An adaptive backoff and dynamic clear channel assessment mechanisms in IEEE 802.15.4 MAC for wireless body area networks

摘要

The low power connectivity and short distance communication qualities of the IEEE 802.15.4 standard suits its application in wireless body (personal) area networks (WBAN). IEEE 802.15.4 protocol use carrier sense multiple access and collision avoidance (CSMA-CA) medium access control (MAC) mechanism for aperiodic data communication; however, it faces performance degradation with a gradual increase in the number of network devices. Performance challenges arise due to; several heterogeneous and dynamic packet sources sharing limited resources during contention in a finite backoff period, association delay, and traffic channel access through clear channel assessment (CCA) algorithms. Due to such constraints, channel conditions increase packet collision and queuing delay, which raises power demand and impedes performance indicators, such as throughput, packet delivery ratio (PDR), and end to end (E2E) delay. This article proposes an alternative combination of the backoff and CCA adaptation mechanisms to improve WBAN performance characteristics in a highly dynamic environment considering network residue energy, PDR, throughput, and E2E delay. We use the Markov model to demonstrate a theoretical analysis of the proposed CSMA-CA MAC mechanism. A comparative study shows the proposed methods outperform conventional protocol in PDR, throughput, and reduced E2E delay by 13.1%, 21.44%, and 41.13%, respectively, where energy efficiency drops by 0.43%.