Abstract-In this paper, Tomlinson-Harashima precoding for multiple-input/multiple-output systems including multiple-antenna and multi-user systems is studied. It is shown that nonlinear preequalization offers significant advantages over linear preequalization which increases average transmit power. Moreover, it outperforms decision-feedback equalization at the receiver side which is applicable if joint processing at the receiver side is possible, and which suffers from error propagation. A number of aspects of practical importance are studied. Loading, i.e., the optimum distribution of transmit power and rate is discussed in detail. It is shown that the capacity of the underlying MIMO channel can be utilized asymptotically by means of non-linear precoding.
A new loading algorithm for discrete multitone transmission is proposed. Thereby rate is not distributed according to channel capacity, but rate and transmit power are assigned to maximize the signal-to-noise ratio in each carrier. Because closed form expressions can be derived the algorithm is of very low complexity, even lower than the loading algorithm recently proposed by Chow et al. [ 3 ] . Nevertheless achievable performance is higher or at least the same. Results for a typical high rate transmission over twisted pair lines are presented.
-We consider the lattice-reduction-aided detection scheme for 2×2 channels recently proposed by Yao and Wornell . Using an equivalent real-valued substitute MIMO channel model their lattice reduction algorithm can be replaced by the well-known LLL algorithm, which enables the application to MIMO systems with arbitrary numbers of dimensions. We show how lattice reduction can also be favourably applied in systems that use precoding and give simulation results that underline the usefulness of this approach.
I. INTRODUCTIONIn a recent publication by Yao and Wornell  a novel scheme for improved detection of signals transmitted over multiple-input/multiple-output (MIMO) systems was presented. The astonishing property of this scheme is that it results in error rate curves that parallel those for maximumlikelihood (ML) detection (with some penalty in power efficiency), at only a fraction of the complexity.In the present work we show how their approach fits in the general (maximum-likelihood) lattice decoding framework of  and extend the work of , which presented an optimum algorithm for 2 × 2 complex MIMO systems based on Gaussian reduction , to higher-dimensional settings. The key point is the application of the (sub-optimum) basis reduction algorithm by A. K. Lenstra, H. W. Lenstra and L. Lovász ("LLL algorithm",). Note that this algorithm has also been used in connection with efficient near-ML decoding of differential space-time codes in . Furthermore, we will show how this approach can be applied in precoding/preequalization schemes.
Background-Hypertensive target organ damage, especially cardiac hypertrophy with heart failure and arrhythmia, is a major source of morbidity and mortality. Angiotensin II, a major mediator of hypertension and cardiac damage, has proinflammatory properties. Inflammation and activation of the immune system play a pivotal role in pathogenesis of hypertensive target organ damage. However, the role of immunosuppressive CD4
Milk is a major food of global economic importance, and its consumption is regarded as a classic example of gene-culture evolution. Humans have exploited animal milk as a food resource for at least 8500 years, but the origins, spread, and scale of dairying remain poorly understood. Indirect lines of evidence, such as lipid isotopic ratios of pottery residues, faunal mortality profiles, and lactase persistence allele frequencies, provide a partial picture of this process; however, in order to understand how, where, and when humans consumed milk products, it is necessary to link evidence of consumption directly to individuals and their dairy livestock. Here we report the first direct evidence of milk consumption, the whey protein β-lactoglobulin (BLG), preserved in human dental calculus from the Bronze Age (ca. 3000 BCE) to the present day. Using protein tandem mass spectrometry, we demonstrate that BLG is a species-specific biomarker of dairy consumption, and we identify individuals consuming cattle, sheep, and goat milk products in the archaeological record. We then apply this method to human dental calculus from Greenland's medieval Norse colonies, and report a decline of this biomarker leading up to the abandonment of the Norse Greenland colonies in the 15th century CE.
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