An approach to topology management in directional networks

Narrow-beam directional antennas can provide enormous gains in data rate, range, power expenditure, and spatial re-use. When ranges extend to hundreds of kilometers, there can be thousands of nodes in communications range. Since directional networks tend to incur an overhead cost per link, some process must select the potential neighbors to which a node actually links and are therefore reported as neighbors to the routing protocol. This process is known as topology management. If the purpose is to reduce the number of links, the key question is what criteria are used to select them. In this paper, we propose a matrix model that allows network managers to define pairwise standards for throughput, delay, and path redundancy. In the context of a time division multiple access system, our proposed objective is to meet the specified standards with the minimum number of links and time slot utilization, in order to meet second-order design objectives. If these standards matrices are periodically (but rarely) distributed, the network can work towards a common set of precisely defined performance objectives. We provide an example of an algorithm that can exploit this information to rapidly and scalably converge on a solution with minimal additional messaging overhead.