Connectivity in Wireless Sensor Networks in the SINR Model

In this paper, we study the Minimum Channel Assignment (MCA) problem for strong connectivity in wireless sensor networks in the physical model known as Signal-to-Interference-Noise-Ratio (SINR). The main issue is to compute a minimum channel assignment that yields a strongly-connected communication graph spanning all nodes such that the nodes assigned to the same channel can communicate without interference in the SINR model. The complexity measure is the number of channels, and our objective is to minimize it. We show the NP-hardness of the MCA problem, and propose an algorithm that compute a channel assignment for 2-dimensional grid networks. The algorithm produces an assignment with a constant number of channels for the network. We also propose two constant-factor approximation algorithms that yield channel assignments in which the number of channels is bounded by O(Δ), where Δ is the maximum node degree of a network. We also study the performance of the algorithms through simulation.