Joint scheduling and routing using space–time graphs for TDM wireless mesh networks

Abstract

This paper presents a novel algorithm for joint routing and scheduling in TDM wireless mesh networks. We introduce a new construct, called a "space---time graph," which incorporates the spatial and temporal aspects of routing in one structure by replicating a spatial network connectivity graph in layers along the time dimension. The power of the space---time graph lies in the fact that a path from one node to another in it specifies both a physical route in space as well as a schedule in time for a message. Hence the complicated and intractable problem of routing and scheduling reduces to the relatively simpler problem of determining shortest paths in a graph. Through simulations we show that a simply greedy algorithm on the space---time graph outperforms two state-of-the-art methods in terms of time taken to successfully transmit a set of messages from their sources to their destinations.