الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
One of the major hurdles in optical burst switched (OBS) networks is the contention problem. Moreover, technical superiority of Spectral Amplitude Coding-Optical Code Division Multiple Access (SAC-OCDMA) systems over traditional Wavelength Division Multiplexing (WDM) systems in optical burst switched (OBS) networks is mainly at-tributed to the former better MAC layer performance. Nevertheless, in order to perform an accurate comparison, the investigation of the physical layer performance should be involved. In this work, we analyze the effect of Phase-Induced Intensity Noise (PIlN) on the number of active users in OBS/SAC-OCDMA systems. Our analysis shows that this effect introduces a burst error rate (BurstER) in the multiple access interference cancellation operation (not investigated before). This BurstER is a function of the num-ber of active users (10-5 @ 60 users) and would lead to worse performance than that of OBS/WDM systems. However, the choice of other signature codes, like modified quadratic congruence code family, would mitigate the PIIN effect and would push the performance of OBS/SAC-OCDMA system further above that of OBS/WDM systems. Finally, assuming an ideal WDM physical layer, we present a detailed performance com-parison between OBS/SAC-OCDMA and OBS/WDM by introducing a new burst error loss rate parameter. The results show that OBS/SAC-OCDMA performance outper-forms that of OBS/WDM when the number of tolerated bits in error per burst exceeds a certain value.
In addition, we tackle the contention problem by proposing a new contention resolution technique based on control packet (CP) buffering. In particular, a rigorous mathematical model is developed to analyze the performance of an OBS network core node employing this technique along with Just-In-Time (JIT) one way reservation protocol. The key idea, that makes this proposal novel, is that this buffering is implemented in the electronic domain, thus avoiding the complexity that exist in the optical domain solutions. A detailed evaluation of the system performance using both the burst loss probability and the steady state throughput is presented. Our results reveal that a considerable improvement in the performance is achieved when adopting the proposed technique (Burst loss rate of 10-6 can be reached).
Finally, simulation results for the mathematical model of an OBS system that employs control packet buffering, as a contention resolution technique, are presented. This results prove the validity• of the CP buffering proposal.