WLAN : the promises of the radio access

Abstract:  This paper presents some results of a study concerning the radio propagation at 60 GHz in residential environments performed by the IETR (Electronic and Telecommunication Institute of Rennes, France). This study is part of a RNRT1 project named "COMMINDOR"2. This exploratory project concerns the very high data rate (155 Mbit/s) and small range (about 10 m) radio communication systems for future home networks, which will permit multimedia equipment interconnection and control. The study is based on several measurement campaigns realized with a channel sounder based on the sliding correlation technique. This channel sounder has a 500 MHz bandwidth and a 2.3 ns effective time resolution. The measurements have been performed in residential furnished environments. The study of the angles-of-arrival (AOA) emphases the importance of openings (such as doors, staircase, etc.) for the radio propagation between adjacent rooms. A particular attention is paid to the influence of human activity on radio propagation. It is shown that people movements can make the propagation channel unavailable during about one second. From the characterization study of the indoor radio propagation, several recommendations concerning the deployment of the very high data rate 60 GHz wireless networks are derived.

Key words: Indoor radiocommunication, Electromagnetic wave propagation, Millimetric wave, Wireless LAN, Domotic, Residential facility, High rate, Radio channel, Characterization, Frequency time representation, Measurement method, measurement result.

Multimedia Forward Error Correcting codes for wireless LAN

Benoît PARREIN*, Nicolas NORMAND*, Jeanpierre GUÉDON*

* Laboratoire IRCCyN, Équipe Image & Vidéo Communications, CNRS UMR 6597, École polytechnique de l'Université de Nantes, La Chantrerie Rue Christian Pauc, BP 50609, F-44306 Nantes cedex3 France

Abstract:  In this paper the forward error correction (FEC) codes useful for multimedia wireless transmissions are discussed. The class of usable codes are produced by multiple description (packet equivalence during transmission) after an initial hierarchical representation stage (joint source channel coding). The Mojette transform is used to perform the implementation. A fair comparison with other optimal codes (systematic or not) is provided. JPEG2000 images transmission under a wireless link shows possible strategies.

Key words: Wireless LAN, Error correcting code, Multimedia service, Redundancy, Mathematical transformation, Picture quality.

Ultra Wideband: the radio link of the future?

Manuel PEZZIN*, Julien KEIGNART*, Norbert DANIELE*, Sébastien de RIVAZ*, Benoît DENIS*, Dominique MORCHE*, Philippe ROUZET**, Régis CATENOZ**, Nils RINALDI**

* CEA-LETI - (Direction de la recherche technologique), 17,rue des Martyrs, F-38054 Grenoble, France

** ST Microelectronics - (Advanced System Technology), 39, chemin du Champ des Filles, CH - 1228 Plan les Ouates, Genève, Switzerland.

Abstract:  A new data transmission technique is about to create a revolution in the field of wireless local area networks. This new method, called Ultra Wideband, is based on the transmission of data through the communication channel below the noise floor. It involves transmitting very short duration pulses, which has the effect of spreading the signal energy across a wide frequency range. The objective of this article is to report on the state of the art in this research area, and to outline the main advantages of this promising data transmission method.

Key words: Radiocommunication, Wide band, Ultrashort pulse, State of the art, Date communication, Pulse position modulation, Radio channel, Pulse shape, Gauss signal, Demodulation.

An Information Service System using Bluetooth in an exhibition hall

Yohei TAKADA*, Masayuki KISHIMOTO*, Nobuyuki KAWAMURA*, Norihisa KOMODA*, Hiroaki OISO*, Takahiro YAMASAKI**, Tadao MASANARI***

* Dept. of Multimedia Eng., Graduate School of Information Science and Technology, Osaka University 2-1, Yamadaoka, Suita, Osaka 565-0871 Japan

** Dept. of Electrical Eng., Faculty of Eng., Osaka Sangyo University 3-1-1 Nakagaito Daitou-shi, Osaka 574-8530 Japan

*** Canon i-tech Inc.

Abstract:  In an exhibition hall, it is important to provide visitors with information about the exhibit. In this paper, an information service system using Bluetooth in an exhibition hall is proposed. This system automatically provides an explanation of the nearby exhibit to visitors based on the estimated location information. This system can also act as a guide through the exhibit, leading the recommended tour. Moreover, several management support functions using the visitors' location log are proposed. To keep continuous connection between access points and a visitor's mobile device for smooth browsing operation, a pre-download method and a special handover are proposed. The pre-download method decides the information to be downloaded based on the visitor browse. The download order is determined based on the prediction of the visitor movement. Through the simulation in various room-layouts, access point layouts and walking routes, the effectiveness of the proposed methods are shown. The prototype of the information service system that installs the proposed methods has been developed.

Key words: Wireless LAN, Information dissemination, Exhibition, Portable terminal, Museum, Hypermedia navigation, Object location, Radiocommunication handover, Downloading.

Location Discovery in Enterprise-based Wireless Networks: Case Studies and Applications

Simon G. M. KOO*, Catherine ROSENBERG*, Hoi-Ho CHAN*, Yat Chung LEE*

* School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907-1285, USA. Email: {koo,cath,hchan,lee85}@ecn.purdue.edu

Abstract:  We have designed and implemented a Web service for location discovery (LODS) and a location-based printing service that uses LODS on a network with wireless LAN connectivity based on IEEE 802.11 that is typical to campuses and enterprises. The need for location management and location-based services is linked to the mobility of the users. While location discovery is already implemented in cellular telecommunication networks since the system needs to know where are the users to connect them to incoming calls, the need for such a service was not so crucial in data network where in general the mobile user is the client and initiates the connections. We propose several solutions to implement our location discovery service depending on the underlying networking architecture and compare these solutions in terms of several criteria. LODS allows mobile users to find their approximate location within the campus or the enterprise and allows location-based applications to find out the location of a user to suggest the nearest points of interest, e.g., printers, elevators, and vending machines. We also present the case of our location-based remote printing service that was deployed in Purdue wireless network.

Key words: Wireless LAN, Object location, Value added service, Case study, Telecommunication application.

Business opportunities through UMTS-WLAN networks

Dimitris VAROUTAS¹, Dimitris KATSIANIS¹, Thomas SPHICOPOULOS¹, François LOIZILLON², Kjell Ove KALHAGEN³, Kjell STORDAHL⁴, Ilari WELLING^5, Jarmo HARNO⁵

1. University of Athens, Dpt of Informatics & Telecommunications, Panepistimiopolis, Ilisia, Athens, GR-157 84, Greece.

2. France Télécom R&D, DMR/SPP, 38, rue du Général Leclerc 92794 Issy-les-Moulineaux cedex 9, France.

3. Telenor Research & Development, Telenor, N-1331 Fornebu, Norway.

4. Telenor Networks, Telenor, N-1331 Fornebu, Norway

5. Nokia Research Center, P.O. Box 407, Fin-00045 Nokia Group, Helsinki, Finland.

Abstract:  This article outlines the economic feasibility of mobile operators that combine nationwide mobility with 3G networks and hot spot coverage with WLANs. WLANs are based on HIPERLAN/2 architecture and the UMTS network exploits WCDMA/FDD technology. The evaluated business scenarios are focused on two different deployment areas, in terms of demographic characteristics and mobile penetration: a large and a small European country. The business case spans 2002 to 2011 with UMTS' roll-out year in 2002 and WLAN's in 2004, covering indoor hot-spot areas (stations, airports, stadiums, etc.) where demand is high. The demand for this UMTS-WLAN roaming case is evaluated based on observations from Europe's current mobile market and its evolution. Usage scenarios of different service packages corresponding to both residential and business markets have been taken into account. Direct investments and operational costs as well as revenue streams from traffic have been calculated. The methodology and the tool developed in ACTS-TERA [1] and IST-TONIC [2] projects have been utilized for this case study. Economic conclusions have been derived, presented and discussed using key profitability factors. Profitability for all scenarios and business pro- files has been calculated, presented and discussed. It includes a sensitivity analysis in order to identify the major opportunities and threats, for specific service sets as well as critical parameters and uncertainties. A wide audience from mobile operators and service providers to retail companies interested in entering the 3G market, can exploit this information.

Key words: Wireless LAN, Mobile radiocommunication, UMTS, Network interworking, Economic aspect, Telecommunication operator, Telecommunication regulation, Demand forecasting, Economic forecasting.

Challenges for Wi-Fi, business models and spectrum issues

Michel BERNE*, Gérard POGOREL**

*GET/INT - 9, rue Charles Fourier 91011 Evry cedex France

**GET/Télécom Paris - 46, rue Barrault 75634 Paris cedex 13 France

Abstract:  Amongst the various versions of WLAN, Wi-Fi is widely used and raises two interesting issues from an economic, strategic and regulatory perspective. One deals with the perspectives of the two business models appeared so far : a cooperative, non-commercial one, for local use and a commercial one involving Wireless ISPs and broadband access aggregators for roaming. Both show robust growth today but present weaknesses. The other issue deals with spectrum allocation as Wi-Fi uses an unlicensed frequency band. Its development challenges traditional spectrum management, putting forward "open spectrum" management models. But while in the US Wi-Fi has been able to develop without any significant regulation hurdles, the situation is more complicated in Europe and especially in France where regulation authorities have more recently addressed the issue.

Key words: Wireless LAN, Economical aspect, Radio frequency management, Economical model.

A constraint programming approach to assign cells to switches in personnal communication networks

Grâce AMOUSSOU*, Matthieu ANDRÉ*, Gilles PESANT*, Samuel PIERRE*

* Département de génie informatique, École Polytechnique de Montréal, C.P. 6079, succ. Centre-ville, Montréal, Québec, Canada H3C 3A7

Abstract:  This paper discusses the problem of assigning cells to switches in mobile networks. It can be summed up as finding an optimal assignment of cells to switches in order to minimize a cost function composed of the cost of handoff between cells and the cost of cabling between cells and switches. We propose here an algorithm based on constraint programming for this problem. The choice of this method is motivated by its active use of constraints in the search for solutions, which in turn leads to the reduction of the search space and the diffi- culty of the problem. We introduce a new Constraint Optimization Problem model for assigning cells to switches, a definition of a lower bound on the cost of each cell and a development of search strategies, leading to an efficient way of finding the best solutions. Results showed that our algorithm leads to an optimum solution for medium size networks and can find good solutions for large size networks.

Key words: Mobile radiocommunication, Cellular network, Mathematical programming constrained optimization, Allocation, Radiocommunication handover, Telephone switching system, Dynamic programming, Algorithm.

A countermeasure against DDoS attacks using Active Networks technologies

Dai KASHIWA*,**, Eric Y. CHEN*,***, Hitoshi FUJI*

* NTT Information Sharing Platform Laboratories, 1-1, Hikarinooka, Yokosuka-shi, Kanagawa, 239-0847, Japan

** Faculty of Science and Technology, Keio University.

*** The University of Tokyo

{kashiwa,eric,fuji}@isl.ntt.co.jp.

Abstract:  A Distributed Denial of Service (DDoS) attack consumes the resources of a remote host or network by sending a massive amount of IP packets from many distributed hosts. It is a pressing problem on the Internet as demonstrated by recent attacks on major e-commerce servers and ISPs. Since the attack is distributed and the attack tools evolve at a rapid and alarming rate, an effective solution must be formulated using a distributed and adaptive approach. In this paper, we propose a countermeasure against DDoS attacks using a method we call Active Shaping. Our method employs the Active Networks technologies, which incorporates programmability into network nodes. The Active Networks technology enables us to deter congestion and bandwidth consumption of the backbone network caused by DDoS attacks, and to prevent our system from dropping packets of legitimate users mistakenly. This paper introduces the concept of our method, system design and evaluates the effectiveness of our method using a prototype..

Key words: Computer security, Internet, Congestion control, Active telecommunication network, Distributed system, Adaptive method, Automatic classification.

A multi-level generic model for content image retrieval abstract

Rachid OULAD HAJ THAMI*, Hind CHAARANI*, Mohamed DAOUDI**, Mustapha RACHIK***

* Laboratoire d'Informatique, Équipe IHM, ENSIAS, Université Mohamed V Souissi, B.P 713, Rabat, Agdal, Maroc

**Équipe MIIRE, ENIC, Télécom Lille 1/INT, Rue G. Marconi, Cité Scientifique, 59000 Villeneuve d'Ascq, France

***Département de mathématiques, Faculté des Sciences Ben M'Sik Sidi Ottman, Casa, Maroc.

Abstract

In this paper we propose a generic model for content image modelling. The model is based on several levels of information. Each level is called view and relates to a class of information. We distinguish three types of views : the concept, relation and interpretation views. The view concept or relation makes it possible to define respectively the concepts or the calculable relations automatically that do not require any particular interpretation. The view interpretation relates to the interpretation of the contents of the image. The number, the nature and the contents of each view are adaptable and can vary according to the type of application. The operational model is based on the nested conceptual graphs which we extended. The model is implemented and operational and the results obtained are very encouraging.

 

Key words : Image analysis, Image description, Modeling, Hierarchical model, Graph, Database query, Information retrieval.

 

 

 

 

BER improvement of an asynchronous ds-cdma system using chaotic spreading sequences

Stéphane PENAUD*, Philippe BOUYSSE*, Jacques GUITTARD*, Raymond QUÉRÉ*, Alban DUVERDIER**

* IRCOM UMR CNRS 6615 , I.U.T GEII / Université de Limoges, 7, Rue Jules Vallès 19100 BRIVE, France.

** CNES Toulouse 18, Av. Edouard Belin 31401 TOULOUSE Cedex, France.

 

Abstract:  The use of chaotic sequences as spectral spreading sequences in a Direct Sequence-Code Division Multiple Access is proposed in this paper. The simulation of the system is performed with the system simulator Omnisys. The chaotic spreading sequences are generated from a non-linear recursive equation. The Bit Error Rate of this system is compared with the BER of the same system using binary Gold sequences. The results show that chaotic sequences can improve performances in terms of allowable number of users.

 

Key words: Code diffusion multiple access, Direct sequence spread spectrum, Error rate, Chaos, Multilevel signal, Non linear equation, Numerical simulation, Nonsynchronous transmission.

 

 

Differential Rain Attenuation Statistics on two Converging Point-to-Point Terrestrial Links Located in a Tropical Climatic Region

Athanasios D. PANAGOPOULOS*, John D. KANELLOPOULOS*

* Division of Electroscience - Department of Electrical and Computer Engineering, National Technical University of Athens, 9 Iroon, Polytechniou Street, Zografou, GR-15773, Athens, Greece.

 

Abstract:  An analytical procedure for the prediction of differential rain attenuation statistics on two converging point-to-point terrestrial links located in a tropical climatic region is presented. It is based on an appropriate convective raincell model and the fundamental assumption that the point rainfall rate statistics follows a gamma form. A tropical raindrop size distribution is also adopted. Numerical results are compared with a set of available experimental data over pairs of converging terrestrial links in Brazil.

 

Key words: Electromagnetic wave propagation, Radio wave, Radio relay link, Attenuation, Rain, Statistical study, Zone tropicale.

 

 

 

 

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