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Performance analysis of conventional RAKE receivers with channel estimation for a BPSK WCDMA downlink 基于BPSK WCDMA下行信道估计的传统RAKE接收机性能分析
教育传播与技术 Pub Date : 2000-10-19 DOI: 10.1109/SCVT.2000.923362
M. Guenach, L. Vandendorpe
{"title":"Performance analysis of conventional RAKE receivers with channel estimation for a BPSK WCDMA downlink","authors":"M. Guenach, L. Vandendorpe","doi":"10.1109/SCVT.2000.923362","DOIUrl":"https://doi.org/10.1109/SCVT.2000.923362","url":null,"abstract":"In this paper, we investigate the performance of conventional RAKE receivers using maximum ratio combining (MRC) for a UMTS terrestrial radio wideband code division multiple access (UTRA-WCDMA) downlink. Both perfect and non-perfect multipath slowly Rayleigh fading channel estimations are considered. Exact bit error probabilities (BER) are derived, using quadratic forms and characteristic functions, for BPSK modulation. The users may have different bit rates. Then, the mean-squared estimation error (MSEE) of the channel tap weights is computed and compared to the Cramer-Rao lower bound (CRLB).","PeriodicalId":58934,"journal":{"name":"教育传播与技术","volume":"54 1","pages":"194-201"},"PeriodicalIF":0.0,"publicationDate":"2000-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74618744","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
WHT/OFDM - an improved OFDM transmission method for selective fading channels WHT/OFDM -一种改进的选择性衰落信道OFDM传输方法
教育传播与技术 Pub Date : 2000-10-19 DOI: 10.1109/SCVT.2000.923353
Z. Dlugaszewski, K. Wesołowski
{"title":"WHT/OFDM - an improved OFDM transmission method for selective fading channels","authors":"Z. Dlugaszewski, K. Wesołowski","doi":"10.1109/SCVT.2000.923353","DOIUrl":"https://doi.org/10.1109/SCVT.2000.923353","url":null,"abstract":"The application of the Walsh-Hadamard transformation is proposed as the means to combat the influence of selective fading on the OFDM system performance. Substantial improvement as compared with the OFDM system applying the adaptive equalizer at the receiver is shown by simulation.","PeriodicalId":58934,"journal":{"name":"教育传播与技术","volume":"85 1","pages":"144-149"},"PeriodicalIF":0.0,"publicationDate":"2000-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79394686","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: 59
Understanding TCP's behavior over wireless links 了解TCP在无线链路上的行为
教育传播与技术 Pub Date : 2000-10-19 DOI: 10.1109/SCVT.2000.923350
F. Lefevre, Guillaume Vivier, Motorola
{"title":"Understanding TCP's behavior over wireless links","authors":"F. Lefevre, Guillaume Vivier, Motorola","doi":"10.1109/SCVT.2000.923350","DOIUrl":"https://doi.org/10.1109/SCVT.2000.923350","url":null,"abstract":"During the last few years, both Internet and mobile systems have grown extremely fast. It is natural that nowadays these two worlds are converging. Adaptation of protocols designed for the wired Internet, such as TCP, to wireless specificity and conversely, design of wireless systems adapted to the Internet protocol stack is an area of wide interest. Many materials can be found in the research community but are often unreachable for the ordinary reader. This paper tries to explain basic TCP functionality and its behaviour over mobile cellular systems. Simulations highlight the spurious effects of the congestion avoidance algorithm of TCP, unwisely triggered by the bad quality of the wireless link. Then a survey and an analysis of the main propositions to improve TCP behaviour over wireless is given, to finally conclude that unfortunately there is no miraculous solution.","PeriodicalId":58934,"journal":{"name":"教育传播与技术","volume":"110 1","pages":"123-130"},"PeriodicalIF":0.0,"publicationDate":"2000-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76766674","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: 58
Problems related to the QoS-sensitive delivery of Internet services to mobile users over GPRS 与通过GPRS向移动用户提供对质量敏感的互联网服务有关的问题
教育传播与技术 Pub Date : 2000-10-19 DOI: 10.1109/SCVT.2000.923342
K. Koutsopoulos, C. Konstantinopoulou, S. Kotrotsos, N. Alexiou, P. Demestichas, M. Theologou
{"title":"Problems related to the QoS-sensitive delivery of Internet services to mobile users over GPRS","authors":"K. Koutsopoulos, C. Konstantinopoulou, S. Kotrotsos, N. Alexiou, P. Demestichas, M. Theologou","doi":"10.1109/SCVT.2000.923342","DOIUrl":"https://doi.org/10.1109/SCVT.2000.923342","url":null,"abstract":"The current research in the field of telecommunications focuses on the provision of Internet services to mobile users over GPRS (General Packet Radio Service), under a set of QoS requirements. This paper discusses problems that have to be resolved in order to support an adequate QoS level in: (a) the communication between the TE (terminal equipment) and the MT (mobile terminal) of the MS (mobile station), (b) the GPRS segment and (c) the Internet segment. As far as the communication between the TE and the MT is concerned, a software entity that controls the information transfer in the protocol stack and is QoS aware is considered. For the solution of the QoS study in the GPRS segment, a simulation platform is considered. Finally, the problem of the configuration of the Internet segment is mainly targeted to the definition of the appropriate service classes in the Internet segment that will satisfy the QoS requirements of the services that originate from the GPRS segment.","PeriodicalId":58934,"journal":{"name":"教育传播与技术","volume":"87 1","pages":"75-81"},"PeriodicalIF":0.0,"publicationDate":"2000-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79554879","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
Estimation of spectral efficiency for MC/DS-CDMA in cellular systems 蜂窝系统中MC/DS-CDMA频谱效率的估计
教育传播与技术 Pub Date : 2000-10-19 DOI: 10.1109/SCVT.2000.923340
P. Varzakas, G. Tombras
{"title":"Estimation of spectral efficiency for MC/DS-CDMA in cellular systems","authors":"P. Varzakas, G. Tombras","doi":"10.1109/SCVT.2000.923340","DOIUrl":"https://doi.org/10.1109/SCVT.2000.923340","url":null,"abstract":"Spectral efficiency is of primary concern in the design of future wireless communications systems. The spectral efficiency achieved by a multicarrier direct-sequence code-division multiple access (MC/DS-CDMA) cellular system operating in a mobile radio environment with Rayleigh fading, is investigated. Spectral efficiency is evaluated in terms of channel capacity (in the Shannon sense) available to each user, estimated in an average sense. It is analytically shown that, under normalized conditions, MC/DS-CDMA spectral efficiency, on downlink, is higher than that of single-carrier DS-CDMA (SC/DS-CDMA). This result is justified by the combination of path-diversity reception, achieved by a conventional coherent RAKE receiver, and frequency diversity provided, in a fading environment, by frequency division multiplexing on a set of orthogonal carriers.","PeriodicalId":58934,"journal":{"name":"教育传播与技术","volume":"111 3S 1","pages":"62-68"},"PeriodicalIF":0.0,"publicationDate":"2000-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89157865","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
End-to-end quality of service issues over next generation mobile Internet 下一代移动互联网的端到端服务质量问题
教育传播与技术 Pub Date : 2000-10-19 DOI: 10.1109/SCVT.2000.923355
S. Maniatis, C. Grecas, I. Venieris
{"title":"End-to-end quality of service issues over next generation mobile Internet","authors":"S. Maniatis, C. Grecas, I. Venieris","doi":"10.1109/SCVT.2000.923355","DOIUrl":"https://doi.org/10.1109/SCVT.2000.923355","url":null,"abstract":"The Internet protocol (IP) dominates in today's data communication infrastructures. The network evolution also favours the explosion of wireless network technologies. The immediate response is to make wireless networks deliver IP services at a guaranteed end-to-end level of quality. Under this scope, this paper discusses the support of quality-assured services over next-generation mobile Internet, provided by UMTS. On the core network, interworking with DiffServ- and IntServ-capable domains is assumed. The paper proposes fundamental architectural modules that must be supported to provide for data delivery performance.","PeriodicalId":58934,"journal":{"name":"教育传播与技术","volume":"110 1","pages":"150-154"},"PeriodicalIF":0.0,"publicationDate":"2000-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74651439","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: 15
CA-CDMA: channel adapted CDMA for MAI/ISI free burst transmission CA-CDMA:用于MAI/ISI自由突发传输的信道适应CDMA
教育传播与技术 Pub Date : 2000-10-19 DOI: 10.1109/SCVT.2000.923361
F. Horlin, L. Vandendorpe
{"title":"CA-CDMA: channel adapted CDMA for MAI/ISI free burst transmission","authors":"F. Horlin, L. Vandendorpe","doi":"10.1109/SCVT.2000.923361","DOIUrl":"https://doi.org/10.1109/SCVT.2000.923361","url":null,"abstract":"In this paper, a new precoding scheme is designed allowing the complete orthogonalization of the users in the uplink of a multiuser CDMA system based on burst transmission. With this channel adapted precoding, all the inter-symbol and inter-user interferences are eliminated thanks to the appropriate linear processing at the receiver. If the received power is fixed, this system minimizes the variance of the symbol estimation error. An infinity of solutions exists to orthogonalize the system. Two objectives are added: a possible recursion in the number of users and a minimization of the average emitted power. The last optimization problem is a complex one. An approximate solution is proposed. It is shown that the system introduced in this paper outperforms burst system using a conventional set of codes.","PeriodicalId":58934,"journal":{"name":"教育传播与技术","volume":"91 1","pages":"186-193"},"PeriodicalIF":0.0,"publicationDate":"2000-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90626397","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
Data transfer schemes for 3G mobile telecommunication systems 3G移动通信系统的数据传输方案
教育传播与技术 Pub Date : 2000-10-19 DOI: 10.1109/SCVT.2000.923337
J. Markoulidakis, G. Lyberopoulos, D. F. Tsirkas, C.N. Konstantinopoulou, K. Koutsopoulos
{"title":"Data transfer schemes for 3G mobile telecommunication systems","authors":"J. Markoulidakis, G. Lyberopoulos, D. F. Tsirkas, C.N. Konstantinopoulou, K. Koutsopoulos","doi":"10.1109/SCVT.2000.923337","DOIUrl":"https://doi.org/10.1109/SCVT.2000.923337","url":null,"abstract":"In mobile communications, distributed database systems fulfill the requirements of storing, accessing and updating user-related data (service profile, location and charging data, security related parameters, etc.). Second generation systems adopt the home location register (HLR)/visitor location register (VLR) concept, while for third generation (3G) systems, a number of advanced schemes has been proposed. A common issue inherent in all schemes is the transfer of user data from one database node to another whenever the user changes node area. In this paper, we propose a general data transfer scheme, which allows the grouping of database nodes into \"domains\". The advantage of this scheme is that user data is transferred to a new node, only in case that the user changes domain. The applicability of the proposed scheme for both second and third generation systems is investigated from the functional and performance viewpoints. The performance analysis is based on a simulation model and focuses on the transaction load, the signaling load and the procedure execution delay. The results indicate that the database performance improves as the domain size increases. The limiting factor is the resulting procedure execution delay, due to the increased distance between the actual user location and the node where the user data is stored. Possible enhancements which aim at further performance improvements (e.g., taking into account the user mobility characteristics) are also discussed.","PeriodicalId":58934,"journal":{"name":"教育传播与技术","volume":"45 1","pages":"34-41"},"PeriodicalIF":0.0,"publicationDate":"2000-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86514463","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
Wavelet packet based multicarrier modulation 基于小波包的多载波调制
教育传播与技术 Pub Date : 2000-10-19 DOI: 10.1109/SCVT.2000.923351
C. Van Bouwel, J. Potemans, S. Schepers, B. Nauwelaers, A. R. Van de Capelle
{"title":"Wavelet packet based multicarrier modulation","authors":"C. Van Bouwel, J. Potemans, S. Schepers, B. Nauwelaers, A. R. Van de Capelle","doi":"10.1109/SCVT.2000.923351","DOIUrl":"https://doi.org/10.1109/SCVT.2000.923351","url":null,"abstract":"A recent but already popular technique for broadband communications is multicarrier modulation, which divides the channel into several orthogonal, overlapping subchannels. Multicarrier modulation is normally implemented using a Fourier transform to create and detect the different subcarriers. This can be efficiently implemented using an (I)FFT. This transform however has the drawback that it uses a rectangular window, which creates rather high sidelobes. This leads to rather high interference when the channel impairments cannot be fully compensated. Looking at other transforms leads us to the wavelet transform, and more specifically the wavelet packet transform, which has more flexibility and due to the time-overlap can have much lower sidelobes. This article studies the implementation of these wavelet packets, and the effects this implementation has on the requirements imposed in the design of usable wavelets. It is shown that the restrictions imposed by the perfect reconstruction requirement necessitate the use of biorthogonal wavelets. This however influences the performance. Moreover, the frequency behaviour of the wavelet packet transform is not straightforward which limits the practical use of this transform in a multicarrier system.","PeriodicalId":58934,"journal":{"name":"教育传播与技术","volume":"16 1","pages":"131-138"},"PeriodicalIF":0.0,"publicationDate":"2000-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78790008","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: 52
A comparison of HIPERLAN/2 and IEEE 802.11a physical and MAC layers HIPERLAN/2和IEEE 802.11a物理层和MAC层的比较
教育传播与技术 Pub Date : 2000-10-19 DOI: 10.1109/SCVT.2000.923334
A. Doufexi, S. Armour, A. Nix, D. Bull
{"title":"A comparison of HIPERLAN/2 and IEEE 802.11a physical and MAC layers","authors":"A. Doufexi, S. Armour, A. Nix, D. Bull","doi":"10.1109/SCVT.2000.923334","DOIUrl":"https://doi.org/10.1109/SCVT.2000.923334","url":null,"abstract":"At present, wireless local area networks (WLANs) supporting broadband multimedia communication are being developed and standardized. Two such standards are HIPERLAN/2, defined by ETSI BRAN and the IEEE's 802.11a. These WLAN standards will provide data rates up to 54 Mbps (in a channel spacing of 20 MHz) in the 5.2 GHz band. In this paper, an overview of the the standards is presented together with software simulated physical layer performance results for each of the transmission modes defined in the two standards. Furthermore, the differences between the standards (protocol data unit-PDU-size, upper protocol layers etc.) and the effects on applications are discussed.","PeriodicalId":58934,"journal":{"name":"教育传播与技术","volume":"40 1","pages":"14-20"},"PeriodicalIF":0.0,"publicationDate":"2000-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83643284","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: 48
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