Decoding of Decode and Forward (DF) Relay Protocol using Min-Sum Based Low Density Parity Check (LDPC) System

Decoding high complexity is a major issue to design a decode and forward (DF) relay protocol. Thus, the establishment of low complexity decoding system would beneficial to assist decode and forward relay protocol. This paper reviews existing methods for the min-sum based LDPC decoding system as the low complexity decoding system. Reference lists of chosen articles were further reviewed for associated publications. This paper introduces comprehensive system model representing and describing the methods developed for LDPC based for DF relay protocol. It is consists of a number of components: (1) encoder and modulation at the source node, (2) demodulation, decoding, encoding and modulation at relay node, and (3) demodulation and decoding at the destination node. This paper also proposes a new taxonomy for min-sum based LDPC decoding techniques, highlights some of the most important components such as data used, result performances and profiles the Variable and Check Node (VCN) operation methods that have the potential to be used in DF relay protocol. Min-sum based LDPC decoding methods have the potential to provide an objective measure the best tradeoff between low complexities decoding process and the decoding error performance, and emerge as a cost-effective solution for practical application

TCP Performance Analysis in Dynamic GPRS LA

This paper presents the findings on TCP performance measurements in the LA process during the deployment of GPRS CS1 and CS2 coding schemes and after the activation of two more coding schemes, CS3 and CS4. The measurements are done under various network scenarios based on users’ physical locations in one of Malaysia’s commercially deployed live GPRS networks. End-to-end evaluation of FTP application is used for the assessment together with tracing at the GPRS air interface. The results show that TCP works well in the LA process and can cope with the frequent switching between the coding schemes without any problem. Throughput performance is observed to be stable in all scenarios. The activation of higher coding schemes aided by TCP tuning also proves to be beneficial by the 23% increase in average throughput seen for urban areas

Self-sustainable energy efficient long range WiFi network for rural communities

WiFi is a cost effective technology of choice for network extension in the rural areas. The telecentre network can reach further to the nearby villages within 10km radius by the use of long range WiFi relay points. The challenges encountered will be the self-sustainability of the network. It should be highly energy efficient and to be powered by the very limited energy sources available in the rural environment. In this case, a modular solar based power supply system has been investigated and enhanced to achieve longer operating hours for equipment installed in the middle of the tropical rainforest and on top of a mountain. The overall design of the self-sustainable long range WiFi network model and the end-user wireless terminal shall also meet the conditions of the rural as well as the living pattern of the local people. The proposed network model has been successfully deployed in a remote village in Borneo, named Bario, connecting six nearby villages to the telecentre for Internet access

Food handlers understanding about health aspects at eatery premises in the State of Kedah: Pre and post training programme for food handlers (LPM)

This article will discuss the differences before and after food handlers attending a course to understand the safety and hygiene of their eatery premises by looking at three aspects; i.e. food hygiene, personal hygiene and eatery premises hygiene.This is a fieldwork observation research using a survey method (questionnaire) conducted on a population of food handlers who attended a course organised by SLPM.The overall population consists of approximately 8000 food operators who were undergoing trainings for food handlers throughout the state of Kedah.The number of respondent who answered the questionnaires at the pre-programme and post-programme was 400 food handlers who were at that time undergoing food handlers' trainings at schools appointed by LPM specially chosen as the sample of this study.The researchers focused only on the setting of the study which are all the way through the entire state of Kedah looking at the districts of Kulim, Kuala Muda, Kota Setar, Alor Setar and Langkawi. The analysis on the level of understanding about health among food handlers revealed that overall, food handlers responded that they really understand the importance of health in order to administer their business.The result about the overall understanding about health, indicating that before underwent the training, the level of understanding about overall health among the food providers was already high, indicating that they understand that health. Overall, the understanding of the importance of health in the running of business premises indicates a high level. In comparing the understanding level of pre-programme and post-programme, the study reveals that food handlers have already understood the importance of keeping their food, self and premises hygienic while running their business even before they underwent the course module, and their level of understanding increased after attending the course.However, the ministry should always stay alert and sensitive so as this would continue. Leaving this issue unattended will only cause a loss to the food handlers' business because the understanding of food, personal and premise hygiene is very much vital because it is the pull factor that attract customers to go to their premises of which in the end will prosper their business

Multiple Symbol Double Differential Transmission for Amplify-and-Forward Cooperative Diversity Networks in Time-Varying Channel

In the cooperative diversity wireless networks, the task to perform cooperation communication amongst neighbouring nodes is very challenging. Subjected to rapidly increasing mobility of the nodes i.e. wireless devices in fast moving vehicles and trains, at the destination end the receiver may not ideally estimate the channel characteristics and frequency offsets. Due to these circumstances which results in time-varying channels, the performance network degrades drastically. In order to enhance the performance in such environment, Double Differential (DD) modulation employing multiple symbol based detection is proposed which takes mobility environment of different nodes into consideration. By utilizing the DD transmission approach, the channel properties and frequency offset estimation is omitted in the amplify-andforward cooperative networks. The MATLAB simulation and numerical analysis on Bit Error Rate (BER) are carried out with consideration on considering flat-fading (i.e. the frequency non-selective) Rayleigh channels and when frequency offsets. The results depict that the proposed method over fading channels without channel estimation requirements and in the presence of frequency offsets performs better as compared to the conventional DD transmission. Optimized power allocation is also carried out to enhance the network performance by minimizing the BER analytical expression. It is demonstrated that the proposed power allocation scheme offers enhancement over the equally distributed power allocation approach

Community Informatics: Challenges in Bridging the Digital Divide

This paper describes how community informatics can help to overcome the digital divide between rural and urban communities in developing countries of Asia. The e-Bario project, a research initiative undertaken by a group of researchers from Universiti Malaysia Sarawak (UNIMAS) provides a context to demonstrate how information and communication technologies (ICTs) can provide opportunities for remote and rural communities to develop socially, culturally, and economically. The results of the initiative show the many ways in which ICTs can be used to improve the lives of the marginalized groups. However, other than the opportunities that the initiative provides, there are also many challenges that are encountered along the way. These challenges, based on the e-Bario experience are the major focus of this paper

Telecentre Replication Initiative In Borneo Malaysia: The Coeri Experience

There are many bridging-the-digital-divide initiatives implemented by various government agencies and non-governmental organisations throughout the world. Numerous studies have been conducted to identify the critical success factors in providing remote and rural communities equitable access to Information and Communication Technologies (ICTs). Malaysia has its fair share of successes and failures in such initiatives. One such initiative, the eBario Project, which provided ICTs to the rural and remote community in Bario, Borneo Malaysia, has been in operation over the last decade. The project was undertaken by the Centre of Excellence for Rural Informatics (CoERI), Institute of Social Informatics and Technological Innovations, Universiti Malaysia Sarawak (UNIMAS) with active participation of the local community in Bario. Critical success factors of the eBario Project include the close cooperation between the project initiator and the local community, strong support from the local champions, focus on actual needs and socio-economic goals of the community, and deployment of appropriate technologies to the remote community. Given its relative success, the eBario project has been replicated to four other rural and remote communities in Borneo Malaysia. This paper highlights the approach used in implementing telecentres within these communities and some of the lessons learnt during the replication process. The CoERI Experience provides a useful guide to policy makers, project implementers and researchers who intend to deploy telecentres in rural communities at a larger scale

Clustered Coordinator SABTS (CC-SABTS) for Beacon Transmission in IEEE802.15.4 LR-WPAN

IEEE802.15.4 standard for Wireless Sensor Network (WSN) provides low-power transmission in the low-rate wireless personal area network (WPAN). It has three types of topology: star, peer-to-peer and cluster tree. Star topology has limit to expand network. Peer-to-peer topology has a complex multihop routing during network expansion due to the large number of full-function devices. A full-function device can act as coordinator and personal area network coordinator (PAN-C). Cluster tree topology is preferable because it can expand networks using less number of full-function devices and thus reduces complexity in routing messages. A cluster tree topology consists of a wireless PAN-C, several cluster coordinators and a number of end devices. The coordinators periodically transmit beacon frames to one another to allow synchronization and communication. However, collision will happen if the coordinators transmit beacon frames at the same time and will degrade the network performance. Different mechanisms have been introduced to solve the collision problem and one of the mechanisms is superframe adjustment and beacon transmission scheme (SABTS). SABTS calculates the precise time for beacon transmission by assigning an accurate value of beacon order and superframe order for PAN-C, cluster coordinators and end devices. As the number of cluster coordinator increases, SABTS method reiterates the calculation for beacon transmission time numerously. Hence, in order to decrease the iteration, this paper introduces clustered coordinator SABTS (CC-SABTS) by clustering coordinator nodes that are separated by two length radius. The performance of CC-SABTS is simulated and evaluated using NS2 simulation software. Result shows that CC-SABTS provides better average throughput, packet delivery ratio and end-to-end delay compared to the conventional SABTS