Low-Complexity Non-uniform Constellation Demapping Algorithm for Broadcasting System

This paper presents a novel low-complexity soft demapping algorithm for two-dimensional non-uniform spaced constellations (2D-NUCs) and massive order one-dimensional NUCs (1D-NUCs). NUCs have been implemented in a wide range of new broadcasting systems to approach the Shannon limit further, such as DVB-NGH, ATSC 3.0 and NGB-W. However, the soft demapping complexity is extreme due to the substantial distance calculations. In the proposed scheme, the demapping process is classified into four cases based on different quadrants. To deal with the complexity problem, four groups of reduced subsets in terms of the quadrant for each bit are separately calculated and stored in advance. Analysis and simulation prove that the proposed demapper only introduces a small penalty under 0.02dB with respect to Max-Log-MAP demapper, whereas a significant complexity reduction ranging from 68.75% to 88.54% is obtained.

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This work was supported by the grant No. 16511104204 The Research on Key Technologies of Multicast in Wireless LAN financed from the Shanghai Science and Technology Committee (STCSM), Research on Physical Layer Transmission Standard of Unidirectional Broadcast Channel for Next Generation Broadcasting and Television Wireless Network (No. 18DZ2203900) supported by Shanghai Technical Standard Project and Theoretical Research on New Dimensional Information Transmission Using Statistical Spectrum Characteristics of Wireless Communication Signals (No. 18XD1404100) supported by Shanghai Excellent Academic Leader Program, China.