الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
In this thesis, an overview on optical code division muliple access (OCDMA) communication systems is presented. Focus is oriented towards random access protocols and media access control (MAC) protocols for future optical CDMA networks. A link layer protocol that supports multi-rate on (OCDMA) network is proposed based on multi-coding techniques to improve the performance of the network. The main objective is to allow users of different data rates to access the network simultaneously without affecting or reducing the networks performance. Signature sequences are achieved using one-coincidence frequency hop code/optical or-thogonal code (OCFHC/OOC) 2D codes which slightly increase the performance than OOC. Two different link layer protocols are considered in the analysis. In the first protocol, a signature code is only assigned to a single user. In the second protocol, however, a signature code is permitted to be assigned to several users after being cyclic shifted randomly. The system overall throughput and average packet delay are derived for two receiver models; namely, the correlation and chip level receivers. In the analysis, the effect of multiple access interference (MAI), the receiver shot and thermal noise are taken. The network users are classified into two classes with two different transmission rates which are 1 and 2 Codes/User for single and multi-rate class, respectively. Results reveal that, the proposed multi-rate network outperforms the traditional single rate network in terms of both average throughput and packet delay. Furthermore, number of classes is generalized. Thus, the performance of the network is even better. In conclusion, proposed network not only allows users demanding different rates to transmit their data reliably but also improves the overall performance.