Efficient Decoding of LDM Core Layer at Fixed Receivers in ATSC 3.0

Abstract

In order to decode an enhanced layer (EL) signal for a layered-division multiplexing (LDM) system at fixed receivers in ATSC 3.0, low-density parity-check (LDPC)/BCH decoding and successive interference cancellation should be performed to eliminate the core layer (CL) signal. For a high signal-to-noise ratio environment and sufficient low injection level of the EL signal, the CL bit-interleaved coded modulation decoder can easily achieve quasi error free for the whole LDPC codeword. However, for high injection levels, there may be still many erroneous bits in the parity part even after LDPC/BCH decoding since the ATSC 3.0 LDPC codes have the characteristic of unequal error protection due to the unequal weight distributions in their parity-check matrices. Therefore, ATSC 3.0 receivers should include re-encoding module for CL LDPC codes to completely recover the CL signal for LDM system. In this paper, we propose an efficient method to reconstruct CL signal in ATSC 3.0 LDM systems, which can be realized by a modified re-encoding after LDPC decoding of the CL signal. It significantly reduces the computational complexity and worst case latency without any loss of coding performance.