M. S. Anuar

Enhanced performance of new family Modified Double Weight codes spectral amplitude coding optical CDMA system network

A new family of spectral/spatial spectral amplitude-coding (SAC) optical code division multiple access (OCDMA) scheme using Modified Double Weight (MDW) code is developed. The new codes are derived from Modified Double Weight codes with good cross correlation. This proposed system can suppress the phase-induced intensity noise (PIIN) by using multiuser interference (MUI) cancellation property. The proposed 2-D OCDMA MDW can offer a much larger capacity compare to the 1-D OCDMA MDW Code.

Study of rain attenuation consequence in free space optic transmission

This paper is to provide the preliminary result and activities of a research program at UNIMAP on rain attenuation in the Perlis region. The project uses the LaserBit product; model LB-2500 and LB-5000 which can maximum reach 2500 m and 5000 m with wavelength 785 nm and laser power 70 mW. The result will utilize four existing model rain attenuation and measured data will compared to calculated result to determine the validity of precipitation model and deepen the consequence of rain intensity. As additional to unwavering the measurement. Optisys software has been used to simulate the data to predict the possibility of result.

Performance analysis of 2-D Extended-EDW Code for optical CDMA system

Two-dimensional Optical Code Division Multiple Access (2-D OCDMA) has gained great interest among researchers in optical communication systems. This work is aimed to present an alternative way of formulating the spectral/spatial incoherent two-dimensional Extended Enhanced Double Weight (2-D Extended-EDW) code. This code is proposed to suppress the phase induced intensity noise (PIIN) by using multiple access interference (MAI) cancellation property. The numerical analysis shows that 2-D EDW code has a better performance, in terms of bit error rate (BER) and the cardinality compared with one-dimensional Enhanced Double Weight (1-D EDW) code. In comparison with different combinations of spatial and spectral code length for 2-D Extended-EDW code, we found that by increasing the number of time chip, it significantly enhances the performance of the system.

Phase-induced intensity noise suppression wavelength-time modified double weight codes optical code division multiple access systems

The wavelength-time modified double weight (MDW) optical division multiple access (OCDMA) scheme to reduce multiple access interference (MAI) and compensate bit error rate (BER) and phase-induced intensity noise (PIIN) in incoherent OCDMA systems is proposed. The analysis permits thorough understanding of PIIN, shot and thermal noises effect on 2-Dimensional (2-D) MDW OCDMA system performance. PIIN is the dominant noise factor in the OCDMA time-spreading scheme. The 2-D MDW code shows better tolerance to PIIN in comparison to others with enhanced system performance. We prove by numerical analysis that the PIIN is maximally suppressed by the proposed code through minimizing property of cross-correlation in comparison to the 2-D PDC and 2-D MQC OCDMA code.

Modeling and simulation of variable weight zero cross correlation code in optical access network

In this paper, we demonstrate a novel architecture of variable weight Zero Cross Correlation code in the family of Spectral Amplitude Coding(SAC) Optical Code Division Multiple Access (OCDMA) to be utilized in the triple play services of OCDMA applications based on the end users demand and requirements. This is achieved by adapting multiple weights of Zero Cross Correlation (ZCC) code onto one system to accommodate different Quality of Service (QoS) requirements. The results are characterized by bit error rate (BER) and eye pattern simulated using OptiSystem software. Results proved a successful transmission of this scheme over 20km distance thus offering flexibility of independent QoS. It is also revealed that the performance is always better for users with larger number of code weight compared to those assigned with smaller code weight.

LED spectrum slicing for ZCC SAC-OCDMA coding system

In this paper we propose a Zero Cross-correlation (ZCC) code in Optical Code Division Multiple Access (OCDMA) CDMA system based on amplitude spectral encoding of low-cost broadband sources such as Light Emitting Diode (LED). We also study how the sliced spectrum of LED can be used as a cost-effective light source in ZCC code. Our system requires only standard optical elements and simple direct-detection receivers. We show that for number of weight = 4, up to 100 users can transmit asynchronously with an average bit error rate equal to 10−9. This ZCC code also demonstrates that BER of 10−9 can be achieved within the minimum received power of −25.5 dBm.

Impact of different transceiver design on the performance of SAC-OCDMA systems

Multiple-access interference (MAI) and phase-induced intensity noise (PIIN) are the principal limitations for the performance of spectral-amplitude-coding optical codedivision multiple-access (SAC-OCDMA) systems. Focusing on increasing the performance and reducing the bit-error rate (BER), the ideal transceiver design should be accentuated. In this paper, we studied the effect of the different combination of codes, detection techniques, and the usage of single and multiple light emitting diodes (LEDs) in SAC-OCDMA system to highlight the main point that affect the most in reducing the BER as well as increasing the performance. We simulate the system performance of direct detection, AND subtraction detection, as well as modified-AND subtraction detection techniques with enhanced double weight (EDW) and modified double weight (MDW) codes via OptiSystem software. Simulation results show that the detection techniques significantly enrich the performance compared to the usage of diverse codes. Although the multiples LEDs give better performance than single LED in SAC-OCDMA system, the single LED still able to provide a good performance with less costly design than multiples LEDs.

An optimal cardinality of wavelength/time incoherent OCDMA system using 2-D hybrid FCC-MDW code

A 2-Dimensional (2-D) Wavelength/Time (W/T) scheme is proposed for spectral amplitude coding OCDMA network system. The new hybrid codes are utilizing Flexible Cross Correlation (FCC) and Modified Double Weight (MDW) codes which both codes have good correlation properties and capable to suppress multiple access interference (MAI). From the numerical calculation, it has been shown that this new hybrid code effectively suppresses the phase Induced Intensity Noise (PIIN) and eliminates MAI. Furthermore, the cardinality of this proposed code accommodates 150% and 275% improvement compared to 2-D PD code and 2-D M-Matrices code respectively at the BER=10-9. As a result, the performance of the system can be improved as well as support much more simultaneous users compared to Perfect Difference (PD) and M-matrices codes.

Encoder-decoder design for SAC-OCDMA using Flexible Cross Correlation (FCC) code algorithms

In this paper, we present an effective encoder-decoder design utilizing Flexible Cross Correlation (FCC) code for Spectral Amplitude Coding-Optical Code Division Multiple Access (SAC-OCDMA) systems. The FCC code has advantages, such as flexibility cross-correlation property for any given number of users and weights, as well as effectively reduces the impacts of Multiple-Access Interference (MAI). The proposed FCC SAC-OCDMA encoder-decoder had shown superior performance indicated FCC SAC-OCDMA encoder-decoder offers 100%,287% and 331% much larger number of active users compared to MDW K=60, MFH K=31 and Hadamard K=29, respectively.

Alleviation Noise Effect Using Flexible Cross Correlation Code in Spectral Amplitude Coding Optical Code Division Multiple Access Systems

A new code for Spectral Amplitude Coding - Optical Code Division Multiple Access (SAC-OCDMA) is proposed and is called Flexible Cross-correlation (FCC) code. The FCC code possesses various advantages; including easy code construction using Tridiagonal matrix compared to other SAC-OCDMA codes such as MDW, MQC and MFH, shorter code length and the important properties of this code is the flexible cross-correlation. Our results reveal that FCC code can effectively alleviated Phase Induced Intensity Noise (PIIN) and allows large cardinality and improve the bit error rate performance.