How Does A CDMA Cell Phone Work?

Cell phones today are increasingly complex little packages, and those rates and minutes involved in the calling plans from the carriers are often far from simple themselves. But to fully explain a CDMA cell phone and how it works would take a very long time indeed, but for a simple glance at CDMA technology this is the place.

Code Division Multiple Access or CDMA cell phones are one type of digital phone, the cellular rival of this in the US has been TDMA (Time Division Multiple Access), now being supplanted by its sibling and global mobile cell phenomenon GSM, which originated in the world’s biggest cell phone market of Europe. And for how this works in simple terms you should check out the article: How Does A TDMA and GSM Cell Phone Work? As well as FDMA, CDMA, TDMA/GSM Cell Phone Technology - A Simple Explanation Of The Differences.

But here we deal with CDMA cellular phones, and for a first look at how cell phones use their system of hexagonal grids so that we can continue our conversations as we travel, check out this article; How Does A FDMA Cell Phone Work?

Digital cell phones have replaced analog cell phones in all urban areas now, because of greater bandwidth capacity and other advantages for both the cell customers and the cellular carriers, and CDMA works by using this range of cellular frequencies in entirely new ways.

What happens in when your mobile phone handset is a CDMA phone, the voice or data calls are spread out across the entire available wireless frequency bandwidth and use frequencies 1.25MHz wide, rather than being allocated channels either by time or frequency.

This might seem unlikely as surely everything would merge into one cellular mess and totally lose any semblance of order. Well it would if not for the important code part of that name, code division multiple access (CDMA).

The cellular information of either voice or other data (like picture messaging for example) is split up into small packets and transmitted to the recipient in binary code of 1s and 0s (or it wouldn‘t be digital), and each packet has a spread code embedded within it. This cellular phone code is exclusive to each cell user and call, and every packet of data can therefore be assigned correctly when being reassembled at the receiving cell phone and all other data with different codes is ignored.

Also referred to as wide band spread spectrum, CDMA cellular encoding makes sure that all the cellular transmitted data is correctly recognized and duly assigned, without interference from all the other cell phone signals which all have their own individual codes to be recognized.

Interference from other cellular users within the system is not a problem unless the number of phone users reaches a saturation point which disrupts the voice coding system.

Another thing about CDMA cellular technology is that more than one (actually three) cell phone towers can be used at any one time, as the cell phone can choose which site is giving the best signal, or choose to blend the signal from two or more. This cell phone process is known as `soft handoff’ and is an ability unique to CDMA cell phones.

Also see; cell phone FAQ.

Author Notes:

Matt Jacks contributes and publishes news editorial to http://www.cell-phones-n-plans.com. A cell phone industry resource that features service plan comparisons, cellular phone reviews and articles.