Novel Hybrid Beamforming Architectures And Algorithms

The continuous growth of the number of intelligent devices and the rapid development of emerging wireless services have caused the exponential increase of the demand for wireless network traffic.Therefore,it is imminent to find novel technologies to satisfy the increasing communication requirement for 5G and beyond networks.This motivates the research on key technologies for 5G and beyond networks,i.e.,massive multiple input multiple output(MIMO),ultra-dense network,and millimeter wave(mm Wave)communications.However,the above technologies still inevitably face challenges mainly due to the high cost and power consumptions when employing multiple antennas/cells,and/or hardware components(e.g.radio frequency chains).Therefore,it is necessary to find cost-and energy-efficient solutions which still provide for high-speed wireless transmissions.This thesis mainly focuses on novel hybrid analog/digital beamforming architectures and corresponding designs for different communication frequencies.Besides,both theoretical performance analysis and numerical simulations are included.The work and contributions of this thesis can be summarized as follows:First,this thesis introduces a novel energy-efficient analog beamforming architecture with dynamic subarrays and low-resolution phase shifters for mm Wave narrowband multiuser multiple input single output(MU-MISO)systems.By combining it with typical digital beamformer,this thesis establishes a novel hybrid beamforming architecture.Aiming at maximizing the sum-rate performance,this thesis proposes two iterative algorithms and provides corresponding performance analysis.Furthermore,the energy efficiency of this novel architecture is also included to examine its feasibility in real-world situations.Next,this thesis expends the use of this novel hybrid beamforming architecture to wideband mm Wave systems.In this case,simple point-to-point scenarios with the same novel hybrid architecture for both sides are firstly studied.Then,this thesis expends this work to multiuser cases and modifies the corresponding hybrid beamforming design.Simulation results again verify the advantage of this novel hybrid architecture for wideband mm Wave systems.Finally,this these introduces a power-efficient reconfigurable intelligent surface(RIS)for traditional wireless communication systems.By combining RIS with typical fully-digital beamforming,another novel RIS-based hybrid beamforming architecture is established.Specifically,this thesis firstly considers the application of ideal RIS in wideband multiuser systems.Next,the response of practical RIS is further studied and modeled.With this practical RIS model,this thesis reconsiders the corresponding beamforming design for wideband communication systems.Research results of this thesis can not only promote the development of wireless communications and facilitate the evolution of dense and intelligent wireless networks,but also provide positive instructions(including theoretical verification and technology support)for the design and deployment of future 6G networks.