教育传播与技术 Pub Date : 2000-10-19 DOI: 10.1109/SCVT.2000.923338

S. Imre, L. Pap

引用次数: 2

Achievable accuracy of site-specific channel modelling for indoor wireless systems simulations 室内无线系统模拟中特定地点信道建模的可实现精度

教育传播与技术 Pub Date : 2000-10-19 DOI: 10.1109/SCVT.2000.923332

S. Loredo, L. Valle, R. Torres

引用次数: 0

Core network planning, optimization and forecasting in GSM/GPRS networks GSM/GPRS网的核心网规划、优化和预测

教育传播与技术 Pub Date : 2000-10-19 DOI: 10.1109/SCVT.2000.923339

C. Konstantinopoulou, K. Koutsopoulos, G. Lyberopoulos, M. Theologou

引用次数: 16

Efficient direct-sequence code acquisition in spread-spectrum communication systems 扩频通信系统中有效的直接序列码采集

教育传播与技术 Pub Date : 2000-10-19 DOI: 10.1109/SCVT.2000.923335

G. Giunta, A. Neri, M. Carli

{"title":"Efficient direct-sequence code acquisition in spread-spectrum communication systems","authors":"G. Giunta, A. Neri, M. Carli","doi":"10.1109/SCVT.2000.923335","DOIUrl":"https://doi.org/10.1109/SCVT.2000.923335","url":null,"abstract":"In order to exploit the advantages of a direct-sequence (DS) spread-spectrum (SS) signal in a code-division multiple access (CDMA) system, receivers must first be able to synchronize the local pseudo-noise (PN) code with the received PN code. Code acquisition is often carried out by a serial search procedure, particularly suited for the downlink of third generation mobile communication systems. The simplest of such techniques is the fixed dwell-time method. In this contribution, we deal with the more general multiple-dwell method. An interesting conclusion is that multiple dwells can result in a significant reduction of the mean acquisition time, while all the possible acquisition times are conversely bounded by a limited maximum waiting time. In order to perform an optimum search procedure, both non-detection and false-alarm probabilities of the multi-dwell test may be evaluated by means of the novel class of generalized Q (GQ) functions, characterized by a lower computational cost than numerical integration, that extend the well-known Marcum's Q-function. A number of operating examples of double-dwell serial search have been investigated. In all the considered examples, the devised testing procedure has significantly enhanced the performance of the acquisition system, reducing the mean acquisition time of the whole search.","PeriodicalId":58934,"journal":{"name":"教育传播与技术","volume":"57 2 1","pages":"21-27"},"PeriodicalIF":0.0,"publicationDate":"2000-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82765812","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

Initial investigation of multiple-input multiple-output (MIMO) channels in indoor environments 室内多输入多输出(MIMO)信道的初步研究

教育传播与技术 Pub Date : 2000-10-19 DOI: 10.1109/SCVT.2000.923352

D. McNamara, M. Beach, P. Fletcher, P. Karlsson

引用次数: 35

A generalization of a coherence multiplexing system 相干复用系统的一种推广

教育传播与技术 Pub Date : 2000-10-19 DOI: 10.1109/SCVT.2000.923333

A. Meijerink, G. Heideman, N.C. Van Etten

{"title":"A generalization of a coherence multiplexing system","authors":"A. Meijerink, G. Heideman, N.C. Van Etten","doi":"10.1109/SCVT.2000.923333","DOIUrl":"https://doi.org/10.1109/SCVT.2000.923333","url":null,"abstract":"Coherence multiplexing is a relatively unknown form of a CDMA-system, especially used in access networks for optical communication systems. Usually a coherence multiplex system uses delay-filters at the transmitter and at the receiver to perform the code. In this paper, an extension to other filter types is described. The performance, in terms of the signal-to-noise ratio, can be calculated. The result is a simple expression in which only the bit-time, the coherence-time of the source and the number of simultaneous users is involved. With the use of a continuous source, the signal to noise ratio will be proportional to the inverse of the square of the number of simultaneous users. Such a system is in fact a spectral code system. Further extension will be made with the use of a pulsed source and by replacing the filters in the previous case by a bank of filters. Each element of that filter bank also has a delay, different for each element, included. It will be shown that in that case the signal-to-noise ratio can be made proportional to the inverse of the number of users instead of the square of the number of users, which means an important improvement with respect to the number of users that can be handled. This system can be named a spectro-temporal code system.","PeriodicalId":58934,"journal":{"name":"教育传播与技术","volume":"6 1","pages":"6-13"},"PeriodicalIF":0.0,"publicationDate":"2000-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73243051","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

Problem areas related to the development and validation of management strategies for UMTS 与UMTS管理策略的制定和验证相关的问题领域

教育传播与技术 Pub Date : 2000-10-19 DOI: 10.1109/SCVT.2000.923349

Panagiotis Demestichas, A. Taskaris, C. Gizelis, A. Igoumenidis, E. Tzifa, M. Theologou, N. Mitrou