COVID-19 Pandemic: Langkawi Vocational College Student Challenge in Using Google Classroom for Teaching and Learning (T&L)

The implementation of government-issued social awareness during the COVID-19 pandemic has affected the teaching and learning (T&L) activities. This study aims to identify the challenges that students face in using Google Classroom as a T&L method during the COVID-19 pandemic. A total of 39 Culinary Arts Diploma students at Langkawi Vocational College, Kedah who took the subjects of DHA1234 - Basic Food and Cookery, DHA 3051 - Final Year Project 1 and DHA 1123 - Introduction to Hospitality Industry participated in the study. The questionnaire used was adapted from the previous study and had received expert’s confirmation before being used in the study. The results of the study were analyzed using descriptive statistics involving average use, standard deviation, percentage, frequency, and score. Inferencial statistics involved pearson correlation tests. The study showed that the mean level of challenge faced by students in using Google Classroom is 3.46. Meanwhile, the pearson correlation test found that the significant value was .000. Therefore, there was a relationship between motivational and internet networks aspects. Therefore, the hypothesis (H0) stated in the hypothesis section was rejected

Modeling and characterization of urban radio channels for mobile communications

Results of this thesis contribute in modeling and characterization of radio channels for future mobile communications. The results are presented mainly in three parts: a) modeling of propagation mechanisms, b) methodology of developing a propagation model, c) characterization of urban radio channel. One of the main propagation physical phenomena that have an important role in diverting signals to non line of sight scenarios is the diffraction process. This thesis proposes diffraction coefficients that have better agreement with finite difference time domain solution and rigorous diffraction theory than the coefficient commonly used in propagation predictions for mobile communications. The importance of diffuse scattering has also been investigated and showed that this physical process may have a key role in urban propagation, with a particular impact on the delay spread and angular spread of the signal at the receiver. This thesis proposes wideband propagation models for main and perpendicular streets of urban street grids. The propagation models are ray-based and are given in explicit mathematical expressions. Each ray is characterized in terms of its amplitude, delay, and angle of arrival, angle of departure for vertical and horizontal polarizations. Each of these characteristics is given in a closed mathematical form. Having wideband propagation model in explicit expression makes its implementation easy and computation fast. Secondary source modeling approach for perpendicular streets has also been introduced in this thesis. The last part of the thesis deals with characterization of urban radio channels for extracting parameters that help in successful design of mobile communication systems. Knowledge of channel characteristics enables reaching optimum trade off between system performance and complexity. This thesis analyzes measurement results at 2 GHz to extract channel parameters in terms of Rake finger characteristics in order to get information that helps to optimize Rake receiver design for enhanced-IMT2000 systems. Finger life distance has also been investigated for both micro- and small cell scenarios. This part of the thesis also presents orthogonality factor of radio channel for W-CDMA downlink at different bandwidths. Characterization of dispersion metrics in delay and angular domains for microcellular channels is also presented at different base station antenna heights. A measure of (dis-) similarity between multipath components in terms of separation distance in delay and angular domains is introduced by the concept of distance function, which is a step toward in development of algorithm extraction and analysis multipath clustering. In summary, the significant contributions of the thesis are in three parts. 1) Development of new diffraction coefficients and corrections of limitations of existing one for accurate propagation predictions for mobile communications. 2) Development of wideband propagation models for urban street grid. The novelty of the model is the development in explicit mathematical expressions. The developed models can be used to study propagation problem in microcellular urban street grids. 3) Presenting channel parameters that will help in the design of future mobile communication systems (enhanced-IMT2000), like number of active fingers, finger life distance, and orthogonality factors for different bandwidths. In addition, a technique based on multipath separation distance is proposed as a step toward in development of algorithms for extraction and analysis of multipath clusters.reviewe

Multicarrier CDMA: A very promissing multiple access scheme for future wideband wireless networks

International audienceIn this paper, multicarrier techniques are studied in the context of the future wideband wireless networks. After a brief presentation of the third generation mobile networks, MC-CDMA systems are considered for the downlink of the future high rate cellular networks. The performance of different mono-user and multi-user detection techniques are compared with the help of Monte Carlo simulations over a frequency selective Rayleigh channel. Thus, the efficiency of MC-CDMA as a very promising multiple access and robust modulation scheme is successfully demonstrated for the downlink of the future wideband mobile networks. Finally, the first results concerning the performance of Multicarrier CDMA technique combined with space-time block coding in order to build a Multiple Input Multiple Output/MC-CDMA system are presented over a Rayleigh channel

An Overview on Evolution of Mobile Wireless Communication Networks: 1G-6G

There has been a huge advancement in mobile wireless communication since the last few decades. This advancement consist of several generations and is still going on. The journey of mobile wireless communication began with 1G followed by 2G,3G,4G,and under research future generations 5G,6G,7G. In this paper an attempt has been made to provide an overview of evolution of mobile generations by comparing the challenges and features that have evolved from each generation and explaining how improvements have been made from earlier generation to the next one. DOI: 10.17762/ijritcc2321-8169.150513

Mobile IP

The Internet is growing exponentially, both in the amount of traffic carried, and in the amount of hosts connected. IP technology is becoming more and more important, in company networks (Intranets), and also in the core networks for the next generation mobile networks. Further, wireless access to IP networks is becoming mature (e.g., IEEE 802.11 networks, Irda, Bluetooth). At the same time, the existing generation of mobile (cellular) networks is evolving from voice services to networks with a rich mixture of services (e.g., GPRS and 3rd generation networks). These developments demand for mobility in IP-based networks. A first solution to this problem has been proposed as Mobile IP. This solution makes use of Home Agents and Foreign Agents to allow mobile hosts to move freely between subnetworks while communicating.\ud \ud The tutorial will describe and explain the approaches taken to provide mobility for hosts in the Internet and IP-based networks. The tutorial will start with expanding on the need for Mobile IP. It will briefly explain the main Internet principles relevant to Mobile IP. The problems Mobile IP is trying to solve will be explained. After an overview of the general operation of Mobile IP, the principal mechanisms will be discussed in more detail. The tutorial will describe the operation of advertising care-of addresses, mobile host registration, tunneling, and proxy- and gratuitous ARP. Special attention will be paid to the main problems related to Mobile IP, such as triangle routing and smooth hand-off. The tutorial will finally explain how mobility can be supported in IPv6.\u

U-Shaped Microstrip Patch Antenna for WLAN/WIMAX Applications

A full-duplex radio design communication systems design based on the WiMax/WLAN antenna. The design an antenna in this report presented a triple-band operation with significant impedance bandwidth for WLAN/WiMAX system. The designed antenna having the compact size of 10 x 26 mm2 and shaped of antenna is U-shaped. The overall performance of the antenna three different bands 1) band-1:- 2.40 to 2.53 GHz, 2) band-2:-3.40 o 3.60 GHz and 3) band-3:- 5.00 to 6.00 GHz, these bands cover the WiMAX (2.5, 3.5, 5.5) and WLAN (2.4, 5.2, 5.8) bands. Here HFSS simulator used to simulate and validate the results. By combining the performance of complete WLAN/WiMAX antenna with MIMO antenna, the proposed MIMO antenna with wide operating frequencies 2.4 GHz. Thus the simulation results along with the given parameter values show that the antenna can simultaneously operate over WLAN, WiMAX and MIMO frequency bands

Wavelet-based multi-carrier code division multiple access systems

EThOS - Electronic Theses Online ServiceGBUnited Kingdo