Topology reconfiguration of FSO/RF directional wireless networks with successive approximations

Abstract

Recent developments in pointing, acquisition, and tracking have enabled the formation of point-to-point FSO or narrow beam directional wireless networks that are capable of dynamic changes in their topology. Autonomous changes to topology in response to varying available link capacities and load demands of various nodes is called topology control. Topology control consists of computing new topologies to dynamically optimize the network under changing traffic conditions, and then carrying out the reconfiguration process to achieve the target topology. Our current work in this area studies the process of topology reconfiguration by using the packet drops that happen during this process as a cost metric. It is shown that the reconfiguration cost can be minimized when the target topology is reached by implementing the topology reconfiguration as a series of smaller steps (successive approximations). It is also shown that a topology computation algorithm that results in lower overall packet drops can be obtained by including the reconfiguration cost in the objective function along with the typical objective of congestion minimization. Simulations are used to evaluate and compare the performance of topology computation heuristics when the objective function includes reconfiguration cost.