558 research outputs found
Low Complexity Decoding for Higher Order Punctured Trellis-Coded Modulation Over Intersymbol Interference Channels
Trellis-coded modulation (TCM) is a power and bandwidth efficient digital
transmission scheme which offers very low structural delay of the data stream.
Classical TCM uses a signal constellation of twice the cardinality compared to
an uncoded transmission with one bit of redundancy per PAM symbol, i.e.,
application of codes with rates when denotes the
cardinality of the signal constellation.
Recently published work allows rate adjustment for TCM by means of puncturing
the convolutional code (CC) on which a TCM scheme is based on.
In this paper it is shown how punctured TCM-signals transmitted over
intersymbol interference (ISI) channels can favorably be decoded. Significant
complexity reductions at only minor performance loss can be achieved by means
of reduced state sequence estimation.Comment: 4 pages, 5 figures, 3 algorithms, accepted and published at 6th
International Symposium on Communications, Control, and Signal Processing
(ISCCSP 2014
Low Complexity Decoding for Punctured Trellis-Coded Modulation Over Intersymbol Interference Channels
Classical trellis-coded modulation (TCM) as introduced by Ungerboeck in
1976/1983 uses a signal constellation of twice the cardinality compared to an
uncoded transmission with one bit of redundancy per PAM symbol, i.e.,
application of codes with rates when denotes the
cardinality of the signal constellation. The original approach therefore only
comprises integer transmission rates, i.e., , additionally, when transmitting over an intersymbol interference
(ISI) channel an optimum decoding scheme would perform equalization and
decoding of the channel code jointly. In this paper, we allow rate adjustment
for TCM by means of puncturing the convolutional code (CC) on which a TCM
scheme is based on. In this case a nontrivial mapping of the output symbols of
the CC to signal points results in a time-variant trellis. We propose an
efficient technique to integrate an ISI-channel into this trellis and show that
the computational complexity can be significantly reduced by means of a reduced
state sequence estimation (RSSE) algorithm for time-variant trellises.Comment: 4 pages, 7 pictured, accepted for 2014 International Zurich Seminar
on Communication
Signatures of correlated magnetic phases in the local two-particle density matrix
Experiments with quantum gas microscopes have started to explore the
antiferromagnetic phase of the two-dimensional Fermi-Hubbard model and effects
of doping with holes away from half filling. In this work we show how direct
measurements of the system averaged two-spin density matrix and its full
counting statistics can be used to identify different correlated magnetic
phases with or without long-range order. We discuss examples of phases which
are potentially realized in the Hubbard model close to half filling, including
antiferrromagnetically ordered insulators and metals, as well as insulating
spin-liquids and metals with topological order. For these candidate states we
predict the doping- and temperature dependence of local correlators, which can
be directly measured in current experiments.Comment: 15 pages, 7 figure
Punctured Trellis-Coded Modulation
In classic trellis-coded modulation (TCM) signal constellations of twice the
cardinality are applied when compared to an uncoded transmission enabling
transmission of one bit of redundancy per PAM-symbol, i.e., rates of
when denotes the cardinality of the signal
constellation. In order to support different rates, multi-dimensional (i.e.,
-dimensional) constellations had been proposed by means of
combining subsequent one- or two-dimensional modulation steps, resulting in
TCM-schemes with bit redundancy per real dimension. In
contrast, in this paper we propose to perform rate adjustment for TCM by means
of puncturing the convolutional code (CC) on which a TCM-scheme is based on. It
is shown, that due to the nontrivial mapping of the output symbols of the CC to
signal points in the case of puncturing, a modification of the corresponding
Viterbi-decoder algorithm and an optimization of the CC and the puncturing
scheme are necessary.Comment: 5 pages, 10 figures, submitted to IEEE International Symposium on
Information Theory 2013 (ISIT
Determinants of microinsurance demand: evidence from a micro life scheme in Indonesia
The objective of this research is to identify and evaluate socio-economic determinants of micro life insurance demand in Indonesia. The study is motivated by the fact that, while microinsurance is considered to facilitate poverty alleviation and economic development in emerging economies, take-up rates remain behind projections. To attract the required private capital needed for the provision of financial access and market development, however, high take-up rates are essential to create a commercially viable business opportunity. This study aims to provide insight in customer characteristics which cause actual microinsurance take-up and, thereby, facilitate more effective product design and distribution to seize the opportunities in microinsurance.
For this study a sample of 208 microfinance customers was collected through personally-administered questionnaires in the urban and semi-urban area of Jakarta, Indonesia. All interviewees were previously offered to participate in a micro life insurance program. About half of the sample decided to participate while the other half abstained from the program. Based on the socio-economic household data gathered in the field study, factors influencing the demand for microinsurance are determined through econometric analysis.
The results of this thesis, based on marginal effects probit regression analysis, support earlier findings regarding the positive influence of education and household wealth on life insurance uptake. In addition, economic capacity measurements deemed more appropriate for low-income households are introduced and corroborate an unambiguous strong positive influence of households' relative economic capacity. Further, positive influence is found for respondents' financial literacy and product understanding as well as client trust attitude and brand recognition. A strong negative life-cycle effect is revealed when taking into account economic self-sufficiency of dependents
Reduced Complexity Super-Trellis Decoding for Convolutionally Encoded Transmission Over ISI-Channels
In this paper we propose a matched encoding (ME) scheme for convolutionally
encoded transmission over intersymbol interference (usually called ISI)
channels. A novel trellis description enables to perform equalization and
decoding jointly, i.e., enables efficient super-trellis decoding. By means of
this matched non-linear trellis description we can significantly reduce the
number of states needed for the receiver-side Viterbi algorithm to perform
maximum-likelihood sequence estimation. Further complexity reduction is
achieved using the concept of reduced-state sequence estimation.Comment: 6 pages, 8 figures, accepted for ICNC'13. (see also: arXiv:1205.7031
Religion und ökologische Nachhaltigkeit: Zwischen grünen Glaubensgemeinschaften und Ökospiritualität
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