Volume 5, Issue 2, February 2014

A Comprehensive Study of Open-loop Spatial Multiplexing and Transmit Diversity for Downlink LTE

Mahmoud AMMAR, Bechir NSIRI, Walid HAKIMI and Messaoud ELJAMAI

University of Tunis El Manar, National Engineering School of Tunis(ENIT), LR99ES2, Sys’com Lab, BP.37 Le Belvédère 1002 Tunis, Tunisia

Abstract - Long Term Evolution (LTE) , which standardized by the 3GPP group, is designed to have wider channels up to 20MHz, with low latency and packet optimized radio access technology. The peak data rate envisaged for LTE is 100 Mbps in downlink and 50 Mbps in the uplink. The 3GPP has chosen the Orthogonal Frequency Division Multiple Access as the radio access technology due to his simple implementation in receiver and high performance and high spectral efficiency. In addition OFDMA technology, Different MIMO transmission methods are deployed to achieve data rate compliance with the LTE standards. To achieve high throughput required by the downlink LTE system, Adaptive Modulation and Coding (AMC) has to ensure a BLER value smaller than 10%. The SNR-to-CQI mapping is required to achieve this goal. In this paper, we made a comprehensive study to evaluate the performances of open loop spatial multiplexing (OLSM) and transmit diversity (TxD) in downlink LTE system for different transmission mode. A comparison is performed between these transmission modes to achieve optimal utilization of the resources. We observe that, at lower values of SNR, TxD give higher throughput and reduced Block Error Rate (BLER) but, when the SNR value are increased, OLSM performs better than the TxD in terms of throughput.

Index Terms - Layer Mapping, MIMO, OLSM, Precoding and Spatial Multiplexing

Security Issues and Contradict Measures in Wireless Mesh Networks

Pages: 7-13 (7) | [Full Text] PDF (183K)

Shabana Mustafa, Ali Raza and Raeesa Qadeer

Department of Computer Science and Engineering, University of Engineering & Technology, Lahore, Pakistan

Abstract - As wireless networks have evolved into next generations, Wireless Mesh Networks (WMNs) have proved to be a massive infrastructure for better communication between enormous entity nodes. WMNs are extremely dependable, as every node is associated with all others likewise sketched in mesh layout. WMN network nodes consist of clients and routers, whereverthese play responsibilities as both routers and hosts.These mesh nodes transmit packets ahead as for theothers, this direct transmission is carried out up to the range of their destinations. Due to wireless associations in WMNs, there occur more chances of active and passive attacks to hit the mesh infrastructure. Apart from such hits, the distortion in messages is also prone to WMNs. There is a probability that a nodecan conciliate, when the system becomes prone to malicious attacks cause severe harm to networks. WMNs might tend to bevibrantfor the reason that regular changes can be made in both the mesh layout and the noderelationships. Major security challenges to WMNs are typically the same as challenges faced by all other networks; containing availability, confidentiality, authenticity and integrity. This paper includes the WMN security challenges, issues and the looms on hand to secure data communication between mesh nodes.

Index Terms - Wireless Mesh Networks, Mesh Router, Fairness of Network, Denial of Service, Compromising Nodes and Routing Protocol

Optimized Resource Selection to Promote Grid Scheduling Using Hill Climbing Algorithm

Pages: 14-19 (6) | [Full Text] PDF (407K)

N. Krishnamoorthy and R. Asokan

Department of Computer Science and Engineering, Kongu Engineering College, Erode, India
Kongu Nadu College of Engineering and Technology, Thottiyam, Trichy, India

Abstract - Grid computing is gaining ground in academia and commerce moving from scientific-based applications to service oriented problem solving environments. Grid is a distributed large-scale computing infrastructure providing dependable, secure, transparent, pervasive, inexpensive, and coordinated resource sharing. Resource selection and use are necessary to enhance application performance. Grid task scheduling is a most important grid system technology being a NP complete problem to schedule tasks on appropriate grid nodes. This study uses hill-climbing heuristics for optimizing the scheduling. Simulations validate the proposed algorithm’s performance, and results are evaluated by Makespan. Makespan values of best solutions are recorded throughout optimization iterations and minimum time cost time for all tasks completed.

Index Terms - Grid Computing, Grid Scheduling, Performance and Hill Climbing-Makespan

An Overview of Intrusion Detection System (IDS) along with its Commonly Used Techniques and Classifications

Pages: 20-24 (5) | [Full Text] PDF (514K)

Hussain Ahmad Madni Uppal, Memoona Javed and M.J. Arshad

Department of Computer Science and Engineering, UET, Lahore, Pakistan

Abstract - The area of intrusion detection is the central concept in overall network and computer security architecture. It is an important technology in business sector as well as in research area. By monitoring the computer and network resources, Intrusion Detection System (IDS) detects any of the misuse or unauthorized access which is basically an attack to these resources. Then it alerts and informs administrator for occurrence of an intrusion. Several methods can be used to detect an intrusion. In this paper, we have discussed the introduction of Intrusion Detection System, its types and then different techniques that are commonly used. This paper will be helpful for the new researchers who want to know the basic knowledge of intrusion detection systems. It will help them to understand what intrusion detection is and what are the techniques commonly used for it.

Index Terms - Intrusion Detection System, Security, Resources and Techniques

Survey of Keylogger Technologies

Pages: 25-31 (7) | [Full Text] PDF (373K)

Yahye Abukar Ahmed, Mohd Aizaini Maarof, Fuad Mire Hassan and Mohamed Muse Abshir

Department of Computer Science, Faculty of Computer Science & Information Systems, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia

Abstract - Keyloggers are type of a rootkit malware that capture typed keystroke events of the keyboard and save into log file, therefore, it is able to intercept sensitive information such as usernames, PINs, and passwords, thus transmits into malicious attacker without attracting the attention of users. Keyloggers presents a major threat to business transactions and personal activities such E-commerce, online banking, email chatting, and system database. Antivirus software I commonly used to detect and remove known keyloggers. However, it cannot detect unknown keyloggers. This paper presents an overview of keylogger programs, types, characteristics of keyloggers and methodology they use. A case study on Blackbery is used as a real time example in this paper. Finally we will analyze the current detection techniques, and explore several proactive techniques.

Index Terms - Keylogger, Hooking, Signature-Based, Malware Rootkits, Anomaly Based, OS and API

Volume 5, Issue 2, February 2014

IJCST Managemet

Current Issue

Recent Issues

Author Guidelines

IJCST RSS Feeds

News & Updates