Unslotted transmission schedules for practical underwater acoustic multihop grid networks with large propagation delays

In a recent work, a regular grid-based network topology with multihop relaying was investigated. A transmission strategy which maximizes the throughput while exploiting the large propagation delay was presented, and the upper bound on throughput established. However, deployments of communication nodes in the ocean inevitably result in slight positional deviations from the expected locations of the nodes, a departure from the perfectly aligned regular grid networks assumed. The irregularity in the grid network due to deployment errors degrades the network throughput significantly. We consider this practical problem and propose an algorithm to compute unslotted transmission schedules. We formulate the scheduling problem as a Mixed-Integer Linear Problem (MILP) and compute throughput-maximizing schedules. We demonstrate the throughput gain compared to the existing state of the art techniques and verify the solution in the simulator for various random instances of the grid network deployment.