Saturday, 2 June 2012

Wireless Technology

Wireless telecommunications is the transfer of information between two or more points that are not physically connected. Distances can be short, such as a few metres for television remote control, or as far as thousands or even millions of kilometres for deep-space radio communications. It encompasses various types of fixed, mobile, and portable two-way radios, cellular telephones, personal digital assistants (PDAs), and wireless networking. Other examples of wireless technology include GPS units, Garage door openers or garage doors, wireless computer mice, keyboards and Headset (audio), headphones, radio receivers, satellite television, broadcast television and cordless telephones.

Wireless communication involves:

• radio frequency communication
• microwave communication, for example long‐range line of sight via highly directional antennas or short line‐of‐antennas, shortrange communication
• infrared (IR) short‐range communication, for example from remote controls or via IRDA Applications may involve point‐to‐point communication, point‐to‐multipoint communication, broadcasting , cellular networks and other wireless networks.

Devices commonly use wireless networking
  • portable computers, desktop computers computers, hand‐held computers,
  •  personal digital assistants (PDAs), 
  • cellular phones, 
  • pen‐based computers, 
  • pagers, GPS etc

The network is literally classified into four. They are:
1.      PAN (personal area network) – covers the network of personal devices such as printer and mobile devices.
2.      LAN (local area network) – covers relatively small geographical area such as home, school and also office.
3.      WAN (wide area network) – covers large geographical area and consist of two or more LAN connected together using communication technology. Internet is the largest WAN.
4.      MAN (metropolitan area network) – network designed to service the large area such as cities. Consist of multiple LAN and the size is between LAN and WAN.

Type of Wireless Network as stated above:

  • Wireless wide area networks (WWANs) 
  • Wireless metropolitan area networks (WMANs) 
  • Wireless local area networks (WLANs) 
  • Wireless personal area networks (WPANs)

Application : Data Networking.
  • Infra Red 
  • wireless local area networks (WLANs)
  • broadband wireless.
  • Bluetooth,
  • WiMax
- Infrared Data Transmission
• IrDA (Infrared Data Association) is an industry standard for wireless communication with infrared light. (Non RF)
• Many laptops sold today are equipped with an IrDAcompatible transceiver that enables communication with other devices, such as printers, modems, LANs, or other laptops. The transfer speed ranges from 2400 bps to 4Mbps.
• Requires line of sight transmission

- Bluetooth: is an industrial specification for wireless
personal area networks (PANs).
  • Designed for very short range 
  • <10 m 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
- Wi‐Fi the underlying technology of wireless local area
networks (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 such as televisions and DVD players, or digital cameras 
  • Frequency 2.4 GHz
  • Range 100‐300 feet(indoor) 300‐900 feet(outdoor
- WiMax :To extend the range of wireless network
  • Speed upt to 70Mbps
  • Range 30 miles
  • Provides access to internet access to fixed location with larger coverage
- Broadband wireless access
  • 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 the 802.16‐2004 standard, broadband means 'having instantaneous bandwidth greater than around 1 MHz and supporting data rates greater than about 1.5 Mbit/s'.
  • It is planned to be used in the next few years and is estimated to have a range of 50km (30 miles).

Cellular systems

• 0G
• 1G
• 2G
• 3G
• 4G

1G is short for first‐generation wireless telephone technology. This generation of phones and networks is represented by the brick‐sized analog phones introduced in the 1980’s. Subsequent numbers refer to newer and upcoming technology.

2G phones use digital networks. Going all‐digital allowed for the introduction of digital data services, such as SMS and email. 2G networks and their digital nature also made it more difficult to eavesdrop on mobile phone calls.

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

4G (AKA Beyond 3G) is like the other generations in that its advantage lies in promised increased speeds 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 networks. The supposed speeds for 4G will be between 100 Mbit/s and 1 Gbit/s.

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