Modified beacon-enabled IEEE 802.15.4 MAC for energy critical and bandwidth

IEEE 802.15.4 is a standard uniquely designed for low data rate wireless personal area networks (WPANs). It also supports time and rate sensitive applications. For low-latency applications or applications requiring specific data bandwidth, the PAN coordinator may dedicate portions of the active superframe to that application. These portions are called guaranteed time slots (GTSs). The coordinator allocates GTSs for nodes on a first-come-first-served (FCFS) basis. This fixed FCFS scheduling service offered by the standard may not satisfy the time constraints of time-sensitive transactions with delay deadlines and limit the node number request for GTS slot. The unacknowledged nodes will be in CSMA/CA manner, which would cause energy depletion disequilibrium and decrease the network lifetime. To extend the lifetime of the WPAN, we propose a backward compatible energy efficient 802.15.4 MAC protocol to overcome those limitations for beacon-enabled sensor networks. First the proposed protocol simplifies the GTS request steps by modifying data frame header to request GTS allocation for different traffic load instead of the GTS request command. Then we allocate GTS slot to different nodes in a round-robin pattern. Such implicit request can efficiently enhance the performance of wireless sensor network. Extensive ns-2 simulations are used to verify the analysis. Copyright © 2013 Binary Information Press.