Sunday, 13 May 2012

Wireless Technology

Hi, everyone. This is week 12 already... Yeah, we can go back soon..
In today's lesson, I have learned on Wireless Technology such as Bluetooth and Broadband.

What is Bluetooth?

-Bluetooth is an industrial specification for wireless Personal Area Network (PANs).

- Bluetooth allows people to transfer or exchange information between devices such as laptops, cellular phone, printers, digital camera over a secure, globally unlicensed short range radio frequency.

- Bluetooth is acceptable for two or more devices that are 10 metres to each other and does not require high bandwidth.

- Bluetooth device advertise all the services they provide, these make the utility of devices much more accessible and more convenient without worrying about network addresses, permissions and all other considerations that go with typical networks.

- IEEE develop standard 802.15.

- utilises a radio - based means it does not require line of sight to communicate.

 - Before communication can happen,  a device must ask whether the other device is accept or reject.

- The sending device = client and the receiving device = server

- All Bluetooth devices can operate as both client or server.

- Concept: focused on point-to-point and point-to-multiple connection with small network called piconet.


- Each piconets hold up 8 active units.

- When multiple network exist within the same room = a scatternet

- 3 types of data links between any 2 nodes:

·         An asynchronous data channel

·         Simultaneous voice channels

·         Asynchronous data channels

- In order to resist interference Bluetooth employs spread spectrum frequency = hopping


-  To avoid interference with other system, Bluetooth sending weak signal of 1 milliwatt.

- Therefore, the low power limits the range of Bluetooth device to about 10 metres.

- Although it is low power, the walls in a house would not stop the signal.

What are the Pros and Cons of using Bluetooth?


- Wireless

- Communication increase.

- Support half and full duplex of communication.

- Low power consumption (no batteries used)

- Spread spectrum frequency hopping


- High cost of manufacturers such as the components.

- Too technologically advanced.

- Ease to use.

What is the future of Bluetooth?

- 1 MB/sec, 10 metres, 7 active devices.

- can be used wherever you desire

- cheap, various electrical appliances drive the price down

- Maybe high speed network solution.

What is Broadband?

 -Is a technology aimed at providing high speed wireless access over a wide area from devices such as personal computers to data networks.

- According to 802.16-2004 standard, broadband means having 'instantaneous bandwidth greater than 1 MHz and supporting data rates greater than 1.5 Mbit/s.

- It is estimated to have a range of 50km (30 miles)

What is Infrared?

Infrared wireless will use infrared radiation to convey data.

- Infrared wireless uses short and medium range communication and control.

- Some system use line of sight mode (straight line without obstruction) and some use diffuse mode (not the straight line) to transmit data from transmitter to the receiver.

-  Unlike radio-frequency wireless link, Infrared cannot pass through walls but Infrared wireless is more private than radio-frequency wireless.

That is all for me. Thank you. :)