8,135 research outputs found
A Mixed-ADC Receiver Architecture for Massive MIMO Systems
Motivated by the demand for energy-efficient communication solutions in the
next generation cellular network, a mixed-ADC receiver architecture for massive
multiple input multiple output (MIMO) systems is proposed, which differs from
previous works in that herein one-bit analog-to-digital converters (ADCs)
partially replace the conventionally assumed high-resolution ADCs. The
information-theoretic tool of generalized mutual information (GMI) is exploited
to analyze the achievable data rates of the proposed system architecture and an
array of analytical results of engineering interest are obtained. For
deterministic single input multiple output (SIMO) channels, a closed-form
expression of the GMI is derived, based on which the linear combiner is
optimized. Then, the asymptotic behaviors of the GMI in both low and high SNR
regimes are explored, and the analytical results suggest a plausible ADC
assignment scheme. Finally, the analytical framework is applied to the
multi-user access scenario, and the corresponding numerical results demonstrate
that the mixed system architecture with a relatively small number of
high-resolution ADCs is able to achieve a large fraction of the channel
capacity without output quantization.Comment: 5 pages, 5 figures, to appear in IEEE Information Theory Workshop
(ITW2015
Mirror nuclei constraint in mass formula
The macroscopic-microscopic mass formula is further improved by considering
mirror nuclei constraint. The rms deviation with respect to 2149 measured
nuclear masses is reduced to 0.441 MeV. The shell corrections, the deformations
of nuclei, the neutron and proton drip lines, and the shell gaps are also
investigated to test the model. The rms deviation of alpha-decay energies of 46
super-heavy nuclei is reduced to 0.263 MeV. The central position of the
super-heavy island could lie around N=176~178 and Z=116~120 according to the
shell corrections of nuclei.Comment: 15 pages, 7 figures, 3 tables; version to appear in Phys. Rev.
IR-improved Soft-wall AdS/QCD Model for Baryons
We construct an infrared-improved soft-wall AdS/QCD model for baryons by
considering the infrared-modified 5D conformal mass and Yukawa coupling of the
bulk baryon field. The model is also built by taking into account the
parity-doublet pattern for the excited baryons. When taking the bulk vacuum
structure of the meson field to be the one obtained consistently in the
infrared-improved soft-wall AdS/QCD model for mesons, we arrive at a consistent
prediction for the baryon mass spectrum in even and odd parity. The prediction
shows a remarkable agreement with the experimental data. We also perform a
calculation for the meson-nucleon coupling constant and obtain a
consistent result in comparison with the experimental data and many other
models.Comment: 12 pages, 4 tables, 1 figure, to be published in PL
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