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Papers by Abdelkader BOUARFA

Research paper thumbnail of Cardinality increasing of SAC-OCDMA system using novel decoder design

Journal of Optical Communications

The large number of active users that optical code-division multiple access (OCDMA) offers makes ... more The large number of active users that optical code-division multiple access (OCDMA) offers makes it an attractive technology choice. OCDMA loses its noise immunity due to non-ideal correlation since the maximum auto-correlation and minimum cross-correlation detection technique is required in OCDMA systems. There are several detection techniques like complementary detection, direct detection, etc. This paper presents a new detection technique that is particularly suited for SAC-OCDAM systems with FCZ codes. The simulation results showed that by overcoming the effects of the MAI, significant performance improvements can be achieved.

Research paper thumbnail of Comparison Between the Performance of Modified Multi-Diagonal Codes (MMD) and OOC Codes using Matlab

A new code for the optical code division multiple access (OCDMA) system with zero cross-correlati... more A new code for the optical code division multiple access (OCDMA) system with zero cross-correlation is proposed in this article. Unlike to existing codes, the Code Zero Cross-correlation (ZCC) provides good performance in terms of bit error rate (BER). The new code is called Modified Multi-Diagonal Code (MMD). MMD codes can be adapted to any weight and number of users without any constraints. By changing the weight and the number of users of both MMD and OOC and comparing codes, codes MMD showed good performance against OOC codes.

Research paper thumbnail of Enhanced Performances of W/S SAC-OCDMA System Using LDPC Code

Journal of Optical Communications, 2019

In an incoherent optical code division multiple access (OCDMA) system using amplitude spectral co... more In an incoherent optical code division multiple access (OCDMA) system using amplitude spectral coding (SAC), which exceeds 1.5 Gbps, it is difficult or impossible to make a transmission with a bit error rate better than 10–9. For this, it is necessary to associate an error correction code (ECC) to the SAC-OCDMA system. In this paper, we proposed an architecture of a two-dimensional SAC-OCDMA system (spectral (w) and spatial (s)) using multi-diagonal code (MD) as spreading code and low-density parity check code (LDPC) as ECC. According to the properties of the MD code and the proposed architecture, the phase induced intensity noise is eliminated, which has improved the performance of the system. The theoretically results shows that LDPC/2D-SAC-OCDMA allowing more than 40 users to be multiplexed compared to a non-coded 2D SAC-OCDMA system. This combination allowed us to increase the cardinality of the LDPC/SAC-OCDMA (W/S) system without using an optical hard limiter.

Research paper thumbnail of Study of the Different Optical Filters in SAC-OCDMA System

Journal of Optical Communications, 2018

Spectral amplitude coding for optical code division multiple access (SAC-OCDMA) networks has rece... more Spectral amplitude coding for optical code division multiple access (SAC-OCDMA) networks has received much attention over the last two decades. This article aims to explore the impact of encoder change on different types of optical filters, such as the Gaussian optical filter and the Bessel optical filter, for high data rates and to give an overview on importance of choosing the optimal type of optical filter according to the frequency range selected by the user is 25 and 50 GHz. SAC-OCDMA transmitter utilizes Wavelength Division Multiplexing multiplexer (WDM MUX) as an encoder, to generate a code having low cross-correlation called Random Diagonal code, and spectral direct detection as a detection technique. The change of optical filter, in WDM MUX, directly affects the performance of the system. The results show that the system for 50 GHz, with a WDM MUX, using a Gaussian optical filter has better performance compared to the optical Bessel filter and can reach a bit error rate (BE...

Research paper thumbnail of Enhanced Performances of SAC-OCDMA System by Using Polarization Encoding

Journal of Optical Communications, 2018

This article presents a novel encoder technique of spectral amplitude coded multiple access (SAC-... more 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${\ }{10^{ - 9}}$.

Research paper thumbnail of PIIN Cancellation Using a Novel Receiving Architecture for Spectral/Spatial SAC-OCDMA System

Journal of Optical Communications, 2017

Increasing the number of users presents a limitation in one-dimensional (1D) spectral amplitude c... more Increasing 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.

Research paper thumbnail of A New MIHP Code Using Direct Detection for SAC - OCDMA System

International Journal on Electrical Engineering and Informatics, 2017

Several codes have been propounded to be implemented in Optical Code Division Multiple Access (OC... more Several codes have been propounded to be implemented in Optical Code Division Multiple Access (OCDMA) using spectral amplitude coding (SAC). In this work, we suggest a new code structure for SAC-OCDMA system, we demonstrate theoretically and practically the good quality of the proposed system. The new code is called multi-identity high-power code (MIHP). This code with its architecture and facility of construction provides good performance with regard to BER. Without any constraint, MIHP codes can be adjusted to any number of users and weight. In this architecture the use of direct detection which reduces significantly the MAI. The result shows that the proposed code in SAC OCDMA system provides better performance and gave a BER equal to 8.70886e-17, the system using the suggested code can reach a length of 115 km for a bit error rate of 10 −9 without using any amplifier.

Research paper thumbnail of Optimization method based on simplex algorithm for current control of modular multilevel converters

2019 IEEE International Conference on Industrial Technology (ICIT), 2019

The paper proposes an optimization formulation of the control problem for modular multilevel conv... more The paper proposes an optimization formulation of the control problem for modular multilevel converter (MMC). The main control stage computes arm voltages on average over a fixed switching period by minimizing control errors in order to satisfy as best as possible the desired references of input, circulating and output currents, while taking into account arm voltage limits. Then, mean-values of required arm voltages are achieved by phase shift pulse-width modulation (PSPWM) by computing duty cycles for each submodule while taking into account the issue of active balancing of the capacitor voltages in a secondary control stage. The proposed optimization problems are solved by using a numerical method based on the simplex algorithm and simulation results are shown in order to support the validity of the approach.

Research paper thumbnail of Formats de modulation et codes adaptés aux communications numériques optiques à très haut débit

Research paper thumbnail of Behavior study of EDEU optical code for FE-OCDMA system

Journal of Optical Communications

The increase in the cardinality of the frequency encoding-optical code division multiple access (... more The increase in the cardinality of the frequency encoding-optical code division multiple access (OCDMA) system directly affects the length of the optical code, which leads us to find a less expensive solution. In this work, I propose an improved version of the diagonal eigenvalue Unit code (DEU) called Enhanced diagonal eigenvalue Unit code (EDEU) that is much easier in terms of construction and short in code length compared to the DEU code. The results found showed that the performance of the EDEU code exceeds the DEU code in terms of bit error rate (BER), and allowed us to multiplex about 15 more users when using the EDEU code compared to the system using the DEU code. As a result, the EDEU code is very suitable for use in access and OCDMA systems and it can be seen as a strong competitor to existing codes.

Research paper thumbnail of Cardinality increasing of SAC-OCDMA system using novel decoder design

Journal of Optical Communications

The large number of active users that optical code-division multiple access (OCDMA) offers makes ... more The large number of active users that optical code-division multiple access (OCDMA) offers makes it an attractive technology choice. OCDMA loses its noise immunity due to non-ideal correlation since the maximum auto-correlation and minimum cross-correlation detection technique is required in OCDMA systems. There are several detection techniques like complementary detection, direct detection, etc. This paper presents a new detection technique that is particularly suited for SAC-OCDAM systems with FCZ codes. The simulation results showed that by overcoming the effects of the MAI, significant performance improvements can be achieved.

Research paper thumbnail of Comparison Between the Performance of Modified Multi-Diagonal Codes (MMD) and OOC Codes using Matlab

A new code for the optical code division multiple access (OCDMA) system with zero cross-correlati... more A new code for the optical code division multiple access (OCDMA) system with zero cross-correlation is proposed in this article. Unlike to existing codes, the Code Zero Cross-correlation (ZCC) provides good performance in terms of bit error rate (BER). The new code is called Modified Multi-Diagonal Code (MMD). MMD codes can be adapted to any weight and number of users without any constraints. By changing the weight and the number of users of both MMD and OOC and comparing codes, codes MMD showed good performance against OOC codes.

Research paper thumbnail of Enhanced Performances of W/S SAC-OCDMA System Using LDPC Code

Journal of Optical Communications, 2019

In an incoherent optical code division multiple access (OCDMA) system using amplitude spectral co... more In an incoherent optical code division multiple access (OCDMA) system using amplitude spectral coding (SAC), which exceeds 1.5 Gbps, it is difficult or impossible to make a transmission with a bit error rate better than 10–9. For this, it is necessary to associate an error correction code (ECC) to the SAC-OCDMA system. In this paper, we proposed an architecture of a two-dimensional SAC-OCDMA system (spectral (w) and spatial (s)) using multi-diagonal code (MD) as spreading code and low-density parity check code (LDPC) as ECC. According to the properties of the MD code and the proposed architecture, the phase induced intensity noise is eliminated, which has improved the performance of the system. The theoretically results shows that LDPC/2D-SAC-OCDMA allowing more than 40 users to be multiplexed compared to a non-coded 2D SAC-OCDMA system. This combination allowed us to increase the cardinality of the LDPC/SAC-OCDMA (W/S) system without using an optical hard limiter.

Research paper thumbnail of Study of the Different Optical Filters in SAC-OCDMA System

Journal of Optical Communications, 2018

Spectral amplitude coding for optical code division multiple access (SAC-OCDMA) networks has rece... more Spectral amplitude coding for optical code division multiple access (SAC-OCDMA) networks has received much attention over the last two decades. This article aims to explore the impact of encoder change on different types of optical filters, such as the Gaussian optical filter and the Bessel optical filter, for high data rates and to give an overview on importance of choosing the optimal type of optical filter according to the frequency range selected by the user is 25 and 50 GHz. SAC-OCDMA transmitter utilizes Wavelength Division Multiplexing multiplexer (WDM MUX) as an encoder, to generate a code having low cross-correlation called Random Diagonal code, and spectral direct detection as a detection technique. The change of optical filter, in WDM MUX, directly affects the performance of the system. The results show that the system for 50 GHz, with a WDM MUX, using a Gaussian optical filter has better performance compared to the optical Bessel filter and can reach a bit error rate (BE...

Research paper thumbnail of Enhanced Performances of SAC-OCDMA System by Using Polarization Encoding

Journal of Optical Communications, 2018

This article presents a novel encoder technique of spectral amplitude coded multiple access (SAC-... more 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${\ }{10^{ - 9}}$.

Research paper thumbnail of PIIN Cancellation Using a Novel Receiving Architecture for Spectral/Spatial SAC-OCDMA System

Journal of Optical Communications, 2017

Increasing the number of users presents a limitation in one-dimensional (1D) spectral amplitude c... more Increasing 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.

Research paper thumbnail of A New MIHP Code Using Direct Detection for SAC - OCDMA System

International Journal on Electrical Engineering and Informatics, 2017

Several codes have been propounded to be implemented in Optical Code Division Multiple Access (OC... more Several codes have been propounded to be implemented in Optical Code Division Multiple Access (OCDMA) using spectral amplitude coding (SAC). In this work, we suggest a new code structure for SAC-OCDMA system, we demonstrate theoretically and practically the good quality of the proposed system. The new code is called multi-identity high-power code (MIHP). This code with its architecture and facility of construction provides good performance with regard to BER. Without any constraint, MIHP codes can be adjusted to any number of users and weight. In this architecture the use of direct detection which reduces significantly the MAI. The result shows that the proposed code in SAC OCDMA system provides better performance and gave a BER equal to 8.70886e-17, the system using the suggested code can reach a length of 115 km for a bit error rate of 10 −9 without using any amplifier.

Research paper thumbnail of Optimization method based on simplex algorithm for current control of modular multilevel converters

2019 IEEE International Conference on Industrial Technology (ICIT), 2019

The paper proposes an optimization formulation of the control problem for modular multilevel conv... more The paper proposes an optimization formulation of the control problem for modular multilevel converter (MMC). The main control stage computes arm voltages on average over a fixed switching period by minimizing control errors in order to satisfy as best as possible the desired references of input, circulating and output currents, while taking into account arm voltage limits. Then, mean-values of required arm voltages are achieved by phase shift pulse-width modulation (PSPWM) by computing duty cycles for each submodule while taking into account the issue of active balancing of the capacitor voltages in a secondary control stage. The proposed optimization problems are solved by using a numerical method based on the simplex algorithm and simulation results are shown in order to support the validity of the approach.

Research paper thumbnail of Formats de modulation et codes adaptés aux communications numériques optiques à très haut débit

Research paper thumbnail of Behavior study of EDEU optical code for FE-OCDMA system

Journal of Optical Communications

The increase in the cardinality of the frequency encoding-optical code division multiple access (... more The increase in the cardinality of the frequency encoding-optical code division multiple access (OCDMA) system directly affects the length of the optical code, which leads us to find a less expensive solution. In this work, I propose an improved version of the diagonal eigenvalue Unit code (DEU) called Enhanced diagonal eigenvalue Unit code (EDEU) that is much easier in terms of construction and short in code length compared to the DEU code. The results found showed that the performance of the EDEU code exceeds the DEU code in terms of bit error rate (BER), and allowed us to multiplex about 15 more users when using the EDEU code compared to the system using the DEU code. As a result, the EDEU code is very suitable for use in access and OCDMA systems and it can be seen as a strong competitor to existing codes.