Geographic multicast and multiratecast for wireless sensor and actuator networks

We introduce fully localized protocols Geographic multicast routing (GMR) and Multiratecast routing (MRC) for wireless sensor networks. Geographic multicast routing (GMR) efficiently delivers multicast messages to multiple destinations. Each forwarding node selects a subset of its neighbours as relay nodes towards destinations. GMR optimizes the cost over progress ratio where the cost is equal to the number of relaying neighbours and the progress is the overall reduction of the remaining distances to destinations. GMR's cost-aware greedy neighbour selection achieves a good tradeoff between the bandwidth of the multicast tree and the effectiveness of the data distribution. It also achieves O(Dn min(D, n) 3) computation time, where n is the number of neighbours of current node and D is the number of destinations. Simulation results show that GMR outperforms position based multicast in terms of cost of the trees and computation time over a variety of networking scenarios. Multiratecast routing protocols (MRC) are first fully localized multicast algorithms to solve the multiratecast problem in wireless sensor networks, where source node sends reports to a fixed number of sink nodes at different frequencies (rates). We propose two multiratecast algorithms. The first is Rate Cost Multicast routing (RCM) that applies destination set partition, and calculates best relay neighbour sets with minimum rate cost. Three different rate cost calculation methods are studied to get the best choice of the overall rate cost metrics. The second is Maximum Rate Multicast (MRM) protocol that simplifies the forwarding decision. It selects next forwarding neighbour that provides maximum progress for destinations with the highest rate. Simulation results show that RCM provides best performance in network with small destination number while MRM has comparable performance for network with large number of destinations. As in traditional geographic routing algorithms, deliveries to all destinations in both GMR and MRC are guaranteed by applying face routing when necessary.