Transmission of Real-time Traffic in TDMA Multi-hop Wireless Ad-hoc Networks

In this paper we present a method for routing and scheduling real-time traffic in TDMA multi-hop wireless ad-hoc network in the presence of noise. We state the capacity optimization problem that is to maximize the number of simultaneously transmitted real-time voice flows with satisfactory end-to-end packet delivery probability and delay. As the considered problem is NP-complete we decompose it into two parts. First is to provide QoS for the flow transmitted via given route using minimum number of channel resources. Second is to design routing metric which maximizes the network capacity when the proposed method for QoS provision is used. First problem is solved by reserving several slots in the TDMA frame for re-transmitting the voice packet and by allowing nodes to reserve slots only in the predefined part of the frame. We provide the constraints for this QoS provision method and propose a simple heuristic that meets all the constraints. Regarding routing metric, we propose logarithmic metric and its topology-aware extension and perform the simulation for evaluating the efficiency of these metrics and comparing them with existing ones.