Two-level distributed clustering routing algorithm based on unequal clusters for large-scale Internet of Things networks

According to the recent advancements in communication technologies and the widespread use of smart devices, our environment can be transforming into the Internet of Things (IoT) because it can connect the physical, cyber, and biological world via smart sensors for different purposes. Wireless sensor networks are considered as one of the main infrastructures in the IoT systems. Therefore, decreasing the total energy consumption of sensor nodes and prolonging the network longevity are two important challenges that should be considered. To increase energy efficiency and to improve the network longevity, a two-level distributed clustering routing algorithm based on unequal clusters has been proposed for large-scale IoT systems. The main idea is to decrease the data transmission distances between member nodes and cluster heads to mitigate the hot spot problem by distributing two cluster heads in each cluster, which in turn leads to energy conservation and load balancing. The clustering method is two level due to the benefits it offers for the sensor nodes. First, each node can transfer its data to the nearest cluster head because a primary cluster head and a secondary cluster head have been considered for each cluster. Therefore, the nodes far from the primary cluster head can be organized based on their distances to the closest cluster head to reduce their data transmission distances to the cluster heads. Second, two cluster heads can be replaced with each other in different circumstances. This reduces the overhead of the cluster head selection algorithm in the proposed scheme. Third, the sensor nodes can benefit from the primary and secondary cluster heads to transfer the data to the sink through different paths with the minimum energy consumption. Simulation results indicate that the proposed algorithm has better performance in terms of total energy consumption, total network energy, and network longevity compared to previous similar schemes.