Thursday, May 3, 2012

Day 6 - Wednesday, 2 May 2012

Hi everyone. The topic for this week lesson is regarding to WIRELESS TECHNOLOGY. Wireless is also known as Unbounded or Unguided Media.

Wireless networking technologies range from global voice and data networks, which allows users to establish wireless connections across long distances, to infrared light and radio frequency technologies that are optimized for short-range wireless connections.

Wireless connection

Wireless signals are used to send signal through the air between devices instead of using a physical cable.

Wireless network most commonly used to refer to a telecommunications network whose interconnections between nodes is implemented without the use of wires, such as a computer network.

Wireless telecommunication networks are generally implemented with some type of information transmission system that uses electromagnetic waves.

Wireless communication involves:
1. Radio frequency communication
2. Microwave communication
3. Infrared (IR) short-range communication 


- require line-of-sight transmission and reception
two types of antennas:
parabolic dish and horn
- works like a funnel (catching a wide range of waves and directing to a common point called focus).


- looks like gigantic scoop.
- outgoing transmission are broadcast up a stem and deflected outward in series.
- broadcast up and deflected outward in a series of a narrow parallel beams by the scooped shape of the beam.


- same principle as terrestrial microwave.
- single bounce.
- satellite acting as a super tall antenna and repeater.
- capability= any location on earth no matter how remote.
- high quality(very clear) communication without requiring a huge investment.
- same speed as the earth.
- geosynchronous satellite = orbit speed is based on distance from planet.
- up link = transmission from earth to satellite
- down link = transmission from satellite to earth
- minimum 3 satellites to provide full global transmission.


- the underlying technology of wireless local area network (WLAN).
- based on the IEEE 802.11 specifications.
- used for mobile computing devices, such as laptops, in LANs, increasingly used for more services, including internet and VoIP phone access, gaming and basic connectivity of consumer electronics.
- frequency 2.4 GHz
- range 100-300 feet (indoor) 300-900 feet(outdoor)


3G networks are in between standard. 3G is seen more as pre4G instead of a standard of its own. The advantage of 3G networks have over 2G networks speed. 3G networks are built to handle the needs of today's wireless users. This standard of wireless networks increase the speed of internet browsing, picture and video messaging, and handheld GPS use.


4G (Beyond 3G) is like the other generations in that its advantages lies in promised increased speed in data transmission. There is  currently no formal definition for 4G, but there are objectives. One of these objectives is for 4G to become a fully IP-based system, much like modern computer network. The supposed speeds for 4G will be between 100 Mbit/s and 1 Gbit/s.


One of the most interesting things about a cell phone is that it is really a radio. An extremely sophisticates radio, but a radio nonetheless. A good way to understand the sophistication of a cell phone is to compare it to a CB radio or a walkie-talkie. A CB radio is a simplex device. That is, two people communicating on a CB radio use the same frequency, so only one person can talk at a time. A cell phone is a duplex device, so it uses one frequency for talking and a second, separate frequency for listening. A CB radio has 40 channels. A cell phone can communicate on 1,664 channels. Cell phones also operate within cells and they can switch cells as they move around. Cells gives cell phones incredible range. Someone using a cell phone, on the other hand, can drive clear across a city and maintain a conversation the entire time. Cells are what give a cell phone its incredible range.


A radio wave is an electromagnetic wave propagated by an antenna. Radio waves have different frequencies and by turning a radio receiver to a specific frequency you can pick up a specific signal. 


- An industrial specification for wireless personal area networks (PANs).
- Designed for very short range <10m.
- Connect and exchange information between devices such as mobile phones, laptops, PCs, printers, digital cameras and video game consoles over a secure, globally unlicensed short-range radio frequency. 
- Frequency 2.4 GHz.

- Data speed up to 3Mbps.

That is all from me for this week.
Thank you for reading my entry.

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