Multicasting Sustained CBR and VBR Traffic in Wireless Ad-Hoc Networks

Wireless ad-hoc networks consist of mobile nodes forming a dynamically changing topology without any infrastructure. Multicasting in a wireless ad-hoc network is difficult and challenging. In this paper we propose a novel protocol, Wireless Ad-hoc Real-Time Multicasting (WARM), for multicasting real-time (CBR and VBR) data among nodes in a wireless ad-hoc network. The protocol is distributed, highly adaptive and flexible. Multicast affiliation is receiver initiated. The messaging is localized to the neighborhood of the receiving multicast member and thus the overhead consumed is low. The protocol enables spatial bandwidth reuse along a multicast mesh (a connected structure of multicast group members). The realtime connection is guaranteed quality of service (QoS) in terms of bandwidth. For VBR traffic, the trade-off between reserved and random-access bandwidth for a specific packet loss rate is studied. The protocol is selfhealing in the sense that the mesh structure has the ability to repair itself when members either move or relays fail. We present simulation results to demonstrate features of the protocol and show that the throughput is above 90% for pedestrian environments.