Routing Using Mobile Gateways in Low-Power and Lossy Networks for Disaster Scenarios

摘要

Typically, a temporary communication infrastructure deployed in a disaster scenario lacks the ability to locate those people who do not have an access to a communication device. Moreover, the system cannot detect emergency situations that may arise as an aftermath of a disaster, such as a fire or building collapse. Hence, a supporting network is also required that can detect different events and report them to a gateway. A wireless sensor network can be used as the supporting network as sensor node can detect a number of events and communicate them as well. Usually, a disaster affected area is large, hence nodes form a multi-hop network to reach the gateway. Usually, in a disaster scenario gateways are mobile, therefore in this paper we present different routing protocols that can be used in a disaster scenario with mobile gateways. Our protocols use multiple routing metrics to discover data forwarding paths to the gateways. Moreover, the protocols use the routing metrics in greedy and end-to-end basis. We performed extensive simulations to evaluate the protocols. We analysed the impact of the number of gateways, radio duty-cycling, and different network topologies on the protocols' performance. Our results demonstrate the following: (i) grid network topology demonstrates better performance, (ii) under random topologies along with duty cycling operation the shortest hop-count routing metric demonstrates better performance, (iii) expected transmission count (ETX) should be used in a greedy manner in conjunction with the shortest hop-count metric under random topologies with no duty cycling, (iv) in gird topology where nodes are using radio duty-cycling ETX should be used in greedy manner along with the shortest hop-count metric, and (v) network performance improve as we increase the number of gateways in the network.