Enhanced LDM for Next-Generation Digital Broadcasting Transmission

Abstract

In the traditional layered division multiplexing (LDM) system, by simply adjusting the injection level, the reception performance of the core layer (CL) mobile services will be decreased significantly, resulting in the deterioration of system coverage performance. Thus, it is necessary to improve the performance of the enhanced layer (EL) service reception without affecting the reception threshold of CL service. To achieve this, in this paper, an enhanced LDM (En-LDM) scheme that supports multi-service transmission is proposed for the next-generation broadcasting network. In this scheme, at the transmitter end, part of the low-density parity-check (LDPC) coded data stream of fixed service conveyed in the EL will be extracted out through puncturing, and then, it will be transmitted over the CL of the LDM signal along with the original CL data in a frequency domain multiplexing (FDM) manner. At the receiving end, the punctured data of the EL fixed service will be recovered with a higher signal-to-noise ratio (SNR). Compared to the traditional LDM scheme, the proposed En-LDM scheme can significantly improve the reception performance of fixed services without decreasing the SNR threshold of mobile services. Moreover, the En-LDM can achieve a higher channel capacity than that of the traditional LDM for both the fixed services and the overall services. The superiority of the proposed En-LDM scheme over the traditional LDM scheme is validated by the simulation under the additive white Gaussian noise (AWGN) and fading channels.

Analysis on Fairness and Efficiency of the 3-PLP LDM System Using a Normalized Channel Capacity

“…In previous LDM research, many studies have been conducted to prove the superiority of LDM systems over TDM systems by setting specific injection levels and time ratios [5,23]. Figure 2 compares the LDM system with an injection level α and the TDM system with a time ratio τ [11,24]. The graph shows that the LDM system (represented by the red-line area) outperforms the TDM system (indicated by the red dot) regarding channel capacity for both PLP_1 and PLP_2 at a specific τ.…”

Biased-Power Allocation and Shared-Antenna Selection Techniques for Spatial Modulation-Based Layer Division Multiplexing Systems

“…Due to the importance and significance of the SINRs and the SMED factor, the suggested Bi-PA distributes the power ratios to obtain equal SINRs, and these SINRs take the SMED factor into mind. The UL receiver uses the ML detector in the SM-LDM receiver model described in Section 2 to estimate its information bits that are mapped to the modulation and spatial symbols, as shown in (2). The UL signal includes interference from the LL signal in addition to the AWGN with zero mean and variance σ 2 0 = 1/γ.…”

“…Layer division multiplexing (LDM) [1], a power-based non-orthogonal multiple access (NOMA) technology, is gaining popularity in a variety of wireless applications to deliver robust high-definition services [2][3][4]. Recently, the advanced television systems committee (ATSC) 3.0 standard applied LDM for broadcasting systems [5][6][7][8][9][10].…”

“…Alternatively, the LL, having better channel conditions, provides high data rate service for the fixed receiver via high modulation order techniques. In contrast to NOMA users, who are allowed to make use of the same kind of modulation strategy, LDM services must be delivered using a variety of alternative modulation constellations [1,2]. One example of this would be QPSK for UL and 64-QAM for LL.…”