A novel ATM based data transport system for hybrid fiber coax CATV networks

In this article, a transport system for use on hybrid fiber coax (HFC) cable television (CATV) networks is described. The system delivers an effective bitrate of 35 Mbps in the downstream direction and an effective bitrate of 2.1 Mbps in the upstream. The system uses asynchronous transfer mode (ATM) technology as transport mechanism, while time division multiple access (TDMA) is used to create a multiple access environment in the upstream direction. Timing aspects related to the use of TDMA in the upstream such as round trip delay and time slot synchronization are discussed in this paper. In the downstream direction forward error correction according to the DVB specification is applied, while in the upstream direction each burst is exactly one ATM cell plus 4 FEC bytes. ATM connections between users and servers as well as the encryption applied in the system are discussed. The described transport system is currently implemented in several prototypes and will be demonstrated mid 1997 in four European field trials within the framework of the ACTS project ATHOC.