Message Transmission Scheduling for Multi-hop Wireless Sensor Network with T-Shaped Topology

In multihop wireless sensor networks, packets are periodically generated at each node in every cycle period time and forwarded along lossy wireless links between adjacent nodes toward one of the gateways through which the packets can reach a central data collection server. To cope with frequent packet losses, we consider a TDMA-based packet scheduling with redundant transmissions. In our previous work, we propose an optimal scheduling for the tandemly-arranged network topology with two gateways at the both edges of the network; which is not always realistic. Therefore, in this paper, we extend the research to the T-shaped network topology with three gateways. We derive a static time-slot allocation for T-shaped topology, which maximizes the theoretical probability that all packets are successfully delivered to the server with the basic redundant transmission scheme in a limited cycle period; and show its benefit through numerical results. This extension significantly increases the applicability of our optimal scheduling scheme.