Volume 2, Issue 1, April 2010

Measuring Data and VoIP Traffic in WiMAX Networks  [Full Text]

Iwan Adhicandra, Department of Information Engineering, University of Pisa, Via Caruso 16, 56127 Pisa, Italy

Abstract—Due to its large coverage area, low cost of deployment and high speed data rates, WiMAX is a promising technology for providing wireless last-mile connectivity. Physical and MAC layer of this technology refer to the IEEE 802.16e standard, which defines 5 different data delivery service classes that can be used in order to satisfy Quality of Service (QoS) requirements of different applications, such as VoIP, videoconference, FTP, Web, etc. The main aim of the paper is to examine a case of QoS deployment over a cellular WiMAX network. In particular, the paper compares the performance obtained using two different QoS configurations differing from the delivery service class used to transport VoIP traffic, i.e. UGS or ertPS. Results indicate that for delay-sensitive traffic that fluctuates beyond its nominal rate, having the possibility to give back some of its reserved bandwidth, ertPS has the advantage to permit the transmission of BE traffic.

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Optimal Crosstalk Detection and Localization Method for Optical Time Division Multiplexed Transmission Systems
[Full Text]

F.A. Ahmed Jedidi, CES Laboratory, National School of Engineering, University of Sfax, Tunisia
S.B. Mohamed Abid, CES Laboratory, National School of Engineering, University of Sfax, Tunisia


Abstract—
All-Optical Network (AON) is a network where the user-network interface is optical and the data does undergo optical to electrical conversion within the network. AONs are attractive because they promise very high rates, flexible switching and broad application support. There are two technologies for AON: Wavelength Division Multiplexed (WDM) and Optical Time Division Multiplexed (OTDM). OTDM transmission systems are becoming increasingly important as one of the key technologies satisfying the growing demand for large capacity optical networks. Although OTDM has several advantages in
terms of operation system, such as natural accommodation of higher bit rate payloads, it introduces many security vulnerabilities, which do not exist in traditional networks. One of the serious problems with OTDM is the fact that optical crosstalk is additive, and thus the aggregate effect of crosstalk over a whole all-optical network (AON) may be more nefarious than a single point of crosstalk. This is because crosstalk can spread rapidly through the network, causing additional awkward failures and triggering multiple undesirable alarms. This results in the continuous monitoring and identification of the
impairments becoming challenging in the event of transmission failures. In this paper we propose a novel approach for detecting and localizing crosstalk in OTDM transmission systems that can participate in some tasks for fault management in optical network.


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Investigation on QoS of Campus-wide WiFi Networks
[Full Text]

Norrozila Sulaiman, Universiti Malaysia Pahang, Malaysia
Che Yahaya Yaakub, Universiti Malaysia Pahang, Malaysia


Abstract—
WiFi is widely implemented in campus wide including administrative, teaching and student’s accommodation. Wireless communications are associated with interconnect devices which includes cellular networks, infrared, bluetooth and WiFi enabled devices. It involves mobility and freedom of assessing information anytime and anywhere. A study on WiFi networks in a campus environment is presented in this paper. The aim of the research was to investigate the connectivity problems to WiFi networks. The study includes WiFi performance analysis as well as network auditing. Channel overlapping and saturation condition were some of the problems encountered. Different types of software were used for analyzing the results.

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Modelling and Implementation of ITWS: An ultimate solution to ITS
[Full Text]

Nirmalendu Bikas Sinha, Department of ECE and EIE , College of Engineering & Management, Kolaghat, K.T.P.P Township, India
Manish sonal, Department of ECE, College of Engineering & Management, Kolaghat, K.T.P.P Township, India
Makar Chand Snai, Department of ECE, College of Engineering & Management, Kolaghat, K.T.P.P Township, India
R. Bera, S.M.I.T, SikkimManipal University, India
M.Mitra, Bengal Engineering and science University, India

Abstract— Casualties due to traffic accidents are increasing day by day. Think of this message being displayed on your computer screen while you were driving “there’s a possibility of collision with a car in the next few minutes if you go on driving with this speed and direction”. Our research is intended towards developing collision avoidance architecture for the latest Intelligent Transport System. The exchange of safety messages among vehicles and with infrastructure devices poses major challenges. Specially, safety messages have to be adaptively distributed within a certain range of a basically unbounded system. These messages are to be well coordinated and processed via different algorithms. The purpose of the paper is to discuss the ITWS (intelligent transportation warning system) ,we have discussed the Assisted Global Positioning System(AGPS) system providing additional positioning information at variable conditions. We have also discussed study the Data fusion and kalaman filter in details. The performance of kalman filter and output are discussed. Hardware realization of this model is achieved through software defined radio (SDR).

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Modelling and Design of a Microstrip Band-Pass Filter Using Space Mapping Techniques
[Full Text]

S. Tavakoli, Faculty of Electrical and Computer Eng, University of Sistan and Baluchestan, Iran
M. Zeinadini, Faculty of Electrical and Computer Eng, University of Sistan and Baluchestan, Iran
S. Mohanna, Faculty of Electrical and Computer Eng, University of Sistan and Baluchestan, Iran

Abstract—Determination of design parameters based on electromagnetic simulations of microwave circuits is an iterative and often time-consuming procedure. Space mapping is a powerful technique to optimize such complex models by efficiently substituting accurate but expensive electromagnetic models, fine models, with fast and approximate models, coarse models. In this paper, we apply two space mapping, an explicit space mapping as well as an implicit and response residual space mapping, techniques to a case study application, a microstrip band-pass filter. First, we model the case study  application and optimize its design parameters, using explicit space mapping modelling approach. Then, we use implicit and response residual space mapping approach to optimize the filter's design parameters. Finally, the performance of each design methods is evaluated. It is shown that the use of above-mentioned techniques leads to achieving satisfactory design solutions with a minimum number of computationally expensive fine model evaluations.

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Clustering of Content Supporting Computer Mediated Courseware Development
[Full Text]

G. M. M. Bashir, Department of Computer and Communication Engineering, Patuakhali Science and Technology University, Bangladesh
M. J. Hossain,  Department of Computer and Information Technology, Patuakhali Science and Technology University, Bangladesh
M. R. Karim, Bangladesh Bank, Bangladesh

Abstract—
Computer Mediated Courseware (CMC) has been developed so far for individual courses considering single or multiple text books. A group of courseware can be developed by using multiple text books and in this case, it is a requirement to cluster the contents of different books to form a generalized clustered content. No work has been found to develop courseware applying generalized clustered content. We have proposed a clustering of content supporting computer mediated courseware development based on data mining techniques to construct a hierarchical general structure of a group of courseware combining the individual structure of a set of books. The clustering will help the courseware developer to dynamically allocate contents to
develop different courses using a group of books. The authors have applied this methodology for different level of courses on database. The methodology is generalized and can be applied to any other courses.


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Wireless sensors networks MAC protocols analysis
[Full Text]

L. Chaari, Department of Electronic and Information Technology Laboratory (LETI), Sfax National Engineering School, Tunisia
L. Kamoun, Department of Electronic and Information Technology Laboratory (LETI), Sfax National Engineering School, Tunisia


Abstract—Wireless sensors networks performance are strictly related to the medium access mechanism. An effective one, require non-conventional paradigms for protocol design due to several constraints. An adequate equilibrium between communication improvement and data processing capabilities must be accomplished. To achieve low power operation, several MAC protocols already proposed for WSN. The aim of this paper is to survey and to analyze the most energy efficient MAC protocol in order to categorize them and to compare their performances. Furthermore we have implemented some of WSN MAC protocol under OMNET++ with the purpose to evaluate their performances.

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VHDL Implementation of different Turbo Encoder using Log-MAP Decoder
[Full Text]

Akash Kumar Gupta, Department of Electronics and Communication, Birla Institute of Technology, India
Sanjeet Kumar, Department of Electronics and Communication, Birla Institute of technology, India

Abstract— Turbo code is a great achievement in the field of communication system. It can be created by connecting a turbo encoder and a decoder serially. A Turbo encoder is build with parallel concatenation of two simple convolutional codes. By varying the number of memory element (encoder configuration), code rate (1/2 or 1/3), block size of data and iteration, we can achieve better BER performance. Turbo code also consists of interleaver unit and its BER performance also depends on interleaver size. Turbo Decoder can be implemented using different algorithm, but Log –MAP decoding algorithm is less computationaly complex with respect to MAP (maximux a posteriori) algorithm, without compromising its BER performance, nearer to Shannon limit. A register transfer level (RTL) turbo encoder is designed and simulated using VHDL (Very high speed integrated circuit Hardware Description Language). In this paper VHDL model of different turbo encoder are implemented using Log MAP decoder and its performance are compared and verified with corresponding MATLAB simulated results.

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Video shot boundary detection using motion activity descriptor
[Full Text]

Abdelati Malek Amel, National school of engineers of monastir, Tunisia
Ben Abdelali Abdessalem, High Institute of Informatics and Mathematics of Monastir, Tunisia
Mtibaa Abdellatif, National School ef engineers, Monastir, Tunisia

Abstract—This paper focus on the study of the motion activity descriptor for shot boundary detection in video sequences. We interest in the validation of this descriptor in the aim of its real time implementation with reasonable high performances in shot boundary detection. The motion activity information is extracted in uncompressed domain based on adaptive rood pattern search (ARPS) algorithm. In this context, the motion activity descriptor was applied for different video sequence.

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Performance Evaluation of SCM-WDM System Using Different Linecoding
[Full Text]

Md. Shamim Reza, Dept. of Electrical and Electronic Engineering, Bangladesh University of Engineering and Technology,Bangladesh
Md. Maruf Hossain, Dept. of Electrical and Electronic Engineering, American International University of Bangladesh, Bangladesh
Adnan Ahmed Chowdhury, Dept. of Electrical and Electronic Engineering, International Islamic University of Chittagong, Bangladesh
S. M. Shamim Reza, Dept. of Electrical and Electronic Engineering, International Islamic University of Chittagong, Bangladesh
Md. Moshiur Rahman, Dept. of Electrical and Electronic Engineering, International Islamic University of Chittagong, Bangladesh


Abstract
This paper investigates the theoretical performance analysis for a subcarrier multiplexed (SCM) wavelength division multiplexing (WDM) optical transmission system in presence of optical beat interference (OBI) which occurs during the photo detection process. We have presented a comparison for improving the performance of SCM-WDM system in presence of OBI. Non-return-to zero (NRZ), Manchester and Miller code (MC) line coding are used for performance investigation of SCM-WDM system. A suitable signal bandwidth is selected and 200 KHz is considered as channel bandwidth. Power spectrum of signal and cross component for those line coding are analyzed. Comparison results are evaluated in terms of signal to OBI ratio for the three linecoding schemes which is called signal to interference ratio (SIR). It is found that there is a significant increase in the SIR by employing Miller code compared to NRZ and Manchester for the same data rate. For example, for a number of subcarriers of 10, the achievable SIR is about -24 dB for Miller coded system compared to -46 dB for NRZ coded system and -49 dB for Manchester coded system. The results are found to be satisfactorily agreed with the expected results.

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Optimum Design of a 4x4 Planar Butler Matrix Array for WLAN Application
[Full Text]

Wriddhi Bhowmik, Department of ECE, Birla Institute of Technology, India
Shweta Srivastava, Department of ECE, Birla Institute of Technology,India


Abstract— In recent years, high-speed wireless communication is in vogue. In wireless communication systems, multipath fading, delay and interference
occurres by reflection or diffraction. In a high-speed wireless communication, it becomes a necessary to separate desired signal from delay or interference signal. Thus to overcome these problems Smart antenna systems have been developed. Basically there are two types of smart antenna systems, one is Switched beam system and another Adaptive array system.This paper presents the optimum design of a 4x4 plannar Butler matrix array as a key component of a switched beam smart antenna system, operating at 5.2 GHz for WLAN with a dielectric substrate, FR4 of er =4.9 and h=1.6mm. Conception details, simulation results and measurements are also given for the components (microstrip antenna, hybrid couplers, cross-coupler, phase shifter) used to implement the matrix. In this dissertation, mathematical calculations for all the components using MATLAB is done and then every individual component is designed using the commercial software SONNET. Then these entire components have been combined on a single substrate and simulated using SONNET.


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Towards Hardware implementation of video applications in new telecommunications devices
[Full Text]

Lamjed Touil, Laboratoire EμE, Faculté des Sciences FSM, Monastir, Tunisia
Abdessalem ben Abdelali, Laboratoire EμE, Faculté des Sciences FSM, Monastir,
Tunisia
Abdellatif Mibaa, Laboratoire EμE, Faculté des Sciences FSM. Monastir, Tunisia
Elbey Bourennane, Laboratory LE2I University of Burgundy, Dijon, France


Abstract—Among the areas, most demanding in terms of calculation is the telecommunication and video applications are now included in several telecommunication devices such as set-top boxes, mobile phones. Embedded videos applications in new generations of telecommunication devices need a processing capacity that can not be achieved by the conventional processor, to work around this problem the use of programmable technology has a lot of interest. First, Field Programmable Gate Arrays (FPGAs) present many performance benefits for real-time image processing applications. The FPGA structure is able to exploit spatial and temporal parallelism. In this paper, we present a new method for implementation of the Color Structure Descriptor
(CSD) using the FPGA circuit. In fact the (CSD) provides satisfactory image indexing and retrieval results among all colorbased descriptors in MPEG-7. But the real time implementation of this descriptor is still having problems. In this paper we propose a method for adapting this descriptor for possible implementation under the constraints of the video processing in real time. We have verified the real-time implementation of the (CSD) with an image size of 120*80 pixels.


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In Quest of the Better Mobile Broadband Solution for South Asia Taking WiMAX and LTE into Consideration
[Full Text]

Nafiz Imtiaz Bin Hamid, Department of Electrical and Electronic Engineering (EEE), Islamic University of Technology (IUT), Bangladesh
Md. R. H. Khandokar, School of Engineering and Computer Science. Independent University, Bangladesh
Taskin Jamal, Electrical and Electronic Engineering Department, University of Asia Pacific, Dhanmondi, Dhaka-1209, Bangladesh
Md. A. Shoeb, Electrical and Electronic Engineering Department, Stamford University, Siddeswari, Dhaka-1217, Bangladesh
Md. Zakir Hossain, Radio Access Network (RAN) Department, Qubee. Augure Wireless Broadband Bangladesh Limited, Bangladesh


Abstract— Internet generation is growing accustomed to having broadband access wherever they go and not just at home or in the office, which turns mobile broadband into a reality. This paper aims to look for a suitable mobile broadband solution in the South Asian region through comparative analysis in various perspectives. Both WiMAX and LTE are 4G technologies designed to move data rather than voice having IP networks based on OFDM technology. Proving competency in various significant aspects WiMAX and LTE already have made a strong position in telecommunication industry. Again, because of certain similarities in technology; they aren’t like technological rivals as of GSM and CDMA. But still they are treated as opponents and viewed as a major threat in case of the flourishing of each other. Such view point is surely not conducive for getting the best out of them. In this paper various aspects and applications of WiMAX and LTE for deployment have been analyzed. South Asia being the residence of an enormous number of people presents an exciting opportunity for mobile operators, developers and internet service providers. So, every consideration that has been made here also correlates successfully with south Asia i.e. how mass people of this region may be benefited from it. As a result, it might be regarded as a good source in case of making
major BWA deployment decisions in this region. Besides these, it also opens the path for further research and thinking in this issue.


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Mobility Prediction in Wireless Ad Hoc Networks using Neural Networks
[Full Text]

Heni Kaaniche, Faculty of Sciences of Sfax, Tunisia
Farouk Kamoun, Computer Science School of the University of Manouba, Tunisia

Abstract—Mobility prediction allows estimating the stability of paths in a mobile wireless Ad Hoc networks. Identifying stable paths helps to improve routing by reducing the overhead and the number of connection interruptions. In this paper, we introduce a neural network based method for mobility prediction in Ad Hoc networks. This method consists of a multi-layer and recurrent neural network using back propagation through time algorithm for training.

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Evaluation of Burst Loss Rate of an Optical Burst Switching (OBS) Network with Wavelength Conversion Capability
[Full Text]

Md. Shamim Reza, Dept. of Electrical and Electronic Engineering, Bangladesh University of Engineering and Technology,Bangladesh
Md. Maruf Hossain, Dept. of Electrical and Electronic Engineering, American International University of Bangladesh, Bangladesh
Satya Prasad Majumder, Dept. of Electrical and Electronic Engineering, Bangladesh University of Engineering and Technology, Bangladesh

Abstract – This paper presents a new analytical model for calculating burst loss rate (BLR) in a slotted optical burst switched network. The analytical result leads to a framework which provides guidelines for optical burst switched networks. Wavelength converter is used for burst contention resolution. The effect of several design parameters such as burst arrival probability, wavelength conversion capability, number of slots per burst and number of wavelengths is incorporated on the above performance measure. We also extend the analytical result of BLR for different types of service classes where each service class has a reserved number of wavelengths in a network with fixed number of wavelengths. We also introduce an algorithm to calculate the resultant number of wavelength for each service classes depending on the various scenarios.

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Performance Evaluation of Wavelength Routed Optical Network with Wavelength Conversion
[Full Text]

V. J. Gond, Department of Electronics and Communication, Maulana Azad National Institute of Technology, India
A. Goel, Department of Electronics and Communication, Maulana Azad National Institute of Technology, India


Abstract – The rapid development of telecommunication networks is driven by user demands for new applications and advances in technologies. The explosive growth of the internet traffic is due to its use for collecting the information, communication, multimedia application, entertainment, etc. These applications are imposing a tremendous demand for bandwidth capacity on telecommunication network. The introduction of fiber optics had proved to meet the huge demand of bandwidth. These requirement can be meet by all optical network which is capable of transmitting enormous data at very high speed, around 50 Tera bits per seconds (Tbps) A wavelength conversion technique is addressed in this paper to reduced the blocking probability in wavelength routed networks. It is seen that the blocking probability of traffic requests decreases as the wavelength conversion factor increases. We explode the possibility for network with different size with variation in wavelength per link. In this work the evaluation of wavelength routed optical network with varying number of wavelength converters, different traffic types are carried out and results are shown that the blocking probability is minimum with 50% to 60% wavelength convertible nodes. Wavelength convertible nodes more than 60% are not showing much effect on reduction in blocking probability rather it results in increase in overall cost of network.

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Conception and FPGA implementation of IEEE 802.11s mesh network MAC layer transmitter
[Full Text]

L. Chaari, Department of Electronic and Information Technology Laboratory (LETI) at Sfax National Engineering School Tunisia
L. Kamoun, Department of Electronic and Information Technology Laboratory (LETI) at Sfax National Engineering School Tunisia


Abstract— This paper proposes, a hardware implementation of Wireless Mesh Networks (WMN) medium Access Controller (MAC) layer transmitter. In the literature a lot of works are focused on WMN routing protocol as well as performance analysis and software integration of WMN units, however few works deals with WMN hardware implementation. In this field our contribution is to conceive and to implements on FPGA a WMN MAC transmitter module. Our implementation, written in hardware description language (HDL) is based on the IEEE 802.11 s standard. The hardware implementation retains a good
performance in speed.