Wireless networks operate in a network that divides the city or region into cells smaller. One cell covers several city blocks or up to 250 square miles. Each cell uses a set of radio frequencies or channels to provide services in specific areas. The strength of this radio to be controlled to limit the geographic reach of the signal. Hence, the same frequencies can be reused in nearby cells. So many people can have conversations simultaneously in different cells in the entire city or region, even though they are in one channel.
In each cell, there are basic station that contains the wireless antennas and other radio equipment. Wireless antenna in each cell will menghbungkan caller to the local telephone network, Internet, or other wireless networks. Mentransimiskan wireless antenna signal. When the cell phone turned on, the phone will look for a signal to confirm that the service is already available. Then the phone transmits certain identification numbers, so the network can verify information such as customer-service provider of wireless, and phone numbers.
* Calls from mobile phones to call home
When making calls from mobile phones to a regular home phone, the call is walked in through a nearby wireless antenna and will be modified by penghantar wireless to traditional landline phone system. The call will then be directed to the traditional telephone network and to the people who call destination.
* Calls from Phone to Phone Handheld Handheld
When making a call from this, the call will be routed through the landline network to the introduction of wireless receiver or wireless network will be routed to the nearest cell with a person who is the purpose of the call. At the time talking on cell phones, the mobile phone will capture the sound and change the sound into radio frequency energy (radio waves). radio waves will go through the air to find the nearest base station receiver. Base station then sends the call through a wireless network up to the person who is the destination phone.
* Long-distance calls
when making a call to someone who is very far away, the call will be routed to the central exchange distant history, which connect calls between countries or around the world via fiber optic cable.
Source : http://id.wikipedia.org/wiki/Telepon_selular#Cara_kerja