Research On Mobile Station Association Technology In Wireless Heterogeneous EH Cellular Network

Heterogeneous cellular networks have become a hot spot in wireless communication research.Compared with the traditional cellular network,the heterogeneous cellular network can not only increase the radio resources,but also increase the system capacity by densely deploying small base stations,and can also transfer part of the services of the macro base station to the small base stations,thereby alleviating the traffic load of the macro base station.The fairness between the base stations is guaranteed.Since the mobile station association method in the traditional cellular network considers how to associate with the macro base station,in the environment facing the heterogeneous cellular network,the previous association method is no longer suitable.Therefore,this paper has done some research on heterogeneous cellular network model and mobile station association method as follows:In wireless energy harvesting(EH)heterogeneous cellular networks,we have established a heterogeneous network model consisting of a macro base station,several small base stations,several relay stations,and a few mobile stations in the flat Rayleigh fading environments.All of stations are only powered by the energy harvested in the surrounding wireless environments.Based on this model,a novel mobile association algorithm based on the weighted signal-to-noise ratio decision(abbreviated as WSNR-MA),is proposed.In WSNR-MA algorithm,the mobile station can not only associate the macro base station and small base stations through the direct communication links,but also can associate the macro base station through the relay links.The association decision depends on both the channel state information and the weighted signal-to-noise ratio threshold defined by the product of a weight function and a signal-to-noise ratio threshold.Expressions of the outage probability of system and average channel capacity have been derived in succession.The simulation results show that the WSNR-MA algorithm is flexible in balancing the traffic load among multiple types of stations,and can achieve a larger system channel capacity and better outage performance than the existing methods,which has positive significance.(2)EH stations with good channel conditions in heterogeneous cellular networks may be frequently associated,resulting in rapid consumption of energy by frequently associated stations,greatly affecting the life cycle of the site or even the system.So,a mobile station association method that takes into account channel state information,station residual energy,and base station load balance.This method not only considers the load balance factor but also considers the impact of EH stations energy consumption while selecting the station with the best channel quality.The simulation results show that compared with the existing mobile station association method,this method can effectively improve the energy efficiency of the EH site while ensuring the channel quality,which is beneficial to the life cycle of the system.