CDMA (Code Division Multiple Access) Technology

The world is demanding more from wireless communication technologies than ever before. More People around the world are subscribing to wireless services and consumers are using their phones more frequently. Add on features of Third-Generation (3G) wireless data services and applications - such as wireless email, web, digital picture taking/sending and assisted-GPS position location.

This is where CDMA (Code Division Multiple Access) technology fits in. CDMA consistently provides better capacity for voice and data communications than other commercial mobile technologies, allowing more subscribers to connect at any given time, and it is the common platform on which 3G technologies are built.

CDMA technology

Multiple Access : The concept behind multiple access is to permit a number of users to share a common channel. The two traditional ways of multiple access are Frequency Division Multiple Access (FDMA) and Time Division Multiple Access (TDMA).

FDMA : In Frequency Division Multiple Access, the frequency band is divided in slots. Each user gets one frequency slot. assigned that is used at will. It could be compared to AM or FM broadcasting radio where each station has a frequency assigned. FDMA demands good filtering.

TDMA : In Time Division Multiple Access, the frequency band is not partitioned but users are allowed to use it only in predefined intervals of time. one at a time. Thus TDMA demands synchronization among the users.

CDMA : CDMA, for Code Division Multiple Access, is different than those traditional ways in that it does not allocate frequency or time in user slots but gives right to use both to all users simultaneously. To do this, it uses a technique known as spread Spectrum. In effect, each user is assigned a code can recover it at the receiver end. This method has the property that the unwanted signals with different codes get spread even more by the process, making them like noise to the receiver.

Advantages of CDMA 2000

CDMA 2000 benefited from the extensive experience acquired through several years of operation of cdma-One systems. As a result. CDMA 2000 is a very efficient and robust technology. Supporting both voice and data, the standard was devised and tested in various spectrum bands, including the new IMT-2000 allocations.

There is tremendous demand for new services and operators are looking to provide these to many more subscribers at reasonable prices.

Due to its optimized radio technology, CDMA 2000 enables operators to invest in fewer cell sites and deploy them faster, ultimately allowinf the service providers to increase their revenues with faster Return on Investment (ROI). Increased revenues, along with a wider array of services, make CDMA2000 the technology of choice for services providers.

Other advantages of CDMA technology are increased Voice Capacity, Higher Data Throughput, Increased Battery Life, synchronization, Transmit Diversity.

Praise is the Professor and Head of the Dept of
Information Technology of
Calicut University. with more than 25 years of Professional Experience in
University of Calicut.