Energy Efficient Conflict Free Query Scheduling For Wireless Sensor Networks
Pooja Kannadas1, S. Joshua Daniel2
1Pooja Kannadas, M.E. Student, Department of EEE, Hindusthan College of Engineering and Technology, Coimbatore-, India
2S.Joshua Daniel, Assistant Professor, Department of EEE, Hindusthan College of Engineering and Technology, Coimbatore, India.
Manuscript received on May 17, 2012. | Revised Manuscript received on June 22, 2012. | Manuscript published on June 30, 2012. | PP: 320-324 | Volume-1 Issue-5, June 2012. | Retrieval Number: E0528061512/2012©BEIESP

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Abstract: There is an increase in demand of high performance query services, with the emergence of high data rate applications. To meet this challenge we propose Dynamic Conflict-free Query Scheduling (DCQS), a novel scheduling technique for queries in wireless sensor networks. In contrast to earlier Time Division Multiple Access (TDMA) designed for query services in wireless sensor networks. DCQS has several unique features. First, it optimizes the query performance through conflict-free transmission scheduling based on the temporal properties of queries in wireless sensor networks. Second, it can adapt to workload changes without explicitly reconstructing the transmission schedule. Furthermore, DCQS also provides predictable performance in terms of the maximum achievable query rate. The nodes operate over the time-varying wireless channel whose quality significantly fluctuates over time due to fading and interference. Such time-varying nature of wireless channel imposes many constraints in designing an energy-efficient transmission scheme. In this work, we derive a tight bound on the maximum query rate achieved under DCQS. Such a bound is of practical importance since it can be used to prevent network overload. NS2 simulations demonstrate that energy efficient DCQS significantly outperforms 802.11 in terms of energy efficiency, over head, query latency, and throughput, thereby increasing the network life time. 
Keywords: DCQS, TDMA, NS2