Pub Date : 1991-12-02DOI: 10.1109/GLOCOM.1991.188476
R.A. Sukkar, J. LoCicero
A method is presented to arithmetically process signals in the LPC (linear predictive coding) domain. The focus of this work is on an LPC conference calling application where the LPC signals are added. As part of the solution, an interactive method for simultaneous pole-zero parameterizations of an impulse response is developed. Experimental results show that with only a few iterations, the simultaneous iterative method significantly outperforms J.L. Shanks' (1967) and R.E. Kalman's (1958) methods based on a mean-squared decibel error figure-of-merit. Using informal listening tests, the quality of the LPC conference calling speech was very close to the quality of the sum of the LPC estimates.<>
{"title":"Arithmetic processing of speech signals in the LPC domain","authors":"R.A. Sukkar, J. LoCicero","doi":"10.1109/GLOCOM.1991.188476","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188476","url":null,"abstract":"A method is presented to arithmetically process signals in the LPC (linear predictive coding) domain. The focus of this work is on an LPC conference calling application where the LPC signals are added. As part of the solution, an interactive method for simultaneous pole-zero parameterizations of an impulse response is developed. Experimental results show that with only a few iterations, the simultaneous iterative method significantly outperforms J.L. Shanks' (1967) and R.E. Kalman's (1958) methods based on a mean-squared decibel error figure-of-merit. Using informal listening tests, the quality of the LPC conference calling speech was very close to the quality of the sum of the LPC estimates.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126103379","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 : 1991-12-02DOI: 10.1109/GLOCOM.1991.188403
J. E. Baker
A technique that combines benefits of fast, distributed heuristics and of centralized optimal algorithms is proposed. As a form of preplanning, whenever the topology of the network is deliberately changed, new optimal rerouting plans are calculated, using a centralized or a distributed approach, for each possible total cable failure. These plans are used to calculate distance labels that are stored in the digital cross-connect systems or other switching elements. When a failure occurs, the nodes (switches) at either end of the failed cable start the execution of a distributed max-flow algorithm and communicate with their neighbors by message passing. As nodes become involved in the execution of the distributed algorithm, they imitate their state using the precalculated distance labels. An appropriate set of distance labels can be defined on a transformed version of the network such that, if no topology changes have occurred in the network since the labels were calculated, the algorithm immediately converges to the optimal solution. If, on the other hand, links and/or nodes have been removed since the labels were calculated, the algorithm will still function properly and converge to a solution that has the maximal number of restored circuits (although the restoration paths are not necessarily of shortest possible length).<>
{"title":"A distributed link restoration algorithm with robust preplanning","authors":"J. E. Baker","doi":"10.1109/GLOCOM.1991.188403","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188403","url":null,"abstract":"A technique that combines benefits of fast, distributed heuristics and of centralized optimal algorithms is proposed. As a form of preplanning, whenever the topology of the network is deliberately changed, new optimal rerouting plans are calculated, using a centralized or a distributed approach, for each possible total cable failure. These plans are used to calculate distance labels that are stored in the digital cross-connect systems or other switching elements. When a failure occurs, the nodes (switches) at either end of the failed cable start the execution of a distributed max-flow algorithm and communicate with their neighbors by message passing. As nodes become involved in the execution of the distributed algorithm, they imitate their state using the precalculated distance labels. An appropriate set of distance labels can be defined on a transformed version of the network such that, if no topology changes have occurred in the network since the labels were calculated, the algorithm immediately converges to the optimal solution. If, on the other hand, links and/or nodes have been removed since the labels were calculated, the algorithm will still function properly and converge to a solution that has the maximal number of restored circuits (although the restoration paths are not necessarily of shortest possible length).<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121026022","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 : 1991-12-02DOI: 10.1109/GLOCOM.1991.188346
P. Goli, V. Kumar, A. Reibman
The authors investigate the ability of a fault-tolerant ATM (asynchronous transfer mode) switch to switch the traffic generated by a variable bit rate video compression system. They also study the robustness of the video compression system to recover from the packet loss that is sustained in the ATM switch. Several cases are studied, including: fault-free performance; performance in the presence of single faults, with a focus on the effect of the location of the fault; the effect of the fault tolerant routing scheme employed; and the effect of varying the burst size of the video traffic. Based on the results of the study, recommendations are made on the mode of operation of the ATM switch.<>
{"title":"A combined performance study of a fault-tolerant ATM switch and a video compression system","authors":"P. Goli, V. Kumar, A. Reibman","doi":"10.1109/GLOCOM.1991.188346","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188346","url":null,"abstract":"The authors investigate the ability of a fault-tolerant ATM (asynchronous transfer mode) switch to switch the traffic generated by a variable bit rate video compression system. They also study the robustness of the video compression system to recover from the packet loss that is sustained in the ATM switch. Several cases are studied, including: fault-free performance; performance in the presence of single faults, with a focus on the effect of the location of the fault; the effect of the fault tolerant routing scheme employed; and the effect of varying the burst size of the video traffic. Based on the results of the study, recommendations are made on the mode of operation of the ATM switch.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"118 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121379562","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 : 1991-12-02DOI: 10.1109/GLOCOM.1991.188732
S. Wolf, C. Dvorak, R. Kubichek, C. South, R.A. Schaphorst, S. Voran
Possible future work in relating objective and subjective telecommunications system performance measures is discussed. The topics included are shortfalls of current objective and subjective methods; critical issues regarding objective and subjective measures for the wide range of new telecommunications services and transmission technologies; methodologies that should be used to develop and validate new performance measures; and suggestions for new work that needs to be done by industry, government, and standards bodies to assure the timely development of accurate objective measurements.<>
{"title":"Future work relating objective and subjective telecommunications system performance","authors":"S. Wolf, C. Dvorak, R. Kubichek, C. South, R.A. Schaphorst, S. Voran","doi":"10.1109/GLOCOM.1991.188732","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188732","url":null,"abstract":"Possible future work in relating objective and subjective telecommunications system performance measures is discussed. The topics included are shortfalls of current objective and subjective methods; critical issues regarding objective and subjective measures for the wide range of new telecommunications services and transmission technologies; methodologies that should be used to develop and validate new performance measures; and suggestions for new work that needs to be done by industry, government, and standards bodies to assure the timely development of accurate objective measurements.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121474499","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 : 1991-12-02DOI: 10.1109/GLOCOM.1991.188665
D. Ramsden
In-service, nonintrusive measurement on speech signals is a new technique for measuring transmission performance which does not require facilities be taken out of service to be tested. The capabilities and some potential applications of this new measurement technology are discussed. In-service, nonintrusive measurement devices (INMDs) measure speech level, dynamic noise, and echo path loss and delay on in-service voice connections. A major application for the INMD is the identification of facilities in switched networks that require maintenance. Current applications of the INMD have shown that its measurements can be used to identify loops, hybrids, and loss pads that do not meet design requirements and are causing performance problems.<>
{"title":"In-service, nonintrusive measurement on speech signals","authors":"D. Ramsden","doi":"10.1109/GLOCOM.1991.188665","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188665","url":null,"abstract":"In-service, nonintrusive measurement on speech signals is a new technique for measuring transmission performance which does not require facilities be taken out of service to be tested. The capabilities and some potential applications of this new measurement technology are discussed. In-service, nonintrusive measurement devices (INMDs) measure speech level, dynamic noise, and echo path loss and delay on in-service voice connections. A major application for the INMD is the identification of facilities in switched networks that require maintenance. Current applications of the INMD have shown that its measurements can be used to identify loops, hybrids, and loss pads that do not meet design requirements and are causing performance problems.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"454 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116765514","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 : 1991-12-02DOI: 10.1109/GLOCOM.1991.188374
S. Schulze, S. Webber
Increasing the level of customer satisfaction with their products and services is a key goal for the research and development organization of AG Communication Systems (AGCS R&D). To accomplish this objective, AGCS R&D has established strategic goals for improving quality and productivity. Metrics used to track progress against these goals have been identified. These goals and associated metrics focus on measuring customer satisfaction from specific points of view aimed at key customer focus areas. To measure AGCS R&D's progress in improving customer satisfaction as a whole, a customer satisfaction index was developed. The authors provide a description of the strategic goals, their associated metrics, the customer satisfaction index, and the strategies developed to achieve these goals.<>
{"title":"Improving customer satisfaction through establishing strategic goals for quality and productivity improvement","authors":"S. Schulze, S. Webber","doi":"10.1109/GLOCOM.1991.188374","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188374","url":null,"abstract":"Increasing the level of customer satisfaction with their products and services is a key goal for the research and development organization of AG Communication Systems (AGCS R&D). To accomplish this objective, AGCS R&D has established strategic goals for improving quality and productivity. Metrics used to track progress against these goals have been identified. These goals and associated metrics focus on measuring customer satisfaction from specific points of view aimed at key customer focus areas. To measure AGCS R&D's progress in improving customer satisfaction as a whole, a customer satisfaction index was developed. The authors provide a description of the strategic goals, their associated metrics, the customer satisfaction index, and the strategies developed to achieve these goals.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"100 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125217045","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 : 1991-12-02DOI: 10.1109/GLOCOM.1991.188458
C. Sierens, D. Mestdagh, G. van der Plas, J. Vandewege, G. Depovere, P. Debie
Subcarrier multiple access (SCMA) is described. It is a flexible access technique for passive optical networks (PONs), both for fiber-to-the home and fiber-to-the curb architectures. The main advantages of SCMA are the independence of the channels, which yields flexibility with respect to modulation format and evolution scenario, and the absence of synchronization between the different subscribers. Some results of SCMA experiments are presented. The capability of broadband channels is discussed, taking into account the optical interference effect. A comparison is made with other access techniques.<>
{"title":"Subcarrier multiple access for passive optical networks and comparison to other multiple access techniques","authors":"C. Sierens, D. Mestdagh, G. van der Plas, J. Vandewege, G. Depovere, P. Debie","doi":"10.1109/GLOCOM.1991.188458","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188458","url":null,"abstract":"Subcarrier multiple access (SCMA) is described. It is a flexible access technique for passive optical networks (PONs), both for fiber-to-the home and fiber-to-the curb architectures. The main advantages of SCMA are the independence of the channels, which yields flexibility with respect to modulation format and evolution scenario, and the absence of synchronization between the different subscribers. Some results of SCMA experiments are presented. The capability of broadband channels is discussed, taking into account the optical interference effect. A comparison is made with other access techniques.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131370742","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 : 1991-12-02DOI: 10.1109/GLOCOM.1991.188612
E. Del Re, G. Benelli, G. Castellini, R. Fantacci, L. Pierucci, L. Pogliani
A digital receiver suitable for use in the future GSM pan-European cellular system is described. The receiver uses a maximum-likelihood sequence estimation (MLSE) implemented by means of the Viterbi algorithm to compensate for the heavy selective distortions caused by multipath propagation. The performance of the receiver is evaluated through a channel simulator suitable for mobile communications. The results obtained show the good behavior characteristics for the receiver in different modes of operation. Easy implementation of the device using VLSI technology is expected.<>
{"title":"Design of a digital MLSE receiver for mobile radio communications","authors":"E. Del Re, G. Benelli, G. Castellini, R. Fantacci, L. Pierucci, L. Pogliani","doi":"10.1109/GLOCOM.1991.188612","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188612","url":null,"abstract":"A digital receiver suitable for use in the future GSM pan-European cellular system is described. The receiver uses a maximum-likelihood sequence estimation (MLSE) implemented by means of the Viterbi algorithm to compensate for the heavy selective distortions caused by multipath propagation. The performance of the receiver is evaluated through a channel simulator suitable for mobile communications. The results obtained show the good behavior characteristics for the receiver in different modes of operation. Easy implementation of the device using VLSI technology is expected.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131568938","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 : 1991-12-02DOI: 10.1109/GLOCOM.1991.188446
J. Holtzman, Louay M. A. Jalloul
The authors present an analysis of the mitigation of the Rayleigh fading effect for wideband direct sequence pseudonoise signaling. The reduction of the Rayleigh fading effect is an advantage of code division multiple access (CDMA) over narrowband transmission systems and it eases the burden of CDMA power control. A general expression for the standard deviation of the received wideband signal power is derived. It is shown how the standard deviation decreases as the bandwidth spreading increases. The authors also analyzes the time correlation needed for other analyses (e.g., CDMA power control).<>
{"title":"Rayleigh fading effect reduction with wideband DS/CDMA signals","authors":"J. Holtzman, Louay M. A. Jalloul","doi":"10.1109/GLOCOM.1991.188446","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188446","url":null,"abstract":"The authors present an analysis of the mitigation of the Rayleigh fading effect for wideband direct sequence pseudonoise signaling. The reduction of the Rayleigh fading effect is an advantage of code division multiple access (CDMA) over narrowband transmission systems and it eases the burden of CDMA power control. A general expression for the standard deviation of the received wideband signal power is derived. It is shown how the standard deviation decreases as the bandwidth spreading increases. The authors also analyzes the time correlation needed for other analyses (e.g., CDMA power control).<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"284 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131607653","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 : 1991-12-02DOI: 10.1109/GLOCOM.1991.188699
H. Hashemi
A simulation package for predicting the impulse response of the digital mobile radio propagation channel has been modified to take into account reflection and scattering of the transmitted signals by distant objects such as hills, mountains, and city skylines. For each distant reflector the round trip path loss is calculated using a model derived from the available information in the literature. Impulse response profiles with excess delays of up to 200 mu s were then generated by repeatedly calling the original simulation package, scaling the resulting subprofiles properly, and combining them by vector addition of all the multipath components. The final model indicates that retarded echoes with magnitudes comparable to the line-of-sight path are possible under favorable propagation conditions from base to mobile through the reflected path, and unfavorable propagation conditions through the direct path.<>
{"title":"Simulation of the urban radio propagation channel in the presence of distant reflectors","authors":"H. Hashemi","doi":"10.1109/GLOCOM.1991.188699","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188699","url":null,"abstract":"A simulation package for predicting the impulse response of the digital mobile radio propagation channel has been modified to take into account reflection and scattering of the transmitted signals by distant objects such as hills, mountains, and city skylines. For each distant reflector the round trip path loss is calculated using a model derived from the available information in the literature. Impulse response profiles with excess delays of up to 200 mu s were then generated by repeatedly calling the original simulation package, scaling the resulting subprofiles properly, and combining them by vector addition of all the multipath components. The final model indicates that retarded echoes with magnitudes comparable to the line-of-sight path are possible under favorable propagation conditions from base to mobile through the reflected path, and unfavorable propagation conditions through the direct path.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"228 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121863034","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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