9783958860476 - voip performance of lte networks: volte versus ott (aachener beiträge zur mobil- und telekommunikation series) di mühleisen; maciej grzegorz; dr; ph.d. (14 risultati)
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Paperback. Condizione: new. Paperback. Long Term Evolution (LTE) standardized by 3GPP operates fully packet switched and does not have a circuit switched domain as older systems HSPA, UMTS and GSM. It must support a minimum number of voice calls to be recognized as IMT-Advanced system by ITU. Therefore ITU has published the IMT-…Advanced Evaluation Guidelines describing evaluation scenarios and minimum quality of service demands for voice calls to be evaluated by system level simulation. Those guidelines require transmission of VoIP packets within 50 ms over the air interface and packet loss rate below 2 %.3GPP came to the conclusion Voice-over-LTE (VoLTE) with semi-persistent scheduling satisfies the ITU demands. This was verified by independent evaluation groups. Semi-persistent scheduling reserves radio resources for VoIP packets for the duration of a talk spurt while other packets, e.g. retransmissions of lost packets, individually receive resources (dynamic scheduling). Advantage is significantly decreased signaling overhead but the method is more complex than the classical approach individually assigning radio resources for each packet. Individual assignment of radio resources is also used for data traffic of so called Over-the-Top (OTT) VoIP applications.This thesis compares VoIP capacity of VoLTE and OTT focusing on the impact of the radio link. Radio resource assignment optimized for delay critical traffic like VoIP is assumed for OTT to allow a fair comparison. A concept developed by me to design complex VoIP schedulers from basic resource assignment algorithms is described. It is applied for VoLTE and OTT. The openWNS/IMTAPhy simulator developed at RWTH Aachen University ComNets Research Group and extended at TU Munich Chair of Communication Networks is enhanced for VoIP evaluation based on that concept. Methods to improve VoIP capacity are evaluated separately for up- and downlink. Different channel prediction strategies are applied for each direction and based on that transmission rate adaptation is performed.Results show improved capacity through aggressive rate adaptation and resource assignment resulting in higher data rates and therefore reduced resource demand while at the same time increasing packet error rate. Too aggressive parameters significantly reduce VoIP capacity while moderate adjustments increase it by ca. 15 % in the downlink and 10 % in the uplink for VoLTE. OTT cannot benefit from these improvements if the number of control channels is limited and becomes a bottleneck. If more control channels were available than defined by the current standard OTT VoIP capacity could be improved for downlink. High uplink interference variance makes channel prediction more difficult and prevents capacity gains for OTT as achieved with VoLTE.Besides simulation results an analytical discrete time Engset queueing model was described and solved for its waiting time distribution to determine VoIP capacity in scenarios without and with adjacent channel interference from neighbor cells.In the Urban Macrocell scenario lowest downlink VoIP capacity results 43 users / cell / MHz for OTT and 41 users / cell / MHz for VoLTE were obtained with unlimited number of control channels. The Downlink is the bottleneck and therefore determines the overall VoIP capacity. Allowing users with bad channel condition to transmit at higher data rates than suggested by the rate adaptation algorithm reduces resource occupation but at the same time increases packet error rate. VoIP capacity is increased to 48 and 47 users / cell / MHz this way for OTT and VolTE, respectively.From this it is concluded that dynamic scheduling used by OTT is capable to provide sufficient VoIP capacity without the complexity introduced by SPS given that sufficient control channels are available, as expected in reality. Shipping may be from multiple locations in the US or from the UK, depending on stock availability.
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Paperback. Condizione: New. Long Term Evolution (LTE) standardized by 3GPP operates fully packet switched and does not have a circuit switched domain as older systems HSPA, UMTS and GSM. It must support a minimum number of voice calls to be recognized as IMT-Advanced system by ITU. Therefore ITU has published the IMT-Advanced Ev…aluation Guidelines describing evaluation scenarios and minimum quality of service demands for voice calls to be evaluated by system level simulation. Those guidelines require transmission of VoIP packets within 50 ms over the air interface and packet loss rate below 2 %.3GPP came to the conclusion Voice-over-LTE (VoLTE) with semi-persistent scheduling satisfies the ITU demands. This was verified by independent evaluation groups. Semi-persistent scheduling reserves radio resources for VoIP packets for the duration of a talk spurt while other packets, e.g. retransmissions of lost packets, individually receive resources (dynamic scheduling). Advantage is significantly decreased signaling overhead but the method is more complex than the classical approach individually assigning radio resources for each packet. Individual assignment of radio resources is also used for data traffic of so called Over-the-Top (OTT) VoIP applications.This thesis compares VoIP capacity of VoLTE and OTT focusing on the impact of the radio link. Radio resource assignment optimized for delay critical traffic like VoIP is assumed for OTT to allow a fair comparison. A concept developed by me to design complex VoIP schedulers from basic resource assignment algorithms is described. It is applied for VoLTE and OTT. The openWNS/IMTAPhy simulator developed at RWTH Aachen University ComNets Research Group and extended at TU Munich Chair of Communication Networks is enhanced for VoIP evaluation based on that concept. Methods to improve VoIP capacity are evaluated separately for up- and downlink. Different channel prediction strategies are applied for each direction and based on that transmission rate adaptation is performed.Results show improved capacity through aggressive rate adaptation and resource assignment resulting in higher data rates and therefore reduced resource demand while at the same time increasing packet error rate. Too aggressive parameters significantly reduce VoIP capacity while moderate adjustments increase it by ca. 15 % in the downlink and 10 % in the uplink for VoLTE. OTT cannot benefit from these improvements if the number of control channels is limited and becomes a bottleneck. If more control channels were available than defined by the current standard OTT VoIP capacity could be improved for downlink. High uplink interference variance makes channel prediction more difficult and prevents capacity gains for OTT as achieved with VoLTE.Besides simulation results an analytical discrete time Engset queueing model was described and solved for its waiting time distribution to determine VoIP capacity in scenarios without and with adjacent channel interference from neighb.
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Paperback. Condizione: new. Paperback. Long Term Evolution (LTE) standardized by 3GPP operates fully packet switched and does not have a circuit switched domain as older systems HSPA, UMTS and GSM. It must support a minimum number of voice calls to be recognized as IMT-Advanced system by ITU. Therefore ITU has published the IMT-…Advanced Evaluation Guidelines describing evaluation scenarios and minimum quality of service demands for voice calls to be evaluated by system level simulation. Those guidelines require transmission of VoIP packets within 50 ms over the air interface and packet loss rate below 2 %.3GPP came to the conclusion Voice-over-LTE (VoLTE) with semi-persistent scheduling satisfies the ITU demands. This was verified by independent evaluation groups. Semi-persistent scheduling reserves radio resources for VoIP packets for the duration of a talk spurt while other packets, e.g. retransmissions of lost packets, individually receive resources (dynamic scheduling). Advantage is significantly decreased signaling overhead but the method is more complex than the classical approach individually assigning radio resources for each packet. Individual assignment of radio resources is also used for data traffic of so called Over-the-Top (OTT) VoIP applications.This thesis compares VoIP capacity of VoLTE and OTT focusing on the impact of the radio link. Radio resource assignment optimized for delay critical traffic like VoIP is assumed for OTT to allow a fair comparison. A concept developed by me to design complex VoIP schedulers from basic resource assignment algorithms is described. It is applied for VoLTE and OTT. The openWNS/IMTAPhy simulator developed at RWTH Aachen University ComNets Research Group and extended at TU Munich Chair of Communication Networks is enhanced for VoIP evaluation based on that concept. Methods to improve VoIP capacity are evaluated separately for up- and downlink. Different channel prediction strategies are applied for each direction and based on that transmission rate adaptation is performed.Results show improved capacity through aggressive rate adaptation and resource assignment resulting in higher data rates and therefore reduced resource demand while at the same time increasing packet error rate. Too aggressive parameters significantly reduce VoIP capacity while moderate adjustments increase it by ca. 15 % in the downlink and 10 % in the uplink for VoLTE. OTT cannot benefit from these improvements if the number of control channels is limited and becomes a bottleneck. If more control channels were available than defined by the current standard OTT VoIP capacity could be improved for downlink. High uplink interference variance makes channel prediction more difficult and prevents capacity gains for OTT as achieved with VoLTE.Besides simulation results an analytical discrete time Engset queueing model was described and solved for its waiting time distribution to determine VoIP capacity in scenarios without and with adjacent channel interference from neighbor cells.In the Urban Macrocell scenario lowest downlink VoIP capacity results 43 users / cell / MHz for OTT and 41 users / cell / MHz for VoLTE were obtained with unlimited number of control channels. The Downlink is the bottleneck and therefore determines the overall VoIP capacity. Allowing users with bad channel condition to transmit at higher data rates than suggested by the rate adaptation algorithm reduces resource occupation but at the same time increases packet error rate. VoIP capacity is increased to 48 and 47 users / cell / MHz this way for OTT and VolTE, respectively.From this it is concluded that dynamic scheduling used by OTT is capable to provide sufficient VoIP capacity without the complexity introduced by SPS given that sufficient control channels are available, as expected in reality. Shipping may be from our Sydney, NSW warehouse or from our UK or US warehouse, depending on stock availability.
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Da: Rarewaves.com UK, London, Regno UnitoRarewaves.com UK
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Paperback. Condizione: New. Long Term Evolution (LTE) standardized by 3GPP operates fully packet switched and does not have a circuit switched domain as older systems HSPA, UMTS and GSM. It must support a minimum number of voice calls to be recognized as IMT-Advanced system by ITU. Therefore ITU has published the IMT-Advanced Ev…aluation Guidelines describing evaluation scenarios and minimum quality of service demands for voice calls to be evaluated by system level simulation. Those guidelines require transmission of VoIP packets within 50 ms over the air interface and packet loss rate below 2 %.3GPP came to the conclusion Voice-over-LTE (VoLTE) with semi-persistent scheduling satisfies the ITU demands. This was verified by independent evaluation groups. Semi-persistent scheduling reserves radio resources for VoIP packets for the duration of a talk spurt while other packets, e.g. retransmissions of lost packets, individually receive resources (dynamic scheduling). Advantage is significantly decreased signaling overhead but the method is more complex than the classical approach individually assigning radio resources for each packet. Individual assignment of radio resources is also used for data traffic of so called Over-the-Top (OTT) VoIP applications.This thesis compares VoIP capacity of VoLTE and OTT focusing on the impact of the radio link. Radio resource assignment optimized for delay critical traffic like VoIP is assumed for OTT to allow a fair comparison. A concept developed by me to design complex VoIP schedulers from basic resource assignment algorithms is described. It is applied for VoLTE and OTT. The openWNS/IMTAPhy simulator developed at RWTH Aachen University ComNets Research Group and extended at TU Munich Chair of Communication Networks is enhanced for VoIP evaluation based on that concept. Methods to improve VoIP capacity are evaluated separately for up- and downlink. Different channel prediction strategies are applied for each direction and based on that transmission rate adaptation is performed.Results show improved capacity through aggressive rate adaptation and resource assignment resulting in higher data rates and therefore reduced resource demand while at the same time increasing packet error rate. Too aggressive parameters significantly reduce VoIP capacity while moderate adjustments increase it by ca. 15 % in the downlink and 10 % in the uplink for VoLTE. OTT cannot benefit from these improvements if the number of control channels is limited and becomes a bottleneck. If more control channels were available than defined by the current standard OTT VoIP capacity could be improved for downlink. High uplink interference variance makes channel prediction more difficult and prevents capacity gains for OTT as achieved with VoLTE.Besides simulation results an analytical discrete time Engset queueing model was described and solved for its waiting time distribution to determine VoIP capacity in scenarios without and with adjacent channel interference from neighb.
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Da: AHA-BUCH GmbH, Einbeck, GermaniaAHA-BUCH GmbH
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Taschenbuch. Condizione: Neu. Neuware - Das von der 3GPP standardisierte 4G Mobilfunksystem Long Term Evolution (LTE) arbeitet vollständig paketvermittelt und hat keine leitungsvermittelte Domäne mehr wie die älteren Systeme HSPA, UMTS und GSM. Um als IMT-Advanced System von der ITU Anerkannt zu werden muss es trotzdem nachweise…n, dass es eine Mindestzahl von Sprachtelefonaten unterstützt. Die ITU hat hierzu die IMT-Advanced Evaluation Guidelines veröffentlicht, in denen Bewertungsszenarien und Mindestdienstgüteanforderungen für Sprachtelefonie beschrieben sind, die mittels Systemsimulation zu bestimmen sind. Demnach müssen VoIP Pakete innerhalb von 50 ms über die Funkschnittstelle übertragen werden und der Paketverlust darf 2 % nicht überschreiten. Die 3GPP ist zum Schluss gekommen, dass Voice-over-LTE (VoLTE) unter Ausnutzung von semipersistenter Funkressourcenzuteilung die Mindestanforderungen der ITU erfüllt, was auch von unabhängigen Gutachtergruppen bestätigt wurde. Bei der semipersistenten Funkressourcenzuteilung werden Funkbetriebsmittel für VoIP Pakete für die Dauer eines Talk-Spurts reserviert während anderen Pakete, beispielsweise wiederholten Übertragungen fehlerhaft empfangener Pakete, einzeln Ressourcen zugewiesen werden. Der Vorteil ist ein deutlich reduzierter Signalisierungsaufwand, doch das Verfahren ist komplexer als der klassische Ansatz jedem Paket einzeln Funkbetriebsmittel zuzuweisen. Letzteres wird auch für den Datenverkehr von so genannten Over-the-Top (OTT) VoIP Anwendungen eingesetzt. Diese Arbeit vergleicht die VoIP Kapazität von VoLTE mit der von OTT, wobei der Schwerpunkt auf dem Einfluss der Funkschnittstelle liegt. Für einen fairen Vergleich wird angenommen, dass die Funkressourcenzuweisung für OTT für verzögerungskritische Anwendungen wie VoIP optimiert ist. Dafür wird zunächst ein von mir entwickeltes Konzept für den Entwurf komplexer VoIP Scheduler auf Basis atomarer Ressourcenzuweisungsalgorithmen beschrieben der sowohl für VoLTE als auch für OTT eingesetzt wird. Basierend hierauf wurde der bei der RWTH Aachen ComNets Forschergruppe Entwickelte und dem Lehstuhl für Kommunikationsnetze der TU München weiterentwickelte Simulator openWNS/ IMTAPhy für die VoIP Evaluation erweitert. Methoden zur Erhöhung der VoIP Kapazität werden getrennt nach Aufwärtsund Abwärtsstrecke betrachtet. Für jede Richtung werden unterschiedliche Strategien zur Prädiktion der Kanalqualität angewendet und darauf basierender Anpassung der Datenrate. Die Ergebnisse zeigen, dass Kapazitätssteigerungen insbesondere durch aggressive Ratenanpassung und Ressourcenzuweisung möglich sind. Dabei werden höhere Datenraten und somit ein geringerer Ressourcenbedarf erreicht, wobei sich gleichzeitig die Paketfehlerrate erhöht. Zu aggressive Einstellungen führen zur erheblichen Minderung der VoIP Kapazität während eine moderate Anpassung Kapazitätssteigerungen von ungefähr 15 % in der Abwärts- und 10 % in der Aufwärtsstrecke für VoLTE ermöglicht. OTT kann diese Steigerung mit begrenzter Anzahl Signalisierungskanäle nicht erreichen, die einen Engpass darstellen. Auch mit mehr Signalisierungskanälen als heute im Standard vorgesehen könnte OTT lediglich in der Abwärtsstrecke die VoIP Kapazität steigern. Die grosse Varianz der Interferenz bei OTT und die dadurch erschwerte Prädiktion der Kanalqualität verhindert Steigerungen auf der Aufwärtsstrecke, wie sie mit VoLTE möglich sind. Neben Simulationsergebnissen wurde auch ein analytisches zeitdiskretes Engset Wartemodell beschrieben und die Verteilung der Wartezeitverzögerung von diesem bestimmt, um die VoIP Kapazität im interferenzfreien Fall und bei Gleichkanalinterferenz durch Nachbarzellen zu bestimmen. Im Urban Macrocell Szenario ergibt sich die geringste VoIP Kapazität. Diese beträgt 43 Benutzer / Zelle / MHz für OTT, wenn man von einer unbeschränkten Anzahl Signalisierungskanäle ausgeht, und 41 Benutzer / Zelle / MHz für VoLTE in der Abwärtsstrecke, die den Engpass darstellt und somit die Gesamtkapazität bestimmt.
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