Impact of limiting hop count on lifetime of wireless sensor networks

Wireless Sensor Networks (WSNs) sense various events in their deployment area and collect data to one center.WSN can be used for protecting water resource and forests, military applications, medical applications, prediction of natural events, tracking animals in nature. A WSN consist of multiple sensor nodes and one or more base stations which gather data from nodes. Sensor nodes uses their internal batteries for energy. Due to the difficulties of the conditions of deployment area, most of time it is not possible to change the batteries of the nodes. Therefore, when the batteries is depleted, lifetime of nodes will be finished. Nodes should use their battery energy efficiency to prolong to lifetime of network. Nodes reach their generated data to base station with single hop or multi hop by using other nodes as a relay. Nodes consume a large part of the energy for wireless communication, so they send data to near nodes to communicate base station to spend their energy more efficiently. Total hop count of network will be increase in this case. When lifetime of network increases on the other hand total hop count will be reach higher numbers. Increasing of hop count effect negatively other parameters such as congestion, delay, complexity, data security, interference, robustness in networks. In this study, we aimed to maximize lifetime in network with maximum hop count limit. Firstly, we tried to maximize lifetime with different hop count limits from minimum hop count. Secondly, we tried to minimize total hop count when network lifetime limited with a lower bound. We modelled all network as a mathematical optimization problem and we used different MIP (Mixed-Integer Programming) frameworks to solve these optimization problems. According to the results, we suggest optimum points for trade of between lifetime and total hop count.