WPAN & Bluetooth bluetooth

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					WPAN & Bluetooth

Wireless Technologies
WAN
(Wide Area Network)

MAN
(Metropolitan Area Network)

LAN
(Local Area Network)

PAN
(Personal Area Network)

PAN Standards Speed Range Applications
Bluetooth <1 Mbps Short Peer-to-Peer Device-to-Device

LAN
802.11a, 11b, 11g HiperLAN2 2–54+ Mbps Medium Enterprise Networks

MAN
802.11 MMDS, LMDS 22+ Mbps Medium–Long Fixed, Last Mile Access

WAN
GSM, GPRS, CDMA, 2.5–3G 10–384 Kbps Long PDAs, Mobile Phones, Cellular Access

Wireless Data Networks
50 Mbps
10 Mbps 2 Mbps 1 Mbps

802.11 is WiFi
Spread Spectrum Infrared Wireless Wireless LANs
LANs

Data Rates

WAP is small handhelds
2.5 GHz Service
Broadband PCS

56 Kbps

Circuit and Packet Data
19.6 Kbps 9.6 Kbps Narrow Band Wireless LANs Cellular, CDPD, Mobitex, DataTac

Narrowband PCS

Satellite
Wide

Local

Coverage Area

WPAN
 WPAN (Wireless Personal Area Network) •

• •

•

Is a computer network used for communication amongst computer devices (including telephones and personal digital assistants) close to one person. The reach of a PAN is typically a few meters. PANs can be used for communication among the personal devices themselves or for connecting to a higher level network and the Internet. A Wireless Personal Area Network (WPAN) can also be made possible with network technologies such as IrDA, Bluetooth and UWB

WPANs Technologies
 Infrared Wireless LAN
 Bluetooth
• Also an IEEE standard 802.15

Infrared Wireless LAN
– Require line of sight (LOS) to work (less flexible) – Main advantage: reduced wiring

usually mounted in fixed positions to ensure they will hit their targets
•New version: diffuse infrared, – Operates without a direct LOS by bouncing the infrared signal off of walls – Only able to operate within a single room and at distances of only about 50-75 feet

Bluetooth
 A Bluetooth WPAN is also called a piconet, and is

composed of up to 8 active devices in a masterslave relationship




The first Bluetooth device in the piconet is the master, and all other devices are slaves that communicate with the master A piconet typically has a range of 10 meters, although ranges of up to 100 meters can be reached under ideal circumstances

WPAN characteristics
 Short Range (at least 10m, up to 70m

possible)  Data rates (currently up to 55 Mb/s)  Short time to connect (<1s)  Peer to peer connectivity  Designed to support low power portable devices  Easy to use

WPAN Applications
 Personal home storage

 Printers & scanners
 Home theater

 Interactive video gaming  Exchanging information directly between

PDAs  Connecting a keyboard or mouse wirelessly to a desktop computer

Advantages and Disadvantages of WPAN


Advantages:
   

Dynamic network setup Usually quick and relatively simple to set up WPAN enabled devices are usually portable Needs less technical skills to deploy than LANs or WLANs. Typically have a limited range Currently limited to relatively slow data rates when compared with WLAN technologies Compatibility and interoperability issues (WPAN technologies are not usually compatible with each other. Some WPAN technologies such as Bluetooth are known to have had interoperability issues between devices from different manufacturers.) As small devices that are often associated with WPANs often have limited potential for adding extra hardware it is sometimes difficult to find suitable upgrade equipment. Devices with inbuilt WPAN technologies can be considerably more expensive than devices without WPAN technologies.



Disadvantages:
  





Ad Hoc Topology
 Peer-to-Peer (Ad Hoc)

Topology Can consist of 2 or more PCs with wireless network adapters. Sometimes called an Independent BSS (IBSS). Limited range.

Bluetooth – Ad hoc Network
 Consortium  Ericsson, Intel, IBM, Nokia, Toshiba - many members  Scenarios  connection of peripheral devices
• loudspeaker, joystick, headset
 

support of ad-hoc networking
• small devices, low-cost

bridging of networks
• e.g., GSM via mobile phone - Bluetooth – laptop

 It does not need any IP infrastructure

Bluetooth
Bluetooth wireless technology is a shortrange radio technology.  Bluetooth wireless technology makes it possible to transmit signals over short distances between telephones, computers and other devices and thereby simplify communication and synchronization between devices.  The Bluetooth wireless technology comprises hardware, software and interoperability requirements.  Transmits at up to 1 Mbps over a distance of 33 feet and is not impeded by physical barriers


Bluetooth – Blue Snarfing
Blue-snarfing, the technique leaves no trace of intrusion, steals the contents of a cellphone's address book , or even gain access to a user's laptop.  "Bluejacking" allows a user to send an anonymous and unauthorized message to another cell user. It has become primarily a means of entertainment for some individuals in crowded places - who'll send anonymous comments like "I like your tie" to people nearby.


Bluetooth was named after the 10th century Danish King Harold Bluetooth, who unified Scandinavia

Bluetooth (IEEE 802.15)
 A standard for Wireless Personal Area Network

(WPAN)


Provides networking in a very small area Includes small (1/3 of an inch square) and cheap devices designed to Provides a basic data rate of 1 Mbps
• Replace short distance cabling between devices – Keyboards, mouse, handsets, PDAs, etc • Up to 10 meters (current generation) • Up to 100 meters (next generation)



 

Uses Frequency Shift Keying (FSK) for data transmission (1 bit per symbol)

• Can be divided into several voice and data channels

Bluetooth Topology
 Uses the term “piconet” to refer to a

Bluetooth network


Consists of 8 devices
• A “master” device controlling other devices, “slaves” – Acts like an AP – Selects frequencies and controls access – All devices in a piconet share the same frequency range

 Uses Frequency Hopping Spread Spectrum (FHSS)  Available frequency range (2.4000-2.4835) divided into 79 separate 1-MHz channels  A data burst transmitted using one channel, next data burst uses the next channel, and so on.  Channels changed based on a sequence and established by the slave and the master prior to the data transfers
• 1,600 channel change per second


Bluetooth Media Access Control

Also used to minimize interference
• A noisy channel avoided eventually

 Not compatible with 802.11b  Potential interference problems (especially if many Bluetooth devices present close to .11b devices)


				
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posted:9/14/2009
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Lingjuan Ma Lingjuan Ma
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