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The resource-constrained nature of wireless sensor networks engenders the development of energy-efficient network operations. To mitigate the prime concern of developing an energy-efficient network, clustering of the nodes has emerged as a very effective tool. If executed intelligently, clustering can not only help in obtaining even load distribution among the network nodes but also help in having the enhanced network lifetime and scalability. In this work, a Metaheuristic Load-Balancing-Based Clustering Technique (MLBCT) in wireless sensor networks has been proposed which formulates the energy-balanced clusters based on the differential evolution technique to improve the network lifetime. To ensure the formation of balanced clusters, several metrics like nodes’ proximity, nodes’ distribution, and energy distribution across the sensing field have been considered. Moreover, to facilitate the even load distribution among the cluster members, a randomized rotation of cluster head is implemented. The supremacy of the proposed scheme is confirmed through an extensive set of simulations against the state-of-art schemes. Simulation results reflect an average gain of 51.85% in network lifetime under the variable network configurations in an ideal environment. Moreover, a thorough statistical analysis is performed to prove the efficacy of the proposed fitness function by obtaining confidence intervals under two different network scenarios with variable node counts.

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In this paper, we study the effect of energy loss of charge carriers due to carrier-carrier interactions prior to impact ionization on the static and large-signal characteristics of double-drift region impact avalanche transit time (IMPATT) diodes based on Si designed to operate at millimeter-wave (mm-wave) atmospheric window frequencies such as 94, 140, and 220 GHz. The above mentioned effect has been incorporated in the simulation by taking into account a recently reported generalized analytical model of impact ionization rate of charge carriers based on multistage scattering phenomena in the base semiconductor. Results are compared with static and large-signal signal simulation results of the same diodes that we have reported earlier by taking into account the empirical relation of ionization rates fitted from the experimental data (experiment was carried out on IMPATT structures suitable for operating near 100 GHz). It is observed that both the large-signal RF power output and DC to RF conversion efficiency of the diodes are deteriorated significantly due to reduced ionization rates as a consequence of carrier-carrier collision events prior to the impact ionization. This effect is found to be more pronounced in 140 and B Aritra Acharyya ari_besu@yahoo.co.in 220 GHz diodes due to the enhanced carrier-carrier collisions within those diodes having greater background doping densities as compared to 94 GHz diode. The simulation results presented in this paper found to be in closer agreement with the experimental results as compared to the results that we have reported earlier.