CDMA is a channel access method used by various radio communication technologies. CDMA is an example of multiple access, where several transmitters can send information simultaneously over a single communication channel. This allows several users to share a band of frequencies. To permit this without undue interference between the users, CDMA employs spread-spectrum technology and a special coding scheme where each transmitter is assigned a code. CDMA is used as the access method in many mobile phone standards such as cdmaOne, CDMA2000, and WCDMA, which are often referred to as simply CDMA.