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electronics.howstuffworks.com/cell-phone8.htm

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Posted by saqlain231

try this
forums.travel.com/verizon-cell-phones-wireless-forum/756185-automatic-automatic-b-explain-please.html - 62k -

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Posted by waqasahmad

http://www.gizmocafe.com/handhelds/parents-cell-guide/cell-networks-explained.aspx

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Posted by jahangir1983

http://www.gizmocafe.com/handhelds/parents-cell-guide/cell-networks-explained.aspx

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Posted by jahangir1983

http://www.gizmocafe.com/handhelds/parents-cell-guide/cell-networks-explained.aspx

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Posted by jahangir1983

Frequnce assignment method in which a band frequncy is assignend to certain company.

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Posted by waqqas1

http://www.gizmocafe.com/handhelds/parents-cell-guide/cell-networks-explained.aspx

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Posted by Hash007

All cellular phone networks worldwide utilize a portion of the radio frequency spectrum designated as Ultra High Frequency, or "UHF", for the transmission and reception of their signals. The UHF band is also shared with Television, Wi-Fi and Bluetooth transmission. The cellular frequencies are the sets of frequency ranges within the UHF band that have been allocated for cellular phone use.

Due to historical reasons, radio frequencies used for cellular networks differ in the Americas, Europe, and Asia. The first commercial standard for mobile connection in the United States was AMPS, which was in the 800 MHz frequency band. In Europe, the first wide-spread automatic mobile network was based on the NMT-450 standard, which was in the 450 MHz band. As mobile phones became more popular and affordable, mobile providers encountered a problem because they couldn't provide service to the increasing number of customers. They had to develop their existing networks and eventually introduce new standards, often based on other frequencies. The GSM standard, which appeared in Europe to replace NMT-450 and other standards, initially used the 900 MHz band. As demand grew, carriers acquired licenses in the 1800 MHz band. (Generally speaking, lower frequencies allow carriers to provide coverage for a larger area, while higher frequencies allow carriers to provide service to more customers in a given area.)

In the U.S., the analog AMPS standard that used the Cellular band (800 MHz) was replaced by a number of digital systems. Initially, systems based upon the AMPS mobile phone model were popular, including IS-95 (often known as "CDMA", the air interface technology it uses) and IS-136 (often known as D-AMPS, Digital AMPS, or "TDMA", the air interface technology it uses.) Eventually, IS-136 on these frequencies was replaced by most operators with GSM.

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Posted by sagitraz