Pub Date : 2018-08-01DOI: 10.1109/ISWCS.2018.8491227
S. Pfletschinger, M. Navarro
In this paper, we establish a simple model for the exchange of messages in a vehicular network and we consider fundamental limits on the achievable data rate. For a vehicular network, the exchange of data with other nearby vehicles is particularly important for traffic safety, e.g. for collision avoidance, but also for cooperative applications like platooning. These use cases are currently addressed by standards building on IEEE 802.11p, namely ITS-G5 and DSRC (dedicated short range communication), which encounter saturation problems at high vehicle densities. For this reason, we take a step back and ask for the fundamental limits for the common data rate in a vehicular network. After defining a simple single-lane model and the corresponding capacity limits for some basic multiple-access schemes, we present results for a more realistic setting. For both scenarios, non-orthogonal multiple-access (NOMA) yields the best results.
{"title":"Non-Orthogonal Multiple Access for Vehicular Communication","authors":"S. Pfletschinger, M. Navarro","doi":"10.1109/ISWCS.2018.8491227","DOIUrl":"https://doi.org/10.1109/ISWCS.2018.8491227","url":null,"abstract":"In this paper, we establish a simple model for the exchange of messages in a vehicular network and we consider fundamental limits on the achievable data rate. For a vehicular network, the exchange of data with other nearby vehicles is particularly important for traffic safety, e.g. for collision avoidance, but also for cooperative applications like platooning. These use cases are currently addressed by standards building on IEEE 802.11p, namely ITS-G5 and DSRC (dedicated short range communication), which encounter saturation problems at high vehicle densities. For this reason, we take a step back and ask for the fundamental limits for the common data rate in a vehicular network. After defining a simple single-lane model and the corresponding capacity limits for some basic multiple-access schemes, we present results for a more realistic setting. For both scenarios, non-orthogonal multiple-access (NOMA) yields the best results.","PeriodicalId":272951,"journal":{"name":"2018 15th International Symposium on Wireless Communication Systems (ISWCS)","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131533765","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 : 2018-08-01DOI: 10.1109/ISWCS.2018.8491222
S. Moghaddamnia, Martin Fuhrwerk, J. Peissig
One of the key issues of Digital Radio Mondiale (DRM) is green broadcasting. For wide area coverage, the use of high-power transmitters is essential. However, the applied transmission technology based on Orthogonal Frequency Division Multiplexing (OFDM) results in non-linearities in the emitted signal, low power efficiency, and high costs of transmitters. Digital predistortion is a promising scheme for power amplifier (PA) linearization. This paper presents an efficient approach to estimate the parameters of a digital predistorter based on adaptive filtering with direct learning architecture (DLA). A well-known algorithm for identifying and tracking the time-varying parameters of an unknown system is the recursive least squares (RLS) method with exponential/directional forgetting. In this paper, the efficiency of both exponential/directional forgetting techniques is investigated for different degrees of PA nonlinearities. On this basis, a new hybrid technique based on statistical properties of the PA input signal is proposed. The evaluation results show that for both scenarios, the statistic-based forgetting technique not only provides better accuracy but also is more robust against high PA nonlinearities.
{"title":"Use of Statistical Signal Properties for Adaptive Predistortion of High Power Amplifiers","authors":"S. Moghaddamnia, Martin Fuhrwerk, J. Peissig","doi":"10.1109/ISWCS.2018.8491222","DOIUrl":"https://doi.org/10.1109/ISWCS.2018.8491222","url":null,"abstract":"One of the key issues of Digital Radio Mondiale (DRM) is green broadcasting. For wide area coverage, the use of high-power transmitters is essential. However, the applied transmission technology based on Orthogonal Frequency Division Multiplexing (OFDM) results in non-linearities in the emitted signal, low power efficiency, and high costs of transmitters. Digital predistortion is a promising scheme for power amplifier (PA) linearization. This paper presents an efficient approach to estimate the parameters of a digital predistorter based on adaptive filtering with direct learning architecture (DLA). A well-known algorithm for identifying and tracking the time-varying parameters of an unknown system is the recursive least squares (RLS) method with exponential/directional forgetting. In this paper, the efficiency of both exponential/directional forgetting techniques is investigated for different degrees of PA nonlinearities. On this basis, a new hybrid technique based on statistical properties of the PA input signal is proposed. The evaluation results show that for both scenarios, the statistic-based forgetting technique not only provides better accuracy but also is more robust against high PA nonlinearities.","PeriodicalId":272951,"journal":{"name":"2018 15th International Symposium on Wireless Communication Systems (ISWCS)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128110578","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 : 2018-08-01DOI: 10.1109/ISWCS.2018.8491084
A. Shapin, Kittipong Kittichokechai, Niklas Andgart, Mårten Sundberg, Gustav Wikström
Ultra-reliable low latency communication (URLLC) is one of the new main use cases of 5G to be supported by both New Radio (NR) and Long Term Evolution (LTE) technologies. In the paper, latency and reliability of NR and LTE are studied to estimate expected URLLC performance on the physical layer. The simplified performance estimation model is used to evaluate the overall reliability combining results from different physical channels. The results show that both NR and LTE can fulfill URLLC reliability requirements with different transmission configurations and thereby at a cost of different spectral efficiencies.
{"title":"Physical Layer Performance for Low Latency and High Reliability in 5G","authors":"A. Shapin, Kittipong Kittichokechai, Niklas Andgart, Mårten Sundberg, Gustav Wikström","doi":"10.1109/ISWCS.2018.8491084","DOIUrl":"https://doi.org/10.1109/ISWCS.2018.8491084","url":null,"abstract":"Ultra-reliable low latency communication (URLLC) is one of the new main use cases of 5G to be supported by both New Radio (NR) and Long Term Evolution (LTE) technologies. In the paper, latency and reliability of NR and LTE are studied to estimate expected URLLC performance on the physical layer. The simplified performance estimation model is used to evaluate the overall reliability combining results from different physical channels. The results show that both NR and LTE can fulfill URLLC reliability requirements with different transmission configurations and thereby at a cost of different spectral efficiencies.","PeriodicalId":272951,"journal":{"name":"2018 15th International Symposium on Wireless Communication Systems (ISWCS)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115727543","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 : 2018-08-01DOI: 10.1109/ISWCS.2018.8491092
Bin Wang, Yongyu Chang, Minshan Xiang, Jingzhou Wu
Massive multiple-input multiple-output (MIMO) wireless communication refers to the idea equipping transmitters with a very large number of antennas, and has been shown to potentially allow for orders of magnitude improvement in spectral and energy efficiency by using relatively simple (linear) processing. In a multi-user MIMO (MU-MIMO) spatial multiplexing scheme, multiple users are scheduled in the same resource block (RB). In 3GPP Long Term Evolution (LTE) systems, single user MIMO (SU-MIMO) rank one precoding based channel quality indicator (CQI) reporting mechanism is reused for MU-MIMO. This is optimum for MU-MIMO if single user is served. This paper is to get an insight of the multi user CQI prediction. A method to estimate the multi user CQI from the reported rank 1 single user CQI is proposed for the space division multiple access (SDMA) mode and zero-forcing (ZF) precoding. Simulation results illustrate that the derived asymptotic value of the MU-MIMO CQI is very close to the real value of that.
{"title":"A Multiuser CQI Prediction Scheme with Channel Estimation Error in the Massive MIMO Networks","authors":"Bin Wang, Yongyu Chang, Minshan Xiang, Jingzhou Wu","doi":"10.1109/ISWCS.2018.8491092","DOIUrl":"https://doi.org/10.1109/ISWCS.2018.8491092","url":null,"abstract":"Massive multiple-input multiple-output (MIMO) wireless communication refers to the idea equipping transmitters with a very large number of antennas, and has been shown to potentially allow for orders of magnitude improvement in spectral and energy efficiency by using relatively simple (linear) processing. In a multi-user MIMO (MU-MIMO) spatial multiplexing scheme, multiple users are scheduled in the same resource block (RB). In 3GPP Long Term Evolution (LTE) systems, single user MIMO (SU-MIMO) rank one precoding based channel quality indicator (CQI) reporting mechanism is reused for MU-MIMO. This is optimum for MU-MIMO if single user is served. This paper is to get an insight of the multi user CQI prediction. A method to estimate the multi user CQI from the reported rank 1 single user CQI is proposed for the space division multiple access (SDMA) mode and zero-forcing (ZF) precoding. Simulation results illustrate that the derived asymptotic value of the MU-MIMO CQI is very close to the real value of that.","PeriodicalId":272951,"journal":{"name":"2018 15th International Symposium on Wireless Communication Systems (ISWCS)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122173935","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 : 2018-08-01DOI: 10.1109/ISWCS.2018.8491049
Robert M. Oliveira, R. D. Lamare
This paper presents a puncturing technique based on the channel polarization index for the design of rate-compatible polar codes in fifth generation (5G) wireless systems. The proposed strategy consists of two steps: we first generate the codeword message; then reduce the length of the codeword based on the channel polarization index, where channels with the smallest polarization indexes are punctured. We consider the proposed punctured polar codes with successive cancellation (SC) decoder and with Cyclic Redundancy Check (CRC) aided SC list (CA-SCL) decoder. Punctured bits are known to both encoder and decoder. The Polar Spectrum (PS) is then used for performance analysis of the puncturing technique. Simulations for 5G scenarios show that the proposed polar codes perform comparably to Low-Density Parity-Check (LDPC) codes.
{"title":"Puncturing Based on Polarization for Polar Codes in 5G Networks","authors":"Robert M. Oliveira, R. D. Lamare","doi":"10.1109/ISWCS.2018.8491049","DOIUrl":"https://doi.org/10.1109/ISWCS.2018.8491049","url":null,"abstract":"This paper presents a puncturing technique based on the channel polarization index for the design of rate-compatible polar codes in fifth generation (5G) wireless systems. The proposed strategy consists of two steps: we first generate the codeword message; then reduce the length of the codeword based on the channel polarization index, where channels with the smallest polarization indexes are punctured. We consider the proposed punctured polar codes with successive cancellation (SC) decoder and with Cyclic Redundancy Check (CRC) aided SC list (CA-SCL) decoder. Punctured bits are known to both encoder and decoder. The Polar Spectrum (PS) is then used for performance analysis of the puncturing technique. Simulations for 5G scenarios show that the proposed polar codes perform comparably to Low-Density Parity-Check (LDPC) codes.","PeriodicalId":272951,"journal":{"name":"2018 15th International Symposium on Wireless Communication Systems (ISWCS)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131651007","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 : 2018-08-01DOI: 10.1109/ISWCS.2018.8491083
Zijian Wang, L. Vandendorpe
Ahstract- The energy efficiency (EE) maximization problem is studied for the design of beamforming for multi-carrier multiuser systems. Nonlinear amplifier at each antenna as well as per-antenna power constraints at the transmitter are considered. The quality-of-service (QoS) of each user is guaranteed by a minimal transmission rate. Because the power allocation variables and the beamforming vectors are coupled in the original problem, which makes it difficult to handle, we split the problem into two subproblems. The first subproblem, which optimizes the power allocation, can be formulated as a geometric programming (GP) after the term related to power consumption is approximated as a monomial. The second subproblem, which optimizes the beamforming, is formulated as a second-order cone programming (SOCP). Numerical results illustrate the effect of EE maximization on rates and the effect of circuit power and amplifier efficiency on EE.
{"title":"Energy Efficient Beamforming Design Ior Multi-Carrier Multi-user Systems with Nonlinear Amplifiers","authors":"Zijian Wang, L. Vandendorpe","doi":"10.1109/ISWCS.2018.8491083","DOIUrl":"https://doi.org/10.1109/ISWCS.2018.8491083","url":null,"abstract":"Ahstract- The energy efficiency (EE) maximization problem is studied for the design of beamforming for multi-carrier multiuser systems. Nonlinear amplifier at each antenna as well as per-antenna power constraints at the transmitter are considered. The quality-of-service (QoS) of each user is guaranteed by a minimal transmission rate. Because the power allocation variables and the beamforming vectors are coupled in the original problem, which makes it difficult to handle, we split the problem into two subproblems. The first subproblem, which optimizes the power allocation, can be formulated as a geometric programming (GP) after the term related to power consumption is approximated as a monomial. The second subproblem, which optimizes the beamforming, is formulated as a second-order cone programming (SOCP). Numerical results illustrate the effect of EE maximization on rates and the effect of circuit power and amplifier efficiency on EE.","PeriodicalId":272951,"journal":{"name":"2018 15th International Symposium on Wireless Communication Systems (ISWCS)","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131283445","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 : 2018-08-01DOI: 10.1109/ISWCS.2018.8491203
A. Hoeller, R. Souza, O. A. López, H. Alves, M. Noronha-Neto, G. Brante
LoRA networks have been gaining momentum as an accessible and open solution for massive connectivity in the Internet-of- Things. Besides the popularity, however, academic research has shown that the technology has limitations. In particular to the connectivity argument, it became clear that massive coverage comes at the price of severely reduced duty cycles, and the increased number of users in the network significantly elevates packet loss due to collisions. In this paper, we exploit time diversity to increase the probability of successful packet delivery in LoRA uplink. We build on previous work to model the outage and coverage probabilities of LoRA channels and analyze the use of message replication to create signal diversity. We observed that there is an optimum number of message replicas that minimizes outage probability and avoids high collision probability. We validate the proposed model using numerical simulations.
{"title":"Exploiting Time Diversity of LoRa Networks Through Optimum Message Replication","authors":"A. Hoeller, R. Souza, O. A. López, H. Alves, M. Noronha-Neto, G. Brante","doi":"10.1109/ISWCS.2018.8491203","DOIUrl":"https://doi.org/10.1109/ISWCS.2018.8491203","url":null,"abstract":"LoRA networks have been gaining momentum as an accessible and open solution for massive connectivity in the Internet-of- Things. Besides the popularity, however, academic research has shown that the technology has limitations. In particular to the connectivity argument, it became clear that massive coverage comes at the price of severely reduced duty cycles, and the increased number of users in the network significantly elevates packet loss due to collisions. In this paper, we exploit time diversity to increase the probability of successful packet delivery in LoRA uplink. We build on previous work to model the outage and coverage probabilities of LoRA channels and analyze the use of message replication to create signal diversity. We observed that there is an optimum number of message replicas that minimizes outage probability and avoids high collision probability. We validate the proposed model using numerical simulations.","PeriodicalId":272951,"journal":{"name":"2018 15th International Symposium on Wireless Communication Systems (ISWCS)","volume":"144 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122808287","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 : 2018-08-01DOI: 10.1109/ISWCS.2018.8491094
Màrius Caus, A. Pastore, M. Navarro, T. Ramírez, C. Mosquera, N. Noels, N. Alagha, A. Pérez-Neira
The adoption of aggressive frequency reuse schemes along with interference management techniques has become the leading paradigm in satellite communications to increase the spectral efficiency. In general terms, one cannot rely on precoding techniques in the absence of channel phase information. Nevertheless, the availability of channel magnitude information, makes it possible to explore power-based separation of superimposed signals. In this paper, rate splitting (RS) ideas are exploited, whereby the separation of messages into private and public parts serves to improve the performance of successive cancellation decoding (SCD). Numerical results reveal that in some pertinent system scenarios, the proposed schemes achieve a larger rate region than that of orthogonal schemes that do not exploit the interference and other strategies that either do not allow beam cooperation or do not apply RS.
{"title":"Exploratory Analysis of Superposition Coding and Rate Splitting for Multibeam Satellite Systems","authors":"Màrius Caus, A. Pastore, M. Navarro, T. Ramírez, C. Mosquera, N. Noels, N. Alagha, A. Pérez-Neira","doi":"10.1109/ISWCS.2018.8491094","DOIUrl":"https://doi.org/10.1109/ISWCS.2018.8491094","url":null,"abstract":"The adoption of aggressive frequency reuse schemes along with interference management techniques has become the leading paradigm in satellite communications to increase the spectral efficiency. In general terms, one cannot rely on precoding techniques in the absence of channel phase information. Nevertheless, the availability of channel magnitude information, makes it possible to explore power-based separation of superimposed signals. In this paper, rate splitting (RS) ideas are exploited, whereby the separation of messages into private and public parts serves to improve the performance of successive cancellation decoding (SCD). Numerical results reveal that in some pertinent system scenarios, the proposed schemes achieve a larger rate region than that of orthogonal schemes that do not exploit the interference and other strategies that either do not allow beam cooperation or do not apply RS.","PeriodicalId":272951,"journal":{"name":"2018 15th International Symposium on Wireless Communication Systems (ISWCS)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117002326","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 : 2018-08-01DOI: 10.1109/ISWCS.2018.8491063
Z. Shao, R. Lamare, L. Landau
In this paper, we investigate adaptive channel estimation and linear interference mitigation for the uplink of large-scale antenna systems with I-bit analog-to-digital converters on each receive antenna. A novel low-resolution aware least-mean square channel estimation algorithm is proposed based on the low-complexity stochastic gradient descent method. Moreover, we also develop an algorithm for adaptively adjusting the parameters of the receive filter that performs mitigation of multiuser interference. In order to further improve the system performance, the proposed linear receiver is incorporated in an iterative detection and decoding scheme using short block length low-density parity-check codes. Simulation results show very good performance of the system in terms of mean square error and bit error rate.
{"title":"Adaptive Channel Estimation and Interference Mitigation for Large-Scale MIMO Systems with 1-Bit ADCs","authors":"Z. Shao, R. Lamare, L. Landau","doi":"10.1109/ISWCS.2018.8491063","DOIUrl":"https://doi.org/10.1109/ISWCS.2018.8491063","url":null,"abstract":"In this paper, we investigate adaptive channel estimation and linear interference mitigation for the uplink of large-scale antenna systems with I-bit analog-to-digital converters on each receive antenna. A novel low-resolution aware least-mean square channel estimation algorithm is proposed based on the low-complexity stochastic gradient descent method. Moreover, we also develop an algorithm for adaptively adjusting the parameters of the receive filter that performs mitigation of multiuser interference. In order to further improve the system performance, the proposed linear receiver is incorporated in an iterative detection and decoding scheme using short block length low-density parity-check codes. Simulation results show very good performance of the system in terms of mean square error and bit error rate.","PeriodicalId":272951,"journal":{"name":"2018 15th International Symposium on Wireless Communication Systems (ISWCS)","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114731130","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 : 2018-08-01DOI: 10.1109/iswcs.2018.8491074
M.N. de Sousa, R. Thoma
{"title":"Single Sensor RF Emitter Location Using Ray Tracing Multipath Exploitation","authors":"M.N. de Sousa, R. Thoma","doi":"10.1109/iswcs.2018.8491074","DOIUrl":"https://doi.org/10.1109/iswcs.2018.8491074","url":null,"abstract":"","PeriodicalId":272951,"journal":{"name":"2018 15th International Symposium on Wireless Communication Systems (ISWCS)","volume":"49 10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120898449","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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