Volume 21, Issue 1, July 2013

Eigenvalue Based Selection of Prolate Spheroidal Wave Functions for Pulse Shape Modulation [Full Text]

D. Adhikari and C. Bhattacharya

Abstract - Proper selection of ultra wideband (UWB) waveforms has become an interesting challenge such that the spectral limits of the frequency band approved by Federal Communications Commission (FCC) can be efficiently utilized. Pulse shapes based on prolate spheroidal wave function (PSWF) are a suitable choice for UWB communication systems because of their property of dual orthogonality. In this paper, we propose a set of PSWF pulses by appropriate selection of the order of pulse (n) and the time-bandwidth product (c) based on the eigenvalues of both integral and differential forms of PSWF. The selected set of pulses are analysed in terms of power spectral density (PSD), and autocorrelation function (ACF) for their applicability as basis functions in an efficient M-ary pulse shape modulation (PSM) scheme. 



Performance Evaluation of End-to-End Transmission and QoS for IP over WDM Ring Networks  

Jih-Hsin Ho

Abstract - Wavelength-division multiplexing (WDM) appears to be the solution of choice for providing a faster networking infrastructure that can meet the explosive growth of the Internet. By this reason we have been devoted to develop IP over WDM ring network and accomplished many results including proposed all-optical network architecture and we have proposed carrier sense multiple access with idle detection (CSMA/ID) protocol and have done the performance evaluation of transmission algorithms for CSMA/ID WDM ring networks. We studied in depth the existing problem in CSMA/ID WDM ring networks included to achieve end-to-end transparent transmission and quality of service (QoS). We propose the address resolution mechanism between WDM ring network and heterogeneous networks. We also propose end-to-end differentiated QoS and an analytical model developed to evaluate the performance. 


Enhancing Capacity of Code Division Multiple Access Network 

M. Nasim Faruque, Dr. S. N. Ahmad and Dr. S. Qamar

Abstract - The major concern of users and the network operators are the continuous increase in the cellular mobile users and the associated impairments in the system. Global system for mobile communication (GSM) system is bandwidth limited but the universal mobile telecommunication services (UMTS) using CDMA system is interference limited. Both the band limited and interference limited systems has attracted an increase in the number of users that are not given access into the network due to insufficient channels and poor quality of radio channels. This paper looks at the CDMA system and finds the suitable approach toenhance the cellular capacity using cell sectoring. The enhanced cell capacity can provide more mobile users access to network by making the optimal use of the available static resource spectrum i.e. channel. The cell sectoring technique utilizes the directional antenna system to reduce the number of interfering users so that co-channel interference which is prevalent in CDMA system is drastically reduced for optimum channel usage. A drive test measurement is carried out on an existing mobile cellular network system with CDMA access technology at Noida, NCR Delhi. The derived models for the enhancements of cellular capacity through cell sectoring are simulated using Matlab. The results show that the reduction in interference brings about an increase in the number of users that access the network. 

Audio Watermarking in Image by Using Radon – Wavelet Transforms [Full Text]

Osama Qasim Jumah Al-Thahab and Heba Abdul-Jaleel Alasady

Abstract - The rapid growth of digital media and communication network has highlighted the need for Intellectual Property Rights (IRP) protection technology for digital multimedia. Watermarking of multimedia data has become a hotspot for research in recent years. Watermarking can be used to identify the owners, license information, or other information related to the digital object carrying the watermark. Watermarks can provide the mechanism for determining if a particular work has been tampered with or copied illegally. In this paper, a novel algorithm for robust audio watermarking is presented in image using wavelet transform based on image, and radon transform on audio file for the first time. The motivation of choosing image as a cover is driven by the fact that human visual system is less sensitive than human auditory system thus an image provides better masking effect. The algorithm is based on decomposition of images using Haar wavelet basis. Performance of the algorithm has been evaluated extensively, and simulation results are presented to demonstrate the imperceptibility and robustness of the proposed algorithm.