A novel method for performance improvement of optical CDMA system using alterable concatenated code

Qiu, Kun; Zhang, Chongfu

doi:10.1016/j.optcom.2006.11.036

Cited by 10 publications

(7 citation statements)

References 31 publications

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“…For a given prime, hybrid FH/TS 2-D codes can be expressed by In addition, we assume that number of active users of system is k. For one user, the probability of hits between i users of k-l users and this user is qi,k-l =qi(1-q)k-l-i (10) The number of i users selected from k-I users is (~-l) . For given active users k and the threshold Th, then BER of OOK-OCOMA system can be expressed as lk-l…”

Section: B the Ccc-based Frequency-hoppingitime-spreading (Fhits) Codesmentioning

confidence: 99%

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Cubic congruence codes used in optical two-dimensional codes to increase capacity of optical codes and analysis of its performance

Zhang

Qiu

2009

2009 International Conference on Communications, Circuits and Systems

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In this paper, we develop quadratic congruence codes (QCC) to cubic congruence codes (CCC), propose and analyze a new FUlTS two-dimensional (2-D) code by using the QCC and the CCC, named as the QCC/CCC 2-D codes. In contrast to the conventional QCC-based I-D and QCC-based FUlTS 2-D optical codes, our analysis indicates that the performance and the codes capacity of the CCC-based I-D and CCC-based FUlTS 2-D codes can be improved effectively at the same condition, respectively. These results show that the designed codes are feasible, these codes can support more users in optical code division multiple access (OCDMA).number of active users with BER performance increasing. To solve this problem, we firstly introduce the theory of cubic congruence codes (CCC) [8], develop the QCC to this CCC, and construct a new FH/TS-based 2-D DOC using the CCC and QCC, which is named as the QCC/CCC 2-D codes.The rest of this paper is organized as follows. Section II contains the basic principle and construction ofthe CCC. The QCC-and CCC-based FH/TS 2-D codes are proposed and designed. In Section III, the performance of the QCC/CCC-based FH/TS codes is analyzed and compared to the previous codes. Section IV concludes this work.

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Section: B the Ccc-based Frequency-hoppingitime-spreading (Fhits) Codesmentioning

confidence: 99%

“…The conventional on-off-keying (OOK) OCOMA system [10] is considered in this work. BER performance is determined by the hits between the interference and the intended codes.…”

Section: Performanc E Analysis An D R Esu Ltsmentioning

confidence: 99%

Cubic congruence codes used in optical two-dimensional codes to increase capacity of optical codes and analysis of its performance

Zhang

Qiu

2009

2009 International Conference on Communications, Circuits and Systems

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“…Therefore, one goal when designing OCDMA systems is to achieve desirable properties of the transmitted and received signals especially to reduce the impact of the MAI. MAI is the interference resulting from other users transmitting at the same time, which is the main effect limiting the effective BER for the overall system [1].…”

Section: Introductionmentioning

confidence: 99%

Study of direct detection technique for zero cross correlation code in OCDMA

Rashidi

Anuar

Aljunid

2010

International Conference on Computer and Communication Engineering (ICCCE'10)

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This paper investigates the performance of direct detection technique for zero cross correlation code in Optical Code Division Multiple Access (OCDMA) which is a better technique to reduce Multi Access Interference (MAI). MAI is the main reason for performance degradation in optical CDMA especially when large numbers of users are involved. The implementation of direct detection whereby only a pair of decoder and detector is required as opposed with two pairs in the AND subtraction detection technique. OptiSystem Ver.7 has been used for simulation on system's performance.It is possible since the code properties posses' one clean signal chip for each of the channels. Subsequently, phase-induced intensity noise (PIIN) is suppressed at the receiver, thus the system performance is improved in term of signal to noise ratio and bit error rate. It has been shown that by using direct detection technique is better compare with other technique such as AND subtraction technique in ZCC code system as the varying the number of user is related to the power level of the received power is lower for BER 10 -9 . A larger number of users have higher insertion loss and smaller output power. For ZCC code, direct detection technique can support higher number users than the conventional technique because the number of filters at the receiver is reduced, thus a smaller power loss.

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“…Another class of error correction codes, known to be more efficient than BCH on Gaussian symmetric channel is Low Density Parity Check (LDPC) codes [16][17][18][19][20][21]. They have been already applied in optical communications [19][20][21][22][23] and it has been shown that the performances are significantly enhanced. However, even if they have been used to illustrate the MAI correction in OCDMA systems [23], no LDPC code scheme taking into account the specific MAI distribution has been developed and presented so far.…”

Section: Introductionmentioning

confidence: 99%

“…They have been already applied in optical communications [19][20][21][22][23] and it has been shown that the performances are significantly enhanced. However, even if they have been used to illustrate the MAI correction in OCDMA systems [23], no LDPC code scheme taking into account the specific MAI distribution has been developed and presented so far.…”

Section: Introductionmentioning

confidence: 99%

Performance of OCDMA system with FEC based on interference statistical distribution analysis

Sahuguède

Julien-Vergonjanne

Cances

2009

Trans Emerging Tel Tech

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International audienceThe optical code division multiple access (OCDMA) technique has been investigated for several years as a promising alternative to provide multiple access in high speed optical networks. However, due to the use of binary on off keying (OOK) modulation, an inherent main performance limitation is multiple access interference (MAI), following a specific distribution. In order to reduce errors induced by MAI, it is necessary to take into account this specific statistic when applying forward error correction (FEC) with soft decision decoding. In this paper, we analyse the MAI distribution in order to determine FEC soft decoding calculation rules. The study is performed for a low density parity check (LDPC) code scheme over an OCDMA system using two-dimensional (2-D) OCDMA spreading codes. The a priori information required for soft decoder initialisation is calculated according to the specific OCDMA channel statistic. The enhancement provided by the decoding algorithm adaptation confirms that it is important to take into account the specific MAI distribution as described in this paper. Finally, we show that, despite the loss of available data rate linked to the addition of redundancy, the data rates per user can significantly be increased thanks to this efficient error correction scheme. Copyright © 2009 John Wiley & Sons, Ltd

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A novel method for performance improvement of optical CDMA system using alterable concatenated code

Cited by 10 publications

References 31 publications

Cubic congruence codes used in optical two-dimensional codes to increase capacity of optical codes and analysis of its performance

Cubic congruence codes used in optical two-dimensional codes to increase capacity of optical codes and analysis of its performance

Study of direct detection technique for zero cross correlation code in OCDMA

Performance of OCDMA system with FEC based on interference statistical distribution analysis

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