Réseaux cellulaires

The first CDMA system, originating in the USA (IS-95 standard), is a broadband technique in which the radio-frequency spectrum is divided into channels approximately 1.23 MHz wide. Traffic channels are obtained by assigning each user a unique code within that channel. Each user signal is then spread over the full width of the channel for transmission.

One of the special features of the CDMA system is that, although there are naturally limits to the traffic capacity of a given channel, these limits are not fixed. System capacity will depend on a number of factors that the network operator can control.