International Conference on Computer and Communication Engineering
Security enhancement for spectral amplitude coding OCDMA based on hybrid EDW/M seq. code systems
Hesham A. Bakarman, Feras N. Hasoon, Sahbudin B. Shaari, Mahamod B. Ismail
Abstract
This paper presents the security enhancement for spectral amplitude coding optical CDMA. The eavesdropper probability of error-free code detection based on hybrid code system is investigated. Enhancement Double Weight (EDW) optical CDMA scheme and M-sequence codes are used as a hybrid code system. The eavesdropper performance is based on observing the authorized transmitted signal based on classical detection theory. The eavesdropper taps a coded transmission of a particular user and performs the necessary calculations to derive the transmitter's code word from these transmissions. If an eavesdropper could be forced to tap code pulses with low SNRs, a security enhancement can be obtained. An eavesdropper would need SNR of 9.2 dB to correctly detect encoded pulses with a probability of 50 % for the hybrid scheme, which is 5 and 3 dB higher than M-sequence and EDW schemes respectively. The difference in performance of the eavesdropper's receiver with envelope detection is getting small, especially at higher SNRs.