Starting from the configuration of the optical prime code, a kind of key signature code for the optical code-division multiple access （OCDMA） system, based on the linear congruence theory in the finite Galois field,...Starting from the configuration of the optical prime code, a kind of key signature code for the optical code-division multiple access （OCDMA） system, based on the linear congruence theory in the finite Galois field, the correlation properties of the basic prime code, the extended prime code and the modified prime code are mathematically analyzed, the distribution of cross-correlation values is given and the overlap area of ＂1＂s in the case of periodically circularly shifting is indicated. It is mathematically demonstrated that the maximum cross-correlation of the basic prime code is 2, and that of the extended prime code and the modified prime code is 1. The integrated correlation analysis process is proposed. The signal-interfere ratio （SIR） and the BER performance of the systems employing different signature codes are calculated, respectively, and the performances of OCDMA systems employing different signature codes mode are compared.展开更多
A new segmented correlating decoder of synchronous optical CDMA using modified prime sequence codes is proposed. The performance of the proposed system is analyzed under the assumption of Poisson shot noise model for ...A new segmented correlating decoder of synchronous optical CDMA using modified prime sequence codes is proposed. The performance of the proposed system is analyzed under the assumption of Poisson shot noise model for the receiver photodetector. The decoder technique is shown to be more effective to improve the bit error probability performance than the method using an optical hard-limiter.展开更多
Optical orthogonal code is the main signature code employed by optical CDMA system. Starting from modern mathematics theory, finite projective geometry and Galois theory, the essential connection between optical ortho...Optical orthogonal code is the main signature code employed by optical CDMA system. Starting from modern mathematics theory, finite projective geometry and Galois theory, the essential connection between optical orthogonal code designing and finite geometry theory were discussed; find out the corresponding relationship between the parameter of OOC and that of finite geometry space. In this article, the systematic theory of OOC designing based on projective geometry is established in detail. The designing process and results of OOC on projective plane PG(2,q) and on m-dimension projective space are given respectively. Furthermore, the analytical theory for the corresponding relation between OOC with high cross-correlation and k-D manifold of projective space is set up. The OOC designing results given in this article have excellent performance, whose maximum cross-correlation is 1, and the cardinality reaches the Johnson upper bound, i.e. it realizes the optimization in both MUI and system capacity.展开更多
A passive optical network （PON） scheme based on optical code division multiplexing （OCDM） for the downstream traffics is proposed and analyzed in detail. In the PON, the downstream traffics are broadcasted by OCDM...A passive optical network （PON） scheme based on optical code division multiplexing （OCDM） for the downstream traffics is proposed and analyzed in detail. In the PON, the downstream traffics are broadcasted by OCDM technology to guarantee the security, while the upstream traffics pass through the same optical fiber by the common time division multiple access （TDMA） technology to decrease the cost. This schemes are denoted as OCDM/TDMA-PON, which can be applied to an optical access network （OAN） with full services on demand, such as Internet protocol, video on demand, tele-presence and high quality audio. The proposed OCDM/TDMA-PON scheme combines advantages of PON, TDMA, and OCDM technology. Simulation results indicate that the designed scheme improves the OAN performance, and enhances flexibility and scalability of the system.展开更多
文摘Starting from the configuration of the optical prime code, a kind of key signature code for the optical code-division multiple access （OCDMA） system, based on the linear congruence theory in the finite Galois field, the correlation properties of the basic prime code, the extended prime code and the modified prime code are mathematically analyzed, the distribution of cross-correlation values is given and the overlap area of ＂1＂s in the case of periodically circularly shifting is indicated. It is mathematically demonstrated that the maximum cross-correlation of the basic prime code is 2, and that of the extended prime code and the modified prime code is 1. The integrated correlation analysis process is proposed. The signal-interfere ratio （SIR） and the BER performance of the systems employing different signature codes are calculated, respectively, and the performances of OCDMA systems employing different signature codes mode are compared.
文摘A new segmented correlating decoder of synchronous optical CDMA using modified prime sequence codes is proposed. The performance of the proposed system is analyzed under the assumption of Poisson shot noise model for the receiver photodetector. The decoder technique is shown to be more effective to improve the bit error probability performance than the method using an optical hard-limiter.
基金The National Natural Science Foundationof China (No.:60272048) Natural Science Foundationof JiangsuEducation Department(No.04kjb510057) China Scholarship Council
文摘Optical orthogonal code is the main signature code employed by optical CDMA system. Starting from modern mathematics theory, finite projective geometry and Galois theory, the essential connection between optical orthogonal code designing and finite geometry theory were discussed; find out the corresponding relationship between the parameter of OOC and that of finite geometry space. In this article, the systematic theory of OOC designing based on projective geometry is established in detail. The designing process and results of OOC on projective plane PG(2,q) and on m-dimension projective space are given respectively. Furthermore, the analytical theory for the corresponding relation between OOC with high cross-correlation and k-D manifold of projective space is set up. The OOC designing results given in this article have excellent performance, whose maximum cross-correlation is 1, and the cardinality reaches the Johnson upper bound, i.e. it realizes the optimization in both MUI and system capacity.
文摘A passive optical network （PON） scheme based on optical code division multiplexing （OCDM） for the downstream traffics is proposed and analyzed in detail. In the PON, the downstream traffics are broadcasted by OCDM technology to guarantee the security, while the upstream traffics pass through the same optical fiber by the common time division multiple access （TDMA） technology to decrease the cost. This schemes are denoted as OCDM/TDMA-PON, which can be applied to an optical access network （OAN） with full services on demand, such as Internet protocol, video on demand, tele-presence and high quality audio. The proposed OCDM/TDMA-PON scheme combines advantages of PON, TDMA, and OCDM technology. Simulation results indicate that the designed scheme improves the OAN performance, and enhances flexibility and scalability of the system.
