Survey on Routing Protocols in Wireless Sensor Networks

Wireless sensor networks are formed by small sensor nodes communicating over wireless links without using a fixed network infrastructure. Sensor nodes have a limited transmission range, and their processing and storage capabilities as well as their energy resources are also limited. Routing protocols for wireless sensor networks have to ensure reliable multi-hop communication under these conditions. The nodes can be densely deployed in close proximity to the phenomenon to be observed. They can be deployed in hostile environments where the nodes may not be physically accessible and are subject to tampering. Nodes can be added to and deleted from the network at any time, resulting in unpredictable changes to the topology of the network. This presents new challenges in the design of routing protocols for sensor networks. In this paper, the constituent building blocks of sensor network routing protocols are identified and analyzed. The routing protocols are broadly classified into three categories: flat, hierarchical and Location aware Routing and further into subcategories based on the centrality of their theme. Several routing algorithms belonging to each category that have been proposed in the literature are explored.