PERFORMANCE EVALUATION OF DIRECT SEQUENCE SPREAD SPECTRUM UNDER PHASE NOISE EFFECT WITH SIMULINK SIMULATIONS

Abstract

In this work we have shown that the effect of phase noise on Direct Sequence spread spectrum signal when the phase noise level densities are high over AWGN and Fading channels. We have used the values generated by the Error-rate Calculation. Values generated by the Error-rate block for different noise levels where shown in table 1. The phase noise level density (PNLD) was varied from -20dBc/Hz to -120dBc/Hz in step of -20dBc/Hz. For each substitution, the model was simulated and results obtained and tabulated. In all, results showed that phase noise on DS-SS decreases as values of PNLDs in the Phase Noise block decreases. I have also compared the results which showing that BER is more in case of fading instead of AWGN. It also shown that BER is minimum when there are no phase noise considerations. In this work we have also compare two user’s BER transmitting at same time with different PN Sequence and shown that each having no effect over each other. I have used different PN Sequence for simulations and each shown in table 3.