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Papers by Sebastian Schumann

Research paper thumbnail of Building complex Voice over IP (VoIP) applications based on open-source

2009 International Symposium Elmar, Sep 28, 2009

Research paper thumbnail of Voice over IP (VoIP) speech quality measurement with open-source software components

Proceedings Elmar 2010, Sep 15, 2010

Research paper thumbnail of Deliverable D3

Research paper thumbnail of Smart AppStore: Expanding the Frontiers of Smartphone Ecosystems

Research paper thumbnail of Building complex Voice over IP (VoIP) applications based on open-source

The paper summarizes and proofs that existing VoIP programs are powerful and flexible enough to b... more The paper summarizes and proofs that existing VoIP programs are powerful and flexible enough to build complex applications. The applications are independent and can be used either stand-alone or within carrier-grade Telco environments. The described example of building a call center application (outbound calling) shows the power that lies not only in existing open-source Session Initiation Protocol (SIP) servers, but also in simple SIP tools. The costs for implementing those systems are at a very low level, as the functions each project performs are rather kept simple, but the combination possibilities are tremendously flexibility. The presented application has been deployed successfully within NGNlab as a Proof of Concept (PoC).

Research paper thumbnail of Hybrid IPTV Services with IMS Integration of IMS based IPTV with Broadcast and Unicast Mobile TV Services Using DVB-H

This paper presents a novel concept and prototype implementation of hybrid IPTV service based on ... more This paper presents a novel concept and prototype implementation of hybrid IPTV service based on IMS and DVB-H technologies. In the hybrid service, both traditional broadcast and unicast transmission technologies are used to deliver IPTV content. It is argued how such service scenario is effective and beneficial for hybrid use cases. The original technical contributions to ETSI technical report TR 182 030 about IMS-IPTV interconnection with DVB-H technology are presented in paper as well as description of our prototype implementation done within Celtic Netlab project.

Research paper thumbnail of Open-Source Based Prototype for Quality of Service (QoS) Monitoring and Quality of Experience (QoE) Estimation in Telecommunication Environments

This paper describes an implementation for monitoring the QoS and expecting the QoE of a voice co... more This paper describes an implementation for monitoring the QoS and expecting the QoE of a voice communication in a Real-time Transport Protocol (RTP) based telecommunication environment. The resulting QoS parameters are evaluated; the QoE is determined with the E-Model and processed for graphical presentation. With theuse of some open-source programming libraries, the presented prototype can be a helpful alternative for expensive measurement devices and is ready to be deployed in a widespread telecom environment at low cost.

Research paper thumbnail of Seamless WiFi-roaming in IMS network

Over recent years, the explosion of radio access technologies and wireless networking devices has... more Over recent years, the explosion of radio access technologies and wireless networking devices has triggered the intensive use of nomadic computing. Mobile devices receive intermittent network access, and alternate between connected and disconnected states. However, today's personal gadgets have more networking capabilities, wireless network coverage is becoming ubiquitous, and always-on IP-based services are now closer to reality. This paper shows a possible implementation of mobility in the IMS platform with using two wireless access points. A practical test was also done to investigate the quality of VoIP call as well as defects of this implementation.

Research paper thumbnail of IMS Interworking Using IBCF

This article focuses on the Interconnection Border Control Function (IBCF) entity in the current ... more This article focuses on the Interconnection Border Control Function (IBCF) entity in the current IP Multimedia Subsystem (IMS) architecture. Based on the analysis of various types of IMS interconnection scenarios, we describe our proof-of concept solution. We evaluate the signaling in several interconnected IMS domains using Open Sip Express Router (OpenSER) based prototype of IBCF.

Research paper thumbnail of Presence Management and Merging Presence Information for NGN Services

This paper describes an approach for interworking scenarios between Session Initiation Protocol (... more This paper describes an approach for interworking scenarios between Session Initiation Protocol (SIP) based and non SIP based frameworks (e.g. web services) in case of the presence management service. The characteristics of the concept of a centralized presence management will be introduced. Based on the Parlay X web service framework a presence management service solution has been developed, deployed and tested. The re-usability of the developed presence management service solution within an IP Television (IPTV) framework and the future potential of the presence service in various IPTV applications are analyzed.

Research paper thumbnail of Personalization of internet protocol television (IPTV) services in next-generation networks (NGN) architectures

This paper evaluates the existing NGN based IPTV architecture and services in the context of IPTV... more This paper evaluates the existing NGN based IPTV architecture and services in the context of IPTV service personalization within multi-user environment at home network and user equipment. Advanced scenarios of IPTV for providing fully personalized and interactive IPTV services using existing and new mechanisms in Converged NGN based IPTV architectures are proposed within this paper. The services can improve the quality of experience (QoE) and user expectation via new personalized IPTV service behavior.

Research paper thumbnail of The Potential of Consolidating SIP and XMPP Based Communication for Telecommunication Carriers

This paper describes an approach for combining Session Initiation Protocol (SIP) based voice comm... more This paper describes an approach for combining Session Initiation Protocol (SIP) based voice communication with Extensible Messaging and Presence Protocol (XMPP) based presence enhancements. The actual role of SIP and XMPP in the Internet Protocol (IP) based communication was analyzed, especially from the telecommunication carrier (Telco) point of view. The proposed infrastructure extends a typical SIP infrastructure with XMPP for presence status integration. XMPP will be used as instant messaging and presence (IM/P) service infrastructure, the presence information will be extended with SIP phone status information of telecommunication endpoints. A first prototype has been developed and tested successfully.

Research paper thumbnail of Voice over IP (VoIP) speech quality measurement with open-source software components

This paper proposes an alternative to expensive means for VoIP speech quality measurement. While ... more This paper proposes an alternative to expensive means for VoIP speech quality measurement. While current applications and measurement devices on the market are very expensive, the authors propose a solution based on open-source components that allows the determination of the Mean Opinion Score (MOS) value according the Perceptual Evaluation of Speech Quality (PESQ) test methodology.

Research paper thumbnail of Presence service integration using interconnected IP multimedia core networks (IM-CN)

This paper describes the integration of the presence management service into existing IP Multimed... more This paper describes the integration of the presence management service into existing IP Multimedia Subsystem (IMS) laboratory infrastructures. Both laboratories – NGNlab in Bratislava and the laboratory in Leipzig – use the Fraunhofer OpenIMS as core components for their testing IMS environment (i.e. Call Session Control Functions (CSCF), Home Subscriber Server (HSS)). The virtualization of these components will be described in this paper. Furthermore, the layer 3 interconnection and hence the possibility to share different applications between the locations will be discussed. The presence management service has been deployed in a state where it is ready to be used with current IMS clients, for both presence information sharing via the Session Initiation Protocol (SIP) and user authorization via Extended Markup Language (XML) Configuration Access Protocol (XCAP).

Research paper thumbnail of Combinational services of NGN based IPTV

This paper describes the general concept of combinational/blended services for IP-based Televisio... more This paper describes the general concept of combinational/blended services for IP-based Television (IPTV) services in next generation networks towards its service oriented architecture concept (SOA). Besides introducing general approaches of service reusability (SOA concepts), the service enables (e.g. presence, notification, messaging) as application service function in next generation networks will be outlined by standardization work in ETSI TISPAN and also explicit examples of prototypes are given. The extensibility will be elaborated within the IPTV subsystem and also as the possible interconnection with Web services. Selected cases have been successfully prototyped and deployed exemplary in the laboratory testbed.

Research paper thumbnail of Building complex Voice over IP (VoIP) applications based on open-source

2009 International Symposium Elmar, Sep 28, 2009

Research paper thumbnail of Voice over IP (VoIP) speech quality measurement with open-source software components

Proceedings Elmar 2010, Sep 15, 2010

Research paper thumbnail of Deliverable D3

Research paper thumbnail of Smart AppStore: Expanding the Frontiers of Smartphone Ecosystems

Research paper thumbnail of Building complex Voice over IP (VoIP) applications based on open-source

The paper summarizes and proofs that existing VoIP programs are powerful and flexible enough to b... more The paper summarizes and proofs that existing VoIP programs are powerful and flexible enough to build complex applications. The applications are independent and can be used either stand-alone or within carrier-grade Telco environments. The described example of building a call center application (outbound calling) shows the power that lies not only in existing open-source Session Initiation Protocol (SIP) servers, but also in simple SIP tools. The costs for implementing those systems are at a very low level, as the functions each project performs are rather kept simple, but the combination possibilities are tremendously flexibility. The presented application has been deployed successfully within NGNlab as a Proof of Concept (PoC).

Research paper thumbnail of Hybrid IPTV Services with IMS Integration of IMS based IPTV with Broadcast and Unicast Mobile TV Services Using DVB-H

This paper presents a novel concept and prototype implementation of hybrid IPTV service based on ... more This paper presents a novel concept and prototype implementation of hybrid IPTV service based on IMS and DVB-H technologies. In the hybrid service, both traditional broadcast and unicast transmission technologies are used to deliver IPTV content. It is argued how such service scenario is effective and beneficial for hybrid use cases. The original technical contributions to ETSI technical report TR 182 030 about IMS-IPTV interconnection with DVB-H technology are presented in paper as well as description of our prototype implementation done within Celtic Netlab project.

Research paper thumbnail of Open-Source Based Prototype for Quality of Service (QoS) Monitoring and Quality of Experience (QoE) Estimation in Telecommunication Environments

This paper describes an implementation for monitoring the QoS and expecting the QoE of a voice co... more This paper describes an implementation for monitoring the QoS and expecting the QoE of a voice communication in a Real-time Transport Protocol (RTP) based telecommunication environment. The resulting QoS parameters are evaluated; the QoE is determined with the E-Model and processed for graphical presentation. With theuse of some open-source programming libraries, the presented prototype can be a helpful alternative for expensive measurement devices and is ready to be deployed in a widespread telecom environment at low cost.

Research paper thumbnail of Seamless WiFi-roaming in IMS network

Over recent years, the explosion of radio access technologies and wireless networking devices has... more Over recent years, the explosion of radio access technologies and wireless networking devices has triggered the intensive use of nomadic computing. Mobile devices receive intermittent network access, and alternate between connected and disconnected states. However, today's personal gadgets have more networking capabilities, wireless network coverage is becoming ubiquitous, and always-on IP-based services are now closer to reality. This paper shows a possible implementation of mobility in the IMS platform with using two wireless access points. A practical test was also done to investigate the quality of VoIP call as well as defects of this implementation.

Research paper thumbnail of IMS Interworking Using IBCF

This article focuses on the Interconnection Border Control Function (IBCF) entity in the current ... more This article focuses on the Interconnection Border Control Function (IBCF) entity in the current IP Multimedia Subsystem (IMS) architecture. Based on the analysis of various types of IMS interconnection scenarios, we describe our proof-of concept solution. We evaluate the signaling in several interconnected IMS domains using Open Sip Express Router (OpenSER) based prototype of IBCF.

Research paper thumbnail of Presence Management and Merging Presence Information for NGN Services

This paper describes an approach for interworking scenarios between Session Initiation Protocol (... more This paper describes an approach for interworking scenarios between Session Initiation Protocol (SIP) based and non SIP based frameworks (e.g. web services) in case of the presence management service. The characteristics of the concept of a centralized presence management will be introduced. Based on the Parlay X web service framework a presence management service solution has been developed, deployed and tested. The re-usability of the developed presence management service solution within an IP Television (IPTV) framework and the future potential of the presence service in various IPTV applications are analyzed.

Research paper thumbnail of Personalization of internet protocol television (IPTV) services in next-generation networks (NGN) architectures

This paper evaluates the existing NGN based IPTV architecture and services in the context of IPTV... more This paper evaluates the existing NGN based IPTV architecture and services in the context of IPTV service personalization within multi-user environment at home network and user equipment. Advanced scenarios of IPTV for providing fully personalized and interactive IPTV services using existing and new mechanisms in Converged NGN based IPTV architectures are proposed within this paper. The services can improve the quality of experience (QoE) and user expectation via new personalized IPTV service behavior.

Research paper thumbnail of The Potential of Consolidating SIP and XMPP Based Communication for Telecommunication Carriers

This paper describes an approach for combining Session Initiation Protocol (SIP) based voice comm... more This paper describes an approach for combining Session Initiation Protocol (SIP) based voice communication with Extensible Messaging and Presence Protocol (XMPP) based presence enhancements. The actual role of SIP and XMPP in the Internet Protocol (IP) based communication was analyzed, especially from the telecommunication carrier (Telco) point of view. The proposed infrastructure extends a typical SIP infrastructure with XMPP for presence status integration. XMPP will be used as instant messaging and presence (IM/P) service infrastructure, the presence information will be extended with SIP phone status information of telecommunication endpoints. A first prototype has been developed and tested successfully.

Research paper thumbnail of Voice over IP (VoIP) speech quality measurement with open-source software components

This paper proposes an alternative to expensive means for VoIP speech quality measurement. While ... more This paper proposes an alternative to expensive means for VoIP speech quality measurement. While current applications and measurement devices on the market are very expensive, the authors propose a solution based on open-source components that allows the determination of the Mean Opinion Score (MOS) value according the Perceptual Evaluation of Speech Quality (PESQ) test methodology.

Research paper thumbnail of Presence service integration using interconnected IP multimedia core networks (IM-CN)

This paper describes the integration of the presence management service into existing IP Multimed... more This paper describes the integration of the presence management service into existing IP Multimedia Subsystem (IMS) laboratory infrastructures. Both laboratories – NGNlab in Bratislava and the laboratory in Leipzig – use the Fraunhofer OpenIMS as core components for their testing IMS environment (i.e. Call Session Control Functions (CSCF), Home Subscriber Server (HSS)). The virtualization of these components will be described in this paper. Furthermore, the layer 3 interconnection and hence the possibility to share different applications between the locations will be discussed. The presence management service has been deployed in a state where it is ready to be used with current IMS clients, for both presence information sharing via the Session Initiation Protocol (SIP) and user authorization via Extended Markup Language (XML) Configuration Access Protocol (XCAP).

Research paper thumbnail of Combinational services of NGN based IPTV

This paper describes the general concept of combinational/blended services for IP-based Televisio... more This paper describes the general concept of combinational/blended services for IP-based Television (IPTV) services in next generation networks towards its service oriented architecture concept (SOA). Besides introducing general approaches of service reusability (SOA concepts), the service enables (e.g. presence, notification, messaging) as application service function in next generation networks will be outlined by standardization work in ETSI TISPAN and also explicit examples of prototypes are given. The extensibility will be elaborated within the IPTV subsystem and also as the possible interconnection with Web services. Selected cases have been successfully prototyped and deployed exemplary in the laboratory testbed.