Traffic differentiation and scheduling for QoS support in vehicular sensor networks

The IEEE 802.15.4 is widely used next-generation standard protocol in many applications utilizing wireless sensor networks (WSNs) especially in vehicular sensor networks (VSNs). However, currently differentiation and scheduling mechanisms are not provided in IEEE 802.15.4 specification to improve the quality of service (QoS) for delay-sensitive and critical events. In this paper, multiple scheduling algorithms such as FIFO, Priority queue, WRR and DWRR are integrated in compliance with IEEE 802.15.4 to improve the throughput, enhance the bandwidth utilization rate and perform fast processing and delivery for urgent data traffic. we divide the standard traffic into various types of data on the basis of different QoS requirements such as real-time fixed data packets generation on periodic basis, real-time variable size data packets generation on periodic basis, non real-time variable size data packets and best effort. The mandatory QoS service flow parameters are defined for each type of traffic according to its time-criticality and delay sensitivity.