Nikola Rozic

Software defined radio based implementation of RFID tag in next generation mobiles

Radio Frequency identification (RFID) technology has become important tool for items identification and tracking. In those purposes different types of RFID technologies could be used, depending on its application. Limitations of passive RFID technology, related to tags reading range and confidence in harsh environments, puts restrictions on implementation in the real life scenarios. To overcome the issue, but staying within the standards, we have considered development and implementation of active backscattering tag technology, which significantly improves tag reading range and confidence. Software Defined Radio (SDR) technology is promising technology for building mobiles of multiple radio standards in 4G networks. Regarding stated RFID technologies limitations and SDR technology, we present development and implementation of the Software Defined Radio (SDR) active backscattering tag compatible with the EPCglobal UHF Class 1 Generation 2 (Gen2) RFID standard. Such technology can be used for wide spectra of applications and services. The system is developed and tested on SDR platform. Validity and performances of developed Gen2 SDR tag are shown through actual presented results.

Speech recognition over Bluetooth ACL and SCO links: a comparison

Bluetooth is an emerging technology for short-range wireless communication. It is designed to transfer data over asynchronous connectionless (ACL) links and voice over synchronous connection-oriented (SCO) links. SCO packets are sent at regular intervals and are never retransmitted, while ACL packets are retransmitted in case of error. In this paper we have investigated speech recognition performance for voice transferred over ACL and SCO links at various channel qualities. Our experiments have shown that channel quality has severe impact on speech recognition performance for voice earned over SCO. This justifies the use of ACL links for voice transmissions in speech recognition applications.

Early Frame Break Policy for ALOHA-Based RFID Systems

Throughput of dynamic frame slotted ALOHA (DFSA) in radio frequency identification (RFID) systems depends on the tags quantity estimate. This paper shows how to apply the slot-by-slot (SbS) estimate approach, along with the policy for the early frame-break. Simulation results show noticeable throughput improvements.

Linearized Combinatorial Model for optimal frame selection in Gen2 RFID system

Radio Frequency Identification (RFID) technology become an important tool for items identification and tracking. In this paper we observe RFID Gen2 communication protocol between the RFID reader and the low-cost battery free passive RFID tags. To establish communication between the reader and tags, Gen2 uses Dynamic Frame Slotted ALOHA (DFSA) Medium Access Control (MAC) layer protocol with Q-Selection algorithm for frame size adaptation. DFSA constraints of Gen2 RFID reader-tag communication may become an issue in the fast identification of all tags in the interrogation area. To identify all tags as soon as possible, DFSA frame size should be selected properly so its throughput is maximized, and that can be achieved only if one can estimate number of interrogated tags correctly. In this paper we present Linearized Combinatorial Model (LCM) algorithm for the optimal frame size adaptation. Developed scheme is implemented and tested on Universal Radio Serial Peripheral 1 (USRP1) Gen2 reader application. Results analysis shows that our scheme outperforms Q-Selection algorithm.

Academic networking in alps-adria countries

he featured topic of the 8th IEEE Conference 011 Software, Telecommunications and Computcr Networks (SoftCOM 2000), which was held aboard the ship Marko Polo cruising along the Adriatic coast on the route Split (Croatia) Rijeka (Croatia) Trieste (Italy) Venice (Italy) from October 10-13,2000, was Academic Networking in AlpsAdria Countries. The conference was sponsored by the University of Split, Croatian Telecom, Telecom Center Split, and IEEE Communications Society. Besides the conference itself a number of accompanying events took place aboard the ship, including the Business Forum and Exhibition, which was organized on the car deck. The special session was divided into two parts and held on October 13 aboard the ship Marko Polo, which was anchored in Venice, Italy. The first part of the session was chaired by professor Algirdas Pakstas from the University of North London, United Kingdom and the second part by Professor Ignac Lovrek from the Faculty of Electrical Engineering and Computing of the University of Zagreb, Croatia. The featured topic attracted authors and participants from government institutions dealing with academic networking as service/infrastructure providers, and teachers from universities and researchers from institutes as users. A total of 12 papers were presented by authors from Italy, Hungary, Germany, Slovenia, Switzerland, and Croatia: *Advanced Solutions for Distance Learning via Satellite, by M. de Blasi, University of Lecce, Italy; C. des Dorides, Alenia Spazio, Italy. *Trends in Networked Collaborative Virtual Environments, by S. Pandzic, C. Joslin, N. Magnenat Thalmann, University of Geneva, Switzerland. *Homer 11: Man-Machine Interface to Internet for Blind and Visually Impaired People, by N. Pavesic, J. Gros, S. Dobrisek, F. Mihelic, University of Ljubljana, Slovenia. *Academic and Research Network of Slovenia, by A. Jauk, M. Bonac, ARNES, Slovenia; I. Ozimek, G. Kandus, Jozef Stefan Institute, Slovenia. .The LAN of TUB and its Links with other Universities in Budapest, by G. Nemeth, G. Remzso, L. Szandi, G. Varga, University of Budapest, Hungary Collaboration between Academia and Industry: Telecommunications and Informatics at the University of Zagreb, by I. Lovrek, M. Kos, B. Mikac, University of Zagreb, Croatia. *The Role and Strategy of an ARNet in a Developing Country, by Z. Bekic, J. Gojsic, P. Pale, CARNet, Croatia *The Implementation of Broadband Network Technologies in CARNet, by N. Bartolincic, I. Pezelj, I .Velimirovic, A. Zigman, CARNet, Croatia. *CARNet: Educated Users for Effective Utilization of IT, by M. Milinovic, J . Tingle, V. Vrga, CARNet, Croatia. *The Italian Academic Network GARR: Evolution in the Gigabit Era, by Claudio Allocchio, Claudia Battista, Massimo Carboni, Luca dell’Agnello, GARR Italian Academic and Research Network, Italy. *DFN Gigabit Network The Backbone for Teleteachingmelelearning in Higher Education: Status Report, by Ralf Paffrath, DFN, Germany. The presented papers cover main topics of academic networking including national strategies and network architectures, the role of academic networks in education and collaboration with industry, technological aspects, particularly applications of broadband and satellite systems, and user aspects including services for impaired persons. The Italian academic network Gruppo Armonizzazione Reti di Ricerca (GARR) was presented including various aspects, particularly its evolution, described through GARR-B and GARR-G phases. The GARR-B phase deals with increasing access bandwidth, introduction of new services like a computational GRID, a large dedicated mesh of VPNs for a user group, and increasing connectivity in southern and Mediterranean regions. GARR-G phase represent a GARR gigabit pilot project with SDH and WDM transmission systems in a multicarrier and multi-operator reality. The idea of expanding GEANT service to Italy and possibly beyond Italy toward the Mediterranean area is explored through the GARR-G phase. The Academic and Research Network of Slovenia (ARNES) is described as part of the TEN-155 EU project for high-speed pan-European interconnection between national research networks. ARNES participates in a number of international projects dealing with advanced networking. It is a full national member of the Trans-European Research and Educational Networking Association (TERENA). ARNES joined TF-Cashe activities and was one of the proposers of the socalled 1.5-level cache hierarchy concept. Croatian Academic and Research Network (CARNet) was presented in a wider way than only as an Internet provider for the academic community. As it has stated, an Academic and Research Network (ARNet) should not only provide communication and information infrastructure for the academic community, but also be a research testbed and even a pilot for other nationwide networks, thus taking the role of organizer and motivator for the community. To accomplish this, ARNet’s strategy should be to ensure connectivity and provide content through reference information, referral information, common databases, centralized databases, and information services. The development of CARNet was slight(Continued on page 4)

Source modeling of MPEG video

A new source model of variable bit rate (VBR) video conforming to the MPEG (Moving Picture Expert Group) standard is presented. An extensive statistical analysis of a 2-hour long MPEG empirical trace is performed, including both classical descriptive statistics and a somewhat newer method related to self-similarity phenomena. The observed statistical properties of the analyzed trace are explained by considering the MPEG coding mechanisms and physical nature of video data. The proposed model is based on the statistical decomposition procedure. Each of the components are modeled by an ARIMA process. The effect of scene changes, causing a large frame spikes, is also incorporated into the model.

Distribution of the noise squared norm in OFDM systems interfered by class a impulsive noise

Recently there is a noticeable interest in investigation of the squared norm distribution of complex-valued Gaussian variables that have different variances. A typical example is consideration of the channel state information (CSI) in multi-antenna systems. A similar problem appears in communication systems interfered by Middleton Class A impulsive noise. In this paper we develop exact expressions for the squared norm distribution in the time and frequency domains in OFDM systems interfered by Class A impulsive noise. Accurate approximation by the chi-square distribution based on equating the first two moments has been also derived.

Development of the communication/information infrastructure at the academic institution

The quality and functionality of the communication/information infrastructure is essential for the development of the academic institution. The status of the academic institution and its relationship with other subjects such as government institutions and companies establish the basic potentials and constraints for the infrastructural development. The Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture (FESB) of the University of Split in Croatia is an example of the academic institution with dynamic development of its communication/information infrastructure. The support by the Ministry of Science and Technology and the CARNet has been the major driving force in development of the basic communication/information infrastructure. The major result of this cooperation has been the deployment of the local area network and provision of the Internet connections and services. However, the intensive collaboration with the renown ICT companies on joint research and development projects in the area of ICT technology and services have generated new potentials for development of the communication/information infrastructure at FESB. Important results of this cooperation include installation of the digital PABX, development of the experimental communication network based on technologies such as ATM, ISDN, IP, xDSL, GSM and DECT. Another important step is the ongoing process of introduction of the wireless local area network to enable the mobility of students and faculty members within the premises. The plans for the future development of the communication/information infrastructure at FESB include continuous work on introduction of new ICT technologies and improvement of the functionality through the cooperation with the partners.

Local thresholding classified vector quantization with memory reduction

A new memory reduction method for classified vector quantization (CVQ) is presented. Symmetry reflection, rotation and inversion of edge subimages are used to join appropriate edge classes thus reducing the memory requirements for edge codebooks by 8(4) times for the classifier used in this paper. Besides the memory reduction, our method generates the more robust codebooks thus increasing the PSNR for images outside the training set. It also relieves codebook generation for high bit rate by reducing the number of images that should be inside the training set. The proposed method has been tested with a classifier that is based on the comparison of locally thresholded image vectors with a predefined set of binary edge templates.

Analytical and simulation analysis of the explicit-rate ABR flow control algorithms: transient behavior

An analytical formulation of the transient behavior of the available bit rate (ABR) explicit-rate traffic flow control for the single-node case is presented. Precisely, the transient effects due to available capacity increasing (a ramp-up) of the previously proposed distributed explicit-rate allocation (DERA) scheme, and generally valid available capacity decreasing (a ramp-down) transient case are analytically formulated, using fluid-flow traffic approximation. An analytical formulation of the queue build-up, and characteristic time instants provides an insight of the cause and effect relationships, and can be used for buffer dimensioning. In addition, quantification of the queue build-up and the dependence on other system parameters may prove useful in evaluating other algorithms and designing those that avoid it. The obtained analytical results are verified through discrete-event simulation.