Adaptive Guard Time Control for Distributed TDMA Networks with a Large Propagation Delay

In TDMA networks with a large propagation delay, a large guard time is required to ensure broadcasting without collisions. However, this causes considerable waste, and degrades network performance. In this paper, we propose Adaptive Guard Time with Inter-transmitter Propagation Delay (AGT-IPD) to reduce the guard time while ensuring broadcasting. Each transmitter adjusts the guard time by using the propagation delay for the next time slot owner. AGT-IPD employs a distributed mechanism for propagation delay estimation and time synchronization. We then conduct a trade-off analysis, and demonstrate efficient guard time management and overhead control from AGT-IPD from simulation modeling. Through numerical results, AGT-IPD shows improvements that provide higher link utilization than other schemes to which it is compared, regardless of packet length, maximum communication range, the number of nodes, and the number of errors.