Pub Date : 2001-03-20DOI: 10.1109/SPAWC.2001.923846
J. Xavier, V. Barroso
We derive the asymptotic performance analysis of a recently introduced analytical method for blind identification of multiple-input multiple-output (MIMO) convolutive systems excited by inputs with distinct second-order spectra; the spectral diversity in the second-order moments is induced by correlative filters located at the sources. We establish the asymptotic normality of the MIMO channel estimator and obtain a closed-form expression for the mean square error (MSE) of the channel estimates. The theoretical study permits us to investigate the impact of certain key system parameters on the resulting MSE and to obtain guidelines for the optimum design of the correlative filters. Computer simulations are carried out to validate the theoretical expressions.
{"title":"Blind identification of MIMO channels based on correlative coding: performance analysis","authors":"J. Xavier, V. Barroso","doi":"10.1109/SPAWC.2001.923846","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923846","url":null,"abstract":"We derive the asymptotic performance analysis of a recently introduced analytical method for blind identification of multiple-input multiple-output (MIMO) convolutive systems excited by inputs with distinct second-order spectra; the spectral diversity in the second-order moments is induced by correlative filters located at the sources. We establish the asymptotic normality of the MIMO channel estimator and obtain a closed-form expression for the mean square error (MSE) of the channel estimates. The theoretical study permits us to investigate the impact of certain key system parameters on the resulting MSE and to obtain guidelines for the optimum design of the correlative filters. Computer simulations are carried out to validate the theoretical expressions.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122505139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-03-20DOI: 10.1109/SPAWC.2001.923907
Chung-Yao Chang, Shiunn-Jang Chern
A new general linearly constrained recursive least squares (RLS) array beamforming algorithm, based on an inverse QR decomposition, is developed for multiple jammer suppression. It is known the LS weight vector can be computed without back substitution in the inverse QRD-based algorithms and is suitable to be implemented using the systolic array. Also, the problem of the unacceptable numerical performance in limited-precision environments, occurring in the "fast" RLS filtering algorithms, can be avoided. To document the advantage of this new constrained algorithm, performance, in terms of convergence property of the learning curve and the capability of jammer suppression, is investigated. We show that our proposed algorithm outperforms the LCLMS algorithm and the linearly constraint fast LS algorithm (LCFLS) and its robust version (LCRFSL) algorithm.
{"title":"Adaptive linearly constrained inverse QRD-RLS beamformer for multiple jammers suppression","authors":"Chung-Yao Chang, Shiunn-Jang Chern","doi":"10.1109/SPAWC.2001.923907","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923907","url":null,"abstract":"A new general linearly constrained recursive least squares (RLS) array beamforming algorithm, based on an inverse QR decomposition, is developed for multiple jammer suppression. It is known the LS weight vector can be computed without back substitution in the inverse QRD-based algorithms and is suitable to be implemented using the systolic array. Also, the problem of the unacceptable numerical performance in limited-precision environments, occurring in the \"fast\" RLS filtering algorithms, can be avoided. To document the advantage of this new constrained algorithm, performance, in terms of convergence property of the learning curve and the capability of jammer suppression, is investigated. We show that our proposed algorithm outperforms the LCLMS algorithm and the linearly constraint fast LS algorithm (LCFLS) and its robust version (LCRFSL) algorithm.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122066145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-03-20DOI: 10.1109/SPAWC.2001.923848
J. Ayadi, D. Slock
In a multichannel context, the problem of blind estimation of the channel can be parameterized either by the channel impulse response or by the noise-free multivariate prediction error filter and the first vector coefficient of the vector channel. The noise subspace, spanned by a set of vectors that are orthogonal to the signal subspace, can be parameterized according to different linear parameterizations. We begin with the reasons due to which second-order-statistics-based estimation techniques give accurate channel estimates. We focus on the different noise subspace parameterizations in terms of blocking equalizers and classify them. We present linear (in terms of subchannel impulse responses) noise subspace parameterizations and we prove that using a specific parameterization, which is minimal in terms of the number of rows, leads to span the overall noise subspace.
{"title":"On linear channel-based noise subspace parameterizations for blind multichannel identification","authors":"J. Ayadi, D. Slock","doi":"10.1109/SPAWC.2001.923848","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923848","url":null,"abstract":"In a multichannel context, the problem of blind estimation of the channel can be parameterized either by the channel impulse response or by the noise-free multivariate prediction error filter and the first vector coefficient of the vector channel. The noise subspace, spanned by a set of vectors that are orthogonal to the signal subspace, can be parameterized according to different linear parameterizations. We begin with the reasons due to which second-order-statistics-based estimation techniques give accurate channel estimates. We focus on the different noise subspace parameterizations in terms of blocking equalizers and classify them. We present linear (in terms of subchannel impulse responses) noise subspace parameterizations and we prove that using a specific parameterization, which is minimal in terms of the number of rows, leads to span the overall noise subspace.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128826928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-03-20DOI: 10.1109/SPAWC.2001.923887
Shuguang Cui, Z. Luo, Zhi Ding
Signal detection in multiuser CDMA systems is particularly attractive when the desired user signature and some interferer signatures are known and are not completely orthogonal at the receiver. As many multiuser systems must deal with the near-far problem, a weakness common to several known blind multiuser CDMA detectors is that the detection performance is very sensitive to signature waveform mismatch (SWM) which occurs a result of channel distortion. We consider the design of a partially blind multiuser CDMA detector that is robust to the SWM. We present a convex formulation of this problem by using second-order cone programming (SOCP). The resulting SOCP can be solved efficiently using the recently developed interior point methods. Computer simulations indicate that the performance of our new robust multiuser detector is superior to the one that does not utilize the interference information.
{"title":"Robust CDMA signal detection in the presence of user and interference signature mismatch","authors":"Shuguang Cui, Z. Luo, Zhi Ding","doi":"10.1109/SPAWC.2001.923887","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923887","url":null,"abstract":"Signal detection in multiuser CDMA systems is particularly attractive when the desired user signature and some interferer signatures are known and are not completely orthogonal at the receiver. As many multiuser systems must deal with the near-far problem, a weakness common to several known blind multiuser CDMA detectors is that the detection performance is very sensitive to signature waveform mismatch (SWM) which occurs a result of channel distortion. We consider the design of a partially blind multiuser CDMA detector that is robust to the SWM. We present a convex formulation of this problem by using second-order cone programming (SOCP). The resulting SOCP can be solved efficiently using the recently developed interior point methods. Computer simulations indicate that the performance of our new robust multiuser detector is superior to the one that does not utilize the interference information.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126050001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-03-20DOI: 10.1109/SPAWC.2001.923856
T. Yamada, T. Matsumoto, S. Tomisato, U. Trautwein
This paper shows results of link level simulations conducted to evaluate performances of spatial and temporal equalizers (S/T-equalizers) using field measurement data. The spatial and temporal equalizer discussed has a configuration expressed as a cascaded connection of adaptive array antenna and maximum likelihood sequence estimator (MLSE): each of the antenna elements has a fractionally spaced tapped delay line (FTDL), and the MLSE has taps covering a portion of channel delay profile. Bit error rate (BER) performance of the S/T-equalizers, including that in the presence of co-channel Interference (CCI) are presented. Performance sensitivity to symbol timing offset is also investigated. Major conclusions of this paper are that allocating more taps to the spatial domain is more effective than to the time domain when the total number of taps is fixed, and that increasing the FTDL length is effective in reducing performance sensitivity to timing offset.
{"title":"Performance evaluation for FTDL-spatial/MLSE-temporal equalizer using field measurement data","authors":"T. Yamada, T. Matsumoto, S. Tomisato, U. Trautwein","doi":"10.1109/SPAWC.2001.923856","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923856","url":null,"abstract":"This paper shows results of link level simulations conducted to evaluate performances of spatial and temporal equalizers (S/T-equalizers) using field measurement data. The spatial and temporal equalizer discussed has a configuration expressed as a cascaded connection of adaptive array antenna and maximum likelihood sequence estimator (MLSE): each of the antenna elements has a fractionally spaced tapped delay line (FTDL), and the MLSE has taps covering a portion of channel delay profile. Bit error rate (BER) performance of the S/T-equalizers, including that in the presence of co-channel Interference (CCI) are presented. Performance sensitivity to symbol timing offset is also investigated. Major conclusions of this paper are that allocating more taps to the spatial domain is more effective than to the time domain when the total number of taps is fixed, and that increasing the FTDL length is effective in reducing performance sensitivity to timing offset.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126911794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-03-20DOI: 10.1109/SPAWC.2001.923853
Jitendra Tugnait
Blind channel estimation and equalization for SIMO (single-input multiple-output) time-varying channels is considered using only the second-order statistics of the data. The time-varying channel is assumed to be described by a complex exponential basis expansion model (CE-BEM). The linear prediction error method for blind identification of time-invariant channels is extended to time-varying channels represented by a CE-BEM. Sufficient conditions for identifiability are investigated. The cyclostationary nature of the received signal is exploited for consistent estimation of the time-varying correlation function of the data from a single observation record. The focus of the paper is on certain theoretical issues.
{"title":"On blind equalization of SIMO time-varying channels","authors":"Jitendra Tugnait","doi":"10.1109/SPAWC.2001.923853","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923853","url":null,"abstract":"Blind channel estimation and equalization for SIMO (single-input multiple-output) time-varying channels is considered using only the second-order statistics of the data. The time-varying channel is assumed to be described by a complex exponential basis expansion model (CE-BEM). The linear prediction error method for blind identification of time-invariant channels is extended to time-varying channels represented by a CE-BEM. Sufficient conditions for identifiability are investigated. The cyclostationary nature of the received signal is exploited for consistent estimation of the time-varying correlation function of the data from a single observation record. The focus of the paper is on certain theoretical issues.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127872108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-03-20DOI: 10.1109/SPAWC.2001.923901
A. Alexiou
Space-time block coding-based transmit diversity (STTD) has been adopted by 3GPP as the open loop transmit diversity scheme aiming at improving the FDD downlink capacity. Although the assumption of independent channels corresponding to different transmitting antennas is commonly made when assessing theoretically the resulting improvement, in a practical system the actual correlation between antennas is highly dependent on the antenna separation, the angular spread and the multipath environment. A realistic spatio-temporal channel model is employed in order to quantify the impact of these factors on the actual STTD performance and compare it against the ideal case of independent channels.
{"title":"Realistic channel model considerations in UMTS downlink capacity with space-time block coding","authors":"A. Alexiou","doi":"10.1109/SPAWC.2001.923901","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923901","url":null,"abstract":"Space-time block coding-based transmit diversity (STTD) has been adopted by 3GPP as the open loop transmit diversity scheme aiming at improving the FDD downlink capacity. Although the assumption of independent channels corresponding to different transmitting antennas is commonly made when assessing theoretically the resulting improvement, in a practical system the actual correlation between antennas is highly dependent on the antenna separation, the angular spread and the multipath environment. A realistic spatio-temporal channel model is employed in order to quantify the impact of these factors on the actual STTD performance and compare it against the ideal case of independent channels.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114011273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-03-20DOI: 10.1109/SPAWC.2001.923832
F. Nunes, J. Leitao
Differential detection of phase-shift keying signals entails the ability to establish a phase reference based on previous symbol(s). In communications strongly affected by the Doppler effect, like those involving non-geostationary satellites, the carrier phase drift within the symbol interval may be significant; thus, a better strategy than averaging the phase over previous symbols is to continuously estimate it along the corresponding interval. We propose a receiver for M-DPSK signals in channels affected by fast fading and Doppler frequency shift. A bank of stochastic nonlinear filters estimates the carrier phase drift and the fading vector, which are modeled as stochastic processes within the symbol interval; a key algorithm driven by the filters' outputs estimates the carrier offset frequency, which is considered a constant parameter in each estimation interval (corresponding to at least two-symbol intervals). Simulations with 4-DPSK show that the receiver performs much better than conventional differential phase detectors; it exhibits short convergence times, being able to cope with large Doppler frequency shifts.
{"title":"M-DPSK receiver for Doppler-shift mobile communications","authors":"F. Nunes, J. Leitao","doi":"10.1109/SPAWC.2001.923832","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923832","url":null,"abstract":"Differential detection of phase-shift keying signals entails the ability to establish a phase reference based on previous symbol(s). In communications strongly affected by the Doppler effect, like those involving non-geostationary satellites, the carrier phase drift within the symbol interval may be significant; thus, a better strategy than averaging the phase over previous symbols is to continuously estimate it along the corresponding interval. We propose a receiver for M-DPSK signals in channels affected by fast fading and Doppler frequency shift. A bank of stochastic nonlinear filters estimates the carrier phase drift and the fading vector, which are modeled as stochastic processes within the symbol interval; a key algorithm driven by the filters' outputs estimates the carrier offset frequency, which is considered a constant parameter in each estimation interval (corresponding to at least two-symbol intervals). Simulations with 4-DPSK show that the receiver performs much better than conventional differential phase detectors; it exhibits short convergence times, being able to cope with large Doppler frequency shifts.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123974362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-03-20DOI: 10.1109/SPAWC.2001.923828
S. Tantikovit, M. Wang, A. Sheikh
In Tantikovit et al., (2000), we presented a signal model for interpath interference (IPI) in low spreading factor long-code wideband-CDMA (W-CDMA) systems and showed that the impact of IPI can be decomposed into branch correlation and co-channel interference similar to those in an adaptive array system. We consequently derived optimum and suboptimum combining schemes for the RAKE receiver, which provide significant improvement over the conventional maximum-ratio combining. In this paper, we derive the theoretical probability density function (pdf) of the signal-to-interference-plus-noise ratio and outage probability of the optimum combining scheme in a semi-analytical fashion. The obtained analytical results closely agree with simulation results.
在Tantikovit et al.，(2000)中，我们提出了低扩频因子长码宽带cdma (W-CDMA)系统中路径间干扰(IPI)的信号模型，并表明IPI的影响可以分解为分支相关和同信道干扰，类似于自适应阵列系统中的影响。因此，我们推导了RAKE接收机的最优和次优组合方案，它们比传统的最大比组合有了显著的改进。本文以半解析的方式导出了最佳组合方案的信噪比和中断概率的理论概率密度函数(pdf)。所得分析结果与仿真结果吻合较好。
{"title":"On combining schemes for W-CDMA RAKE reception in the presence of interpath interference","authors":"S. Tantikovit, M. Wang, A. Sheikh","doi":"10.1109/SPAWC.2001.923828","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923828","url":null,"abstract":"In Tantikovit et al., (2000), we presented a signal model for interpath interference (IPI) in low spreading factor long-code wideband-CDMA (W-CDMA) systems and showed that the impact of IPI can be decomposed into branch correlation and co-channel interference similar to those in an adaptive array system. We consequently derived optimum and suboptimum combining schemes for the RAKE receiver, which provide significant improvement over the conventional maximum-ratio combining. In this paper, we derive the theoretical probability density function (pdf) of the signal-to-interference-plus-noise ratio and outage probability of the optimum combining scheme in a semi-analytical fashion. The obtained analytical results closely agree with simulation results.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"109 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124084021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-03-20DOI: 10.1109/SPAWC.2001.923930
Chin-Ta Chen, Ching-Tai Chiang, Yuan-Hwang Chen
This letter integrates the Karhunen-Loeve (KL) transform with the overlapped subframe techniques for efficient speaker identification under an additive noise environment. Based on the overlapped subframe partition method, we present an efficient technique to construct an eigenvector matrix and achieve the advantages of the KL transform technique. Computer simulations demonstrate the effectiveness of the proposed technique.
{"title":"Efficient KLT based on overlapped subframes for speaker identification","authors":"Chin-Ta Chen, Ching-Tai Chiang, Yuan-Hwang Chen","doi":"10.1109/SPAWC.2001.923930","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923930","url":null,"abstract":"This letter integrates the Karhunen-Loeve (KL) transform with the overlapped subframe techniques for efficient speaker identification under an additive noise environment. Based on the overlapped subframe partition method, we present an efficient technique to construct an eigenvector matrix and achieve the advantages of the KL transform technique. Computer simulations demonstrate the effectiveness of the proposed technique.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131777640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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