Pub Date : 1991-12-02DOI: 10.1109/GLOCOM.1991.188413
K. Ahmed, M. Hluchyj
The authors compare recently developed timing recovery methods for circuit emulation in broadband packet networks. It is generally believed that synchronous methods such as the synchronous frequency encoding technique (SFET) offer faster convergence and simpler implementation than phase-lock techniques that recover source rate from the jittery packet arrival stream. It is shown that this belief does not extend to recently reported phase-lock methods, particularly the time difference of arrival (TDOA) estimator. The authors derive the convergence behavior of the TDOA method and show that it is comparable to SFET. It is also shown that the implementation complexities of the two methods are comparable.<>
{"title":"ATM circuit emulation-a comparison of recent techniques","authors":"K. Ahmed, M. Hluchyj","doi":"10.1109/GLOCOM.1991.188413","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188413","url":null,"abstract":"The authors compare recently developed timing recovery methods for circuit emulation in broadband packet networks. It is generally believed that synchronous methods such as the synchronous frequency encoding technique (SFET) offer faster convergence and simpler implementation than phase-lock techniques that recover source rate from the jittery packet arrival stream. It is shown that this belief does not extend to recently reported phase-lock methods, particularly the time difference of arrival (TDOA) estimator. The authors derive the convergence behavior of the TDOA method and show that it is comparable to SFET. It is also shown that the implementation complexities of the two methods are comparable.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"1 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":"115391401","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.1991.188636
I. Seto, T. Ohtsuki, Hiroyuki Yshima, I. Sasase, S. Mori
A polarization-shift-keying (POLSK) homodyne system using phase-diversity receivers is proposed. It has the advantages of both the homodyning and the polarization modulation scheme. Hence, it is attractive at a high bit rate and has no power penalty and no floor due to the influence of phase noise and offset frequency in the bit-error-rate (BER) performance. The authors theoretically analyze the receiver sensitivity and find that it is equal to that of the POLSK heterodyne system and that at a high signal-to-noise ratio (SNR), the degradation of the receiver sensitivity in the proposed system is much smaller than that in DPSK phase-diversity homodyne systems.<>
{"title":"Coherent optical polarization-shift-keying (POLSK) homodyne system using phase-diversity receivers","authors":"I. Seto, T. Ohtsuki, Hiroyuki Yshima, I. Sasase, S. Mori","doi":"10.1109/GLOCOM.1991.188636","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188636","url":null,"abstract":"A polarization-shift-keying (POLSK) homodyne system using phase-diversity receivers is proposed. It has the advantages of both the homodyning and the polarization modulation scheme. Hence, it is attractive at a high bit rate and has no power penalty and no floor due to the influence of phase noise and offset frequency in the bit-error-rate (BER) performance. The authors theoretically analyze the receiver sensitivity and find that it is equal to that of the POLSK heterodyne system and that at a high signal-to-noise ratio (SNR), the degradation of the receiver sensitivity in the proposed system is much smaller than that in DPSK phase-diversity homodyne systems.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"21 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":"115618339","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.1991.188409
H. Badran, H. Mouftah
The performance of nonblocking input-output-buffered ATM (asynchronous transfer mode) switch architectures with backpressure control is investigated, when operating under different selection mechanisms. The unfairness problem associated with the classical cyclic service mechanism in broadband switches with input and output buffering and backpressure control is explained and three alternative service or selection mechanisms are proposed. The proposed selection policies are compared from the point of view of fairness, implementation complexity, and cell loss performance. The different selection policies have a strong impact on the (complementary) input queue length distributions and the cell loss behavior of the switch. It is found that the queue length criterion results in a significantly better performance in terms of queue length distribution and cell loss behavior, and is easier to implement than other selection criteria that involve time stamping.<>
{"title":"Head of line arbitration in ATM switches with input-output buffering and backpressure control","authors":"H. Badran, H. Mouftah","doi":"10.1109/GLOCOM.1991.188409","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188409","url":null,"abstract":"The performance of nonblocking input-output-buffered ATM (asynchronous transfer mode) switch architectures with backpressure control is investigated, when operating under different selection mechanisms. The unfairness problem associated with the classical cyclic service mechanism in broadband switches with input and output buffering and backpressure control is explained and three alternative service or selection mechanisms are proposed. The proposed selection policies are compared from the point of view of fairness, implementation complexity, and cell loss performance. The different selection policies have a strong impact on the (complementary) input queue length distributions and the cell loss behavior of the switch. It is found that the queue length criterion results in a significantly better performance in terms of queue length distribution and cell loss behavior, and is easier to implement than other selection criteria that involve time stamping.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"86 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":"115684326","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.1991.188523
D. Stevenson
Some of the issues that arise when carrying gigabit-per-second supercomputer traffic on ATM networks are discussed. In particular, asynchronous transfer mode (ATM) and upper layer protocols, and other application issues are addressed. Experiences in the application of broadband networks for supercomputer communications are related to these issues.<>
{"title":"Supercomputer communications as an application for broadband networks","authors":"D. Stevenson","doi":"10.1109/GLOCOM.1991.188523","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188523","url":null,"abstract":"Some of the issues that arise when carrying gigabit-per-second supercomputer traffic on ATM networks are discussed. In particular, asynchronous transfer mode (ATM) and upper layer protocols, and other application issues are addressed. Experiences in the application of broadband networks for supercomputer communications are related to these issues.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"134 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":"115902055","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.1991.188482
R. Ledonne, P. Passeri
A description is presented of the characteristics of the Italian telecommunications network, considering the impact of the SDH (synchronous digital hierarchy) transmission equipment with respect to the present plesiochronous network. Applications both in intercity, urban junction, and the distribution network are described. In addition, characteristics of SDH equipment to be introduced in the network in the short term are described.<>
{"title":"Introduction of the SDH systems into the Italian network","authors":"R. Ledonne, P. Passeri","doi":"10.1109/GLOCOM.1991.188482","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188482","url":null,"abstract":"A description is presented of the characteristics of the Italian telecommunications network, considering the impact of the SDH (synchronous digital hierarchy) transmission equipment with respect to the present plesiochronous network. Applications both in intercity, urban junction, and the distribution network are described. In addition, characteristics of SDH equipment to be introduced in the network in the short term are described.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"24 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":"114506689","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.1991.188473
S. Ono
A 8 kb/s speech coder in which the one-way coding delay is less than 3.75 ms is described. The proposed coder is a LDCELP (low delay code excited linear predictive coders) incorporating a FSVQ (finite state vector quantizer). A FSVQ is a switched vector quantizer with a backward selecting mechanism, and it is able to improve coding performance without increasing delay. Experimental results confirm that the incorporation of a 4-state FSVQ with a 1-frame state transition memory into a LDCELP provides 0.6 dB improvement in signal-to-noise ratio, and that the incorporation of a 4-state FSVQ with 3-frame state transition memories into a LDCELP provides 1.0 dB improvement. The signal-to-noise ratios of these two proposed LDCELPs are 13.7 dB and 14.1 dB, respectively.<>
{"title":"8 kb/s low delay CELP with feedback vector quantization","authors":"S. Ono","doi":"10.1109/GLOCOM.1991.188473","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188473","url":null,"abstract":"A 8 kb/s speech coder in which the one-way coding delay is less than 3.75 ms is described. The proposed coder is a LDCELP (low delay code excited linear predictive coders) incorporating a FSVQ (finite state vector quantizer). A FSVQ is a switched vector quantizer with a backward selecting mechanism, and it is able to improve coding performance without increasing delay. Experimental results confirm that the incorporation of a 4-state FSVQ with a 1-frame state transition memory into a LDCELP provides 0.6 dB improvement in signal-to-noise ratio, and that the incorporation of a 4-state FSVQ with 3-frame state transition memories into a LDCELP provides 1.0 dB improvement. The signal-to-noise ratios of these two proposed LDCELPs are 13.7 dB and 14.1 dB, respectively.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"35 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":"114667423","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.1991.188466
K. Khalil, P. Spencer
A systematic approach that allows network planners to design networks in a cost-effective way and that provides guidelines for tuning existing LANs (local area networks) to achieve better performance is introduced. It also allows network administrators to decide when and how to upgrade networks. Unlike the current ad hoc approaches, the proposed approach is based on the projection of the user traffic demands or on the real traffic measured from operational networks. The essence of this approach is to group users that communicate heavily among each other on the same network segment, and then to interconnect various segments to provide full connectivity. This approach has become possible by the availability of twisted-pair and fiber optic LANs supporting hub wiring. Hubbed architectures significantly reduce the design limitations imposed by the physical locations of users, and, in most cases, simplify the movement of users from one segment to another regardless their physical locations. Several design algorithms have been developed to improve the performance of the networks. These algorithms maximize the locality of traffic within each segment and balance the load across various segments. Various network architectures are also discussed.<>
{"title":"A systematic approach for planning, tuning and upgrading local area networks","authors":"K. Khalil, P. Spencer","doi":"10.1109/GLOCOM.1991.188466","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188466","url":null,"abstract":"A systematic approach that allows network planners to design networks in a cost-effective way and that provides guidelines for tuning existing LANs (local area networks) to achieve better performance is introduced. It also allows network administrators to decide when and how to upgrade networks. Unlike the current ad hoc approaches, the proposed approach is based on the projection of the user traffic demands or on the real traffic measured from operational networks. The essence of this approach is to group users that communicate heavily among each other on the same network segment, and then to interconnect various segments to provide full connectivity. This approach has become possible by the availability of twisted-pair and fiber optic LANs supporting hub wiring. Hubbed architectures significantly reduce the design limitations imposed by the physical locations of users, and, in most cases, simplify the movement of users from one segment to another regardless their physical locations. Several design algorithms have been developed to improve the performance of the networks. These algorithms maximize the locality of traffic within each segment and balance the load across various segments. Various network architectures are also discussed.<<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":"121979346","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.1991.188731
F. Calliss
A new form of code analysis is presented aimed at helping a programmer assess the quality of a program's code. A description of object-oriented designed systems is given. Different classifications of modules used to assess the quality of the code of an object-oriented system are given, and techniques to analyze a system's source code are described. These classifications are discussed in the context of telecommunication software. Analysis techniques are presented to detect these modules. In addition, some techniques for assessing the quality of a module or of the connection between two modules are presented.<>
{"title":"Assessing the quality of object-oriented designed systems","authors":"F. Calliss","doi":"10.1109/GLOCOM.1991.188731","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188731","url":null,"abstract":"A new form of code analysis is presented aimed at helping a programmer assess the quality of a program's code. A description of object-oriented designed systems is given. Different classifications of modules used to assess the quality of the code of an object-oriented system are given, and techniques to analyze a system's source code are described. These classifications are discussed in the context of telecommunication software. Analysis techniques are presented to detect these modules. In addition, some techniques for assessing the quality of a module or of the connection between two modules are presented.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"3 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":"116870574","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.1991.188625
A. Ganz, Yao Gao
The authors present efficient scheduling algorithms for the slot assignment problem in a satellite-switched time-division multiple-access (SS/TDMA) system. This problem is translated into a modified openshop scheduling problem, allowing the use of known optimal algorithms. Their complexity is expressed as a function of the following parameters: the number of nonzero entries in the demand matrix, the number of uplinks, and the number of downlinks. According to the values of these parameters, the algorithm with the lowest computational complexity can be adopted. While the computational complexity of previously published algorithms is greatly reduced, simulation results evidence that the assignment duration is close to previously presented solutions.<>
{"title":"Efficient algorithms for SS/TDMA scheduling","authors":"A. Ganz, Yao Gao","doi":"10.1109/GLOCOM.1991.188625","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188625","url":null,"abstract":"The authors present efficient scheduling algorithms for the slot assignment problem in a satellite-switched time-division multiple-access (SS/TDMA) system. This problem is translated into a modified openshop scheduling problem, allowing the use of known optimal algorithms. Their complexity is expressed as a function of the following parameters: the number of nonzero entries in the demand matrix, the number of uplinks, and the number of downlinks. According to the values of these parameters, the algorithm with the lowest computational complexity can be adopted. While the computational complexity of previously published algorithms is greatly reduced, simulation results evidence that the assignment duration is close to previously presented solutions.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"25 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":"125727016","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.1991.188559
C. Carlisle, Desmond P. Taylor, M. Shafi, W. K. Kennedy
Upper bounds have been formulated and computed for the error probability of TCM (trellis-coded modulation) on time-dispersive channels. Accurate approximations to ISI (intersymbol interference) PDF's have been used in the formulation. Examples have shown the bounds to be sufficiently tight over a wide range of time-dispersive channel conditions for practical applications. For severe levels of ISI, the bounds must be optimized over a bounding parameter to yield tight bounds; however, for low levels of ISI, a fixed bounding parameter can be used to yield tight bounds. A further simplification that can be used for low levels of ISI is to assume that the ISI has a Gaussian PDF, to avoid having to compute an approximate PDF.<>
{"title":"Performance bounds for trellis-coded modulation on time-dispersive channels","authors":"C. Carlisle, Desmond P. Taylor, M. Shafi, W. K. Kennedy","doi":"10.1109/GLOCOM.1991.188559","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188559","url":null,"abstract":"Upper bounds have been formulated and computed for the error probability of TCM (trellis-coded modulation) on time-dispersive channels. Accurate approximations to ISI (intersymbol interference) PDF's have been used in the formulation. Examples have shown the bounds to be sufficiently tight over a wide range of time-dispersive channel conditions for practical applications. For severe levels of ISI, the bounds must be optimized over a bounding parameter to yield tight bounds; however, for low levels of ISI, a fixed bounding parameter can be used to yield tight bounds. A further simplification that can be used for low levels of ISI is to assume that the ISI has a Gaussian PDF, to avoid having to compute an approximate PDF.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"104 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":"124807849","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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