Direct-Detection Optical Asynchronous CDMA Systems with Double Optical Hare-Limiters: APD Noise and Thermal Noise

摘要

Performance of optical asynchronous code- division multiple-access (CDMA) systems with double optical hard-limiters is analyzed in the presence of avalanche photodi- ode (APD) noise and thermal noise. Optical orthogonal codes (OOC's) are employed as signature sequence codes. In the anal- ysis, chips are assumed to be synchronous among users: the chip synchronous case. Thus, the performance results in the upper bound on the performance of the asynchronous system. The re- sults show that the optical asynchronous CDMA systems with double optical hard-limiters have good performance in the pres- ence of the APD noise and the thermal noise even when the number of simultaneous users is large.