simulator OPNET.