High-quality audio and video signal transmission in a broadband ISDN based on ATD-the problem of cell losses

In a broadband ISDN (integrated services digital network) based on the asynchronous time-division (ATD) multiplexing technique, cell losses occur which have an adverse effect on the quality of service, particularly on high-quality video and audio signals. A method is described which allows a complete correction of the cell losses. This goal is achieved by combining a forward error correction with a bit interleaving technique on the basis of the (5+48)-byte cell format recommended by the CCITT. Hardware solutions found for terminal adaptors for high-quality video and audio signals implemented in a demonstration model of the European RACE project 1022 are described. The special problem of clock recovery in the cell-structured transmission of signals at constant bit rates is treated in more detail