This paper reports the implementation and theoretical model for analyzing an optical CDMA/DWDM hybrid system to reduce two major problems, Inter-Symbol Interference (ISI) Four-Wave Mixing (FWM) effects improve performance of subscriber access networks by using Zero Cross-Correlation (ZCC) codes, which helps effect Multiple Access (MAI). A squeezing method is used in proposed completely suppress...

Multi-user communication traditionally uses either code division multiple access (CDMA) or time-division schemes. The chirp signals resilience to multipath and the Doppler effect makes it suitable for underwater acoustic communication. This paper presents a binary phase-coded hyperbolic frequency-modulated (BPC-HFM) multi-user proposed scheme has advantage of both linear signal, which is immune...

We consider the problem of security in the CDMA. CDMA system has wireless channels to transmit voice or data. By this reason, CDMA communication has a possibility of being eavesdropped by someone. It is known that eavesdropping in CDMA system is impossible because the voice data spreads with the PN. However, we can eavesdrop the CDMA data using FCM protocol in case that we know the ESN and the ...

To solve the degradation of the BER performance of Space-Time Block Code (STBC)/MC-CDMA system when MC-CDMA system has large number of users, we propose Unitary Space-Time Modulation (USTM)/MC-CDMA system. USTM combines STBC and baseband modulation by employing unitary matrix. USTM is designed in order not to receive signals from different transmit antennas simultaneously at the receiver. In th...

In this contribution, we propose a variant of the MC-CDMA system that offers more flexibility than the traditional MC-CDMA system. We investigate the sensitivity of this flexible MC-CDMA system to some types of synchronisation errors. This flexible MC-CDMA system is not affected by a constant phase offset or a constant timing offset, as in the proposed flexible MC-CDMA system the carriers insid...

Optical CDMA has gained increasing attention as a promising access network technology. This paper presents an optical CDMA network simulation environment based on OPNET modeler, with a focus on the simulation module implementation. We discuss the pipeline structure of optical CDMA transceivers and describe its interface with the physical layer for system integration. We also present the archite...

Code Division Multiple Access (CDMA) is probably the most interesting multiple access method provided by spread spectrum technology. CDMA refers to a multiple access method in which the individual terminals use spreadspectrum techniques and occupy the entire spectrum whenever they transmit. This paper focuses on direct-sequence spread-spectrum principles (processing gain, spreading, de-spreadin...