Volume 2, Issue 5, August 2011

Evaluation of Kalman Filtering Based Channel Estimation for LTE-Advanced
Pages: 1-6 (6) | [Full Text] PDF (345 K)
Saqib Saleem and Qamar-ul-Islam
Department of Communication System Engineering at Institute of Space Technology, Islamabad, Pakistan

Abstract — For high data rate multimedia services and growing demand of wireless internet, in 2007 ITU invited proposals for 4th Next Generation Communication systems, for which 3GPP proposed LTE-A, based on Rel-10, fulfilling the requirements of IMT-A. In this paper extension of two linear frequency-domain channel estimation techniques, LSE and LMMSE are analyzed by using Kalman Filtering Algorithm. The performance of LMMSE-Kalman is better than LSE-Kalman as first one uses the second order noise and channel statistics. Two channel parameters are used for analysis, channel filter length, in terms of Channel Impulse Response (CIR) samples and multi-path channel taps. MATLAB Monte Carlo Simulations are performed to make performance and complexity comparison of these two methods. The performance is evaluated in terms of Mean Square Error (MSE) and complexity shows the computational time taken by the channel estimator for different MIMO systems.
 Index Terms — LSE, LMMSE, DFT, DCT, Windowed-DFT, LTE and MIMO-OFDM
Managing the QoS and Security of VPNs using VDSL
Pages: 7-12 (6) | [Full Text] PDF (249 K)
Khalid Bashir and M. A. Naeem
School of Agriculture and Resource Economics, University of Western Australia
Department of Computer Science, The University of Auckland, New Zealand

Abstract — The goal of this research work is to find how to improve quality of service (QOS) and security of virtual private network (VPN) on the present copper telephone wire network by using the very high speed digital subscriber line (VDSL) technology in the best possible way. Copper pairs connected to practically every household from one of the most common access networks in the field of telecommunications. The evolution of this copper based network into a broadband fiber network is a long process. Hybrid fiber-copper based solutions seem to offer a good way to upgrade the copper networks gradually towards all fiber networks. Digital subscriber line (DSL) technologies offer a possibility to reuse part of the huge existing copper base for broadband connectivity. VDSL offers the most transmission capacity, planned to operate over very short copper loops of a few hundred meters.
 Index Terms — Quality of Service, VDSL, Security, VPN and Issues
Mitigating App-DDoS Attacks on Web Servers
Pages: 13-18 (6) | [Full Text] PDF (512 K)
Ms. Manisha M. Patil and Prof. U. L. Kulkarni
Dr. D.Y. Patil College of Engineering and Technology, Kolhapur, (Maharashtra), India
Konkan Gyanpeeth’s College of Engineering, Karjat, Dist. Raigad, (Maharashtra), India

Abstract — In this paper, a lightweight mechanism is proposed to mitigate session flooding and request flooding app-DDoS attacks on web servers. App-DDoS attack is Application layer Distributed Denial of Service attack. This attack prevents legitimate users from accessing services. Numbers of mechanisms are available and can be installed on routers and firewalls to mitigate network layer DDoS attacks like SYN-flood attack, ping of death attack. But Network layer solution is not applicable because App-DDoS attacks are indistinguishable based on packets and protocols. A lightweight mechanism is proposed which uses trust to differentiate legitimate users and attackers. Trust to client is evaluated based on his visiting history and requests are scheduled in decreasing order of trust. In this mechanism trust information is stored at client side in the form of cookies. This mitigation mechanism can be implemented as a java package which can run separately and forward valid requests to server. This mechanism also mitigates request flooding attacks by using Client Puzzle Protocol. When server is under request flooding attack source throttling is done by imposing cost on client. Cost is collected in terms of CPU cycles.
 Index Terms — DDoS attacks, App-DDoS and Trust
Analysis of Multiple Users Watermarking in Spatial Domain
Pages: 19-22 (4) | [Full Text] PDF (1640 K)
Rohit M Thanki, Rahul K Kher, Divyang D Vyas
EC Department of Institute of Computer and Communication Technology for Women, New Vallabh Vidyanagar, Gujarat, India
EC Department of G H Patel College of Engineering & Technology, Vallabh Vidyanagar, Gujarat, India
EC Department at Darshan Institute of Technology & Engineering, Rajkot, Gujarat, India

Abstract — An image authentication technique by embedding digital “watermarks” into cover image is proposed. Digital watermarking is the process of inserting a digital signal of a defined pattern into digital data. This is used identify the owner of the work, to authenticate the content, to trace illegal copies of the work and other similar purposes. This paper provides a study of multiple users watermarking schemes in spatial domain where different user are embed different watermark or message into one cover image which provides using one watermarked image, we transmit more information in secure manner to reception side. The implement provides good knowledge about basic digital right management system. The analyses of different stage watermarked image have been done by parameters like PSNR (Peak Signal to Noise Ratio), NAE (Normalized Absolute Error) and MSE (Mean Square Error).
 Index Terms — Digital Watermark, Multiple User, Noisy Image and Spread Spectrum Watermarking
High Speed Performance of Electrooptic Polymer Modulator Devices in Advanced Optical Communication Systems
Pages: 23-29 (7) | [Full Text] PDF (310 K)
Mohamed A. Metawe'e
Higher Institute of Engineering and Technology in El-Arish, Egypt

Abstract — Electrooptic polymer modulator devices have been extensively studied and explored during the last few years. They have intrinsic advantages over conventional materials such as high-speed operation, compatibility with other materials and substrates, and the ability to make complex configurations and arrays. On the other hand, there have been problems with thermal stability, power handling, and drift. These problems are currently the subject of intense research and must be solved before commercial devices become available. This paper has been deeply investigated the high speed performance of polymer electrooptic modulator devices in advanced optical communication systems over wide range of the affecting parameters. We have taken in to account the study of modulator signal quality, sensitivity bandwidth product, switching voltage, transmitted signal bandwidth, device sensitivity, transmission bit rates under the effect of operating optical signal wavelength, modulator dimensions (i. e, modulator length, width and thickness), ambient temperature, and effective relative refractive index difference as a measurement of high speed performance operation.
 Index Terms — Optical Polymers, Integrated Optics Devices, High Speed Performance, Communication Systems and Modulator Sensitivity
The Role of Computer Program in New Innovation
Pages: 30-33 (4) | [Full Text] PDF (2650 K)
Khaled A. Hamid Elnems
Egyptian Inventor & Cad Tec., U.A.E

Abstract — The Computer Program can playing a big roles in our lives, we only used the computer for Non-core like (Chat, game, music, etc). But it can be used for a lot of benefits work to controlling, Admin our Life and save money, by provision of the electronic chips by using the Computer Program.
 Index Terms — Computer Programming, New Innovation and Control
Discovering Services during Design Phase Using UML
Pages: 34-39 (6) | [Full Text] PDF (474 K)
Arram Sriram and Shaik Shah Nawaz
Department of CSE, Aurora Engineering College, Bhongir, AP, India
Department of CSE, Aurora Engineering College, AP, India

Abstract — Service discovery has been recognized as an important aspect in the development of service centric systems, i.e., software systems which deploy web services. To develop such systems, it is necessary to identify services that can be combined in order to fulfill the functionality and achieve quality criteria of the system being developed. In this paper, we present a framework supporting design impelled and ranked services detection (DIRSD) - that is the exploit of services in QOS bead ranking order, which can provide functionalities and satisfy properties and constraints of systems as specified during the software design phase. Detailed system design is a compulsion and an assumption about iterative design process that allows the formulation of design models of service-centric systems based on the exploited services. The framework is composed of a query extractor, which derives queries from behavioral and structural UML design models of service centric systems, and a query execution engine that executes these queries against service registries. The paper describes a prototype tool that we have developed to demonstrate and evaluate our framework and the results of a set of preliminary experiments that we have conducted to evaluate it.
 Index Terms — Design, UML, Services and Framework
Buffer Efficient Fast Broadcasting Scheme
Pages: 47-51 (5) | [Full Text] PDF (289 K)
Mohammad Saidur Rahman, Mohammad Saiedur Rahaman, Ahmed Ridwanul Islam and Abhijit Bhowmik
American International University-Bangladesh, Banani, Dhaka, Bangladesh

Abstract — A popular video can be broadcasted by partitioning the video into segments, which are broadcast on several channels simultaneously and periodically. This approach permits multiple users to share channels that lead to higher bandwidth employment. Previous schemes generally focus on reducing clients’ waiting time. This work studies another important issue, namely client buffer1 savings. A reverse fast broadcasting (RFB) scheme is introduced to improve the buffer problem. RFB has the identical waiting time like FB. We introduced a new Buffer Efficient Fast Broadcasting scheme that has smaller buffer requirement and less waiting time than RFB and FB.
 Index Terms — VOD, Buffer Efficient, Fast Broadcasting and Near VoD Scheme

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