Data quality maximization in sensor networks with a mobile sink

In this paper we consider a wireless sensor network with a mobile sink moving along a fixed trajectory without stop to collect data. We assume that a few powerful and high-capacity sensors deployed nearby the trajectory are the gateways, which are able to communicate with the sink directly when the sink is within their transmission ranges. Gateways play the role of relay nodes for the other sensors in the network. We also assume that the time of data uploading from the gateways to the mobile sink is limited. Thus, data from only a subset of sensors, called packet nodes, can be collected and used to estimate those of the others. The data quality is measured by the estimation accuracy. The upper bound on the number of packet nodes for a gateway is defined as the gateway quota. We formulate the optimization problem with the objective to identify the set of packet nodes, allocate them to gateways subject to gateway quotas, and devise an energy-efficient routing protocol, such that the sink can efficiently collect data generated from packet nodes with the maximum quality. Due to the NP-hardness of this problem, we propose a heuristic with low computation complexity. We also conduct extensive experiments by simulation to evaluate the performance of the proposed heuristic.