15,707 research outputs found
A Universal Receiver for Uplink NOMA Systems
Given its capability in efficient radio resource sharing, non-orthogonal
multiple access (NOMA) has been identified as a promising technology in 5G to
improve the system capacity, user connectivity, and scheduling latency. A dozen
of uplink NOMA schemes have been proposed recently and this paper considers the
design of a universal receiver suitable for all potential designs of NOMA
schemes. Firstly, a general turbo-like iterative receiver structure is
introduced, under which, a universal expectation propagation algorithm (EPA)
detector with hybrid parallel interference cancellation (PIC) is proposed (EPA
in short). Link-level simulations show that the proposed EPA receiver can
achieve superior block error rate (BLER) performance with implementation
friendly complexity and fast convergence, and is always better than the
traditional codeword level MMSE-PIC receiver for various kinds of NOMA schemes.Comment: This paper has been accepted by IEEE/CIC International Conference on
Communications in China (ICCC 2018). 5 pages, 4 figure
Turbo-like Iterative Multi-user Receiver Design for 5G Non-orthogonal Multiple Access
Non-orthogonal multiple access (NoMA) as an efficient way of radio resource
sharing has been identified as a promising technology in 5G to help improving
system capacity, user connectivity, and service latency in 5G communications.
This paper provides a brief overview of the progress of NoMA transceiver study
in 3GPP, with special focus on the design of turbo-like iterative multi-user
(MU) receivers. There are various types of MU receivers depending on the
combinations of MU detectors and interference cancellation (IC) schemes.
Link-level simulations show that expectation propagation algorithm (EPA) with
hybrid parallel interference cancellation (PIC) is a promising MU receiver,
which can achieve fast convergence and similar performance as message passing
algorithm (MPA) with much lower complexity.Comment: Accepted by IEEE 88th Vehicular Technology Conference (IEEE VTC-2018
Fall), 5 pages, 6 figure
Charge-Density-Wave Transitions of Dirac Fermions Coupled to Phonons
The spontaneous generation of charge-density-wave order in a Dirac fermion
system via the natural mechanism of electron-phonon coupling is studied in the
framework of the Holstein model on the honeycomb lattice. Using two independent
and unbiased quantum Monte Carlo methods, the phase diagram as a function of
temperature and coupling strength is determined. It features a quantum critical
point as well as a line of thermal critical points. Finite-size scaling appears
consistent with fermionic Gross-Neveu-Ising universality for the quantum phase
transition, and bosonic Ising universality for the thermal phase transition.
The critical temperature has a maximum at intermediate couplings. Our findings
motivate experimental efforts to identify or engineer Dirac systems with
sufficiently strong and tunable electron-phonon coupling.Comment: 4+3 pages, 4+2 figure
3-(4-HydroxyÂphenylÂimino)indolin-2-one
In the title compound, C14H10N2O2, the dihedral angle between the indole and benzene rings is 61.63 (4)°. In the crystal structure, centrosymmetrically related molÂecules are linked into dimers by N—H⋯O hydrogen bonds, generating rings of graph-set motif R
2
2(8). The dimers are further connected into a three-dimensional network by O—H⋯O and C—H⋯O hydrogen bonds
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