Volume 1, Issue 1, February 2010

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Optimization of MIMO detectors: Unleashing the multiplexing gain
[Full Text]

Nirmalendu Bikas Sinha, Department of ECE and EIE , College of Engineering & Management, K.T.P.P Township,  India
S.Chakraborty, Department of ECE, College of Engineering & Management, K.T.P.P Township, India
P. K. Sutradhar, Department of ECE, College of Engineering & Management, K.T.P.P Township, India
R. Bera,  S.M.I.T, SikkimManipal University, India
M.Mitra, Bengal Engineering and science University, India


Abstract— Multiple Input Multiple Output (MIMO) systems have recently emerged as a key technology in wireless communication systems for increasing both data rates and system performance. There are many schemes that can be applied to MIMO systems such as space time block codes, space time trellis codes, and the Vertical Bell Labs Space-Time Architecture (V-BLAST). This paper proposes a novel signal detector scheme called MIMO detectors to enhance the performance in MIMO channels. We study the general MIMO system, the general V-BLAST architecture with Maximum Likelihood (ML), Zero- Forcing (ZF), Minimum Mean- Square Error (MMSE), and Ordered Successive Interference Cancellation (SIC) detectors and simulate this structure in Rayleigh fading channel. Also compares the performances of MIMO system with different modulation techniques in Fading and AWGN channels. Base on frame error rates and bit error rates, we compare the performance and the computational complexity of these schemes with other existence model.Simulations shown that V-BLAST implements a detection technique, i.e. SIC receiver, based on ZF or MMSE combined with symbol cancellation and optimal ordering to improve the performance with lower complexity, although ML receiver appears to have the best SER performance-BLAST achieves symbol error rates close to the ML scheme while retaining the lowcomplexity nature of the V-BLAST.

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Co-channel Interference Cancellation for Space-Time Coded OFDM Systems Using Adaptive Beamforming and Null Deepening [Full Text]

Raungrong Suleesathira, Department of Electronic and Telecommunication Engineering, King Mongkut’s University, Bangkok, Thailand

Abstract—Combined with space-time coding, the orthogonal frequency division multiplexing (OFDM) system explores space diversity. It is a potential scheme to offer spectral efficiency and robust high data rate transmissions over frequency-selective fading channel. However, space-time coding impairs the system ability to suppress interferences as the signals transmitted from two transmit antennas are superposed and interfered at the receiver antennas. In this paper, we developed an adaptive beamforming based on least mean squared error algorithm and null deepening to combat co-channel interference (CCI) for the space-time coded OFDM (STC-OFDM) system. To illustrate the performance of the presented approach, it is compared to the null steering beamformer which requires a prior knowledge of directions of arrival (DOAs). The structure of space-time decoders are preserved although there is the use of beamformers before decoding. By incorporating the proposed beamformer as a CCI canceller in the STC-OFDM systems, the performance improvement is achieved as shown in the simulation results.

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Holistic Approach for Critical System Security: Flooding Prevention and Malicious Packet Stopping
[Full Text]

M.A. Alhabeeb, Faculty of Information Technology, Monash University, Melbourne, Australia
A.M Almuhaideb, Faculty of Information Technology, Monash University, Melbourne, Australia
P.D Le, Faculty of Information Technology, Monash University, Melbourne, Australia


Abstract— Denial of service attacks (DoS) can cause significant financial damages. Flooding and Malicious packets are two kinds of DoS attacks. This paper presents a new security approach which stops malicious packets and prevents flooding in the critical systems. New concepts of packet stamp a dynamic-multi-communication-point mechanism has been identified for this proposed approach to make the prevention of flooding attacks easier and the performing of malicious packet attacks harder. In addition, dynamic key encryption technique has been adapted as a part of the proposed approach to enhance its functionality.

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Design of Optimal Topology of Satellite-Based Terrestrial Communication Networks [Full Text]

Boris S. Verkhovsky, Department of Computer Science, New Jersey Institute of Technology, USA

AbstractTopological design of terrestrial networks for communication via satellites is studied in the paper. Quantitative model of the network cost-analysis minimizing the total transmission and switching cost is described. Several algorithms solving combinatorial problem of the optimal topology design based on binary partitioning, a minimax parametric search and dynamic programming are developed by the author and demonstrated with a numeric example. Analysis of average complexity of the minimax parametric search algorithm is also provided.

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Error Performance Analysis to Increase Capacity of A Cellular System Using SDMA [Full Text]

Md. M. Hossain, Department of Electronics and Communication Engineering, Khulna University, Bangladesh
J.Hossain, Axiata Limited,  Bangladesh(GSM operator)


Abstract— One of the biggest drawbacks of the wireless environment is the limited bandwidth. However, the users sharing this limited bandwidth have been increasing considerably.Space Division Multiple Access (SDMA) is a new technology by which the capacity of existing mobile communication systems can economically be increased. This paper has been presented how the capacity can be enhanced by using SDMA with smart antennas in mobile communications system. Based on Adaptive Antenna Array (AAA) technology the spatial dimension of the existing system is exploited by means of forming independent radio beams in each of the original channels. This paper analyses the comparison of average Bit Error Rate (BER) of SDMA and CDMA technique and the different ways in which SDMA can be introduced to increase the capacity of a cellular system. The probability of error is found for a standard omni directional base station antenna, and another set of curves is found for flat top beam having a directivity of 5.1dB. It is assumed that k separate flat top beams can be formed by base station and pointed each of the k users within the cell of interest. Noticing that for an average probability of error greater than 0.1 in a propagation path loss environment of n=4, the flat top beam will support 200 users, whereas the omni-directional antenna will support only 50 users. This increase the number of user is roughly equal to the directivity offered by the flat top beam system, and illustrates the promise
SDMA offers for improving capacity in wireless system. Here multipath fading is not considered.

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A new model for virtual machine migration in virtualized cluster server based on Fuzzy Decision Making
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M.Tarighi, Electrical & Electronics Engineering Department, University of AMIR KABIR, High Performance Computing Lab, Tehran,Iran
S.A.Motamedi, Electrical & Electronics Engineering Department, University of AMIR KABIR, High Performance Computing Lab, Tehran, Iran
S.Sharifian, Electrical & Electronics Engineering Department, University of AMIR KABIR, High Performance Computing Lab, Tehran, Iran

Abstract—In this paper, we show that performance of the virtualized cluster servers could be improved through intelligent decision over migration time of Virtual Machines across heterogeneous physical nodes of a cluster server. The cluster serves a variety range of services from Web Service to File Service. Some of them are CPU-Intensive while others are RAM-Intensive and so on. Virtualization has many advantages such as less hardware cost, cooling cost, more manageability. One of the key benefits is better load balancing by using of VM migration between hosts. To migrate, we must know which virtual machine needs to be migrated and when this relocation has to be done and, moreover, which host must be destined. To relocate VMs from overloaded servers to underloaded ones, we need to sort nodes from the highest volume to the lowest. There are some models to finding the most overloaded node, but they have some shortcomings. The focus of this paper is to present a new method to migrate VMs between cluster nodes using TOPSIS algorithm - one of the most efficient Multi Criteria Decision Making techniques- to make more effective decision over whole active servers of the Cluster and find the most loaded serversTo evaluate the performance improvement resulted from this model, we used cluster Response time and Unbalanced Factor.

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Performance Comparisons of ICA Algorithms to DS-CDMA Detection
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Sargam Parmar, U.V.Patel College of Engineering, Ganpat University, India
Bhuvan Unhelkar, school of Computing and Mathematics, University of Western Sydney,Australia


Abstract— Commercial cellular networks, like the systems based on DS-CDMA, face many types of interferences such as multi-user interference inside each sector in a cell to interoperate interference. Independent Component Analysis (ICA) has been used as an advanced preprocessing tool for blind suppression of interfering signals in DS-CDMA communication systems. The role of ICA is to provide an interference-mitigated signal to the conventional detection. This paper evaluates the performance of some major ICA algorithms like Cardoso’s joint approximate diagonalization of eigen matrices (JADE),
Hyvarinen’s fixed point algorithm and Comon’s algorithm to solve the symbol estimation problem of the multi users in a DSCDMA communication system. The main focus is on blind separation of convolved CDMA mixture and the improvement of the downlink symbol estimation. The results of numerical experiment are compared with those obtained by the Single User Detection (SUD) receiver, ICA detector and combined SUD-ICA detector.

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The Framework for Implementing ECommerce: The Role of Bank and Telecom in Bangladesh
[Full Text]

Ijaj Md. Laisuzzaman, Electronics and Communication Engineering Discipline, Khulna University,Bangladesh
Nahid Imran, Electronics and Communication Engineering Discipline,
Khulna University,Bangladesh
Abdullah Al Nahid, Electronics and Communication Engineering Discipline, Khulna University,Bangladesh
Md. Ziaul Amin, Electronics and Communication Engineering
Discipline, Khulna University,Bangladesh
Md. Abdul Alim,  Electronics and Communication
Discipline, Khulna University,Bangladesh

Abstract— In this paper, we describe an effective framework for adapting electronic commerce or e-commerce services in developing countries like Bangladesh. The internet has opened up a new horizon for commerce, namely electronic commerce (e-commerce). It entails the use of the internet in the marketing, identification, payment and delivery of goods and services. At present internet facilities are available in Bangladesh. Slowly, but steadily these facilities are holding a strong position in every aspects of our life. E-commerce is one of those sectors which need more attention if we want to be a part of global business. Bangladesh is far-far away to adapt the main stream of e-commerce application. Though government is shouting to take the challenges of e-commerce, but they do not take the right step, that is why e-commerce dose not make any real contribution in our socio-economic life. Here we propose a model which may develop the e-commerce infrastructure of Bangladesh.

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Effect of different substrates on Compact stacked square Microstrip Antenna
[Full Text]

Asok De is with the DelhiTechnological University, Delhi, India
N. S. Raghava is with the the DelhiTechnological University, Delhi, India
Sagar Malhotra is with the DelhiTechnological University, Delhi,India
Pushkar Arora is with the DelhiTechnological University, Delhi,India
Rishik Bazaz is with the DelhiTechnological University, Delhi,India

Abstract
— Selection of the most suitable substrate for a Microstrip antenna is a matter of prime importance. This is because many limitations of the microstrip antenna such as high return loss, low gain and low efficiency can be overcome by selecting an appropriate substrate for fabrication of the antenna, without shifting the resonant frequency significantly. The substate properties such as its dielectric constant, loss tangent have a pronounced effect on the antenna characteristics. Some of the critical properties that are to be taken care of while selecting a dielectric are homogeneity, moisture absorption and adhesion of metal- foil cladding. In this paper a comprehensive study of the effect of variation of substrate material on the antenna
properties has been presented.

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Limited Memory Prediction for Linear Systems with Different types of Observation
[Full Text]

Ha-ryong Song,
Gwangju Institute of Science and Technology, Gwangju, South Korea
Vladimir Shin, Gwangju Institute of Science and Technology, Gwangju, South Korea

Abstract
— This paper is concerned with distributed limited memory prediction for continuous-time linear stochastic systems with multiple sensors. A distributed fusion with the weighted sum structure is applied to the optimal local limited memory predictors. The distributed prediction algorithm represents the optimal linear fusion by weighting matrices under the minimum mean square criterion. The algorithm has the parallel structure and allows parallel processing of observations making it reliable since the rest faultless sensors can continue to the fusion estimation if some sensors occur faulty. The derivation of equations for error cross-covariances between the local predictors is the key of this paper. Example demonstrates effectiveness of the distributed limited memory predictor.

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FPGA Based Sinusoidal Pulse Width Modulated Waveform Generation for Solar (PV) Rural Home Power Inverter
[Full Text]

S. N. Singh, Department of Electronics Engineering, National Institute of Technology, NIT, Jamshedpur, India
A. K. Singh, Department of Electrical Engineering, National Institute of Technology, NIT, Jamshedpur, India

Abstract
With the increasing concern about global environmental protection and energy demand due to rapid growth of population in developing countries and the diminishing trend of resources of conventional grid supply, the need to produce freely available pollution free natural energy such as solar/wind energy has been drawing increasing interest in every corner of the world. In an effort to utilize these energies effectively through Power converter, a great deal of research is being carried out by different researchers / scientist and engineers at different places in the world to meet the increasing demand of
load. The study presents methodology to integrate solar (PV) energy (which is freely available in every corner of the world) with grid source and supplement the existing grid power in rural houses during its cut off or restricted supply period. In order to get consistency in supply a DG is also added as a standby source in the proposed integration of network. The software using novel Direct PWM modulation strategy and its soft control features extend the flexibility to control converter (inverter) parameters like voltage, frequency, number of samples of PWM pulses constituting sine-wave without changing any hardware configuration in the circuit. The system simulation of PWM Pulse generation has been done on a XILINX based FPGA Spartan 3E board using VHDL code. The test on simulation of PWM generation program after synthesis and compilation were recorded and verified on a prototype sample.


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Low-complexity Fusion Filtering for Continuous-Discrete Systems
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Seokhyoung Lee, Gwangju Institute of Science and Technology, Gwangju, South Korea
Vladimir Shin, Gwangju Institute of Science and Technology, Gwangju, South Korea

Abstract
—In this paper, low-complexity distributed fusion filtering algorithm for mixed continuous-discrete multisensory dynamic systems is proposed. To implement the algorithm a new recursive equations for local cross-covariances are derived. To achieve an effective fusion filtering the covariance intersection (CI) algorithm is used. The CI algorithm is useful due to its low-computational complexity for calculation of a big number of cross-covariances between local estimates and matrix weights. Theoretical and numerical examples demonstrate the effectiveness of the covariance intersection algorithm in distributed fusion filtering.

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Performance Analysis of Uplink & Downlink Transmission in CDMA System
[Full Text]

Md. M. Hossain, Electronics and Communication Engineering Discipline, Khulna University, Bangladesh
Md. M. Rahman is with the Electronics and Communication Engineering
Discipline, Khulna University, Bangladesh
Md. A. Alim is with the Electronics and Communication Engineering Discipline, Khulna University, Bangladesh


Abstract—CDMA is a multiple access method in which the user’s uses spread spectrum techniques and occupy the entire spectrum whenever they transmit. In wireless communication signal-to-noise ratio (SNR) is the very important parameter that influences the system performance. Any mode of mobile transmission is not free from channel impairment such as noise, interference and fading. This channel impairment caused signal distortion and degradation in SNR.Also there are differences between uplink (forward channel) and downlink (reverse channel).Along with these differences, both the links use different codes for chanellizing the individual users. This paper simulates the expressions for the pdfs of the SNR for both uplink and downlink transmission assuming that the system is operating at an average signal-to-noise ratio is 6dB per information bit.

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Dual-hop transmissions with fixed-gain relays over Generalized-Gamma fading channels
[Full Text]

K. P. Peppas, Laboratory of Mobile Communications, Institute of Informatics and Telecommunications,
National Centre for Scientific
Research, Athens, Greece
A. Mansour,
Department of Electronics, Computers, Telecommunications and Control, Faculty of Physics,
University
of Athens 15784, Greece
G. S. Tombras, Department of Electronics, Computers, Telecommunications and Control, Faculty of Physics,
University
of Athens 15784, Greece


AbstractIn this paper, a study on the end-to-end performance of dual-hop wireless communication systems equipped with fixed-gain relays and operating over Generalized-Gamma (GG) fading channels is presented. A novel closed form expression for the moments of the end-to-end signal-to-noise ratio (SNR) is derived. The average bit error probability for coherent and non-coherent modulation schemes as well as the end-to-end outage probability of the considered system are also studied. Extensive numerically evaluated and computer simulations results are presented that verify the accuracy of the proposed mathematical analysis.

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On Analysis and Evaluation of Multi-Sensory Cognitive Learning of a Mathematical Topic Using Artificial Neural Networks
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F.A. Al-Zahrani, Computer Engineering Department, Umm Al-Qura University, Makkah, Saudi Arabia
H.M. Mustafa, Computer Engineering Department, Albaha University, Egypt
A. Al-Hamadi, Institute for Electronics, Signal Processing and Communications (IESK) Otto-von-Guericke-University, Magdeburg

Abstract
— This piece of research belongs to the field of educational assessment issue based upon the cognitive multimedia theory. Considering that theory; visual and auditory material should be presented simultaneously to reinforce the retention of a mathematical learned topic, a carefully computer-assisted learning (CAL) module is designed for development of a multimedia tutorial for our suggested mathematical topic. The designed CAL module is a multimedia tutorial computer package with visual and/or auditory material. So, via suggested computer package, Multi-Sensory associative memories and classical conditioning theories are practically applicable at an educational field (a children classroom). It is noticed that comparative practical results obtained are interesting for field application of CAL package with and without associated teacher's voice. Finally, the presented study highly recommends application of a novel teaching trend aiming to improve quality of children mathematical learning performance.

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Analytical Evaluation of Unfairness Problem in Wireless LANs
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Ahmed Mohamedou, Department of Communications Technology and Networks, Universiti Putra Malaysia
Mohamed Othman, Department of Communications Technology and Networks, Universiti Putra Malaysia

Abstract—The number of users using wireless Local Area Network is increasing exponentially and their behavior is changing day after day. Nowadays, users of wireless LAN are using huge amount of bandwidth because of the explosive growth of some services and applications such as video sharing. This situation imposes massive pressure on the wireless LAN performance especially in term of fairness among wireless stations. The limited resources are not distributed fairly in saturated conditions. The most important resource is the access point buffer space. This importance is a result of access point being the bottleneck between two different types of networks. These two types are wired network with relatively huge bandwidth and wireless network with much smaller bandwidth. Also the unfairness problem is keep getting worse because of the greedy nature Transmission Control Protocol (TCP). In this paper, we conduct a comprehensive study on wireless LAN dynamics and proposed a new mathematical model that describes the performance and effects of its behavior. We validate the proposed model by using the simulation technique. The proposed model was able to produce very good approximation in most of the cases. It also gave us a great insight into the effective variables in the wireless LAN behavior and what are the dimensions of the unfairness problem.

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Hardware Implementation of TDES Crypto System with On Chip Verification in FPGA
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Prasun Ghosal, Department of Information Technology, Bengal Engineering and Science University, India
Malabika Biswas, Department of Information Technology, Bengal Engineering and Science University, India
Manish Biswas, Department of Information Technology, Bengal Engineering and Science University, India


Abstract—Security issues are playing dominant role in today’s high speed communication systems. A fast and compact FPGA based implementation of the Data Encryption Standard (DES) and Triple DES algorithm is presented in this paper that is widely used in cryptography for securing the Internet traffic in modern day communication systems. The design of the digital cryptographic circuit was implemented in a Vertex 5 series (XCVLX5110T) target device with the use of VHDL as the hardware description language. In order to confirm the expected behavior of these algorithms, the proposed design was extensively
simulated, synthesized for different FPGA devices both in Spartan and Virtex series from Xilinx viz. Spartan 3, Spartan 3AN, Virtex 5, Virtex E device families. The novelty and contribution of this work is in three folds: (i) Extensive simulation and synthesis of the proposed design targeted for various FPGA devices, (ii) Complete hardware implementation of encryption and decryption algorithms onto Virtex 5 series device (XCVLX5110T) based FPGA boards and, (iii) Generation of ICON and VIO core for the design and on chip verification and analyzing using Chipscope Pro. The experimental as well as implementation
results compared to the implementations reported so far are quite encouraging.

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Processing of Communication Signal Using Operational Transconductance Amplifier
[Full Text]

A. Roy, Department of Electronics and Telecommunication, Bengal Engineering and Science University, India
K. Ghosh, Department of Electronics & Communication Engineering, IERCEM Institute of Information Technology, India
S. Mondal,  CST Department,  Bengal Engineering and Science University, India
B. N. Ray, Department of Electronics and Telecommunication, Bengal Engineering and Science University, India


Abstract— This paper proposes a signal processing methodology of communication system and realized that circuits using operational transconductance amplifier (OTA). Two important classes of communication circuit, delta modulator and compander have been designed using that procedure. In the first implementation coded pulse modulation system is demonstrated which employ sampling, quantizing and coding to convert analog waveforms to digital signals while the second gives data compression and expansion in digital communication system. The proposed compander circuit is realized with operational transconductance amplifier and diode. Required power supply to operate the circuit is 3.5V. Performance of the circuits realized with OTAs has been demonstrated through SPICE simulation.

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Analyzing the Low Power Wireless Links for Wireless Sensor Networks
[Full Text]

Md. Mainul Islam Mamun, Department of Computer Science and Telecommunication Engineering,
Noakhali Science and Technology University, Bangladesh
Tarek Hasan-Al-Mahmud
Department of Computer Science and Telecommunication Engineering,
Noakhali Science and Technology University,
Bangladesh
Sumon Kumar Department of Computer Science and Telecommunication Engineering,
Noakhali Science and Technology University,
Bangladesh
Md. Zahidul Islam, Chonnam National University,South Korea

Abstract— There is now an increased understanding of the need for realistic link layer models in the wireless sensor networks. In this paper, we have used mathematical techniques from communication theory to model and analyze low power wireless links. Our work provides theoretical models for the link layer showing how Packet Reception Rate vary with Signal to Noise Ratio and distance for different modulation schemes and a comparison between MICA2 and TinyNode in terms of PRR.

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Challenges of Next-Generation Wireless Sensor Networks and its impact on Society
[Full Text]

Neelam Srivastava Department of Electronics Engineering, Institute ofEngineering & Technology. U. P. Technical University, India

Abstract—Wireless Sensor Networks (WSNs) have gained worldwide attention in recent years, particularly with the proliferation in Micro-Electro-Mechanical Systems (MEMS) technology which has facilitated the development of smart sensors. The paper discusses about classification of WSN and challenges of the Next Generation WSN. One of the major challenges of Next Generation WSN is reduction of power consumption. The two approaches are discussed: Ultra-Low-Power Networks and Energy Harvesting. The paper also discusses about some major applications as designing low cost secured Intelligent Buildings, In-Home Health care and Agriculture.