Key Technologies Research And Verification Of Trusted Transmission Waveform In Aero-based Wireless Communication

Data link,which is used to transfer formatting tactical information real-timely and automatically,is a kind of communication system based on wireless transmission mainly,aiming to connect every combat platform.At present,the key techniques of data link include remote information transfer,high dynamic and reliable communication,high rate and real-time data interaction,anti-interference,high confidentiality and so on.In this paper,we study the physical layer technology of the onboard data link,such as time-frequency synchronization,channel equalization and so on.A variable rate transmission waveform that supports far-distance and high-maneuver is designed.And it can communicate at low rate in large frequency offset and low SNR.The specific research contents include:Firstly,the demand for transmission waveform has been analysed.In this paper,the impaction of propagation loss and frequency shift on transmission waveform has been discussed.Then the link budget of transmission waveform and the accuracy requirement have been analyzed combined with its design target.Secondly,the data frame structure and waveform transmission scheme that can satisfy technical indicators have been designed Based on the theoretical analysis.And the transmission waveform was analyzed under AWGN channel by simulation tool.It was indicated in the result that,the time synchronization accuracy was limited to 1?4chip time,the frequency synchronization accuracy was limited in 0.238Hz,and the bit error of 500bps transmission waveform was less than10^-6 when SNR upper than-24dB and carrier frequency less than?100kHz;and the bit error of 100kbps transmission waveform was less than10^-6 when SNR upper than-2dB and carrier frequency less than?100kHz.Thirdly,the implementation of waveform transmission scheme was stated on the hardware platform.On the basis of the overall framework of transmission waveform,the realization of each key module of physical layer is divided and introduced,and the realization process of time-frequency synchronization and channel equalization is emphasized.In the end,the resource consumption of transmission waveform is given,and the realization of the design is verified.Finally,the design was tested under loop back,laboratory and outdoor environment.It was implied in the result that,the implementation of time-frequency synchronization are consistent with the simulation results,the code-division channel equalization is 1dB better than that of the phase-locked loop,and bit error rate of 500bps transmission waveform is 0 when SNR under-23dB and carrier frequency on?100kHz;and the bit error of 100kbps transmission waveform was less than10^-6 when SNR upper than-2dB and carrier frequency less than.In a word,a low rate transmission waveform scheme which is suitable for large frequency offset and low SNR was designed in this paper,and the feasibility of this scheme was verified through the implementation and test,which is expected to provide theoretical basis and engineering reference for the research of our country’s data link technology.