Precoded Cluster Hopping in Multi-Beam High Throughput Satellite Systems

in Proceedings-IEEE Global Communications Conference (IEEE Globecom), Hawaii, 2019 (2019)

Beam-Hopping (BH) and precoding are two trending technologies for the satellite community. While BH enables flexibility to adapt the offered capacity to the heterogeneous demand, precoding aims at ... [more ▼]

Beam-Hopping (BH) and precoding are two trending technologies for the satellite community. While BH enables flexibility to adapt the offered capacity to the heterogeneous demand, precoding aims at boosting the spectral efficiency. In this paper, we consider a high throughput satellite (HTS) system that employs BH in conjunction with precoding. In particular, we propose the concept of Cluster-Hopping (CH) that seamlessly combines the BH and precoding paradigms and utilizes their individual competencies. The cluster is defined as a set of adjacent beams that are simultaneously illuminated. In addition, we propose an efficient time-space illumination pattern design, where we determine the set of clusters that can be illuminated simultaneously at each hopping event along with the illumination duration. We model the CH time-space illumination pattern design as an integer programming problem which can be efficiently solved. Supporting results based on numerical simulations are provided which validate the effectiveness of the proposed CH concept and time-space illumination pattern design. [less ▲]

Precoding Design and User Selection for Multibeam Satellite Channels

in 16th IEEE International Workshop on Signal Processing Advances in Wireless Communications, SPAWC 2015 (2015, June 28)

Precoding for the downlink of a multibeam satellite system has been recently shown, under ideal conditions, to be promising technique towards employing aggressive frequency reuse gainfully. However, time ... [more ▼]

Precoding for the downlink of a multibeam satellite system has been recently shown, under ideal conditions, to be promising technique towards employing aggressive frequency reuse gainfully. However, time varying phase uncertainties imposed by the components and the channel, combined with delayed feedback perturbs the channel state information at the transmitter (CSIT). In this paper, we consider a power constrained robust formulation of the downlink precoding problem to counter the phase uncertainties. In particular it considers imposing conditions on the average signal to interference plus noise ratio (SINR), to deal with imperfect CSIT. In addition to the robust formulation, the primacy of user selection is highlighted and a new approach exploiting the satellite system design is proposed. Performance of the derived robust precoder in conjunction with the proposed location based user selection is then evaluated and the gains are tabulated. [less ▲]

Precoding in Multibeam Satellite Communications: Present and Future Challenges

in IEEE Wireless Communications Letters (2016), 23(6), 88-95

Precommitment in Competing Vertical Chains

in Journal of Economic Surveys (1998), 12(4), 333-59

The design of distribution channels is an important marketing decision since a revision implies costly reorganization. Hence, it makes sense to study strategic motives of alternative distribution devices ... [more ▼]

The design of distribution channels is an important marketing decision since a revision implies costly reorganization. Hence, it makes sense to study strategic motives of alternative distribution devices. A precommitment is a strategic move that affects the other players' expectations on how oneself will behave and thus induces them to choose in one's own favor (Schelling, 1960). How these tactics can be used by firms to favorably influence competition between vertical chains is the topic of the literature reviewed in this survey. Copyright 1998 by Blackwell Publishers Ltd [less ▲]

Predgovor

in Goldberg, Jeffrey (Ed.) Obama: Vanjskopolitička doktrina (2016)

Predgovor hrvatskom izdanju

in Nye, Joseph S. (Ed.) Budućnost moći (2012)

Predicting Air Compressor Failures with Echo State Networks

in Third European Conference of the Prognostics and Health Management Society 2016, Bilbao, Spain, 5-8 July, 2016 (2016)

Predicting biogas production rate with Black/Grey-Box-Models based on artificially produced datasets

Poster (2015)

Predicting first-grade mathematics achievement: the contributions of domain-general cognitive abilities, nonverbal number sense, and early number competence

in Frontiers in Psychology [=FPSYG] (2014), 5

Early number competence, grounded in number-specific and domain-general abilities, is supposed to lay the foundation for later math achievement. Few longitudinal studies tested a comprehensive model for ... [more ▼]

Early number competence, grounded in number-specific and domain-general abilities, is supposed to lay the foundation for later math achievement. Few longitudinal studies tested a comprehensive model for early math development. Using structural equation modeling and mediation analyses, we studied the influence of kindergarteners’ basic cognitive abilities (i.e., nonverbal number sense, working memory, fluid intelligence, and receptive vocabulary) and their early number competence (i.e., symbolic number skills) on first grade math achievement (arithmetic, shape and space, and number line estimation) assessed one year later. Latent regression models revealed that nonverbal number sense and working memory are central building blocks for developing early number competence in kindergarten and that early number competence is key for first grade math achievement. Fluid intelligence significantly predicted arithmetic and number line estimation while receptive vocabulary significantly predicted shape and space after controlling for early number competence. In sum we suggest that early math achievement draws on different constellations of number-specific and domain-general mechanisms. [less ▲]

Predicting Functional Effects of Missense Variants in Voltage-Gated Sodium and Calcium Channels

E-print/Working paper (2019)

Malfunctions of voltage-gated sodium and calcium channels (SCN and CACNA1 genes) have been associated with severe neurologic, psychiatric, cardiac and other diseases. Altered channel activity is ... [more ▼]

Malfunctions of voltage-gated sodium and calcium channels (SCN and CACNA1 genes) have been associated with severe neurologic, psychiatric, cardiac and other diseases. Altered channel activity is frequently grouped into gain or loss of ion channel function (GOF or LOF, respectively) which is not only corresponding to clinical disease manifestations, but also to differences in drug response. Experimental studies of channel function are therefore important, but laborious and usually focus only on a few variants at a time. Based on known gene-disease-mechanisms, we here infer LOF (518 variants) and GOF (309 variants) of likely pathogenic variants from disease phenotypes of variant carriers. We show regional clustering of inferred GOF and LOF variants, respectively, across the alignment of the entire gene family, suggesting shared pathomechanisms in the SCN/CACNA1 genes. By training a machine learning model on sequence- and structure-based features we predict LOF- or GOF- associated disease phenotypes (ROC = 0.85) of likely pathogenic missense variants. We then successfully validate the GOF versus LOF prediction on 87 functionally tested variants in SCN1/2/8A and CACNA1I (ROC = 0.73) and in exome-wide data from > 100.000 cases and controls. Ultimately, functional prediction of missense variants in clinically relevant genes will facilitate precision medicine in clinical practice. [less ▲]