Reliable, distributed and energy-efficient broadcasting in multi-hop mobile ad hoc networks

Real-time, mission-critical applications in mobile ad hoc networks, e.g., wireless sensor networks, have been seen for military battlefield operations, emergency relief for terrorist attacks, patient condition-monitoring in medical systems. We study fault-tolerant and distributed network protocols that support reliable, energy-efficient broadcasting for real-time multimedia transmission in multi-hop mobile ad hoc networks. Given a communication network with a set of mobile nodes where strong global network connectivity is guaranteed, provided that each node is within its maximum power, our objective is to find a sub-network that only has the minimum-energy broadcast tree that is rooted from a given sender node and reaches each destination node. Due to the reliable and collaborative environment in the above mission-critical applications, it is also required that not only the sender node can reach each destination node but also each destination node can reach the root node, i.e., the communication is necessarily bidirectional. By constructing the broadcast tree in a distributed and self-reconfiguring fashion, the energy consumption can be distributed among the nodes, the interference among node communications can be mitigated. Moreover, the scheme is resilient to mobility and scales well since each node makes its decision based on its local information only. To support reliable, cooperative broadcast services, several node failure recovery cases have also been discussed.