An enhanced superframe structure of IEEE 802.15.4 standard for adaptive data requirement

Abstract

In this paper, the superframe structure of IEEE 802.15.4 standard is improved to meet the adaptive data traffic requirements of hierarchical Wireless Sensor Networks (WSNs). In the IEEE 802.15.4 standard, sensor nodes send their data implicitly by using the Guaranteed Time Slots (GTS) to their PAN coordinator. The standard does not meet the adaptive data requirements of GTS requesting nodes. If requesting GTSs in an active period are more or less than the available limit, then either the requested nodes will not be entertained or GTSs remain underutilized. Consequently, it may cause unnecessary delays or poor GTS utilization. In this work, an Enhanced Superframe offering Adaptive Duty cycle (ESAD) is proposed. ESAD adapts the active period in accordance with the requested data. In addition, the actual size of GTS has been halved to accommodate more GTS requesting nodes. The shortest job first algorithm is applied to scrutinize the requested GTS nodes. Simulation results verify that the proposed scheme increases the link utilization, improves the data transmission, reduces the delay, and allows more nodes to transfer their data in a specified superframe.