High transmission power increases the capacity of ad hoc wireless networks

Abstract

In this paper, the effect of transmission power on the throughput capacity of finite ad hoc wireless networks, considering a scheduling-based medium access control (MAC) protocol such as time division multiple access (TDMA) and an interference model that is based on the received signal-to-interference-plus-noise ratio (SINR) levels, is analyzed and investigated. The authors prove that independent of nodal distribution and traffic pattern, the capacity of an ad hoc wireless network is maximized by properly increasing the nodal transmission power. Under the special case of their analysis that the maximum transmission power can be arbitrarily large, the authors prove that the fully connected topology (i.e., the topology under which every node can directly communicate with every other node in the network) is always an optimum topology, independent of nodal distribution and traffic pattern. The present result stands in sharp contrast with previous results that appeared in the literature for networks with random nodal distribution and traffic pattern, which suggest that the use of minimal common transmission power that maintains connectivity in the network maximizes the throughput capacity. A linear programming (LP) formulation for obtaining the exact solution to the optimization problem, which yields the throughput capacity of finite ad hoc wireless networks given a nodal transmit power vector, is also derived. The authors' LP-based performance evaluation results confirm the distinct capacity improvement that can be attained under their recommended approach, as well as identify the magnitude of capacity upgrade that can be realized for networks with random and uniform topologies and traffic patterns.