In this technology communication can take place in several directions. It provides anywhere, anytime communications. In wireless system a low energy radio waves on a local antenna site connect the user to make a link with a destination node. In mobile communication a computerized system monitors each call.
Wireless technology is based upon two methods:
- Radio Based System
- Light Based System
Radio Based System: It include land based wireless or satellite based wireless systems. In this system radio frequency signals travel over frequencies from 100 KHz to 20 GHz. Radio Frequency signals may be local or wide, depend upon frequency ranges. Radio frequency communication is 10 miles while 2 way cover 6 miles.
In land based radio system data is receive and send at low powers transmitter and receivers. Land based system rely upon private packet networks, circuit switched cellular services and so on.
In satellite based system a global communication take place. This system is ideal for broadcast applications. Every satellite receive signals from a set of frequency, amplifies them and again retransmit to another frequency.
It is very reliable communication. It is useful to disperse or gathered the data from many remote nodes. It is also inexpensive.
Light Based System: It is based upon the infrared waves. In light based system light pulses are sending by a light emitted diode (LED) to a photo sensor which decodes the signals. For light based system no physical interruption take place for sending and receiving data.
For transformation of data infrared equipment are required which can be of low or high speed. A low speed device range is from 115 to 250 Kbps and a high speed device range is above 500 Kbps and data transfer rate is about 1.25 megabytes per second.
Infrared devices also used with RF transceivers, which transfer data within a 10 meter range. Infrared system is not expensive. It is used in transmission of data, updating of files, downloading schedules etc.
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