TAILIEUCHUNG - Non-uniform constellations for ATSC 3.0

This paper introduces the concept of a nonuniform constellation (NUC) in contrast to conventional uniform quadrature-amplitude modulation (QAM) constellations. Such constellations provide additional shaping gain, which allows reception at lower signal-to-noise ratios. will be the first major broadcasting standard, which completely uses NUCs due to their outstanding properties. We will consider different kinds of NUCs and describe their performance: 2-D NUCs provide more shaping gain at the cost of higher demapping complexity, while 1-D NUCs allow low-complexity demapping at slightly lower shaping gains. These NUCs are well suited for very large constellations sizes, such as 1k and 4k QAM. | IEEE TRANSACTIONS ON BROADCASTING VOL. 62 NO. 1 MARCH 2016 197 Non-Uniform Constellations for ATSC Nabil Sven Loghin Jan Zollner Belkacem Mouhouche Daniel Ansorregui Jinwoo Kim and Sung-Ik Park Senior Member IEEE Abstract This paper introduces the concept of a nonuniform constellation NUC in contrast to conventional uniform quadrature-amplitude modulation QAM constellations. Such constellations provide additional shaping gain which allows reception at lower signal-to-noise ratios. will be the first major broadcasting standard which completely uses NUCs due to their outstanding properties. We will consider different kinds of NUCs and describe their performance 2-D NUCs provide more shaping gain at the cost of higher demapping complexity while 1-D NUCs allow low-complexity demapping at slightly lower shaping gains. These NUCs are well suited for very large constellations sizes such as 1k and 4k QAM. Index Terms Non-uniform constellations constellation shaping QAM terrestrial broadcast. I. Introduction The transition from first to second generation digital terrestrial broadcast systems such as transition from DVB-T to DVB-T2 1 offered a variety of new technologies and algorithms which reduced the gap to the famous Shannon limits 2 . One major trend was the adoption of more powerful forward error correction FEC schemes. Cuttingedge low-density parity-check LDPC codes together with an outer BCH code replaced the long established combination of a convolutional code with an outer Reed-Solomon RS code. Similar data throughput was thus achieved at about 5dB less signal-to-noise ratio SNR 3 . Subsequent activities to further improve FEC schemes resulted in minor additional gains in the order of . Larger FEC gains were obtained at the price of higher complexity . by LDPC parity check matrices with higher density and or longer codeword lengths. Obviously the new FEC schemes were already close to optimum. In order to further increase Manuscript

• Kĩ thuật Viễn thông
• Terms—Non uniform constellations
• Constellation shaping
• Terrestrial broadcast
• Quadrature amplitude modulation
• Lower signal to noise ratios