Optimal Cluster Head Selection in the LEACH Architecture

LEACH (low energy adaptive clustering hierarchy) (W. Heinzelman et al., 2000) is one of the popular cluster-based structures, which has been widely proposed in wireless sensor networks. LEACH uses a TDMA based MAC protocol, and in order to maintain a balanced energy consumption, suggests that each node probabilistically become a cluster head. To reduce the energy consumption and to avoid the strict synchronization requirements of TDMA, we first apply a sleep-wakeup based decentralized MAC protocol to LEACH, then we present an analytic framework for obtaining the optimal probability with which a node becomes a cluster head in order to minimize the network´s energy consumption. The analysis is first presented for small networks, under the assumption of identical expected distance of all cluster heads from the sink. Then the analysis is extended for large networks to consider the case when the distances of various sections of the network from the sink may be different, since nodes further away have to spend greater energy in order to reach the sink. Our simulation results show that using this optimal probability results in much more efficient energy consumption and compared with the current LEACH, our proposal consumes significantly less power.