In this study, the authors proposed a new approach to evaluate the system performance of spectralamplitudecoding-opticalcodedivisionmultipleaccess (SAC-OCDMA) systems. The system performance is evaluated based o...
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In this study, the authors proposed a new approach to evaluate the system performance of spectralamplitudecoding-opticalcodedivisionmultipleaccess (SAC-OCDMA) systems. The system performance is evaluated based on a new code called the dynamic cyclic shift (DCS) code. The bit-error-rate (BER) performance of the DCS code on high-speed SAC-OCDMA systems has been analysed and reported in this study. The most remarkable trait of the newly developed DCS code is that the cross-correlation is variable between 1 and 0, and the phase induced intensity noise is low. In order to evaluate the performance of the DCS code in high-speed SAC-OCDMA system, the mathematical analysis has been extensively derived along with the simulation analysis at 10 Gbit/s, which is carried out by using 'Optisystm (TM) ver.9 simulation software from Optiwave'. The results obtained for the DCS code were compared with those obtained from different coding schemes [e. g. random diagonal code and modified quadratic congruence code] for the same number of interfering users. It has been observed that the DCS code of BER equal to 10(-11) can support high data rate (5 Gbit/s) at 60 km transmission link.
Variable weight (VW) codes for spectral amplitude coding-optical code division multiple access system are useful in multimedia applications. VW code algorithm is proposed which is based on enhanced and modified double...
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Variable weight (VW) codes for spectral amplitude coding-optical code division multiple access system are useful in multimedia applications. VW code algorithm is proposed which is based on enhanced and modified double weight codes. The proposed algorithm can be used for any combination of weights >2. The cross-correlation among all users is at most 1. This code construction algorithm ensures higher power at receiver for higher-weight users. Lower-weight users receive less power compared with higher-weight users. The difference in received power translates as varying performance, and are useful for multimedia applications. The performance of VW code is analysed using balanced detection (BD) exclusive-OR operation and direct detection with exclusive-OR operation. VW code gives comparable or better performance than previously reported code. It is observed that supportable number of users for higher weight, at bit error rate (BER) of 10(-9) (data) are 28, 33 and 35 for random diagonal (RD) code, Khazani-Syed (KS) code and VW code, respectively, using BD. Supportable number of users for lower weight, at BER of 10(-4) (voice) are 23, 31 and 37 for RD code, KS code and VW code, respectively, using BD.
This article presents a new codethe dynamic cyclic shift codefor spectralamplitudecodingopticalcodedivisionmultipleaccesssystems. One of the important properties of the dynamic cyclic shift code is that the num...
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This article presents a new codethe dynamic cyclic shift codefor spectralamplitudecodingopticalcodedivisionmultipleaccesssystems. One of the important properties of the dynamic cyclic shift code is that the number of users can be increased without increasing the weight value. system performance was evaluated by using both theoretical analysis as well as the simulation experiment. The analysis results show that the proposed dynamic cyclic shift code can support more users in spectralamplitudecodingopticalcodedivisionmultipleaccesssystems compared to spectralamplitudecodingopticalcodedivisionmultipleaccesscodes. It was ascertained by performance evaluation that the dynamic cyclic shift code possesses ideal properties for use in spectralamplitudecodingopticalcodedivisionmultipleaccesssystems.
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