Pub Date : 2011-11-01DOI: 10.1109/ISWCS.2011.6125365
Wolfgang Mennerich, W. Zirwas
Cooperative multipoint transmission (CoMP) in cellular systems is a widely discussed topic for future cellular networks. A main challenge therein is the limited size of practical realizable cooperation areas that entails many strong interfering cells in adjacent cooperation areas. This has been partly overcome by our so called partial CoMP concept, presented on several opportunities in 2010. Now, as further improvement, the so called ‘tortoise concept’ is proposed in this article. This is essentially an interference shaping method, realized with a three-dimensional wideband beamforming to minimize interference between cooperation areas. On top of the wideband beams, a central joint preprocessing cancels interference within the CA. This results in a strong mitigation of the total interference power with large performance gains.
{"title":"Combined zeroforcing with wideband beamforming for interference mitigation in cooperative cellular radio networks","authors":"Wolfgang Mennerich, W. Zirwas","doi":"10.1109/ISWCS.2011.6125365","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125365","url":null,"abstract":"Cooperative multipoint transmission (CoMP) in cellular systems is a widely discussed topic for future cellular networks. A main challenge therein is the limited size of practical realizable cooperation areas that entails many strong interfering cells in adjacent cooperation areas. This has been partly overcome by our so called partial CoMP concept, presented on several opportunities in 2010. Now, as further improvement, the so called ‘tortoise concept’ is proposed in this article. This is essentially an interference shaping method, realized with a three-dimensional wideband beamforming to minimize interference between cooperation areas. On top of the wideband beams, a central joint preprocessing cancels interference within the CA. This results in a strong mitigation of the total interference power with large performance gains.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115557110","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125342
A. Weber, Antoni Bestard
LTE and LTE Advanced system performance evaluation is mainly done by simulations based on standardized assumptions and methodology. Multiple Input Multiple Output (MIMO) antenna systems require a spatial channel model. Important antenna types are cross-polarized antenna structures which are simulated based on a cross-polarization extension of the spatial channel model. In this paper we show some shortcomings of the widely used X-Pol channel model and we present a solution based on coordinate transformation.
{"title":"Modeling of X-pol antennas for LTE system simulation","authors":"A. Weber, Antoni Bestard","doi":"10.1109/ISWCS.2011.6125342","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125342","url":null,"abstract":"LTE and LTE Advanced system performance evaluation is mainly done by simulations based on standardized assumptions and methodology. Multiple Input Multiple Output (MIMO) antenna systems require a spatial channel model. Important antenna types are cross-polarized antenna structures which are simulated based on a cross-polarization extension of the spatial channel model. In this paper we show some shortcomings of the widely used X-Pol channel model and we present a solution based on coordinate transformation.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"123 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124186529","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125395
Hoc Phan, T. Duong, H. Zepernick
In this paper, we analyze the outage performance of an opportunistic decode-and-forward (DF) relaying coded cooperation network over independent, and identically distributed Nakagami-m fading channels. In this scheme, cooperative diversity gain is obtained by integrating opportunistic relaying (OR) selection with channel coding. We have derived an analytical expression for the outage probability (OP) of the considered coded cooperation networks for both error-free relays and errors at the relays. Furthermore, for comparison, we derive an expression for the OP of a conventional OR cooperative network. For both systems, it has been observed that the achievable diversity gain is the same. However, the coded cooperation scheme achieves higher coding gain than the conventional cooperative scheme. Finally, numerical results are provided showing a tight match between the Monte Carlo simulations and the analytical curves.
{"title":"Outage performance for opportunistic decode-and-forward relaying coded cooperation networks over Nakagami-m fading","authors":"Hoc Phan, T. Duong, H. Zepernick","doi":"10.1109/ISWCS.2011.6125395","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125395","url":null,"abstract":"In this paper, we analyze the outage performance of an opportunistic decode-and-forward (DF) relaying coded cooperation network over independent, and identically distributed Nakagami-m fading channels. In this scheme, cooperative diversity gain is obtained by integrating opportunistic relaying (OR) selection with channel coding. We have derived an analytical expression for the outage probability (OP) of the considered coded cooperation networks for both error-free relays and errors at the relays. Furthermore, for comparison, we derive an expression for the OP of a conventional OR cooperative network. For both systems, it has been observed that the achievable diversity gain is the same. However, the coded cooperation scheme achieves higher coding gain than the conventional cooperative scheme. Finally, numerical results are provided showing a tight match between the Monte Carlo simulations and the analytical curves.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116948205","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125318
Najmeh Madani
This paper examines the two-way relay channel (TWRC) in a spectrum-sharing environment. Two secondary users, a primary user and a relay are the involved nodes in our model. The transmit power of the secondary users and the relay are adapted optimally to approach the maximum achievable sum-rate while keeping the interference level at the primary user below a threshold. Numerical simulations are conducted to demonstrate the performance of the proposed scenario.
{"title":"Sum-rate analysis of the two-way relay channel in spectrum-sharing environments","authors":"Najmeh Madani","doi":"10.1109/ISWCS.2011.6125318","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125318","url":null,"abstract":"This paper examines the two-way relay channel (TWRC) in a spectrum-sharing environment. Two secondary users, a primary user and a relay are the involved nodes in our model. The transmit power of the secondary users and the relay are adapted optimally to approach the maximum achievable sum-rate while keeping the interference level at the primary user below a threshold. Numerical simulations are conducted to demonstrate the performance of the proposed scenario.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"143 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115998319","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125335
I. Viering, B. Wegmann, Andreas Lobinger, A. Awada, H. Martikainen
Mobility robustness is often understood as making the radio link Doppler-resistent. However, guaranteeing proper cell changes, e.g. handovers, is another, as important and at least as challenging aspect beyond Doppler and wide sense stationarity (WSS) assumption. This paper tries to describe the complex optimization problem with scientific methods, in order to catalyze future academic work in the interesting field of minimizing handover problems. Simulation results will be presented for intra-frequency mobility robustness optimization (MRO) distinguishing network-wide, cell-specific and cell-pair specific optimization.
{"title":"Mobility robustness optimization beyond Doppler effect and WSS assumption","authors":"I. Viering, B. Wegmann, Andreas Lobinger, A. Awada, H. Martikainen","doi":"10.1109/ISWCS.2011.6125335","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125335","url":null,"abstract":"Mobility robustness is often understood as making the radio link Doppler-resistent. However, guaranteeing proper cell changes, e.g. handovers, is another, as important and at least as challenging aspect beyond Doppler and wide sense stationarity (WSS) assumption. This paper tries to describe the complex optimization problem with scientific methods, in order to catalyze future academic work in the interesting field of minimizing handover problems. Simulation results will be presented for intra-frequency mobility robustness optimization (MRO) distinguishing network-wide, cell-specific and cell-pair specific optimization.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129789471","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125433
H. Izumikawa, T. Matsunaka, Y. Kishi
In challenged network environments like tunnels, a mobile node can suffer from a sudden disruption in mobile services, e.g., the abrupt ending of an application session, due to factors like coverage holes. To tackle this issue, there is an approach that provides tolerance for disruptions or disconnections in the network architecture, in which proxy functions in the network and the mobile node conceal the disruption of the wireless link from users and application servers. After the wireless link is re-established, the services the user enjoys are resumed. However, even if such a disruption-tolerant function avoids the direct negative effects of a disruption, i.e., the sudden end of an application session, the services could still end due to an application idle timer. In this paper, we propose a dynamic buffering method, named application idle timer retardation buffering (ARB), to deal with the application idle timeout issue. The proxy function in a mobile node has a buffer for incoming data from the network and queues data for only a brief moment before forwarding it to an application. When link connectivity is lost, the proxy function forwards queued data to the end-user application at a very low rate in order to delay application idle timer expiration by repeatedly resetting the timer. We implemented ARB in PCs and conducted field tests. The results of the ARB field test indicate that ARB maintains continuity despite communication interruptions as much as eleven times longer than could be handled without it, without throughput degradation.
{"title":"Retarding application idle timer expiration for service resumption in challenged network","authors":"H. Izumikawa, T. Matsunaka, Y. Kishi","doi":"10.1109/ISWCS.2011.6125433","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125433","url":null,"abstract":"In challenged network environments like tunnels, a mobile node can suffer from a sudden disruption in mobile services, e.g., the abrupt ending of an application session, due to factors like coverage holes. To tackle this issue, there is an approach that provides tolerance for disruptions or disconnections in the network architecture, in which proxy functions in the network and the mobile node conceal the disruption of the wireless link from users and application servers. After the wireless link is re-established, the services the user enjoys are resumed. However, even if such a disruption-tolerant function avoids the direct negative effects of a disruption, i.e., the sudden end of an application session, the services could still end due to an application idle timer. In this paper, we propose a dynamic buffering method, named application idle timer retardation buffering (ARB), to deal with the application idle timeout issue. The proxy function in a mobile node has a buffer for incoming data from the network and queues data for only a brief moment before forwarding it to an application. When link connectivity is lost, the proxy function forwards queued data to the end-user application at a very low rate in order to delay application idle timer expiration by repeatedly resetting the timer. We implemented ARB in PCs and conducted field tests. The results of the ARB field test indicate that ARB maintains continuity despite communication interruptions as much as eleven times longer than could be handled without it, without throughput degradation.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128483903","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125371
S. Corroy, Andreas Bollig, R. Mathar
In this paper, we consider the problem of sensing a frequency spectrum in a distributed manner using as few measurements as possible while still guaranteeing a low detection error. To achieve this goal we use the newly developed technique of matrix completion which enables to recover a low rank matrix from a small subset of its entries. We model the sensed bandwidth at different cognitive radios as a spectrum matrix. It has been shown that in many cases the spectrum used by a primary user is underutilized. Therefore the spectrum matrix often has a low rank structure. By taking few measurements at several cognitive radios and reconstructing the matrix at a fusion center, we can dramatically reduce the required number of samples to reconstruct the utilization of the bandwidth. This is a key enabler for efficient and reliable spectrum reuse.
{"title":"Distributed sensing of a slowly time-varying sparse spectrum using matrix completion","authors":"S. Corroy, Andreas Bollig, R. Mathar","doi":"10.1109/ISWCS.2011.6125371","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125371","url":null,"abstract":"In this paper, we consider the problem of sensing a frequency spectrum in a distributed manner using as few measurements as possible while still guaranteeing a low detection error. To achieve this goal we use the newly developed technique of matrix completion which enables to recover a low rank matrix from a small subset of its entries. We model the sensed bandwidth at different cognitive radios as a spectrum matrix. It has been shown that in many cases the spectrum used by a primary user is underutilized. Therefore the spectrum matrix often has a low rank structure. By taking few measurements at several cognitive radios and reconstructing the matrix at a fusion center, we can dramatically reduce the required number of samples to reconstruct the utilization of the bandwidth. This is a key enabler for efficient and reliable spectrum reuse.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"12 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132433487","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125452
P. Rossi, G. Romano, D. Ciuonzo, F. Palmieri
This paper deals with multiuser MIMO-OFDM systems in which single-antenna users transmit encoded data to a common receiver employing iterative multiuser detection. We focus on uplink communications in overloaded scenarios, i.e. the feasibility for the system to support a number of users larger than the number of receive antennas. We assume that perfect channel state information is available at the receiver, and perfect, analog and instantaneous feedback from the receiver to the users. We show how simple power allocation at user location, based on gain design for asymptotic separation at receiver location, makes overloading feasible. Numerical simulations show the benefit of the proposed approach.
{"title":"Gain design and power allocation for overloaded MIMO-OFDM systems with channel state information and iterative multiuser detection","authors":"P. Rossi, G. Romano, D. Ciuonzo, F. Palmieri","doi":"10.1109/ISWCS.2011.6125452","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125452","url":null,"abstract":"This paper deals with multiuser MIMO-OFDM systems in which single-antenna users transmit encoded data to a common receiver employing iterative multiuser detection. We focus on uplink communications in overloaded scenarios, i.e. the feasibility for the system to support a number of users larger than the number of receive antennas. We assume that perfect channel state information is available at the receiver, and perfect, analog and instantaneous feedback from the receiver to the users. We show how simple power allocation at user location, based on gain design for asymptotic separation at receiver location, makes overloading feasible. Numerical simulations show the benefit of the proposed approach.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127768114","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125387
Shunfu Jin, Wuyi Yue
In this paper, we propose a novel DiffServ mechanism for multi-traffic Wireless Sensor Networks (M-WSNs) supporting real-time traffic and non-real-time traffic simultaneously. This mechanism will reduce the average transmission time of the real-time traffic and improve the transmission reliability of the non-real-time traffic when one cluster transmits its packets to the next cluster. The packets of the non-real-time traffic will be queueing at a finite buffer of the cluster to be transmitted following a First-Come First-Serve (FCFS) strategy. The packets of the real-time traffic will immediately occupy the channel between two adjacent clusters preemptively and will be transmitted without queueing if there is no other packet of realtime traffic being transmitted. A discrete-time queueing model with two classes of traffic is built with a finite cluster capacity in order to describe the working principle of the novel DiffServ mechanism. By using the method of a two-dimensional Markov chain, the formulas for the performance measures in terms of drop rate, average response time, system throughput and energy saving ratio are given. Finally, numerical results are given to demonstrate the influence of the system parameters on the system performance.
{"title":"Performance evaluation of multi-traffic on wireless sensor networks using a novel Diffserv mechanism","authors":"Shunfu Jin, Wuyi Yue","doi":"10.1109/ISWCS.2011.6125387","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125387","url":null,"abstract":"In this paper, we propose a novel DiffServ mechanism for multi-traffic Wireless Sensor Networks (M-WSNs) supporting real-time traffic and non-real-time traffic simultaneously. This mechanism will reduce the average transmission time of the real-time traffic and improve the transmission reliability of the non-real-time traffic when one cluster transmits its packets to the next cluster. The packets of the non-real-time traffic will be queueing at a finite buffer of the cluster to be transmitted following a First-Come First-Serve (FCFS) strategy. The packets of the real-time traffic will immediately occupy the channel between two adjacent clusters preemptively and will be transmitted without queueing if there is no other packet of realtime traffic being transmitted. A discrete-time queueing model with two classes of traffic is built with a finite cluster capacity in order to describe the working principle of the novel DiffServ mechanism. By using the method of a two-dimensional Markov chain, the formulas for the performance measures in terms of drop rate, average response time, system throughput and energy saving ratio are given. Finally, numerical results are given to demonstrate the influence of the system parameters on the system performance.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127777004","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125424
A. Angierski, S. Schedler, V. Kühn
In the past decade network coding has become a broad research area. Since the benefit of relays is well-known they have been considered within countless studies. Furthermore, it seems to be widely accepted that user cooperation promises a huge benefit. This paper considers a two-user relay network with a TDMA structure. Several cooperative and non-cooperative transmission schemes are analyzed. The cooperative ones will process the incoming information from several users at the relay jointly before forwarding it to the destination. The relay is restricted to forward information in just one time slot. Thus, it can either forward a subset of the received information or it has to change the coded modulation scheme by increasing the code rate or choosing a larger modulation alphabet. Using numerical simulations, five different strategies are analyzed. It will be illustrated that the performance of cooperative schemes deteriorates significantly when the relay is not able to decode successfully. Especially in asymmetric scenarios, the gains obtained by cooperation for the weaker user are much less than the corresponding losses of the stronger user so that the overall system performance degrades.
{"title":"Investigations on cooperative transmission for the multiple access relay channel","authors":"A. Angierski, S. Schedler, V. Kühn","doi":"10.1109/ISWCS.2011.6125424","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125424","url":null,"abstract":"In the past decade network coding has become a broad research area. Since the benefit of relays is well-known they have been considered within countless studies. Furthermore, it seems to be widely accepted that user cooperation promises a huge benefit. This paper considers a two-user relay network with a TDMA structure. Several cooperative and non-cooperative transmission schemes are analyzed. The cooperative ones will process the incoming information from several users at the relay jointly before forwarding it to the destination. The relay is restricted to forward information in just one time slot. Thus, it can either forward a subset of the received information or it has to change the coded modulation scheme by increasing the code rate or choosing a larger modulation alphabet. Using numerical simulations, five different strategies are analyzed. It will be illustrated that the performance of cooperative schemes deteriorates significantly when the relay is not able to decode successfully. Especially in asymmetric scenarios, the gains obtained by cooperation for the weaker user are much less than the corresponding losses of the stronger user so that the overall system performance degrades.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127787258","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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