The Research On Energy Optimization In Wireless Sensor Networks

Wireless sensor networks(WSN for short) usually composed of a large amount of sensors that deployed in the monitoring fields to sense the physical environments, and a few sinks that involved in gathering data and communicating with the outside. Because of the data-centric application that mentioned above, routing protocol has become the most important part of the design in WSN. There are many routing protocols designed for WSN being proposed already. But if the sink is static, the sensors that around the sink (called "hotspots") will deplete their energy so fast to death. Many researches have pointed out that sink mobility can reduce the affection of the "hotspots" problem, and increase the lifetime of WSN remarkably.First of all, summarizations of routing protocols and sink moving strategies have been proposed, and comparisons between different protocols and moving strategies have been made. Then a LMREM(Local Maximum Residual Energy Movement) strategy was proposed, which suggested that sink periodically move to a new position with the highest stay value that together defined by average neighbor residual energy and the neighbor number.Combined with LMREM and based on Minimum Cost Forwarding (MCF) protocol, a MMCF routing protocol that fully support large scale sensor network application have been introduced. By extinguishing the data redundancy, taking advantage of the energy-rich nodes as the next hop, reaching sink in a multi-path way and taking sink mobility into consideration, MMCF would balance the network load greatly and achieve a prominent increase in network lifetime. At last, a simulation is carried out by NS2. The simulation results show that in contrast with MCF, LMREM-MMCF can prolong the lifetime of the network remarkably, while having a good performance in packet drop rate and average data delay.