The Mitigation of MAI for OOK-CDMA Systems with Optical Hard-Limiter by Transmitting Optical Pulses with Multiple Intensities

摘要

Generally, optical code-division multiple-access(CDMA) systems suffer from multiple access interferences (MAI) from other simultaneous users. As the number of simultaneous users increases, the bit error probability degrades because the amount of MAI increases. In order to reduce the MAI, a double optical hard-limiter(OHL) has been proposed where the OHLs are placed in front of and in back of the optical correlator referred to as the first OHL and second OHL, respectively[1]. However, when the interference pulses hit into all weighted position of desired user, the number of optical pulses after the correlation process is the same as the number of weights. Thus, when the desired user transmits a bit "0", the received bit is wrongly decided a bit "1".