Key Technology Of Terahertz High-speed Baseband Data Transmission Based On Time-domain Equalization Research And Implementation Verification

The terahertz communication system can be divided into a baseband part and a radio frequency part.This article mainly studies the baseband part,with the purpose of designing a baseband system that can generate large-bandwidth signals and effectively resist multiple interferences such as multipath and frequency offset,so as to stably realize high-speed wireless communication.The main contributions of this article are as follows:First,analyze application scenarios and performance requirements.The communication system designed in this article is used in point-to-point communication scenarios.In this scenario,the communication channel is relatively stable and can be approximated by the AWGN(Additive White Gaussian Noiser)channel,so the time-domain equalization scheme is feasible.Moreover,point-to-point communication is often used in long-distance communication,so the signal peak-to-average ratio cannot be too high.Based on the above two points,this article adopts a single-carrier time-domain equalization scheme.The communication system design rate is 10 Gbps,and the hardware equipment signal-to-noise ratio can only support 16QAM(Quadrature Amplitude Modulation)modulation at most,so it is necessary to adopt a parallel data processing scheme.In this paper,a 16-channel parallel data processing scheme is used and the parallel signal is converted into a multi-phase signal through matrix transposition,and then sent to the DAC(Digital-to-Analog Converter)to obtain a large bandwidth signal that meets the rate requirementSecond,complete the specific scheme design and build the link to verify performance.The key to the scheme design lies in the three links of time synchronization,frequency synchronization and time domain equalization.The time domain equalization system has higher requirements for the accuracy of time synchronization.Therefore,this paper adopts the horizontal and vertical double PN(Pseudorandom Noise Code)scheme to improve the accuracy of time synchronization.The frequency synchronization scheme adopts a feedback type,because the matrix transposition increases the difficulty of realizing conventional frequency synchronization.The feedback type frequency synchronization can reduce the difficulty of realization and significantly reduce the residual frequency offset.The main body of time domain equalization is the adaptive filter,and the number of taps of the filter selected in this article is 24.After the design is completed,a link is built to verify the performance of the solution,and iterate until the requirements are met.Third,complete the project implementation and test the performance.According to the design plan,it is realized step by step and the correctness of the function is verified through behavior simulation,and then the direct connection test is carried out relying on the engineering realization platform.Mainly test transmit signal performance,time-frequency synchronization performance and system error performance.The transmitted signal power spectrum shows that the signal bandwidth is close to 3GHz,and the data transmission rate can reach 10 Gbps.Time synchronization works normally,and the numerical waveforms of each key signal basically agree with the simulation results.When the transceiver is directly connected,the SNR(Signal Noise Ratio)is about 35 d B,the test result shows that the residual frequency offset is about 5Hz,and the bit error rate is 0.The measured value basically agrees with the simulation result.This paper designs a digital baseband system for THz high-speed communication based on time-domain equalization.Complete the specific scheme design and project realization and verify the performance through actual tests.For scientific researchers engaged in research in this field,the work of scheme design,engineering implementation and actual testing in this article has certain reference significance.