The ATM Forum is currently in the process of adopting an end-to-end adaptive rate based control scheme to support a class of best effort service known as available bit rate service (ABR). This is a reactive control method where the source rate adapts to the state of the network based on the feedback it receives from the network. The performance of such reactive feedback control schemes are sensitive to the latency in the feedback loop. In wide area networks the virtual channels traversing large hops can have very poor performance because of large propagation delays. We show that the performance of virtual channels (VCs) traversing a large number of hops in WANs can be substantially improved by giving priority to network transit traffic over traffic entering the network. We investigate the performance of the control in the presence of high priority variable bit rate traffic. The study shows that the priority scheme exhibits a robust behavior and ensures a fair share of the bandwidth for all VCs, regardless of the number of hops they traverse even under extreme loading conditions.
{"title":"End-to-end adaptive rate based congestion control scheme for ABR service in wide area ATM networks","authors":"A. Kolarov, G. Ramamurthy","doi":"10.1109/ICC.1995.525153","DOIUrl":"https://doi.org/10.1109/ICC.1995.525153","url":null,"abstract":"The ATM Forum is currently in the process of adopting an end-to-end adaptive rate based control scheme to support a class of best effort service known as available bit rate service (ABR). This is a reactive control method where the source rate adapts to the state of the network based on the feedback it receives from the network. The performance of such reactive feedback control schemes are sensitive to the latency in the feedback loop. In wide area networks the virtual channels traversing large hops can have very poor performance because of large propagation delays. We show that the performance of virtual channels (VCs) traversing a large number of hops in WANs can be substantially improved by giving priority to network transit traffic over traffic entering the network. We investigate the performance of the control in the presence of high priority variable bit rate traffic. The study shows that the priority scheme exhibits a robust behavior and ensures a fair share of the bandwidth for all VCs, regardless of the number of hops they traverse even under extreme loading conditions.","PeriodicalId":241383,"journal":{"name":"Proceedings IEEE International Conference on Communications ICC '95","volume":"117 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124432303","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}
This paper deals with transmitting CCITT H.261 standard compressed moving-images (64 kbits/sec) through shadowed mobile satellite channels. Concatenated codes consisting of 8PSK trellis inner codes and Reed-Solomon (or BCH) outer codes are used to achieve large coding gains with small bandwidth expansion in the presence of frequency-nonselective slow fading. Pilot symbol-aided techniques have been found to be suitable for the transmission of digital signals over mobile satellite channels. An improved pilot symbol assisted DFALP (decision feedback adaptive linear prediction) algorithm is presented and used to estimate fading channel state information. Monte Carlo simulations show that our 40.5 kBd system yields near error free image transmission at average channel signal to noise ratio (Eb/No) between 10-13 dB over light-to-average shadowed Rician channels. The trade off between BER performance and delay due to interleaving is investigated.
{"title":"Video image transmission via mobile satellite channels","authors":"Xiaohong Wang, Yong Liu, S. Blostein","doi":"10.1109/ICC.1995.525192","DOIUrl":"https://doi.org/10.1109/ICC.1995.525192","url":null,"abstract":"This paper deals with transmitting CCITT H.261 standard compressed moving-images (64 kbits/sec) through shadowed mobile satellite channels. Concatenated codes consisting of 8PSK trellis inner codes and Reed-Solomon (or BCH) outer codes are used to achieve large coding gains with small bandwidth expansion in the presence of frequency-nonselective slow fading. Pilot symbol-aided techniques have been found to be suitable for the transmission of digital signals over mobile satellite channels. An improved pilot symbol assisted DFALP (decision feedback adaptive linear prediction) algorithm is presented and used to estimate fading channel state information. Monte Carlo simulations show that our 40.5 kBd system yields near error free image transmission at average channel signal to noise ratio (Eb/No) between 10-13 dB over light-to-average shadowed Rician channels. The trade off between BER performance and delay due to interleaving is investigated.","PeriodicalId":241383,"journal":{"name":"Proceedings IEEE International Conference on Communications ICC '95","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125898173","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}
High-speed multimedia networks using ATM technology are being planned for deployment. Until a universal ATM network is in place, we expect to see a lot of interworking of legacy LANs with ATM WANs. This paper investigates efficient interworking between these diverse technologies and more specifically, we look into the problem of controlling packet loss-rates of multimedia informations on an end-to-end basis. We present an intelligent buffer management algorithm which would operate within the real-time usage parameter control paradigm of an ATM switch. We show that inspite of forward error correction recovery schemes, this kind of buffer management can increase raw throughput in situations where retransmission is either too costly or not possible. Preliminary simulation have yielded encouraging results.
{"title":"Increasing multimedia traffic throughput in high-speed WAN's using buffer management","authors":"S. Chatterjee, M. Bassiouni","doi":"10.1109/ICC.1995.524218","DOIUrl":"https://doi.org/10.1109/ICC.1995.524218","url":null,"abstract":"High-speed multimedia networks using ATM technology are being planned for deployment. Until a universal ATM network is in place, we expect to see a lot of interworking of legacy LANs with ATM WANs. This paper investigates efficient interworking between these diverse technologies and more specifically, we look into the problem of controlling packet loss-rates of multimedia informations on an end-to-end basis. We present an intelligent buffer management algorithm which would operate within the real-time usage parameter control paradigm of an ATM switch. We show that inspite of forward error correction recovery schemes, this kind of buffer management can increase raw throughput in situations where retransmission is either too costly or not possible. Preliminary simulation have yielded encouraging results.","PeriodicalId":241383,"journal":{"name":"Proceedings IEEE International Conference on Communications ICC '95","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127152289","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}
Orthogonal frequency division multiplexing (OFDM) is considered as an effective technique for high speed digital transmission under multipath fading. We theoretically analyze the behaviour of a coherent pilot-symbol aided M-QAM-OFDM system in the presence of a time selective multipath channel. In the analyzed scheme, pilot symbols are periodically inserted to monitor the channel characteristics. The fading process experienced by the pilot symbols is used to estimate the fade characteristics at the symbol-rate through interpolation. The estimated channel is used to compensate for the random phase variation caused by the Doppler spread, so that the signal can be coherently demodulated. The bit error rate (BER) performance of this coherent OFDM modulation scheme is derived. The results obtained show that, with a reasonable amount of redundancy (frequency of the pilot symbols) introduced, the system performance approaches that of the ideal coherent demodulation, as long as a suitable channel estimate procedure is adopted.
{"title":"Bit error rate performances of M-QAM orthogonal multicarrier modulation in presence of time-selective multipath fading","authors":"G. Santella","doi":"10.1109/ICC.1995.524487","DOIUrl":"https://doi.org/10.1109/ICC.1995.524487","url":null,"abstract":"Orthogonal frequency division multiplexing (OFDM) is considered as an effective technique for high speed digital transmission under multipath fading. We theoretically analyze the behaviour of a coherent pilot-symbol aided M-QAM-OFDM system in the presence of a time selective multipath channel. In the analyzed scheme, pilot symbols are periodically inserted to monitor the channel characteristics. The fading process experienced by the pilot symbols is used to estimate the fade characteristics at the symbol-rate through interpolation. The estimated channel is used to compensate for the random phase variation caused by the Doppler spread, so that the signal can be coherently demodulated. The bit error rate (BER) performance of this coherent OFDM modulation scheme is derived. The results obtained show that, with a reasonable amount of redundancy (frequency of the pilot symbols) introduced, the system performance approaches that of the ideal coherent demodulation, as long as a suitable channel estimate procedure is adopted.","PeriodicalId":241383,"journal":{"name":"Proceedings IEEE International Conference on Communications ICC '95","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129084875","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}
An overview of an experimental environment capable to support distance learning sessions is presented. In particular, the system described consists of specially equipped classrooms located in three Italian towns and linked by digital communication facilities, through which lectures are transmitted in real time in an interactive multimedia framework. Results of a three-year period of experiments with real university lectures are presented, along with the directions for further research and possibilities of improvement.
{"title":"A testbed for the evaluation of an interactive multimedia distance learning service","authors":"F. Davoli, P. Maryni","doi":"10.1109/ICC.1995.524450","DOIUrl":"https://doi.org/10.1109/ICC.1995.524450","url":null,"abstract":"An overview of an experimental environment capable to support distance learning sessions is presented. In particular, the system described consists of specially equipped classrooms located in three Italian towns and linked by digital communication facilities, through which lectures are transmitted in real time in an interactive multimedia framework. Results of a three-year period of experiments with real university lectures are presented, along with the directions for further research and possibilities of improvement.","PeriodicalId":241383,"journal":{"name":"Proceedings IEEE International Conference on Communications ICC '95","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126957888","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}
The principles of fuzzy logic are deployed to tackle the problem of congestion control, an issue that is of prime importance in a multiservice environment like B-ISDN. Using the leaky bucket and moving window mechanisms as building blocks, we develop a fuzzy rule-based system that is transparent to sources that, are compliant to the traffic contract, effective in shutting down noncompliant sources and quick to respond to mean and peak rate violations, as well as to peak rate violations that do not affect the mean rate, compared to the mechanisms previously proposed. The system is intuitive in concept, simple in its implementation and computationally efficient according to the restrictions imposed by the high-speed network environment it operates in.
{"title":"A fuzzy logic approach to congestion control in ATM networks","authors":"C. Douligeris, G. Develekos","doi":"10.1109/ICC.1995.524539","DOIUrl":"https://doi.org/10.1109/ICC.1995.524539","url":null,"abstract":"The principles of fuzzy logic are deployed to tackle the problem of congestion control, an issue that is of prime importance in a multiservice environment like B-ISDN. Using the leaky bucket and moving window mechanisms as building blocks, we develop a fuzzy rule-based system that is transparent to sources that, are compliant to the traffic contract, effective in shutting down noncompliant sources and quick to respond to mean and peak rate violations, as well as to peak rate violations that do not affect the mean rate, compared to the mechanisms previously proposed. The system is intuitive in concept, simple in its implementation and computationally efficient according to the restrictions imposed by the high-speed network environment it operates in.","PeriodicalId":241383,"journal":{"name":"Proceedings IEEE International Conference on Communications ICC '95","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130634770","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}
This paper evaluates a new co-channel interference cancellation technique which utilizes orthogonal convolutional codes. For code division multiple access, co-channel interference (CCI) limits its capacity. To remove this interference, several CCI cancellation techniques have been proposed, including those techniques which do not require the receiver to have knowledge of the cross-correlation between user sequences. These methods leave residual interference after the cancellation caused by errors in the initial decisions. To reduce the residual interference, the proposed scheme utilizes the error correcting capability of orthogonal convolutional codes and offers an improvement in capacity by a factor of 1.5/spl sim/3 as compared with a conventional canceller on a multipath Rayleigh fading channel.
{"title":"A co-channel interference cancellation technique using orthogonal convolutional codes on multipath Rayleigh fading channel","authors":"Y. Sanada, Qiang Wang","doi":"10.1109/ICC.1995.524224","DOIUrl":"https://doi.org/10.1109/ICC.1995.524224","url":null,"abstract":"This paper evaluates a new co-channel interference cancellation technique which utilizes orthogonal convolutional codes. For code division multiple access, co-channel interference (CCI) limits its capacity. To remove this interference, several CCI cancellation techniques have been proposed, including those techniques which do not require the receiver to have knowledge of the cross-correlation between user sequences. These methods leave residual interference after the cancellation caused by errors in the initial decisions. To reduce the residual interference, the proposed scheme utilizes the error correcting capability of orthogonal convolutional codes and offers an improvement in capacity by a factor of 1.5/spl sim/3 as compared with a conventional canceller on a multipath Rayleigh fading channel.","PeriodicalId":241383,"journal":{"name":"Proceedings IEEE International Conference on Communications ICC '95","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132147409","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}
Three different types of structures for nonlinear equalizers are discussed to reduce nonlinear distortion in digital high-density recording channels. The first two equalizers, a nonlinear DFE and a modified version of partial response maximum likelihood (PRML) with a nonlinear equalizer, which are based on the pth-order inverse theorem of Volterra series, can reduce the nonlinear ISI existing in both precursor and postcursor parts. The last one, a nonlinear canceller with an appropriate tentative decision device, can further cancel the cross products between the previous and future symbols without producing higher-order terms (/spl ges/p+1). By comparing their performances via simulation with the existing LE, linear DFE, RAM-DFE, and PRML for digital recording channels with three different densities, the authors confirm that the nonlinear ISI can be reduced effectively by the approaches discussed in the paper especially at higher densities.
{"title":"Nonlinear equalization for reduction of nonlinear distortion in high-density recording channels","authors":"W. Jeon, J. S. Son, Y. Cho, Y. Lim, D. Youn","doi":"10.1109/ICC.1995.525220","DOIUrl":"https://doi.org/10.1109/ICC.1995.525220","url":null,"abstract":"Three different types of structures for nonlinear equalizers are discussed to reduce nonlinear distortion in digital high-density recording channels. The first two equalizers, a nonlinear DFE and a modified version of partial response maximum likelihood (PRML) with a nonlinear equalizer, which are based on the pth-order inverse theorem of Volterra series, can reduce the nonlinear ISI existing in both precursor and postcursor parts. The last one, a nonlinear canceller with an appropriate tentative decision device, can further cancel the cross products between the previous and future symbols without producing higher-order terms (/spl ges/p+1). By comparing their performances via simulation with the existing LE, linear DFE, RAM-DFE, and PRML for digital recording channels with three different densities, the authors confirm that the nonlinear ISI can be reduced effectively by the approaches discussed in the paper especially at higher densities.","PeriodicalId":241383,"journal":{"name":"Proceedings IEEE International Conference on Communications ICC '95","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130423075","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}
The traffic carried by common channel signalling (CCS) networks is continually increasing. This, coupled with increasing complexity in services and customer profiles, results in potentially volatile traffic, and can lead to overload in various components of the CCS network. This paper investigates the dynamics of the national option with congestion priorities (NOCP) and international option (IO) congestion control strategies, when they are implemented in a CCS network during a period of signalling transfer point (STP) processor overload. In addition, we study the success of a combined control (CC) which incorporates both the NOCP and IO. We find (1) IO performs well under all the situations studied, and (2) the NOCP performs well in most cases, but is sensitive to the setting of congestion thresholds.
{"title":"An investigation of congestion dynamics in CCS networks during STP processor overload","authors":"B. Northcote, M. Rumsewicz","doi":"10.1109/ICC.1995.525151","DOIUrl":"https://doi.org/10.1109/ICC.1995.525151","url":null,"abstract":"The traffic carried by common channel signalling (CCS) networks is continually increasing. This, coupled with increasing complexity in services and customer profiles, results in potentially volatile traffic, and can lead to overload in various components of the CCS network. This paper investigates the dynamics of the national option with congestion priorities (NOCP) and international option (IO) congestion control strategies, when they are implemented in a CCS network during a period of signalling transfer point (STP) processor overload. In addition, we study the success of a combined control (CC) which incorporates both the NOCP and IO. We find (1) IO performs well under all the situations studied, and (2) the NOCP performs well in most cases, but is sensitive to the setting of congestion thresholds.","PeriodicalId":241383,"journal":{"name":"Proceedings IEEE International Conference on Communications ICC '95","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125397594","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}
Lossy video compression algorithms, such as those used in the H.261 and MPEG standards, result in quality degradation seen in the form of tiling, edge business, and mosquito noise. The number of bits required to encode a scene so as to achieve a given quality objective depends on the scene content; the more complex the scene is, the more bits are required. Therefore, in order to achieve a given video quality at all times, the encoder parameters must be appropriately adjusted according to the scene content. The authors propose a video encoding scheme which maintains the quality of the encoded video at a constant level. This scheme is based on a quantitative video quality measure, and it uses a feedback control mechanism to control the parameters of the encoder. The authors evaluate this scheme by applying it to test sequences, and compare it with constant bit rate and open-loop variable bit rate schemes in terms of quality and rate. They show that their scheme achieves better quality than the other two schemes for a given total number of bits, particularly when the content has scene changes over time.
{"title":"Constant quality video encoding","authors":"Ismail Dalggg, F. Tobagi","doi":"10.1109/ICC.1995.524300","DOIUrl":"https://doi.org/10.1109/ICC.1995.524300","url":null,"abstract":"Lossy video compression algorithms, such as those used in the H.261 and MPEG standards, result in quality degradation seen in the form of tiling, edge business, and mosquito noise. The number of bits required to encode a scene so as to achieve a given quality objective depends on the scene content; the more complex the scene is, the more bits are required. Therefore, in order to achieve a given video quality at all times, the encoder parameters must be appropriately adjusted according to the scene content. The authors propose a video encoding scheme which maintains the quality of the encoded video at a constant level. This scheme is based on a quantitative video quality measure, and it uses a feedback control mechanism to control the parameters of the encoder. The authors evaluate this scheme by applying it to test sequences, and compare it with constant bit rate and open-loop variable bit rate schemes in terms of quality and rate. They show that their scheme achieves better quality than the other two schemes for a given total number of bits, particularly when the content has scene changes over time.","PeriodicalId":241383,"journal":{"name":"Proceedings IEEE International Conference on Communications ICC '95","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126273376","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：