Performance evaluation of an optical network employing a code division multiple access scheme based on Gold sequences

Abstract

An exact analysis of a code division multiple access (CDMA) optical system using Gold sequences is presented for two coherent modulation schemes, in terms of the bit error rate (BER) as a function of the number of simultaneous transmissions, and of the power penalty to be paid in order to allow for a given number of interferers, maintaining an acceptable BER level. The true statistics of the random variable representing the interferers is employed, and no bit synchronization among the transmitters is assumed. The chip asynchronous case has also been considered, leading to slightly better performance than the chip synchronous one. Results have been obtained employing both the periodic and the nonperiodic crosscorrelation between Gold sequences. The results show that, in many realistic network contexts, the CDMA technique can be effectively exploited without requiring any synchronization among all the stations.<>