Modulation and coding for ATSC 3.0

In this paper we summarize and expound upon the choices made for the BICM (Bit-Interleaved and Coded Modulation) part of the next-generation terrestrial broadcast standard known as ATSC 3.0. The structure of the ATSC 3.0 BICM consists of a forward error correcting (FEC) code, bit interleaver and constellation mapper. In order to achieve high efficiency over a wide range of reception conditions and Carrier-to-Noise (C/N) ratio values, several notable new elements have been standardized. First, twenty four original Low-Density Parity Check (LDPC) codes have been designed, with coding rates from 2/15 (0.13) up to 13/15 (0.87) for two code sizes: 16200 bits and 64800 bits. Two different LDPC structures have been adopted; one structure more suited to medium and high coding rates and another structure suited to very low coding rates. Second, in addition to QPSK, Non-Uniform Constellations (NUCs) have been chosen for constellation sizes from 16QAM to 4096QAM to bridge the gap to the Shannon theoretical limit. Two different types of NUCs have been proposed: one-dimensional NUCs (1D-NUC) for 1024- and 4096-point constellations, and two-dimensional NUCs (2D-NUCs) for 16-, 64- and 256-point constellations. 2D-NUCs achieve a better performance than 1D-NUCs but with a higher complexity since they cannot be separated into two independent I/Q components. Each NUC has been optimized for the particular code and coding rate, although for the shorter code length the constellations have been limited up to 256QAM. Finally, a bit interleaver, optimized for each NUC/coding rate combination, has been designed to maximize the performance. This paper describes the coding, modulation and bit interleaving modules of the BICM block of ATSC 3.0, and compares its performance with other DTT standards such as ATSC A/53 and DVB-T2.