Research On Resource Allocation In GFDM Based Simultaneous Wireless Information And Power Transfer

The Fifth Generation(5G)mobile communication places higher demands on information rate,battery life,spectral efficiency and quality 'of user experience.The high energy consumption leads to unprecedented attention to green and sustainable communications.As an emerging technique,Simultaneous Wireless Information and Power Transfer(SWIPT)provides a technical paradigm to support information and energy transmission for mobile terminals by using harvested radio-frequency energy.Current researches on multi-carrier SWIPT communication is mainly directed to Orthogonal Frequency Division Multiplexing(OFDM).However,strict subcarrier orthogonality,long cyclic prefix and high out-of-band radiation make OFDM incompetent in 5G application scenarios.As an evolution of OFDM,Generalized Frequency Division Multiplexing(GFDM)breaks the subcarrier orthogonality,supports higher spectral efficiency and more flexible resource allocation.There is little literature on the combination of SWIPT with GFDM.Therefore,the resource allocation in GFDM based SWIPT communication is investigated in this thesis.Firstly,the related techniques and theories of multi-carrier SWIPT communication are introduced.For multi-carrier transmission technology,the basic principles of OFDM and GFDM are learnt,the structure of GFDM two-dimensional time-frequency data block is analyzed.For SWIPT technique,two typical modes are introduced.For cooperative relay transmission technology,typical relay systems,transmission modes and forwarding modes are studied.In order to solve the optimization problem of resource allocation,the concepts of convex optimization and the solution methods for optimization problems are introduced.Then,considering the low spectrum efficiency and the inflexible resource allocation of OFDM,a SWIPT-based resource allocation scheme in multi-user downlink GFDM system is proposed.In this scheme,the power splitter divides received power into two parts,which are used to transmit information and harvest energy,respectively.Under the premise of ensuring the minimum harvested energy of each user,the total downlink information rate is maximized by jointly optimizing sub-block allocation,sub-block power and power splitting ratio.In order to solve the above optimization problem,a corresponding iterative algorithm is proposed.The simulation results show that the proposed algorithm can effectively solve the optimization problem.At the same time,compared with OFDM,the GFDM based scheme can flexibly allocate resource and achieve a higher information rate.Finally,considering the poor channel condition of cell-edge user,a SWIPT-based resource allocation scheme in GFDM cooperative relay system is proposed.In this scheme,the sub-block set of the relay node is divided into two parts,one for information transmission and the other for energy harvesting.Under the constraints of relay total transmit power,harvested energy at cell-edge user and total transmission slot,the information rate of cell-edge user is maximized by jointly optimizing sub-block allocation,sub-block power and sub-slot allocation.In order to solve the above optimization problem,a corresponding iterative algorithm is proposed.The simulation results show that the proposed algorithm can effectively solve the optimization problem.At the sane time,compared with OFDM,the GFDM based scheme can flexibly allocate resource and achieve higher information rate.