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Abstract Background Aicardi-Goutières syndrome (AGS) is a rare hereditary early-onset encephalopathy characterized by upregulation of the type I interferon pathway, poorly responsive to conventional immunosuppression. Case presentation We describe a 7-year-old Chinese boy who developed symptoms at the age of 6 months. He presented with a chilblain-like rash, leukopenia, neutropenia, elevated liver enzymesgrowth retardation, microcephaly, elevated acute phase reactants, intracranial calcification and leukodystrophy. At the age of 3 years old, whole-exome sequencing confirmed a de novo heterozygous gain-of-function mutation, c.1016 C > A (p.Ala339Asp), in the IFIH1 gene, and he was diagnosed with AGS7. He was treated with ruxolitinib accompanied by steroids and thalidomide for about four years. The rash, hematological manifestations, and the liver function were all improved, but the erythrocyte sedimentation rate remained consistently elevated until the addition of tocilizumab, a monoclonal antibody against interleukin 6. Conclusions Ruxolitinib was not successful in suppressing the inflammatory process, and tocilizumab produced highly encouraging results in reducing the inflammatory reaction of AGS. The study makes a significant contribution to the literature because we may found a potential alternative therapeutic option for AGS.

High peak-to-average power ratio (PAPR) is one of the common drawbacks of multicarrier signals at the transmitter. In this paper, we investigate the PAPR reduction of spectral efficient multicarrier faster-than-Nyquist (MFTN) signals, where the PAPR problem has still not been seriously considered yet in current literatures. Specifically, the low complexity deliberate clipping scheme is exploited in MFTN signaling system. In order to evaluate the practical system performance, we consider a memoryless high power amplifier PAPR-efficiency model, and the auxiliary channel model under low complexity symbol-by-symbol receiver is also derived. Moreover, the achievable spectral efficiency (ASE) which can be viewed as the low bound for any modulation and coding schemes is taken as a figure of merit throughout this paper. By jointly optimizing the time-frequency spacing and clipping ratio to maximization the ASE under the given shaping pulse and modulation format, we show that the ASE of clipping-based MFTN substantially outperforms conventional Nyquist signaling schemes.

Multicarrier faster-than-Nyquist (MFTN) is a spectral efficient transmission scheme for future communication systems. However, as one of the most important drawbacks of multicarrier transmission systems, the peak-to-average power ratio (PAPR) of MFTN signals is still not clear yet. In this paper, we investigate the PAPR of MFTN signals for nonlinear satellite communication systems. First of all, the PAPR distribution of MFTN signals under various practical situations is evaluated, and we show that the PAPR of MFTN signals is closely related to the number of subcarriers, the shaping pulse, and the time–frequency packing factors. Moreover, different from conventional Nyquist multicarrier signals, certain time–frequency packing in MFTN will however, improve the PAPR performance. Then, the PAPR of MFTN signals under the given spectral efficiency is considered. By jointly optimizing the time–frequency spacing to minimize the PAPR, we show that the MFTN combined with low-order modulation could be more energy efficient than the corresponding Nyquist high-order modulation signals. Finally, we investigate the PAPR reduction for MFTN signals. Specifically, a selective mapping-based alternative-signal scheme, which mainly intended for the conventional Nyquist multicarrier signals, is extended to the MFTN signaling system. It is shown that the PAPR reduction performance of the considered scheme is robust to the time–frequency packing, and even approaches the conventional orthogonal frequency-division multiplexing system. Our numerical results validate that besides the high spectral efficiency, the MFTN may be also an energy efficient transmission scheme for next-generation satellite communication systems.

Multicarrier faster-than-Nyquist (MFTN) signaling is a spectral efficient modulation scheme for future communication systems. In MFTN signaling, the intersymbol interference (ISI) and intercarrier interference (ICI) are introduced intentionally by the time interval packing between adjacent symbols and frequency spacing packing between adjacent subcarriers. It is known that for multicarrier transmission over ISI and ICI channel, conventional rectangular lattice is not the optimal lattice structure. In this paper, the optimal hexagonal lattice-based MFTN signaling scheme is proposed. By appropriate staggering for conventional rectangular lattice, it is shown that the minimum Euclidean distance (or 2-DMazo limit) performance can be improved than conventional rectangular lattice-based MFTN signaling scheme. Moreover, a simple symbol-by-symbol receiver coupled with successive soft interference cancellation has been employed to recover the MFTN signals. Numerical results demonstrate that the hexagonal MFTN owns better bit error rate performance than conventional rectangular MFTN signaling scheme.

Multicarrier faster-than-Nyquist (MFTN) signaling is a spectral efficient transmission scheme for future communication systems. Similar as general multicarrier signals, the high peak-to-average power ratio (PAPR) is also one of the main drawbacks of MFTN signals. Unfortunately, the PAPR problem in MFTN signaling system has rarely been considered in the literatures. In this paper, we investigate the PAPR reduction for MFTN signals. First, we derive an inverse fast Fourier transform (IFFT)-based implementation of the MFTN transmitter. Based on which, a novel partial transmit sequence (PTS) scheme is proposed for the PAPR reduction of MFTN signals. The proposed PTS scheme relies on a two-stage optimization of the phase weighting factors for the parallel IFFT blocks as well as the phase weighting factors for the information symbols before the summation operation. It is shown that the proposed scheme substantially outperforms the direct employment of conventional Nyquist multicarrier transmission systems-based PTS scheme and also robust to the overlap-add operation introduced by pulse shaping.

Faster-than-Nyquist (FTN) signalling, as a bandwidth-efficient modulation format, attracts many researchers' attention. However, the symbol rates of FTN signal are increasing when the packing ratios decreases. Moreover, the FTN signal with small packing ratios requires a high-rate analogue-to-digital converter. Since the bandwidth of FTN signal remains the same, the samples taken at Nyquist sampling rate do not suffer information loss. However, the variable packing ratios induce extra memory-consumption when the FTN signal is sampled at Nyquist sampling rate. To reduce the sampling rate and the memory-consumption, a new receiver of FTN signal with oversampling is proposed. Simulation results show that the receiver can perform close to the convolution code line. At the same time, the sampling rate and the memory-consumption can be reduced by adjusting the oversampling factors according to the packing ratios. [ABSTRACT FROM AUTHOR]

A simple nonlinear companding transform which makes full use of the statistical characteristics of the original multi-carrier signals and combining them with the simplest clipping theory is proposed to reduce the peak-to-average power ratio (PAPR) of multi-carrier systems. By making a simple truncation to the Rayleigh-distributed original signals, the proposed scheme not only has low implementation complexity but also outperforms conventional companding schemes. [ABSTRACT FROM AUTHOR]