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Many FSO communication systems are using a conventional technique that is OOK technique in the system. Some enhancement of technique is explained in this paper to decrease the error rate that occurs in the system. The comparison between OOK technique and DDM technique is investigated in order to compare the error rate and power received. The result shows that the performance of DDM technique generates...
This paper demonstrates the effect of haze condition on free space optical (FSO) communication and to thin out the attenuation effects. The effects in the main focus on the atmospheric attenuation effects due the visibility and link range (length). Visibility is the main concern in utilizing the FSO communication system. The higher visibility, the longer transmission link. Hence, FSO performance could...
This paper develops new coding technique to generate multiplexed patterns for Duty-Cycle Division Multiplexing (DCDM) which allows users to share the single transmission medium by assigning different duty cycles for each user. This coding technique aims to reduce the amount of noise which is added due to multilevel signalling. Single channel back-to-back optical fibre system is designed based on the...
This paper organizes the performance of twodimensional (2-D) Modified Double Weight (MDW) code for Optical Code Division Multiple Access (OCDMA) system by employing Avalanche Photodiodes (APD) as a gain. To accomplish the perfection system capacity, their cardinality, bit error rates (BER) and noise interferences are analyzed. With 2-D MDW with APD able to recovered the cardinality at least 61%, which...
Free Space Optical communication system is a technology that solves the problem of network connectivity. In this system, it contains a coding and technique to control the data that transferred using a laser beam from transmitter station through the atmosphere to receiver station. This technique is to optimize the error rate and improve the signal received. In this paper, the comparison between conventional...
This paper presents an improvement design of an Optical Code Division Multiple Access for Radio over Fiber (OCDMA-RoF) system. This improved system is divided into two main subsystems, Central Stations (CS) and Base Station (BS). Implement OCDMA code into RoF system promised a secure, cost-effective, and high-capacity mobile and multimedia wireless services. The analysis was made based on the relationship...
In this paper, we will focus on the modulation format used to produce the optical pulses, which are return to zero (RZ), and non-return to zero (NRZ). Bit error rate (BER) performance is assessed for OCDMA-RoF system. OCDMA-RoF system is viewed as a promising method for improving spectral efficiency and in the meantime diminish hardware equipment. The execution of RZ against NRZ is looked at through...
Research in optical communications is always determined by fundamentals for high information rates and enhanced spectral efficiency. Also, the development of highrequest modulation formats is included a higher bit rates per channel, which requirement expanded signal-to-noise ratio considerably and high power per channel. Then again, higher spectral efficiency also needs closely spaced channels to...
In this paper, an indoor optical wireless CDMA system based on zero cross correlation (ZCC) code is investigated under the influence of ambient light noise. We consider line of sight communication links between multiple emitters and receivers. We first establish an analytical expression of bit error rate and then validate its estimations with the simulated results. The finding results show a great...
This paper analyses the spectral efficiency of hybrid subcarrier multiplexed (SCM) Optical Code Division Multiple Access (OCDMA) and conventional OCDMA based on AND Subtraction technique. We compared the spectral efficiency of SCM and the conventional OCDMA with respect the number of weights and number of users. Results indicate that the SCM OCDMA is more efficient compared to conventional OCDMA.
This paper presents the link budget analysis for free space optical (FSO) communication and the studies on how to reduce the attenuation effect to improve FSO link. The effects are primarily focused on the atmospheric attenuation on the received power. Transmission power is the main priority in link budget. The power used to transmit data is gradually decreased along the path due to attenuation effects...
High speed transmission is the most important thing that needed in free space optical (FSO) communication. It can send and receive data speedily. However FSO have interference during transmission. Usually strong turbulence is the main interference affected in FSO. This paper focuses on increase the high speed transmission in FSO communication by using new dual diffuser modulation (DDM) technique under...
Free space optical (FSO) communication is becoming a mainstream technology that plays a major role in application network. This system contains a techniques to reduce the probability of error. This paper focus on the performance Zero-Cross Correlation (ZCC) code of Optical Code Division Multiple Access (OCDMA) operation in FSO system. This paper also discuss about the comparison between ZCC code and...
A detailed of code construction for an Optical Code Division Multiple Access (OCDMA) system with flexible cross correlation is presented to reduce the effect of interference thus optimizing the code length. In this paper, the proposed code called Flexible Cross Correlation (FCC) code. The FCC code can be constructed using a simple tridiagonal matrix compared to other OCDMA codes such as MDW and DCS...
The benefits of employing 2-Dimensional (2D) Wave-length/Time (W/T) Hybrid code to mitigate the optical noise in spectral amplitude coding OCDMA networks system is in-vestigated. This analysis allows us to identify the influences of optical noise such as PIIN noise, shot noise and thermal noise in the system performance by using 2D Hybrid FCC-MDW code. The mathematical calculation reveals this new...
This paper analyzes the performance of the OS-CDMA system using OFDM technique to enhance the channel data rate, to save power and increase the number of user of OSCDMA systems. This system compared with previous hybrid subcarrier multiplexing/optical spectrum code division multiple-access (SCM/OSCDMA) system. The average received SNR with the nonlinearity of subcarriers is derived. The theoretical...
A new class of code called Flexible Cross-Correlation (FCC) for Spectral-Amplitude Coding Optical Code-Division Multiple-Access (SAC-OCDMA) systems has been de-veloped. 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 impact of Phase-Induced Intensity Noise (PIIN) and Multiple-Access Interference (MAI)...
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...
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)....
Optical Code Division Multiple Access (OCDMA) system are limited by the interference between users as well code length due to the code developments. A detailed of code construction for a OCDMA system with flexible cross correlation is presented to reduce the effect of interference thus optimizing the code length. In this paper, the proposed code called Flexible Cross Correlation (FCC) code. The FCC...
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