Chapter 3

Help you understand different types of wireless communication methods including:◦ Bluetooth◦ Radio

It will help you understand their advantages and disadvantages and typical applications.

There are many way of communicating between devices.

Some methods make use of wireless technology to transmit data from one source to another source.

Bluetooth is a protocol which allows wireless transmissions to take place.

It works by transmitting data over the 2.5Ghz radio frequency (between TV and satellite frequencies!)

There are 3 confirmed versions:◦ Version 1.2 – 1Mbps◦ Version 2.0 – 2Mbps◦ Version 3.0 – 21 Mbps

You can see the difference in speed here:◦ http://www.youtube.com/watch?v=Eha7RcHs_TE

It works at a range of about 10 metres (like infrared).

The big difference between Bluetooth and infrared is that Bluetooth does not require line of sight whereas infrared does.

You can find Bluetooth on lots of different kinds of technology including:◦ Mobile phones◦ Laptops◦ Headsets◦ Console controllers

Typical Bluetooth applications include:

◦ Bluetooth headsets used to allow for hands free communication to take place using a mobile phone or games console.

◦ Transferring files between two mobile phones.

◦ Connecting a mobile phone to a PC so that it can act as a modem for the laptop

Pros Cons

Widely accepted standard and can be found on many mobile devices such as mobile phones and laptops.

Transfer speeds are slower than other wireless devices.

Does not require line of sight in order to work.

Maximum range of about 10 metres.

Does have security measures in place to prevent non-authorised access to devices.

You can connect only 2 devices together at any one time. For example, if you are using a Bluetooth hands free headset and want to send your friend a picture using Bluetooth, you would have to disconnect your headset before connecting to your friend’s mobile phone.

Transmitting data using radio frequencies has been around for ages...

But over the years we have got better and better at transmitting data and the types of data.

Wi-Fi networks make use of the IEEE 802.11 standard.

Standard Bit Rate (Mbit/s) Indoor Range Outdoor Range

802.11a 54 15 metres 30 metres

802.11b 11 45 metres 90 metres

802.11g 54 45 metres 90 metres

802.11n 600 70 metres 250 metres

Note: Other standards are in the pipeline. For more information visit:http://en.wikipedia.org/wiki/IEEE_802.11 (scroll down to standard and amendments)

Typical applications of Wi-Fi technology include:

◦ Wireless-enabled laptops being able to connect to an organisations network.

◦ Laptops and smart-phones connecting to ‘hotspots’ to access the internet.

◦ Wireless devices connecting to home networks.

◦ Connecting devices such as scanners and printers to the home network wirelessly.

◦ Connecting games consoles to the internet.

Pros Cons

No need for cables to connect devices to one another.

Transfer rates are slower than hard-wired connections.

Allows for devices to be portable. Range is restricted indoors – and the range can vary depending on the density and materials of the walls.

Line of sight is not required. Lots of wireless devices connected to the network can reduce bandwidth speeds.

Users can save money by using one device at home and at work rather than having two separate devices.

Security is an issue as wireless communications can be intercepted. This means encryption is really important but this also results in slower data transfer speeds as more data needs to be sent!

Transfer rates are ok for most uses.

Because the standard is set in stone...it means any wireless device can connect to a wireless network.

Method Advantage Disadvantage Where is it used?

Bluetooth

Radio

Describe two applications of Bluetooth.

Discuss the advantages and disadvantages of Bluetooth.

Describe three applications of wireless communication.

Why are standards necessary for wireless networks?

Why is encryption necessary on a wireless network?