Association Schemes in a Wireless Sensor Network with a Cluster Tree Topology

In a wireless sensor network (WSN) with specially deployed cluster heads (CHs), association relation between sensor nodes and the CHs is important as it affects the radio resource allocations, which further determine the overall network throughput, energy consumption, and other performance. In a lot of cases, the CHs are placed in random locations, and strong overlapping may exist between their coverage areas so that sensor nodes can choose to associate to different CHs. In this paper we first formulate two optimization problems that jointly consider sensor node association and radio resource allocations, one for maximizing the network level throughput, and another for balancing the energy consumption among the CHs. For each of the optimization problems, a heuristic scheme is designed that jointly considers both the timeline allocations of the CHs and the sensor node association. Numerical results based on computer simulation demonstrate that the proposed schemes achieve close-to-optimum performance. In addition, the schemes achieve much better throughput and energy performance than the straightforward association schemes.