Efficient signal detector design for OTFS with index modulation

In this paper,efficient signal detectors are designed for Orthogonal Time Frequency Space(OTFS)modulation with Index Modulation(IM)systems.Firstly,the Minimum Mean Squared Error(MMSE)based linear equalizer and its corresponding soft-aided decision are studied for OTFS-IM.To further improve the performance,a Vectorby-Vector-aided Message Passing(VV-MP)detector and its associated soft-decision are proposed,where each IM symbol is considered an entire vector utilized for message calculation and passing.Simulation results are shown that the OTFS-IM system relying on the proposed detectors is capable of providing considerable Bit Error Rate(BER)performance gains over the OTFS and Orthogonal Frequency Division Multiplex(OFDM)with IM systems.

Effects of 1-MCP on proline,polyamine,and nitric oxide metabolism in postharvest peach fruit under chilling stress

Peach(Prunus persica Batsch‘Yuhualu’)fruit are sensitive to chilling injury(CI).Proline,polyamine(PA),and nitric oxide(NO)are important small regulators of various metabolic pathways under chilling stress that mitigate CI.Ethylene is known to promote senescence and CI,while 1-methylcyclopropene(1-MCP)is an antagonist that inhibits the effects of ethylene.However,how1-MCP and ethylene affect proline,PA,and NO levels under chilling stress remains unclear.To address these questions,1-MCP(1μL·L^(−1))and ethylene(1μL·L^(−1))treatments were applied to peach fruit.Fruit were stored at 4°C for 28 d,then moved to 25°C for 3 d immediately after cold storage.Peach fruit exhibited CI symptoms after 7 d of cold storage with enhanced electrolyte leakage and malondialdehyde contents.The 1-MCP treatment significantly(P<0.05)restrained peach CI,and fruit did not exhibit CI symptoms until 14 d of cold storage.Proline and PAs in peach under chilling stress weremostly synthesized from glutamate and arginine,which were catalyzed by1-pyrroline-5-carboxylate synthetase and arginine decarboxylase,respectively.1-MCPtreated fruit exhibited higher proline and PA contents and enhanced chilling tolerance compared to the control,while ethylene-treated fruit had lower proline and PA contents and reduced chilling tolerance.Ethylene-treated fruit,which exhibited more severe CI symptoms compared to the control,had significantly(P<0.05)lower NO contents and NO synthase activities.However,NOmay not be a direct acting factor in 1-MCPinduced chilling tolerance,as 1-MCP-treated fruit had lower NO contents and NO synthase activities compared to the control.In conclusion,proline and PA clearly played direct and important roles in 1-MCP-induced peach chilling tolerance,while NO may not be actively involved.

饲料添加剂在非洲猪瘟防控中的作用

非洲猪瘟是一种烈性传染病,其暴发给全球养猪业带来了巨大的损失。至今尚未研发成功相应的疫苗。文章主要探讨了新型添加剂中草药饲料添加剂、微生态制剂对于猪只非特殊免疫力的调节以及对防控非洲猪瘟所起的作用。

Error Probability Analysis for Ultra-Massive MIMO System and Near-Optimal Signal Detection

In this paper,average bit error probability(ABEP)bound of optimal maximum likelihood(ML)detector is first derived for ultra massive(UM)multiple-input-multiple-output(MIMO)system with generalized amplitude phase modulation(APM),which is confirmed by simulation results.Furthermore,a minimum residual criterion(MRC)based lowcomplexity near-optimal ML detector is proposed for UM-MIMO system.Specifically,we first obtain an initial estimated signal by a conventional detector,i.e.,matched filter(MF),or minimum mean square error(MMSE)and so on.Furthermore,MRC based error correction mechanism(ECM)is proposed to correct the erroneous symbol encountered in the initial result.Simulation results are shown that the performance of the proposed MRC-ECM based detector is capable of approaching theoretical ABEP of ML,despite only imposing a slightly higher complexity than that of the initial detector.

A Unified Bit-to-Symbol Mapping for Generalized Constellation Modulation

Gray mapping is a well-known way to improve the performance of regular constellation modulation,but it is challenging to be applied directly for irregular alternative.To address this issue,in this paper,a unified bit-to-symbol mapping method is designed for generalized constellation modulation(i.e.,regular and irregular shaping).The objective of the proposed approach is to minimize the average bit error probability by reducing the hamming distance(HD)of symbols with larger values of pairwise error probability.Simulation results show that the conventional constellation modulation(i.e.,phase shift keying and quadrature amplitude modulation(QAM)with the proposed mapping rule yield the same performance as that of classical gray mapping.Moreover,the recently developed golden angle modulation(GAM)with the proposed mapping method is capable of providing around1 d B gain over the conventional mapping counterpart and offers comparable performance to QAM with Gray mapping.

Performance Analysis for Orthogonal Time Frequency Space Modulation Systems with Generalized Waveform

Orthogonal time-frequency space(OTFS),which exhibits beneficial advantages in high-mobility scenarios,has been considered as a promising technology in future wireless communication systems.In this paper,a universal model for OTFS systems with generalized waveform has been developed.Furthermore,the average bit error probability(ABEP)upper bounds of the optimal maximum likelihood(ML)detector are first derived for OTFS systems with generalized waveforms.Specifically,for OTFS systems with the ideal waveform,we elicit the ABEP bound by recombining the transmitted signal and the received signal.For OTFS systems with practical waveforms,a universal ABEP upper bound expression is derived using moment-generating function(MGF),which is further extended to MIMO-OTFS systems.Numerical results validate that our theoretical ABEP upper bounds are concur with the simulation performance achieved by ML detectors.

Index modulation aided generalized space-time block coding:A unified MIMO framework

In this paper,Index Modulation(IM)aided Generalized Space-Time Block Coding(GSTBC)is proposed,which intrinsically exploits the benefits of IM concept,diversity gain and spatial multiplexing gain.Specifically,the information bits are partitioned into U groups,with each being modulated by IM symbols(i.e.Spatial Modulation(SM),Quadrature SM(QSM),etc).Next,the structure of GSTBC is invoked for each K IM symbol,and a total ofμ=U/K GSTBC codes are transmitted via T time slots.A Block Expectation Propagation(B-EP)detector is designed for the proposed IM-GSTBC structure.Moreover,the theoretical Average Bit Error Probability(ABEP)is derived for our IM-GSTBC system,which is confirmed by the simulation results and helpful for performance evaluation.Simulation results show that our proposed IM-GSTBC system is capable of striking an efficient trade-off between spatial multiplexing gain,spatial diversity gain as well as implementation cost imposed for both small-scale and large-scale MIMO antenna configurations.

Digital-to-analog converter free architecture for digital reconfigurable intelligent surface

This research investigates the digital-to-analog converter(DAC)free architecture for the digital reconfigurable intelligent surface(RIS)system,where the transmission lines are implemented for reflection coefficient(RC)control to reduce power consumption.In the proposed architecture,the radio frequency(RF)switch based phase shifter is considered.By using a single-pole four-throw(SP4T)switch to simultaneously control the RCs of a group of elements,a 2-bit phase shifter is realized for passive beam steering.A novel modulation scheme is developed to explore the cost effectiveness,which approaches the performance of traditional quadrature amplitude modulation(QAM).Specifically,to overcome the limitation of the phase shift bits,joint frequency-shift and phase-rotation operations are applied to the constellation points.The simulation and experimental results demonstrate that the proposed architecture is capable of providing an ideal transmission performance.Moreover,64-and 256-QAM modulation schemes could be implemented by expanding the elements and phase bits.

Targeting NUF2 suppresses gastric cancer progression through G2/M phase arrest and apoptosis induction

Background:Gastric cancer(GC),a malignant tumor with poor prognosis,is one of the leading causes of cancer-related deaths worldwide;consequently,identifying novel therapeutic targets is crucial for its corresponding treatment.NUF2,a component of the NDC80 kinetochore complex,promotes cancer progression in multiple malignancies.Therefore,this study aimed to explore the potential of NUF2 as a therapeutic target to inhibit GC progression.Methods:Clinical samples were obtained from patients who underwent radical resection of GC at Lanzhou University Second Hospital from 2016 to 2021.Cell count assays,colony formation assays,and cell-derived xenotransplantation(CDX)models were used to determine the effects of NUF2 on GC progression.Flow cytometry was used to detect the effect of NUF2 or quercetin on cell cycle progression and apoptosis.A live-cell time-lapse imaging assay was performed to determine the effect of NUF2 on the regulation of mitotic progression.Transcriptomics was used to investigate the NUF2-associated molecular mechanisms.Virtual docking and microscale thermophoresis were used to identify NUF2 inhibitors.Finally,CDX,organoid,and patient-derived xenograft(PDX)models were used to examine the efficacy of the NUF2 inhibitor in GC.Results:NUF2 expression was significantly increased in GC and was negatively correlated with prognosis.The deletion of NUF2 suppressed GC progression both in vivo and in vitro.NUF2 significantly regulated the mitogen-activated protein kinase(MAPK)pathway,promoted G2/M phase transition,and inhibited apoptosis in GC cells.Additionally,quercetin was identified as a selective NUF2 inhibitor with low toxicity that significantly suppressed tumor growth in GC cells,organoids,CDX,and PDX models.Conclusions:Collectively,NUF2-mediated G2/M phase transition and apoptosis inhibition promoted GC progression;additionally,NUF2 inhibitors exhibited potent anti-GC activity.This study provides a new strategy for targeting NUF2 to suppress GC progression in clinical settings.