Rashid A. Fayadh

Development of a New Approach for High-Quality Quadrupling Frequency Optical Millimeter-Wave Signal Generation Without Optical Filter

In this paper, we propose a new approach to generate quadrupling-frequency optical millimeter-wave (mm-wave) signal with carrier suppression by using two parallel Mach-Zehnder modulators (MZMs) in Radio-over-flber (RoF) system. Among the numerous properties of this approach, the most important is that a fllterless optical mm-wave at 60GHz with an optical sideband suppression ratio (OSSR) as high as 40dB can be obtained when the extinction ratio of the MZM is 25dB. Simplicity and cost-efiectiveness have made this approach a compelling candidate for future wave-division-multiplexing RoF systems. Theoretical analysis is conducted to suppress the undesired optical sidebands for the high-quality generation of frequency quadrupling mm-wave signal. The simulation results show that a 60GHz mm-wave is generated from a 15GHz radio frequency (RF) oscillator with an OSSR as high as 40dB and an radio frequency spurious suppression ratio (RFSSR) exceeding 35dB without any optical or electrical fllter when the extinction ratio of the MZM is 25dB. Furthermore, the efiect of the non-ideal RF-driven voltage as well as the phase difierence of RF-driven signals applied to the two MZMs on OSSR and RFSSR is discussed and analyzed. Finally, we

Enhancing link quality in a multi-hop relay in LTE-A employing directional antenna

This paper proposes a new approach for enhancing link quality between relay node (RN) and base station (BS). Two types of antennas were proposed at the relay, the first type is the directional antenna, which is directed toward the base station to improve the relay link quality, thereby reducing outage probability by increasing relay link capacity. The second type is the omni-directional antenna, which is used for the exchange of information between the RN and attached users. An improvement of 32% in capacity and 25% in received signal strength at the relay link has been observed. An ATDI simulator, which handles the digital cartography for the first tier of interference in urban areas, verified the numerical results.

REDUCING TRANSMITTED POWER OF MOVING RELAY NODE IN LONG-TERM EVOLUTION-ADVANCED CELLULAR NETWORKS

Wireless multi-hop relay networks have become very significant technologies in mobile communications. These networks ensure data rate transfer and covera ge extension with a low cost. In this study two typ es of relay are studied; Fixed Relay Node (FRN) and Moving Relay Node (MRN). Where system analyses for uplink and downlink transmission are derived in thi s study. Moreover the optimal relay location of FRN was proposed to provide a maximum achievable rate at user in cell edge region. Finally, a new algorith m was suggested to balance and control on the transmi tted power of MRN over cell size to provide the required SNR and throughput at the users inside veh icle with reducing the consumption transmitted rela y power. Numerical results indicate an enhancement in received signal strength for users at the cell edg e from (-90 to -65) dBm and 40% increment from all cell size after de ploying FRN at proposed locations. As well as, the results revealed that there is saving nearl y 75% from transmitted power in MRN after using proposed algorithm. ATDI simulator was used to verify the nu merical results, which deals with real digital cartographic and standard formats for terrain.

Finger-shaped antenna design for ultra-wideband applications

In recent years, the UWB technology in wireless communication systems is required for many military, civilian, and medical applications, so small and economic UWB antennas need to be produced for these purposes. Since the Federal Communications Commission (FCC) reported the UWB frequency of 7.5 GHz (from 3.1 GHz to 10.6 GHz) was licensed for high data rate wireless technology and antenna plays a very role in UWB systems. The design, simulation, and fabrication of finger-shaped antenna are presented in this paper. The designed antenna has a reflection coefficient (S11) less than -10 dB and voltage standing wave ratio (VSWR) less than 2 for the frequency of 4 to 12 GHz. The far field radiation patterns are introduced with the proposed antenna dimensions and feeding by microstrip transmission line feeder. Simulation and fabrication results for S11 VSWR, radiation patterns, and gain of the proposed antenna are presented and discussed along the frequency band 4 to 12 GHz.

Design of ultra wideband rectangular microstrip notched patch antenna

The UWB is 7.5 GHz (from 3.1 GHz to 10.6 GHz) was defined by Federal Communications Commission (FCC) for high data rate wireless communication systems. This band needs special and active antenna for transmission and reception of wideband signals. So that, the design of UWB antenna plays very important role in indoor and outdoor wireless systems. Because of more challenges toward the wireless communication, i.e., inter-symbol interference, multi-access interference, and narrow band system interference, the UWB antenna should have the capability of operation during these challenges. The notched microstrip patch antenna was designed using CST microwave studio with limited dimensions and the results are accepted for the UWB that was allocated by FCC. The proposed antenna was fabricated on printed circuit board (PCB) with same dimensions and analysis. Taconic TLY-5 substrate material was used in this small size antenna to give low cost and lighter than those made of FR4 substrate material. The measured results are nearly identical with those of simulation for return loss (S11) and voltage standing wave ratio (VSWR). The simulated radiation patterns are nearly omni-directional radiations over the UWB bandwidth.

Two Small Antenna Designs for Ultra-Wideband Wireless Systems

This chapter focuses on designing small antennas used by Ultra Wideband (UWB) wireless systems. The study has been taken from the conventional rectangular manuscript patch antenna to miniaturize the size of used antenna to be more suitable for future 5G system applications. These applications are dealing with high data transmission rates over a very large spread spectrum frequency (3.1–10.6 GHz), so that, many challenges are provided in the antenna design. The main objective of this research is to design, and analyze two small manuscript patch antennas to satisfy UWB technology requirements. Several techniques were used to optimize the UWB bandwidth performance such as radiator dimensions, planar ground plane, and unprinted gaps between ground plane and radiators. Therefore, this work introduces two designs of microstrip-fed, small, and low profile which are called ax-shaped and socket-shaped patch antennas. It has been demonstrated numerically that the proposed antennas are suitable for UWB systems. They can provide satisfactory frequency domain performance (less than −10 dB return loss), including ultra-wide bandwidth with nearly omni-directional radiation patterns, and relatively good current density over the radiator parts of the proposed antenna designs.

Analyzing mobile WiMAX base station deployment under different frequency planning strategies

The frequency spectrum is a precious resource and scarce in the communication markets. Therefore, different techniques are adopted to utilize the available spectrum in deploying WiMAX base stations (BS) in cellular networks. In this paper several types of frequency planning techniques are illustrated, and a comprehensive comparative study between conventional frequency reuse of 1 (FR of 1) and fractional frequency reuse (FFR) is presented. These techniques are widely used in network deployment, because they employ universal frequency (using all the available bandwidth) in their base station installation/configuration within network system. This paper presents a network model of 19 base stations in order to be employed in the comparison of the aforesaid frequency planning techniques. Users are randomly distributed within base stations, users’ resource mapping and their burst profile selection are based on the measured signal to interference plus-noise ratio (SINR). Simulation results reveal that the FFR has advantages over the conventional FR of 1 in various metrics. 98 % of downlink resources (slots) are exploited when FFR is applied, whilst it is 81 % at FR of 1. Data rate of FFR has been increased to 10.6 Mbps, while it is 7.98 Mbps at FR of 1. The spectral efficiency is better enhanced (1.072 bps/Hz) at FR of 1 than FFR (0.808 bps/Hz), since FR of 1 exploits all the Bandwidth. The subcarrier efficiency shows how many data bits that can be carried by subcarriers under different frequency planning techniques, the system can carry more data bits under FFR (2.40 bit/subcarrier) than FR of 1 (1.998 bit/subcarrier). This study confirms that FFR can perform better than conventional frequency planning (FR of 1) which made it a strong candidate for WiMAX BS deployment in cellular networks.The frequency spectrum is a precious resource and scarce in the communication markets. Therefore, different techniques are adopted to utilize the available spectrum in deploying WiMAX base stations (BS) in cellular networks. In this paper several types of frequency planning techniques are illustrated, and a comprehensive comparative study between conventional frequency reuse of 1 (FR of 1) and fractional frequency reuse (FFR) is presented. These techniques are widely used in network deployment, because they employ universal frequency (using all the available bandwidth) in their base station installation/configuration within network system. This paper presents a network model of 19 base stations in order to be employed in the comparison of the aforesaid frequency planning techniques. Users are randomly distributed within base stations, users’ resource mapping and their burst profile selection are based on the measured signal to interference plus-noise ratio (SINR). Simulation results reveal that the FFR ha...

Performance enhancement of rake-receiver using continuous and discrete wavelet transforms analysis through NLOS propagation

In this paper, three levels of analysis and synthesis filter banks were used to create coefficients for a continuous wavelet transform (CWT) and discrete wavelet transform (DWT). The main property of these wavelet transform schemes is their ability to construct the transmitted signal across a log-normal fading channel over additive white Gaussian noise (AWGN). Wireless rake-receiver structure was chosen as a major application to reduce the inter-symbol interference (ISI) and to minimize the noise. In this work, a new scheme of rake receiver is proposed to receive indoor, multi-path components (MPCs) for ultra-wideband (UWB) wireless communication systems. Rake receivers consist of a continuous wavelet rake (CW-rake) and a discrete wavelet rake (DW-rake), and they use huge bandwidth (7.5 GHz), as reported by the Federal Communications Commission (FCC). The indoor channel models chose for analysis in this research were the non line-of-sight (LOS) channel model (CM4 from 4 to 10 meters) to show the behavior ...

Performance analysis of a finite radon transform in OFDM system under different channel models

In this paper, a class of discrete Radon transforms namely Finite Radon Transform (FRAT) was proposed as a modulation technique in the realization of Orthogonal Frequency Division Multiplexing (OFDM). The proposed FRAT operates as a data mapper in the OFDM transceiver instead of the conventional phase shift mapping and quadrature amplitude mapping that are usually used with the standard OFDM based on Fast Fourier Transform (FFT), by the way that ensure increasing the orthogonality of the system. The Fourier domain approach was found here to be the more suitable way for obtaining the forward and inverse FRAT. This structure resulted in a more suitable realization of conventional FFT- OFDM. It was shown that this application increases the orthogonality significantly in this case due to the use of Inverse Fast Fourier Transform (IFFT) twice, namely, in the data mapping and in the sub-carrier modulation also due to the use of an efficient algorithm in determining the FRAT coefficients called the optimal order...

Wireless rake-receiver using adaptive filter with a family of partial update algorithms in noise cancellation applications

For high data rate propagation in wireless ultra-wideband (UWB) communication systems, the inter-symbol interference (ISI), multiple-access interference (MAI), and multiple-users interference (MUI) are influencing the performance of the wireless systems. In this paper, the rake-receiver was presented with the spread signal by direct sequence spread spectrum (DS-SS) technique. The adaptive rake-receiver structure was shown with adjusting the receiver tap weights using least mean squares (LMS), normalized least mean squares (NLMS), and affine projection algorithms (APA) to support the weak signals by noise cancellation and mitigate the interferences. To minimize the data convergence speed and to reduce the computational complexity by the previous algorithms, a well-known approach of partial-updates (PU) adaptive filters were employed with algorithms, such as sequential-partial, periodic-partial, M-max-partial, and selective-partial updates (SPU) in the proposed system. The simulation results of bit error ra...