Length-Constrained and Connected Tours for Sensor Networks

We consider a variant of the data gathering problem in sensor networks using multiple mobile elements, where each sensor must be visited with a given minimum frequency. We will construct solutions to this problem where the network is partitioned to possibly several regions, so that a single mobile element visits every node within each region. Therefore we need to partition the network and construct mobile element paths (or tours in our case) that are not too long, so that every sensor can be visited with the required frequency. Assuming the mobile elements move with some average speed, a periodic constraint for visiting a node, translates to a tour length constraint for the mobile element that visits this node. We construct solutions to this problem based on connected tour covers. We propose a divide-and-conquer heuristic to design connected tour covers for this problem and evaluate the performance using several experiments.