Wi-Fi Hyunshik Seo

CONTENTS What is Wi-Fi ? A short history of Wi-Fi How Wi-Fi works – Internet access technology – Topology of Wi-Fi Location-aware applications based on Wi-Fi 2

What is Wi-Fi ?  The name Wi-Fi  Suggests Wireless Fidelity  A trademark of the Wi-Fi Alliance  used to describe the underlying technology of wireless local area networks (WLAN) based on the IEEE specifications  Initially, Wi-Fi was used in place of only the 2.4GHz b standard  Expanded the use of term to include a, b, g, and so on IEEE a: high speed extension to the 5GHz band IEEE b/g: high speed extension to the 2.4GHz band 3

What is Wi-Fi ?  Basics of Wi-Fi  Popular wireless networking technology  Enable devices such as computer or smartphone can connect to the internet  Works with radio waves through space  based on access point (AP) which broadcasts a wireless signal 4

A short history of Wi-Fi  1985 – Federal Communications Commission (FCC) opens up “garbage bands” for communication purposes without need for government licenses  1988 – Institute of Electrical and Electronics Engineers (IEEE) setup a committee called and defined Ethernet standard (later setup committee)  1999/2000 – b and a standards were ratified  Wireless Ethernet Compatibility Alliance (WECA) formed by Intersil, 3Com, Nokia, Aironet, and Lucent  1999 – Apple computers teamed with Lucent to add wireless slot to all laptops 5

How Wi-Fi works  Internet access technology  Connection between devices and internet  Wi-Fi devices needs to be within range of a wireless network or an internet hot spot where wireless access to the internet is available  Wireless internet access is available with access point which could be either wireless or wired device 6

How Wi-Fi works  Topology of a Wi-Fi  Point-to-point Usually very high speed and high capacity can be used to extend a net- work over great distances Requires a clear line of sight to tower 7

How Wi-Fi works  Point-to-multipoint  Similar technology to point-to-point network  more than one device communicates with a central point 8 Omnidirectional antenna

How Wi-Fi works  Multipoint-to-multipoint  Distributed gateway dev- ices  Self healing network  known as an ad-hoc or mesh network 9

Location-aware applications based on Wi-Fi (1)  Wi-Fi positioning system (WPS)  Based on wireless fidelity network  Uses information from APs around and from data- base through Wi-Fi to determine position 10

Location-aware applications based on Wi-Fi  Technologies in WPS  Getting wireless information from APs (such as MAC address, channel, signal strength, noise strength and so on)  Storing the APs’ locations in database, which are estimated from the obtained information from the APs  Gathering some information from mobile device  Making a determination of user’s position by comparing informat- ion from database and from mobile device 11

Location-aware applications based on Wi-Fi  Comparison with GPS  Relatively cheap  Availability in indoors  e.g. inside a building  High accuracy  GPS only determines the location of object within a few hun- dred meters but Wi-Fi can give a location within 20 to 30 me- ters  However, it depends on the density of Wi-Fi signals or the number of routers 12

Location-aware applications based on Wi-Fi  WiFi Location Services  Skyhook WiFi Location Service API (Launched in 2003)  Navizon WiFi Location Service API (Launched in 2005)  Verizon Wireless WiFi Location Service API (Launched in 2010)  Google WiFi Location Service API (Launched in 2008)  Apple iPhone WiFi Location Service API (Launched in 2010, Wi-Fi Finder) 13

Location-aware applications based on Wi-Fi  Wi-Fi Finder for iPhone –Indoor and outdoor route finding –Find Wi-Fi hotspots near you –Search for public Wi-Fi anywhere in the world 14

Location-aware applications based on Wi-Fi (2)  Wireless campus LBS  Project at the University of Twente (UT) in cooperation with companies  Based on technology and applications of wireless and mobile communication 15

Location-aware applications based on Wi-Fi  Features are  Mobile guide to find route both in and out of building  Mobile guide to find books in library  Mobile guide to find friends 16

Location-aware applications based on Wi-Fi (3)  The Cisco Location-Aware Healthcare system  To maintain many patients and staffs in hospital  based on Wi-Fi Location System  Features are  Monitoring of patient location  Optimizing workflow and staff management 17

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