Real-time multicast for wireless multihop networks

Wireless multicast for multihop ad-hoc networks ensures that the same information is delivered efficiently to multiple recipients simultaneously. However, existing protocols ignore the real-time nature of many wireless applications such as real-time video and audio communications in mesh and ad-hoc networks. Further, devices in such networks are typically energy-constrained, i.e., multicast protocols have to trade off timeliness with energy efficiency. This paper presents RTMC, a real-time multicast protocol for wireless multihop networks that allows receivers to specify their individual real-time constraints and establishes multicast trees such that receivers’ deadlines are met and overall energy consumption in the network is reduced. Toward this end, RTMC relies on dynamically prioritized packet scheduling on forwarding nodes, prioritized channel access at the MAC layer, feedback control for latency management, tree adaptations to address mobility, dynamic subscriptions and unsubscriptions, and adaptations to address link breakages. Simulation results show that, compared to non-real-time multicast techniques, RTMC can provide user-specific latency management while reducing the energy consumption in the network.