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2002 International Zurich Seminar on Broadband Communications Access - Transmission - Networking (Cat. No.02TH8599)最新文献

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Optimal quadratic non-assisted parameter estimation for digital synchronisation 数字同步的最优二次非辅助参数估计
2002 International Zurich Seminar on Broadband Communications Access - Transmission - Networking (Cat. No.02TH8599) Pub Date : 2002-08-07 DOI: 10.1109/IZSBC.2002.991789
J. Villares, G. Vázquez
{"title":"Optimal quadratic non-assisted parameter estimation for digital synchronisation","authors":"J. Villares, G. Vázquez","doi":"10.1109/IZSBC.2002.991789","DOIUrl":"https://doi.org/10.1109/IZSBC.2002.991789","url":null,"abstract":"This paper deals with the optimal design of quadratic non-data-aided (NDA) open- and closed-loop estimators. The new approach supplies the best quadratic unbiased estimator (BQUE), i.e., that one with the minimum variance, without the need of assuming a given statistic for the nuisance parameters, that is, avoiding the common adoption of the Gaussian assumption, which does not apply in digital communications. Alternatively, if the unbiased constraint is relaxed, a Bayesian open-loop estimator is presented and its performance compared with the open-loop BQUE solution. On the other hand, the closed-loop BQUE is developed, showing that it outperforms the well-known \"ad hoc\" Gaussian stochastic maximum likelihood (GSML) scheme for short observation windows, that is, for low-complexity implementations, only converging to the Gaussian unconditional Cramer-Rao bound UGCRB asymptotically. Afterwards, the BQUE deduction is applied to obtain robust NDA estimators of the signal parameters in the presence of a frequency-selective channel. Finally, the quadratic analysis is naturally extended to higher-order techniques which exhibit a better performance for high SNR.","PeriodicalId":336991,"journal":{"name":"2002 International Zurich Seminar on Broadband Communications Access - Transmission - Networking (Cat. No.02TH8599)","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127372984","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}
引用次数: 2
Microwave path-loss characteristics in an urban area with base station antenna on top of a tall building 高层建筑顶部基站天线的城市微波路径损耗特性
2002 International Zurich Seminar on Broadband Communications Access - Transmission - Networking (Cat. No.02TH8599) Pub Date : 2002-08-07 DOI: 10.1109/IZSBC.2002.991774
K. Sakawa, H. Masui, M. Ishii, H. Shimizu, T. Kobayashi
{"title":"Microwave path-loss characteristics in an urban area with base station antenna on top of a tall building","authors":"K. Sakawa, H. Masui, M. Ishii, H. Shimizu, T. Kobayashi","doi":"10.1109/IZSBC.2002.991774","DOIUrl":"https://doi.org/10.1109/IZSBC.2002.991774","url":null,"abstract":"Much research has been reported on the microwave band as a powerful means of achieving 4th-generation mobile communications systems. The focus of this research, however, has been propagation characteristics under the assumption of low antenna height for base stations in a microcell environment. This paper, in contrast, clarifies microwave path-loss characteristics in an environment where the height of the transmitting base-station antenna is higher than that of surrounding buildings. Path-loss characteristics (attenuation coefficient, corner loss, relative loss, and standard deviation) in a non-line-of-sight (NLOS) environment with high antenna height were found to be quite different than those of a conventional low-antenna-height environment. This is because the propagation mechanism of primary waves is significantly altered by the change in antenna height. It was found, in particular, that rooftop diffracted waves come to dominate in a high-antenna-height, NLOS environment.","PeriodicalId":336991,"journal":{"name":"2002 International Zurich Seminar on Broadband Communications Access - Transmission - Networking (Cat. No.02TH8599)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122518482","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}
引用次数: 9
European research in mobile and personal communications - perspectives for the future 欧洲在移动和个人通信方面的研究——展望未来
2002 International Zurich Seminar on Broadband Communications Access - Transmission - Networking (Cat. No.02TH8599) Pub Date : 2002-08-07 DOI: 10.1109/IZSBC.2002.991741
J. Pereira
{"title":"European research in mobile and personal communications - perspectives for the future","authors":"J. Pereira","doi":"10.1109/IZSBC.2002.991741","DOIUrl":"https://doi.org/10.1109/IZSBC.2002.991741","url":null,"abstract":"The achievements of European R&D, in particular in the area of mobile and personal communications, are briefly reviewed. The contributions to standardisation, both at European (ETSI) and global (ITU) level, are emphasised, whilst making the case for the critical importance of the regulatory issues that make or break a market (availability of spectrum, licensing, pan-European services etc). In light of the upcoming Sixth Framework Program (2003-2006), we introduce the themes and priorities identified thus far and discuss briefly the mechanisms under consideration for participation in EU-funded R&D.","PeriodicalId":336991,"journal":{"name":"2002 International Zurich Seminar on Broadband Communications Access - Transmission - Networking (Cat. No.02TH8599)","volume":"243 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121456681","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}
引用次数: 0
The effect of initial on-state probability on effective capacity 初始导通概率对有效容量的影响
2002 International Zurich Seminar on Broadband Communications Access - Transmission - Networking (Cat. No.02TH8599) Pub Date : 2002-08-07 DOI: 10.1109/IZSBC.2002.991757
C. Amo-Quarm, K. Sohraby
{"title":"The effect of initial on-state probability on effective capacity","authors":"C. Amo-Quarm, K. Sohraby","doi":"10.1109/IZSBC.2002.991757","DOIUrl":"https://doi.org/10.1109/IZSBC.2002.991757","url":null,"abstract":"The effective bandwidth as a function of auto- and cross-correlation in several moments of video clips demonstrates interesting behavior. In several cases of analysis, it is observed that depending on the parameters of the source, the effective bandwidth as a function of correlation, may be below or above the steady state value in short time interval. We focus on such behavior and try to explain the implications.","PeriodicalId":336991,"journal":{"name":"2002 International Zurich Seminar on Broadband Communications Access - Transmission - Networking (Cat. No.02TH8599)","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129375613","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}
引用次数: 1
Design of OFDM systems for frequency-selective and time-variant channels 选频时变信道OFDM系统的设计
2002 International Zurich Seminar on Broadband Communications Access - Transmission - Networking (Cat. No.02TH8599) Pub Date : 2002-08-07 DOI: 10.1109/IZSBC.2002.991782
A. Hutter
{"title":"Design of OFDM systems for frequency-selective and time-variant channels","authors":"A. Hutter","doi":"10.1109/IZSBC.2002.991782","DOIUrl":"https://doi.org/10.1109/IZSBC.2002.991782","url":null,"abstract":"We show that frequency-selectivity and time-variance represent adverse constraints for the design of wireless OFDM systems. This observation is important since OFDM is a promising candidate for the realisation of broadband wireless systems, which by definition transmit over frequency-selective and time-variant channels. We present a convenient design criterion for the OFDM symbol duration. The criterion is relating the two basic channel parameters, the maximum excess delay time and the maximum Doppler frequency, with two design parameters reflecting the bandwidth efficiency and the robustness of the system. The introduction of the latter two parameters allows the efficient design of OFDM systems by providing information on the system reserves. Furthermore, we show how the use of multiple antenna arrays exploiting spatial diversity can be incorporated in the system design.","PeriodicalId":336991,"journal":{"name":"2002 International Zurich Seminar on Broadband Communications Access - Transmission - Networking (Cat. No.02TH8599)","volume":"259 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116048120","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}
引用次数: 8
An advanced receiver with interference cancellation for broadband cable networks 一种先进的宽带有线网络干扰消除接收器
2002 International Zurich Seminar on Broadband Communications Access - Transmission - Networking (Cat. No.02TH8599) Pub Date : 2002-08-07 DOI: 10.1109/IZSBC.2002.991763
A. Popper, F. Buda, H. Sari
{"title":"An advanced receiver with interference cancellation for broadband cable networks","authors":"A. Popper, F. Buda, H. Sari","doi":"10.1109/IZSBC.2002.991763","DOIUrl":"https://doi.org/10.1109/IZSBC.2002.991763","url":null,"abstract":"We present an advanced receiver with adaptive equalization and narrowband interference cancellation for the upstream channel in broadband cable networks. The interference canceller is based on noise prediction. The simulation results indicate that the presented receiver makes it possible to transmit a QPSK signal in the presence of 3 interferers with an individual power of -10 dBc with a SNR degradation of 1.8 dB only. For 16-QAM, the SNR degradation is 2.1 dB with 3 interferers at -15 dBc. We study the problems associated with the joint adaptation of the equalizer and the interference canceller and we describe an efficient algorithm that ensures both stability and fast convergence.","PeriodicalId":336991,"journal":{"name":"2002 International Zurich Seminar on Broadband Communications Access - Transmission - Networking (Cat. No.02TH8599)","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125530000","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}
引用次数: 1
Hybrid beamforming: reduced eigen beamforming on beam signals 混合波束形成:波束信号的降低本征波束形成
2002 International Zurich Seminar on Broadband Communications Access - Transmission - Networking (Cat. No.02TH8599) Pub Date : 2002-08-07 DOI: 10.1109/IZSBC.2002.991749
I. Viering, T. Frey, G. Schnabl
{"title":"Hybrid beamforming: reduced eigen beamforming on beam signals","authors":"I. Viering, T. Frey, G. Schnabl","doi":"10.1109/IZSBC.2002.991749","DOIUrl":"https://doi.org/10.1109/IZSBC.2002.991749","url":null,"abstract":"A hybrid beamforming technique for multiple antenna receivers is introduced. It is a combination of a simple fixed beam method and the adaptive eigen beamforming algorithm. This two-stage solution allows for a user-specific scalable trade-off between performance and complexity, depending on the interference scenario. Furthermore, the dimensions of the eigen beamforming stage can be reduced with only slight performance degradation. The hybrid scheme is compared with the stand-alone algorithms in different two-user scenarios under ideal as well as under more realistic assumptions. It is shown, that in many scenarios the fixed beamforming stage is sufficient. In more severe interference scenarios, the hybrid techniques approach the performance of the eigen beamformer with less complexity.","PeriodicalId":336991,"journal":{"name":"2002 International Zurich Seminar on Broadband Communications Access - Transmission - Networking (Cat. No.02TH8599)","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122216713","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}
引用次数: 4
Tomlinson-Harashima precoding in space-time transmission for low-rate backward channel 低速率反向信道空时传输中的Tomlinson-Harashima预编码
2002 International Zurich Seminar on Broadband Communications Access - Transmission - Networking (Cat. No.02TH8599) Pub Date : 2002-08-07 DOI: 10.1109/IZSBC.2002.991747
Robert F. H. Fischer, C. Windpassinger, Alexander Lampe, Johannes B. Huber
{"title":"Tomlinson-Harashima precoding in space-time transmission for low-rate backward channel","authors":"Robert F. H. Fischer, C. Windpassinger, Alexander Lampe, Johannes B. Huber","doi":"10.1109/IZSBC.2002.991747","DOIUrl":"https://doi.org/10.1109/IZSBC.2002.991747","url":null,"abstract":"In this paper, Tomlinson-Harashima precoding, a nonlinear pre-equalization technique, is proposed for transmission over multiple-input/multiple-output channels. Instead of equalizing intersymbol interference (temporal equalization) here spatial equalization, i.e., equalization of multi-user interference is performed. If only a low-rate backward channel is available for communicating channel state information back from the receiver to the transmitter, a compromise precoder setting, calculated from (medium-term) average channel knowledge in combination with linear residual equalization at the receiver side is proposed. Compared to an optimal adjustment of the precoder, i.e., perfect channel state information at the transmitter, only small losses have to be accepted.","PeriodicalId":336991,"journal":{"name":"2002 International Zurich Seminar on Broadband Communications Access - Transmission - Networking (Cat. No.02TH8599)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116474081","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}
引用次数: 92
Bandwidth allocation for non-responsive flows with active queue management 具有活动队列管理的非响应流的带宽分配
2002 International Zurich Seminar on Broadband Communications Access - Transmission - Networking (Cat. No.02TH8599) Pub Date : 2002-08-07 DOI: 10.1109/IZSBC.2002.991753
Ed Bowen, Clark Jeffries
{"title":"Bandwidth allocation for non-responsive flows with active queue management","authors":"Ed Bowen, Clark Jeffries","doi":"10.1109/IZSBC.2002.991753","DOIUrl":"https://doi.org/10.1109/IZSBC.2002.991753","url":null,"abstract":"This paper addresses the problem of configuring active queue management systems (e.g. WRED and RIO) for service level specifications in internetworks. In particular, we focus on assured forwarding (AF) for non-responsive flows in differentiated services networks. The difficulty is to determine the correct queue level thresholds that will result in correct drop rates for various AF precedence levels under any combination of offered loads. A new active queue management scheme based on a control algorithm is proposed that senses not only queue levels but also rates of queue levels changes and per flow bit rates to converge automatically to an optimal set of transmit fractions. The scheme has been implemented and tested on a network processor. Results show that the new active queue management scheme protects assured aggregated flow rates during periods of congestion. For non-responsive traffic the buffer occupancy level remains low during 250% offered load.","PeriodicalId":336991,"journal":{"name":"2002 International Zurich Seminar on Broadband Communications Access - Transmission - Networking (Cat. No.02TH8599)","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116699549","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}
引用次数: 17
Transmit antenna diversity for OFDM-based W-LANs with a priori channel state information 具有先验信道状态信息的基于ofdm的w - lan发射天线分集
2002 International Zurich Seminar on Broadband Communications Access - Transmission - Networking (Cat. No.02TH8599) Pub Date : 2002-08-07 DOI: 10.1109/IZSBC.2002.991750
A. Barreto
{"title":"Transmit antenna diversity for OFDM-based W-LANs with a priori channel state information","authors":"A. Barreto","doi":"10.1109/IZSBC.2002.991750","DOIUrl":"https://doi.org/10.1109/IZSBC.2002.991750","url":null,"abstract":"OFDM-based W-LAN systems employ TDD and are typically used in nearly static environments, for which it is reasonable to assume that channel state information can be acquired before transmission. If multiple antennas are provided at the transmitter side, their coefficients can be optimised based on this information. In this paper several different transmitter diversity techniques are investigated, both employing a priori channel knowledge or not. Some practical implementation aspects are also briefly analysed.","PeriodicalId":336991,"journal":{"name":"2002 International Zurich Seminar on Broadband Communications Access - Transmission - Networking (Cat. No.02TH8599)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114601061","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}
引用次数: 4
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