Pub Date : 2003-07-09DOI: 10.1109/VETECS.2003.1207114
N. Enderle, X. Lagrange
In this paper, we propose a user satisfaction model for packet-switched services in next generation wireless networks for different radio resource allocation (RRA) strategies. Here, user satisfaction is seen as the joint effect of intrinsic service value and user perceived QoS which is seen as an increasing and concave function of network performance. The radio resource allocation process has to balance between power constraints and mean user satisfaction maximization. This optimization problem can be solved by the Lagrangian method and leads to a new scheduling algorithm. Then, we present other typical satisfaction functions for which the Lagrangian method also works. This leads to known algorithms such as max C/I scheduler or proportional fairness. By performing end-to-end dynamic simulations (TCP, RLC/MAC, WCDMA layer), we compare performance results in terms of user satisfaction and throughput distribution. The results show that a scheduling strategy always makes a trade-off between fairness and efficiency. We also show that it is possible to achieve service differentiation for packet-switched services by adjusting intrinsic service values.
{"title":"User satisfaction models and scheduling algorithms for packet-switched services in UMTS","authors":"N. Enderle, X. Lagrange","doi":"10.1109/VETECS.2003.1207114","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1207114","url":null,"abstract":"In this paper, we propose a user satisfaction model for packet-switched services in next generation wireless networks for different radio resource allocation (RRA) strategies. Here, user satisfaction is seen as the joint effect of intrinsic service value and user perceived QoS which is seen as an increasing and concave function of network performance. The radio resource allocation process has to balance between power constraints and mean user satisfaction maximization. This optimization problem can be solved by the Lagrangian method and leads to a new scheduling algorithm. Then, we present other typical satisfaction functions for which the Lagrangian method also works. This leads to known algorithms such as max C/I scheduler or proportional fairness. By performing end-to-end dynamic simulations (TCP, RLC/MAC, WCDMA layer), we compare performance results in terms of user satisfaction and throughput distribution. The results show that a scheduling strategy always makes a trade-off between fairness and efficiency. We also show that it is possible to achieve service differentiation for packet-switched services by adjusting intrinsic service values.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130254908","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 : 2003-06-22DOI: 10.1109/VETECS.2003.1207530
H. Son, Geun-sik Bae, Hung-Soo Lee
It is being examined that 2.3 GHz frequency band is withdrawn and redistributed at the same new service for efficient use of the radio resource in South Korea. In this paper, analysis of 2.3 GHz band propagation path loss characteristics by investigating the raw data gathered from the practical measurement is presented. Also we have performed field measurement in the frequency band over several types of building to obtain the penetration loss and diffraction loss. 2.3 GHz band propagation characteristics and corrected theoretical model for path loss prediction which was presented will be useful to the application such as prediction of path loss in the consideration of domestic environment, cell planning and optimization for new service systems.
{"title":"A study of 2.3 GHz bands propagation characteristic measured in Korea","authors":"H. Son, Geun-sik Bae, Hung-Soo Lee","doi":"10.1109/VETECS.2003.1207530","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1207530","url":null,"abstract":"It is being examined that 2.3 GHz frequency band is withdrawn and redistributed at the same new service for efficient use of the radio resource in South Korea. In this paper, analysis of 2.3 GHz band propagation path loss characteristics by investigating the raw data gathered from the practical measurement is presented. Also we have performed field measurement in the frequency band over several types of building to obtain the penetration loss and diffraction loss. 2.3 GHz band propagation characteristics and corrected theoretical model for path loss prediction which was presented will be useful to the application such as prediction of path loss in the consideration of domestic environment, cell planning and optimization for new service systems.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127405402","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 : 2003-04-22DOI: 10.1109/VETECS.2003.1207827
K. Hamaguchi, L. Hanzo
A combined scheme based on orthogonal frequency-division multiplexing and frequency-hopped multiple access (OFDM/FHMA) is proposed, in which the transmitted data is spread over both the time and frequency axes without expanding the bandwidth. The OFDM system advocated employs the Walsh-Hadamard transform (WHT) for spreading the data in the frequency domain and weights the received signal by the estimated signal-to-interference ratio (SIR) for the sake of reducing the effects of interference. The performance recorded, when communicating over an interference-limited channel suggests that the achievable BER improvement is as much an order of magnitude to that of an OFDM/FHMA scheme dispensing with WHT.
{"title":"Time-frequency spread OFDM/FHMA","authors":"K. Hamaguchi, L. Hanzo","doi":"10.1109/VETECS.2003.1207827","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1207827","url":null,"abstract":"A combined scheme based on orthogonal frequency-division multiplexing and frequency-hopped multiple access (OFDM/FHMA) is proposed, in which the transmitted data is spread over both the time and frequency axes without expanding the bandwidth. The OFDM system advocated employs the Walsh-Hadamard transform (WHT) for spreading the data in the frequency domain and weights the received signal by the estimated signal-to-interference ratio (SIR) for the sake of reducing the effects of interference. The performance recorded, when communicating over an interference-limited channel suggests that the achievable BER improvement is as much an order of magnitude to that of an OFDM/FHMA scheme dispensing with WHT.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114987330","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 : 2003-04-22DOI: 10.1109/VETECS.2003.1207142
T. Hwang, Ye Li
In this paper, we propose iterative methods to reconstruct the cycle prefix for coded single-carrier frequency-domain equalization (SC-FDE) systems that employ insufficient length of cycle prefix at the transmitter. Since the insertion of the cyclic prefix for SC-FDE systems decreases the bandwidth utilization efficiency as the channel's delay span increase, it is desirable to improve the bandwidth utilization efficiency by limiting the length of the cycle prefix. Two novel schemes for reconstructing the cycle prefix of coded SC-FDE systems are discussed: one employing the soft output of the soft output of the decoder and the other employing precoding. The performance of these schemes is shown by computer simulations.
{"title":"Iterative cyclic prefix reconstruction for coded single-carrier systems with frequency-domain equalization (SC-FDE)","authors":"T. Hwang, Ye Li","doi":"10.1109/VETECS.2003.1207142","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1207142","url":null,"abstract":"In this paper, we propose iterative methods to reconstruct the cycle prefix for coded single-carrier frequency-domain equalization (SC-FDE) systems that employ insufficient length of cycle prefix at the transmitter. Since the insertion of the cyclic prefix for SC-FDE systems decreases the bandwidth utilization efficiency as the channel's delay span increase, it is desirable to improve the bandwidth utilization efficiency by limiting the length of the cycle prefix. Two novel schemes for reconstructing the cycle prefix of coded SC-FDE systems are discussed: one employing the soft output of the soft output of the decoder and the other employing precoding. The performance of these schemes is shown by computer simulations.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123052239","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 : 2003-04-22DOI: 10.1109/VETECS.2003.1208895
M. Rossi, M. Zorzi
This work is a preliminary investigation on the effect of a controlled amount of retransmission on the residual higher layer packet error probability in a UMTS system. In this paper, we first characterize the delivery delay statistics regarding link layer service data units (SDUs) considering in order delivery. After this we propose a very simple heuristic able to approximate such statistics with great accuracy. This heuristic is well suited to being used in energy limited mobile terminals. In the final part of the paper, we investigate how this heuristic can be effectively used at the mobile terminal to dynamically choose the right amount of link layer retransmissions while respecting the delay constraints imposed on the higher layer flows. We quantitatively evaluate the maximum achievable gain when the optimum number of retransmissions is selected.
{"title":"An accurate heuristic approach for UMTS RLC delay statistics evaluation","authors":"M. Rossi, M. Zorzi","doi":"10.1109/VETECS.2003.1208895","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1208895","url":null,"abstract":"This work is a preliminary investigation on the effect of a controlled amount of retransmission on the residual higher layer packet error probability in a UMTS system. In this paper, we first characterize the delivery delay statistics regarding link layer service data units (SDUs) considering in order delivery. After this we propose a very simple heuristic able to approximate such statistics with great accuracy. This heuristic is well suited to being used in energy limited mobile terminals. In the final part of the paper, we investigate how this heuristic can be effectively used at the mobile terminal to dynamically choose the right amount of link layer retransmissions while respecting the delay constraints imposed on the higher layer flows. We quantitatively evaluate the maximum achievable gain when the optimum number of retransmissions is selected.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117126944","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 : 2003-04-22DOI: 10.1109/VETECS.2003.1207845
V. Leung, L. Larson, P. Gudem
An improved digital-IF transmitter architecture for W-CDMA mobile terminals is proposed. Based on the heterodyne design but without requiring any off-chip IF filter, the transmitter enjoys the advantages of a homodyne architecture (such as circuit simplicity low power consumption and high level of integration) while avoiding the performance problems associated with direct up-conversion. By implementing the quadrature modulation in the digital domain, and requiring only a single path of analog baseband circuits, inherently perfect I/Q matching and good EVM (error vector magnitude) performance can be achieved. The intermediate frequency (IF) is chosen to be a quarter of the clock rate for very simple and low power digital modulator design. The difficulties of on-chip IF filtering were greatly alleviated by (a) performing a careful frequency planning, and (b) employing a special-purpose DAC to produce high-order sin(x)/x rolloff. System level simulation demonstrates that spurious-emission requirements are met with virtually no dedicated reconstruction filter circuits. This architecture takes full advantage of CMOS technology scaling by employing digital processing to ease analog complexities.
{"title":"An improved digital-IF transmitter architecture for highly-integrated W-CDMA mobile terminals","authors":"V. Leung, L. Larson, P. Gudem","doi":"10.1109/VETECS.2003.1207845","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1207845","url":null,"abstract":"An improved digital-IF transmitter architecture for W-CDMA mobile terminals is proposed. Based on the heterodyne design but without requiring any off-chip IF filter, the transmitter enjoys the advantages of a homodyne architecture (such as circuit simplicity low power consumption and high level of integration) while avoiding the performance problems associated with direct up-conversion. By implementing the quadrature modulation in the digital domain, and requiring only a single path of analog baseband circuits, inherently perfect I/Q matching and good EVM (error vector magnitude) performance can be achieved. The intermediate frequency (IF) is chosen to be a quarter of the clock rate for very simple and low power digital modulator design. The difficulties of on-chip IF filtering were greatly alleviated by (a) performing a careful frequency planning, and (b) employing a special-purpose DAC to produce high-order sin(x)/x rolloff. System level simulation demonstrates that spurious-emission requirements are met with virtually no dedicated reconstruction filter circuits. This architecture takes full advantage of CMOS technology scaling by employing digital processing to ease analog complexities.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127165035","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 : 2003-04-22DOI: 10.1109/VETECS.2003.1207852
S. Ng, L. Hanzo
Space-time block coded (STBC) in-phase/quadrature-phase (IQ)-interleaved trellis coded modulation (TCM) and turbo TCM (TTCM) schemes are proposed, which are capable of quadrupling the achievable density order of the conventional symbol-interleaved TCM and TTCM schemes, when two transmit antennas are employed. The increased diversity order of the proposed schemes provides significant additional coding gains when communicating over non-dispersive Rayleigh fading channels, which is achieved without compromising the coding gain attainable over Gaussian channels. Bit-interleaved coded modulation (BICM) as well as iteratively decoded BICM (BICM-ID) is also incorporated into the proposed system and their performance is compared to that of TCM and TTCM.
{"title":"Space-time block coded IQ-interleaved joint coding and modulation for AWGN and Rayleigh fading channels","authors":"S. Ng, L. Hanzo","doi":"10.1109/VETECS.2003.1207852","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1207852","url":null,"abstract":"Space-time block coded (STBC) in-phase/quadrature-phase (IQ)-interleaved trellis coded modulation (TCM) and turbo TCM (TTCM) schemes are proposed, which are capable of quadrupling the achievable density order of the conventional symbol-interleaved TCM and TTCM schemes, when two transmit antennas are employed. The increased diversity order of the proposed schemes provides significant additional coding gains when communicating over non-dispersive Rayleigh fading channels, which is achieved without compromising the coding gain attainable over Gaussian channels. Bit-interleaved coded modulation (BICM) as well as iteratively decoded BICM (BICM-ID) is also incorporated into the proposed system and their performance is compared to that of TCM and TTCM.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127465648","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 : 2003-04-22DOI: 10.1109/VETECS.2003.1207743
Jia Hou, M. Lee, Ju Yong Park
A simple generalized correlation canceling decoding algorithm for space time block codes is introduced in this paper. It brings the linear algebra correlation canceling technique to estimate the correlating symbols both in non-orthogonal space time block codes and orthogonal cases. In addition, its simple structure can be easily generalized and implemented for realization.
{"title":"Simple correlation canceling algorithm for space time block codes","authors":"Jia Hou, M. Lee, Ju Yong Park","doi":"10.1109/VETECS.2003.1207743","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1207743","url":null,"abstract":"A simple generalized correlation canceling decoding algorithm for space time block codes is introduced in this paper. It brings the linear algebra correlation canceling technique to estimate the correlating symbols both in non-orthogonal space time block codes and orthogonal cases. In addition, its simple structure can be easily generalized and implemented for realization.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125899891","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 : 2003-04-22DOI: 10.1109/VETECS.2003.1207539
Lin Yang, Mohamed-Slim Alouini
This paper derives the average level crossing rate (LCR) and the average outage duration (AOD) of selection combining (SC) over correlated and/or unbalanced channels. More specifically, it presents a general approach for the analysis of such systems operating over correlated Rayleigh, Rician, and/or Nakagami fading channels. The general approach is then applied to obtain generic closed-form expressions for the LCR and AOD of dual-branch SC in a correlated Rayleigh and Nakagami fading environment. The results obtained as special cases of the offered generic closed-form expressions are compared to those previously reported in the literature. Finally, some numerical examples comparing the LCR and AOD of SC with various value of fading correlation, average fading power unbalance, and Nakagami parameter are provided and discussed.
{"title":"An exact analysis of the impact of fading correlation on the average level crossing rate and average outage duration of selection combining","authors":"Lin Yang, Mohamed-Slim Alouini","doi":"10.1109/VETECS.2003.1207539","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1207539","url":null,"abstract":"This paper derives the average level crossing rate (LCR) and the average outage duration (AOD) of selection combining (SC) over correlated and/or unbalanced channels. More specifically, it presents a general approach for the analysis of such systems operating over correlated Rayleigh, Rician, and/or Nakagami fading channels. The general approach is then applied to obtain generic closed-form expressions for the LCR and AOD of dual-branch SC in a correlated Rayleigh and Nakagami fading environment. The results obtained as special cases of the offered generic closed-form expressions are compared to those previously reported in the literature. Finally, some numerical examples comparing the LCR and AOD of SC with various value of fading correlation, average fading power unbalance, and Nakagami parameter are provided and discussed.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126139879","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 : 2003-04-22DOI: 10.1109/VETECS.2003.1207526
M. Skold, Yeongyoon Choi, J. Nilsson
In this paper we present a novel approach for evaluating the routing efficiency of clustered architectures, as compared to flat ones in mobile scenarios. For multihop ad hoc networks there have been much research done on clustered architectures due to their advantages, such as the spatial reuse of resources, the easier update of hierarchical topology and the smaller overheads on routing procedures. However, the efficiency of using a clustered architecture depends on many factors such as the network size, how the clusters are formed, type of traffic, connection data rates, network connectivity and topology changes due to in particular node mobility. Our results show that the clustered architecture needs to be very carefully designed in order to be more efficient than a flat architecture for small to medium sized networks of up to 400 nodes. That is, a clusterhead needs to have good knowledge of the links in its cluster such a good route through the cluster can be selected.
{"title":"An analysis of mobile radio ad hoc networks using clustered architectures","authors":"M. Skold, Yeongyoon Choi, J. Nilsson","doi":"10.1109/VETECS.2003.1207526","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1207526","url":null,"abstract":"In this paper we present a novel approach for evaluating the routing efficiency of clustered architectures, as compared to flat ones in mobile scenarios. For multihop ad hoc networks there have been much research done on clustered architectures due to their advantages, such as the spatial reuse of resources, the easier update of hierarchical topology and the smaller overheads on routing procedures. However, the efficiency of using a clustered architecture depends on many factors such as the network size, how the clusters are formed, type of traffic, connection data rates, network connectivity and topology changes due to in particular node mobility. Our results show that the clustered architecture needs to be very carefully designed in order to be more efficient than a flat architecture for small to medium sized networks of up to 400 nodes. That is, a clusterhead needs to have good knowledge of the links in its cluster such a good route through the cluster can be selected.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125348988","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：