Pub Date : 2005-09-11DOI: 10.1109/PIMRC.2005.1651437
L. Sanguinetti, M. Morelli
We discuss channel acquisition and tracking in the uplink of a multi-carrier code-division multiple-access (MC-CDMA) system. Channel acquisition is performed jointly with noise power estimation following two different approaches. The first assumes independently faded subcarriers while the second exploits the fading correlation across the signal bandwidth to improve the system performance. Both schemes are based on maximum likelihood (ML) reasoning and exploit some training blocks carrying known symbols. Channel tracking is pursued through least-mean square (LMS) techniques, using data decisions provided by a partial parallel interference cancellation (PPIC) receiver
{"title":"Multiuser Channel Estimation and Tracking for MC-CDMA Uplink Transmissions","authors":"L. Sanguinetti, M. Morelli","doi":"10.1109/PIMRC.2005.1651437","DOIUrl":"https://doi.org/10.1109/PIMRC.2005.1651437","url":null,"abstract":"We discuss channel acquisition and tracking in the uplink of a multi-carrier code-division multiple-access (MC-CDMA) system. Channel acquisition is performed jointly with noise power estimation following two different approaches. The first assumes independently faded subcarriers while the second exploits the fading correlation across the signal bandwidth to improve the system performance. Both schemes are based on maximum likelihood (ML) reasoning and exploit some training blocks carrying known symbols. Channel tracking is pursued through least-mean square (LMS) techniques, using data decisions provided by a partial parallel interference cancellation (PPIC) receiver","PeriodicalId":248766,"journal":{"name":"2005 IEEE 16th International Symposium on Personal, Indoor and Mobile Radio Communications","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132738669","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 : 2005-09-11DOI: 10.1109/PIMRC.2005.1651846
P. Falconio, F. Catania, M. Amato, R. Cusani
The choose to perform a C-OFDM modulation directly by satellite makes the design of cost-effective new communication scenarios possible, in periods in which satellite communications call for a higher penetration in everyday services provision, avoiding the high costs of terrestrial-segment infrastructures to make the satellite signal exploitable by mobile users in urban environments. This paper focuses on the analysis of the performances of a C-OFDM-based communication scheme for the provision of a high quality and scalable bit rate radio signal over satellite links and exploitable in urban environments. Due to these preambles, the almost unemployed specifically satellite-oriented Mode-III of the DAB standard is considered, in conjunction with the design of an high-effective receiver based on soft-decision schemes, in cohabitation with almost very spread terrestrial DAB services. The degradations due to propagation and signal distortions introduced by the payload are also taken into account in the analysis of the transmission system
{"title":"High quality audio services over a L-band satellite link using COFDM with soft-decision","authors":"P. Falconio, F. Catania, M. Amato, R. Cusani","doi":"10.1109/PIMRC.2005.1651846","DOIUrl":"https://doi.org/10.1109/PIMRC.2005.1651846","url":null,"abstract":"The choose to perform a C-OFDM modulation directly by satellite makes the design of cost-effective new communication scenarios possible, in periods in which satellite communications call for a higher penetration in everyday services provision, avoiding the high costs of terrestrial-segment infrastructures to make the satellite signal exploitable by mobile users in urban environments. This paper focuses on the analysis of the performances of a C-OFDM-based communication scheme for the provision of a high quality and scalable bit rate radio signal over satellite links and exploitable in urban environments. Due to these preambles, the almost unemployed specifically satellite-oriented Mode-III of the DAB standard is considered, in conjunction with the design of an high-effective receiver based on soft-decision schemes, in cohabitation with almost very spread terrestrial DAB services. The degradations due to propagation and signal distortions introduced by the payload are also taken into account in the analysis of the transmission system","PeriodicalId":248766,"journal":{"name":"2005 IEEE 16th International Symposium on Personal, Indoor and Mobile Radio Communications","volume":"266 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133537349","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 : 2005-09-11DOI: 10.1109/PIMRC.2005.1651854
R. Rembarz, S. Baucke, P. Mähönen
With network operators migrating from circuit-switched networks to IP networks, the need for a concept to provide operator grade trunk signaling over IP arises. A solution to enable signaling transport over IP is defined by the IETF SIGTRAN framework that allows for interworking with the Signaling System No. 7 (SS7). SIGTRAN is based on the stream control transmission protocol (SCTP) that also has a built-in redundancy mechanism, which allows switching to an alternative destination address (failover). Existing work showed that a failover performance comparable to SS7 can be achieved by aggressively setting the SCTP protocol parameters. However, this brings about possible stability issues because these parameter settings seriously impair the protocol mechanisms responsible for reacting to delay variations and congestion situations. We propose a set of network redundancy mechanisms that resolve most network failures transparently to SCTP. In order to eliminate possible stability issues, we use the default SCTP protocol parameters. Simulation results confirm that the proposed architecture can noticeably improve the robustness to concurrent network failures and achieve a similar delay behavior without jeopardizing the protocol stability
{"title":"Enhancing resilience for high availability IP-based signaling transport","authors":"R. Rembarz, S. Baucke, P. Mähönen","doi":"10.1109/PIMRC.2005.1651854","DOIUrl":"https://doi.org/10.1109/PIMRC.2005.1651854","url":null,"abstract":"With network operators migrating from circuit-switched networks to IP networks, the need for a concept to provide operator grade trunk signaling over IP arises. A solution to enable signaling transport over IP is defined by the IETF SIGTRAN framework that allows for interworking with the Signaling System No. 7 (SS7). SIGTRAN is based on the stream control transmission protocol (SCTP) that also has a built-in redundancy mechanism, which allows switching to an alternative destination address (failover). Existing work showed that a failover performance comparable to SS7 can be achieved by aggressively setting the SCTP protocol parameters. However, this brings about possible stability issues because these parameter settings seriously impair the protocol mechanisms responsible for reacting to delay variations and congestion situations. We propose a set of network redundancy mechanisms that resolve most network failures transparently to SCTP. In order to eliminate possible stability issues, we use the default SCTP protocol parameters. Simulation results confirm that the proposed architecture can noticeably improve the robustness to concurrent network failures and achieve a similar delay behavior without jeopardizing the protocol stability","PeriodicalId":248766,"journal":{"name":"2005 IEEE 16th International Symposium on Personal, Indoor and Mobile Radio Communications","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134390656","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 : 2005-09-11DOI: 10.1109/PIMRC.2005.1651938
K. Sayrafian-Pour, D. Kaspar
A simple technique to estimate the position of a given mobile source inside a building is based on the received signal strength. For this methodology to have a reasonable accuracy, radio visibility of the mobile by at least three access points is required. To reduce the number of the required access points and therefore, simplify the underlying coverage design problem, we propose a new scheme that takes into account the distribution of RF energy around the receiver. In other words, we assume that the receiver is equipped with a circular antenna with beamforming capability. In this way, the spatial spectrum of the received power can be measured by rotating the antenna beam around the 360-degree field of view. This spatial spectrum can be used by a single receiver as a mean for estimating the position of a mobile transmitter. In this paper, we investigate the feasibility of this methodology, and show the improvement achieved in the positioning accuracy
{"title":"Indoor positioning using spatial power spectrum","authors":"K. Sayrafian-Pour, D. Kaspar","doi":"10.1109/PIMRC.2005.1651938","DOIUrl":"https://doi.org/10.1109/PIMRC.2005.1651938","url":null,"abstract":"A simple technique to estimate the position of a given mobile source inside a building is based on the received signal strength. For this methodology to have a reasonable accuracy, radio visibility of the mobile by at least three access points is required. To reduce the number of the required access points and therefore, simplify the underlying coverage design problem, we propose a new scheme that takes into account the distribution of RF energy around the receiver. In other words, we assume that the receiver is equipped with a circular antenna with beamforming capability. In this way, the spatial spectrum of the received power can be measured by rotating the antenna beam around the 360-degree field of view. This spatial spectrum can be used by a single receiver as a mean for estimating the position of a mobile transmitter. In this paper, we investigate the feasibility of this methodology, and show the improvement achieved in the positioning accuracy","PeriodicalId":248766,"journal":{"name":"2005 IEEE 16th International Symposium on Personal, Indoor and Mobile Radio Communications","volume":"2021 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133810146","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 : 2005-09-11DOI: 10.1109/PIMRC.2005.1651797
Cooperation amongst heterogeneous mobile radio systems will be an indispensable feature of 'beyond 3G'. One key mechanism thereby serving as enabling technique for system integration will be the vertical handover (VHO) between different radio networks. Optimal handover control thereby is very important for which the present paper investigates a new algorithm for accurate VHO trigger generation. Taking the own position as input, mapping with location-based measurements from other stations is accomplished to decide for heterogeneous system coverage. Special interest thereby is laid on the fact that localization techniques inherently suffer from imprecision. Accurate trigger generation hence needs to overcome the impact of erroneous position information
{"title":"Performance evaluation of accurate trigger generation for vertical handover","authors":"","doi":"10.1109/PIMRC.2005.1651797","DOIUrl":"https://doi.org/10.1109/PIMRC.2005.1651797","url":null,"abstract":"Cooperation amongst heterogeneous mobile radio systems will be an indispensable feature of 'beyond 3G'. One key mechanism thereby serving as enabling technique for system integration will be the vertical handover (VHO) between different radio networks. Optimal handover control thereby is very important for which the present paper investigates a new algorithm for accurate VHO trigger generation. Taking the own position as input, mapping with location-based measurements from other stations is accomplished to decide for heterogeneous system coverage. Special interest thereby is laid on the fact that localization techniques inherently suffer from imprecision. Accurate trigger generation hence needs to overcome the impact of erroneous position information","PeriodicalId":248766,"journal":{"name":"2005 IEEE 16th International Symposium on Personal, Indoor and Mobile Radio Communications","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115185239","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 : 2005-09-11DOI: 10.1109/PIMRC.2005.1651699
J. Včelák, J. Sýkora
In this paper, we present the extended transfer bound analysis for the error performance of a general trellis code in the channel with the overall correlated continuous valued nuisance parameters. We introduce proper parameter model and include it into a new extended form of the transfer function. In this way, both, the new additional parameter space and the original error space are incorporated into system error analysis. An example application with simple trellis code and Rayleigh fading channel is investigated in order to demonstrate the functionality of the principle. Computer simulation results are presented for two different codes and various fading scenarios, and comparisons are made among analytical and measured system error performances. It was shown that for fading amplitude our approach was able to predict correct error asymptotes
{"title":"Extended transfer bound error analysis in the presence of channel random nuisance parameter","authors":"J. Včelák, J. Sýkora","doi":"10.1109/PIMRC.2005.1651699","DOIUrl":"https://doi.org/10.1109/PIMRC.2005.1651699","url":null,"abstract":"In this paper, we present the extended transfer bound analysis for the error performance of a general trellis code in the channel with the overall correlated continuous valued nuisance parameters. We introduce proper parameter model and include it into a new extended form of the transfer function. In this way, both, the new additional parameter space and the original error space are incorporated into system error analysis. An example application with simple trellis code and Rayleigh fading channel is investigated in order to demonstrate the functionality of the principle. Computer simulation results are presented for two different codes and various fading scenarios, and comparisons are made among analytical and measured system error performances. It was shown that for fading amplitude our approach was able to predict correct error asymptotes","PeriodicalId":248766,"journal":{"name":"2005 IEEE 16th International Symposium on Personal, Indoor and Mobile Radio Communications","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114788144","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 : 2005-09-11DOI: 10.1109/PIMRC.2005.1651591
H. Jenkac, T. Stockhammer, Wen Xu
In this paper different means for adding reliability in different protocol layers are discussed, in order to reliably broadcast multimedia data within existing wireless networks. In particular, we investigate the performance of additional forward error correction in the physical layer, the radio link control layer, and the RTP layer for multimedia broadcast and multicast services over GERAN systems. Advantages and drawbacks when applying means for reliability in different layers are shown. We introduce a simple receiver modification, referred to as permeable-layer receiver (PLR), which exploits traditionally useless information at the receiver, while the transmitter is kept unchanged. Significant performance gains are reported. Finally, the application to H.264/AVC based wireless video broadcast is discussed and the performance of different system designs for video transmission is shown
{"title":"Cross-layer issues and forward error correction for wireless video broadcast","authors":"H. Jenkac, T. Stockhammer, Wen Xu","doi":"10.1109/PIMRC.2005.1651591","DOIUrl":"https://doi.org/10.1109/PIMRC.2005.1651591","url":null,"abstract":"In this paper different means for adding reliability in different protocol layers are discussed, in order to reliably broadcast multimedia data within existing wireless networks. In particular, we investigate the performance of additional forward error correction in the physical layer, the radio link control layer, and the RTP layer for multimedia broadcast and multicast services over GERAN systems. Advantages and drawbacks when applying means for reliability in different layers are shown. We introduce a simple receiver modification, referred to as permeable-layer receiver (PLR), which exploits traditionally useless information at the receiver, while the transmitter is kept unchanged. Significant performance gains are reported. Finally, the application to H.264/AVC based wireless video broadcast is discussed and the performance of different system designs for video transmission is shown","PeriodicalId":248766,"journal":{"name":"2005 IEEE 16th International Symposium on Personal, Indoor and Mobile Radio Communications","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114486176","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 : 2005-09-11DOI: 10.1109/PIMRC.2005.1651703
O. May, L. Schumacher, Xavier Dubois
As far as transfer reliability is concerned, the wireless segment of UTRAN is the weakest part of an Internet session. To overcome this imperfection, the RLC protocol features a link-level retransmission mechanism. In this paper, we show by analytical means and computer simulations that for a given block error rate (BLER), the maximum number of RLC transmissions has a very important impact on TCP performance, both round trip time (RTT) and throughput. We extend the link level automatic repeat request model proposed by Peisa et al. (2001) to be able to set a maximum number of RLC transmissions, and with the help of Padhye's TCP throughput model (2000), we determine the corresponding throughput analytically. We also show that, knowing the current BLER, a network operator may tune the maximum number of retransmissions either to reduce the RTT or to increase the throughput
{"title":"Optimum Number of RLC Retransmissions for Best TCP Performance in UTRAN","authors":"O. May, L. Schumacher, Xavier Dubois","doi":"10.1109/PIMRC.2005.1651703","DOIUrl":"https://doi.org/10.1109/PIMRC.2005.1651703","url":null,"abstract":"As far as transfer reliability is concerned, the wireless segment of UTRAN is the weakest part of an Internet session. To overcome this imperfection, the RLC protocol features a link-level retransmission mechanism. In this paper, we show by analytical means and computer simulations that for a given block error rate (BLER), the maximum number of RLC transmissions has a very important impact on TCP performance, both round trip time (RTT) and throughput. We extend the link level automatic repeat request model proposed by Peisa et al. (2001) to be able to set a maximum number of RLC transmissions, and with the help of Padhye's TCP throughput model (2000), we determine the corresponding throughput analytically. We also show that, knowing the current BLER, a network operator may tune the maximum number of retransmissions either to reduce the RTT or to increase the throughput","PeriodicalId":248766,"journal":{"name":"2005 IEEE 16th International Symposium on Personal, Indoor and Mobile Radio Communications","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115391934","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 : 2005-09-11DOI: 10.1109/PIMRC.2005.1651402
Azadeh Ettefagh, M. Kuhn, B. Cheetham, A. Wittneben
This paper concerns the coverage range of a high quality voice over wireless local area network (VoWLAN) system based on the IEEE 802.11a standard. Techniques for enhancing the coverage range of each access point (AP) using co-located and distributed antenna diversity schemes are proposed and it is shown that the number of required APs and therefore the infrastructure cost may thus be reduced. Comparisons are made between the coverage range of the 802.11a and that of DECT (digital enhanced cordless telecommunication), and simulations and channel measurements devised for predicting the effect of diversity techniques on the range of APs are described. The results of two different measurement campaigns are presented, one with co-located antennas and the other with locally distributed antennas. The coverage enhancement gained within these scenarios by employing diversity techniques is thus deduced
{"title":"Comparison of Distributed and Co-located Antenna Diversity Schemes for the Coverage Improvement of VoWLAN Systems","authors":"Azadeh Ettefagh, M. Kuhn, B. Cheetham, A. Wittneben","doi":"10.1109/PIMRC.2005.1651402","DOIUrl":"https://doi.org/10.1109/PIMRC.2005.1651402","url":null,"abstract":"This paper concerns the coverage range of a high quality voice over wireless local area network (VoWLAN) system based on the IEEE 802.11a standard. Techniques for enhancing the coverage range of each access point (AP) using co-located and distributed antenna diversity schemes are proposed and it is shown that the number of required APs and therefore the infrastructure cost may thus be reduced. Comparisons are made between the coverage range of the 802.11a and that of DECT (digital enhanced cordless telecommunication), and simulations and channel measurements devised for predicting the effect of diversity techniques on the range of APs are described. The results of two different measurement campaigns are presented, one with co-located antennas and the other with locally distributed antennas. The coverage enhancement gained within these scenarios by employing diversity techniques is thus deduced","PeriodicalId":248766,"journal":{"name":"2005 IEEE 16th International Symposium on Personal, Indoor and Mobile Radio Communications","volume":"97 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123592061","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 : 2005-09-11DOI: 10.1109/PIMRC.2005.1651845
P. Pace, D. Pace, S. Marano
The need of new wireless communication infrastructure which can provide high-speed multimedia mobile communication service to users who are not satisfied with low-speed data and voice service provided by existing wireless network are rapidly increasing. Cellular communications using high altitude platform (HAPs) are studied for next generation broadband wireless network providing also third generation (3G) mobile services. The connection admission control issue in a HAP-UMTS communication system represents a key problem in order to increase the capacity in term of admitted users preserving the agreement quality of service. In this paper we propose a novel strategy for the admission procedure based on dynamic power sharing in order to guarantee an high fairness level to all users of the projected cellular system. Simulation results show that the proposed CAC scheme can achieve good performances managing different mixed traffic scenarios
{"title":"An HAP-UMTS integrated system supporting efficient admission control scheme for mixed traffic sources","authors":"P. Pace, D. Pace, S. Marano","doi":"10.1109/PIMRC.2005.1651845","DOIUrl":"https://doi.org/10.1109/PIMRC.2005.1651845","url":null,"abstract":"The need of new wireless communication infrastructure which can provide high-speed multimedia mobile communication service to users who are not satisfied with low-speed data and voice service provided by existing wireless network are rapidly increasing. Cellular communications using high altitude platform (HAPs) are studied for next generation broadband wireless network providing also third generation (3G) mobile services. The connection admission control issue in a HAP-UMTS communication system represents a key problem in order to increase the capacity in term of admitted users preserving the agreement quality of service. In this paper we propose a novel strategy for the admission procedure based on dynamic power sharing in order to guarantee an high fairness level to all users of the projected cellular system. Simulation results show that the proposed CAC scheme can achieve good performances managing different mixed traffic scenarios","PeriodicalId":248766,"journal":{"name":"2005 IEEE 16th International Symposium on Personal, Indoor and Mobile Radio Communications","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123040036","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：