International Journal of Communications

E-ISSN: 1998-4480
Volume 9, 2015

Notice: As of 2014 and for the forthcoming years, the publication frequency/periodicity of NAUN Journals is adapted to the 'continuously updated' model. What this means is that instead of being separated into issues, new papers will be added on a continuous basis, allowing a more regular flow and shorter publication times. The papers will appear in reverse order, therefore the most recent one will be on top.

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Volume 9, 2015

Title of the Paper: An Efficient Approach for MFCC Feature Extraction for Text Independant Speaker Identification System


Authors: R. Ajgou, S. Sbaa, S. Ghendir, A. Chemsa, A. Taleb-Ahmed

Pages: 114-122

Abstract: This paper presents an efficient noise-robust feature extraction method for remote speaker identification system. Mel frequency cepstral coefficients (MFCCs) are the most widely used front ends in the state of the art speaker identification systems. One of the major problem with MFCCs is that it deteriorates in the presence of noise. To overcome this problem, we have propsed an efficient feature extraction technique based on the combination between the MFCC and parameters of too pole filter parameter (Autoregressive model parameters) that characterize the human vocal tract. The system employs a robust speech feature based on MFCCAR modeled by GMM. An effective speech enhancement methods is essential for speaker recognition, an overview of some recent speech enhancement techniques of the state of the art have been presented where we have investigated its effects on our speaker identification system accuracy based on MFCCAR. TIMIT database with speech signals from 200 speakers has been used in Matlab simulation. The first four utterances for each speaker could be defined as the training set while 1 utterance as the test set. Experimental results show that proposed methods achieve better performance. The use of MFCCAR approach has provided significant improvements in identification rate accuracy when compared with MFCC, deltaMFCC and PLP in noisy environment. However, with regard to runtime, MFCCAR requires more time to execute. In terms of effects of reverberant speech enhancement methods, it is shown a significant improvement for Tracking of noise algorithm method.

Title of the Paper: Analyze of SIP Messages and Proposal of SIP Routing


Authors: F. Csoka, I. Baronak, E. Chromy, L. Kockovic

Pages: 109-113

Abstract: This paper deals with the functionality of SIP and design of an efficient and optimized process for routing SIP messages. It is used for creation of VoIP calls. This routing logic, in a form of a script, should be faster and simpler than current implementations. It should not include any functionality that is not necessary for initiating VoIP calls on LAN.

Title of the Paper: Comparison of Ray Theoretical Propagation Models with High Performance Computing


Authors: M. B. Tabakcioglu

Pages: 105-108

Abstract: How electromagnetic wave propagates in the environment including obstructions that can be buildings, trees or hills? Electromagnetic waves are reflected or diffracted from these obstructions. To predict the coverage, field strength, relative path loss of electromagnetic waves at the receiving position, superabundant electromagnetic wave propagation models, which are classified to some classes such as ray tracing based models and numerical integration based models, are proposed. In this study some ray theoretical based propagation models are explained shortly. Uniform theory of diffraction (UTD), slope diffraction (S-UTD) and Slope diffraction with convex hull (SUTD-CH) models are compared in accordance with accuracy of predicting field and computation time. Furthermore comparison results of high performance parallel computing are given.

Title of the Paper: Frequency-Selective IQ Imbalance in Zero-Second-IF Transceivers for Wide-Band mmW Links


Authors: Ainhoa Rezola, Juan Francisco Sevillano, David Del Río, Iñaki Guruceaga, Roc Berenguer, Igone Vélez

Pages: 98-104

Abstract: This article deals with the analysis and mitigation of one of the most prominent impairments found in wideband zerosecond-IF transceivers, namely frequency-selective IQ imbalance. IQ imbalance can significantly reduce the performance of a communication system if it is not appropriately compensated. This article presents a mathematical analysis, followed by a compensation technique. Compensation processing, known as predistortion, takes place at the digital baseband and it is based on test tones and spectral measurements. The compensation strategy facilitates automatic IQ imbalance compensation procedure and it requires a minimum of extra hardware. The performance of the algorithm is evaluated in a transceiver with 64-QAM modulation and 1GHz of bandwidth implemented with real hardware. The results presented in the article suggest that the use of this technique is able to mitigate the impact of the IQ imbalance effects in wideband systems.

Title of the Paper: Application of Multivariate Empirical Mode Decomposition in EEG signals for Subject Independent Affective States Classification


Authors: Haiyan Xu, Konstantinos N. Plataniotis

Pages: 91-97

Abstract: Physiological signals, EEG in particular, are inherently noisy and non-linear in nature which are challenging to work with using conventional linear signal processing methods. In this paper, we are adopting a new signal processing method, Multivariate Empirical Mode Decomposition, as a preprocessing method to reconstruct EEG signals according to its instantaneous frequencies. To test its effectiveness, we applied this signal reconstruction technique on EEG signals for a 2-dimensional affect states classification application. To evaluated the proposed EEG signal processing system, a three-class classification experiment were carried out on the Emobrain dataset from eNTERFACE’06 with K-nearest neighbours (KNN) and Linear Discriminate Analysis (LDA) as classifiers. A leave-one-subject out cross validation process were used and an averaged correct classification rate of 90.77% were achieved. Another main contribution of this paper was inspired by the growth of non-medical grade EEG headsets and its potential in advanced human-computer interface design. However, to reduce cost and invasiveness, consumer grade EEG headsets have far less number of electrodes. In this paper, we used emotion recognition as a case study, and applied Genetic Algorithm to systematically select the critical channels (or sensor locations) for this application. The results of this study provide much needed insights on sensor configuration for future consumer-grade EEG headset design.

Title of the Paper: Observer-Based Synchronization for Coupled Non Identical Chaotic Systems


Authors: Rym Ben Mahmoud, Mohamed Benrejeb, Pierre Borne

Pages: 86-90

Abstract: In this work, the proposed framework for the synchronization of two non identical continuous-time chaotic systems, based on the use of observer concept and aggregation technique, is applied, with success. Sufficient conditions for synchronization are obtained by the use of Borne and Gentina practical criterion for stabilization study associated to the Benrejeb arrow form matrix for system description. Application of the proposed approach to two master-slave Lorenz and Rossler systems shows the efficiency of the proposed approach.

Title of the Paper: GPU Computation Acceleration of GRASS GIS Modules for Predicting Radio-Propagation


Authors: Igor Ozimek, Andrej Hrovat, Andrej Vilhar, Tomaž Javornik

Pages: 76-85

Abstract: GPGPU (General-Purpose Computing on Graphics Processing Units) is a parallel computation technique that has become very popular with the advent of high performance and relatively low priced programmable GPU (Graphics Processing Unit) adapters and of the software tools required for general computing (compilers for computing languages such as OpenCL, etc.). GPU computing can offer massive computation acceleration for algorithms that fulfill certain requirements and map well to the GPU architecture. GPUs were originally developed for displaying and processing raster images, and so can be applied efficiently for fast processing of the rasterized geographic and other maps used in geographic information systems such as GRASS GIS (Geographic Resources Analysis Support System / Geographic Information System). GRASS-RaPlaT (Radio Planning Tool for GRASS) is a GRASS add-on for simulating radio signal propagation in actual geographic environments. In the case of large areas and relatively high resolution, simulations can become computationally demanding, taking a considerable amount of time to accomplish. GPU parallelization of radio propagation modules is therefore presented and the results analyzed, together with the conditions that must be fulfilled to employ GPU computation successfully and achieve considerable computation speedup.

Title of the Paper: Performance Analysis of CDMA in Optical Transmission Using PPM Signaling


Authors: N. Alsowaidi, Tawfig Eltaif, M. R. Mokhtar, K. Alaghbari

Pages: 71-75

Abstract: In this article we aim to theoretically investigate the performance of optical code-division multiple-access (OCDMA) system with M-ary pulse-position modulation (PPM) signaling. The system is implemented on both direct sequence (DS) and spectral amplitude coding (SAC) using different spreading sequence codes, and considering the effects of the loss produced from the splitting during encoding and decoding, the channel loss, and multiple access interference (MAI). It is noticed that, PPM levels increases system improves significantly. In addition, SAC-Optical PPM-CDMA system has better performance than DS-Optical PPM-CDMA system.

Title of the Paper: Maritime Visible Light Communication with Sea Spectrum Models


Authors: Hyeongji Kim, Atul Sewaiwar, Yeon-Ho Chung

Pages: 67-70

Abstract: This paper presents a Visible Light Communications (VLC) system concept in maritime environments to overcome the limitations of conventional maritime wireless communication. The proposed concept is a cost effective method of implementation using LED-based lighthouse and beacons. The transmission system presented for shore-to-sea communication considers unique properties of maritime environments where wave height, wind speed, etc. exist. Computer simulations are conducted based on the PM and JS spectrum models with various sea states for analysis. It is found that the JS model outperforms the PM model. The transmission distance of the proposed system is dependent upon the LED power and sea states. It is found to be approximately 1,000m for the sea state 6 of the JS model at a BER of 10^(-3).

Title of the Paper: Mobile Agent Based QoS Provision with Bee Communication in Vehicular Network


Authors: Abubakar A. Mua’zu, Low T. Jung, Ibrahim A. Lawal, Peer A. Shah

Pages: 58-66

Abstract:  The vehicular ad hoc network (VANET) is one of the most favorite models for intelligent Transport System (ITS) to provide safety and comfort on road. The high speed mobility and the intermittent connection features of the VANET make Quality of Service (QoS) provisioning a challenging task for the delay sensitive applications. In this research, we use intelligent mobile agents to improve the efficiency of VANET traffic and ensure sustainability of the network. The propose scheme is inspired by the concept of biological paradigm of communication between bees when searching for food. The mobile agent architecture is used to exchange status information among the nodes for high quality data transmission. These are achieved by calculating the corresponding QoS provision values based on QoS metrics before selecting the optimal, reliable and stable route between the source and the destination. Simulation results show the proposed scheme can robustly improve the routing performance in term of network throughput, packet loss rate and effectively reduces the network delay.

Title of the Paper: Evaluation of Performance and Complexity Comparison for Coding Standards HEVC vs. H.264/AVC


Authors: Zoran M. Milicevic, Zoran S. Bojkovic

Pages: 53-57

Abstract: In order to compare the performance and complexity without significant rate-distortion performance degradation, the HEVC coder vs. H.264/AVC coder are tested for the fixed Quantization Parameter (QP) value, when Main profile, appropriate motion vector (MV) search ranges and hierarchical B pictures are used. Simulation results have shown that the encoding time saving is reduced up to 50%, while the bit-rate is reaching over 69% depending on the tested video sequences, when reference HEVC software HM-15.0 is compared to reference H.264/AVC software JM 18.6. However, there was negligible loss in term Signal-to-Noise Ratio (SNR).

Title of the Paper: Advanced Communication Diagnostics in ISES Remote Experiment


Authors: M. Gerža, F. Schauer, K. Vlček

Pages: 43-52

Abstract: This paper focuses on the analysis and diagnosis of communication between clients and the physical hardware of remote laboratories based on ISES (Internet School Experimental System). Many different types of connections are allocated to use comfortably the real-time experimenting in a remote laboratory. Each ISES unit includes some communication mechanism to provide data to underling or superior unit to process it in a given way. The main reason for proper communication is to deliver control commands from clients to the physical hardware to perform preset tasks in order to observe, measure and obtain real physical or electrical phenomena in form of data. The ISES remote experiment provides clients a unique educational tool for the purpose of the desired phenomena understanding. This tool is particularly useful for distant students, who are often hampered to attend experimental courses. In the first chapter, the state of the art of the ISES remote experiment concept is introduced. In the next chapter, the basic analysis of the data communication, necessary for a cooperation of the units involved, i.e. physical hardware, Measureserver®, Internet and client, is presented. Further chapter proposes improvements of the most decisive communication segments. Three advanced diagnostic systems are introduced and used to prevent or significantly reduce occasional faults and anomalies. The first is the internal unit diagnosis, solving various communication faults inside the ISES remote experiment. The second one acts as the network traffic diagnosis, dealing with the detection, identification and quantification of anomalies, which can create congestion in network and may have an ill effect on the administrators or clients. As the third one, the cognitive fault diagnosis system is described with the aim of monitoring the distributed sensor network. It makes advantage of spatial and temporal relationship among sensor units connected to the ISES physical hardware to give sufficient information for failures reduction or avoidance. The last chapter summarizes all benefits of these diagnostic systems for ISES remote experiments reliability.

Title of the Paper: Uncertainty Test and Improvement in Quantum Information Transfer Employing Shannon Reverse Theorem


Authors: Mustapha Y. Abubakar, Low T. Jung, Nordin M. Zakaria

Pages: 36-42

Abstract: Just as data becomes important with regard to safety and security as well as effectiveness associated with information transfer, from a source to a destination node, the particular issue for how this data could possibly be compacted in a message for transfer can be another vital issue. In this paper we show up an experiment where arbitrary parameters could be chosen within a probabilistic manner of certainty and uncertainty. We explain results of the test base on the theory of Shannon entropy of classical information. This means a measured condition will have significantly less details in it because of the guarantee of pure states, the entropy of a pure state is zero. The higher the entropy the higher qubits can be enclosed in a message. We evaluate the way our test provide chances of retrieving more information out of a variable that has less probability to be selected, consequently recording a high number of entropy than the variable with a higher probability. We also show how the Shannon reverse theorem of both the classical and quantum channel could be simulated from noisy channel to noiseless one and vice versa.

Title of the Paper: Design and Analysis of an Optimal Orbit Control for a Communication Satellite


Authors: Santosh Kumar Choudhary

Pages: 28-35

Abstract: In this article, design and analysis of an optimal orbit control for a communication satellite is investigated. It is the challenging task and critical importance to control the orbit of a communication satellite especially the one used for worldwide communication. The main objective of this work is to evolve a design based on modelling and simulation of an optimal orbit controller for a satellite orbiting into a a geostationary orbit. This article first presents the mathematical model of satellite orbital dynamics and then illustrates the basic idea and technical formulation for controller design. The paper briefly explains the linear quadratic regulator (LQR) design method for optimal feedback control of the satellite orbital system. This approach has been considered in order to assure high control performance of the system. The simulation results show that if the satellite orbital system follow the control pattern obtained through the MATLAB simulation, the use of fuel for the thrusters can be optimized and the satellite orbit perturbation can be controlled within the specified design requirements. This can increase the efficiency of the thrusters and the lifetime of the satellite.

Title of the Paper: Level Crossing Rate of SC Receiver Output Signal in the Presence of Gamma Shadowing and k-µ or Rician Multipath Fading


Authors: Dragana S. Krstic, Suad Suljovic, Mihajlo C. Stefanovic, Muneer Masadeh Bani Yassein, Danijela Aleksic

Pages: 19-27

Abstract: In this paper, the wireless communication system with dual SC receiver operating over shadowed multipath fading channel is considered. The multipath fading is k-µ or Rician. The received signal experiences the short term fading which is resulting in SC receiver envelope variation and Gamma long term fading resulting in SC receiver envelope power variation. The closed form expressions for joint probability density functions of SC receiver output signal envelope and their first derivative of SC receiver output signal envelope are calculated for both, k-µ and Rician fading. These expressions are used for evaluation of average level crossing rate of SC receiver output signal envelopes. The numerical expressions are plotted to show the effect of Rician fading severity parameter and Gamma shadowing severity parameter on the average level crossing rate of SC receiver output signal envelope.

Title of the Paper: A New Design and Analysis of Microstrip-Fed Ultra-Wideband Printed Monopole Antenna


Authors: M. A. Matin

Pages: 15-18

Abstract:  A new microstrip-fed monopole antenna with simple planar structure of size 24×28×1.6 mm3 is presented for ultra-wideband (UWB) applications. The antenna structure consists of V-shaped patch, microstrip-fed line and partial ground plane structure. With the inclusion of U-shaped slot on to the patch, a frequency notched characteristics is achieved which can reject the frequency band of 5.15- 5.825 GHz. The effects of dimensional parameters on antenna performance such as length and width of U shaped slot, size of the ground plane have been investigated through a parametric study and design results from parametric simulations are presented. The electric current distributions on the patch are also exhibited in this paper. Simulation results confirm that the presented antenna has a large bandwidth below (S11≤ -10 dB) covering the ultrawideband frequency range of (3.15-13.2 GHz) with band notch characteristics at WLAN band. The proposed antenna creates a monopole like pattern in the E-plane and omnidirectional radiation pattern in the H-plane.

Title of the Paper: Safety of Data Warehouse for Remote Laboratories in Laboratory Management System and Network of Road Junctions


Authors: L. Pálka, L. Váňová, F. Schauer, K. Vlček, R. Jašek

Pages: 6-14

Abstract: In spite of the fact that remote laboratories and management of road intersection have been existing for at least three decades, virtually no attention has been devoted to the security of this new subject. The paper deals with the security of the data storage of the Datacenter (DTC)‚ with remote laboratories working under the Laboratory Management System (LMS) and to the construction of central management and analysis of collected data using dynamic modeling information obtained for centralized streamline the flow of traffic in the city.  Especially, the security risks for the data storage and corresponding data processing to ensure the operation of the data warehouse are described in detail. This article describes the newly proposed system in terms of communication data streams using the tools of the modern age, based on the proposed dynamically controlled system with real time feedback. DTC also will serve as the central system for analysis and storage of data from LMS and system for network of road junctions, therefore it is necessary to provide the service, as described in the following text article.

Title of the Paper: Frequency-Domain Equalization for SC-FDE in HF Channel


Authors: Xu He, Qingyun Zhu, Shaoqian Li

Pages: 1-5

Abstract: HF channel is a common multipath propagation resulting in frequency selective fading, SC-FDE can better resist frequency selective fading, but commonly used frequency domain equalization algorithm needs to get the value of channel estimation. In this paper, the research is applicable to SC-FDE in HF channel. The algorithm is after the conventional channel estimation algorithm, used the interpolation algorithm to reduce the number of pilot in the frame structure to improve the transmission efficiency,  use overlap FDE and MMSE-RISIC to improve the performance of communication system. Through the simulation prove that the algorithm has good use to estimate the channel and improve the spectrum utilization efficiency.