Mohamad Kadim Suaidi

A review of Genetic Algorithms and Parallel Genetic Algorithms on Graphics Processing Unit (GPU)

Genetic Algorithms (GAs) is proven to be effective in solving many optimization tasks. GAs is one of the optimization tools used widely in solving problems based on natural selection and genetics. This paper is intended to cover the study of GA and parallel GA and analyses its usage in CPU and GPU. One of the popular ways to speed up the processing time was by running them as parallel. The idea of parallel GAs may refer to an algorithm that works by dividing large problem into smaller tasks. Broad literature review in this paper includes a categorization of the GA operations that involved with some theories and techniques used in GA, presented with the aid of diagrams. This review attempts to study and analyse the behaviour of GA and parallel GA categories to work in GPU depending on the type of genetic algorithm. Parallel GA for GPU covers the architecture of Compute Unified Device Architecture (CUDA).

MIMO beamforming network having polarization diversity

This paper presents a MIMO channel measurement for indoor environment. The results present the comparison of channel capacity by using beamforming technique in MIMO systems. Also, polarization diversities (vertical and horizontal) are introduced to reduce multipath fading issues. The measurements were conducted at 2.4GHz with Line of Sight (LOS) scenario.

A meandered triple-band printed dipole antenna for RFID

In this paper, a meandered triple-band printed dipole antenna is proposed for Radio Frequency Identification (RFID). This meandered tri-band printed dipole antenna is designed to operate at 0.92 GHz, 2.45 GHz and 5.8 GHz with the aid of Computer Simulation Technology (CST) software. In order to achieve triple-band operation, the proposed antenna contains two branch elements, which act as an additional resonator. The designed antenna is fabricated using Taconic RF-35 substrate with a dielectric constant ( εr) of 3.5 and thickness (h) of 0.508 mm. The antennas parameters for triple-band operation are investigated and discussed. Then, this fabricated antenna is integrated with the UHF microchip to become a passive UHF tag. This tag is tested by measuring the reading distance and it is found that the proposed tag can be used for RFID application.

A smooth forwarding operation in wireless mesh network

The IEEE 802.11 Distributed Coordination Function (DCF) Medium Access Control (MAC) protocol is designed to efficiently facilitate the limited communication bandwidth of wireless channel. This protocol uses Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) mechanism. This mechanism continues suffer from throughput degradation when directly applied in multihop Wireless Mesh Network (WMN). The major reason for this poor performance is due to larger signaling overheads (RTS and CTS signaling packet) introduced in order to forward a single data packet in multihop WMN. This inefficient forwarding operation caused the throughput degradation signifficantly. Therefore, an efficient forwarding operation is proposed in this paper to reduce the amount of signaling overheads which are needed to forward a single packet in multihop WMN. The proposed protocol uses the capability of overhearing in order to forward the data packet from one hop to another hop. This process will continue until the data packet reaches the respective destination. As a result, the enhanced protocol reduces the latency caused by signaling thus improve its throughput in multihop WMN. The multihop network performances are evaluated analytically in terms of throughput and delay. Through the simulation, it is proven that the proposed protocol provides significant improvement in throughput and delay. The results show that the proposed protocol outperforms the existing IEEE DCF MAC protocol when it is evaluated in multihop WMN.

A triple-band dipole antenna with 0.92 GHz AMC-HIS

A triple-band dipole antenna integrated with 0.92 GHz Artificial Magnetic Conductor (AMC) is presented. The AMC structure is called a high-impedance surface (HIS) structure and is useful as a ground plane to the dipole antenna. This structure can be used to prevent the degradation of tag and antenna performance caused by the conductive materials (metal objects) and to increase the antenna gain. This paper begins by investigating the parameters in AMC design such as a patch and gap size. The AMC is characterized by the frequency where the phase of the reflection coefficient is zero degrees and has reflected wave in-phase with the incident wave.

Design and impedance modeling for dual band and multiple band frequency selective surface (FSS)

This paper presents a dual band and multiple band frequency selective surface (FSS) on energy saving glass (ESG). In this paper, there are two designs that have been presented, namely Design A which is a combination of double strip in vertical and horizontal position and Design B is a combination of double strip in vertical and horizontal position using complementary techniques. Design A and Design B are simulated using CST Microwave Studio software. The simulation process is based on the characteristics of the reflection coefficient (S11) and transmission coefficient (S21) of the FSS. The Design A resonates at two frequencies of 1.75 GHz and 3.4 GHz. The Design B resonates at three frequencies of 0.8 GHz, 1.8GHz and 3.4 GHz.

The investigation of single, dual and tri-band frequency selective surface

The single, dual and tri-band Frequency Selective Surface (FSS) design structure is designed and simulated by using CST Microwave Studio software. The reflection (S11) and transmission (S21) of the design FSS structure is analyzed based on the six types of configuration that have been set up. All configurations are simulated with the same size of the FSS design structure. The hybrid material (FR4 and glass) affects the transmission and reflection signals of the FSS which led to the compact structure. The measurement results are agreed for all FSS design structures but the difference is due to the transmission losses.

Performance evaluation of multiple differential detection for third generation mobile communication system

Third generation mobile communication system is widely used nowadays. One of its parameter standard, which is QPSK modulation has been adopted by International Telecommunication Union (ITU) to be used in IMT-2000. However, due to amplitude variations introduced in QPSK, a rather robust and reliable data modulation technique, namely the pi/4-shift Differential QPSK is proposed. For detection purposes, two types of detectors are evaluated for their performance in AWGN and Rayleigh fading channels. A differential detection technique called multiple differential detection technique which uses maximum-likelihood sequence estimation (MLSE) of the transmitted phases is compared with conventional differential detection which uses symbol-by-symbol detection. By using some of the IMT-2000 standard parameters, the simulation results show that multiple differential detection scheme performs much better than conventional differential detection scheme.

Fifth order versus third order intermodulation distortion

The third order intermodulation distortion (IMD₃) rather than the fifth order intermodulation distortion (IMD₅) is often considered when examining the performance of an analogue fibre optic system. This paper aims at looking into the possibility of the IMD₅ being comparable to the IMD₃. The IMD₅ generated when the laser is intensity-modulated by the multiple carriers signal is simulated and compared to the IMD₃. Individual IMD₅ level is found to be lower than the IMD₃ when the RF powers of the individual carriers are low or the modulation index per channel is low. However the composite IMD₅ level at channel position could exceed the composite IMD₃ especially when modulation index increases. This is contributed by the number of IMD₅ being greater than that of the IMD₃ based on counting. Hence indicating the IMD₅ should not be neglected in examining the performance of the analogue fibre optic system driven by multiple carriers.