Utilization-aware dynamic GTS allocation scheme in IEEE 802.15.4

IEEE 802.15.4 is a standard for low-rate wireless personal area network (LR-WPAN) and specifies medium access control (MAC) sub-layer and physical layer. MAC sub-layer in IEEE 802.15.4 provides a guaranteed time slot (GTS) to guarantee quality of service for applications requiring low latency or minimum data rate. However, since the maximum number of GTSs allowed in each superframe is limited up to seven in IEEE 802.15.4, efficient GTS allocation scheme is required to improve utilization of wireless resources and enhance quality of service. In this paper, we propose utilization-aware dynamic GTS allocation scheme for IEEE 802.15.4 to increase throughput and decrease data transmission latency. To obtain our objective, we introduce states and priorities of devices for GTS allocation. The state is utilized to determine priority of devices. PAN coordinator dynamically allocates GTSs to devices in descending order of their priorities. Performance of the proposed scheme is evaluated by simulation on C++. From the results, we confirm that our proposed scheme has better performance than the conventional IEEE 802.15.4 in terms of throughput and packet waiting time.