Abstract: Multi-user communication system which combines means that implement the spread spectrum coding technique SSC with means that implement the modulation technique of orthogonal frequency-division multiplexing OFDM. This makes it possible to inhance the performance of the SSC system by simplifying certain data processing and data acquisition mechanisms.A preferred use is the use in telephone communication systems between mobile stations and base stations.

Abstract: Digital signal transmission system which operates by coded modulation of a constellation, the system comprising an encoder (5) which includes a modulator (13) installed at a transmitting station, and a decoder (105) which includes a demodulator (113) installed at a receiving station. A multistage channel encoder (12) carries out a concatenation of internal and external codes to blocks and divides the coding over various partitioning levels of the constellation. The coded symbol blocks are subjected to the work of a frequency-division interleaver (37), the modulator (13) operating according to an orthogonal carrier frequency-division multiplexing technique. The decoder (105) includes circuitry to carry out reverse operations to those carried out for the coding.