CODE DIVISION MULTIPLE ACCESS (CDMA)

A coding scheme, used as a modulation technique, in which multiple channels are independently coded for transmission over a single wideband channel . ( 188 ) Note 1: In some communication systems, CDMA is used as an access method that permits carriers from different stations to use the same transmission equipment by using a wider bandwidth than the individual carriers. On reception, each carrier can be distinguished from the others by means of a specific modulation code , thereby allowing for the reception of signals that were originally overlapping in frequency and time . Thus, several transmissions can occur simultaneously within the same bandwidth, with the mutual interference reduced by the degree of orthogonality of the unique codes used in each transmission . Note 2: CDMA permits a more uniform distribution of energy in the emitted bandwidth .