Digital sound broadcasting to mobile receivers

The authors describe a system that combines the orthogonal frequency-division multiplexing technique and a coding strategy associated with diversity in the frequency domain. The system is suitable for digital broadcasting through a particularly hostile urban radio channel. The general principles of COFDM (coded orthogonal frequency-division multiplexing) are explained, and a detailed representation of the signals and the decoding procedure is given. The performance of the system in the selective Rayleigh channel is presented, and the behavior of the system when the conditions of temporal and frequency coherence of the channel are not fully met (very high-speed reception and abnormally extended channel delay spread) is described. The first implementation of a 4-PSK-COFDM systems has been demonstrated at the WARC-ORB 88 conference in Geneva, validating this concept of digital sound broadcasting