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This paper provides details on the design of a beam steerable array antenna for mobile applications at 28 GHz frequency band. The array is designed using a Rogers RT/duroid 5880 substrate material of 0.254 mm thickness and dielectric constant of 2.2. The designed antenna is fed by a 2 × 2 Butler matrix (BM) which also serve as a beam former to obtain the beam scanning of from −16 to 16 degrees. The...
In this paper, a new two-code keying approach to enable bipolar encoding in high-rate spectral-amplitude-coding optical code-division multiple-access (SAC-OCDMA) systems is suggested. The analytical expressions are developed for the signal-to-noise ratio (SNR) and bit-error rate (BER) of SAC-OCDMA system based on the recommended approach using multi-diagonal (MD) code. The results indicate that the...
The capacity enhancement promised by switched beam smart antenna is a function of efficient selection of the active beam at each point in time. This article presents the use of artificial neural network (ANN) to improve the performance of switched beam smart antenna. The proposed method is based on feed forward backpropagation ANN. In this design, samples of the calibration of the footprint of the...
In this research, we present a novel encoding and decoding structure based upon two-code keying for high-rate spectral-amplitude-coding optical code-division multiple-access (SAC-OCDMA) systems. The OptiSystem (version 13) simulation software is used to measure the bit-error rate (BER) performance for different fiber lengths. The results indicate that the proposed coding structure clearly provides...
This paper presents a central base station (CBS) for radio over fiber (RoF) downlink system at 2.4 GHz. CBS is designed to replace the function of switching room in complex signal processing, which offers conversion and distribution at low cost, simple, and efficient system. The received optical signal at CBS from internet service provider (ISP) propagates through fiber cable to radio frequency (RF)...
An elegant encoding/decoding architecture based on two-code keying scheme for high-rate transmission in non-coherent spectral-amplitude-coding optical code-division multiple-access (SAC-OCDMA) systems, is suggested. To evaluate the performance improvement, a commercial OptiSystem software (Version 12.2.1) is used. The simulation results show that SAC-OCDMA system using the proposed architecture exhibited...
Security becomes the critical issue in incoherent spectral amplitude coding optical code division multiple access (SAC-OCDMA) systems. In preventing the unintended users from decoding and extracting the data due to the cross-correlation among code sequences, an ideal detection technique is needed to enhance the security of the SAC-OCDMA systems. In this paper, we study the efficiency of the modified-AND...
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...
In order to meet the ultra-high speed and ultra-long haul transmission distance in spectral amplitude coding optical code division multiple access (SAC-OCDMA) system, the dispersion impairment affecting the overall system performance should be minimized. In this paper, the transmission performance of SAC-OCDMA system is investigated based on single photodiode detection technique when a conventional...
Non-return-to-zero (NRZ) and return-to-zero (RZ) are two basic data formats in optical communication systems. In this paper, we compare the performance of NRZ against RZ with both AND as well as modified-AND subtraction detection techniques in spectral-amplitude coding optical code-division multiple-access (SAC-OCDMA) systems. Modified double-weight (MDW) codes are used as the signature codes for...
This paper examines the avalanche photodiode (APD) gain impact on spectral-amplitude coding optical code-division multiple-access (SAC-OCDMA) systems based single photodiode detection (SPD) technique. Numerical results are used for inspecting the APD gain influence upon the probability density function (PDF) and signal-to-noise ratio (SNR) performance. The usage of APD over positive-intrinsic-negative...
Progress in fiber optic technology have made long-haul communications systems reach distance that were once unheard of. This distance is made possible by using modulation techniques that do not require a complex link design which best applied in spectral-amplitude coding optical code-division multiple access (SAC-OCDMA) system. In this paper, we investigate the use of different detection schemes namely...
Free space optic (FSO) is considered as an attractive option to fiber optic. FSO has the capability to go beyond the limits of fiber optics. However, atmospheric turbulence causes fluctuations in the intensity of the received light signal, impairing link performance. In this paper, we describe a new technique to mitigate turbulence-induced intensity fluctuations, i.e., signal fading (under the effects...
The development of many high bit-rate multimedia applications has emphasized the demand for service differentiation or prioritization techniques to ensure end-user quality-of-service (QoS) necessities. This paper focuses on utilizing different detection schemes in spectral-amplitude coding optical code-division multiple-access (SAC-OCDMA) systems to support ‘triple-play’ services (voice, video, and...
The rapid progress in video-based Internet applications is increasing the demand for efficient optical communication systems. In this paper, developed detection technique for incoherent spectral-amplitude coding optical code-division multiple-access (SAC-OCDMA) systems is presented. In order to tighten the correspondence between practical and theoretical results, the most dominant noises that might...
Technology is already on the move towards exploiting the limits of the fiber's physical properties and more sophisticated techniques will be needed to increase the throughput and counteract the transmission impairments. In this paper, we present a new detection technique called the modified-AND subtraction detection for spectral-amplitude coding optical code-division multiple access (SAC-OCDMA) systems...
In this paper, we have evaluated the performance of spectral amplitude coding optical code-division multiple-access (SAC-OCDMA) systems. A performance comparison has been made between various OCDMA signature sequences (random diagonal (RD), modified double weight (MDW), and modified quadratic congruence (MQC) codes). Analytical expressions have been used to analyze the bit-error rate (BER) value for...
We compare the spectral efficiency of unipolar and bipolar encoding for spectral-amplitude coding optical code-division multiple access (SAC-OCDMA) systems operating with incoherent sources considering the intensity noise as the primary noise source. For both encoding techniques, the spectral efficiency of four SAC codes such as Hadamard, modified quadratic congruence (MQC), balanced incomplete block...
In this paper, we evaluate the spectral efficiency of unipolar spectral-amplitude coding optical code-division multiple access (SAC-OCDMA) system operating with incoherent sources in the present of intensity, shot, and receiver thermal noises. The spectral efficiency achievable by four SAC codes such as Hadamard, modified quadratic congruence (MQC), balanced incomplete block design (BIBD) and zero...
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