Optimization of high-order non-uniform QAM constellations

Zoellner, J.; Loghin, Nabil

doi:10.1109/bmsb.2013.6621711

Cited by 67 publications

(35 citation statements)

References 6 publications

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“…13 Taking into account the quadrant symmetry of QAM, this optimization can be simplified to only finding the optimal positive amplitudes of a PAM constellation (i.e., 1D optimization). For a square M -QAM constellation, this leads to have a set of √ M /2 PAM symbols to be optimized.…”

Section: 19mentioning

confidence: 99%

Unified Satellite and Terrestrial ACM Design

Haqiqatnejad

Kayhan

2017

35th AIAA International Communications Satellite Systems Conference

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First step towards integrating satellite and terrestrial standards at the physical layer is to design a unified packet frame structure, and in particular, a unified adaptive coding and modulation (ACM) scheme without substantial loss in either of the systems. In this paper we introduce a methodology to design such a set of modulation and coding (MODCOD) combinations. In the first step, we design a set of base MODCODs for the AWGN channel. Then, for any other given channel model, we build a new set of MODCODs through a suitable transformation of the base MODCODs. We mainly focus on two types of channels: (a) non-linear satellite channels, and (b) AWGN channels with fading. We compare our results with latest digital video broadcasting standards, namely, DVB-T2 and DVB-S2X. Nomenclature

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Section: 19mentioning

confidence: 99%

Unified Satellite and Terrestrial ACM Design

Haqiqatnejad

Kayhan

2017

35th AIAA International Communications Satellite Systems Conference

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“…Note that the gain provided by NUCs becomes almost non-existent at high SNRs, especially when optimizing for fading channels [24]. In this particular case, Signal Space Diversity (SSD) techniques can be used to improve the overall system performance.…”

Section: Preliminariesmentioning

confidence: 99%

“…The algorithm utilized in this thesis does not reach an optimum solution for large numbers of DoF, thus making impossible to design higher-order constellations. The optimization method needs to be improved in order to design 2D-NUCs with 1024 and 4096 symbols, achieving extremely high capacity gains compared to QAM and 1D-NUCs, as shown in [24]. In turn, performance gains provided by these constellations should be thoroughly studied.…”

Section: Constellation and Cr Recommendationmentioning

confidence: 99%

“…Here, the concept of a condensed constellation is presented for the first time. In [24], high-order 1D-and 2D-NUCs are optimized up to 1024 symbols as well, also for AWGN channel. The presented constellations approach the Shannon limit up to 0.036 bit/s/Hz at 29 dB of SNR, corresponding to a short-coming of approximately 0.1 dB.…”

Section: Non-uniform Constellationsmentioning

confidence: 99%

“…The study of these constellations for broadcast transmissions has been explored in several studies. Reference [38] was the first research approaching the concept of 1D-NUCs, and the most important contributions that explain the use of 2D-NUCs are [17], [24] and [43].…”

Section: Non-uniform Constellations Optimizationmentioning

confidence: 99%

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Non-Uniform Constellations for Next-Generation Digital Terrestrial Broadcast Systems

Muela¹

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Nowadays, the digital terrestrial television (DTT) market is characterized by the high capacity needed for high definition TV services, and the limited spectrum available. There is a need for an efficient use of the broadcast spectrum, which requires new technologies to guarantee increased capacities. NonUniform Constellations (NUC) arise as one of the most innovative techniques to approach those requirements. These constellations have been implemented in next-generation broadcast systems such as DVB-NGH (Digital Video Broadcasting -Next Generation Handheld) or ATSC 3.0 (Advanced Television Systems Committee -Third Generation). NUCs reduce the gap between uniform Gray-labelled Quadrature Amplitude Modulation (QAM) constellations and the theoretical unconstrained Shannon limit. With these constellations, symbols are optimized in both in-phase (I) and quadrature (Q) components by means of signal geometrical shaping, considering a certain signal-to-noise ratio (SNR) and channel model.There are two types of NUC, depending on the number of real-valued dimensions considered in the optimization process, i.e. one-dimensional and two dimensional NUCs (1D-NUC and 2D-NUC, respectively). 1D-NUCs maintain the squared shape from QAM, but relaxing the distribution between constellation symbols in a single component, with non-uniform distance between them. These constellations provide better SNR performance than QAM, without any demapping complexity increase. 2D-NUCs also relax the square shape constraint, allowing to optimize the symbol positions in both dimensions, thus achieving higher capacity gains and lower SNR requirements. However, the use of 2D-NUCs implies a higher demapping complexity, since a 2D-demapper is needed, i.e. I and Q components cannot be separated.In this dissertation, NUCs are analyzed from both transmit and receive point of views, using either single-input single-output (SISO) or multiple-input multiple-output (MIMO) antenna configurations. In SISO transmissions, 1D-NUCs and 2D-NUCs are optimized for a wide range of SNRs, several channel models and different constellation orders, using the Nelder-Mead optimization 3 ABSTRACT algorithm. The optimization of rotated 2D-NUCs is also investigated, including the rotation angle as an additional variable in the optimization. Even though the demapping complexity is not increased, the SNR gain of these constellations is not significant. The highest rotation gain is obtained for low-order constellations and high SNRs. However, with multi-RF techniques such as Channel Bonding (CB) or Time-Frequency Slicing (TFS), the SNR gain is drastically increased, since I and Q components are transmitted in different RF channels. In this thesis, multi-RF gains of NUCs with and without rotation are provided for some representative scenarios.At the receiver, two different implementation bottlenecks are explored. First, the demapping complexity of all considered constellations is analyzed. Afterwards, two complexity reduction algorithms for 2D-NUCs are proposed. Both algor...

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New DVB‐S2X constellations for improved performance on the satellite channel

Eroz

Lee

Loghin³

et al. 2015

Satell Commun Network

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Digital Video Broadcasting via satellite second generation has experienced worldwide adoption because of its revolutionary and yet practical physical layer technology and its flexibility. Recently, the standard has been updated with several new features without changing its fundamental structure. This paper provides a high-level discussion on several of the most important additions to the new standard with particular emphasis on some of the new signal constellations.Consequently, the 2 + 4 + 2APSK constellation can often be operated with pilots switched off, resulting in 2.5% overhead reduction. This benefit comes on top of an SNR gain of 0.2dB for standard (non-iterative) demapping and LDPC decoding. Phase noise resilienceThe DVB-S2X User Guidelines [8] detail the phase noise assumptions for the different satellite system components and for various service types, resulting in end-to-end phase noise masks denoted as P1 Figure 3. 64-Ary constellation of DVB-S2X.Figure 4. Constrained capacity comparison of several 64-ary constellations.Daniel Delaruelle has been active in satellite communications since 1985 and joined Newtec Cy, Belgium in 1988, where he took up equipment design, team lead, and staff scientist positions. His research interests include system synchronisation, waveform design, optimal resource scheduling, channel estimation, and distortion/interference countermeasures. He made key contributions to widely deployed standard-based and proprietary satellite transmission technologies and served on the DVB ad hoc workgroups evolving the DVB-DSNG, DVB-RCS, DVB-S2, DVB-S2X, and DVB-CID specifications. He received his Masters degree in Electrical Engineering from the

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Optimization of high-order non-uniform QAM constellations

Cited by 67 publications

References 6 publications

Unified Satellite and Terrestrial ACM Design

Unified Satellite and Terrestrial ACM Design

Non-Uniform Constellations for Next-Generation Digital Terrestrial Broadcast Systems

New DVB‐S2X constellations for improved performance on the satellite channel

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