Base Band inter-frame FEC (BB-iFEC) for Next Generation Handheld DVB-NGH

This paper describes a novel Forward Error Correction (FEC) and time interleaving scheme, known as BB-iFEC (Base Band inter-frame FEC), proposed for the next generation mobile broadcasting standard DVB-NGH. BB-iFEC is a new generation of physical layer FEC that aims to provide long time interleaving with fast zapping support. The starting point for the development of DVB-NGH is the DVB-T2 physical layer. BB-iFEC introduces an outer FEC and an outer time interleaver which are concatenated to the (inner) LDPC FEC code and (inner) time interleaver of DVB-T2. BB-iFEC is based on the link layer FEC scheme of DVB-SH MPE-iFEC (Multi Protocol Encapsulation inter-burst FEC), but moved down to the physical layer. This allows full transparency towards upper layers, as well as reduced signalling overhead and packet fragmentation. However, the major novelty of BB-iFEC is that it allows re-using the soft information at the output of the inner LDPC decoder (i.e., the log-likelihood ratios, LLRs). This allows improving the performance, at the expense of higher memory requirements at the receivers. Instead of the Reed-Solomon code adopted in MPE-iFEC for erasure decoding, BB-iFEC re-uses the LDPC code of DVB-T2, which allows to perform either soft or hard decoding, being thus a scalable solution.