Routing Using Mobile Gateways in Low-Power and Lossy Networks for Disaster Scenarios
Muhammad Omer Farooq
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 multihop 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.
Keywords: Low-power and lossy network (LLN), routing in disaster scenario, multi-gateway LLN, mobile gateways