Pub Date : 1991-12-02DOI: 10.1109/GLOCOM.1991.188435
A. Ganz, B. Li
The authors present a performance study of a satellite cluster consisting of m satellites interconnected through intersatellite links (ISLs). In each satellite, the uplinks are operated under the slotted ALOHA policy, while the downlinks and intersatellite links are operated employing the TDM (time division multiplexing) policy. The packets successfully arriving at the satellite from the earth zones and from the ISLs are stored onboard the satellite. The satellite cluster performance is expressed in terms of throughput. The performance measure is obtained as a function of the system load and traffic distribution, and of the system configuration in terms of the number of uplinks, number of downlinks, number of buffers, number of transponders, and the ISL capacity. As an exact Markov modeling of the above system leads to intractable solutions, a tractable approximate analysis is introduced. The introduced analysis can be used to investigate the sensitivity of the system performance as a function of the system configuration.<>
{"title":"Design and analysis of satellite clusters","authors":"A. Ganz, B. Li","doi":"10.1109/GLOCOM.1991.188435","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188435","url":null,"abstract":"The authors present a performance study of a satellite cluster consisting of m satellites interconnected through intersatellite links (ISLs). In each satellite, the uplinks are operated under the slotted ALOHA policy, while the downlinks and intersatellite links are operated employing the TDM (time division multiplexing) policy. The packets successfully arriving at the satellite from the earth zones and from the ISLs are stored onboard the satellite. The satellite cluster performance is expressed in terms of throughput. The performance measure is obtained as a function of the system load and traffic distribution, and of the system configuration in terms of the number of uplinks, number of downlinks, number of buffers, number of transponders, and the ISL capacity. As an exact Markov modeling of the above system leads to intractable solutions, a tractable approximate analysis is introduced. The introduced analysis can be used to investigate the sensitivity of the system performance as a function of the system configuration.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"49 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":"129280073","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.1991.188478
G. Gordos
For pitch detection, voiced/unvoiced decisions and speech/nonspeech decisions, an improved average magnitude difference function (AMDF) is described that has given promising results: adaptation improves accuracy and skeletonization speeds up computation. A novel definition of time-warped distance results in decreased error probability in speech recognition; however, no fast algorithm for its computation has yet been found. The concept of time-warped average, on the other hand, is easy to compute and results in better speech recognition score. Both improved AMDF and time-warped distance are discussed for use in the speaker identification environment.<>
{"title":"New feature extraction methods and the concept of time-warped distance in speech processing","authors":"G. Gordos","doi":"10.1109/GLOCOM.1991.188478","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188478","url":null,"abstract":"For pitch detection, voiced/unvoiced decisions and speech/nonspeech decisions, an improved average magnitude difference function (AMDF) is described that has given promising results: adaptation improves accuracy and skeletonization speeds up computation. A novel definition of time-warped distance results in decreased error probability in speech recognition; however, no fast algorithm for its computation has yet been found. The concept of time-warped average, on the other hand, is easy to compute and results in better speech recognition score. Both improved AMDF and time-warped distance are discussed for use in the speaker identification environment.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"19 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":"129940149","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.1991.188683
T. Moore, W. Krzymień
Statistical results are presented for DS3 signals crossing cascaded chains of SONET island networks, based on a computer-aided waiting time jitter accumulation model. The parameters of a phase-spreading desynchronizer circuit, necessary to control the additional jitter caused by pointer adjustments, are characterized in terms of jitter accumulation performance. Simulation results and analysis for both nondegraded and degraded network synchronization modes are given, including the effect of pointer adjustments. With special consideration given to certain phase spreading desynchronizer design parameters, the jitter accumulation characteristics for DS3 signals in SONET are well behaved for the example SONET study network.<>
{"title":"A simulation study of DS3 waiting time jitter accumulation in SONET","authors":"T. Moore, W. Krzymień","doi":"10.1109/GLOCOM.1991.188683","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188683","url":null,"abstract":"Statistical results are presented for DS3 signals crossing cascaded chains of SONET island networks, based on a computer-aided waiting time jitter accumulation model. The parameters of a phase-spreading desynchronizer circuit, necessary to control the additional jitter caused by pointer adjustments, are characterized in terms of jitter accumulation performance. Simulation results and analysis for both nondegraded and degraded network synchronization modes are given, including the effect of pointer adjustments. With special consideration given to certain phase spreading desynchronizer design parameters, the jitter accumulation characteristics for DS3 signals in SONET are well behaved for the example SONET study network.<<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":"130181607","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.1991.188445
K. Fukawa, H. Suzuki
The authors propose a novel adaptive equalization scheme which is a combination of the recursive least squares adaptive algorithm and maximum likelihood sequence estimation (RLS-MLSE). The performance of the scheme is demonstrated in frequency-selective fast fading mobile radio channels. RLS-MLSE employs a parallel estimation scheme in which the state of the channel is estimated by the Viterbi algorithm and the parameters of the channel impulse response are estimated by RLS. A simplified RLS algorithm and an extension to the diversity reception scheme are discussed. Computer simulations show that RLS-MLSE is suitable for 40-kb/s QPSK (quadrature phase shift keying) transmission in 900-MHz-band mobile radio systems, and that equalization with two-branch diversity operates up to a maximum Doppler frequency of 160 Hz.<>
{"title":"Adaptive equalization with RLS-MLSE for frequency-selective fast fading mobile radio channels","authors":"K. Fukawa, H. Suzuki","doi":"10.1109/GLOCOM.1991.188445","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188445","url":null,"abstract":"The authors propose a novel adaptive equalization scheme which is a combination of the recursive least squares adaptive algorithm and maximum likelihood sequence estimation (RLS-MLSE). The performance of the scheme is demonstrated in frequency-selective fast fading mobile radio channels. RLS-MLSE employs a parallel estimation scheme in which the state of the channel is estimated by the Viterbi algorithm and the parameters of the channel impulse response are estimated by RLS. A simplified RLS algorithm and an extension to the diversity reception scheme are discussed. Computer simulations show that RLS-MLSE is suitable for 40-kb/s QPSK (quadrature phase shift keying) transmission in 900-MHz-band mobile radio systems, and that equalization with two-branch diversity operates up to a maximum Doppler frequency of 160 Hz.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"2017 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":"128039542","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.1991.188724
Michael J Forbes, S. P. Spencer
The authors highlight many of the open challenges to fulfilment of the technical specification for TR-303. The telephone operating companies have a vision of integrated access that focuses on increased revenues at a reduced cost in a timely fashion. TR-303 is a technical solution that begins to address many of the issues embodied in this vision. While there are many technical challenges, the key to the timely introduction of TR-303 technology is compatibility with the existing investment in operations systems (OSs), local digital switches (LDSs) and digital loop carrier systems. TR-303 will begin with a core feature set that will be proven in close interaction between the LDS and the remote digital terminal. The existence of working TR-303 systems in the network, working with existing OSs, will provide a springboard for new OS functionality as well as providing a stable interface for development.<>
{"title":"Integrated access: the achievement of a vision","authors":"Michael J Forbes, S. P. Spencer","doi":"10.1109/GLOCOM.1991.188724","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188724","url":null,"abstract":"The authors highlight many of the open challenges to fulfilment of the technical specification for TR-303. The telephone operating companies have a vision of integrated access that focuses on increased revenues at a reduced cost in a timely fashion. TR-303 is a technical solution that begins to address many of the issues embodied in this vision. While there are many technical challenges, the key to the timely introduction of TR-303 technology is compatibility with the existing investment in operations systems (OSs), local digital switches (LDSs) and digital loop carrier systems. TR-303 will begin with a core feature set that will be proven in close interaction between the LDS and the remote digital terminal. The existence of working TR-303 systems in the network, working with existing OSs, will provide a springboard for new OS functionality as well as providing a stable interface for development.<<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":"125345468","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.1991.188686
M. Akamine, K. Miseki, M. Oshikiri
The authors describe improvements in the ADP-CELP (adaptive-density-pulse code-excited-linear-prediction) coder at 4 kb/s. A fractional delay was introduced to the adaptive codebook. A fast exhaustive search procedure for a uniformly distributed fractional delay was studied for the case where the delay length is shorter than the codevector's dimension. A novel method to determine the long-term predictor's gain was also used. Four methods to find the density pattern of the ADP excitation were investigated. A modified adaptive postfilter was used to improve subjective speech quality.<>
{"title":"Improvement of ADP-CELP speech coding at 4 kbits/s","authors":"M. Akamine, K. Miseki, M. Oshikiri","doi":"10.1109/GLOCOM.1991.188686","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188686","url":null,"abstract":"The authors describe improvements in the ADP-CELP (adaptive-density-pulse code-excited-linear-prediction) coder at 4 kb/s. A fractional delay was introduced to the adaptive codebook. A fast exhaustive search procedure for a uniformly distributed fractional delay was studied for the case where the delay length is shorter than the codevector's dimension. A novel method to determine the long-term predictor's gain was also used. Four methods to find the density pattern of the ADP excitation were investigated. A modified adaptive postfilter was used to improve subjective speech quality.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"55 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113973825","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.1991.188431
B. Steyaert, H. Bruneel
A statistical multiplexer with a finite number of independent and identical bursty traffic sources (users) is considered. The burstiness of the sources is modeled by describing both the active periods (during which a user generates one packet per slot) and the passive periods (during which a user does not generate any data) as geometric random variables. As a result, a correlated-arrivals queuing model for the multiplexer buffer is obtained, and it is analyzed by numerical means. Specifically, algorithms are given for the explicit derivation of the probability mass functions of the buffer contents (in packets) and the packet delay (in slots). The results indicate a very strong influence of the burstiness of the required buffer space in the multiplexer and the possible values of the packet delay, even for a given mean arrival rate per slot.<>
{"title":"An effective algorithm to calculate the distribution of the buffer contents and the packet delay in a multiplexer with bursty sources","authors":"B. Steyaert, H. Bruneel","doi":"10.1109/GLOCOM.1991.188431","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188431","url":null,"abstract":"A statistical multiplexer with a finite number of independent and identical bursty traffic sources (users) is considered. The burstiness of the sources is modeled by describing both the active periods (during which a user generates one packet per slot) and the passive periods (during which a user does not generate any data) as geometric random variables. As a result, a correlated-arrivals queuing model for the multiplexer buffer is obtained, and it is analyzed by numerical means. Specifically, algorithms are given for the explicit derivation of the probability mass functions of the buffer contents (in packets) and the packet delay (in slots). The results indicate a very strong influence of the burstiness of the required buffer space in the multiplexer and the possible values of the packet delay, even for a given mean arrival rate per slot.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"28 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":"122681401","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.1991.188438
A. Aghvami, O. Gemikonakli, S. Kato
The authors discuss the possibility of transmitting synchronous digital hierarchy (SDH) signals through two-link nonlinear satellite channels. Transmitting such high-bit-rate signals through standard 54-MHz transponder bandwidth requires the use of high-level modulation schemes. The techniques and technologies needed to make the use of 16-ary QAM (quadrature amplitude modulation) transmission feasible for future satellite communication systems are examined. It is shown that it is possible to transmit a synchronous-transport-module-level 1 (STM-1) signal through a standard 54-MHz transponder bandwidth using 16-ary QAM transmission, for the 6/4-GHz band. However, for higher frequency bands, due to high fade margins needed to achieve the high availability and performance for SDH systems, it is not practical to transmit the STM-1 signal through such standard transponder bandwidths.<>
{"title":"Transmission of SDH signals through future satellite channels using 16-ary QAM technique","authors":"A. Aghvami, O. Gemikonakli, S. Kato","doi":"10.1109/GLOCOM.1991.188438","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188438","url":null,"abstract":"The authors discuss the possibility of transmitting synchronous digital hierarchy (SDH) signals through two-link nonlinear satellite channels. Transmitting such high-bit-rate signals through standard 54-MHz transponder bandwidth requires the use of high-level modulation schemes. The techniques and technologies needed to make the use of 16-ary QAM (quadrature amplitude modulation) transmission feasible for future satellite communication systems are examined. It is shown that it is possible to transmit a synchronous-transport-module-level 1 (STM-1) signal through a standard 54-MHz transponder bandwidth using 16-ary QAM transmission, for the 6/4-GHz band. However, for higher frequency bands, due to high fade margins needed to achieve the high availability and performance for SDH systems, it is not practical to transmit the STM-1 signal through such standard transponder bandwidths.<<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":"121083941","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.1991.188358
Yawpo Yang, S. Soliman
The authors report a novel moments-based classifier to classify MPSK (M-ary phase shift keying) signals by using the moments of the phase utilizing the exact phase distribution. When compared with a case in which the Tikhonov function is used to approximate the asymptotic distribution of the phase, the new classifier with 1024 samples offered a 2 dB improvement. The 2 dB improvement is offered when the probability of misclassification is 0.01. Furthermore, improvement in performance can be obtained by increasing the length of the observation interval.<>
{"title":"Statistical moments based classifier for MPSK signals","authors":"Yawpo Yang, S. Soliman","doi":"10.1109/GLOCOM.1991.188358","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188358","url":null,"abstract":"The authors report a novel moments-based classifier to classify MPSK (M-ary phase shift keying) signals by using the moments of the phase utilizing the exact phase distribution. When compared with a case in which the Tikhonov function is used to approximate the asymptotic distribution of the phase, the new classifier with 1024 samples offered a 2 dB improvement. The 2 dB improvement is offered when the probability of misclassification is 0.01. Furthermore, improvement in performance can be obtained by increasing the length of the observation interval.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"99 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":"127328847","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.1991.188617
S. Konidaris
The European Commission has launched the RACE programme (Research and Development in Advanced Communications in Europe) as a key element of the European telecommunications policy. Through cooperation around joint R and D projects, the main parties (telecommunications operators, industry, service providers, users, etc.) define and share the objectives for the use of advanced telecommunications networks and services for 1995 and beyond. The status of the programme and its future orientation are presented.<>
{"title":"The RACE programme-research for advanced communications in Europe","authors":"S. Konidaris","doi":"10.1109/GLOCOM.1991.188617","DOIUrl":"https://doi.org/10.1109/GLOCOM.1991.188617","url":null,"abstract":"The European Commission has launched the RACE programme (Research and Development in Advanced Communications in Europe) as a key element of the European telecommunications policy. Through cooperation around joint R and D projects, the main parties (telecommunications operators, industry, service providers, users, etc.) define and share the objectives for the use of advanced telecommunications networks and services for 1995 and beyond. The status of the programme and its future orientation are presented.<<ETX>>","PeriodicalId":343080,"journal":{"name":"IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record","volume":"103 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":"129183170","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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