Broadcasting, Coverage, Energy Efficiency and Network Capacity in Wireless Networks
thesisposted on 13.03.2013, 11:14 by Shagufta Henna
Broadcasting, coverage, duty cycling, and capacity improvement are some of the important areas of interest in Wireless Networks. We address different problems related with broadcasting, duty cycling, and capacity improvement by sensing different network conditions and dynamically adapting to them. We propose two cross layer broadcasting protocols called CASBA and CMAB which dynamically adapt to network conditions of congestion and mobility. We also propose a broadcasting protocol called DASBA which dynamically adapts to local node density. CASBA, CMAB, and DASBA improve the reachability while minimizing the broadcast cost. Duty cycling is an efficient mechanism to conserve energy in Wireless Sensor Networks (WSNs). Existing duty cycling techniques are unable to handle the contention under dynamic traffic loads. Our proposed protocol called SA-RI-MAC handles traffic contention much more efficiently than RI-MAC without sacrificing the energy efficiency. It improves the delivery ratio with a significant reduction in the latency and energy consumption. Due to limited battery life and fault tolerance issues posed by WSNs, efficient methods which ensure reliable coverage are highly desirable. One solution is to use disjoint set covers to cover the targets. We formulate a problem called MDC which addresses the maximum coverage by using disjoint set covers S1 and S2. We prove that MDC is NP-complete and propose a √n-approximation algorithm for the MDC problem to cover n targets. The use of multi-channel MAC protocols improves the capacity of wireless networks. Efficient multi-channel MAC protocols aim to utilize multiple channels effectively. Our proposed multi-channel MAC protocol called LCV-MMAC effectively utilizes the multiple channels by handling the control channel saturation. LCV-MMAC demonstrates significantly better throughput and fairness compared to DCA, MMAC, and AMCP in different network scenarios.