International Journal of Communications

E-ISSN: 1998-4480
Volume 6, 2012

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Issue 1, Volume 6, 2012

Title of the Paper: Performance Study of A Deep Space Communications System with Low-Density Parity-Check Coding under Solar Scintillation

Authors: Qi Li, Liuguo Yin, Jianhua Lu

Pages: 1-9

Abstract: The communication link is the only way for space probe to receive telecommand data from and return telemetry information to the control center on the earth. The design of deep space communication system has lots of challenging problems. For example, the solar scintillation effects can be significant for deepspace telecommunication links during superior solar conjunction. In this paper, the design and application of low-density parity-check (LDPC) coding scheme for deep space communication under solar scintillation condition is studied. In particular, the deep space communication channel under solar scintillation condition is modeled as a kind of Rician Channel that characterized by scintillation index, and the LDPC codes are optimized under such kind of channel mode to improve the bit-error rate (BER) performance. Simulation results reveal that compared with the convolutional codes the proposed LDPC codes could obtain 2.4 db and 2.5 db coding gain at 8.4 GHz (X-band) and 32 GHz (Ka-band), respectively. Moreover, simulation results also show that the deep space communication system with LDPC codes is much less sensitive to scintillation fading that that with convolutional codes.

Title of the Paper: Model Predictive Control for Networked Control Systems with Random Data Dropouts

Authors: Eva Miklovicova, Marian Mrosko

Pages: 10-17

Abstract: In this paper, the model predictive control for the networked control systems is proposed. The problem of data dropouts in the sensor controller link when the controller does not receive new feedback data is treated. As in predictive control design the sequence of future control actions up to a given horizon is calculated at each sampling time, the natural idea is to use not only the first control action, but also other terms of the control sequence, in case the sensor data at next sampling times are not available. From the implementation point of view there are two or more control laws (depending on the number of lost output samples) which are switched arbitrarily fast. A sufficient stability condition for this switched control system is derived using the concept of quadratic stability. The effectiveness of the proposed control strategy is demonstrated by control of a simple laboratory plant.

Title of the Paper: Wireless Network Effect on PI and Type-2 Fuzzy Logic Controller

Authors: Michal Blaho, Martin Urban, Peter Fodrek, Martin Foltin

Pages: 18-25

Abstract: With usage of data networks in control new area of research known as networked control systems was presented. Many communication medias and protocols can provide new possibilities in practical implementation. Professional solutions like PROFINET or IWLAN are followed with cheaper and popular networks like ZigBee or CAN bus. Recently, much attention has been paid to the wireless networks. ZigBee wireless networks are very popular for many advantages. Multiple control methodologies and practical applications have been developed for this kind of network. Applications must deal with negative effect of ZigBee network like network overload or packet dropout. In this paper we threated network disadvantages as uncertainty and we reduced them with type-2 fuzzy logic controller. We compared results with PI controller using Matlab and TrueTime environments.

Issue 2, Volume 6, 2012

Title of the Paper: Novel Design of WiMAX Multimode Interleaver for Efficient FPGA Implementation using Finite State Machine based Address Generator

Authors: Bijoy Kumar Upadhyaya, Salil Kumar Sanyal

Pages: 27-36

Abstract: In this paper, we present a novel and efficient technique to model WiMAX multimode interleaver using hardware description language. The hardware model is implemented on FPGA platform. Our proposed interleaver consists of finite state machine based address generator and optimized FPGA’s embedded resource based memory. The finite state machine based address generator of the interleaver shows better performance in terms of maximum operating frequency, and FPGA resource utilization compared to existing FPGA techniques. Use of FPGA’s embedded memory offers advantages like reduced access time, lesser real estate occupancy of circuit board and lower power consumption than external memory based techniques. Estimated power consumption and software simulation of both address generator and the complete interleaver are also provided. Our design is truly based on IEEE 802.16e standard where all the code rates and modulation schemes for WiMAX have been incorporated. In addition our approach supports computation of interleaver addresses dynamically.

Title of the Paper: Design and Analysis of Wideband Modified Circular Patch Microstrip Antennas for Multiple Band Operation

Authors: S. R. Chowdhury, S. Basu

Pages: 37-46

Abstract: This paper presents the design and analysis of a modified wideband circular patch microstrip antenna to enhance the impedance bandwidth of a conventional circular patch. Ansoft Designer V2 is employed to analyze the performance of the proposed antenna structure with single coaxial feed as well as with microstrip feed at different positions of this modified structure. The proposed antenna shows dual 10dB impedance-bandwidth of about 38% and 15% having center frequencies at 4GHz and 12GHz respectively with coaxial feed. The same structure shows 10dB impedance-bandwidth of about 14% and 79% for dual resonant frequencies at 8 GHz and 18 GHz respectively for a specific position of the microstrip feed and 35% at 22 GHz for another position of the microstrip feed which is perpendicularly oriented with respect to the first one. The patch structure is further modified by introducing rectangular finite ground plane of dimension 50mm X 50mm for both coaxial fed and microstrip fed modified circular patch and its effect on different antenna parameters are studied.

Title of the Paper: Product Placement Industry in the Czech Republic as Embedded Marketing

Authors: Jan Kramoliš, Martina Drábková

Pages: 47-54

Abstract: Product placement has been around in some extent for many years. After June 2010, there is a new field of view legal aspect in the Czech Republic. Some placement involves more subliminal placement of the specific product within a scene or visual. Others includes spoken lines that make mention of the products or its brand. As advertisers have become concerned about the effectiveness of traditional TV advertising, they have turned to alternative approaches such as product placement, so we speak about “TV advertising x Product placement cannibalization”. Marketing experts have inconsistent opinions on product placement. Some of them consider it to be a new marketing tool while others perceive it to be a new type of advertisement. This article explains the role of product placement and describes its current situation on the Czech market.

Title of the Paper: One-Wire Line System for Transmitting Energy or Information

Authors: Michael Bank

Pages: 55-63

Abstract: There are three well known types of wire lines for transmitting electrical energy or information: the ordinary two wires line (below A-Line); the so-called single-wire line, where ground is in the role of the second wire; three phase system. This article presents a new electric transmission system named B-Line which uses one line only and does not use ground. One-Wire method is working on all frequencies of power and communication systems. The article indication.

Title of the Paper: Phase Diversity Method in Mobile Communication Systems

Authors: Michael Bank, Y. Barish, S. Tapuchi, Miriam Bank, B. Hill, M. Haridim

Pages: 64-71

Abstract: Phase diversity techniques are used in many communication systems, including PAL TV system, FBS method, and the Alamouty algorithm for MIMO. Phase diversity algorithms have proved effective in mitigating phase distortion in wireless channels. In this article we present a new method of phase diversity processing that is based on phase arithmetical summing.

Title of the Paper: Performance of Spectrum Sensing and Optimization Based on User Selection in Cognitive Radio

Authors: Yang Ou, Yi-Ming Wang

Pages: 72-79

Abstract: The paper first proposes a fast novel spectrum sensing algorithm for cognitive radios based on cyclic autocorrelation. When only the existence of primary users in noise is detected, special cyclic frequency can be choosed to sense, which will significantly reduce the computational cost in applying the cyclostationarity detection. The paper also proposes to select the users with good detection performance for cooperative sensing so as to improve sensing sensitivity. It demonstrates that the throughput of CR system is also improved by user selection.

Title of the Paper: Highly Effective Handset Antenna

Authors: M. Bank, M. Haridim, V. Tsingouz, Z. Ibragimov

Pages: 80-87

Abstract: It is shown that the MB antenna, which uses the handset PCB as the radiating element, is equivalent to a full-wave dipole, i.e. each arm is half-wavelength long. This enhanced length of the dipole, and hence its improved properties, is achieved due to the fact that in the MB antenna the radiating arms are short-circuited at their ends. This approach allows increasing the antenna's gain by 3dB, as compared to the conventional dipole, while removing the need for a separate antenna to be installed on the PCB.

Issue 3, Volume 6, 2012

Title of the Paper: Orthogonal MIMO Antennas for Compact Cellular Handsets

Authors: M. Bank, K. Slupenko, M Haridim, V. Tsingouz

Pages: 89-97

Abstract: We propose a novel compact MIMO antenna system for small handsets, based on two different types of antennas –a small loop and the MB antenna. The MB antenna is an enhanced dipole antenna, which can be implemented as internal antenna in a compact cellular handset. Similar to conventional dipole, MB is an electrical antenna; and the small loop is a magnetic antenna. It is shown that using these antenna one can create a compact MIMO system, with small mutual coupling between the antennas, even when the distance between them is smaller than λ/3. We also present a new method for increasing the radiation efficiency of small loop antennas at frequencies higher than 470MHz. Simulations results show that the mutual coupling between MB and small loop antennas is low.

Title of the Paper: A Study of Creating Technology Education Course for Cloud Computing

Authors: Lung-Hsing Kuo, Jui-Chen Yu, Hsieh-Hua Yang, Wen-Chen Hu, Hung-Jen Yang

Pages: 98-108

Abstract: The purpose of this study was to identify the content structure and learning experience for integrating cloud computing into high-school learning offered by the High-Scope Project. For coping with new contents brought by fast advancing technology, education system should provide ways to integrating that new information of emerging technology into our curriculum for preparing students with up-to-date knowledge. There is a need to identify learning goals, the scope and structure of integrating cloud computing into formal learning. The selected learning experience of cloud computing were identified by following the theory of technology education. By applying the investigation method, the content was verified by invited professionals. Their evaluation resulted significant agreement between selected contents and technology principles. The reliability between evaluators was 0.87.

Title of the Paper: Applying Computerized Digitizing Technique to Explore the POP Album Cover Historical Reflections

Authors: Li-Min Chen, Lung-Hsing Kuo, Hung-Jen Yang

Pages: 109-119

Abstract: The purpose of this study was to demonstrate the application of computerized digitizing process on exploring the historical reflection of the old pop album cover. Through digitizing technique, the characteristics of old pictures could be measured. Based on the color attributes of pop album cover, a diachronic study was conducted. It was argued that the denotation is significant related to the color attributes and the connotation is not necessary significant related to the color attributes. The population of this study was those pop albums published from 1970 to 2000. The sampled representative pop album covers were collected and scanned into digital files for both color attribute analysis and content analysis. The denotation and color attributes of each sampled album cover were also identified for statistical test. A logit regression was used to predict denotation of pop album cover from mean value of color channel Red, Green, and Blue. The C5.0 model was used to build a rule set and a decision tree for further illustrate the relation between color attribute and denotation.

Title of the Paper: Secure and Redundant Public Safety Communication Network for Public Protection and Disaster Relief (PPDR) Organizations

Authors: Jari Ahokas, Jyri Rajamäki, Ilkka Tikanmäki

Pages: 120-127

Abstract: European Public Protection and Disaster Relief (PPDR) organizations have similar needs for communications. A common network for PPDR creates synergy and makes interoperability possible. This paper presents a new highly redundant and secure data communications network solution for Public Safety Communications (PCS). The solution is decentralized and communications paths are redundant. Even if the network layer is shared with different users or different use purposes all communications remains secured and access controlled. Distributed Systems intercommunication Protocol (DSiP) offers all of these features in a single solution. This enables building cyber-secure data network for PPDR organizations. Even though the communications channels are reliable and secured, there are still some issues to be considered. This paper introduces these issues and offers solutions for these challenges.

Title of the Paper: Compatibility Analysis for Wireless Systems in VHF/UHF Bands with Geographic Information

Authors: Kyoung-Whoan Suh, Jeong-Seok Jang, Jung-Ho Ahn

Pages: 128-135

Abstract: By using radio propagation predictions of Rec. ITU-R P.1546 combined with geographic information, formulations for field calculation and interference analysis are presented in the VHF and UHF bands. To illustrate some computational results for the given system parameters, virtual and real geographic data are taken into account. Performance and protection ratio including the net filter discrimination are reviewed for the fixed wireless system interfered with the radar operated at the co-channel frequency as well as frequency offset. Interference effect of the victim receiver has been also examined by varying radar beam direction over azimuth and elevation angles. The developed methodology can be actually applied to evaluate interoperability between wireless systems under the net-centric warfare environment.

Title of the Paper: Path Loss Analyses in Tunnels and Underground Corridors

Authors: Andrej Hrovat, Gorazd Kandus, Toma? Javornik

Pages: 136-144

Abstract: This paper presents the applicability of commercial and license free simulation tools for path loss calculations in tunnels and underground corridors. WinProp simulation tool has been selected for path loss calculation based on deep study of simulation tools performance, implemented radio propagation algorithms, results representation and representation and modeling of the propagation environment. A set of simulations at various frequencies were performed for tunnels with standard cross-sectional shapes, dimensions, material properties and in addition with presence of the obstacles preventing radio wave propagation along tunnel. The signal frequency and dimension of the tunnel cross section have considerable impact on path loss, while the tunnel cross shape and the transmitter/receiver position does not have it. The results were evaluated by four-slope empirical path loss model and measurement results performed in two different tunnels. The comparison confirmed the adequacy of the simulation tool for performing the path loss calculation and communication range determination in different tunnels and corridors.

Issue 4, Volume 6, 2012

Title of the Paper: Wireless Cellular Systems Performance Improvement Based on Neural Network

Authors: Omar R. Daoud, Mohammed M. Ali

Pages: 145-152

Abstract: In this paper, a neural network (NN) part has been imposed to overcome a previously mitigated drawback that is found in Orthogonal Frequency Division Multiplex technology (OFDM) systems. In the learning process we make use of the results obtained from the previously published work to reduce the Peak to Average Power Ratio (PAPR) problem based on different linear coding techniques. The proposed technique shows that an improvement in the OFDM technology performance has been achieved based on reducing the system’s complexity. Moreover, the reduction percentage of the PAPR compared to the previously published one; which combats the PAPR based on Low Density Parity Check (LDPC), turbo coding and convolutional coding has been attained exactly. Our simulation results show that 15% reduction in PAPR over current values in the literature can be achieved depending on the system’s type. This is in addition to that the use of NN reduces the overall OFDM system's complexity. This is because that in the proposed technique the system does not need to send extra data to recombine the processed OFDM symbols at the receiver side. Thus, the performance improvement could be attained.

Title of the Paper: Internet Piracy from a Digital Consumer’s Viewpoint

Authors: Dimitrios Xanthidis, Eisa Aleisa

Pages: 153-165

Abstract: It goes without saying that Internet piracy in several countries has taken massive proportions, causing serious conflict between social groups and the respective industries. The reasons behind this rapid and, seemingly, uncontrolled phenomenon is investigated aiming to aid the industry in their search for common grounds with these communities so as to, maybe, use this otherwise illegal practice for the industry’s benefit but the social welfare as well. The study provides and briefly explains the arguments of both sides i.e. the digital consumers/pirates and the industry in an effort to help realize that this is not a problem with an easy solution since there are many parameters to consider and account for which are not clearly pro or against one of the two parties. The conclusion is that the problem is mainly the result of a big gap between the industry’s and the digital consumers’ perception of the real commercial value of digital content in different forms.

Title of the Paper: Shooting and Bouncing Ray Approach for 4G Radio Network Planning

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

Pages: 166-174

Abstract: Radio signal propagation prediction plays an essential role in planning of modern broadband mobile radio networks. While the less accurate statistical models predict only the path loss, the more precise ray tracing techniques enable computation of additional parameters, e.g. the mean delay and the delay spread, which are significant for the 4G network planning. The existing ray tracing methods are mainly applied in the indoor and narrow urban environments. In this paper, an open-source solution for propagation prediction with a ray tracing method in the open urban and rural areas is presented. The emphasis is on the implementation of a computationally efficient procedure, which is divided into two separately optimized problems, tessellation and ray tracing. Ray tracing is implemented by applying an improved shooting and bouncing ray (SBR) approach. The efficiency of the implementation is analysed in terms of computational complexity and results accuracy. The simulation results show that by applying a tessellation optimization technique the processing time is reduced up to 50%. The improved SBR ray tracing approach has been incorporated in the existing open source radio planning tool GRASS-RaPlaT.