Pub Date : 2006-09-18DOI: 10.1109/GLOCOM.2003.1258671
S. Leong, Jingxian Wu, J. Olivier, Chengshan Xiao
The channel estimation and equalization for EDGE system with time-varying and frequency-selective fading channels are discussed. It is shown that the fast fading channel during a selected slot in the EDGE system can be modeled as a linear function of time, and a linear least-squares algorithm is proposed to estimate the fading channel. For typical channel profiles of the EDGE system, the channel impulse response is not in its minimum phase form, thus cannot be directly used in computationally efficient equalizers, such as delayed decision feedback sequence estimation or reduced state sequence estimation. To overcome this problem, a Cholesky decomposition-based method is introduced to transform the estimated channel impulse response into its minimum phase form. The simulation results show that the proposed algorithms can effectively combat the time-varying and frequency-selective channel fading with Doppler frequency being in a wide range up to 300 Hz.
{"title":"Fast time-varying dispersive channel estimation and equalization for 8-PSK cellular system","authors":"S. Leong, Jingxian Wu, J. Olivier, Chengshan Xiao","doi":"10.1109/GLOCOM.2003.1258671","DOIUrl":"https://doi.org/10.1109/GLOCOM.2003.1258671","url":null,"abstract":"The channel estimation and equalization for EDGE system with time-varying and frequency-selective fading channels are discussed. It is shown that the fast fading channel during a selected slot in the EDGE system can be modeled as a linear function of time, and a linear least-squares algorithm is proposed to estimate the fading channel. For typical channel profiles of the EDGE system, the channel impulse response is not in its minimum phase form, thus cannot be directly used in computationally efficient equalizers, such as delayed decision feedback sequence estimation or reduced state sequence estimation. To overcome this problem, a Cholesky decomposition-based method is introduced to transform the estimated channel impulse response into its minimum phase form. The simulation results show that the proposed algorithms can effectively combat the time-varying and frequency-selective channel fading with Doppler frequency being in a wide range up to 300 Hz.","PeriodicalId":301154,"journal":{"name":"GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122182154","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 : 2005-07-01DOI: 10.1109/GLOCOM.2003.1258389
Jianghong Luo, R. Yates, P. Spasojevic
The service outage based allocation problem explores variable rate transmission schemes and combines the concepts of ergodic capacity and capacity versus outage for fading channels. A service outage occurs when the transmission rate is below a given basic rate r/sub o/. The allocation problem is to maximize the expected rate subject to the average power constraint and the constraint that the outage probability is less than /spl epsiv/. A general class of probabilistic power allocation schemes is considered in this problem. In an M-parallel fading channel model, the optimum power allocation scheme is derived and is shown to be deterministic except at channel states of a boundary set. The resulting service outage average rate is between the outage capacity times 1-/spl epsiv/ and the ergodic capacity.
{"title":"Service outage based power and rate allocation for parallel fading channels","authors":"Jianghong Luo, R. Yates, P. Spasojevic","doi":"10.1109/GLOCOM.2003.1258389","DOIUrl":"https://doi.org/10.1109/GLOCOM.2003.1258389","url":null,"abstract":"The service outage based allocation problem explores variable rate transmission schemes and combines the concepts of ergodic capacity and capacity versus outage for fading channels. A service outage occurs when the transmission rate is below a given basic rate r/sub o/. The allocation problem is to maximize the expected rate subject to the average power constraint and the constraint that the outage probability is less than /spl epsiv/. A general class of probabilistic power allocation schemes is considered in this problem. In an M-parallel fading channel model, the optimum power allocation scheme is derived and is shown to be deterministic except at channel states of a boundary set. The resulting service outage average rate is between the outage capacity times 1-/spl epsiv/ and the ergodic capacity.","PeriodicalId":301154,"journal":{"name":"GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489)","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124019342","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 : 2004-03-21DOI: 10.1109/GLOCOM.2003.1258436
L. Fregni, F. Muratori, P. Greco, G. Vitetta, F. Pancaldi
In this paper novel reduced complexity statistical models for the representation of wide sense stationary-uncorrelated scattering directional wireless channels affected by Rayleigh fading are developed. Their derivation is based on the so-called Gaussian quadrature rule approach illustrated in E Chiavaccini et al. (2001). for non directional channels. Numerical results evidence that the proposed models can provide a simple and accurate stochastic representation of directional fading channels.
{"title":"GQR models for directional wireless channels","authors":"L. Fregni, F. Muratori, P. Greco, G. Vitetta, F. Pancaldi","doi":"10.1109/GLOCOM.2003.1258436","DOIUrl":"https://doi.org/10.1109/GLOCOM.2003.1258436","url":null,"abstract":"In this paper novel reduced complexity statistical models for the representation of wide sense stationary-uncorrelated scattering directional wireless channels affected by Rayleigh fading are developed. Their derivation is based on the so-called Gaussian quadrature rule approach illustrated in E Chiavaccini et al. (2001). for non directional channels. Numerical results evidence that the proposed models can provide a simple and accurate stochastic representation of directional fading channels.","PeriodicalId":301154,"journal":{"name":"GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489)","volume":"2016 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114456623","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 : 2003-12-01DOI: 10.1109/GLOCOM.2003.1258306
Guocong Song, Ye Li
This paper investigates efficient and fair resource allocation, which is realized by using utility functions to measure the quality of service of users, in multiuser orthogonal frequency division multiplexing (OFDM) networks. To achieve the optimal resource allocation, we develop a series of efficient utility-based resource allocation algorithms that cover many conditions, including various dynamic subcarrier assignment and power allocation algorithms. The simulation results show that utility functions, together with dynamic subcarrier allocation, adaptive power allocation, and low-pass time window, can obtain multiuser, frequency, and time diversity, and significantly improve network efficiency as well as fairness.
{"title":"Adaptive resource allocation based on utility optimization in OFDM","authors":"Guocong Song, Ye Li","doi":"10.1109/GLOCOM.2003.1258306","DOIUrl":"https://doi.org/10.1109/GLOCOM.2003.1258306","url":null,"abstract":"This paper investigates efficient and fair resource allocation, which is realized by using utility functions to measure the quality of service of users, in multiuser orthogonal frequency division multiplexing (OFDM) networks. To achieve the optimal resource allocation, we develop a series of efficient utility-based resource allocation algorithms that cover many conditions, including various dynamic subcarrier assignment and power allocation algorithms. The simulation results show that utility functions, together with dynamic subcarrier allocation, adaptive power allocation, and low-pass time window, can obtain multiuser, frequency, and time diversity, and significantly improve network efficiency as well as fairness.","PeriodicalId":301154,"journal":{"name":"GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489)","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115161279","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 : 2003-12-01DOI: 10.1109/GLOCOM.2003.1258525
Dong In Kim
A novel two-dimensional diversity combining is proposed for the uplink in a single cell that employs multidimensional multicode DS-CDMA signaling and two receive antennas. First, the signaling is combined with preceding to obtain a constant envelope signal that is suitable for the uplink, and the resulting error detection is applied to the diversity combining. Based on the error detection, an adaptive selection combining/maximal-ratio combining (SC/MRC) is performed for which initial data detection is made by the SC to avoid the combining loss of the very noisy paths. Further, this adaptive SC/MRC is generalized to maximize the diversity gain over the MRC, offered by the error detection capability.
{"title":"Adaptive selection/maximal-ratio combining for multidimensional multicode DS-CDMA with precoding","authors":"Dong In Kim","doi":"10.1109/GLOCOM.2003.1258525","DOIUrl":"https://doi.org/10.1109/GLOCOM.2003.1258525","url":null,"abstract":"A novel two-dimensional diversity combining is proposed for the uplink in a single cell that employs multidimensional multicode DS-CDMA signaling and two receive antennas. First, the signaling is combined with preceding to obtain a constant envelope signal that is suitable for the uplink, and the resulting error detection is applied to the diversity combining. Based on the error detection, an adaptive selection combining/maximal-ratio combining (SC/MRC) is performed for which initial data detection is made by the SC to avoid the combining loss of the very noisy paths. Further, this adaptive SC/MRC is generalized to maximize the diversity gain over the MRC, offered by the error detection capability.","PeriodicalId":301154,"journal":{"name":"GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115300369","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 : 2003-12-01DOI: 10.1109/GLOCOM.2003.1258490
R. Bobba, Laurent Eschenauer, V. Gligor, W. Arbaugh
To date, most solutions proposed for secure routing in mobile ad-hoc networks (MANETs), assume that secure associations between pairs of nodes can be established on-line; e.g., by a trusted third party, by distributed trust establishment. However, establishing such security associations, with or without trusted third parties, requires reliance on routing layer security. In this paper, we eliminate this apparent cyclic dependency between security services and secure routing in MANETs and show how to bootstrap security for the routing layer. We use the notion of statistically unique and cryptographically verifiable (SUCV) identifiers to implement a secure binding between IP addresses and keys that is independent of any trusted security service. We illustrate our solution with the dynamic source routing (DSR) protocol and compare it with other solutions for secure routing.
{"title":"Bootstrapping security associations for routing in mobile ad-hoc networks","authors":"R. Bobba, Laurent Eschenauer, V. Gligor, W. Arbaugh","doi":"10.1109/GLOCOM.2003.1258490","DOIUrl":"https://doi.org/10.1109/GLOCOM.2003.1258490","url":null,"abstract":"To date, most solutions proposed for secure routing in mobile ad-hoc networks (MANETs), assume that secure associations between pairs of nodes can be established on-line; e.g., by a trusted third party, by distributed trust establishment. However, establishing such security associations, with or without trusted third parties, requires reliance on routing layer security. In this paper, we eliminate this apparent cyclic dependency between security services and secure routing in MANETs and show how to bootstrap security for the routing layer. We use the notion of statistically unique and cryptographically verifiable (SUCV) identifiers to implement a secure binding between IP addresses and keys that is independent of any trusted security service. We illustrate our solution with the dynamic source routing (DSR) protocol and compare it with other solutions for secure routing.","PeriodicalId":301154,"journal":{"name":"GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115653009","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 : 2003-12-01DOI: 10.1109/GLOCOM.2003.1258268
Dong In Kim, E. Hossain, V. Bhargava
This paper addresses the problem of dynamic rate and power adaptation for forward link data transmission using high-order modulation and multicode formats in cellular wideband code division multiple access (WCDMA) networks. A novel framework for dynamic joint adaptation of modulation order, number of code channels (hence transmission rate) and transmission power is proposed for downlink data transmission in a cellular WCDMA system where the different users have similar frame error rate (FER) requirements. Based on a general downlink signal-to-interference ratio (SIR) model, the problem of optimal dynamic rate and power adaptation is formulated, for which the rate and power allocation can be found by an exhaustive search. Two heuristic-based dynamic rate and power allocation schemes are proposed. Performance of dynamic joint rate and power adaptation under the proposed frame-work is evaluated under random micro-mobility model using computer simulations.
{"title":"Dynamic rate and power adaptation for forward link transmission using high-order modulation and multicode formats in cellular WCDMA networks","authors":"Dong In Kim, E. Hossain, V. Bhargava","doi":"10.1109/GLOCOM.2003.1258268","DOIUrl":"https://doi.org/10.1109/GLOCOM.2003.1258268","url":null,"abstract":"This paper addresses the problem of dynamic rate and power adaptation for forward link data transmission using high-order modulation and multicode formats in cellular wideband code division multiple access (WCDMA) networks. A novel framework for dynamic joint adaptation of modulation order, number of code channels (hence transmission rate) and transmission power is proposed for downlink data transmission in a cellular WCDMA system where the different users have similar frame error rate (FER) requirements. Based on a general downlink signal-to-interference ratio (SIR) model, the problem of optimal dynamic rate and power adaptation is formulated, for which the rate and power allocation can be found by an exhaustive search. Two heuristic-based dynamic rate and power allocation schemes are proposed. Performance of dynamic joint rate and power adaptation under the proposed frame-work is evaluated under random micro-mobility model using computer simulations.","PeriodicalId":301154,"journal":{"name":"GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124399733","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 : 2003-12-01DOI: 10.1109/GLOCOM.2003.1258368
Ronghong Mo, Y. Chew
An adaptive SNR-priority-based channel allocation scheme over multiple access fading channel is proposed. The performance of this scheme is a compromise between the conventional TDMA scheme which has short channel access waiting time but poor spectral efficiency, and the best SNR user transmitting scheme which has better bandwidth efficiency but longer channel access waiting time. The capacity achieved by this scheme is studied and compared with the conventional rate adaptive TDMA systems. The operation of this scheme requires channel estimation which is performed at the frame period for all N mobiles. For the SNR-priority -based system, the frame period is divided into K slots and only K mobiles that observe the first K best channel conditions are assigned to transmit. By assuming that only best-effort traffic is served, the channel capacity and the system throughput of the SNR-priority-based TDMA system achieved with rate adaptive MQAM modulation technique are studied. The average channel inter-access time for such a system is also studied through simulation.
{"title":"Capacity and throughput for transmission over flat fading channels employing SNR-priority-based channel allocation scheme","authors":"Ronghong Mo, Y. Chew","doi":"10.1109/GLOCOM.2003.1258368","DOIUrl":"https://doi.org/10.1109/GLOCOM.2003.1258368","url":null,"abstract":"An adaptive SNR-priority-based channel allocation scheme over multiple access fading channel is proposed. The performance of this scheme is a compromise between the conventional TDMA scheme which has short channel access waiting time but poor spectral efficiency, and the best SNR user transmitting scheme which has better bandwidth efficiency but longer channel access waiting time. The capacity achieved by this scheme is studied and compared with the conventional rate adaptive TDMA systems. The operation of this scheme requires channel estimation which is performed at the frame period for all N mobiles. For the SNR-priority -based system, the frame period is divided into K slots and only K mobiles that observe the first K best channel conditions are assigned to transmit. By assuming that only best-effort traffic is served, the channel capacity and the system throughput of the SNR-priority-based TDMA system achieved with rate adaptive MQAM modulation technique are studied. The average channel inter-access time for such a system is also studied through simulation.","PeriodicalId":301154,"journal":{"name":"GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489)","volume":"178 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124403080","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 : 2003-12-01DOI: 10.1109/GLOCOM.2003.1258271
J. Bellorado, S. Ghassemzadeh, L. Greenstein, T. Sveinsson, V. Tarokh
In this study we provide a physical layer based analysis of the coexistence issues of ultra-wideband (UWB) with other devices in the same spectrum. Specifically, we have focused on the UWB interference to and from devices using the wireless local area network (WLAN) standard IEEE 802.11a. Our results indicate that a UWB interferer operating at the peak allowable power density induces minimal interference into such WLAN devices in line-of sight (LOS) scenarios, even at close range. However, in the non-LOS (NLOS) case, a UWB interferer can severely affect the data-rate sustainable by 802.11a systems. Moreover, 802.11a interference into UWB systems is shown to reduce the signal-to-interference ratio (SIR) by as much as 36 dB when the interferer is within LOS of the UWB receiver.
{"title":"Coexistence of ultra-wideband systems with IEEE-802.11 a wireless LANs","authors":"J. Bellorado, S. Ghassemzadeh, L. Greenstein, T. Sveinsson, V. Tarokh","doi":"10.1109/GLOCOM.2003.1258271","DOIUrl":"https://doi.org/10.1109/GLOCOM.2003.1258271","url":null,"abstract":"In this study we provide a physical layer based analysis of the coexistence issues of ultra-wideband (UWB) with other devices in the same spectrum. Specifically, we have focused on the UWB interference to and from devices using the wireless local area network (WLAN) standard IEEE 802.11a. Our results indicate that a UWB interferer operating at the peak allowable power density induces minimal interference into such WLAN devices in line-of sight (LOS) scenarios, even at close range. However, in the non-LOS (NLOS) case, a UWB interferer can severely affect the data-rate sustainable by 802.11a systems. Moreover, 802.11a interference into UWB systems is shown to reduce the signal-to-interference ratio (SIR) by as much as 36 dB when the interferer is within LOS of the UWB receiver.","PeriodicalId":301154,"journal":{"name":"GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489)","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123084692","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 : 2003-12-01DOI: 10.1109/GLOCOM.2003.1258446
Szu-Chi Wang, David S. L. Wei, S. Kuo
In this paper, we present a localized algorithm for constructing power efficient topology for wireless ad hoc networks. Each mobile node determines its own transmission power based only on local information. The proposed algorithm first constructs the constrained Gabriel graph from the given unit disk graph and then reduces the total transmission power by allowing each node individually excises some replaceable links. The constructed topology is sparse, has a constant bounded power stretch factor, and the total transmission power is lower than those obtained from other proposed algorithms. In addition, compared with others, our algorithm requires lower time complexity to generate a solution, and can thus further save the energy for each mobile node. We demonstrate the performance improvements of our algorithm through simulations.
{"title":"A topology control algorithm for constructing power efficient wireless ad hoc networks","authors":"Szu-Chi Wang, David S. L. Wei, S. Kuo","doi":"10.1109/GLOCOM.2003.1258446","DOIUrl":"https://doi.org/10.1109/GLOCOM.2003.1258446","url":null,"abstract":"In this paper, we present a localized algorithm for constructing power efficient topology for wireless ad hoc networks. Each mobile node determines its own transmission power based only on local information. The proposed algorithm first constructs the constrained Gabriel graph from the given unit disk graph and then reduces the total transmission power by allowing each node individually excises some replaceable links. The constructed topology is sparse, has a constant bounded power stretch factor, and the total transmission power is lower than those obtained from other proposed algorithms. In addition, compared with others, our algorithm requires lower time complexity to generate a solution, and can thus further save the energy for each mobile node. We demonstrate the performance improvements of our algorithm through simulations.","PeriodicalId":301154,"journal":{"name":"GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116975447","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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