CDMA - definition

CDMA (Code Division Multiple Access) is a wireless communication technology used to transmit signals over a shared frequency band. Being a digital spread-spectrum technology, CDMA spreads the signal over a larger bandwidth than is required to transmit the data. As a result, numerous users can simultaneously share the same frequency band yet each user's signal can be distinguished from the others.
Each CDMA subscriber is given a unique code that is used to distribute the signal across the frequency range. The same code is used by the receiver to demodulate the signal and retrieve the original data. Compared to other wireless communication technologies like the GSM (Global System for Mobile Communications), CDMA is able to offer more capacity and security since each user has a specific code.
Mobile phones, wireless data networks, satellite communications, and other wireless communication systems all employ CDMA technology. The 3G and 4G mobile phone networks employ CDMA, which is still in use in some locations where it is not yet practical to build more recent technologies like LTE (Long Term Evolution).