Research On Transceiver Designs For Multi-antenna SWIPT Systems

Recently,EH communication systems that can harvest energy from radio-frequency signals have attracted considerable interest since they offer a promising solution to providing cost-effective and perpetual power supply for wireless networks.The unified study of simultaneous wireless in-formation and power transfer(SWIPT)has therefore drawn significant attention lately,as it opens new challenges and possibilities in the analysis and design of transmission schemes and proto-cols.In this thesis,we study joint transceiver designs for various multi-antenna systems with SWIPT,where new communication techniques,such as full-duplex(FD)and cloud radio access network(C-RAN)are involved.The FD transmission is a powerful and promising technique for the next-generation wireless communication systems.Compared with the traditional half-duplex trans-mission,it can better utilize the spectrum by enabling signal transmission and reception over the same transmit opportunity.While,the C-RAN is an emerging network architecture that provides a promising solution to support the ever increasing data traffic,by improving both the spectrum and energy efficiency of current wireless networksFirstly,we consider the multiple-input single-output(MISO)interference channel where the received signal is divided into two parts for information decoding and energy harvesting(EH),respectively.The transmit beamforming vectors and receive power splitting ratios are jointly de-signed in order to minimize the total transmission power subject to both signal-to-interference-plus-noise ratio(SINR)and EH constraints.Most joint beamforming and power splitting(JBPS)designs assume that perfect channel state information(CSI)is available;however CSI errors are inevitable in practice.To overcome this limitation,we study the robust JBPS design problem as-suming a norm-bounded error(NBE)model for the CSI.Three different solution approaches are proposed for the robust JBPS problem,each one leading to a different computational algorithm.Simulation results are presented to validate the robustness and efficiency of the proposed algo-rithms.Then,we investigate a MISO relay system with SWIPT.Assuming that both base station(BS)and relay station(RS)are equipped with multiple antennas,we study the joint transceiver design problem for the BS beamforming vectors,the RS amplify-and-forward(AF)transformation matrix and the power splitting(PS)ratios at the single-antenna receivers.The aim is to minimize the total transmission power of the BS and the RS under both SINR and EH constraints.Employing the concept of alternating optimization(AO)and switched relaying(SR),both robust and non-robust algorithms are proposed to address the highly non-convex optimization problem.Specially,in the proposed switched relaying scheme,the RS is equipped with a codebook of permutation matrices.For each permutation matrix,a latent transceiver is designed which consists of BS beamforming vectors,optimally scaled RS permutation matrix and receiver PS ratios.For the given CSI.the optimal latent transceiver with the lowest total power consumption is selected for transmission.Simulation results are presented to validate the effectiveness of all the proposed algorithms.Furthermore,we propose joint transceiver design algorithms for the FD K-pair multiple-input multiple-output(MIMO)interference channel with SWIPT.To mitigate and exploit the complex interference,we consider two important utility optimization problems,i.e.,the sum power min-imization problem and the sum-rate maximization problem.AO-based algorithms are proposed to address these problems with proper mathematical manipulations.Furthermore,with the aid of fixed beamformers(namely,the maximum ratio transmission(MRT)and the maximum signal-to-interference-leakage(SIR)beamformer),simplified algorithms are provided to reduce the compu-tational complexity.Simulation results are presented to validate the effectiveness of the proposed algorithms.Finally,we studies the joint transceiver design for a FD cloud radio access network with SWIPT.In the considered network,a number of FD remote radio heads receive information from uplink users,while transmitting both information and energy to a set of half-duplex(HD)downlink users with power splitting receivers.We aim to minimize the total power consumption with both uplink-downlink quality-of-service(QoS)constraints and EH constraints.The resulting problem is challenging because various design parameters such as the transceiver beamformers,the uplink transmit power and the receive power splitting ratios are tightly coupled in the constraints.Three d-ifferent solution approaches are proposed for the joint transceiver design problem,each one leading to a different numerical algorithm.In the first design approach,we propose an AO-based algorithm and show that the algorithm can monotonically converge to a KKT point of the problem,despite the fact that the optimization variables are nonlinearly coupled in the constraints.In the second design approach,we employ the CCCP concept to approximate the original nonconvex constraints with convex ones and illustrated that in each iteration of the CCCP-based algorithm all the transceiver parameters can be handled by solving only one problem.Also,the KKT convergence of this al-gorithms is guaranteed.Finally,two heuristic algorithms are presented to demonstrate that fairly good performance can be achieved with much reduced complexity.Simulation results validate the effectiveness of the proposed algorithms as compared with the traditional HD scheme.