DATA TRANSMISSION SYSTEM

摘要

The invention relates to a Digital Video Broadcasting system comprising. The system comprises a service provider (5a, 5b) for generating first digitally coded information; said digitally coded information being coded according to a first code; a broadcast network provider (15) having an input for receiving said first digitally coded information, said broadcast network provider (15) comprising a protocol stack having an MPEG2 TS layer (321) below an IP layer (330a); said broadcast network provider (15) being arranged to encapsulate digitally coded information into MPEG-2 TS packages, and an FEC layer (323) between said IP layer (330a) and said MPEG-2 TS layer (321), said broadcast network provider (15) further comprising means for calculating FEC parity information dependent on said received first digitally coded information; means for generating second digitally coded information; said second digitally coded information comprising said first digitally coded information and said FEC parity information; andan output for delivering said second digitally coded information; said second digitally coded information comprising an application data table (601) containing IP datagrams, and an RS data table (602) containing said FEC parity information, arranged such that said IP datagrams are extractable without use of said FEC parity information; a relay arrangement (16; 18) for receiving said second digitally coded information and for relaying said second digitally coded information; a receiving unit (20, 21; 24, 25; 28) for receiving digitally coded information; said receiving unit (20, 21; 24, 25; 28) comprising a protocol stack having an MPEG-2 TS layer (321) below an IP layer (330a); and an FEC layer (323) between said IP layer (330a) and said MPEG-2 TS layer (321); said receiving unit (20, 21; 24, 25; 28) further comprising means for extracting FEC parity information from the received digitally coded information; means for extracting a unit of information corresponding to said first digitally coded information; wherein said unit of information may contain erroneous information so that said unit of information is non-identical to said first digitally coded information; means for generating third digitally coded information in dependence on said unit of information and said extracted FEC parity information.