CQS: A Conflict-free Query Scheduling Approach in Wireless Sensor Networks

Conflict-free real-time query scheduling is one of the difficult tasks in Wireless Sensor Networks (WSNs). To accommodate this claim, we propose a Conflict-free Query Scheduling Approach (CQS) in WSNs. CQS works with three new schedulers, a Non-preemptive Conflict-free Query Scheduler(NCQS), Pre-emptive Conflict-free Query Scheduler (PCQS), and Advanced Conflict-free Query Scheduler (ACQS). Our simulation results indicate that NCQS results in high real-time performance but response time is high for high priority queries due to priority inversion. Whereas, PCQS supports preemption which can reduce the priority inversion. ACQS combines the advantages of both NCQS and PCQS and enhances the adequacy admitting affair that is the end-to-end deadlines of queries. The simulation results also indicate better performance of our approach as compared to the existing approaches. The simulation results are validated through NS-2.