Hybrid LEACH: A relay node based low energy adaptive clustering hierarchy for wireless sensor networks

Prolonging the lifetime of a sensor node powered by battery in both homogeneous and heterogeneous wireless sensor networks is a massive challenging area of research now-a-days. To achieve this target many research works including low energy adaptive clustering hierarchy (LEACH) and its variants use clustering techniques to reduce energy spent by keeping most of the nodes in sleeping mode whenever possible. LEACH cannot solve the problem of extending the networks life time due to loosing huge energy of sensor nodes selected as cluster heads for communications. To save energy of cluster heads, relay node based schemes use independent relay nodes as cluster heads. These schemes, however, still suffer from the problems of relay node placement, blind spots and immature death of cluster heads. Addressing the above mentioned problems, this paper proposes a new robust relay node based hybrid LEACH which incorporates the recently developed energy comparison LEACH within the relay nodes based technique so that the network still operates, in absence of relay nodes, as long as even a single node having energy to communicate. The proposed scheme also maintains the efficiency of energy utilization through controlling the size of cluster in a distributed manner for the first time. Simulation results prove the superiority of the proposed scheme over the relay node based scheme with an improvement of 6%-30% extra network lifetime and significant reduction of packet loss during communications.