Recently, the research area interest towards the development of wireless sensor network (WSN) has increased. However, WSNs have one of significant issues as improving an energy-efficient routing protocol. A WSN has a crucial problem of energy consumption that effects the network lifetime as sensor nodes have a limitation of power. To overcome these limitations, it’s required to improve energy-efficient communication protocols for WSNs. Different types of techniques have considered by various research communities for providing energy-efficient solutions for WSNs. The energy consumption reduces using the clustering as an efficient data collection method and the collected data forward to a cluster-head which belong to the nodes in clustered networks. The information transmits to BS (base station) either in an uncompressed or compressed manner after collecting all data by a cluster-head from all member nodes. Based on other cluster-heads, the data transmit in a multi-hop network. Due to the heavy inter-cluster relay, earlier death happens to the cluster-heads (CHs) that locates very closely to the sink. Therefore, a fuzzy optimal CH selection algorithm has proposed to select the optimal CHs to improve the lifetime. Based on different parameters like cluster load, communication cost, neighbour density, node degree, inter and intra cluster distance, and node energy, the proposed algorithm of CH selection chooses the CHs. To determine an optimal route for transmitting the data from CH to sink, the modified Emperor Penguin Optimization (EPO) uses after selecting the CH. The proposed technique implements and compares with other earlier methods in terms of packet delivery ratio, lifetime, energy consumption, end to end delay and throughput. The proposed approach shows best performance than the other methods based on the simulation results.

Most of the wireless sensor networks are energy limited. To improve the lifetime of a network, the energy consumption should be reduced. Clustering is a proven technique that reduces energy consumption in WSNs. The energy can be saved by sending the collected information to the sink using the Cluster Head (CH) nodes. Fault tolerance is a crucial issue in WSNs, and one cluster head failure collapses the entire data communication. This paper presents a fault tolerance cluster-based routing technique. This paper aims to provide improved fault tolerance and data aggregation technique for clustered WSN using FTOR-ModPSO (Fault tolerance and optimal relay node with modified Particle Swarm Optimization). Here, the fault tolerance is achieved by selecting the backup cluster head (BKCH) for every cluster. The method consists of two phases. The network is categorized into clusters in the first phase whereas in the second phase, CHs and BKCHs are selected. Intra-cluster communication happens between member and CH nodes. Aggregator nodes (AG) are used for inter-cluster communication, and modified PSO identifies CH and AG's best relay. The fault tolerance and packet delivery rate are increased with less energy utilization compared to other existing energy-saving protocols by implementing this method.