| Summary: | 碩士 === 國立成功大學 === 電機工程學系碩博士班 === 91 === CDMA technology has been popular topical subject applied in the RF domain communication system. And, a spread spectrum fiber-optic local network utilizing high-bandwidth optical processing was demonstrated previously. In CDMA systems a receiver has to detect a signature sequence in the presence of interferences in the form of transmissions from other users. So each user has its own signature code to access the network. To increase the simultaneous users in the system, the collisions in the receiver must to be lower down. 2-D codes have the advantages of maintaining good correlation properties in 1-D codes to reduce collisions, smaller code length then 1-D codes with supporting the same number of simultaneous users, and even better performance than 1-D codes in many other ways. Here, we combine previously discussed 1-D maximal-length sequence (M-sequence) codes with time spreading and wavelength hopping techniques to develop a new hybrid system. We also apply the new developed hybrid code sequences into the synchronous and asynchronous OCDMA systems. In order to analyze the performance of the hybrid system, we compare the performance with the proposed prime-hop system. In this proposed hybrid system, it has the advantages of good correlation properties for asynchronous system and more simultaneous users with simpler and lower cost configuration in 2-D systems.
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