Low Rate Wireless Personal Area Networks

Low Rate Wireless Personal Area Networks

Wireless Communications

Low Rate Wireless Personal Area

Networks

• Describe a wireless personal area network (WPAN)

• List the different WPAN standards and their

applications

• Explain how IrDA, Bluetooth, and ZigBee work

• Describe the security features of low-rate WPAN

technology

What is a WPAN?

• Wireless personal area network (WPAN)

– Group of technologies that are designed for

short-range communications

– Eliminates the need for wires or cables to interconnect multiple devices

• Applications for WPAN technology include:

– Synchronizing PDAs, cellular, and Smartphones

– Home control systems (smarthome)

– Cordless telephones

What is a WPAN? (continued)

• Applications for WPAN technology include

(continued):

– Industrial control systems

– Location — smart tags used to locate people at home

or at the office

– Security systems

– Interactive toys

– Inventory tracking

• Advantages

– WPAN devices use very little power

– Short range helps maintain security and privacy

Infrared WPANs (IrDA)

• Most common infrared connection today

– Based on the IrDA specifications

• IrDA specifications

– Define both physical devices and network protocols

• IrDA devices’ characteristics

– Provide walk-up connectivity

– Provide a point-to-point method of data transfer

• Between only two devices at a time

Infrared WPANs (IrDA) (continued)

Infrared WPANs (IrDA) (continued)

• Serial Infrared (Version 1.0)

– Designed to work like the standard serial port on a PC – Uses a UART (Universal Asynchronous

Receiver/Transmitter)

• Microchip that also controls a computer’s serial interface

• Fast Infrared (FIR) (Version 1.1)

– Extends the data rate to 4 Mbps

– When two IrDA devices first communicate

• They both transmit using SIR

• Then they shift to FIR speed

RF WPANs

• Offer functionality beyond that of IR devices

• Include

– Bluetooth

– 802.15.4 (ZigBee)

IEEE 802.15.1 and Bluetooth

• Industry specification

– Bluetooth Special Interest Group (SIG)

• Defines small-form-factor, low-cost wireless radio

communications

• IEEE licensed this wireless technology

– To adapt and copy a portion of the specification as the base material for 802.15.1

• 802.15.1 standard

– Approved in March 2, 2002

– Fully compatible with Bluetooth version 1.1

Bluetooth Protocol Stack

• Bluetooth RF layer

– Defines how the basic hardware that controls the radio transmissions functions

– Data bits (0 and 1) are converted into radio signals and transmitted

• Radio module

– A single radio transmitter/receiver (transceiver)

– Only hardware required for Bluetooth to function

– Bluetooth can transmit at a speed of up to 1 Mbps

Bluetooth Protocol Stack (continued)

Bluetooth Protocol Stack (continued)

Bluetooth Protocol Stack (continued)

Bluetooth Protocol Stack (continued)

• Network topologies (continued)

– Scatternet

• Group of piconets in which connections exist between different piconets

– To communicate in each different piconet

• Device must use the master device address and clock

of that specific piconet

– Bluetooth device can be a slave in several piconets

• But can be a master in only one piconet

– A master and slave can switch roles in a piconet

Bluetooth Link Manager Layer

(continued)

• Link between Bluetooth devices (continued)

– Bluetooth power usage (continued)

• Power-saving modes

– Active – Sniff – Hold – Park

Low Rate WPAN Security

• Security should be of little concern with WPANs

• One of the most serious concerns is social engineering

• Designing security in WPANs

– Much more difficult task than in other networking

technologies

• Public key infrastructure (PKI)

– Unique security code, or key, provided by a certificate authority

• Certificate authority

– Private company that verifies the authenticity of users

Security in Infrared WPANs

• Limited to the line-of-sight characteristic of this type of

connection

• IrDA specification makes no provision for encrypting data or protecting the connection

– Users may encrypt a file before exchanging it

• IrDA devices support open access

– So that anyone can transmit files without first notifying the

device’s owner

• Open access can be a major security concern

• Bluetooth provides security at the LMP layer

– Using authentication

• Authentication is based on identifying the device itself

• Authentication scheme is a challenge-response strategy

• Encryption is the process of encoding communications

• The most common infrared connection today is

based on the IrDA standard

– IrDA devices cannot send and receive at the same time

– IrDA is easy to use

• Bluetooth is a wireless technology that uses short-range radio frequency (RF) transmissions

– Supported by over 2,500 hardware and software

vendors