Optimized multicast based on multipoint relaying

Applications requiring the use of multicast such as military battlefield communication, rescue operations, conferencing, multi-user games, and context-aware applications, are becoming increasingly successful. To ensure broad popularization of these applications, they should be available regardless of time and place. Because wireless mobile ad hoc networks can automatically create a wide wireless network, which can extend an existing wired network, they are an ideal solution to support this concept of multicast, anytime, anywhere. To provide multicast services for mobile ad hoc networks, many protocols have been proposed. Their internal mechanisms are different but all protocols strive to achieve the same goal: efficient and reliable multicast packet delivery. However, there is often a trade-off between reliability and efficiency. Indeed, multicast packet delivery paths tend to become fragile with respect to mobility when they are optimized for bandwidth and become inefficient with respect to bandwidth when designed to be resilient to mobility. To improve the trade-off between efficiency and reliability, we use MPRs (multi point relays), the basic mechanism of OLSR for optimization, OLSR being one the main RFC in IETF Manet WG. Our approach is to build multicast delivery paths using MPRs to transmit multicast packets from multicast source to group members. Extensive simulation results shows that the proposed algorithm improves the reliability of multicasting without degrading noticeably the efficiency.