Optimized sink mobility for energy and delay efficient data collection in FWSNs

Network fragmentation is a potential problem in wireless sensor networks (WSNs) due to many reasons like, node failures or environmental conditions (obstacles) that prevent connected deployments. One approach to cope with this problem is to have a mobile sink node (MS) patrol the network field and collect the data from all the fragments across the network. In this paper, we use a dynamic programming (DP) approach to determine the mobility trajectory of the MS within each fragment such that the energy consumption at the sensor nodes within the fragment is minimized. Moreover, we study the problem of finding the shortest route (cycle) that the MS should take in its journey between fragments in order to reduce a fragment´s inter-visit time. For this purpose, we propose an Integer Linear Programming (ILP) formulation to find the optimal route. As finding the optimal route is NP-hard, we also propose a heuristic approach to find a near optimal solution.