Aquesta tesi presenta l'aplicació d'una nova metodologia de prototipatge ràpid basada en plataformes per a subsistemes de comunicació, en concret, la part digital de la capa física del protocol sense fils HiperLAN/2.Les principals contribucions d'aquest treball de recerca són:- Formulació i validació d'una metodologia de disseny que transforma directament les especificacions a nivell de sistema a plataformes físiques, mantenint de forma intensiva la verificació heterogènia multinivell.- Exploració i implementació de noves arquitectures hardware per millorar algorismes complexos en la cadena HiperLAN/2, obtenint models sintetitzables per la capa física digital de l'emissor i receptor de l'HiperLAN/2.- Prototipatge de la part digital de la capa física de l'emissor HiperLAN/2 amb una tassa de transmissió de dades de 12MBits/s, en una plataforma adequada per a sistemes WLAN. El propòsit d'aquest prototipatge és demostrar l'alta productivitat de la metodologia que acaba implementant el disseny en plataformes físiques.Aquest treball s'estructura en quatre parts: conceptes fonamentals, metodologia de prototipatge ràpid, disseny de la capa física i prototipatge de l'emissor.Als conceptes fonamentals, es fa una introducció a la modulació OFDM explicant el model de senyal, propietats i avantatges d'aquesta modulació. A continuació, es presenta l'estàndard sense fils HiperLAN/2 que utilitza la modulació OFDM. En concret, es presenten els entorns de treball, la topologia, la capa física, la complexitat del model i tipus de ràfegues de l'estàndard HiperLAN/2. A la metodologia de prototipatge ràpid d'un sistema WLAN, es presenta la metodologia utilitzada pel prototipatge de l'emissor i receptor de la part digital de la capa física de l'HiperLAN/2. A continuació es fa una introducció al prototipatge ràpid, s'exposen els requeriments de les plataformes de prototipatge d'un sistema WLAN, es mostren l'estat de l'art d'entorns i plataformes per a sistemes WLAN i s'expliquen les arquitectures de les FPGAs de Virtex. A continuació, es presenta la metodologia WLAN amb els mètodes de sincronització i els fluxos de disseny que utilitza. En concret, es presenten dos fluxos de disseny diferents, un flux clàssic i l'altre més específic adaptats als sistemes WLAN, els quals ofereixen varies alternatives molt interessants de verificació heterogènia multinivell. Per acabar, es comenten els conceptes d'abstracció funcional, d'ortogonalitat i d'heterogeneïtat de la metodologia. Al disseny de la capa física de l'emissor i receptor es mostren en detall les seves estructures i els seus components computacionals. S'han proposat contribucions significatives pels mòduls de la IFFT/FFT, equalitzador de canal, sincronitzador, interleaver/deinterleaver i Viterbi. Els resultats de síntesis mostren la millora en comparació amb dissenys alternatius actuals. Els models obtinguts de l'emissor i del receptor mostren la seva funcionalitat i les seves prestacions a nivell de sistema. Al prototipatge de l'emissor, es descriuen el canvis aplicats al model de l'emissor per tal de fer el prototipatge en una plataforma específica. Al final, es presenten els resultats obtinguts a través de l'analitzador d'espectres i es fa una estimació del consum de potència de l'emissor que validen el mètode proposat. / This thesis presents the application of a new platform-based rapid prototyping methodology to the design of a communications subsystem, specifically the digital part of the physical layer of the HiperLAN/2 wireless protocol.The main contributions of this research work are: - Formulation and validation of a design methodology that directly transforms system level specifications to silicon platforms, while stressing heterogeneous multilevel verification.- Exploration and implementation of new hardware architectures to improve some complex algorithms in the HiperLAN/2 chain, obtaining synthesizable models for the digital part of the physical layer of HiperLAN/2 transmitter and receiver, which were validated in the hardware architecture. - Prototyping of the digital part of the physical layer of the HiperLAN/2 transmitter with a 12Mbits/s data transmission rate in a silicon platform, well-suited for WLAN systems. The aim of this prototype is to show the high productivity of the design methodology that ends into real platforms. This dissertation is structured in four parts: fundamental concepts, rapid prototyping methodology, design of the physical layer, and transmitter prototyping. The fundamental concepts part introduce OFDM modulation, and outlines the signal model as well as its advantages and disadvantages. Next, the standard wireless HiperLAN/2, that uses OFDM modulation, is presented. The working environment, network topology, physical layer, model complexity and burst types are discussed.The chapter on rapid prototyping methodology for a WLAN system describes the design methodology proposed to prototype the transmitter and receiver of the digital part of the physical layer of HiperLAN/2, starting from the WLAN system requirements that lead to the selection of specific prototyping platforms. Current HW implementation capabilities are presented through the architecture of Virtex FPGAs, used as core hardware device. Next, we detail the WLAN system design methodology with the design flow and synchronization methods used. Two design flows are presented, a more general flow and a specific one, adapted to WLAN systems. These design flows detail different powerful options of heterogeneous multilevel verification, that profit from modern concepts of functional abstraction, orthogonality and heterogeneity. The part about physical layer design of transmitter and receiver shows their structures and detail their computational components. Significant contributions have been proposed for IFFT/FFT, channel equalizer, synchronization, interleaver/deinterleaver and Viterbi modules. Synthesis results show their performance quality compared to current alternative designs. The overall results obtained from the transmitter and receiver models show also its global behavior and system level performance. Transmitter prototyping describes changes applied to the transmitter model in order to map it into the specific silicon platform. Out of this complete prototype we extracted data from the spectrum analyzer and of transmitter's power consumption that validate the proposed approach.

This paper is a study and comparison between the two Wireless LAN (WLAN) standards HiperLAN/2 and IEEE 802.11a. WLANs are used instead or together with ordinary LANs to increase mobility in for example an office. HiperLAN/2 is an European standard developed by ETSI and the IEEEs standard is American. A WLAN-card consists roughly of a Medium Access Control (MAC), Physichal layer (PHY) and an antenna. The antenna is the same for the different standards. Both standards operates at 5.4 GHz with a maximum transmission rate at 54 Mbit/s and they use OFDM to modulate the signal. This means that the physical layer in the two standards is similar. The differences between the standards are in the Medium Access Control (MAC) layer. HiperLAN/2 has a much more complex MAC since it is developed with the starting point in cellular phones. Therefore this MAC is not very similar to ETHERNET that is the protocol used by regular network. On the other hand it is built to be compatible with cellular phones and other applications. The 802.11a MAC is very much the same as in the 802.11b standard that is the most used standard at present. The difference is that 802.11a can send at much higher data rates. This MAC is build with starting point in ETHERNET so it has a similar interface to the computer. This makes it less complex. The different MACs can provide different services. The greatest difference is that 802.11a can use a distributed send mode where any STA can send if the medium is idle. This reminds a lot of ETHERNET but they use different methods to sense if the medium is idle. In HiperLAN/2 are all transmissions scheduled by the AP. 802.11a can operate in a similar way but at the moment this mode is not as fully developed as in HiperLAN/2. There are working groups in IEEE that works toward an improvement of 802.11a so it can use queues with different priorities, this is already implemented in HiperLAN/2. Another important issue in wireless environment is security. Both standards use encryption to protect their messages. The difference is that HiperLAN/2 changes their encryption key for every connection where 802.11a uses the same key the whole time. This gives HiperLAN/2 a better security with todays standard but thereare working groups dealing with implementing key-exchange functions and Kerberos use in 802.11a. Chapter 8 is a description of a program that we developed in C++. The program is used to monitor the different registers and ports a WLAN-card use. It is written for a 802.11b card and should be used together with Windows 2000. The source code can be found in appendix C.

<p>This paper is a study and comparison between the two Wireless LAN (WLAN) standards HiperLAN/2 and IEEE 802.11a. WLANs are used instead or together with ordinary LANs to increase mobility in for example an office. HiperLAN/2 is an European standard developed by ETSI and the IEEEs standard is American. </p><p>A WLAN-card consists roughly of a Medium Access Control (MAC), Physichal layer (PHY) and an antenna. The antenna is the same for the different standards. </p><p>Both standards operates at 5.4 GHz with a maximum transmission rate at 54 Mbit/s and they use OFDM to modulate the signal. This means that the physical layer in the two standards is similar. </p><p>The differences between the standards are in the Medium Access Control (MAC) layer. HiperLAN/2 has a much more complex MAC since it is developed with the starting point in cellular phones. Therefore this MAC is not very similar to ETHERNET that is the protocol used by regular network. On the other hand it is built to be compatible with cellular phones and other applications. </p><p>The 802.11a MAC is very much the same as in the 802.11b standard that is the most used standard at present. The difference is that 802.11a can send at much higher data rates. This MAC is build with starting point in ETHERNET so it has a similar interface to the computer. This makes it less complex. </p><p>The different MACs can provide different services. The greatest difference is that 802.11a can use a distributed send mode where any STA can send if the medium is idle. This reminds a lot of ETHERNET but they use different methods to sense if the medium is idle. In HiperLAN/2 are all transmissions scheduled by the AP. 802.11a can operate in a similar way but at the moment this mode is not as fully developed as in HiperLAN/2. There are working groups in IEEE that works toward an improvement of 802.11a so it can use queues with different priorities, this is already implemented in HiperLAN/2. </p><p>Another important issue in wireless environment is security. Both standards use encryption to protect their messages. The difference is that HiperLAN/2 changes their encryption key for every connection where 802.11a uses the same key the whole time. This gives HiperLAN/2 a better security with todays standard but thereare working groups dealing with implementing key-exchange functions and Kerberos use in 802.11a. Chapter 8 is a description of a program that we developed in C++. The program is used to monitor the different registers and ports a WLAN-card use. It is written for a 802.11b card and should be used together with Windows 2000. The source code can be found in appendix C.</p>

Les télécommunications sans fil mobiles connaissent un intérêt croissant depuis plus d'une décennie. Elles se décomposent en deux types d'applications : la téléphonie et les réseaux informatiques. La complémentarité de ces deux technologies offre un potentiel énorme pour fournir aux usagers une mobilité sans interruption de service quand l'utilisateur passe du domaine public au domaine privé et réciproquement. <br /><br />Toutefois, quel que soit le système de communication sans fil envisagé, il est soumis à une contrainte forte associée au caractère multitrajets du canal de propagation. Celles-ci se traduisent par des évanouissements parfois profonds et rapides du niveau de réception et par la sélectivité en fréquence du canal. Ainsi, le phénomène de trajets multiples associé au canal radioélectrique engendre des perturbations lors de la transmission de signaux à un instant, une position et une fréquence donnée.<br /><br />L'objectif de cette thèse s'inscrit dans ce contexte puisqu'il porte sur la caractérisation spatio-temporelle du canal de propagation tenant compte d'une ou plusieurs antennes à l'émission comme à la réception.<br /><br />Ainsi, dans ce document sont définis les outils théoriques permettant le calcul des fonctions caractéristiques. Ce formalisme est alors intégré dans un logiciel de caractérisation spatio-temporelle, pouvant considérer en entrée des données issues de campagnes de mesures ou provenant de modèles de propagation. Enfin, il propose une ouverture vers l'utilisation des informations de caractérisation du canal dans un système HiperLAN/2.