International Journal of Computer Networks and Communications Security

Volume 1, Issue 1, October 2014

 

 

 

Evaluation of Channel Estimation Combined with ICI Self-Cancellation Scheme in Doubly Selective Fading Channel

Pages: 1-7 (7) | [Full Text] PDF (505 KB)
Lien Pham Hong, Quang Nguyen Duc, Dung Mac Duc
University of Technical Education Ho Chi Minh City, Vietnam
Ho Chi Minh City University of Technology, Vietnam

Abstract -
Orthogonal Frequency Division Multiplexing (OFDM) is a modulation scheme, which is used in several wireless systems for transferring data at high rate. The multi path fading channel and the frequency offset between the transmitted and received carrier frequencies introduce ICI (Inter Carrier Interference). ICI effects the OFDM symbols and degrades the system performance. This paper proposes a solution: combine channel estimation and ICI self-cancellation to combat against ICI in doubly selective fading channel. The simulation results show the effect of this solution.
 
Index Terms - OFDM, ICI, Wireless Systems, Inter Carrier Interface
 

Impact of Randomness on MAC Layer Schedulers over High Speed Wireless Campus Network in IEEE802.11e

Pages: 8-13 (6) | [Full Text] PDF (350 KB)
M. K. Alam, S. A. Latif, M. Akter and M. Y. Arafat
Department of Electrical and Computer Engineering, International Islamic University Malaysia, Kuala Lumpur, Malaysia

Abstract -
IEEE802.11e standard provides an EDCA mechanism to ensure the QoS using service differentiation function for IMM traffics through the WCN. In an EDCA mechanism, IMM traffics have been classified into four categories and each category has specific priority. Many EDCA schedulers allow these traffics to access the channel based on assigned priorities. The IMM high priority traffic is high delay sensitive and required high bandwidth to ensure QoS over the networks. Scheduling mechanism is the effective way to satisfy IMM traffic but it cannot give guarantee because of the randomness of some EDCA schedulers or proposed networks. In order to provide the QoS, scheduling mechanism is the challenging issue to transmit IMM traffic through the channel and it is still need to be solved over WCN. This work aims to examine the effect of the randomness on different MAC layer schedulers performance and evaluates the performance of the proposed schedulers using different performance metrics in WCN.
 
Index Terms - Scheduling Algorithms, Seed Values, WCN, Multimedia Applications, Back-off Algorithm
 

Performance Evaluation of PAPR Reduction with SER and BER by Modified Clipping & Filtering in 3GPP LTE Downlink

Pages: 14-22 (9) | [Full Text] PDF (1.9 MB)
M. Y. Arafat, S. Abd. Latif, M. K. Alam, S. S. Haque, M. Akter
Department of ETE, RUET, Rajshahi-6204, Bangladesh
Department of Electrical and Computer Engineering, International Islamic University Malaysia, Kuala Lumpur, Malaysia

Abstract -
This paper work focuses on performance analysis of PAPR reduction of orthogonal frequency division multiplexing (OFDM) using amplitude clipping & filtering based design. Now a days one of the most proficient multi-carrier transmission techniques widely used today is orthogonal frequency division multiplexing (OFDM) which has been implemented by the next generation wireless communication technology: Long Term Evolution (LTE). Extra robustness to multipath fading and impulse noise is provided OFDM. It eliminates inter symbol interference (ISI) & inter carrier interference (ICI) with certain procedure. Therefore peak to average power ratio (PAPR) is the basic problem with OFDM. However in this paper we proposed a reduction procedure of the PAPR by using clipping and filtering. Here we use a composed high pass , low pass & Chevyshev band pass filter II after amplitude clipping to reduce the PAPR. The performance of the system in terms of bit error rate (BER) and symbol error rate (SER) is also investigated as a new filter based clipping method is proposed. Our proposed clipping method with and composed high pass the Chevyshev bandpass filter II in PAPR performance of the system with a little compromise of BER & SER showing the significant improvement in Quadrature Amplitude Modulation (QAM).
 
Index Terms - FDM, LTE, Chevyshev, BER, Clipping and Filtering (CF)
 

The Multi-Objective Genetic Algorithm Based Techniques for Intrusion Detection

Pages: 23-29 (7) | [Full Text] PDF (212 KB)
Gulshan Kumar
Department of Computer Application, SBS State Technical Campus, Ferozepur, Punjab 152004, India

Abstract -
The Multi Objective Genetic Algorithms (MO- GAs) are one of the most widely used techniques that have the capability to find the solution to the problem having multiple conflicting objectives like Intrusion Detection. It is a population based technique capable of producing a set of non-inferior solutions that exhibit the classification trade-offs for the user. This capability of MOGA can be exploited for generating optimal base classifiers and ensembles thereof for Intrusion Detection. This paper explores the various MOGAs proposed in the literature along with their pros and cons. The motivation for the use of MOGA and its issues are high- lighted. Finally, the chapter highlights the concluding remarks.
 
Index Terms - Genetic algorithm, Intrusions, Intrusion, Detection, Network Security, Security Threats