How does Code-Division Multiple Access (CDMA) function in telecommunications?

Code-Division Multiple Access (CDMA) functions by allowing multiple users to share the same frequency simultaneously through the use of unique codes for each user. This method differentiates the individual signals of different users, making it possible for their transmissions to overlap in both time and frequency while remaining distinct from one another. Each user's signal is encoded with a unique spreading code, which not only enhances the system's capacity to accommodate more users but also improves resilience to interference and enhances signal security.

This is fundamentally different from the operation of other access techniques. For example, some methods rely on time slots, which means only one user can transmit at a given time. In contrast, CDMA allows all users to communicate concurrently, maximizing the utilization of available spectrum and resulting in efficient bandwidth use. This simultaneous sharing is one of the key advantages of CDMA in telecommunications, particularly evident in mobile networks where users can connect without waiting for a dedicated channel.