Low-precision Quantization Receiver Design For High Data-rate Terahertz Communications

Analog-to-Digital Converter(ADC)has a very important application in wireless communication receivers.Higher data-rate communication and lower power consumption volume have become the future development direction of the communication industry.Traditional high-precision ADCs have lower sampling rates,while high-precision,high sampling-rate ADCs have higher power consumption and are not suitable for mobile devices in the future high data-rate communication systems.Terahertz wireless communication has attracted extensive attention in the field of wireless communication due to its Gigabit transmission rate.It is also an important direction in the field of terahertz technology,and has significant advantages compared with the existing low-carrier-frequency and narrow-bandwidth communication.At present,the terahertz band mainly has three communication windows,0.11 THz,0.22 THz and 0.34 THz.It can provide communication bandwidth of nearly 40 GHz,which is much higher than the existing millimeter wave communication,and the single carrier transmission data-rate can reach 10 Gbps and develop to 100 Gbps.The application prospects are very broad.The sampling rate and input bandwidth of the ADC gradually become a factor limiting the transmission rate of the terahertz communication,while the emergence of low-precision quantization technology(1~3bit)solves this problem well.A large number of research and applications have proved that the low-precision quantization technology have many advantages in terms of power consumption,storage,complexity,etc.,especially the feasibility of 1-bit quantization in UWB communication systems.It is also suitable for terahertz communication with large bandwidth characteristics.The second chapter of this thesis firstly introduces the basic principle and structure type of analog-to-digital converter,and lists some indicators that affect the performance of the device.Subsequently,by analyzing the channel capacity problem under different channel types,the influence of low-precision quantization technology on channel capacity is derived.When SNR=10dB,2-bit quantization can achieve full-precision(12~14-bit quantization)channel capacity.85%.Finally,through the simulation comparison MP channel estimation algorithm,sequence correlation estimation algorithm,oversampling technology and the introduction of jitter signal compensation algorithm for low-precision quantization,it is found that without compensation,3-bit quantization does not use compensation algorithm.Compared with the full-precision quantization loss,the performance is about 3dB.After using the compensation algorithm,some performances are close to full-precision quantization,which further proves the feasibility of lowaccuracy quantization technology in communication systems.The third chapter introduces the design scheme of hardware experiment platform based on low-precision quantization.Considering the theoretical basis of Chapter 2,it is determined that the 3-bit quantized ADC is used as the core of the communication receiver.The main work of the hardware experimental platform is divided into two parts: 3-bit quantization analog-to-digital converter module design and digital baseband processing platform design.In the hardware design process,the main implementation of the program,chip selection,schematic drawing and board implementation,including power management design,clock design,memory design and digital circuit design.The digital baseband processing platform uses a Field-Programmable Gate Array(FPGA)chip as the core to implement communication algorithms such as signal conditioning,channel estimation,and data forwarding.The fourth chapter is based on the hardware experiment platform designed and manufactured in the previous chapter.The modules required in the terahertz communication experiment process are tested.The debugging part is from shallow to deep,from sub-module debugging to overall system joint debugging.The rationality of the scheme design and the analysis and summary of the problems encountered in the debugging process ensure that the hardware experimental platform can work stably.Finally,combined with the channel estimation,frequency offset estimation and oversampling compensation techniques under low-precision quantization,the 3-bit quantization ADC is used to realize the QPSK modulation signal close-range terahertz communication experiment with 4Gbps communication rate.The system error rate reaches the level of 1e-7.