Energy- Aware QoS Based Routing Protocols for Heterogeneous WSNs: A Survey

WSNs (Wireless Sensor Networks) are a huge collection of sensor nodes which have limited battery power and limited computational capacity. The power limitation causes the nodes to premature dead so the node power should be used efficiently to prolong the network lifetime. In time critical applications, the data should reach the destination within a deadline and without any packet loss which means the QoS metrics such as reliability and delay are very essential for delivering the data to destination. One of the vital challenges for research in wireless sensor networks is the implementation of routing protocols which achieve both Quality of Service (QoS) and energy efficiency. The main task of the routing protocol is to discover and maintain the routes to transmit the data over the network. At present, to increase the performance of the networks, to achieve load balancing and to provide fault tolerance multipath routing techniques are widely used rather than single path routing technique. We present a review on the existing routing protocols for WSN by considering energy efficiency and QoS. We focus on the main motivation behind the development of each protocol and explain the function of various protocols in detail. We compare the protocols based on energy efficiency and QoS metrics. Finally we conclude the study by giving future research directions