LLR Reliability Improvement for Multilayer Signals

Regueiro, Cristina; Barrueco, Jon; Montalbán, Jon; Angueira, Pablo; Ordiales, J.L.; Vélez, Manuel

doi:10.1109/tbc.2016.2617280

Cited by 5 publications

(10 citation statements)

References 15 publications

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“…It was observed that at high SNR regions, the I-curves for the top-layer signal are reduced compared to QPSK + QPSK signal. This behavior refuses the conclusion extracted from [71]. The obtained results are not provided in this section, but performance results are presented and discussed in Section 2.4.…”

Section: I-curvessupporting

confidence: 72%

“…However, they are usually operational points to be avoided in service deployments. In [71], the impact of the x b constellation onto x t performance was only observed at practical regions for LDM operation, so that the system was only AWGN limited. The OD gains with respect to GD when either a QPSK or a 64NUC is used for the x b are summarized in Table 2…”

Section: Performance Analysismentioning

confidence: 99%

“…However, LDM can be implemented with more layers. An information-theoretic analysis for the N -layer case has been introduced in [118], as well as initial performance simulations for 3-layer case in [71], [118]. Nevertheless, laboratory results as well as eld trials should be further evaluated.…”

Section: N-ldm and Ldm Segmentationmentioning

confidence: 99%

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Advanced Layered Divsion Multiplexing Technologies for Next-Gen Broadcast

Crevillén¹

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Since the beginning of the 21st century, terrestrial broadcasting systems have been blamed of an inecient use of the allocated spectrum. To increase the spectral eciency, digital television Standards Developing Organizations (SDOs) settled to develop the technical evolution of the rst-generation Digital Terrestrial Television (DTT) systems. Among others, a primary goal of nextgeneration DTT systems (European DVB-T2 and U.S. ATSC 3.0) is to simultaneously provide TV services to mobile and xed devices. The major drawback of this simultaneous delivery is the dierent requirement of each reception condition. To address these constraints dierent multiplexing techniques have been considered. While DVB-T2 fullled the simultaneous delivery of the two services by Time Division Multiplexing (TDM), ATSC 3.0 adopted the Layered Division Multiplexing (LDM) technology. LDM can outperform TDM and Frequency Division Multiplexing (FDM) by taking advantage of the Unequal Error Protection (UEP) ratio, as both services, namely layers, utilize all the frequency and time resources with dierent power levels. At receiver side, two implementations are distinguished, according to the intended layer. Mobile receivers are only intended to obtain the upper layer, known as Core Layer (CL). In order not to increase their complexity compared to single layer receivers, the lower layer, known as Enhanced Layer (EL) is treated as an additional noise on the CL decoding. Fixed receivers, increase their complexity, as they should performed a Successive Interference Cancellation (SIC) process on the CL for getting the EL. To limit the additional complexity of xed receivers, the LDM layers in ATSC 3.0 are congured with dierent error correction capabilities, but share the rest of physical layer parameters, including the Time v

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Section: I-curvessupporting

confidence: 72%

Section: Performance Analysismentioning

confidence: 99%

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Advanced Layered Divsion Multiplexing Technologies for Next-Gen Broadcast

Crevillén¹

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“…Hence, potential performance gains may be achieved if this effect is considered. This paper expands the initial studies in [6] of a demapping approach for LDM systems in which the AWGN-like interference assumption may not be valid. This new demapping approach considers the distribution of the symbols of the underlying LDM layer when demapping the top-layer signal, which brings a potential gain under certain circumstances at the expense of additional complexity.…”

Section: Introductionmentioning

confidence: 88%

“…This new demapping approach considers the distribution of the symbols of the underlying LDM layer when demapping the top-layer signal, which brings a potential gain under certain circumstances at the expense of additional complexity. In addition to [6], the paper evaluates the new demapping concept from a generic point of view, via information theory, and studies the complexity of its implementation at receivers. Furthermore, a new algorithm is proposed, which forwards the a-priori information obtained by the demapping of the top-layer signal to the lowerlayer signal.…”

Section: Introductionmentioning

confidence: 99%

Information-Theoretic Analysis and Performance Evaluation of Optimal Demappers for Multi-Layer Broadcast Systems

Garro

Giménez

Klenner

et al. 2018

IEEE Trans. on Broadcast.

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Multi-layer broadcast systems distribute services across time and frequency domain by means of power-division multiplexing. Successive interference cancellation is required, in general, in order to extract the content of all services. For a lowcomplexity implementation, the receiver can obtain the strongest (top-layer) signal assuming underlying signals to behave like thermal noise. The thermal noise assumption may not be valid under certain conditions and a more accurate characterization of the interference could bring improved performance. This paper analyzes the validity of the noise-like assumption considering the power ratio between signals and the required Carrier-to-Noise ratio (CNR) for error-free reception. The main contribution of the paper is the proposal of a demapping algorithm that exploits the knowledge of the constellation of underlying signals. Generalized Mutual Information, performance evaluation, and complexity analysis are provided with the AWGN-like assumptions and with the proposed alternative in order to assess the potential performance improvements that can be achieved.

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