06-09-2012, 05:00 PM
Wireless Network Communication
1Wireless Network.ppt (Size: 4.73 MB / Downloads: 50)
Introduction
In wireless communication, the communication link is established through radio frequencies (RF).
The telecommunication system go through a number of wired segments for setting up a wireless communication session between two users.
Radio Frequency
Spectrum
The entire range of waves is referred to as a spectrum.
Band
Band refers to a range of RFs usable for a particular task which can
be transporting data or voice or something else.
To describe the size of this band, the term bandwidth is used.
For example, if a particular device can use RF between 80 and 180 MHz
to perform a task
bandwidth= 180 - 80 = 100 MHz.
ii Compute the average: (80 + 180)/2 = 130 MHz.
iii Divide the bandwidth by the average frequency and multiply the result by 100:
(100 t 130) x 100 = 76.92%.
The International Telecommunication Union (ITU) identified 11 bands for radio frequencies ranging from 3 Hz to 300 GHz.
Foot Print
A cell in real life is highly amorphous, and its actual radio coverage is referred to as footprint.
A real footprint is determined with some field measurement or through wave propagation prediction models, but in theory a well-defined regular shape is required to compute the necessary parameter values.
Broadband
Broadband category is designed to offer two-way voice, data, and video communications.It has been referred to as “the next generation of mobile telephone service.”
Broadband Personal Communication Service(PCS) is allocated spectrum ranging from 1 850 to 191 0 MHz and 1930 to 1990 MHz.
This 120 MHz of spectrum was divided into six frequency blocks A through F where blocks A, B, and C are 30 MHz each, and blocks D, E, and F are 10 MHz each. Different wireless services are provided under each of these bands.