A Low-Latency TDMA Scheduler for Multi-hop Cluster Based MANETs with Directional Antennas

For Mobile Ad Hoc Network (MANET) applications which involve large propagation delays and/or directional antennas, a Time Division Multiple Access (TDMA) Medium Access Control (MAC) is a resource- and bandwidth-efficient solution. Meanwhile, clustering is a solution to the scalability and high mobility which is commonly required by MANETs. Here we develop a system which combines a TDMA MAC using directional antennas with the Multi-Meshed Tree (MMT) algorithm, which handles clustering and routing tasks. Some of the benefits of this combination include being able to synchronously schedule all intra-cluster routes as they are formed, being able to optimize the intra-cluster schedules for low latency, and being able to calculate these schedules with knowledge of only the intra-cluster topology, which is already maintained by MMT. We first analytically determine the end-to-end latency under various cases, and then confirm these results for several cases through OPNET simulation. Additionally, we note the high degree of slot re-use which is possible due to the use of directional antennas, which is demonstrated by the simulation results.