Design And Implementation Of Terahertz High Speed Communication Baseband System

In the 5th generation mobile networks(5G)and beyond 5G era,the demand for the data transmission in wireless communications is explosively growing,and the increasingly scarce spectrum resources can no longer meet the demand.Thus,finding more available spectrum resources is an urgent problem to be solved for the development of communications in the future.In the past few years,the terahertz frequency band has attracted extensive attention with its rich spectrum resources.In addition,with the ability of transmitting the data rate more than 100 Gbps,the terahertz communication is an effective technique to meet the demand of future communications.It is significant to study the ultra-high-speed baseband processing platforms of the terahertz wireless communications for the development and application of it in the future.In this thesis,the baseband processing platform for the terahertz high-speed communication is investigated,and the baseband system with the transmission rate up to 10 Gbps is designed and implemented.The main research works of this thesis are as follows:Firstly,this thesis simulates and analyzes the atmospheric transmission characteristics of terahertz waves,and use the 220 GHz frequency for the design.The transmission characteristics of the wireless channel in this band are analyzed,finding that the terahertz channel has the characteristics of large frequency deviation and uneven inband.The transmission characteristics of the wireless channel for this frequency,it is concluded that the terahertz channel has the characteristics of large frequency deviation and non-flatness in-band.With comparing the advantages and disadvantages of the single carrier system and the Orthogonal Frequency Division Multiplexing(OFDM)system,this thesis uses the OFDM system for the baseband design.Secondly,this thesis designs and simulates a high-speed baseband link scheme based on the performance requirements of the baseband link.At the first,this thesis designs the serial frame structure of the physical layer and adopts a 16-phase parallel computing scheme.Then,the key technical scheme of the baseband transceiver is designed based on the parallel structure.Finally,the corresponding algorithms and system performance are simulated and analyzed to verify the feasibility of the baseband system design.Thirdly,this thesis implements the baseband transceiver system based on the Field Programmable Gate Array(FPGA)hardware implementation platform.At the first,this thesis designs the overall implementation structure of the physical layer,and detailed introduces the implementation process of the key modules,in which an ultra-high throughput Low Density Parity Check Code(LDPC)codec is designed and implemented.Then,the optimization methods for the key modules are given.Finally,resource analysis and performance evaluation of the key modules and the system are performed.Fourthly,this thesis builds an experimental system for the terahertz wireless communication.And the experimental results verify that the various indicators of the baseband system can meet the expectations of the design.In the system,the center frequency of the baseband transmission signals is 1.6GHz and the bandwidth of it can reach to 2.6GHz.Besides,with 16 QAM modulation,the rate of the port reaches to10.4Gbps.In addition,it is verified that the system has a good performance for the video transmission at the distance of 1.3km.In sum,this thesis proposes a baseband system design for the terahertz point-to-point wireless communication with high-speed,low-complexity,and high-performance.Through theoretical analysis,simulation verification,hardware implementation and actual test,this thesis designs and implements the baseband system.And it plays an important role in improving the data rate and transmission distance of the terahertz wireless communication.