How Cellphone Works?
As an aspirant cellphone Technician, It is fully advice that you must posses a basic knowledge of handset technology and its components. In many parts of the world, mobile phones have become such a part of everyday life one wonders how we ever managed without them. For world travelers, mobile phones can offer some incredible benefits. However, they also present certain challenges, not the least of which is whether they will even work when traveling from one place to another.
Store contact information
Make task or to-do lists
Keep track of appointments and set reminders
Use the built-in calculator for simple math
Send or receive e-mail
Get information (news, entertainment, stock quotes) from the Internet
Play games
Watch TV
Send text messages
Integrate other devices such as PDAs, MP3 players and GPS receivers
These days, cell phones provide an incredible array of functions, and new ones are being added at a breakneck pace. Depending on the cell-phone model, you can:
Before we procced further, please take a simple brief to inhanced your knowlegde about the Field of What we are going to discuss hereafter.... Now first come first we all ever wonder how does the cellphone works? have you ever wondered how a cell phone works? What makes it different from a regular phone? what's inside of it and how do they created it? What do all those terms like PCS, GSM, CDMA and TDMA mean?To start with, one of the most interesting things about a cell phone is that it is actually a radio -- an extremely sophisticated radio, but a radio nonetheless. The telephone was invented by Alexander Graham Bell in 1876, and wireless communication can trace its roots to the invention of the radio by Nikolai Tesla in the 1880s (formally presented in 1894 by a young Italian named Guglielmo Marconi). It was only natural that these two great technologies would eventually be combined.If you prepare to take a deep knowledge, i recommended you to visit this site and have a brief of Fundamentals of Wireless Communication.
A basic technician all need is just to have a simple understanding about cellphones, we do not need extreme and intimate deeper meaning about it, that's because what we are going to take around here is to fix what those various mobile phones company created and build....to make it as simple as that... We are going to fix somewhat if their product gets busted by the end user's who bought it... below is just a simple basic information I gathered to compensate somewhat of what we are going to learn.Cell Phone Network Technologies:
Cell-phone Frequencies
In the dark ages before cell phones, people who really needed mobile-communications ability installed radio telephones in their cars. In the radio-telephone system, there was one central antenna tower per city, and perhaps 25 channels available on that tower. This central antenna meant that the phone in your car needed a powerful transmitter -- big enough to transmit 40 or 50 miles (about 70 km). It also meant that not many people could use radio telephones -- there just were not enough channels.
The genius of the cellular system is the division of a city into small cells. This allows extensive frequency reuse across a city, so that millions of people can use cell phones simultaneously.
A good way to understand the sophistication of a cell phone is to compare it to a CB radio or a walkie-talkie.
Full-duplex vs. half-duplex - Both walkie-talkies and CB radios are half-duplex devices. That is, two people communicating on a CB radio use the same frequency, so only one person can talk at a time. A cell phone is a full-duplex device. That means that you use one frequency for talking and a second, separate frequency for listening. Both people on the call can talk at once.
Channels - A walkie-talkie typically has one channel, and a CB radio has 40 channels. A typical cell phone can communicate on 1,664 channels or more!
Range - A walkie-talkie can transmit about 1 mile (1.6 km) using a 0.25-watt transmitter. A CB radio, because it has much higher power, can transmit about 5 miles (8 km) using a 5-watt transmitter. Cell phones operate within cells, and they can switch cells as they move around. Cells give cell phones incredible range. Someone using a cell phone can drive hundreds of miles and maintain a conversation the entire time bec ause of the cellular approach.
In half-duplex radio, both transmitters use the same frequency. Only one party can talk at a time.
In full-duplex radio, the two transmitters use different frequencies, so both parties can talk at the same time.
Cell phones are full-duplex.
Originally utilizing the 900 Mhz spectrum, GSM providers in parts of Europe, Africa, and Asia later added additional capacity at 1800 Mhz. In North America, however, GSM service operates at 850 Mhz or 1900 Mhz. The good news for world travelers is that most cell phone manufacturers offer dual-band (900 and 1900 Mhz), tri-band (900, 1800 and 1900 Mhz) and a growing number of quad-band (800, 900, 1800 and 1900 Mhz) phones that will work practically anywhere GSM systems are found.
Each cell has a base station that consists of a tower and a small building containing the radio equipment. We'll get into base stations later. First, let's examine the "cells" that make up a cellular system.
