Joint preamble and code rate identifier in a mobile DTV system

摘要

A joint preamble and code rate identifier flag in a reserved portion of a data field synchronization segment in a digital television (DTV) data field identifies the presence of preamble training data in a forward error correction (FEC) encoded portion of the DTV data field. The identifier flag also indicates the code rate used for the data field. The data field synchronization segment is not FEC encoded, thereby allowing detection of the identifier flag without FEC decoding. The detection at a receiver of the identifier flag in a DTV data field allows receiver elements, such as an equalizer and a FEC decoder, to more readily obtain and utilize the preamble training data, thereby enhancing reception and/or simplifying receiver design.

主权项

1. A method performed by an apparatus to receive and process forward error correction (FEC) encoded video data in a mobile digital television (DTV) data burst, the method comprising:
detecting a joint identifier flag in a reserved portion of a data field of the data burst, wherein the joint identifier flag indicates whether the data field contains preamble training data and provides a code rate associated with data in the data burst, wherein said data burst contains a plurality of data fields, said reserved portion is not FEC encoded, and said preamble training data comprises a plurality of packets and is FEC encoded; performing equalization of the FEC encoded video data by an equalizer using the preamble training data, said preamble training data being used to train the equalizer before processing of subsequent FEC encoded video data; and performing iterative FEC decoding of the FEC encoded video data by an iterative FEC decoder using the preamble training data and the code rate, said preamble training data being used to train the iterative FEC decoder before processing subsequent FEC encoded video data.