Pub Date : 2008-07-06DOI: 10.1109/SPAWC.2008.4641654
J. Cortez, M. Bazdresch, D. Torres, R. Parra-Michel
Hybrid MIMO communication systems combine spatial multiplexing with diversity gain to achieve both high spectral efficiency and link reliability. We present a novel generalized hybrid scheme that allows the use of any number of spatial multiplexing layers (V-BLAST) and any number of quasi-orthogonal layers (ABBA).We also present a low-complexity, ordered, successive interference cancellation receiver based on sorted QR decomposition. The receiver detects each symbol in the same manner, regardless of whether it was spatially or diversity coded, simplifying the receiverpsilas formulation. We show that this novel scheme outperforms other recent hybrid schemes in terms of bit error rate, even when there is precoding at the transmitter. We also show our proposal has lower complexity, achieved by exploiting the structure of the linear dispersion matrices.
{"title":"Generalized ABBA-V-BLAST hybrid space-time code for wireless communications","authors":"J. Cortez, M. Bazdresch, D. Torres, R. Parra-Michel","doi":"10.1109/SPAWC.2008.4641654","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641654","url":null,"abstract":"Hybrid MIMO communication systems combine spatial multiplexing with diversity gain to achieve both high spectral efficiency and link reliability. We present a novel generalized hybrid scheme that allows the use of any number of spatial multiplexing layers (V-BLAST) and any number of quasi-orthogonal layers (ABBA).We also present a low-complexity, ordered, successive interference cancellation receiver based on sorted QR decomposition. The receiver detects each symbol in the same manner, regardless of whether it was spatially or diversity coded, simplifying the receiverpsilas formulation. We show that this novel scheme outperforms other recent hybrid schemes in terms of bit error rate, even when there is precoding at the transmitter. We also show our proposal has lower complexity, achieved by exploiting the structure of the linear dispersion matrices.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"45 Suppl 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123307935","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641636
N. Vučić, H. Boche
We study the problem of joint transmit and receive filters optimization in a frequency selective, multiple-input multiple-output setup. The information about the channel at the transmitter is imperfect and belongs to a specified uncertainty set, defined by bounding the norm of the error transfer function. The framework for a robust optimization of the system, with mean-square-error (MSE) as the performance measure, is derived. Robustness is defined in the worst-case sense, and a broad range of MSE-optimization problems is supported. The algorithms are constructed in an iterative manner, where each iteration consists of two efficiently solvable semidefinite programs. The proofs of the convergence are provided, as well. Numerical examples show significant performance gains in comparison to the system which performs the optimization of the precoder only.
{"title":"Robust transceiver optimization for frequency selective MIMO channels","authors":"N. Vučić, H. Boche","doi":"10.1109/SPAWC.2008.4641636","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641636","url":null,"abstract":"We study the problem of joint transmit and receive filters optimization in a frequency selective, multiple-input multiple-output setup. The information about the channel at the transmitter is imperfect and belongs to a specified uncertainty set, defined by bounding the norm of the error transfer function. The framework for a robust optimization of the system, with mean-square-error (MSE) as the performance measure, is derived. Robustness is defined in the worst-case sense, and a broad range of MSE-optimization problems is supported. The algorithms are constructed in an iterative manner, where each iteration consists of two efficiently solvable semidefinite programs. The proofs of the convergence are provided, as well. Numerical examples show significant performance gains in comparison to the system which performs the optimization of the precoder only.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126614773","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641622
D. Le Ruyet, H. Khanfir, B. Ozbek
In MISO multiuser downlink wireless communication systems with precoding at the transmission, the capacity depends on the channel state information at the transmitter. Since the feedback data rate increases with the number of users in the cell it is important to perform a selection of the users at the receiver. In this paper, we evaluate the performance of different user selection algorithms at the receiver side through the noisy uplink channel. We evaluate the effect of the noisy channel on the classical norm criterion and on a criterion based on the orthogonality between the user channels. Without cooperation between the users, we only allow users that are semi-orthogonal to feedback their channel information as analog and quantized information to the base station through the noisy uplink channel. We propose an algorithm to reduce the noise effect on the analog feedback for semi-orthogonal user selection algorithm. We show that the semi-orthogonal criterion with quantized feedback gives better performance compared to the norm criterion for perfect and noisy uplink channels.
{"title":"Performance of semi-orthogonal user selection for multiuser MISO systems","authors":"D. Le Ruyet, H. Khanfir, B. Ozbek","doi":"10.1109/SPAWC.2008.4641622","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641622","url":null,"abstract":"In MISO multiuser downlink wireless communication systems with precoding at the transmission, the capacity depends on the channel state information at the transmitter. Since the feedback data rate increases with the number of users in the cell it is important to perform a selection of the users at the receiver. In this paper, we evaluate the performance of different user selection algorithms at the receiver side through the noisy uplink channel. We evaluate the effect of the noisy channel on the classical norm criterion and on a criterion based on the orthogonality between the user channels. Without cooperation between the users, we only allow users that are semi-orthogonal to feedback their channel information as analog and quantized information to the base station through the noisy uplink channel. We propose an algorithm to reduce the noise effect on the analog feedback for semi-orthogonal user selection algorithm. We show that the semi-orthogonal criterion with quantized feedback gives better performance compared to the norm criterion for perfect and noisy uplink channels.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129728248","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641657
Ericsson Research IStockholm, S. Grant, E. Larsson, Feng Zhu
In this contribution we study the impact of transmitter and receiver impairments on the throughput for MIMO and 64 QAM transmissions in an evolved HSDPA system. A simple additive white Gaussian noise model is used to model impairments in the transmitter and receiver chain. The investigation is performed through computer simulations both on link and system level. It is found that the impact from transmitter and receiver distortions is rather small for MIMO with 16 QAM while the impact when 64 QAM is used is more pronounced.
{"title":"Effect of transmitter and receiver impairments on the performance of MIMO in HSDPA","authors":"Ericsson Research IStockholm, S. Grant, E. Larsson, Feng Zhu","doi":"10.1109/SPAWC.2008.4641657","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641657","url":null,"abstract":"In this contribution we study the impact of transmitter and receiver impairments on the throughput for MIMO and 64 QAM transmissions in an evolved HSDPA system. A simple additive white Gaussian noise model is used to model impairments in the transmitter and receiver chain. The investigation is performed through computer simulations both on link and system level. It is found that the impact from transmitter and receiver distortions is rather small for MIMO with 16 QAM while the impact when 64 QAM is used is more pronounced.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128327841","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641678
D. Guel, J. Palicot, J. Bellanger
The distribution of the peak-to-average power ratio (PAPR) for geometric method of PAPR reduction in orthogonal frequency-division multiplexing (OFDM) signals is evaluated in order to analyse the influence of the carrier frequency of adding signal on the PAPR reduction. Assuming that the baseband OFDM signal is characterized as a band-limited complex Gaussian process, we first recall the principle of the geometric approach for PAPR reduction, and we further develop an asymptotic distribution of the PAPR for the method of PAPR reduction.
{"title":"Frequency based asymptotic distribution of the PAPR for geometric adding signal approach in OFDM signals context","authors":"D. Guel, J. Palicot, J. Bellanger","doi":"10.1109/SPAWC.2008.4641678","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641678","url":null,"abstract":"The distribution of the peak-to-average power ratio (PAPR) for geometric method of PAPR reduction in orthogonal frequency-division multiplexing (OFDM) signals is evaluated in order to analyse the influence of the carrier frequency of adding signal on the PAPR reduction. Assuming that the baseband OFDM signal is characterized as a band-limited complex Gaussian process, we first recall the principle of the geometric approach for PAPR reduction, and we further develop an asymptotic distribution of the PAPR for the method of PAPR reduction.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128784278","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641595
R. de Lacerda, L. Cottatellucci, A. Hayar, M. Debbah
Channel Division Multiple Access (ChDMA) is a promising multiple access scheme for Ultra-Wide Band (UWB) systems based on the use of the Channel Impulse Responses (CIR) as user signatures. In this work, we modeled the UWB-CIR as linear combinations of continuous impulses of finite duration randomly delayed. Two different channels are considered: the first, very simplistic, generates multipaths that are uniformly distributed over the time; the second model, which introduces correlation between the delay and the energy of the paths, is built based on the channel power profile. The capacity is investigated assuming no Channel State Information (CSI) at the transmitters and perfect CSI at the receiver. As results, we derive the asymptotic capacity of the ChDMA scheme when the number of users and the number of frequency dimensions (which is proportional to the bandwidth) go to infinity with constant ratio. As a consequence, we observe that the asymptotic spectral efficiency depends only on the system load, the power delay profile, the noise variance and the pulse signal. The results are validated in certain conditions and compared with known results on CDMA systems.
{"title":"Asymptotic analysis of Channel Division Multiple Access schemes for ultra-wideband systems","authors":"R. de Lacerda, L. Cottatellucci, A. Hayar, M. Debbah","doi":"10.1109/SPAWC.2008.4641595","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641595","url":null,"abstract":"Channel Division Multiple Access (ChDMA) is a promising multiple access scheme for Ultra-Wide Band (UWB) systems based on the use of the Channel Impulse Responses (CIR) as user signatures. In this work, we modeled the UWB-CIR as linear combinations of continuous impulses of finite duration randomly delayed. Two different channels are considered: the first, very simplistic, generates multipaths that are uniformly distributed over the time; the second model, which introduces correlation between the delay and the energy of the paths, is built based on the channel power profile. The capacity is investigated assuming no Channel State Information (CSI) at the transmitters and perfect CSI at the receiver. As results, we derive the asymptotic capacity of the ChDMA scheme when the number of users and the number of frequency dimensions (which is proportional to the bandwidth) go to infinity with constant ratio. As a consequence, we observe that the asymptotic spectral efficiency depends only on the system load, the power delay profile, the noise variance and the pulse signal. The results are validated in certain conditions and compared with known results on CDMA systems.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130461536","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641668
N. Ksairi, P. Bianchi, P. Ciblat, W. Hachem
In this paper we investigate the issue of power control and subcarrier assignment in an OFDMA downlink system impaired by multicell interference. As done in Wimax, we assume that a certain part of the available bandwidth is likely to be reused by different base stations (and is thus subject to multicell interference) and that an other part of the bandwidth is used by one base station only (and is thus ldquoprotectedrdquo from multicell interference). Questions are: (i) how many subcarriers should be assigned to a given user in the interference bandwidth, and how many in the protected bandwidth ? (ii) What power should be allocated to a given user in each of these bands ? (iii) What is the optimal frequency reuse factor ?
{"title":"Optimal reuse factor and resource allocation for downlink OFDMA with multicell interference","authors":"N. Ksairi, P. Bianchi, P. Ciblat, W. Hachem","doi":"10.1109/SPAWC.2008.4641668","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641668","url":null,"abstract":"In this paper we investigate the issue of power control and subcarrier assignment in an OFDMA downlink system impaired by multicell interference. As done in Wimax, we assume that a certain part of the available bandwidth is likely to be reused by different base stations (and is thus subject to multicell interference) and that an other part of the bandwidth is used by one base station only (and is thus ldquoprotectedrdquo from multicell interference). Questions are: (i) how many subcarriers should be assigned to a given user in the interference bandwidth, and how many in the protected bandwidth ? (ii) What power should be allocated to a given user in each of these bands ? (iii) What is the optimal frequency reuse factor ?","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132669959","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641590
R. de Francisco, C. Simon, D. Slock, G. Leus
The design of channel quantization codebooks for correlated broadcast channels with limited feedback is addressed. A design criterion that effectively exploits the cell statistics is proposed, based on minimizing the average sum-rate distortion in a system with joint linear beamforming and multiuser scheduling. The proposed average distortion function is optimized by generating a set of quantization codebooks through random trials, keeping the codebook that yields the lowest distortion. Comparisons with limited feedback approaches relying on random codebooks are provided, highlighting the importance of matching the codebook design to the cell statistics. Numerical results show a performance gain in scenarios with non-uniform user distributions. Further, we propose a scheme that exploits the limited channel knowledge at the base station to reduce the computational complexity of determining the beamforming vectors and of finding the optimal user set.
{"title":"Beamforming for correlated broadcast channels with quantized channel state information","authors":"R. de Francisco, C. Simon, D. Slock, G. Leus","doi":"10.1109/SPAWC.2008.4641590","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641590","url":null,"abstract":"The design of channel quantization codebooks for correlated broadcast channels with limited feedback is addressed. A design criterion that effectively exploits the cell statistics is proposed, based on minimizing the average sum-rate distortion in a system with joint linear beamforming and multiuser scheduling. The proposed average distortion function is optimized by generating a set of quantization codebooks through random trials, keeping the codebook that yields the lowest distortion. Comparisons with limited feedback approaches relying on random codebooks are provided, highlighting the importance of matching the codebook design to the cell statistics. Numerical results show a performance gain in scenarios with non-uniform user distributions. Further, we propose a scheme that exploits the limited channel knowledge at the base station to reduce the computational complexity of determining the beamforming vectors and of finding the optimal user set.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"111 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115428895","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641617
C. Panazio, A. S. Menezes, J. Romano
In this paper we propose a blind maximum ratio combining (MRC) technique along with an initialization method to improve the performance of the blind adaptive channel shortening algorithm called multicarrier equalization by restoration of redundancy (MERRY) in the 1times2 SIMO channel context. We show through analysis and simulations that the blind MRC technique allow us to take advantage of the spatial diversity improving considerably the performance of the MERRY algorithm in the SIMO context.
{"title":"Blind maximum ratio combining and channel shortening for cyclic prefixed systems","authors":"C. Panazio, A. S. Menezes, J. Romano","doi":"10.1109/SPAWC.2008.4641617","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641617","url":null,"abstract":"In this paper we propose a blind maximum ratio combining (MRC) technique along with an initialization method to improve the performance of the blind adaptive channel shortening algorithm called multicarrier equalization by restoration of redundancy (MERRY) in the 1times2 SIMO channel context. We show through analysis and simulations that the blind MRC technique allow us to take advantage of the spatial diversity improving considerably the performance of the MERRY algorithm in the SIMO context.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123894181","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641620
Yu Deng, A. Burr, Lingyang Song
We propose a differential spatial multiplexing (SM) scheme based on complex square orthogonal designs, referred to as differential orthogonal spatial multiplexing (DOSM). The receiver of DOSM does not require estimation of channel fading coefficients, channel power, signal power, or noise power to decode the data symbols and the decision is based on the two consecutively received codewords. A constellation rotation strategy is introduced to enhance the transmission rate. An upper bound of the pair-wise error probability (PEP) for DOSM in Rayleigh fading channels is derived. Based on this bound we propose design criteria for the constellation rotation angel and use them to search for the optimal rotation angle for PSK constellations. Simulation results show that the proposed DOSM outperforms the existing differential spatial multiplexing schemes in terms of error-rate performance over quasi-static and time-selective Rayleigh fading channels. Furthermore, it is estimated from the bound that DOSM is only 0.4 dB poorer than coherent SM in a two-input two-output system at high SNR. The computational complexity of DOSM is moderate among the differential SM systems.
{"title":"Differential spatial multiplexing from orthogonal designs","authors":"Yu Deng, A. Burr, Lingyang Song","doi":"10.1109/SPAWC.2008.4641620","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641620","url":null,"abstract":"We propose a differential spatial multiplexing (SM) scheme based on complex square orthogonal designs, referred to as differential orthogonal spatial multiplexing (DOSM). The receiver of DOSM does not require estimation of channel fading coefficients, channel power, signal power, or noise power to decode the data symbols and the decision is based on the two consecutively received codewords. A constellation rotation strategy is introduced to enhance the transmission rate. An upper bound of the pair-wise error probability (PEP) for DOSM in Rayleigh fading channels is derived. Based on this bound we propose design criteria for the constellation rotation angel and use them to search for the optimal rotation angle for PSK constellations. Simulation results show that the proposed DOSM outperforms the existing differential spatial multiplexing schemes in terms of error-rate performance over quasi-static and time-selective Rayleigh fading channels. Furthermore, it is estimated from the bound that DOSM is only 0.4 dB poorer than coherent SM in a two-input two-output system at high SNR. The computational complexity of DOSM is moderate among the differential SM systems.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124102595","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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