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| 1 | Source Separation of Diesel Engine Vibration Based on the Empirical Mode Decomposition and Independent Component Analysis显示文摘Vibration signals from diesel engine contain many different components mainly caused by combustion and mechanism operations,several blind source separation techniques are available for decomposing the signal into its components in the case of multichannel measurements,such as independent component analysis(ICA).However,the source separation of vibration signal from single-channel is impossible.In order to study the source separation from single-channel signal for the purpose of source extraction,the combination method of empirical mode decomposition(EMD) and ICA is proposed in diesel engine signal processing.The performance of the described methods of EMD-wavelet and EMD-ICA in vibration signal application is compared,and the results show that EMD-ICA method outperforms the other,and overcomes the drawback of ICA in the case of single-channel measurement.The independent source signal components can be separated and identified effectively from one-channel measurement by EMD-ICA.Hence,EMD-ICA improves the extraction and identification abilities of source signals from diesel engine vibration measurements. | DU Xianfeng LI Zhijun BI Fengrong ZHANG Junhong WANG Xia SHAO Kang | 2012 | Chinese Journal of Mechanical Engineering2012，25，3： | 21 |
| 2 | Stable carbon and hydrogen isotopes of gases from the large tight gas fields in China显示文摘By the end of the year 2010,a total of 15 large tight gas fields have been found in China,located in the Ordos,Sichuan,and Tarim basins.The annual production and total reserves of these fields in 2010 were 222.5×108and 28657×108m3,respectively,accounting for 23.5%and 37.3%,respectively,of the total annual production and reserves of natural gases in China.They took a major part of all natural gas production and reserves in China.According to the analyses of 81 gas samples,the stable carbon and hydrogen isotopic compositions of tight gases in China have following characteristics:(1)Plots of 13C1-13C2-13C3,13C1-C1/C2+3and 13C1-13C2demonstrate the coal-derived origin of tight gases in China;(2)For the primary alkane gases,both carbon and hydrogen isotopic values increase with increasing molecular mass,i.e.,13C1<13C2<13C3<13C4and2H1<2H2<2H3;(3)The isotopic differences of 13C2-13C1,13C3-13C1,2H2-2H1and 2H3-2H1decrease with increasing Ro(%)and C1/C1–4;(4)There are seven causes for the carbon and hydrogen isotopic reversal,however,the carbon and hydrogen isotopic reversal of tight gases in China is caused mainly by multiple stages of gas charge and accumulation. | DAI JinXing NI YunYan HU GuoYi HUANG ShiPeng LIAO FengRong YU Cong GONG DeYu WU Wei | 2014 | Science China Earth Sciences2014，57，1： | 17 |
| 3 | IL-10 Gene Modified Dendritic Cells Inhibit T Helper Type 1-Mediated Alloimmune Responses and Promote Immunological Tolerance in Diabetes显示文摘Dendritic cells (DCs) have the potency to regulate the outcome of autoimmunity through the modulation of immune responses. The induction of antigen specific tolerance is critical for prevention and treatment of allograft rejection. In the present study,we transfected IL-10 gene into DCs and investigated their effect on inhibition of lymphocyte activity in vitro and induction of immune tolerance on islet allograft in mice. An IDDM C57BL/6 mouse model was induced by streptozotocin. The islet cells isolated from the BALB/c mice were transplanted into the kidney capules of the model mice followed by injection of IL-10 modified DCs (mDCs). The results showed that mDCs could significantly inhibit T lymphocyte proliferation mediated by allotype cells and induce its apoptosis,whereas,unmodified DCs (umDCs) could promote the murine lymphocyte proliferation markedly. The injection of mDCs could prolong the survival of allotype islet transplanted IDDM mice. The average plasma glucose (PG) level in mDCs treated mice returned to normal within 3 days and lasted for about 2 weeks. The rejection response in control mice occurred for 5 days after transplantation. The level of IFN-γ was lower while IL-4 was higher in mDCs treated mice than that in umDCs treated mice,which indicated that Th1/Th2 deviation occurred. Our studies suggest that IL-10 gene modified DCs can induce the immune tolerance to islet graft and prolong survival of the recipients by the inhibiting of T cell proliferation in allotype mice. | Huifen Zhu Wenhong Qiu Ping Lei Wei Zhou Xue Wen Fengrong He Li Li Hong Dai Guanxin Shen Feili Gong | 2008 | Cellular & Molecular Immunology2008，5，1： | 14 |
| 4 | Aero-engine Blade Fatigue Analysis Based on Nonlinear Continuum Damage Model Using Neural Networks显示文摘Fatigue life and reliability of aero-engine blade are always of important significance to flight safety.The establishment of damage model is one of the key factors in blade fatigue research.Conventional linear Miner's sum method is not suitable for aero-engine because of its low accuracy.A back propagation neutral network(BPNN) based on the combination of Levenberg-Marquardt(LM) and finite element method(FEM) is used to describe process of nonlinear damage accumulation behavior in material and predict fatigue life of the blade.Fatigue tests of standard specimen made from TC4 are carried out to obtain material fatigue parameters and S-N curve.A nonlinear continuum damage model(CDM),based on the BPNN with one hidden layer and ten neurons,is built to investigate the nonlinear damage accumulation behavior,in which the results from the tests are used as training set.Comparing with linear models and previous nonlinear models,BPNN has the lowest calculation error in full load range.It has significant accuracy when the load is below 500 MPa.Especially,when the load is 350 MPa,the calculation error of the BPNN is only 0.4%.The accurate model of the blade is built by using 3D coordinate measurement technology.The loading cycle in fatigue analysis is defined from takeoff to cruise in 10 min,and the load history is obtained from finite element analysis(FEA).Then the fatigue life of the compressor blade is predicted by using the BPNN model.The final fatigue life of the aero-engine blade is 6.55 104 cycles(10 916 h) based on the BPNN model,which is effective for the virtual design of aero-engine blade. | LIN Jiewei ZHANG Junhong ZHANG Guichang NI Guangjian BI Fengrong | 2012 | Chinese Journal of Mechanical Engineering2012，25，2： | 13 |
| 5 | Interferon-α salvage treatment is effective for patients with acute leukemia/myelodysplastic syndrome with unsatisfactory response to minimal residual disease-directed donor lymphocyte infusion after allogeneic hematopoietic stem cell transplantation显示文摘The efficacy of salvage interferon-α(IFN-α) treatment was investigated in patients with unsatisfactory response to minimal residual disease (MRD)-directed donor lymphocyte infusion (DLI)(n=24). Patients who did not become MRD-negative at 1 month after DLI were those with unsatisfactory response and were eligible to receive salvage IFN-α treatment within 3 months of DLI. Recombinant human IFN-α-2b injections were subcutaneously administered 2–3 times a week for 6 months. Nine (37.5%), 6 (25.0%), and 3 (12.5%) patients became MRD-negative at 1, 2, and>2 months after the salvage IFN-α treatment, respectively. Two-year cumulative incidences of relapse and non-relapse mortality were 35.9% and 8.3%, respectively. Two-year probabilities of event-free survival, disease-free survival, and overall survival were 51.6%, 54.3%, and 68.0%, respectively. Outcomes of patients subjected to salvage IFN-α treatment after DLI were significantly better than those with persistent MRD without IFN-α treatment. Moreover, clinical outcomes were comparable between the salvage DLI and IFN-α treatment groups. Thus, salvage IFN-α treatment may help improve the outcome of patients with unsatisfactory responses to MRD-directed DLI and could be a potential salvage treatment for these patients after allogeneic hematopoietic stem cell transplantation. | Xiaodong Mo Xiaohui Zhang Lanping Xu Yu Wang Chenhua Yan Huan Chen Yuhong Chen Wei Han Fengrong Wang Jingzhi Wang Kaiyan Liu Xiaojun Huang | 2019 | Frontiers of Medicine2019，13，2： | 6 |
| 6 | Analysis of Thermoelastohydrodynamic Performance of Journal Misaligned Engine Main Bearings显示文摘To understand the engine main bearings' working condition is important in order to improve the performance of engine. However, thermal effects and thermal effect deformations of engine main bearings are rarely considered simultaneously in most studies. A typical finite element model is selected and the effect of thermoelastohydrodynamic(TEHD) reaction on engine main bearings is investigated. The calculated method of main bearing's thermal hydrodynamic reaction and journal misalignment effect is finite difference method, and its deformation reaction is calculated by using finite element method. The oil film pressure is solved numerically with Reynolds boundary conditions when various bearing characteristics are calculated. The whole model considers a temperature-pressure-viscosity relationship for the lubricant, surface roughness effect, and also an angular misalignment between the journal and the bearing. Numerical simulations of operation of a typical I6 diesel engine main bearing is conducted and importance of several contributing factors in mixed lubrication is discussed. The performance characteristics of journal misaligned main bearings under elastohydrodynamic(EHD) and TEHD loads of an I6 diesel engine are received, and then the journal center orbit movement, minimum oil film thickness and maximum oil film pressure of main bearings are estimated over a wide range of engine operation. The model is verified through the comparison with other present models. The TEHD performance of engine main bearings with various effects under the influences of journal misalignment is revealed, this is helpful to understand EHD and TEHD effect of misaligned engine main bearings. | BI Fengrong SHAO Kang LIU Changwen WANG Xia ZHANG Jian | 2015 | Chinese Journal of Mechanical Engineering2015，28，3： | 6 |
| 7 | Studies on wind environment around high buildings in urban areas显示文摘High buildings or architectural complex in urban areas remarkably distort the urban surface wind fields. As the air flow approaches,local strong wind may appear around the buildings. The strong wind makes the pedestrians on sidewalks, entrances and terrace very uncomfortable and causes the pedestrian level wind environment problem. In this studies, hot-wire wind measurement, wind scouring in wind tunnel and numerical computation were carried out to evaluate the wind environment of tall buildings in the prevailing flow conditions in Beijing areas. The results obtained by three techniques were compared and mutually verified. The conclusions drawn from three approaches agree with each other. Also the advantages and limitations of each method were analyzed. It is suggested that the combination of different techniques may produce better assessment of wind environment around high buildings. | LIU Huizhi, JIANG Yujun, LIANG Bin, ZHU Fengrong, ZHANG Boyin & SANG Jianguo LAPC, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China Department of Atmospheric Sciences, School of Physics, Peking University, Beijing 1000871, China State Key Laboratory of Turbulence and Complex System, Peking University, Beijing 1000871, China | 2005 | Science China Earth Sciences2005，48，z2： | 5 |
| 8 | Reduced β2-GPI is associated with increased platelet aggregation and activation in patients with prolonged isolated thrombocytopenia after allo-HSCT显示文摘We aimed to measure platelet function and its relationship with β2-GPI in prolonged isolated thrombocytopenia(PT) after allogeneic hematopoietic stem cell transplantation(allo-HSCT).Fifty-six patients with PT and 60 allo-HSCT recipients without PT(non-PT controls) were enrolled.Platelet aggregation and activation,β2-GPI and anti-β2-GPI antibody levels,vWF antigen,and vWF activity were analyzed.The effect of β2-GPI on platelet aggregation was also measured ex vivo.Results showed that ADP-induced platelet aggregation significantly increased(39%±7.5% vs.23%±8.5%,P=0.032),and the platelet expression of both CD62 p(33.6%±11.6% vs.8.5%±3.5%,P<0.001) and PAC-1(42.4%±7.6% vs.6.8%±2.2%,P<0.001) was significantly higher in patients with PT than in those without PT.Significantly lower β2-GPI levels(164.2±12 μg m L^-1 vs.234.2±16 μg mL^-1,P<0.001),higher anti-β2-GPI IgG levels(1.78±0.46 U mL^-1 vs.0.94±0.39 U mL^-1,P<0.001),and increased vWF activity(133.06%±30.50% vs.102.17%±25.90%,P<0.001) were observed in patients with PT than in those without PT.Both ADPinduced platelet aggregation(n=116,r^2=-0.5042,P<0.001) and vWF activity(n=116,r^2=-0.2872,P<0.001) were negatively correlated with β2-GPI levels.In summary,our data suggested that platelet aggregation and activation were significantly higher in patients with PT than in those without PT,which might be associated with reduced β2-GPI levels.The reduced β2-GPI levels might be due to the existence of anti-β2-GPI IgG. | Haixia Fu Jingzhong Zhao Lanping Xu Kaiyan Liu Yu Wang Huan Chen Wei Han Jingzhi Wang Fengrong Wang Xiaojun Huang Xiaohui Zhang | 2019 | Science China(Life Sciences)2019，62，7： | 4 |
| 9 | Reliability analysis of aero-engine blades considering nonlinear strength degeneration显示文摘To comprehensively consider the effects of strength degeneration and failure correlation, an improved stress-strength interference (SSI) model is proposed to analyze the reliability of aeroengine blades with the fatigue failure mode. Two types of TC4 alloy experiments are conducted for the study on the damage accumulation law. All the parameters in the nonlinear damage model are obtained by the tension-compression fatigue tests, and the accuracy of the nonlinear damage model is verified by the damage tests. The strength degeneration model is put forward on the basis of the Chaboche nonlinear damage theory and the Griffith fracture criterion, and determined by measuring the fatigue toughness during the tests. From the comparison of two kinds of degeneration models based on the Miner's linear law and the nonlinear damage model respectively, the nonlinear model has a significant advantage on prediction accuracy especially in the later period of life. A time-dependent SSI reliability model is established. By computing the stress distribution using the finite element (FE) technique, the reliability of a single blade during the whole service life is obtained. Considering the failure correlation of components, a modified reliability model of aero-engine blades with common cause failure (CCF) is presented. It shows a closer and more reasonable process with the actual working condition. The improved reliability model is illustrated to be applied to aero-engine blades well, and the approach purposed in this paper is suitable for any actual machinery component of aero-engine rotor systems. | Lin Jiewei Zhang Junhong Yang Shuo Bi Fengrong | 2013 | Chinese Journal of Aeronautics2013，26，3： | 4 |
| 10 | Psychoacoustic Study on Contribution of Fan Noise to Engine Noise显示文摘There are more researches on engine fan noise control focusing on reducing fan noise level through optimizing fan structure,and a lot of research achievements have been obtained.However,researches on the effect of fan noise to engine noise quality are lacking.The influences of the effects of fan structure optimization on the engine noise quality are unclear.Thus,there will be a decline in fan noise level,but the deterioration of engine noise quality.Aiming at the above problems,in consideration of fan structure design and engine noise quality,an innovative method to analyze the contribution of fan noise to engine noise quality using psychoacoustic theory is proposed.The noises of diesel engine installing different cooling fans are measured by using the acoustic pressure method.The experiment results are regarded as analysis samples.The model of sensory pleasantness is used to analyze the sound quality of a diesel engine with different cooling fans.Results show that after installing 10-blade fan in medium diameter the sensory pleasantness at each test point is increased,and the increase is 13.53% on average,which indicate the improvement of the engine noise quality.In order to verify the psychoacoustical analysis,the subjective assessment is carried out.The test result shows the noise quality of engine installed10-blade fan in medium diameter is most superior.1/3 octave frequency spectrum analysis is used to study the reason of the improvement of engine noise quality.It is found that after installing proper cooling fan the sound pressure level below 400 Hz are obviously increased,the frequency assignment and spectral envelope are more reasonable and a proper cooling fan can optimize the spectrum structure of the engine noise.The psychoacoustic study is applied in the contribution of fan noise to engine noise,and the idea of engine sound quality improvement through the structure optimization is proposed. | ZHANG Junhong LIU Hai BI Fengrong NI Guangjian ZHANG Guichang LIN Jiewei YU Hanzhengnan | 2012 | Chinese Journal of Mechanical Engineering2012，25，4： | 3 |
| 11 | Evaluation of Land Reclamation and Implications of Ecological Restoration for Agro-pastoral Ecotone: Case Study of Horqin Left Back Banner in China显示文摘The agro-pastoral ecotone has been recognized as the main distribution area of reserved land resource for cultivation. Accordingly, clarifying this assumption, as well as concerting land reclamation and ecological restoration, is important to ensure food security and environmental improvement in the agro-pastoral ecotone. We selected Horqin Left Back Banner(HLBB) as the subject of our case study. The landscape ecological security pattern of this area was determined using the minimum cumulative resistance model. Over-cultivation, quantity of reserved land resource for cultivation, and changes in landscape indexes before and after land use adjustment were then analyzed. Over-cultivation is a serious problem in the agro-pastoral ecotone. Reserved land resource for cultivation is less than that considered previously, and the area of reserved land resource for cultivation in HLBB only accounts for 11.50% of total uncultivated land. With regard to changes in landscape indexes, the adjusted land use pattern is effective for anti-desertification. The compensation standard for abandoned cultivated land should be improved and the comprehensive results of ‘Grain for Green' should be evaluated to further implement ecological restoration in the agro-pastoral ecotone. | ZHOU Jian ZHANG Fengrong XU Yan GAO Yang XIE Zhen | 2017 | Chinese Geographical Science2017，27，5： | 3 |
| 12 | Origin and source of CO_2 in natural gas from the eastern Sichuan Basin显示文摘The CO2 contents of natural gas from the eastern Sichuan Basin were mainly less than 2%,and they were generally large when the H2S contents were over 5%.The natural gas in the eastern Sichuan Basin showed high δ13C1 values uncorrelated with H2S contents,and the oil-associated gas generally displayed carbon isotopic reversal between methane and ethane,whereas the coal-derived gas samples displayed positive series.The δ13C values of CO2 in the natural gas could be divided into two types,one with low values(-24‰--12‰)and the other with high values(-8‰-4‰).The natural gas had low R/Ra values and broad CO2/3He values distinct from the mantle-derived gas,and the CO2 was typical of crustal origin.Natural gas with high δ13CCO2 values is distributed in the north region of the eastern Sichuan Basin,and CO2 in H2S-poor and H2S-free reservoirs was mainly derived from the thermal decomposition of carbonate rocks under Permian magmatism and high heat flow,whereas CO2 in the gas reservoirs with high TSR extent was derived mainly from the dedolomitization of carbonate reservoirs under acidic formation water,and the CO2 of TSR origin generally entered into the secondary calcite.The CO2 in natural gas in the south-central region of the eastern Sichuan Basin,which had been rarely affected by the Emeishan mantle plume,displayed low δ13C values and was of organic origin.Though the natural gas in Wolonghe gas field had experienced TSR,the low reaction extent and weak acidity of formation water could hardly have resulted in the dedolomitization,and therefore CO2 in the natural gas was mainly of TSR origin with low δ13C values. | WU XiaoQi DAI JinXing LIAO FengRong HUANG ShiPeng | 2013 | Science China Earth Sciences2013，56，8： | 3 |
| 13 | Risk factors for chronic graft-versus-host disease after anti-thymocyte globulin-based haploidentical hematopoietic stem cell transplantation in acute myeloid leukemia显示文摘Chronic graft-versus-host disease(cGVHD)is a major complication following unmanipulated haploidentical hematopoietic stem cell transplantation(haplo-HSCT).We aimed to identify the risk factors for cGVHD in patients who underwent anti-thymocyte globulin-based haplo-HSCT for acute myeloid leukemia(n=280).The diagnosis of cGVHD was in accordance with the National Institutes of Health consensus criteria.A total of 169 patients suffered from cGVHD.The patients who had 3 loci mismatched had a higher 8-year incidence of cGVHD(total,66.0%vs.53.7%,P=0.031;moderate to severe,42.4%vs.30.1%,P=0.036)than the patients who had 1 to 2 loci mismatched.The patients who had maternal donors had a higher 8-year incidence of moderate to severe cGVHD(49.2%vs.32.9%,P=0.024)compared with the patients who had other donors.The patients who had grades III to IV acute GVHD(aGVHD)had higher 8-year incidence of cGVHD(total,88.0%vs.50.4%,P<0.001;moderate to severe,68.0%vs.27.0%,P<0.001)compared with the patients without aGVHD.In multivariate analysis,grades III to IV aGVHD was the only independent risk factor for cGVHD.Thus,further interventions should be considered in patients with severe aGVHD to prevent cGVHD. | Meng Lv Xiaohui Zhang Lanping Xu Yu Wang Chenhua Yan Huan Chen Yuhong Chen Wei Han Fengrong Wang Jingzhi Wang Kaiyan Liu Xiaojun Huang Xiaodong Mo | 2019 | Frontiers of Medicine2019，13，6： | 2 |
| 14 | Minimal residual disease-directed immunotherapy for high-risk myelodysplastic syndrome after allogeneic hematopoietic stem cell transplantation显示文摘The efficacy of minimal residual disease (MRD)-directed immunotherapy,including interferon-α (IFN-α) treatment and chemotherapy plus granulocyte colony-stimulating factor-primed donor leukocyte infusion (chemo-DLI),was investigated in patients with high-risk myelodysplastic syndrome (MDS) who were MRD-positive after allogeneic hematopoietic stem cell transplantation (allo-HSCT).High-risk MDS patients who received non-T-cell-depleted allo-HSCT at the Peking University Institute of Hematology and were MRD-positive after ailo-HSCT were studied (n =47).The MRD-positive status was considered if leukemia-associated aberrant immune phenotypes or Wilms' tumor gene 1 expression is present in a single bone marrow sample.The cumulative incidence of the relapse and non-relapse mortality 2 years after immunotherapy were 14.5% and 21.4% (P=0.377)and 9.1% and 0.0% (P=0.985) for patients in the IFN-α and chemo-DLI groups,respectively.The probability of disease-free and overall survival 2 years after immunotherapy were 76.4% and 78.6% (P =0.891) and 84.3% and 84.6% (P=0.972) for patients in the IFN-α and chemo-DLI groups,respectively.Persistent MRD after immunotherapy was associated with poor survival.Thus,the MRD-directed immunotherapy was effective for patients with high-risk MDS who were MRD-positive after alIo-HSCT,and the efficacy was comparable between chemo-DLI and IFN-α treatment. | Xiaodong Mo Xiaohui Zhang Lanping Xu Yu Wang Chenhua Yan Huan Chen Yuhong Chen Wei Han Fengrong Wang Jingzhi Wang Kaiyan Liu Xiaojun Huang | 2019 | Frontiers of Medicine2019，13，3： | 2 |
| 15 | Fault diagnosis of diesel engine based on adaptive wavelet packets and EEMD-fractal dimension显示文摘 | WANG Xia LIU Changwen BI Fengrong | 2013 | Mechanical Systems and Signal Processing2013，41，12： | 1 |
| 16 | Suitability evaluation of fruit trees in Beijing western mountain areas based on DEM and GIS显示文摘 | Li Hong Sun Danfeng Zhang Fengrong | 2002 | Transactions of CSAE2002，18，51： | 1 |
| 17 | The grain potential of cultivated lands in mainland China in 2004 显示文摘 | ZHANG JINKE ZHANG FENGRONG ZAI-ING DI | 2009 | Land Use Policy2009，26，1： | 1 |
| 18 | Structural and thermoelectric characterizations of high pressure sintered nanocrystalline Bi 2 Te 3 bulks显示文摘 | Fengrong Yu Bo Xu Jianjun Zhang Dongli Yu Julong He Zhongyuan Liu Yongjun Tian | 2012 | Materials Research Bulletin2012，，6： | 1 |
| 19 | Semi-chemical interaction between graphitic carbon nitride and Pt for boosting photocatalytic hydrogen evolution显示文摘Owing to the exorbitant overpotential and serious carrier recombination of graphitic carbon nitride(gC_(3)N_(4)),noble metal(NM)is usually served as the H_(2)evolution co-catalyst.Although the NM(such as Pt)nanoparticles can reduce the H_(2)evolution overpotential,the weak van der Waals interaction between Pt and g-C_(3)N_(4)makes against the charge transfer.Herein,the solvothermal method is developed to achieve semi-chemical interaction between Pt and g-C_(3)N_(4)nanotube(Pt-CNNT)for fast charge transfer.Moreover,the generated in-plane homojunction of CNNT can accelerate charge separation and restrain recombination.Meanwhile,the metallic Pt is an excellent H_(2)evolution co-catalyst.Photo/electrochemical tests verify that the semi-chemical interaction can improve photogenerated charge separation and transferability of CNNT.As a result,the photocatalytic H_(2)evolution turnover frequency(TOF)of Pt-CNNT under visible light irradiation reaches up to 918 h^(-1),which is one of the highest in the g-C_(3)N_(4)-based photocatalysts.This work provides a new idea to improve the charge transfer for efficient photocatalytic H_(2)evolution. | Ziai Zhong Lisha Chen Longshuai Zhang Feiyao Wu Xunheng Jiang Haiyan Liu Fengrong Lv Haiyang Xie Fanqi Meng Lingling Zheng Jianping Zou | 2022 | Chinese Chemical Letters2022，33，6： | 1 |
| 20 | A Novel Inter-Carrier Interference Cancellation Scheme in Highly Mobile Environments显示文摘In the current multi-carrier communications,Orthogonal Frequency Division Multiplexing(OFDM)is widely considered as a leading technology.For mobile applications,however,the orthogonality between subcarriers is deteriorated by Doppler frequency shift,which will introduce serious subcarrier phase rotation in the received signals and degrade the system performance.Thus,a method of differential grouping weighted symmetry data-conjugate(DWSCC)have been previously presented to obtain a better inter-carrier interference(ICI)suppressing effect and Bit Error Rate(BER)performance with no loss of spectral efficiency.In this paper,a novel scheme applying a completely different method of subcarrier interactive mapping is put forward.By mapping two different symbols which are both conjugated or multiplied by a complex weighting factor onto a pair of symmetric subcarriers,the presented scheme can greatly reduce the influence of subcarriers phase rotation caused by Doppler frequency shift in highly mobile environments.Analysis and simulation results indicate that comparing with the DWSCC method,our formulated scheme can not only maintain the spectrum utilization with no loss,but also have the advantages of an improvement on reduction effect and BER performance as well as a lower computational complexity in highly mobile environments. | Tianming Ma Xiaoxiao Jiang Yongqi Wang Fengrong Li | 2020 | China Communications2020，17，12： | 1 |
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