A Delay Sensitive Time Slots Scheduling in Vehicular Sensor Networks

In Vehicular communication networks, a robust access mechanism is essential for the successful information exchange between vehicles and roadside unit, which keeps the vehicles being aware of surroundings thus improving driving safety and reduce traffic jam. In this paper, we first analyze the drawbacks of explicit GTS (Guaranteed Time Slots) allocation suggested by IEEE 802.15.4 draft and show the importance of a wise assignment scheme and efficient scheduler especially for high dynamic vehicular environment. Then, for a given number of vehicles requesting to access the roadside unit, we propose a Time-Sensitive Weighted Round Robin scheduler (TS-WRR) considering different service delay requirements, packets arrival rates and vehicles´ mobility levels. We also show the elaborate implementation procedure of TS-WRR by pseudocode. Numerical results show that our TS-WRR scheduler outperforms FCFS and WRR on the performance of transactions delay requirements guarantee and GTS utilization ratio in Vehicular Sensor Networks.