Knowledge-based exponential backoff scheme in IEEE 802.15.4 MAC

Abstract

In wireless personal area network, a channel is shared by a number of nodes. Therefore packet collision may take place and it degrades the throughput performance. To improve the throughput of slotted CSMA/CA in IEEE 802.15.4, we propose knowledge-based exponential backoff (KEB) scheme for enhancing channel utilization solely based on the locally available channel state information. In addition, we propose an analytical model of slotted channel access mechanism with finite retry and derive the theoretical throughput limit. In simulation experiments, we show that the existing MAC scheme, binary exponential backoff (BEB) scheme, operates very far from the theoretical limits due to increased time for negotiating channel access. Also performance results indicate that KEB shows significant improvement in throughput performance over BEB with the knowledge of the network status. © 2008 Springer Berlin Heidelberg.