An enhanced location-free Greedy Forward algorithm with hole bypass capability in wireless sensor networks
Greedy Forward is a technique for data routing in Wireless Sensor Networks (WSNs) in which data packets are forwarded to the node that is geographically closer to the destination node. Two main concerns can be found in routing algorithms based on this technique: first, it requires all sensor nodes to know their physical location. Second, this kind of algorithm does not work in cases when a node is located in a network 'hole', i.e., the node does not have any neighbor closer to the destination node. In this work, we propose a new Greedy Forward algorithm that can be used in routing protocols for WSNs that does not require localization of the nodes and also is able to deal with nodes located near network holes. Differently from current greedy forward algorithms, our approach uses only the Received Signal Strength Indicator (RSSI) of exchanged packets. Based on this observation, we propose the RSSR (Received Signal Strength Routing) algorithm with two variants: RSSR Election and RSSR Selection. In the RSSR Election, the next hop is dynamically elected and no packets are required for the routing task. In the RSSR Selection, neighbors exchange packets with RSSI information and the next hop of the packet is then selected from a routing table. Then, we present a novel technique for dealing with network holes even when the physical location of the nodes is unknown. This technique improves the reliability and applicability of the proposed schemes in most WSN scenarios. Our results indicate clearly that the proposed algorithms have all the benefits of a greedy forward algorithm but with better performance, better packet delivery rate and without requiring position information. We propose a new Greedy Forward algorithm for routing protocols in WSNs.It does not require localization information, but only the RSSI of the packets.It is also able to deal with nodes located near network holes.