Multi-criteria itinerary planning for the mobile sink in heterogeneous wireless sensor networks

The mobile sink is usually applied to improving the performance of wireless sensor networks (WSNs). This improvement is subject to the itinerary plan, through which the sojourn times and settlement locations are determined. This paper simultaneously considers multiple criteria like data merit, latency, deadline, used memory, and travel time, then presents a multi-objective Integer Quadratically Constrained Quadratic Programming (IQCQP) for planning itinerary of mobile sink in WSNs. In practice, this programming should be solved in a centralized node and it is computationally NP-hard, but the mathematical formulation can help estimate the problem characteristic and figure out the optimal path for the mobile sink. In addition, this paper proposes a multi-attribute algorithm where the sink gathers attributes of possible sites and compares them by applying fuzzy Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). Therefore, the neighboring adjacent sites are ranked by TOPSIS, then the best site is selected and the mobile sink moves there. The proposed algorithm has lower complexity and utilizes local information to make a decision, therefore it is can handle dynamic features of WSNs. The proposed methods are assessed through rigorous simulations, the results reveal that the proposed distributed algorithm outperforms counterparts in terms of performance metrics (total merit, latency, gathered, expired, and lost data) in a heterogeneous WSN.