code-division multiple access

Code-division multiple access (CDMA) is a method for sharing a communications channel among multiple users. In CDMA, signals are transmitted simultaneously within the same frequency band. Each user is assigned a unique "spreading code" that acts as a signature waveform. Receivers use this code to identify and select the desired signal while rejecting others.1

This technique is also known as spread-spectrum multiple access (SSMA) because the code sequence spreads the signal's power over a larger bandwidth. A key advantage of CDMA is that it eliminates the need for frequency management required in other methods like FDMA. When a new user needs to access the channel, they are assigned a code and can transmit immediately without waiting for a specific frequency slot to become available.1