code division multiple access (CDMA)

Digital cellular phone technology that (unlike Global System For Mobile Communication or GSM) does not partition the available bandwidth to assign a separate frequency to each call. Instead, it assigns the entire bandwidth to one call and encodes each call in a manner that only the intended receiver can decode it. Since encoding filters out the background noise and a wide bandwidth allows more data to be sent in the same period, it promises clear, fast, and interference-free communication. Out of its several versions, version 1X provides a 1.25 megahertz (MHz) bandwidth, and version 3X a 5 MHz bandwidth. Invented during World War 2 to evade jamming of Allied forces signals by Germany, it was developed for cellular use by the US company Qualcomm which owns most of its patents and all licensing rights. See also TDMA.