Interference Spread Spectrum Communication System Simulation

As a novel communication mode, the spread spectrum communications are widely used in military communications, satellite communications and C 3I (Command, Control, Communications & Intelligence) system because of its well multi address access, low probability interception, the excellent performance of anti-interference and secrecy. The effective jamming for spread spectrum communications systems becomes the key to get the victory of electronic war, so it is very important to research the effectiveness of jamming and interference referred to the direct sequence spread spectrum (DS-SS) and frequency hopping spread spectrum communication system.In this dissertation, DS-SS, FH-SS system are profoundly studied. Many kinds of effective jamming on them are founded out. The main work includes: The study of the key techniques in both DS/DPSK system and FH/BFSK system, the modeling and simulation of them; the evaluation and simulation of various jamming on them respectively and the study of a phase estimation algorithm for FH/DPSK system.In the first part, the techniques of Costas carrier tracking and non-coherent PN sequence tracking in digital receiver for DS/DPSK system are studied. The dissertation analyzes its mathematical models and design of parameters, and finishes its simulative model on simulink platform. Through the experiment, the dissertation testifies that the mathematical model is correct and simulation results can approximately reflect the performance of real system.The optimum jamming bandwidth and optimum jamming frequency for DS system are mathematically analyzed. The simulative experiment is carried out on the DS/DPSK model. Then the dissertation compares the theoretical analyses and the computer simulation results, and testifies the correctness of these analyses. In the meanwhile, the modeling and simulation of jamming for a specific satellite communication data link are finished. The simulation results indicate that the pulse jamming is more efficient than single-tone jamming.The dissertation studies a parallel acquisition algorithm based on matched filters for FH-SS system and finishes modeling and simulation on simulink, then builds non-coherent tracking simulation model for FH/BFSK. The simulation results are consistent with the theoretical analyses.The effectiveness of broadband noise, partial bandwidth noise and multi-tone jamming are deeply studied. The jamming simulation experiment is carried out on the FH/BFSK model. Then the dissertation compares the theoretical analyses and the computer simulation result, and testifies multi-tone jamming is more efficient than noise jamming. Finally, this dissertation studies a phase estimation algorithm for FH/DPSK system, using it to estimate the phase of each hop to gain more power efficiency.