In this paper, we consider symbol-level precoding (SLP) in channel-coded multiuser multi-input single-output (MISO) systems. It is observed that the received SLP signals do not always follow Gaussian ...distribution, rendering the conventional soft demodulation with the Gaussian assumption unsuitable for the coded SLP systems. It, therefore, calls for novel soft demodulator designs for non-Gaussian distributed SLP signals with accurate log-likelihood ratio (LLR) calculation. To this end, we first investigate the non-Gaussian characteristics of both phase-shift keying (PSK) and quadrature amplitude modulation (QAM) received signals with existing SLP schemes and categorize the signals into two distinct types. The first type exhibits an approximate-Gaussian distribution with the outliers extending along the constructive interference region (CIR). In contrast, the second type follows some distribution that significantly deviates from the Gaussian distribution. To obtain accurate LLR, we propose the modified Gaussian soft demodulator and Gaussian mixture model (GMM)-expectation-maximization (EM) soft demodulators to deal with two types of signals respectively. Subsequently, to further reduce the computational complexity and pilot overhead, we put forward a novel neural network named pilot feature extraction network (PFEN) to replace the EM algorithm, leveraging the transformer mechanism in deep learning. Simulation results show that the proposed soft demodulators dramatically improve the throughput of existing SLPs for both PSK and QAM transmission in coded systems.
Latin mottos today Gabrelyan Polina Ivanovna; Danilina Natalia Ivanovna
Studia humanitatis (Moscow),
07/2022, Letnik:
2
Journal Article
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The article analyses the use of Latin mottos in the modern world. The main areas of Latin mottos application are medicine, education, in English-speaking countries also territorial symbols and ...sports. For Russian linguistic culture, the revival of the tradition of Latin mottos in personal symbolism has been established. In the field of medicine mottoes-quotations are predominate; in sports specially composed phrases translated into Latin are mainly used; about a third of the mottoes in territorial and personal symbols are quotations. The main values declared in the mottos are providentialism (territorial symbolism in English-speaking countries), diligence and the will to win (sport), an active life position and self-development (personal symbolism in modern Russian culture).
Symbolic religious establishment (SRE), that is, the noncoercive recognition of religion by the state, has become the object of a growing debate in political philosophy. Although SRE is purely ...symbolic, some have argued that it can be wrong because of the message of political inequality that it sends. The indeterminacy of this expressive argument makes its application problematic, however. The objective of this article is to improve the applicability of the expressivist argument by providing clear guidelines of evaluation of SRE. I develop a three‐step test that helps distinguish permissible from impermissible cases of SRE: religious symbols that are divisive, political, and not appropriately justified are impermissible because of their exclusionary message. One important upshot of the argument is that the appeal to the value of heritage does not provide a plausible justification for the introduction of new religious symbols, and therefore that such neo‐establishment is always impermissible.
Mass-produced of tin-lead alloys and cheap to make and purchase, medieval badges were brooch-like objects displaying familiar images. Circulating widely throughout Europe in the High and late Middle ...Ages, badges were usually small, around four-by-four centimeters, though examples as tiny as two centimeters and a few as large as ten centimeters have been found. About 75 percent of surviving badges are closely associated with specific charismatic or holy sites, and when sewn or pinned onto clothing or a hat, they would have marked their wearers as having successfully completed a pilgrimage. Many others, however, were artifacts of secular life; some were political devices—a swan, a stag, a rose—that would have denoted membership in a civic organization or an elite family, and others—a garland, a pair of clasped hands, a crowned heart—that would have been tokens of love or friendship. A good number are enigmatic and even obscene. The popularity of badges seems to have grown steadily from the last decades of the twelfth century before waning at the very end of the fifteenth century. Some 20, 000 badges survive today, though historians estimate that as many as two million were produced in the fourteenth and fifteenth centuries alone. Archaeologists and hobbyists alike continue to make new finds, often along muddy riverbanks in northern Europe.Interdisciplinary in approach, and sumptuously illustrated with more than 115 color and black-and-white images, Medieval Badges introduces badges in all their variety and uses. Ann Marie Rasmussen considers all medieval badges, whether they originated in religious or secular contexts, and highlights the different ways badges could confer meaning and identity on their wearers. Drawing on evidence from England, France, the Low Countries, Germany, and Scandinavia, this book provides information about the manufacture, preservation, and scholarly study of these artifacts. From chapters exploring badges and pilgrimage, to the complexities of the political use of badges, to the ways the visual meaning-making strategies of badges were especially well-suited to the unique features of medieval cities, this book offers an expansive introduction of these medieval objects for a wide readership.
A new design called spatial media-based modulation with multi-dimensional spatial constellation (SMBM-SC), which develops multiple index domains such as the channel index (CI), antenna index (AI) and ...key index for improving the spectral efficiency (SE), is proposed to construct the α-dimensional (αD) complex spatial symbols to be transmitted over the specified channel states on the active antennas whose each with nrf mirrors. Specifically, with the control of α Switches, the α-D complex spatial symbol is generated by the α-D signal symbol. Then, with the aid of the specified AI vector with the AI bits, one Switch Controller feeds α components of the generated spatial symbol into α active antennas. Another Switch Controller feeds the CI information into α CI Vector Selectors and then modulate α components on the specified channel states with the CI bits to be transmitted, respectively. In addition, in order to further improve the SE, (α+1)-D spatial symbol is designed for exploiting the component permutation index by combining two types of signal symbols. The SE, the detection complexity and the average bit error probability (BEP) are analyzed. Simulation results demonstrate that the SMBM-SC enhance the reliability of communications as compared with the existing MBM schemes.
We investigate the internal structure and density profiles of haloes of mass 10...-10... M... in the Evolution and Assembly of Galaxies and their Environment (EAGLE) simulations. These follow the ...formation of galaxies in a ... cold dark matter Universe and include a treatment of the baryon physics thought to be relevant. The EAGLE simulations reproduce the observed present-day galaxy stellar mass function, as well as many other properties of the galaxy population as a function of time. We find significant differences between the masses of haloes in the EAGLE simulations and in simulations that follow only the dark matter component. Nevertheless, haloes are well described by the Navarro-Frenk-White density profile at radii larger than ~5 per cent of the virial radius but, closer to the centre, the presence of stars can produce cuspier profiles. Central enhancements in the total mass profile are most important in haloes of mass 10...-10... M..., where the stellar fraction peaks. Over the radial range where they are well resolved, the resulting galaxy rotation curves are in very good agreement with observational data for galaxies with stellar mass M* < 5 x 10... M... We present an empirical fitting function that describes the total mass profiles and show that its parameters are strongly correlated with halo mass. (ProQuest: ... denotes formulae/symbols omitted.)
In this work we consider the list-decodability and list-recoverability of arbitrary q -ary codes, for all integer values of q ⩾ 2. A code is called ( p , L ) q -list-decodable if every radius pn ...Hamming ball contains less than L codewords; ( p , ℓ, L ) q -recoverability is a generalization where we place radius pn Hamming balls on every point of a combinatorial rectangle with side length ℓ and again stipulate that there be less than L codewords. Our main contribution is to precisely calculate the maximum value of p for which there exist infinite families of positive rate ( p , ℓ, L ) q -list-recoverable codes, the quantity we call the zero-rate threshold . Denoting this value by p *, we in fact show that codes correcting a p * + ε fraction of errors must have size O ε (1), i.e., independent of n . Such a result is typically referred to as a "Plotkin bound." To complement this, a standard random code with expurgation construction shows that there exist positive rate codes correcting a p * − ε fraction of errors. We also follow a classical proof template (typically attributed to Elias and Bassalygo) to derive from the zero-rate threshold other tradeoffs between rate and decoding radius for list-decoding and list-recovery. Technically, proving the Plotkin bound boils down to demon-strating the Schur convexity of a certain function defined on the q -simplex as well as the convexity of a univariate function derived from it. We remark that an earlier argument claimed similar results for q -ary list-decoding; however, we point out that this earlier proof is flawed.
Orthogonal time frequency space (OTFS) is a promising alternative to orthogonal frequency-division multiplexing (OFDM) for high-mobility communications. We propose a novel multiple-input ...multiple-output (MIMO) integrated sensing and communication (ISAC) system based on OTFS modulation. We begin by deriving new sensing and communication signal models for the proposed MIMO-OTFS ISAC system that explicitly capture inter-symbol interference (ISI) and inter-carrier interference (ICI) effects. We then develop a generalized likelihood ratio test (GLRT) based multi-target detection and delay-Doppler-angle estimation algorithm for MIMO-OTFS radar sensing that can simultaneously mitigate and exploit ISI/ICI effects, to prevent target masking and surpass standard unambiguous detection limits in range/velocity. Moreover, considering two operational modes (discovery/track), we propose an adaptive MIMO-OTFS ISAC transmission strategy. For the discovery mode, we introduce the concept of delay-Doppler (DD) multiplexing, enabling omnidirectional probing of the environment and large virtual array at the OTFS radar receiver. For the track mode, we pursue a directional transmission approach and design an OTFS ISAC optimization algorithm in spatial and DD domains, seeking the optimal trade-off between radar signal-to-noise ratio (SNR) and achievable rate. Simulation results verify the effectiveness of the proposed sensing algorithm and reveal valuable insights into OTFS ISAC trade-offs under varying communication channel characteristics.
This paper investigates the robust design of symbol-level precoding (SLP) for multiuser multiple-input multiple-output (MIMO) downlink transmission with imperfect channel state information (CSI) ...caused by channel aging. By utilizing the a posteriori channel model based on the widely adopted jointly correlated channel model, the imperfect CSI is modeled as the statistical CSI incorporating the channel mean and channel variance information with spatial correlation. With the signal model in the presence of channel aging, we formulate the signal-to-noise-plus-interference ratio (SINR) balancing and minimum mean square error (MMSE) problems for robust SLP design. The former targets to maximize the minimum SINR across users, while the latter minimizes the mean square error between the received signal and the target constellation point. When it comes to massive MIMO scenarios, the increment in the number of antennas poses a computational complexity challenge, limiting the deployment of SLP schemes. To address such a challenge, we simplify the objective function of the SINR balancing problem and further derive a closed-form SLP scheme. Besides, by approximating the matrix involved in the computation, we modify the proposed algorithm and develop an MMSE-based SLP scheme with lower computation complexity. Simulation results confirm the superiority of the proposed schemes over the state-of-the-art SLP schemes.
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