Research On Capacity Of Energy Harvesting Channel For WSN With Hybrid Energy Storage

With the rapid development and wide application of wireless sensor networks,the energy-constrained problem of sensor nodes as the main challenge needs to be solved urgently both in academia and industry.Energy harvesting technology has been envisioned as one promising solution to solve this problem for its flexible deployment and sustainable energy supply.So the wireless sensor networks based on energy harvesting has been widely taken into consideration by scholars.In order to prolong the life of the entire network,sensor nodes with energy harvesting capability can harvest energy from the surrounding environment to recharge their battery.However,for wireless sensor networks with energy harvesting,it is important to investigate the effects of randomness of energy harvesting for message transmission,as well as efficiency of harvesting energy utilization.This thesis studies the capacity of the energy harvesting channel for WSN,the main contributions are listed as follows:1.Due to the limitation of single battery energy storage in traditional wireless sensor networks and the instability of energy source in existing energy harvesting technology,a hybrid energy storage structure model composed by super capacitor and battery is introduced for nodes,and the corresponding point-to-point energy harvesting channel model is presented.By considering the intermittent peculiarities of energy harvesting,an approximately optimal energy allocation strategy(AOEA)is proposed,by which the upper and lower bounds of the average throughput are deduced,In particular,the gap of two bounds is derived to be a constant,and the channel capacity is further obtained.Within the numerical analysis,the effect of harvesting energy,storage capacity and battery storage efficiency to the channel capacity are analyzed respectively.While the experiment shows that compared with the conventional wireless node with single battery storage,the hybrid energy storage structure can improve the energy utilization and increase the channel capacity.2.Based on the study of the point-to-point energy harvesting channel,the capacity of multi-access energy harvesting channel is analyzed.Firstly,the multi-access energy harvesting communication channel model is presented,in which nodes use the hybrid energy storage.Then assuming the mean harvesting energy of every node is equal,the upper and lower bounds of the average throughput is deduced by adoption of AOEA strategy for different harvest energy cases,and the channel capacity is further obtained.Within the numerical analysis,the effect of harvesting energy,storage capacity and the number of nodes to the channel capacity are analyzed respectively.While the experiment result shows that the hybrid energy storage structure can increase the channel capacity on the basis of single battery storage.