A Near-Capacity MIMO Coded Modulation Scheme for Digital Terrestrial Television Broadcasting

Abstract

Multiple-input multiple-output (MIMO), which can provide ultrahigh data transmission rate, is one of the key technologies for the next generation digital terrestrial television broadcasting (DTTB) standards. This paper proposes a near-capacity MIMO bit-interleaved coded modulation scheme with either independent or iterative demapping (BICM/BICM-ID) for the DTTB system. First, the amplitude phase shift keying (APSK) constellation with Gray mapping is proposed to replace the conventional Gray quadrature amplitude modulation (QAM) counterpart. From the perspective of average mutual information analysis, Gray-APSK has certain shaping gain compared to Gray-QAM for both independent and iterative demapping schemes. Besides the APSK constellation, a novel bit interleaver named bit mapping, which takes into account the unequal error protection of both APSK constellations and low-density parity-check codes, is proposed to further improve the system performance. The tool of extrinsic information transfer chart is utilized to analyze and design the optimal bit mapping for the BICM/BICM-ID scheme. Bit error rate simulations are finally carried out to verify the superiority of the proposed MIMO coded modulation scheme.