| With the rapid development of information technology and multimedia technology,the transmission demand of mobile data traffic increases exponentially.However,the frequency band used by the existing wireless network tends to be saturated and the carrying capacity is limited,which cannot meet the increasing demand for data transmission.Therefore,it is urgent to develop new spectrum resources.Terahertz communication technology,because of its high frequency band,available bandwidth,can support high-speed data transmission,is becoming a research hotspot in the next generation wireless network.This thesis designs and implements the physical layer of the terahertz communication system with a transmission rate of 100Gbps.The main work is as follows:First,the physical layer design of terahertz communication system is given.Aiming at the application scenario of point-to-point one-way communication at short distance,the channel model is analyzed,and then according to the core index of100Gbps transmission rate,the assumption of baseband 128-phase parallel processing is proposed.Meanwhile,in order to reduce the hardware bandwidth requirements,the physical layer adopts zero IF architecture and OFDM modulation mode.Finally,combined with the typical communication system transceiver structure,complete the overall scheme design.Secondly,principle derivation and simulation analysis are made for pre-equalization and time synchronization technology in physical layer.In view of the frequency selective attenuation caused by DAC and ADC,the pre-equalization technology is used to compensate.In the baseband self-looped test scenario,the SNR of receiving end demodulation is increased by 0.6d B.A synchronization strategy for parallel multiphase processing of physical layer is proposed,which can control the synchronization error within one symbol period.Thirdly,a joint correction algorithm for IQ imbalance is proposed.Firstly,the IQ imbalance and frequency offset problems in the Terahertz communication system are modeled and analyzed.Then,a low complexity four-branch frequency domain LMS algorithm is proposed,and the effectiveness of the algorithm is verified by the simulation results in different channels.Finally,the implementation process of the algorithm is explained in detail.Finally,the performance of physical layer of terahertz communication system is verified experimentally.First,the physical layer implementation platform and test environment are described.Then,in the baseband self-loopback test scenario,the physical layer performance meets the scenario requirements and the transmission rate reaches 104Gbps.Finally,in the test scenario of terahertz frequency band,QPSK modulation mode is adopted to achieve 52Gbps transmission rate and the bit error rate is lower than10-6,meeting the demand of ultra HD video transmission.In this thesis,zero IF system is adopted to design and implement the physical layer of terahertz communication system with transmission rate up to 100Gbps.The performance of physical layer is verified by theoretical simulation and practical test,which has reference significance for the realization of Terahertz high-speed communication system. |
