Improving simplified multicast forwarding using an elevated relay node

In emergency and crisis operations, group communication is essential to coordinate rescue efforts. Mobile Ad Hoc Networks (MANETs) can provide dynamic and resilient communication services in areas without a working communication infrastructure. The connectivity of MANETs can be improved using an elevated network node due to larger ground coverage, thus improving node reachability. Simplified Multicast Forwarding (SMF) is a scheme to efficiently distribute group communication packets in MANETs. In this paper, we explore methods to utilize SMF in a MANET supported by an elevated network node. We show that an elevated network node can improve the packet delivery ratio in a MANET with SMF-distribution of multicast packets. Further gains are made by unicasting the packets from the source to the elevated network node, moving the initial point of the SMF-distribution to the elevated network node. The consequences of a potential unicast packet loss are lessened by the source retransmitting the packet as multicast if it fails to receive the SMF-forwarded packet from the elevated network node. We achieve a high packet delivery ratio while maintaining a low cost for most topology sizes. Finally, the paper outlines future research directions for group communication in MANETs.