Telfor Journal Vol.1 No.1 (2009)

Content

Editorial HyperLink
Editor-in-Chief: Prof. Dr Đorđe Paunović

Comparative Analysis of Packet Scheduling Schemes for HSDPA Cellular Networks

T. Janevski and K. Jakimoski
Topic:
Telecommunications Networks
Abstract
In this paper we present comparison analysis for packet scheduling algorithms for HSDPA (High Speed Downlink Packet Networks). In particular, we analyze the round robin, max C/I and FCDS packet scheduling algorithms in HSDPA by comparing the average throughput, delay and fairness of the users, changing the number of the users in pedestrian and vehicular environment. The results have showed that the number of the users in a given coverage area is very important when choosing which packet scheduling algorithm for HSDPA networks. These results will be very useful for choosing the adequate scheduling algorithm in HSDPA network with aim to satisfy the desired quality of service for the mobile users.
Keywords
HSDPA, Mobile Networks, Scheduling.
Full Text
HyperLink Comparative Analysis of Packet Scheduling Schemes for HSDPA Cellular Networks
Page(s)
2-5

Reinforcement Learning for Dynamic Spectrum Management in WCDMA

N. Vučević, J. Pérez-Romero, O. Sallent, and R. Agustí
Topic:
Telecommunications Networks
Abstract
Low use of licensed spectrum imposes a need for the advanced spectrum management for wise spectrum usage with the release of unneeded frequency bands for the secondary markets and opportunistic access. In this paper we present the possibilities to apply reinforcement learning in WCDMA to enable the autonomous decision on spectrum repartition among cells and release of frequency bands for possible secondary usage. The proposed solution increases spectrum efficiency while ensuring maximum outage probability constraints in WCDMA uplink. We give two possible approaches to implement reinforcement learning in this problem area and compare their behavior. Simulations demonstrate the capability of two methods to successfully achieve desired goals.
Keywords
dynamic spectrum management, reinforcement learning, WCDMA.
Full Text
HyperLink Reinforcement Learning for Dynamic Spectrum Management in WCDMA
Page(s)
6-9

Performance Analysis of Routing Protocols in Ad-hoc and Sensor Networking Environments

F. Sarevski, V. Rakovic, O. Ognenoski, V. Atanasovski, and L. Gavrilovska
Topic:
Telecommunications Networks
Abstract
Ad-hoc and sensor networks are becoming an increasingly popular wireless networking concepts lately. This paper analyzes and compares prominent routing schemes in these networking environments. The knowledge obtained can serve users to better understand short range wireless network solutions thus leading to options for implementation in various scenarios. In addition, it should aid researchers develop protocol improvements reliable for the technologies of interest.
Keywords
Ad-hoc networks, Sensor networks, AODV, DSDV, Performance analysis.
Full Text
HyperLink Performance Analysis of Routing Protocols in Ad-hoc and Sensor Networking Environments
Page(s)
10-13

Automated Method for M-curve Signature Measurements of RR Devices and Modules

N. Pejovic, V. Orlic, M. Peric, M. Zecevic, and S. Marcetic
Topic:
Radio Communications
Abstract
In this paper we describe an automated method for testing the influence of selective fading on a radio-relay system and its vital modules in the form of M-curve signatures. Presented method is developed with a goal to make efficient measuremets of different RR devices generations, as well as to enable effective R&D of new RR equipment.
Keywords
Radio Communications
Full Text
HyperLink Automated Method for M-curve Signature Measurements of RR Devices and Modules
Page(s)
14-17

All-Optical Network with Simultaneous in-node Routing and Wavelength Assignment

N. S. Kojić, I. S. Reljin, and B. D. Reljin
Topic:
Optical Communications
Abstract
The paper describes a modified topology of an all-optical network with simultaneous in-node routing and wavelength assignment. The routing process is controlled by the Hopfield neural network. Intensive simulations demonstrate the stability and scalability of proposed algorithm and its capability for dynamic routing.
Keywords
NULLAll-optical networks, routing, wavelength conversion, optimization, Hopfield neural network.
Full Text
HyperLink All-Optical Network with Simultaneous in-node Routing and Wavelength Assignment
Page(s)
18-21

Perceived Speech Quality Estimation Using DTW Algorithm

I. Kraljevski, S. Chungurski, Z. Gacovski, and S. Arsenovski
Topic:
Multimedia
Abstract
In this paper a method for speech quality estimation is evaluated by simulating the transfer of speech over packet switched and mobile networks. The proposed system uses Dynamic Time Warping algorithm for test and received speech comparison. Several tests have been made on a test speech sample of a single speaker with simulated packet (frame) loss effects on the perceived speech. The achieved results have been compared with measured PESQ values on the used transmission channel and their correlation has been observed.
Keywords
Dynamic Time Warping, Mean Opinion Score, Perceptual Evaluation of Speech Quality.
Full Text
HyperLink Perceived Speech Quality Estimation Using DTW Algorithm
Page(s)
22-25

Search Result Clustering via Randomized Partitioning of Query-Induced Subgraphs

A. Bradic
Topic:
Software Tools and Applications
Abstract
In this paper, we present an approach to search result clustering, using partitioning of underlying link graph. We define the notion of "query-induced subgraph" and formulate the problem of search result clustering as a problem of efficient partitioning of a given subgraph into topic-related clusters. Also, we propose a novel algorithm for approximative partitioning of such a graph, which results in a cluster quality comparable to the one obtained by deterministic algorithms, while operating in a more efficient computation time, suitable for practical implementations. Finally, we present a practical clustering search engine developed as a part of this research and use it to get results about real-world performance of proposed concepts.
Keywords
Information Search and Retrieval, Graph Clustering, Randomized Algorithms, Web Measurement.
Full Text
HyperLink Search Result Clustering via Randomized Partitioning of Query-Induced Subgraphs
Page(s)
26-29

Universal Service for Socially Excluded Users

M. Petrovic, N. Gospic, D. Bogojevic, and B. Bakmaz
Topic:
Telecommunications Services
Abstract
This paper is about defining special measures within a universal service for potential socially excluded users, as a part of Project on US in Serbia. In the centre of research are people with disabilities, low income households, and welfare institutions in the Republic of Serbia. After analyzing regulations and statistical data, proposals for telecommunications services for these users are analyzed together with the costs of their realizations. At the end preliminary results of research are discussed.
Keywords
special measures, socially excluded users, universal service.
Full Text
HyperLink Universal Service for Socially Excluded Users
Page(s)
30-33

Gait Phases Recognition from Accelerations and Ground Reaction Forces: Application of Neural Networks

N. Mijailović, M. Gavrilović, and S. Rafajlović
Topic:
Signal Processing (Student Paper)
Abstract
The goal of this study was to test the applicability of accelerometer as the sensor for assessment of the walking. We present here the comparison of gait phases detected from the data recorded by force sensing resistors mounted in the shoe insoles, non-processed acceleration and processed acceleration perpendicular to the direction of the foot. The gait phases in all three cases were detected by means of a neural network. The output from the neural network was the gait phase, while the inputs were data from the sensors. The results show that the errors were in the ranges: 30 ms (2.7%) – force sensors; 150 ms (13.6%) – nonprocessed acceleration, and 120 ms (11%) – processed acceleration data. This result suggests that it is possible to use the accelerometer as the gait phase detector, however, with the knowledge that the gait phases are time shifted for about 100 ms with respect the neural network predicted times.
Keywords
accelerometers, force sensing resistor, gait phase, neural network.
Full Text
HyperLink Gait Phases Recognition from Accelerations and Ground Reaction Forces: Application of Neural Networks
Page(s)
34-37