Constant bit rate packets transmission in IEEE 802.15.4 LR-WPANs

In IEEE 802.15.4 LR-WPANs, quality-of-service (QoS) is supported by using the guaranteed time slots (GTS) to transmit real-time packets, where a LR-WPAN device does not need to contend for channel. Requests of GTS are allocated based on the first-come-first-service policy in the PAN coordinator. However, with the increasing of multimedia applications, this original design has suffered from a lack of priority mechanism to support transmission of real-time packets. In this paper, we propose a non-preemptive priority-based polling scheme for the GTS allocation in IEEE 802.15.4 LR-WPANs. The proposed scheme can ensure the connections with higher priority can transmit real-time packets faster. The simulations show that the proposed scheme can achieve more GTS allocations, higher throughput, better bandwidth utilization and lower packets access delay time.