Digital radio - OFDM modulation

At a time when digital is supplanting analog in all image and sound transfer techniques, the sound broadcasting sector is a rather special case, insofar as the two modes seem to have found a state of equilibrium in cohabitation. Having taken the gamble that analog cannot endure in the face of the inescapable thrust of digital, the authors propose to open a dossier highlighting the relative prospects for the evolution of an exclusively digital radio.

This dossier, concerning only the last segment of a radio production/distribution chain, which goes from a point of transmission to the receiving terminal, is made up of 4 articles:

• [TE 6 140] provides a brief history of radio, and describes the technical platforms and networks that can be used for analog and then digital radio. It then presents a brief overview of the technical systems developed for broadcasting or transmitting digital radio, and compares their different uses depending on the distribution platform;

• [TE 6 142] presents the main techniques common to all digital radio systems: audio source coding (in particular MPEG-4 HE-AAC), frame formatting and multiplexing, and data protection through error detection-correction and interleaving. This related article presents COFDM digital modulation;

• [TE 6 150] details the first broadcast standard developed, DAB (Digital Audio Broadcasting) and its 2nd generation, DAB+, as well as T-DMB (Terrestrial – Digital Multimedia Broadcasting), derived from DAB but extended to broadcast video to mobiles;

• [TE 6 154] exposes other digital radio broadcasting systems via other technical platforms and networks:...