<p>Internet Service Providers (ISP) har på senare år etablerat ett ökat antal Wi-Fi Hotspots på publika platser för att erbjuda Internettjänster så som e-post, Web och andra Internet-baserade program, till resande användare. Exempel på dessa platser är flygplatser, skolor, parker och städer. Växjö universitet har valt att bygga etttrådlöst nätverk på campus som man ska påbörja under sommaren 2005. Uppsatsen tar upp detta som fallstudie för diskussion av ämnet.</p> / <p>Lately Internet Service Providers (ISP) have established an increased amount of Wi-Fi Hotspots at public places to offer Internet based services like e-mail, web surfing etc to roaming users. Example of places like this are airports, schools, parks and cities. Växjö University has decided to implement a wireless network covering the university campus. This project is planned to start during summer of 2005. This project is the unicase for discussion in this bachelor thesis</p>

Topicality of the problem. Wireless WAN technologies which can provide multimedia services to customer in most cases are implemented by the commercial providers of voice services. Thus technologies are expensive in development of the Hot-Spots, where volatile expanded concentration of customers may be observed. For such purposes the main alternative technologies are the IEEE 802.11. In modern telecommunications industry the expansion of the IEEE 802.11 networks is one of the fastest growing segment of the telecommunications market. This technology has quickly found a significant place and popularity to provide the typical services of Internet in business, home networking, and etc. Growing evolution of Internet technologies determines transmitted data flows to take a shape of specific real time multimedia flows features. For such conditions the IEEE 802.11 general technology was not adapted. It is important to develop the new operation methods based on IEEE 802.11 without changing main standard specification. This method lets to adopt an existing in market equipment of IEEE 802.11 for multimedia or voice flows. The methodology of IEEE 802.11 technological expenditures influence estimation, presented in dissertation, has not been used before. This estimation method allows to evaluate rationality of physical resource utilization and to predict protocol modification directions. Also, method of synchronous voice communication in customer access is proposed. This solution allows... [to full text] / Mokslo problemos aktualumas. Plačiajuostės licencijuojamų dažnių bevielės technologijos, kurios paprastai skirtos vartotojams teikti komercines multimedijos ir balso paslaugas, yra per brangios vystant prieigos tinklus, kuriuose sutinkama didelė vartotojų koncentracija. Dėl to šios technologijos dažniausiai naudojamos tik komercinių balso paslaugų tiekėjų. Labiausiai tinkama alternatyva – yra IEEE 802.11 technologijos, kurių naudojimas modernių telekomunikacijų tinklų išplėtimui įvairiose tipinėse sąlygose yra pastebimai auganti telekomunikacijų rinkos dalis. Ši technologija greitai išplito ir tapo populiari verslo, namų, „paskutinės mylios“ ir kituose tinklų vystymo sprendimuose. Modernėjant Interneto technologijoms, telekomunikacijų tinkluose įsivyrauja multimedijos požymių turintys srautai, kurių sukurtoms specifinėms sąlygoms IEEE 802.11 technologijos nėra pritaikytos. Todėl svarbu kurti naujus, ribines galimybes išnaudojančius, bet specifikacijos nekeičiančius protokolus, kurie leistų rinkoje esančią įrangą adaptuoti realaus laiko srautams. Disertacijoje naudojama IEEE 802.11 MAC protokolo technologinių sąnaudų įtakos vertinimo metodika nebuvo taikoma. Šis vertinimo būdas leidžia įvertinti fizinio resurso užėmimo racionalumą ir numatyti IEEE 802.11 protokolo modifikavimo kryptis. Pateiktas sinchroninis vartotojų prieigos adaptacijos balso perdavimams būdas leidžia racionaliai panaudoti IEEE 802.11 protokolą balsui adaptuotose vartotojų prieigose. Todėl, galima teigti... [toliau žr. visą tekstą]

Mokslo problemos aktualumas. Plačiajuostės licencijuojamų dažnių bevielės technologijos, kurios paprastai skirtos vartotojams teikti komercines multimedijos ir balso paslaugas, yra per brangios vystant prieigos tinklus, kuriuose sutinkama didelė vartotojų koncentracija. Dėl to šios technologijos dažniausiai naudojamos tik komercinių balso paslaugų tiekėjų. Labiausiai tinkama alternatyva – yra IEEE 802.11 technologijos, kurių naudojimas modernių telekomunikacijų tinklų išplėtimui įvairiose tipinėse sąlygose yra pastebimai auganti telekomunikacijų rinkos dalis. Ši technologija greitai išplito ir tapo populiari verslo, namų, „paskutinės mylios“ ir kituose tinklų vystymo sprendimuose. Modernėjant Interneto technologijoms, telekomunikacijų tinkluose įsivyrauja multimedijos požymių turintys srautai, kurių sukurtoms specifinėms sąlygoms IEEE 802.11 technologijos nėra pritaikytos. Todėl svarbu kurti naujus, ribines galimybes išnaudojančius, bet specifikacijos nekeičiančius protokolus, kurie leistų rinkoje esančią įrangą adaptuoti realaus laiko srautams. Disertacijoje naudojama IEEE 802.11 MAC protokolo technologinių sąnaudų įtakos vertinimo metodika nebuvo taikoma. Šis vertinimo būdas leidžia įvertinti fizinio resurso užėmimo racionalumą ir numatyti IEEE 802.11 protokolo modifikavimo kryptis. Pateiktas sinchroninis vartotojų prieigos adaptacijos balso perdavimams būdas leidžia racionaliai panaudoti IEEE 802.11 protokolą balsui adaptuotose vartotojų prieigose. Todėl, galima teigti... [toliau žr. visą tekstą] / Topicality of the problem. Wireless WAN technologies which can provide multimedia services to customer in most cases are implemented by the commercial providers of voice services. Thus technologies are expensive in development of the Hot-Spots, where volatile expanded concentration of customers may be observed. For such purposes the main alternative technologies are the IEEE 802.11. In modern telecommunications industry the expansion of the IEEE 802.11 networks is one of the fastest growing segment of the telecommunications market. This technology has quickly found a significant place and popularity to provide the typical services of Internet in business, home networking, and etc. Growing evolution of Internet technologies determines transmitted data flows to take a shape of specific real time multimedia flows features. For such conditions the IEEE 802.11 general technology was not adapted. It is important to develop the new operation methods based on IEEE 802.11 without changing main standard specification. This method lets to adopt an existing in market equipment of IEEE 802.11 for multimedia or voice flows. The methodology of IEEE 802.11 technological expenditures influence estimation, presented in dissertation, has not been used before. This estimation method allows to evaluate rationality of physical resource utilization and to predict protocol modification directions. Also, method of synchronous voice communication in customer access is proposed. This solution allows... [to full text]

Submitted by Rafael Santana (rafael.silvasantana@ufpe.br) on 2017-08-30T17:07:46Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Antonio_Thesis.pdf: 3530353 bytes, checksum: 0ba09bccbe8eb163cd5b4646977ba882 (MD5) / Made available in DSpace on 2017-08-30T17:07:46Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Antonio_Thesis.pdf: 3530353 bytes, checksum: 0ba09bccbe8eb163cd5b4646977ba882 (MD5) Previous issue date: 2016-02-12 / Atualmente as redes locais sem fio (WLANs) em ambientes internos estão presentes na maioria dos prédios públicos. Estas redes, além da sua função principal, podem ser utilizadas para localização de pessoas e objetos, salientando que nestes ambientes não é adequada a utilização do sinal de GPS para esta finalidade. Diversos estudos e pesquisas nesta área têm sido realizados. Serviços baseados na localização interna possuem inúmeras aplicações nas áreas de segurança, médica, monitoramento, navegação, auxílio a deficientes, gerenciamento de pessoas, entre outras e hoje já movimentam um mercado de US$1 Bilhão. Com a proliferação da Internet das Coisas (IoT), estes valores serão ainda maiores. Os sistemas de localização interna utilizam tecnologias como Ultrassom, Infravermelho, RFID, Bluetooth e WLAN, variando conforme a precisão, exatidão, custo, velocidade de resposta, infraestrutura e aplicação. O presente trabalho propõe uma técnica de localização interna que utiliza a intensidade do sinal recebido (RSS — Received Signal Strength) das redes WLAN presentes como medida para localização. Na técnica proposta, é feito inicialmente um mapeamento das intensidades dos sinais da WLANs existentes. Estes valores são classificados através de um Algoritmo de Agrupamento (clustering) e, posteriormente, são aplicados, a cada agrupamento, algoritmos de regressão para o cálculo da localização. Associada a estas técnicas são aplicados filtros visando minimizar as variações do sinal medido decorrentes de interferências do meio. Esta técnica não necessita de grandes esforços de calibração nem alterações na estrutura existente, apenas utilizando a rede WLAN já instalada, obtendo assim uma precisão compatível com aplicações de localização de pessoas e objetos e auxílio em navegação em ambientes internos. Na implementação e testes da técnica proposta, foi empregado o processador Edison da Intel para a coleta das intensidades dos sinais — RSS e como plataforma de servidor foi utilizada a estrutura de nuvem da Microsoft através do Azure-Studio Machine Learning, apropriada para a análise e predição de dados da técnica utilizada. As medições para composição dos conjuntos de testes e validação foram realizadas no prédio do Centro de Informática da UFPE, demonstrando que apesar do baixo esforço de calibração, sem alteração da estrutura existente, atendem aos requisitos necessários. Resultados preliminares mostram que 60% das amostras estavam com erro inferior a 5 metros. / Currently, wireless local networks (WLANs) in internal environments are present in most of the public buildings. These networks, in addition to their main function, can be used to locate people and objects, stressing that in these environments it is not adequate the use of the GPS signal to this goal. Several studies and researches in this area have been made. Services based in internal location have many applications in security, health, monitoring, navigation, disabled assistance, and people management, among other areas. Nowadays, they already move a US$ 1 billion market. With the proliferation of the Internet of Things (IoT), these values will increase even further. Internal location systems use technologies such as Ultrasound, Infra-red, RFID, Bluetooth, and WLAN, varying according to the required precision, accuracy, cost, response speed, infrastructure, and application. The following work proposes an internal location technique that uses the received signal strength (RSS) from existing WLAN networks as a location measurement. In the proposed technique, is initially made a mapping of the existing WLANs signals intensities, these values are classified through a Clustering Algorithm and, after that, regression algorithms are applied to each group towards a location classification. Associated to these techniques, filters are applied aiming to minimize the measured signal variations due to the environment interferences. This technique doesn’t require big calibration efforts, nor changes in the existing structure, just uses the already installed WLAN network, obtaining a precision compatible to the one required for people and objects location and assistence in internal environments navigation. In the proposed technique’s implementation and tests, it was used Intel’s Edison processor to collect RSS signal’s intensities. As a server platform, it was used Microsoft’s cloud structure through the Azure-Studio Machine Learning, appropriate for the used technique’s analysis and data prediction. The main set of tests and validation was accomplished in the UFPE Informatics Center building, showing that despite low calibration effort, without changing the existing structure, it complies with the necessary requirements. Preliminary results show that 60% of the samples had errors under 5 meters.

Die Standorte der SLUB verfügen seit März 2005 an allen Arbeitsplätzen im Öffentlichkeitsbereich über WLAN (Wireless Local Area Network). Dieses Angebot wurde von den Benutzern mit großem Interesse aufgenommen, bereits wenige Monate nach der Einführung waren allein in der Zentralbibliothek bis zu 1.000 WLAN-Nutzer je Tag keine Seltenheit.

Aufbau einer LBS Infrastruktur im WLAN

Today a growing number of people need to work on laptops with wireless Internet connection. There are two common wireless Internet access solutions: wireless local area network (WLAN) via hotspot, and high speed wide area cellular network via mobile broadband device such as 3G/4G Universal Serial Bus (USB) dongle. USB dongle was the pioneer product in 3G/4G market, and it is still a popular device in many countries. Mobile broadband can offer both high speed access and mobility. Technically mobile broadband allows Internet connection as long as your mobile transceiver can access your cellular network operator’s network. However, in practice the data rates experienced by a user via mobile broadband are not comparable to the data rates that are available via WLAN. Moreover, mobile broadband has been implemented according to multiple different standards. Hence, in order to provide a user with locally optimal service requires that user must make use of heterogeneous networks. Furthermore, the variety of networks gets increasing due to the emergence of various 4G networks. The aim of this thesis is to explore how heterogeneous networks could be exploited to provide a user of a laptop computer with locally optimal service, while hiding the complexity of this heterogeneous service. The research focuses on the implications of integrating multiple network interfaces into a single USB dongle. Our research shows that multi-mode USB dongle is still needed in market, though there are competitions from smartphones and mobile WiFi devices. We point out that the PPP (Point to Point Protocol) based USB dongle should update to Ethernet USB protocols such as RNDIS (Remote Network Driver Interface Specification) or USB CDC (Communications Device Class) protocols. Furthermore, we suggest a USB dongle should be able to work as a WLAN access point to share Internet with other mobile devices, and it should also work as a WLAN client which can join other hotspots. If hotspot operators can authenticate USB dongles by SIM cards, then users can easily access a great number of hotspots belong to these operators. / Mer än någonsin behöver människan arbeta med bärbara datorer med anslutning till trådlöst Internet. Det finns två vanliga trådlösa Internet-anslutningar: trådlöst lokalt nätverk (WLAN på engelska) via en hotspot, eller höghastighets mobilnät via mobilt bredband som 3G/4G Universal Serial Bus (USB) dongel. USB dongeln var pionjär produkten inom 3G/4G marknaden, och den är fortfarande en populär enhet i många länder. Mobilt bredband kan erbjuda både tillgång till höga hastighet och bra mobilitet. Mobilt bredband tillåter, rent tekniskt, användaren hålla en Internet-anslutning så länge mobilen har tillgång till mobilnätets operatörsnät. Men i praktiken är datahastigheterna, som användaren upplever ha via det mobila bredbandet, inte jämförbar med de datahastigheter som är tillgängliga via WLAN. Dessutom har mobilt bredband implementerats enligt flera olika standarder. Således, för att förutse en användare med en optimal lokal tjänst, krävs det att användaren måste använda heterogena nätverk. Dessutom blir olika nätverk allt större på grund av uppkomsten av olika 4G-nät. Syftet med denna avhandling är att undersöka hur heterogena nätverk skulle kunna utnyttjas för att förutse en laptop användare med optimal lokal nätverksservice, samtidigt dölja komplexiteten för användaren om den heterogena tjänsten. Forskningen fokuserar på konsekvenserna av att integrera flera nätverksgränssnitt till en enda USB-dongel. Vår forskning visar att det fortfarande behövs en multi-mode USB dongel på marknaden, dock existerar det konkurrens från smartphones och mobila WiFi-enheter. Vi påpekar även i avhandlingen att PPP (Point-to-Point Protocol) baserade USB dongeln bör uppdateras till Ethernet USB-protokoll, såsom RNDIS (Remote Network Driver Interface Specification) eller USB CDC (Communications Device Class) protokoll. Vidare föreslår vi att en USB-dongel bör kunna fungera som en kopplingspunkt för att dela Internet med andra mobila enheter, och att den också bör fungera som en WLAN-klient som kan ansluta sig till andra hotspots. Om hotspot operatörer kan autentisera USB-donglar genom SIM-kort, så kan användarna enkelt få tillgång till ett stort antal hotspots som tillhör dessa operatörer.

IEEE 802.11 based Wireless Local Area Networks (WLANs) in addition to being used as access networks for providing traditional data services, are now also being used as access networks for providing realtime services such as VoIP and multimedia streaming. These realtime services are sensitive to latency, hence requiring seamless or low delay service from the lower layers throughout an ongoing session. The IEEE 802.11 standard does not define any technique or algorithm to provide seamless connectivity during the process of handoff, hence it does not require 802.11 based WLANs to provide the same. Thus, it is typical that there is a latency of 500 milliseconds to 1000 milliseconds during the handoff, before the mobile station can connect and receive data from the new access point (AP). However, many realtime services can not tolerate this much latency. The problem of handoff latency is further aggravated when WLANs are secured using IEEE 802.11i standard and when Authentication, Authorization &amp; Accounting (AAA) services are involved in controlling network access to 802.11 based WLANs. This thesis will address the entire handoff process and examine the latency -- especially regarding AAA services. Different techniques and suggestions will be presented and analyzed closely at different layers and based on the results, an appropriate/efficient algorithm is suggested which will reduce this handoff latency, such that that seamless handoff can be achieved and realtime services can be provided over 802.11i enabled IEEE 802.11 WLANs. / Wireless Local Area Network (WLAN), baserat på IEEE 802.11 har traditionellt nyttjats som som accessnät för vanliga datatjänster. Ett allt vanligare användningsområde har blivit att nyttja samma nät för realtidstjänster som Voice over IP (VoIP) och mutimedia. Realtidstjänster är känsliga för fördröjningar. Fördröjningar som bland annat kan erhållas från de lägre nivåerna i OSI-stacken. IEEE 802.11-standarden definierar ingen teknik eller algoritm för att säkerställa avbrottsfri/fördröjningsfri transmission av data vid handoff och följdaktligen så kan man idag inte luta sig mot denna standard för att erhålla denna funktionalitet. Med nyttjande av befintlig IEEE 802.11 standarder erhålls fördröjningar på mellan 0,5 till 1 sekunder. Detta är naturligtvis inte acceptablet för många realtid och realtidsliknande tjänster. Problemet vid handoff accentueras ytterliggare om kravs ställs på AAA-tjänster för att säkerställa säkerheten i ett IEEE 802.11-baserat WLAN. Denna uppsats adresserar hela handoffprocessen med tillhörande fördröjningar – speciellt med hänsyn till AAA-tjänsterna. Olika tekninker och förslag presenteras och analyseras på olika nivåer. Baserat på erhållna resultat föreslås en algoritm för att reducera tidsåtgång vid handoff, så att realtidsliknande tjänster erhålls, utan störande fördröjningar, vid nyttjande av 802.11i.

[pt] Enquanto o uso das WLAN cresce em ritmo acelerado, inúmeros problemas relacionados à tecnologia de segurança, definida no IEEE 802.11b, têm sido abordados em publicações técnicas, apontando deficiências e vulnerabilidades, através dos quais indivíduos não autorizados podem ter acesso às informações disponibilizadas pela rede. A precariedade na autenticação, confidencialidade e integridade dos dados dos mecanismos internos do Padrão IEEE 802.11b exige a operação conjunta com o Padrão IEEE 802.1x. Esta combinação possibilita a autenticação e criptografia dos dados de forma mais eficiente e confiável. No entanto, é possível que haja sobrecarga de pacotes, devido à inserção de tráfego extra para autenticação dos usuários e criptografia das mensagens, podendo ocasionar comprometimento na performance da rede. Desta forma, avaliou-se qual a efetiva degradação no desempenho das redes IEEE 802.11b, devido à implementação dos mecanismos de segurança, sejam eles intrínsecos ao Padrão ou combinados com o Padrão IEEE 802.1x, utilizando os protocolos FTP (File Transfer Protocol) e HTTP (Hipertext Transfer Protocol). / [en] Meanwhile the use of WLAN grows in accelerate pass, a large number of problems related to the security issues in the IEEE 802.11b have been discussed in technical papers, pointing vulnerabilities and deficiencies, from where a non authorized access to the informations passing on the network could be possible. The lack of strong solutions in authentication, confidentiality, and integrity of the data in the internal mechanisms of the protocol IEEE 802.11b, demands to operate in conjunction with the protocol IEEE 802.1x. Therefore it is possible to get authentication and cryptography in a efficient and trustful manner. The amount of extra packets, inserted for authentication and cryptography of the messages, could have a negative impact in the performance of the network. A experimental measurements of the degradation of the network throughput, when the mechanisms of IEEE 802.1x are used, were done and presented here.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Wireless local area networks (WLANs) enable the extension of the Internet to aircrafts in flight. To establish this wireless network segment, commercial-of-the-shelve (COTS) 802.11b wireless Ethernet bridges were used. Wireless Ethernet bridges were chosen over optical wireless technology and Internet protocol (IP) satellite modems mainly because of their lower costs, ease and flexibility of implementation. Additionally, 802.11b wireless networks allow a wide range of mobile data devices such as laptop computers and personal digital assistance high-speed wireless access to critical information and applications resided on the aircrafts networks. Since 802.11b WLAN media is shared and traffic generated by other users will degrade the overall performance of the network. With the continual wide spread use of 802.11b WLAN, an aircraft in flight will experience network congestions and poor performance across all the frequency channels. The congestion and poor performance issues can be minimized by tracking the airborne wireless LAN using highly directional antenna and RF filtering. The method of tracking multiple 802.11 wirelesses LAN and the RF subsystem will be described. The applications of 802.11b wireless networks to man and unmanned aircrafts flight research will be discussed.