scholarly journals Performance analysis of spectral/spatial of OCDMA system using 2D hybrid ZCC/MD code

Author(s):  
Rima. Matem ◽  
S. A. Aljunid ◽  
M. N. Junita ◽  
C.B.M Rashidi ◽  
Israa Shihab Aqrab

This paper proposes a new spectral/spatial code for Spectral Amplitude Coding in Optical Coding Division Multiple Access (SAC-OCDMA) called two-Dimensional hybrid ZCC/MD code. The new code combines two of the one –dimensional codes which are Zero Cross Correlation (1D ZCC) and Multi-Diagonal code (1D MD). Moreover, it produces a zero cross correlation property for each code. The main goal of this proposed code is to mitigate Phase Induced Intensity Noise and eliminate Multiple Access Interference (MAI). This proposed code can provide a better performance comparing to other codes as 2D FCC/MDW and 2D DPDC according to the obtained numerical analysis.

2020 ◽  
Vol 41 (3) ◽  
pp. 295-304
Author(s):  
A. Bouarfa ◽  
M. Kandouci ◽  
A. Garadi ◽  
H. Djellab

AbstractIncreasing the number of users presents a limitation in one-dimensional (1D) spectral amplitude coding (SAC) for Optical Code Division Multiple Access (OCDMA) system. In order to overcome this disadvantage, a new architecture of the two-dimensional wavelength/spatial SAC-OCDMA system using the multi-diagonal (MD) code has been proposed. The 2D-MD code possesses the same properties of 1D-MD code, which leads to total suppression of the multiple access interference. Unlike conventional receivers used in precedent studies, where the phase-induced intensity noise (PIIN) is a drawback, the suggested structure not only eliminates PIIN but reduces the system architecture. The results show that the user’s number reached by the proposed system is the user number’s multiplication of the 1D system and the couplers’ number. Moreover, the new 2D-MD system presents good performances at the high data rate.


2014 ◽  
Vol 699 ◽  
pp. 931-936
Author(s):  
Che Beson Mohd Rashidi ◽  
S.A. Aljunid ◽  
F. Ghani ◽  
H.A. Fadhil ◽  
M.S. Anuar

This paper presents a new Alleviation Interference Scheme (AIS) for Spectral Amplitude Coding (SAC) - Optical Code Division Multiple Access (OCDMA) coding approaches. The AIS SAC-OCDMA systems is demonstrated by utilizing the Flexible Cross Correlation (FCC) code. The FCC code has advantages, such as flexible cross-correlation property at any given number of users and weights, as well as effectively reduces the impacts of phase induced intensity noise (PIIN) and multiple-access interference (MAI). The results indicated good performance whereas the FCC code offers 100%, 207% and 471% percentage larger number of active users compared to MDW W=4, Hadamard and MFH W=8 codes, respectively. Finally, the FCC code has low receive power Psr = -18 dBm which is expected to be more significant for future SAC-OCDMA coding systems.


2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Ahmed Garadi ◽  
Boubakar S. Bouazza ◽  
Abdelkader Bouarfa ◽  
Khansae Meddah

Abstract This article presents a novel encoder technique of spectral amplitude coded multiple access (SAC-OCDMA) systems. The proposed technique is based on two orthogonal polarization states of the same one dimensional optical code. This method is usually applied to increase the number of simultaneous users in a network, and it can double the number of potential users against the one-dimensional code. The results obtained in this work show that optical zero cross-correlation code can accommodate more users simultaneously for the typical bit error rate of optical communication system of ${\ }{10^{ - 9}}$ .


2017 ◽  
Vol 38 (1) ◽  
Author(s):  
Navpreet Kaur ◽  
Rakesh Goyal ◽  
Monika Rani

AbstractThis manuscript deals with analysis of Spectral Amplitude Coding Optical Code Division Multiple Access (SACOCDMA) system. The major noise source in optical CDMA is co-channel interference from other users known as multiple access interference (MAI). The system performance in terms of bit error rate (BER) degrades as a result of increased MAI. It is perceived that number of users and type of codes used for optical system directly decide the performance of system. MAI can be restricted by efficient designing of optical codes and implementing them with unique architecture to accommodate more number of users. Hence, it is a necessity to design a technique like spectral direct detection (SDD) technique with modified double weight code, which can provide better cardinality and good correlation property.


2018 ◽  
Vol 39 (2) ◽  
pp. 215-221 ◽  
Author(s):  
Manisha Bharti ◽  
Manoj Kumar ◽  
Ajay K. Sharma

AbstractThe main task of optical code division multiple access (OCDMA) system is the detection of code used by a user in presence of multiple access interference (MAI). In this paper, new method of detection known as XOR subtraction detection for spectral amplitude coding OCDMA (SAC-OCDMA) based on double weight codes has been proposed and presented. As MAI is the main source of performance deterioration in OCDMA system, therefore, SAC technique is used in this paper to eliminate the effect of MAI up to a large extent. A comparative analysis is then made between the proposed scheme and other conventional detection schemes used like complimentary subtraction detection, AND subtraction detection and NAND subtraction detection. The system performance is characterized by Q-factor, BER and received optical power (ROP) with respect to input laser power and fiber length. The theoretical and simulation investigations reveal that the proposed detection technique provides better quality factor, security and received power in comparison to other conventional techniques. The wide opening of eye in case of proposed technique also proves its robustness.


2018 ◽  
Vol 39 (4) ◽  
pp. 459-462 ◽  
Author(s):  
Monika Rani ◽  
Harbax Singh Bhatti ◽  
Vikramjeet Singh

Abstract In this manuscript, we have analyzed a Spectral Amplitude Coding-Optical Code Division Multiple Access (SAC-OCDMA) System. The system performance is enhanced by reducing the effect of Multiple Access Interference (MAI) using uniform Fiber Bragg Gratings (FBGs) encoders and decoders at central office and subscriber’s end. The results are verified through a mathematical model and Modified Double Weight (MDW) codes for the proposed system using Adomian Decomposition Method (ADM). Further, we have demonstrated SAC-OCDMA system for transmission of 40 Gbps data rate up to a distance of 80 km by increasing the number of FBGs. The proposed system has been analyzed in terms of distance, bit error rate (BER) and Quality Factor.


Author(s):  
M. K.A. Abdullah ◽  
S. A. Aljunid ◽  
M. D.A. Samad ◽  
S. B.A. Anas ◽  
R. K.Z. Sahbudin

Many codes have been proposed for optical CDMA system as discussed in Svetislav, Mari, Zoran, Kosti, and Titlebaum (1993), Salehi (1989), Liu and Tsao (2002), Maric, Moreno, and Corrada (1996), Wei and Ghafouri-Shiraz (2002), and Prucnal, Santoro, and Ting (1986). Optical code division multiple access (OCDMA) has been recognized as one of the most important technologies for supporting many users in shared media simultaneous, and in some cases can increase the transmission capacity of an optical fiber. OCDMA is an exciting developments in short haul optical networking because it can support both wide and narrow bandwidth applications on the same network, it connects large number of asynchronous users with low latency and jitter, and permits quality of service guarantees to be managed at the physical layer, offers robust signal security and has simplified network topologies. However, for improperly designed codes, the maximum number of simultaneous users and the performance of the system can be seriously limited by the multiple access interference (MAI) or crosstalk from other users. Another issue in OCDMA is how the coding is implemented. The beginning idea of OCDMA was restricted in time domain, in which the encoding/decoding could not been fully utilized in optical domain. Therefore a new coding in OCDMA has been introduced based on spectral encoding (Kavehrad & Zaccarin, 1995; Pearce & Aazhang, 1994; Smith, Blaikie, & Taylor, 1998; Wei & Ghafouri-Shiraz, 2002). The system, called Optical Spectrum CDMA, or OS-CDMA, has the advantage of using inexpensive optical sources, and simple direct detection receivers. In this article with an emphasis on the Spectral Amplitude Coding scheme, a new code known as Khazani-Syed (KS) code is introduced.


Photonics ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 60 ◽  
Author(s):  
Kai-Sheng Chen

Supporting multi-rate transmission is an essential factor in current optical packet switching (OPS) networks. In this paper, the author studied a multi-rate scheme capable of forwarding packets with different signal rates based on label switching. The multiple-code (MC) technique was employed to label a packet by conveying its payload bits to multiple optical code-division multiple-access (OCDMA) labels. Spectral-amplitude-coding (SAC), which represents the chips in an OCDMA code as a set of wavelengths, was introduced to remove the multiple-access interference (MAI) from the overlapping among labels. The author tested the system effectiveness by conducting numerical analysis to formulate bit-error probability (BEP) and spectral efficiency (SE). The simulation results showed that the proposed network had a stable BEP performance when switching the packet flows of multiple data-rates.


2019 ◽  
Vol 9 (7) ◽  
pp. 1513
Author(s):  
Kai-Sheng Chen

We present packet switching applications based on extended spectral-amplitude-coding (SAC) labels in generalized multi-protocol label switching (GMPLS) networks. The proposed approach combines the advantages of wavelength-division multiplexing (WDM) and optical code-division multiple access (OCDMA). The extended SAC labels preserve the orthogonal property to avoid the effect of multiple access interference (MAI) shown at the decoder. We investigate the node architecture of label generation/recognition based on arrayed waveguide grating (AWG). Combining cyclic-shifted maximal length sequence (MLS) codes with the wavelength routed property of AWG simplifies the node structure. The simulation results show that the proposed labels achieve good performances against receiver noise due to the low average cross-correlation values. Under a given bit-error-rate (BER), the switching efficiency of the extended SAC labels outperforms the previous OCDMA schemes, as the network nodes are capable of processing a large number of labels simultaneously.


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