Study On Energy Harvesting Communications For Massive MIMO Enabled Cellular Network

The pursuit of higher transmission capacity has always been the driving force of mobile communication network.Recently,massive multiple-input multiple-output(massive-MIMO)is shown to improve spectrum efficiency,reduce transmission power and user interference without increasing the consumption of spectrum resource.Massive MIMO has become a key technology in 5G mobile communications,and has attracted great attentions from both academia and industry.Meanwhile,simultaneous wireless information and energy transfers(SWIPT)is able to transmit information and user's power at the same time,which is a solution to mitigate the problem in passive user's work in the communication scene.Accordingly,this dissertation studies the joint optimization schemes of resource allocation in multi-user and multi-cell scene using massive MIMO beam-forming and SWIPT.The main innovations of this dissertation are summarized as follows:(1)A power allocation scheme for massive MIMO cellular system is proposed under multi-user time division duplexing(TDD)communication protocol.The BS use maximum ratio transmit(MRT)scheme to transmit signal the downlink.The proposed scheme constructs the optimization model with the aim of minimizing the transmit power at the BS while guaranteeing the quality-of-service(QoS)and energy harvesting requirement in the downlink.Lower bound of signal to interference plus noise ratio(SINR)is derived by using Jensen's inequality.Then,Wishart matrix in Random matrix theory is utilized to simplify SINR at the user side.Simulation results show the proposed scheme save a large amount of power compared to equal power allocation.(2)Resource allocation schemes based on the minimization of the total base station(BS)transmit power is proposed for SWIPT multi-cell massive MIMO system under harvest-then-transmit protocol.With the constraint on the minimal quality-of-service(QoS)requirement,these original non-convex problems are transformed into their solvable ones which can be solved iteratively by successive convex approximation.Simulation results show that the iterative successive convex approximation algorithm converges quickly,and by exploiting the diversity effect of large-scale antenna array,the recourse allocation scheme can achieve similar power efficiency compared with the non-asymptotic scheme.