Design And Implementation Of High Dynamic Burst Spread-spectrum Communication System

The spread-spectrum receiver technology under high dynamic environment is a focus and difficulty in the field of communication.The spread-spectrum receiver technology adapted to the large Doppler frequency has been widely used in GPS navigation,space telemetry and other fields.This paper deeply studies the impact of large Doppler effects on communication technology,proposing a fast synchronization technology which adapted to large Doppler frequency and has good anti-interference ability,and forms a complete set of spread-spectrum communication system under high dynamic envirionment and burst communication adapted to low SNR with hardware test equipment,FPGA hardware platforms.Contents of this paper include: Firstly,the paper introduces the basic theory of the spread-spectrum communication technology,involving in interference tolerance,spreading gain and pseudo-random code sequence which is extremely important in spread-spectrum communication technology;Secondly,this paper proposes a new synchronous technology which adapted to large Doppler effect,low SNR,and burst communication envirionment based on the original synchronization scheme,namely,carrier synchronization using "parallel sweep method + FFT algorithm" technology,Pseudo-code synchronization using the "matched filter + leadlag ring" technology,and the paper does detailed MATLAB simulation of this paper's scheme,preliminary verifying the correctness of this paper's scheme;Thirdly,the paper completes the FPGA design of the spread-spectrum communication system,presenting detailed implementation process of the synchronization technology which includes acquisition and tracking module,and doing Model Sim simulation;Forthly,with hardware test platform,including the signal source,noise source,power,FPGA chip,ADC chip,DAC chip and so on,the paper implements the hardware debugging of the spread spectrum communication system,complets the test of the actual performance of the communication system and gives the test results.The difficulty of the communication system's design lies in the design of the synchronization scheme,mainly reflected in the harsh conditions of communication,including large Doppler effect,low signal to noise ratio and sudden,but this paper proposesa set of feasible scheme based on communication conditions,and complete s the entire software design of the communication system,hardware design,hardware test,with hardware circuitry the paper completes a set of design of spread-spectrum communication system under high dynamic envirionment and burst communication,and has good communication performance.