Analysis and improvement of contention access protocol in IEEE 802.15.4 star network

The wireless standard IEEE 802.15.4 is emerging as a key enabling technology for different wireless sensor network applications. IEEE802.15.4 supports a low data rate wireless sensor network with low power requirement. In this paper, we discuss the performance analysis of IEEE 802.15.4 MAC assuming star topology in the beacon enabled mode. We obtain analytical expressions for channel sensing probabilities and saturation throughput during the contention access period. We have included the packet discard analysis and validated the analytical expressions for these parameters using ns-2 simulation. Further, we also discuss the performance analysis of the MAC when the contention access mechanism of IEEE 802.15.4 is modified to have only one channel sensing. Finally, we discuss adaptation of the frame length for the case with one channel sensing.