Norsuzila Ya'acob

E-shape microstrip patch antenna for wideband applications

This paper presents the design of E-shaped microstrip single patch antenna with wideband operating frequency for wireless application. The antenna design is an improvement from previous research and it is simulated using CST Microwave Studio 2009 software. Parametric study was included to determine affect of design towards the antenna performance. The performance of the designed antenna was analyzed in term of bandwidth, gain, return loss, VSWR, and radiation pattern. The design was optimized to meet the best possible result. Substrate used was C-Foam PF-2 which has a similar dielectric constant of air. The results show the wideband antenna is able to operate from 8.34 GHz to 13.86 GHz frequency band with optimum frequency at 8.73 GHz.

A review on classification of satellite image using Artificial Neural Network (ANN)

Artificial Neural Networks (ANNs) have been useful for decades to the development of image classification algorithms applied to several different fields. Image classification is the major component of the remote sensing to extract some of the important spatially variable parameters, such as land cover and land use (LCLU). The aim of this study is to investigate the capability of Artificial Neural Network system (ANNs) for classifying the satellite images using different algorithm which are back-propagation algorithm and K-means algorithm with different approaches. ANNs classifier is compared with two classification techniques of conventional classifier which are Maximum Likelihood (ML) and unsupervised (ISODATA). Neural network classification is based on the training data set and it the proper classification. ML and ISODATA classifiers are broadly used in many remote sensing applications. Overall classification accuracy and Kappa Coefficient were calculated to get the comparison of the performance the image classification. The optimal performance would be identified by validating the classification results with ground truth data. The accurate classification can produce the correct LU/LC map that can be used fir variety.

Design of wideband microstrip patch antenna using L-probe fed at 2.6 GHz

This paper proposes the design of wideband microstrip patch antenna using L-probe fed. The structure consist of air-filled substrate with dielectric permittivity, ε0 and thickness, h0 which is sandwiched between superstrate and a ground plane. The design is constructed with respect to 2.6 GHz of centre frequency. Parametric study were performed to analyze the effects of the design towards antennas performance. An accomplishment of the design has been carried out using CST Microwave Studio software. Simulation has been performed and results clearly showed the capability and potential of the antenna design itself. The utilization of Lprobe fed as well as parasitic elements provide bandwidth enhancement, while the use of parallel slots offers patch size reduction and gain enhancement. To conclude, antennas performance was analyzed in terms of bandwidth, gain, VSWR and radiation pattern. The simulated impedance bandwidth of 11.04% ranging from 2.444 Ghz to 2.729 Ghz is achieved at 10 dB return loss with VSWR<;2.

Ionospheric mapping function for total electron content (TEC) using global positioning system (GPS) data in Malaysia

The ionosphere layer is very important to the communication system. This research involves the determination of total electron content (TEC) in ionosphere based on height in order to determine the appropriate TEC value for Malaysia and for the equitorial region generally. The ionospheric model used is the single layer model based on the Bernese GPS 5.0 Software. The ionosphere TEC map of Malaysia is produced by using the single layer model which can be found in Bernese GPS 5.0 Software. Results show that the ionospheric variation especially the TEC values are different relative to the height studied. The appropriate TEC value for Malaysia is at the height 450 km and the maximun TEC value is at the height of 150 km. These variations play an important role in understanding the TEC nature in ionosphere and thus will simplify the studies about phenomenon happen in ionosphere especially in Malaysia.

Performance Analysis of Handover Strategy in Femtocell Network

Femtocells, as known as HeNB is the tremendous network technology in the Long Term Evolution (LTE) network in order to fulfill the upcoming demand of high data rates. However, Femtocells deployment may cause the incidence of frequent and unnecessary handover due to the movement of the user. As Femtocells coverage area is very small and deployed randomly, there are many possible targets Femtocells for handover. This paper analyzed on the performance analysis of handover strategy in Femtocells network under Hybrid Access Mode to minimize the unnecessary handover. The handover strategy for three different threshold stay time with considering the velocity of user equipment (UE) in the mobility are analyzed. The simulation results showed that the proposed algorithm minimized the number of handover and decreased the unnecessary handover probability. Simulation results indicate that the proposed algorithm has a better performance as compare with the traditional strategy

Handover mechanism in dynamic load balancing for LTE systems

Next-generation wireless systems will be conceived to have all Internet Protocol (IP). It is based on infrastructure with the support of heterogeneous access technologies. IP system is the designs of intelligent mobility management technology that have many advantages to achieve global roaming as compare to others technologies. As the user allowed to move freely across different network, the hotspot cells can occur when available wireless resources at some point of location are not sufficient to sustain the needs of users. Therefore, this scenario can potentially leads to high dropped calls rate, which can deteriorate the service quality of users. This paper presents a load balancing scheme that can control the handover time based on the load status of cells. The scheme requests the load information of the target cell in advance to avoid handover to an overloaded target cell. The simulation results show a significant reduction in dropped calls rate which can manage overloaded traffic in the system.

Handover initiation across heterogeneous access networks for Next Generation Cellular Network

The heterogeneous networks are expected to become a main focus in the development toward the Next Generation Cellular Network (NGCN). The heterogeneous networks will allow users to move freely across different networks. However, the determination of the handoff initiation time is difficult in heterogeneous networks since many factors should be considered in the decision algorithm. Therefore, in this research, the main idea is early detection of the possibility of inter access system handoff and then to carry out registration of the mobile in the next domain before the actual handoff. In this paper, first the mathematical formulation for the length of the dynamic boundary area is derived as a function of users speed. Then, an adaptive value of Receive Signal Strength (RSS) threshold is proposed using the estimation of the boundary area to enable the mobile handoffs on time. Numerical analysis is done to evaluate the performance of the handoff initiation using the above mathematical formulations. By incorporating value of speed and handoff signaling delay into adaptive RSS calculation in advance, the system can make better preparation for the handoff so that the mobile handoffs on time.

Earthquake prediction technique based on GPS dual frequency system in equatorial region

The ionospheric Total Electron Content (TEC) measurements were investigated at Universiti Teknologi Malaysia, UTMJ on 20 February - 20 March 2007. The observation was made 14 days before earthquake and 14 days after earthquake. TEC is extracted using GPS dual frequency data which in RINEX format that supplied by JUPEM (Jabatan Ukur dan Pemetaaan Malaysia). In order to reveal possible earthquake precursor through the changes variation of TEC reading, Southern Sumatra Indonesia earthquake that happened on 6th March 2007 is chosen as a study case. The results show that satellite facilities may detect earthquake precursors in ionosphere 5-11 days or a few hours before main shock and various grounds based or satellite observation have shown strong perturbation of the ionosphere after earthquake. The results show a good agreement with other researchers who studied other earthquakes.

Differences of image classification techniques for land use and land cover classification

Land use and land cover classification of remotely sensed data is an important research and commonly used in remote sensing application. In this study, the different types of classification techniques were used by using satellite image of some part of Selangor, Malaysia. For this objective, the land use and land cover was classified with Landsat 8 satellite image and ERDAS Imagine software as the image processing packages. From the classification output, the accuracy assessment and kappa statistic were evaluated to get the most accurate classifier. The optimal performance would be identified by validating the classification results with ground truth data. Of classified image, the Maximum Likelihood technique (overall accuracy 82.5%) is the highest and more applicable for satellite image classification compared with Mahalanobis Distance and Minimum Distance. The accurate classification can produce the correct Land Use and Land Cover map that can be used for many varieties purposes.

Reduction of ISI using different equalization of adaptive algorithm for mobile WiMAX communication system

Orthogonal frequency division multiple access (OFDMA) is one of the modulation technique designed to have high speed data rate transmission in wireless communication system. Inter symbol interference (ISI) is a main cause that can reduce efficiency of the system due to multipath propagation. Different equalization of adaptive algorithm technique had been proposed in this research in order to reduce ISI in OFDMA system. This research also proved the combination of space time frequency block code (STFBC) with multiple input multiple output (MIMO) antenna enable to overcome ISI by using IEEE 802.16 simulation parameter. The simulation results show the improvement of bit error rate (BER) performance after reducing ISI and also prove that STFBC was able to achieve maximum diversity order in the MIMO OFDMA system.