The Experts below are selected from a list of 165 Experts worldwide ranked by ideXlab platform
Philippe Martins - One of the best experts on this subject based on the ideXlab platform.
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a tcp connection over uplink umts radio access bearer in rlc Acknowledged Mode
Vehicular Technology Conference, 2002Co-Authors: R Bestak, Philippe Godlewski, Philippe MartinsAbstract:Integration of cellular networks into the existing Internet world gives rise to some problems, mainly for the reason that protocol mechanisms defined and optimized for wired networks do not perform well when they are directly applied in wireless networks. In this paper we study an uplink TCP connection over the UMTS radio interface, when using a RLC entity in Acknowledged Mode. We suggest the introduction between TCP and RLC protocols of a specific mechanism called early error notification. Via this mechanism, a TCP sender is informed whenever a data segment is virtually discarded at the RLC level. Thus, a TCP sender detects in advance a segment loss at the RLC level without waiting for three duplicated acknowledgments or a timeout event.
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Interactions between the TCP and RLC Protocols in UMTS
Multiaccess Mobility and Teletraffic for Wireless Communications volume 6, 2002Co-Authors: R Bestak, Philippe Godlewski, Philippe MartinsAbstract:Congestion control mechanisms, used in TCP, suffer from some performance issues when using them over wireless links. In this paper we investigate a TCP connection over the UMTS radio interface when using the RLC protocol in Acknowledged Mode. We compare protocol mechanisms used in TCP and RLC. The influence of the TCP congestion control mechanisms on the RLC buffer occupancy is analyzed and interactions between these two protocols are investigated.
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VTC Spring - A TCP connection over uplink UMTS radio access bearer in RLC Acknowledged Mode
Vehicular Technology Conference. IEEE 55th Vehicular Technology Conference. VTC Spring 2002 (Cat. No.02CH37367), 1Co-Authors: R Bestak, Philippe Godlewski, Philippe MartinsAbstract:Integration of cellular networks into the existing Internet world gives rise to some problems, mainly for the reason that protocol mechanisms defined and optimized for wired networks do not perform well when they are directly applied in wireless networks. In this paper we study an uplink TCP connection over the UMTS radio interface, when using a RLC entity in Acknowledged Mode. We suggest the introduction between TCP and RLC protocols of a specific mechanism called early error notification. Via this mechanism, a TCP sender is informed whenever a data segment is virtually discarded at the RLC level. Thus, a TCP sender detects in advance a segment loss at the RLC level without waiting for three duplicated acknowledgments or a timeout event.
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PIMRC - RLC buffer occupancy when using a TCP connection over UMTS
The 13th IEEE International Symposium on Personal Indoor and Mobile Radio Communications, 1Co-Authors: R Bestak, Philippe Godlewski, Philippe MartinsAbstract:This paper analyzes a TCP connection over UMTS radio access bearer in RLC Acknowledged Mode. The stacking of RLC and TCP protocols is highly beneficial for the global system behavior. Protocol mechanisms used by RLC are well adapted to wireless constraints and the ARQ function implemented by RLC hides the wireless channel unreliability to TCP. However, RLC protocol parameters have to be carefully tuned otherwise the TCP performance can degrade due to RLC. One of the factors that can influence the TCP performance is the RLC buffer size. We analyzed some of factors that affect the RLC buffer occupancy and we show that an insufficient buffer size degrades the TCP performance.
R Bestak - One of the best experts on this subject based on the ideXlab platform.
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a tcp connection over uplink umts radio access bearer in rlc Acknowledged Mode
Vehicular Technology Conference, 2002Co-Authors: R Bestak, Philippe Godlewski, Philippe MartinsAbstract:Integration of cellular networks into the existing Internet world gives rise to some problems, mainly for the reason that protocol mechanisms defined and optimized for wired networks do not perform well when they are directly applied in wireless networks. In this paper we study an uplink TCP connection over the UMTS radio interface, when using a RLC entity in Acknowledged Mode. We suggest the introduction between TCP and RLC protocols of a specific mechanism called early error notification. Via this mechanism, a TCP sender is informed whenever a data segment is virtually discarded at the RLC level. Thus, a TCP sender detects in advance a segment loss at the RLC level without waiting for three duplicated acknowledgments or a timeout event.
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Interactions between the TCP and RLC Protocols in UMTS
Multiaccess Mobility and Teletraffic for Wireless Communications volume 6, 2002Co-Authors: R Bestak, Philippe Godlewski, Philippe MartinsAbstract:Congestion control mechanisms, used in TCP, suffer from some performance issues when using them over wireless links. In this paper we investigate a TCP connection over the UMTS radio interface when using the RLC protocol in Acknowledged Mode. We compare protocol mechanisms used in TCP and RLC. The influence of the TCP congestion control mechanisms on the RLC buffer occupancy is analyzed and interactions between these two protocols are investigated.
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VTC Spring - A TCP connection over uplink UMTS radio access bearer in RLC Acknowledged Mode
Vehicular Technology Conference. IEEE 55th Vehicular Technology Conference. VTC Spring 2002 (Cat. No.02CH37367), 1Co-Authors: R Bestak, Philippe Godlewski, Philippe MartinsAbstract:Integration of cellular networks into the existing Internet world gives rise to some problems, mainly for the reason that protocol mechanisms defined and optimized for wired networks do not perform well when they are directly applied in wireless networks. In this paper we study an uplink TCP connection over the UMTS radio interface, when using a RLC entity in Acknowledged Mode. We suggest the introduction between TCP and RLC protocols of a specific mechanism called early error notification. Via this mechanism, a TCP sender is informed whenever a data segment is virtually discarded at the RLC level. Thus, a TCP sender detects in advance a segment loss at the RLC level without waiting for three duplicated acknowledgments or a timeout event.
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PIMRC - RLC buffer occupancy when using a TCP connection over UMTS
The 13th IEEE International Symposium on Personal Indoor and Mobile Radio Communications, 1Co-Authors: R Bestak, Philippe Godlewski, Philippe MartinsAbstract:This paper analyzes a TCP connection over UMTS radio access bearer in RLC Acknowledged Mode. The stacking of RLC and TCP protocols is highly beneficial for the global system behavior. Protocol mechanisms used by RLC are well adapted to wireless constraints and the ARQ function implemented by RLC hides the wireless channel unreliability to TCP. However, RLC protocol parameters have to be carefully tuned otherwise the TCP performance can degrade due to RLC. One of the factors that can influence the TCP performance is the RLC buffer size. We analyzed some of factors that affect the RLC buffer occupancy and we show that an insufficient buffer size degrades the TCP performance.
Philippe Godlewski - One of the best experts on this subject based on the ideXlab platform.
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a tcp connection over uplink umts radio access bearer in rlc Acknowledged Mode
Vehicular Technology Conference, 2002Co-Authors: R Bestak, Philippe Godlewski, Philippe MartinsAbstract:Integration of cellular networks into the existing Internet world gives rise to some problems, mainly for the reason that protocol mechanisms defined and optimized for wired networks do not perform well when they are directly applied in wireless networks. In this paper we study an uplink TCP connection over the UMTS radio interface, when using a RLC entity in Acknowledged Mode. We suggest the introduction between TCP and RLC protocols of a specific mechanism called early error notification. Via this mechanism, a TCP sender is informed whenever a data segment is virtually discarded at the RLC level. Thus, a TCP sender detects in advance a segment loss at the RLC level without waiting for three duplicated acknowledgments or a timeout event.
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Interactions between the TCP and RLC Protocols in UMTS
Multiaccess Mobility and Teletraffic for Wireless Communications volume 6, 2002Co-Authors: R Bestak, Philippe Godlewski, Philippe MartinsAbstract:Congestion control mechanisms, used in TCP, suffer from some performance issues when using them over wireless links. In this paper we investigate a TCP connection over the UMTS radio interface when using the RLC protocol in Acknowledged Mode. We compare protocol mechanisms used in TCP and RLC. The influence of the TCP congestion control mechanisms on the RLC buffer occupancy is analyzed and interactions between these two protocols are investigated.
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VTC Spring - A TCP connection over uplink UMTS radio access bearer in RLC Acknowledged Mode
Vehicular Technology Conference. IEEE 55th Vehicular Technology Conference. VTC Spring 2002 (Cat. No.02CH37367), 1Co-Authors: R Bestak, Philippe Godlewski, Philippe MartinsAbstract:Integration of cellular networks into the existing Internet world gives rise to some problems, mainly for the reason that protocol mechanisms defined and optimized for wired networks do not perform well when they are directly applied in wireless networks. In this paper we study an uplink TCP connection over the UMTS radio interface, when using a RLC entity in Acknowledged Mode. We suggest the introduction between TCP and RLC protocols of a specific mechanism called early error notification. Via this mechanism, a TCP sender is informed whenever a data segment is virtually discarded at the RLC level. Thus, a TCP sender detects in advance a segment loss at the RLC level without waiting for three duplicated acknowledgments or a timeout event.
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PIMRC - RLC buffer occupancy when using a TCP connection over UMTS
The 13th IEEE International Symposium on Personal Indoor and Mobile Radio Communications, 1Co-Authors: R Bestak, Philippe Godlewski, Philippe MartinsAbstract:This paper analyzes a TCP connection over UMTS radio access bearer in RLC Acknowledged Mode. The stacking of RLC and TCP protocols is highly beneficial for the global system behavior. Protocol mechanisms used by RLC are well adapted to wireless constraints and the ARQ function implemented by RLC hides the wireless channel unreliability to TCP. However, RLC protocol parameters have to be carefully tuned otherwise the TCP performance can degrade due to RLC. One of the factors that can influence the TCP performance is the RLC buffer size. We analyzed some of factors that affect the RLC buffer occupancy and we show that an insufficient buffer size degrades the TCP performance.
Guillaume Grao - One of the best experts on this subject based on the ideXlab platform.
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Experimental evaluation of WebRTC voice quality in LTE coverage tests
2017Co-Authors: Najmeddine Majed, Alberto Blanc, Jerome Dufour, Stéphane Ragot, Xavier Lagrange, Guillaume GraoAbstract:In this paper, we present experimental results on WebRTC voice quality as a function of LTE radio coverage. Different LTE radio conditions were tested by varying the radio path loss (with fast fading) in controlled test lab conditions. Voice quality was evaluated at different speech coding bit rates in terms of POLQA score and mouth-to-ear delay. Results show that, with Acknowledged Mode data transmission over LTE, degrading radio 8 coverage translated mainly into increasing end-to-end delay and 9 jitter, with virtually no packet loss up to the coverage limit. Voice 10 quality is analyzed by studying the influence of the specific jitter 11 buffer used in WebRTC endpoints.
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QoMEX - Experimental evaluation of WebRTC voice quality in LTE coverage tests
2017 Ninth International Conference on Quality of Multimedia Experience (QoMEX), 2017Co-Authors: Najmeddine Majed, Alberto Blanc, Stéphane Ragot, Xavier Lagrange, Jercome Dufour, Guillaume GraoAbstract:In this paper, we present experimental results on WebRTC voice quality as a function of LTE radio coverage. Different LTE radio conditions were tested by varying the radio path loss (with fast fading) in controlled test lab conditions. Voice quality was evaluated at different speech coding bit rates in terms of POLQA score and mouth-to-ear delay. Results show that, with Acknowledged Mode (AM) data transmission over LTE, degraded radio coverage translate essentially into increased end-to-end delay and jitter, with virtually no packet loss up to the coverage limit. Voice quality is analyzed by studying the influence of the specific jitter buffer used in WebRTC endpoints.
Barry G. Evans - One of the best experts on this subject based on the ideXlab platform.
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Performance analysis of session initiation protocol based call set-up over satellite-UMTS network
Computer Communications, 2005Co-Authors: V.y.h. Kueh, Rahim Tafazolli, Barry G. EvansAbstract:Session Initiation Protocol (SIP) has been selected as the official end-to-end signalling protocol for establishing multimedia sessions in the IP-based Universal Mobile Telecommunication Systems (UMTS) network. Since a satellite component has been identified to play an integral role in UMTS, there is a need also to support SIP-based session establishment over Satellite-UMTS (S-UMTS) to achieve end-to-end seamless IP-based terrestrial/satellite network integration. However, the transport of SIP over the satellite radio interface is not efficient due to the request/response nature of SIP and its large message size, coupled with the unreliable wireless links and the larger propagation delay. With little work carried out in this area, this paper presents the research on the efficient solutions to transport SIP session set-up signalling over the S-UMTS radio interface based on the Radio Link Control Acknowledged Mode (RLC-AM) mechanisms. Two schemes are also proposed to overcome the inefficiency of the current RLC-AM procedure when applied for session set-up over S-UMTS. The proposed enhancements are easy to implement and are fully backward compatible with the existing implementation of RLC-AM in UMTS.
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On the Interaction Between SIP and RLC Error Recovery in Session Establishment Over Satellite-UMTS
22nd AIAA International Communications Satellite Systems Conference & Exhibit 2004 (ICSSC), 2004Co-Authors: V.y.h. Kueh, Rahim Tafazolli, Barry G. EvansAbstract:The transport of SIP signaling for session establishment over the satellite radio interface is not efficient due to the inherent characteristics of SIP coupled with the unreliable wireless links and the larger satellite propagation delay. One way to improve the session set-up performance is to conceal the link-related losses from the upper layers by utilizing link layer retransmission based on the UMTS Radio Link Control Acknowledged Mode (RLC-AM) mechanisms. Nevertheless, due to link layer protocols operating independently from higher layer protocol, the interaction between the link-layer transmission and end-to-end transmission can become complicated and this may lead to poor system performance and resource utilization if the setting of timers at the two layers is incompatible. In this paper, we investigate the problem of the possible competing error recovery between the end-to-end retransmissions implemented at the higher layers with the local retransmissions at the lower layers. More specifically, we look into the interaction between the session layer (SIP) own reliability mechanisms with the link layer (RLC) retransmission scheme, and study different schemes to minimize the undesirable effect of both layers responding to the same loss events. This is made possible by making SIP and RLC to be ‘more co-operative’ through different degree of awareness between these two error recovery schemes.
