Thesis

An Energy Efficient Clustering MAC and Routing Protocol in Wireless Sensor Networks

LEACH is a TDMA (Time-Division Multiple Access) based clustering MAC (Medium Access Control) protocol in wireless sensor networks. This protocol frequently forms clusters of nodes and selects one of the cluster members as the cluster head. The two-tier structure of LEACH divides the network into two layers: 1) cluster members, which collect raw data from the environment and 2) cluster heads, which receive the collected data from cluster-members, and process, aggregate and transmit them to the sink. LEACH reduces the energy consumption of nodes since the most energy-consuming task, which is the long-distance transmission to the sink takes place only in cluster heads. However, LEACH selects the cluster heads randomly using a probabilistic calculation. As a result, the selected cluster heads may not be that strong to handle the high workload of a cluster head; their energy will be depleted very soon, and this reduces the network lifetime if the network desires to keep the throughput reasonably high. To overcome this tradeoff, in this thesis, we propose EALEACH (Energy Aware LEACH), a new clustering combined MAC and routing protocol, which selects cluster heads using their residual energies. This method provides an appropriate selection of cluster heads that are strong enough to handle the expected workload of cluster heads to reach high throughput. Also, our proposed protocol transmits data packets to the sink through intermediate cluster heads, which incredibly reduces the energy consumption on those cluster heads that are far from the sink and keeps them alive for a longer time. We validated the effectiveness and efficiency of our protocol through simulations. The analysis of our results shows that the cluster heads selected by the proposed protocol prolong the network lifetime by 60% in comparison to those selected by LEACH while the approached throughput remains high.

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