Code cross-correlation effects on the performance of optical cdma systems in the presence of receiver noises

Abstract

Increasing the number of simultaneous users is one of the challenging issues in incoherent and asynchronous optical CDMA systems. One solution is to increase the value of cross- correlation, λ_c. In neglecting the effect of noise, optimum value of λ_cwas obtained. In this work, with considering noise, the simultaneous effect of λ_c and transmitted power on the probability of bit error (pbe) is investigated. Our investigation is performed by employing OOC (λ_c =1) and prime code (λ_c =2) and active correlator is chosen for its robustness against the noise. The performance is analyzed for three common receiver structures, namely soft receiver (without optical hard limiter), single optical hard limiter (SHL) and double optical hard limiters (DHL). Our results show that under the same bandwidth efficiency, increasing λ_c in high power regimes decreases the pbe but increasing λ_c in low power regimes will increase pbe.