CODE DIVISION MULTIPLE ACCESS (CDMA) DEFINITION BASIC INFORMATION AND TUTORIALS

What Is CDMA?


Code Division Multiple Access (CDMA) is often referred to as the most interesting, but hardest to implement method of carrying wireless services. CDMA systems have no channels, but instead encode each call as a coded sequence across the entire frequency spectrum. Each conversation is modulated, in the digital domain, with a unique code that makes it distinguishable from the other calls in the frequency spectrum.

CDMA is the newest of the multiple access technologies; it is not yet as widely used but is showing great promise. CDMA does not divide the allocated block of frequencies into individual channels. It assigns a unique code to each signal and then combines all the signals into a single large channel.

The receiver receives the integrated signal and uses the same code just to process the desired signal. CDMA is gaining popularity as a third-generation (3G) wireless phone technology because it is very efficient at utilizing bandwidth, plus it is natively very secure because all conversations are uniquely encoded.

The fact that CDMA shares frequencies with neighboring wireless towers allows for easier installation of extra capacity, since extra capacity can be achieved by simply adding extra cell sites and shrinking power levels of nearby sites.The downside to CDMA is the complexity of deciphering and extracting the received signals, especially if there are multiple signal paths (reflections) between the phone and the wireless tower (called multipath interference).

As a result, CDMA phones are sometimes more expensive than other digital phones and CDMA antenna site equipment is three to four times the price of the other digital network equivalents.


Benefits of CDMA
CDMA networks cover more wireless users in the United States than any other digital standard and include benefits such as:

Advanced features like caller ID, text messaging

Voice clarity and overall call quality

The ability to filter out background noise and interference

Fewer dropped calls (as compared to analog)

Improved security and privacy—the digitally encoded, spread spectrum transmissions minimizes eavesdropping

Α large number of customers who can share the same radio frequencies

The greatest customer capacity of network equipment for low cost

Less battery power (when compared to analog)