WO2013072193A2 - Method and apparatus for allocating a transfer function - Google Patents

Method and apparatus for allocating a transfer function Download PDF

Info

Publication number
WO2013072193A2
WO2013072193A2 PCT/EP2012/071557 EP2012071557W WO2013072193A2 WO 2013072193 A2 WO2013072193 A2 WO 2013072193A2 EP 2012071557 W EP2012071557 W EP 2012071557W WO 2013072193 A2 WO2013072193 A2 WO 2013072193A2
Authority
WO
WIPO (PCT)
Prior art keywords
indication
user
packet data
network interface
data network
Prior art date
Application number
PCT/EP2012/071557
Other languages
French (fr)
Other versions
WO2013072193A3 (en
Inventor
Miikka Juhana POIKSELKÄ
Jari Mutikainen
Original Assignee
Nokia Siemens Networks Oy
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nokia Siemens Networks Oy filed Critical Nokia Siemens Networks Oy
Publication of WO2013072193A2 publication Critical patent/WO2013072193A2/en
Publication of WO2013072193A3 publication Critical patent/WO2013072193A3/en

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
    • H04L65/10—Architectures or entities
    • H04L65/1016—IP multimedia subsystem [IMS]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
    • H04L65/1066—Session management
    • H04L65/1073—Registration or de-registration
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
    • H04L65/1066—Session management
    • H04L65/1083—In-session procedures
    • H04L65/1094—Inter-user-equipment sessions transfer or sharing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
    • H04L65/1066—Session management
    • H04L65/1083—In-session procedures
    • H04L65/1095—Inter-network session transfer or sharing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0011—Control or signalling for completing the hand-off for data sessions of end-to-end connection
    • H04W36/0022—Control or signalling for completing the hand-off for data sessions of end-to-end connection for transferring data sessions between adjacent core network technologies
    • H04W36/00224—Control or signalling for completing the hand-off for data sessions of end-to-end connection for transferring data sessions between adjacent core network technologies between packet switched [PS] and circuit switched [CS] network technologies, e.g. circuit switched fallback [CSFB]
    • H04W36/00226—Control or signalling for completing the hand-off for data sessions of end-to-end connection for transferring data sessions between adjacent core network technologies between packet switched [PS] and circuit switched [CS] network technologies, e.g. circuit switched fallback [CSFB] wherein the core network technologies comprise IP multimedia system [IMS], e.g. single radio voice call continuity [SRVCC]

Definitions

  • the present invention relates to a mechanism for allo ⁇ cating a transfer function .
  • the present invention is related to a method and apparatus for allocating an access transfer function based on a packet data network interface or a communication service .
  • Session Initiation Protocol defined by Internet Engineering Task Force (IETF) is used for con ⁇ trolling communication .
  • SIP Internet Protocol
  • IMS Internet Protocol Multimedia Subsystem
  • 3GPP 3rd Generation Partnership Project
  • SIP Session Initiation Protocol
  • IETF Internet Engineering Task Force
  • SIP is an application-layer control protocol for creating, modifying, and terminating sessions with one or more participants .
  • These ses- sions may include Internet multimedia conferences , In ⁇ ternet telephone calls, and multimedia distribution .
  • Members in a session can communicate via multicast or via a mesh of unicast relations , or a combination of these .
  • Session Description Protocol SDP is a protocol which conveys information about media streams in mu11i- media sessions to allow the recipients of a session description to participate in the session .
  • Diameter protocol has been defined by IETF and is intended to provide an Authentication, Authorization and Accounting (AAA) framework for applications such as network access or IP mobility .
  • AAA Authentication, Authorization and Accounting
  • network elements such as a user equipment and another communication equipment or user equipment, a database, a server, etc .
  • one or more intermediate network elements such as control network elements , support nodes , service nodes and interworking elements are involved which may belong to different communication networks .
  • VoIP voice over IP
  • CS circuit switched
  • VoIP applications can support handing over an active VoIP session to a circuit switched (CS) network, whereas some VoIP applications do not support interworking with the CS network .
  • UE User Equipment
  • UE can support the use of more than one VoIP applications simultaneously and the UE and the network must have common understanding on handover capability of an active session, and especially, when the UE has several active session parallel .
  • Service continuity describes ATCF allocation proce ⁇ dure and one of the ATCF allocation principles defines that in case of multiple registrations from the UE from multiple access networks, an SCC AS shall only receive and use one STN-SR, from an ATCF in the mobile network .
  • Embodiments of the present invention can overcome some of above drawbacks by providing an apparatus , a method and a computer program product comprising obtaining an indication of a packet data network interface for a us ⁇ er, and, allocating an access transfer control function for the user, wherein the allocating comprises to allocate the access transfer control function for the user if the indication of the packet data network interface indicates internet protocol multimedia subsystem (IMS) .
  • the allocating can comprise not to allocate the access transfer control function for the user if the indication of the packet data network interface does not indicate internet protocol multimedia subsystem (IMS) .
  • the indication of the packet data network interface can comprise an access point name (APN) .
  • the obtaining the indication can comprises one of :
  • PCRF policy and/or charging entity
  • the access transfer control function can comprise an en- tity being capable of :
  • STN-SR session transfer number - single .radio
  • an apparatus comprising receiving an indication of a communication service associated with a user, and, allocating an access transfer control function for the user, wherein the allocating comprises to allocate the access transfer control function for the user if the indication of the communication service indicates a conversational voice service .
  • the allocating can comprise not to allocate the access transfer control function for the user if the indication of the packet data network interface does not indicate a conversational voice service .
  • the indication of the communication service can comprise at least one of :
  • IARI IMS Application Reference Identifier
  • the receiving the indication can comprise receiving in a session initiation protocol request from the user (SIP INVITE, SIP REGISTER) .
  • an apparatus comprising obtaining an indication of a packet data network interface for a user, and, de ⁇ ciding if an access transfer control function is to be allocated for the user, wherein the deciding comprises allocating the access transfer control function for the user if the indication of the packet data network interface indicates internet protocol multimedia subsystem (IMS) .
  • the deciding can comprise not to allocate the access transfer control function for the user if the indication of the packet data network interface does not indicate internet protocol multimedia subsystem (IMS) .
  • an apparatus comprising receiving an indication of a communication service associated with a user, and, deciding if an access transfer control function is to be allocated for the user, wherein the deciding comprises allocating the transfer control function for the user if the indication of the communication service indicates a conversational voice service .
  • the deciding can comprises not to allocate the access transfer control function for the user if the indication of the communication service does not indicate a conversational voice service .
  • Figure 1 illustrates architecture and interfaces between relevant network elements according to aspects of the invention .
  • Figure 2 illustrates examples of internal structure and functions of apparatuses implementing aspects of the invention .
  • FIGS 3 and 4 illustrate processes according to aspects of the invention .
  • Figure 5 shows signaling according to aspects of the in ⁇ vention .
  • Figure 6 illustrate architecture and interfaces between relevant network elements according to aspects of the invention .
  • Figure 7 illustrates identification of IMS applications relevant for aspects of the inventions .
  • FIGS 8 and 9 illustrate processes according to aspects of the invention .
  • Call Session Control Functions implement a session control function in SIP layer.
  • the CSCF can act as Proxy CSCF (P-CSCF) , Serving CSCF (S-CSCF) or Interrogating CSCF (I-CSCF) .
  • P-CSCF Proxy CSCF
  • S-CSCF Serving CSCF
  • I-CSCF Interrogating CSCF
  • the P-CSCF is the first contact point for the User Equipment (UE) within the IMS ;
  • the S-CSCF handles the session states in the network;
  • the I-CSCF is mainly the contact point within an operator ' s network for all IMS connections destined to a subscriber of that network operator, or a roaming subscriber currently located within that network operator ' s service area.
  • the functions performed by the I-CSCF are, for example, assigning an S-CSCF to a user performing a SIP registration and routing SIP requests received from another network towards the S-CSCF .
  • the S-CSCF can perform the session control services for the UE . It maintains a session state as needed by the network operator for support of the services and ma be acting as Registrar, i.e. it accepts registration requests and makes its information available through the location server (e.g. HSS) .
  • the S- CSCF is the central point to users that are hosted by this S-CSCF .
  • the S-CSCF can provide services to registered and unregistered users when it is assigned to these users . This assignment can be stored in the Home Sub ⁇ scriber Server (HSS ) .
  • HSS Home Sub ⁇ scriber Server
  • UE user equipment
  • S-CSCF serving CSCF
  • Universal mobile telecommunications system (UMTS) ter ⁇ restrial radio access network is radio access network (RAN) which consists of radio network controllers (RNC) and base transceiver stations (BTS) and which is located between the Iu interface and the wideband code division multiple access ( CDMA) radio interface .
  • RNC radio network controllers
  • BTS base transceiver stations
  • Serving GPRS support node is a general packet ra- dio service (GPRS) support node that serves GPRS mobile stations by sending or receiving packets via a base station subsystem or a radio access network .
  • the SGSN is the basic element of the GPRS infrastructure . It can store for each mobile in its context different parame- ters used to route the packets, for example information about the mobile ' s location .
  • IP connectivity access network is set of network entities and interfaces that can provide connectiv ity for IP transport between UE and the IMS .
  • a GPRS network can be used as an IP-CAN .
  • High-speed packet access is a set of mobile tele phone communication protocols for the radio interface with high data rates .
  • LTE and E-UTRAN are an evolution effort within the 3GPP to improve the UMTS standard to cope with future requirements , providing a high-data-rate , low-latency, and packet-optimised radio-access network .
  • a packet data network gateway ( P-G , PDN gateway, PDN GW) is a gateway that can provide a permanent IP-based point of attachment for access via the evolved UTRAN .
  • Evolved node B is a base transceiver station that controls all radio-related functions in the radio access part of the evolved UTRAN (E-UTRAN) .
  • Multimedia telephony service (MMTel) is 3GPP specified enhanced telephone service that is based on the IMS and that provides network operators with the tools to build converged fixed and mobile voice over IP services with multimedia support .
  • the MMtel service can use the media capabilities such as voice ; real-time video ; text ; file transfer; and sharing of pictures , audio , and video clips .
  • the number of supplementary services has been specified for the multimedia telephony service .
  • IMS communication service identifier is a fea ⁇ ture-tag that indicates that a UE supports the MMtel.
  • the UE itself is not aware of the ICSI of a session be cause a P-CSCF removes the P-Asserted-Service header from SIP signaling towards the UE .
  • IMS service continuity provides the capability of continuing ongoing communication sessions with multiple media across different access networks or across different UEs under the control of the same subscriber .
  • a service centralization and continuity application server (SCC-AS) is an AS responsible for service continuity in ⁇ cluding single radio voice call continuity (SR VCC) , which is a handover between a packet-switched ( PS ) access and a circuit-switched (CS) access .
  • SR VCC single radio voice call continuity
  • QCI Quality of service class indicator
  • QCI Quality of service class indicator
  • the QCI can refer, for example, to scheduling weights , admission thresholds , queue management thresholds, and link layer protocol configurations.
  • a subset of QoS class indicators is typically standardised to support global roaming. For conversational voice solutions, e.g. MMtel, QCI is set to value 1.
  • Access point name is a logical name that describes the actual connected access point (AP) to the external packet data network according to domain name system naming conventions .
  • the APN is composed of a mandatory net- work identifier and an optional operator identifier .
  • APN is a reference to the gateway GPRS support node (GGSN) to be used.
  • GGSN gateway GPRS support node
  • Access point (AP) refers to a physical device that can connect wired and wireless network parts together .
  • the APN indicates a packet data network interface for user traffic .
  • VoLTE Voice over LTE VoLTE, as defined by GSM Association (GSMA) , describes a protocol profile for IMS/SIP based voice over LTE service .
  • VoLTE SIP protocol is based on
  • APN An IMS specific APN is used for VoLTE which means that a "well- known" APN has been defined for the IMS .
  • This APN name is "IMS”, which is also the APN Network Identifier part of the full APN .
  • the APN Operator Identifier part of the full APN depends on the public land mobile network ( PLMN) whose packet gateway ( PGW) the UE is anchored to .
  • PLMN public land mobile network
  • PGW packet gateway
  • the "well-known" IMS APN can be provisioned as the de- fault APN for the IMS subscriber, meaning that there is no need to configure it to the device or the serving network .
  • IMS APN ensures the voice sessions are provided in local breakout (LBO) ) manner, i.e. the IP address is allocated from the serving network, and voice media can be routed directly between the serving networks , without routing it to the home network at first .
  • LBO local breakout
  • EPS evolved packet system
  • the voice media uses the QCI value 1 bearer, which is a guaranteed bit rate (GBR) bearer . This ensures a certain QoS for voice media, and also single radio voice call continuity (SRVCC) can be offered.
  • GRR guaranteed bit rate
  • Rich Communication Suite is another GSMA SIP/IMS service profile, but for Presence, Instant Message (IM) chatting, video sharing, image sharing, etc non-real time type of communication .
  • RCS can support also the VoLTE in addition to the previously listed non-real time media types .
  • the RCS can be combined in two ways with the VoLTE application; 1 ) RCS + VoLTE client is integrated with the mobile handheld device,
  • RCS + VoLTE is offered separate to the mobile cellular modem hardware, "splitted client” .
  • An example of the latter is e.g. when RCS+VoLTE runs in PC laptop, and LTE radio is offered as universal serial bus (USB) modem .
  • USB universal serial bus
  • the RCS+VoLTE client uses the IMS APN and in the latter sce ⁇ nario it uses any APN which provides the Internet connectivity, e.g. "Internet” .
  • An Access Transfer Control Function is a function in a serving network (in a visited network if a user is roaming) .
  • An ATCF can be included in the session path for the duration of a session before and after an access transfer .
  • the ATCF can be co-located, for example, with the P-CSCF .
  • Functions of the ATCF can include :
  • the SCC AS which anchors the IMS sessions for SRVCC determines whether the session is a candidate for SRVCC or not .
  • the QCI value is used in EPS bearer level, the enodeB can determine the QCI value when it makes a deci ⁇ sion on whether to initiate SRVCC or not .
  • the media description negotiated in session description protocol (SDP) offer/answer (contains audio media with bi-directional speech codec, e.g. adaptive multi-rate (AMR) speech codec) , and/or the IMS service identifier ( ICSI ) (e.g.
  • the SDP details and the IMS service identifiers are identical for these two kinds of sessions, thereby the SCC-AS has no means to differentiate between the two services.
  • the SCC AS must anchor both kinds of sessions (because it is not able to distinguish them) , but this is only a minor performance issue, if any . More serious issue may occur when the user is able to estab ⁇ lish both kinds of sessions simultaneously . In this case, it may be the UE understands that RCS-VoLTE sessions it has initiated are not applicable for SRVCC, but the SCC AS does not have this information . This means when the SRVCC event takes place, i.e. the UE is moving from LTE coverage to UTRAN/GERAN, the SCC AS may make a wrong decision on which IMS session must be transferred to the CS domain .
  • a practical situation where this sce ⁇ nario happens may be when the LTE mobile device is used in a WiFi (wireless local area network (WLAN) tethering mode, it may establish VoLTE voice sessions at the same time when some of the tethered PC s establishes RCS-
  • WiFi wireless local area network
  • VoLTE voice sessions both under the same IMS user account .
  • APN packet data network interface
  • the SCC-AS can store the APN per a session and/or user and determine based on the used APN which of sessions are applicable for SRVCC (for example, only "IMS APN" is applicable for SRVCC) .
  • the UE can know the APN and the QCI value as per current procedures. Thereby, according to an aspect of the invention, when both the UE and the network (SCC AS) apply the same handover criteria, i.e. the APN name and/or QCI value to determine the applicability for the SRVCC, there is no issue of wrong decision .
  • the P-CSCF can obtain the APN from a policy and charging control function (PCRF) , for example, in a Diameter signalling message (Rx interface) .
  • PCRF policy and charging control function
  • the P-CSCF can inspect an IP address of the UE .
  • IMS APN can be used for voice communication. This implies that a dedicated range of IP addresses can be used in the IMS APN and the UE obtains its IP address within that dedicated range during establishment of the packet data network (PDN) connec- tions .
  • the IP address range (per APN) information can be configured in the P-CSCF and thereby the P-CSCF can be able to detect that the IP address of the UE belongs to the specific range, for example, to the range that is used by the IMS APN.
  • a P-CSCF can become aware of an APN during a registration procedure of UE, for example, when the UE initiates IMS registration .
  • the P-CSCF can transmit the APN information fur- ther to a SCC AS, via an S-CSCF, e.g. as part of a SIP
  • a possible implementation is to re-use the solution which has been defined for enhanced-SRVCC in 3GPP Rel 10, where an access transfer control function (ATCF) can allocate a session transfer number for SRVCC (STN-SR) and a SIP REGISTER can be used to carry it to a S-CSCF, which in turn can then generate a reg-event notification to a SCC-AS , carrying the STN-SR.
  • ATCF access transfer control function
  • STN-SR session transfer number for SRVCC
  • SIP REGISTER can be used to carry it to a S-CSCF, which in turn can then generate a reg-event notification to a SCC-AS , carrying the STN-SR.
  • the APN name can be carried in the similar manner from the P-CSCF via the S-CSCF to the SCC-AS , except that APN name can be determined and can be put into a SIP REGISTER by the P-CSCF.
  • the SCC-AS can use the APN name to
  • the P-CSCF can add its own address in a SIP REGISTER request within a PATH header .
  • the APN information may be included in the PATH header, for example, as a value of a new Uniform Resource Identifier (URI) parameter de fined for that purpose .
  • the new URI parameter can be, for example, "g .3gpp . apn" and it can take, for example, value of "IMS", "Internet", or
  • CSCF can be:
  • Path : si : cscf1. isitedl . it ; Ir ; g .3gp . apn IMS where "g .3gpp . apn" is a new URI parameter and "IMS" is the value of the parameter containing the APN infor ⁇ mation .
  • the S-CSCF can deliver the APN information further to an SCC AS using existing capabilities .
  • a P-CSCF can include an APN in a SIP INVITE request instead of, or in addition to, including the APN in a SIP REGISTER request.
  • the SCC-AS can receive the APN in a SIP INVITE request .
  • Figure 1 shows network elements and interfaces relevant for some aspects of the invention, when UE 1 , for example, a mobile handset, communicates with a mobile core network over radio access network 2 , for example, over LTE 2 access (radio network specific components are not shown in the figure) .
  • UE 1 for example, a mobile handset
  • radio access network 2 for example, over LTE 2 access
  • Bottom part of figure 1 shows the data transmission path where data packets to/ from the UE 1 traverse a packet data gateway 3 (PGW) .
  • PGW 3 packet data gateway 3
  • One or more APNs can be defined at the PGW 3 for various packet data services , for example, an IMS APN which can support voLTE .
  • Each APN is associated with certain transmission path characteristics , e.g. QoS parameters .
  • the IMS APN can support QoS required for conversational voice services .
  • the radio access network 2 can be a HSPA access 2 or WCDMA 2 access , in which case the packet data gateway 3 can be a GGSN 3.
  • a ⁇ - CSCF 4 is the first signaling (SIP) contact point for the UE 1 in the IMS network .
  • the P-CSCF 4 can interface the PGW 3 via a policy and charging control function (PCRF) 5 and can thereby become aware of the APN in the transmission path (e.g. IMS APN) , for example during IMS registration of the UE 1.
  • the P-CSCF 4 communicates with an S-CSCF 6 which is assigned for the UE 1 during the IMS registration .
  • a SCC-AS 7 can be involved in SIP sig ⁇ naling path path, when service continuity is required, for example, handover of a voice call from the IMS to a CS network (e.g. SRVCC) can take place .
  • a CS network e.g. SRVCC
  • an APN can be used to select a SIP registration when receiving a request to route a terminating session to a user .
  • T-ADS functionality can be part of an SCC-AS 7, and the SCC-AS 7 can learn the APN as described above .
  • the T-ADS can store the binding between the registration details (e.g. Contact IP address and globally routable user agent (UA) uniform resource iden ⁇ tifier (GRUU) ) and the APN .
  • a user1 can first register to the network with REGISTER request 51.
  • the same userl can then register for the second time with REGISTER 52 , this time from another terminal device identified with GRUU2 and using another APN, namely IMS APN.
  • the SCC-AS 7 can store identity, GRUU and APN information from the
  • the T-ADS / SCC-AS 7 can indicate the selection to an S-CSCF 6 in INVITE request 55 towards the userl .
  • the GRUU is used and is different between the registrations, e.g. when the registrations 51 and 52 were initiated from different devices as in Fig 5 example, the GRUU can be used from the T-ADS / SCC-AS 7 to force the S-CSCF 6 to select a certain registration .
  • the GRUU can be used from the T-ADS / SCC-AS 7 to force the S-CSCF 6 to select a certain registration .
  • INVITE 55 with GRUU2 can be sent to S-CSCF 6 which forces the S-CSCF 6 to select the registration using the IMS APN, thereby enabling SRVCC .
  • GRUU is the same for more than one registration which use different APNs (e.g. VoLTE and RCS client reside in the same mobile device )
  • a new indicator can be implemented in IMS service control interface (ISC) interface, or the reg-id (Outbound, IETF RFC 5626) can be used as a fea- ture tag in the ISC interface.
  • a new media feature tag can be defined for this purpose.
  • FIG. 2 illustrates examples of internal structure and functions of apparatus implementing aspects of the invention .
  • the apparatus which can be a session control entity, for example, a P-CSCF 4 or a SCC-AS 7 can have a receiving unit 21 ( receiver) configured to receive sig ⁇ naling messages from UE 1 or from other network entities
  • the apparatus can have a transmitting unit 22
  • the transmitting unit 22 can include an indication of an APN which the UE 1 is using in the request to be transmitted, for example, in SIP REGISTER request sent by the P- CSCF 4 to an S-CSCF 6.
  • a processing unit 23 can be configured to handle information received in signalling messages and to make session control decisions, for example, de- termining if a certain session (or session leg) is / will be applicable to a handover (e.g. SRVCC) .
  • the processing unit 23 can make determinations and/or decisions based on the APN or QCI used for accessing services , and can perform a APN to quality class indictor (QCI ) map- ping .
  • QCI quality class indictor
  • the processing unit 23 can be configured to determine an APN based on comparing an IP address of the UE 1 to dedicated ranges of IP addresses reserved for APNs .
  • the IMS APN can have a dedicated IP address range configured at a memory unit 24 (memory) of the apparatus .
  • the memory unit 24 can be configured to store registration related information, for example, binding between the registration details (e.g. Contact IP, GRUU) and an indication of an APN for each registration .
  • registration details e.g. Contact IP, GRUU
  • an indication of an APN for each registration e.g. Contact IP, GRUU
  • a QCI or a specific indication indicating whether SRVCC is possible can be stored, based on the AP .
  • a session control entity may be physically implemented in a switch, router, server or other hardware platform or electronic equipment which can support data transmission and processing tasks , or can be implemented as a component of other existing device .
  • FIGS 3 and 4 show example processes implementing aspects of the invention .
  • a further aspect of the invention relates to 3GPP SR-VCC and allocation and/or selection of an Access Transfer Control Function (ATCF) to improve performance of SRVCC.
  • ATCF Access Transfer Control Function
  • VoIP Voice over LTE
  • VoIP Voice over HSPA
  • APN name is pre-defined so that there is no need to configure it to the device or the serving network .
  • Service continuity (SC) describes ATCF allocation procedure and one of the ATCF allocation principles defines that in case of multiple registrations from the UE from multi le access networks , an SCC AS shall only receive and use one STN-SR, from an ATCF in the mobile network .
  • the existing Release 11 stage-3 solution assumes that the UE is served by the same ATCF in all the registration flows in the mobile network (E-UTRAN, UTRAN, GERAN, CDMA2000) . If the registrations from the UE are for different ac ⁇ Waits, e.g. a 3GPP mobile access, and WL N, then a so ⁇ lution can be built upon on the access type, e.g. only if the ATCF is serving a 3GPP mobile access , the ATCF informs its address to the SCC AS. However, this can not work when multiple registrations are for 3GPP mobile access .
  • a UE 1 may have more than one independent SIP/IMS stack which may perform IMS registration independentl .
  • SIP/IMS stack SIP Stack 1
  • RCS Rich Communication Suite
  • IMS registrations can take place and more than one ATCF 8a, 8b and consequently more than one STN-SR can be allocated for the single UE 1.
  • ATCF 81, 8b allocation process by a P-CSCF 4a, 4b can currently be based on local policy/implementation specific.
  • the SIP/IMS stacks can discover the P-CSCF 4a, 4b addresses independently, therefore it can be expected that each registration can use a different P-CSCF 4a, 4b address and communicates with different P-CSCFs 4a, 4b.
  • This means any of the selected P-CSCFs 4a, 4b is not able to coordinate and/or ensure that only a single ATCF 8a, 8b is used . Therefore it is likely that each regis ⁇ tration gets a separate ATCF 8a, 8b allocated.
  • two different PGWs 3 and PCRFs 5 are involved (not shown in Fig 6 ) .
  • an SCC AS 7 can detect that two different ATCF 8a, 8b / STN-SRs are provided to the user and the SCC AS 7 can take action to disable ATCF functionality completely . Disabling the ATCF f nctionality completely can be considered real drawback, since the eSRVCC cannot be provided at all to the UE 1. It has also been suggested that both the SCC AS 7 and the UE 1 can maintain record of the allocated ATCF 8a, 8b and these entities can thereby ensure that new sessions will use the same ATCF functionality. This solution, however, impacts both UE 1 implementation and the network and thereby it does not work with legacy devices .
  • a P-CSCF 4a, 4b can inspect a used APN which is used to register UE 1 to the IMS network to decide whether to allocate an ATCF 8a, 8b or not. If the APN is IMS APN then the P-CSCF 4a, 4b can allocate an ATCF 8a, 8b. If the APN is not IMS APN then the P-CSCF 4a, 4b does not allocate an ATCF.
  • the processing unit 23 (processor, CP) of Fig 2 can be configured to examine the APN and to decide if an ATCF 8a, 8b is to be allocated or not .
  • the P-CSCF 4a, 4b can learn the used APN as explained earlier when describing other aspects of the invention .
  • the solution works for multiple registrations via 3GPP mobile access, when only one of the registrations is performed via the IMS AP .
  • a P-CSCF 4a, 4b can inspect the used IMS communication service identifier ( ICSI ) and/or IMS Application Reference Identifier ( IARI ) to decide whether to allocate ATCF 8a, 8b or not .
  • IARI value can identify the application to be invoked.
  • I f the ICSI and/or IARI can identif carrier grade operator voice service, such as VoLTE, then the P-CSCF 4a, 4b can allocate an ATCF 8a, 8b, otherwise it does not allocate the ATCF .
  • the decision can be made based on the value of either ICSI or IARI alone, or, based on the combination of values of both ICSI and IARI .
  • ICSI and/or IARI can be received by a P-CSCF 4 in a SIP request, for example, in REGISTER or INVITE request .
  • Figure 7 shows an example of identification of applications using communication service identifier (e.g. ICSI ) and applica ⁇ tion reference (e.g. IARI ) .
  • communication service identifier e.g. ICSI
  • applica ⁇ tion reference e.g. IARI
  • carrier grade operator voice service a conversational voice service is meant, in other words , it is the prima ⁇ ry voice service of the operator, offering the QoS and service level which is comparable to CS voice (like MMTE1) .
  • the P-CSCF 4a, 4b does not allocate a ATCF, otherwise it can allocate a ATCF 8a, 8b.
  • the processing unit 23 (processor, CP) of Fig 2 can be configured to inspect received ICSI and/or IARI and to decide if an ATCF 8a, 8b is to be allocated.
  • This aspect is beneficial if separate IMS/SIP stacks ex ist and both stacks (VoLTE and other IMS services) can use the IMS APN and/or more than one carrier grade voice services need to be offered via IMS APN, and also if e - siliency mechanism needs to be offered to VoLTE, where the VoLTE application registers multiple times via IMS APN, but with different P-CSCF 4a, 4b.
  • an access technology via which signaling is transferred to and from a network element or node may be any technology by means of which a node can access an access network (e.g. via a base station or generally an access node) .
  • WiMAX Worldwide Interoperability for Microwave Access
  • BlueTooth Infra ⁇ red, and the like
  • access technology in the sense of the present invention implies also wirebound technologies, e.g. IP based access technologies like cable networks or fixed lines but also circuit switched access technologies ; access technologies may be distin- guishable in at least two categories or access domains such as packet switched and circuit switched, but the existence of more than two access domains does not impede the invention being applied thereto,
  • - usable access networks may be any device, apparatus, unit or means by which a station, entity or other user equipment may connect to and/or utilize services offered by the access network; such services include, among oth ⁇ er s, data and/or (audio-) visual communication, data download etc . ;
  • a user equipment may be any device, apparatus , unit or means by which a system user or subscriber may experience services from an access network, such as a mobile phone, personal digital assistant PDA, or computer;
  • any method step is suitable to be imple- mented as software or by hardware without changing the idea of the invention in terms of the functionality implemented;
  • CMOS Complementary MOS
  • BiMOS Bipolar MOS
  • BiCMOS Bipolar CMOS
  • ECL emitter Coupled Logic
  • TTL Transistor-Transistor Logic
  • any method steps and/or devices , units or means likely to be implemented as software components may for example be based on any security architecture capable e.g. of authentication, authorization, keying and/or traffic protection;
  • - devices , apparatuses , units or means can be imple ⁇ mented as individual devices , apparatuses , units or means, but this does not exclude that they are imple- mented in a distributed fashion throughout the system, as long as the functionality of the device, apparatus , unit or means is preserved,
  • an apparatus may be represented by a semiconductor chip, a chipset, or a (hardware) module comprising such chip or chipset ; this , however, does not exclude the possibility that a functionality of an apparatus or module, instead of being hardware implemented, be implemented as software in a (software) module such as a com ⁇ puter program or a computer program product comprising executable software code portions for execution/being run on a processor;
  • - a device may be regarded as an apparatus or as an as ⁇ sembly of more than one apparatus , whether functionally in cooperation with each other or functionally inde- pendently of each other but in a same device housing, for example .
  • the invention is not limited to session handling in the IMS network (s) , but may also be applied in other type of networks having similar kind of support for handing over a session to another access technology depending on a service type and/or characteristic of the transmission path (e.g. QoS requirements) .
  • Functions of the session control entity described above may be implemented by code means, as software, and loaded into memory of a computer .

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Business, Economics & Management (AREA)
  • General Business, Economics & Management (AREA)
  • Data Exchanges In Wide-Area Networks (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

The invention relates to a session control entity, methods and computer programs for obtaining an indication of a packet data network interface for a user, and, allocating an access transfer control function for the user, wherein the allocating comprises to allocate the access transfer control function for the user if the indication of the packet data network interface indicates internet protocol multimedia subsystem (IMS).

Description

Description
Title
Method and apparatus for allocating a transfer function
Technical field of the invention: The present invention relates to a mechanism for allo¬ cating a transfer function . In particular, the present invention is related to a method and apparatus for allocating an access transfer function based on a packet data network interface or a communication service .
Background of the invention :
Within the IP (Internet Protocol) Multimedia Subsystem (IMS) as defined by 3rd Generation Partnership Project ( 3GPP) Session Initiation Protocol (SIP) defined by Internet Engineering Task Force ( IETF) is used for con¬ trolling communication . SIP is an application-layer control protocol for creating, modifying, and terminating sessions with one or more participants . These ses- sions may include Internet multimedia conferences , In¬ ternet telephone calls, and multimedia distribution . Members in a session can communicate via multicast or via a mesh of unicast relations , or a combination of these . Session Description Protocol (SDP) is a protocol which conveys information about media streams in mu11i- media sessions to allow the recipients of a session description to participate in the session . The SDP offers and answers can be carried in SIP messages . Diameter protocol has been defined by IETF and is intended to provide an Authentication, Authorization and Accounting (AAA) framework for applications such as network access or IP mobility . Generally, for properly establishing and handling a communication connection between network elements such as a user equipment and another communication equipment or user equipment, a database, a server, etc . , one or more intermediate network elements such as control network elements , support nodes , service nodes and interworking elements are involved which may belong to different communication networks .
Various applications for end users can be offered on top of the IMS . One application is voice over IP (VoIP) which can be implemented in several different ways . Some VoIP applications can support handing over an active VoIP session to a circuit switched (CS) network, whereas some VoIP applications do not support interworking with the CS network . User Equipment (UE) , for example, a mobile terminal, can support the use of more than one VoIP applications simultaneously and the UE and the network must have common understanding on handover capability of an active session, and especially, when the UE has several active session parallel .
Service continuity (SC) describes ATCF allocation proce¬ dure and one of the ATCF allocation principles defines that in case of multiple registrations from the UE from multiple access networks, an SCC AS shall only receive and use one STN-SR, from an ATCF in the mobile network .
However, specifications do not describe how it is ensured that the SCC AS can receive only one STN-SR. Summary of the invention Embodiments of the present invention can overcome some of above drawbacks by providing an apparatus , a method and a computer program product comprising obtaining an indication of a packet data network interface for a us¬ er, and, allocating an access transfer control function for the user, wherein the allocating comprises to allocate the access transfer control function for the user if the indication of the packet data network interface indicates internet protocol multimedia subsystem (IMS) . The allocating can comprise not to allocate the access transfer control function for the user if the indication of the packet data network interface does not indicate internet protocol multimedia subsystem (IMS) . The indication of the packet data network interface can comprise an access point name (APN) .
The obtaining the indication can comprises one of :
- receiving the indication from a policy and/or charging entity (PCRF) , and,
- deducing the indication from an internet protocol address of the user .
The access transfer control function can comprise an en- tity being capable of :
- allocating a session transfer number - single .radio (STN-SR) for the user, and/or - involving itself in a SIP signaling path for a session of the user to perform access transfer related operations for the session .
Further, an apparatus , a method and a computer program product are provided, comprising receiving an indication of a communication service associated with a user, and, allocating an access transfer control function for the user, wherein the allocating comprises to allocate the access transfer control function for the user if the indication of the communication service indicates a conversational voice service .
The allocating can comprise not to allocate the access transfer control function for the user if the indication of the packet data network interface does not indicate a conversational voice service .
The indication of the communication service can comprise at least one of :
- an IMS communication service identifier ( ICS I ) and,
- IMS Application Reference Identifier ( IARI ) .
The receiving the indication can comprise receiving in a session initiation protocol request from the user (SIP INVITE, SIP REGISTER) .
Further, an apparatus , a method and a computer program product are provided, comprising obtaining an indication of a packet data network interface for a user, and, de¬ ciding if an access transfer control function is to be allocated for the user, wherein the deciding comprises allocating the access transfer control function for the user if the indication of the packet data network interface indicates internet protocol multimedia subsystem (IMS) . The deciding can comprise not to allocate the access transfer control function for the user if the indication of the packet data network interface does not indicate internet protocol multimedia subsystem (IMS) . Further, an apparatus , a method and a computer program product are provided, comprising receiving an indication of a communication service associated with a user, and, deciding if an access transfer control function is to be allocated for the user, wherein the deciding comprises allocating the transfer control function for the user if the indication of the communication service indicates a conversational voice service .
The deciding can comprises not to allocate the access transfer control function for the user if the indication of the communication service does not indicate a conversational voice service .
Embodiments of the present invention may have one or more of following advantages :
- Ensure that only one ATCF is allocated for a user, when the user is performing multiple registrations for 3GPP mobile access .
- No UE or SCC AS impact .
- Even multiple SIM/ IMS stacks of UE can use IMS
APN.
Description of drawings Figure 1 illustrates architecture and interfaces between relevant network elements according to aspects of the invention .
Figure 2 illustrates examples of internal structure and functions of apparatuses implementing aspects of the invention .
Figures 3 and 4 illustrate processes according to aspects of the invention .
Figure 5 shows signaling according to aspects of the in¬ vention .
Figure 6 illustrate architecture and interfaces between relevant network elements according to aspects of the invention .
Figure 7 illustrates identification of IMS applications relevant for aspects of the inventions .
Figures 8 and 9 illustrate processes according to aspects of the invention .
Detailed description of the invention
Different types of network entities and functions exist in the IMS network . Call Session Control Functions (CSCF) implement a session control function in SIP layer. The CSCF can act as Proxy CSCF (P-CSCF) , Serving CSCF (S-CSCF) or Interrogating CSCF (I-CSCF) . The P-CSCF is the first contact point for the User Equipment (UE) within the IMS ; the S-CSCF handles the session states in the network; the I-CSCF is mainly the contact point within an operator ' s network for all IMS connections destined to a subscriber of that network operator, or a roaming subscriber currently located within that network operator ' s service area.
The functions performed by the I-CSCF are, for example, assigning an S-CSCF to a user performing a SIP registration and routing SIP requests received from another network towards the S-CSCF . The S-CSCF can perform the session control services for the UE . It maintains a session state as needed by the network operator for support of the services and ma be acting as Registrar, i.e. it accepts registration requests and makes its information available through the location server (e.g. HSS) . The S- CSCF is the central point to users that are hosted by this S-CSCF . The S-CSCF can provide services to registered and unregistered users when it is assigned to these users . This assignment can be stored in the Home Sub¬ scriber Server (HSS ) .
In an IMS registration with a CSCF, user equipment (UE) registers itself to a CSCF for a specific time, and the CSCF becomes the UE ' s serving CSCF (S-CSCF) . The time for which the UE is registered in the CSCF is called registration lifetime . For the registration lifetime a binding can be created between the Contact address (IP address ) of the UE and the public user identities of the user (both can be provided in the registration request) .
Universal mobile telecommunications system (UMTS) ter¬ restrial radio access network (UTRAN) is radio access network (RAN) which consists of radio network controllers (RNC) and base transceiver stations (BTS) and which is located between the Iu interface and the wideband code division multiple access ( CDMA) radio interface .
Serving GPRS support node (SGSN) is a general packet ra- dio service (GPRS) support node that serves GPRS mobile stations by sending or receiving packets via a base station subsystem or a radio access network . The SGSN is the basic element of the GPRS infrastructure . It can store for each mobile in its context different parame- ters used to route the packets, for example information about the mobile ' s location .
IP connectivity access network (IP-CAN) is set of network entities and interfaces that can provide connectiv ity for IP transport between UE and the IMS .
For example, a GPRS network can be used as an IP-CAN .
High-speed packet access (HSPA) is a set of mobile tele phone communication protocols for the radio interface with high data rates .
Long-term evolution (LTE) and evolved UTRAN (E-UTRAN) are an evolution effort within the 3GPP to improve the UMTS standard to cope with future requirements , providing a high-data-rate , low-latency, and packet-optimised radio-access network .
A packet data network gateway ( P-G , PDN gateway, PDN GW) is a gateway that can provide a permanent IP-based point of attachment for access via the evolved UTRAN .
Evolved node B (eNodeB) is a base transceiver station that controls all radio-related functions in the radio access part of the evolved UTRAN (E-UTRAN) . Multimedia telephony service (MMTel) is 3GPP specified enhanced telephone service that is based on the IMS and that provides network operators with the tools to build converged fixed and mobile voice over IP services with multimedia support . The MMtel service can use the media capabilities such as voice ; real-time video ; text ; file transfer; and sharing of pictures , audio , and video clips . The number of supplementary services has been specified for the multimedia telephony service .
IMS communication service identifier ( ICSI ) is a fea¬ ture-tag that indicates that a UE supports the MMtel. The UE itself is not aware of the ICSI of a session be cause a P-CSCF removes the P-Asserted-Service header from SIP signaling towards the UE .
IMS service continuity (SC) provides the capability of continuing ongoing communication sessions with multiple media across different access networks or across different UEs under the control of the same subscriber . A service centralization and continuity application server (SCC-AS) is an AS responsible for service continuity in¬ cluding single radio voice call continuity (SR VCC) , which is a handover between a packet-switched ( PS ) access and a circuit-switched (CS) access .
Quality of service (QoS) class indicator (QCI) is an in dicator that is used as a reference to the access-node- specific parameters that control the treatment of bearer-level packet forwarding and that the operator who owns the node has preconfigured. The QCI can refer, for example, to scheduling weights , admission thresholds , queue management thresholds, and link layer protocol configurations. A subset of QoS class indicators is typically standardised to support global roaming. For conversational voice solutions, e.g. MMtel, QCI is set to value 1.
Access point name (APN) is a logical name that describes the actual connected access point (AP) to the external packet data network according to domain name system naming conventions . The APN is composed of a mandatory net- work identifier and an optional operator identifier . For example, in GPRS backbone network, APN is a reference to the gateway GPRS support node (GGSN) to be used. Gener¬ ally, access point (AP) refers to a physical device that can connect wired and wireless network parts together . The APN indicates a packet data network interface for user traffic .
Voice over LTE VoLTE, as defined by GSM Association (GSMA) , describes a protocol profile for IMS/SIP based voice over LTE service . VoLTE SIP protocol is based on
MMtel, but contains also some further definitions on top of MMtel . One such detail is the use of APN . An IMS specific APN is used for VoLTE which means that a "well- known" APN has been defined for the IMS . This APN name is "IMS", which is also the APN Network Identifier part of the full APN . The APN Operator Identifier part of the full APN depends on the public land mobile network ( PLMN) whose packet gateway ( PGW) the UE is anchored to . The "well-known" IMS APN can be provisioned as the de- fault APN for the IMS subscriber, meaning that there is no need to configure it to the device or the serving network . The use of IMS APN ensures the voice sessions are provided in local breakout (LBO) ) manner, i.e. the IP address is allocated from the serving network, and voice media can be routed directly between the serving networks , without routing it to the home network at first . Another detail is the description on how to use the LTE / evolved packet system (EPS) bearers . In VoLTE the voice media uses the QCI value 1 bearer, which is a guaranteed bit rate (GBR) bearer . This ensures a certain QoS for voice media, and also single radio voice call continuity (SRVCC) can be offered.
Rich Communication Suite (RCS ) is another GSMA SIP/IMS service profile, but for Presence, Instant Message (IM) chatting, video sharing, image sharing, etc non-real time type of communication . RCS can support also the VoLTE in addition to the previously listed non-real time media types . In RCS 4.0, the RCS can be combined in two ways with the VoLTE application; 1 ) RCS + VoLTE client is integrated with the mobile handheld device,
"intergrated client" or 2 ) RCS + VoLTE is offered separate to the mobile cellular modem hardware, "splitted client" . An example of the latter is e.g. when RCS+VoLTE runs in PC laptop, and LTE radio is offered as universal serial bus (USB) modem . In the former scenario, the RCS+VoLTE client uses the IMS APN and in the latter sce¬ nario it uses any APN which provides the Internet connectivity, e.g. "Internet" .
An Access Transfer Control Function (ATCF) is a function in a serving network (in a visited network if a user is roaming) . An ATCF can be included in the session path for the duration of a session before and after an access transfer . The ATCF can be co-located, for example, with the P-CSCF . Functions of the ATCF can include :
allocate a STN-SR;
include itself for a SIP sessions of the user; and perform the access transfer related operations and communicate with an SCC AS.
When implementing multiple VoIP solutions on top of the IMS , a problem has been raised how the SCC AS which anchors the IMS sessions for SRVCC, determines whether the session is a candidate for SRVCC or not . In order to trigger the SRVCC, the voice media must use QCI=1 GBR bearer . This in turn means , that no other service than IMS voice which is applicable for SRVCC, shall use QCI=1 bearer . The QCI value is used in EPS bearer level, the enodeB can determine the QCI value when it makes a deci¬ sion on whether to initiate SRVCC or not . Currently the UE and SCC AS do not use the QCI=1 to val¬ idate the session for SRVCC . This is not a problem as long as the operator offers only one kind of voice service to a particular user; either all operator offered voice sessions are applicable for SRVCC, or none of them are. In this way the UE and SCC AS have a common understanding about the applicability of SRVCC . In this case, e.g. the media description negotiated in session description protocol (SDP) offer/answer (contains audio media with bi-directional speech codec, e.g. adaptive multi-rate (AMR) speech codec) , and/or the IMS service identifier ( ICSI ) (e.g. ICSI=MMtel) are sufficient to determine whether the IMS session is applicable for SRVCC . But when RCS 4.0 is introduced, it may be that the same user is able to make VoLTE voice sessions (which should be applicable for SRVCC) , and RCS-VoLTE voice sessions e.g. via PC client and USB modem, which should not be applicable for SRVCC . The SDP details and the IMS service identifiers are identical for these two kinds of sessions, thereby the SCC-AS has no means to differentiate between the two services.
As long as these sessions do not occur simultaneously, the only problem is the SCC AS must anchor both kinds of sessions (because it is not able to distinguish them) , but this is only a minor performance issue, if any . More serious issue may occur when the user is able to estab¬ lish both kinds of sessions simultaneously . In this case, it may be the UE understands that RCS-VoLTE sessions it has initiated are not applicable for SRVCC, but the SCC AS does not have this information . This means when the SRVCC event takes place, i.e. the UE is moving from LTE coverage to UTRAN/GERAN, the SCC AS may make a wrong decision on which IMS session must be transferred to the CS domain . A practical situation where this sce¬ nario happens may be when the LTE mobile device is used in a WiFi (wireless local area network (WLAN) ) tethering mode, it may establish VoLTE voice sessions at the same time when some of the tethered PC s establishes RCS-
VoLTE voice sessions, both under the same IMS user account .
Another problem is, that the home IMS network containing a termination access domain selection (T-ADS) functionality, when it makes a decision on SIP registration the where to route the incoming voice session, if there are more than one IMS registration which contain identical feature tags, the IMS network is not able to make any differentiation between the registrations . This is a problem, if the use of one registration means the incoming call becomes applicable for SRVCC, but when the oth- er registration is used, the SRVCC is not possible for this incoming session . According to an aspect of the invention, a node (SCC-AS) responsible for handover (SRVCC) decision can be made aware of a packet data network interface (APN) of a us- er . By determining that the IMS APN is used, the SCC-AS can know that the correct QCI value in this case is QCI=1 (any other APN may not get QCI=1) .
According to an aspect of the invention, only QCI=1 bearers are applicable for handover to the CS network (SRVCC) .
According to an aspect of the invention, the SCC-AS can store the APN per a session and/or user and determine based on the used APN which of sessions are applicable for SRVCC (for example, only "IMS APN" is applicable for SRVCC) .
The UE can know the APN and the QCI value as per current procedures. Thereby, according to an aspect of the invention, when both the UE and the network (SCC AS) apply the same handover criteria, i.e. the APN name and/or QCI value to determine the applicability for the SRVCC, there is no issue of wrong decision .
Various ways exist how a P-CSCF can obtain an APN . Two non limiting examples are described below :
1. The P-CSCF can obtain the APN from a policy and charging control function ( PCRF) , for example, in a Diameter signalling message (Rx interface) .
2. The P-CSCF can inspect an IP address of the UE . As explained, for voice communication the well-known IMS APN can be used. This implies that a dedicated range of IP addresses can be used in the IMS APN and the UE obtains its IP address within that dedicated range during establishment of the packet data network (PDN) connec- tions . The IP address range (per APN) information can be configured in the P-CSCF and thereby the P-CSCF can be able to detect that the IP address of the UE belongs to the specific range, for example, to the range that is used by the IMS APN.
According to an aspect of the invention, a P-CSCF can become aware of an APN during a registration procedure of UE, for example, when the UE initiates IMS registration . The P-CSCF can transmit the APN information fur- ther to a SCC AS, via an S-CSCF, e.g. as part of a SIP
REGISTER request.
According to an aspect of the invention, a possible implementation is to re-use the solution which has been defined for enhanced-SRVCC in 3GPP Rel 10, where an access transfer control function (ATCF) can allocate a session transfer number for SRVCC (STN-SR) and a SIP REGISTER can be used to carry it to a S-CSCF, which in turn can then generate a reg-event notification to a SCC-AS , carrying the STN-SR. The APN name can be carried in the similar manner from the P-CSCF via the S-CSCF to the SCC-AS , except that APN name can be determined and can be put into a SIP REGISTER by the P-CSCF. The SCC-AS can use the APN name to determine the QCI value to be used for voice media .
The P-CSCF can add its own address in a SIP REGISTER request within a PATH header . Also the APN information ma be included in the PATH header, for example, as a value of a new Uniform Resource Identifier (URI) parameter de fined for that purpose . The new URI parameter can be, for example, "g .3gpp . apn" and it can take, for example, value of "IMS", "Internet", or
"262.01. Operator . service . z" to indicate the use of the AP .
Example coding of a PATH header from the P-CSCF to an S
CSCF can be:
REGISTER sip:homel . fi SIP/2.0
Path : si : cscf1. isitedl . it ; Ir ; g .3gp . apn=IMS where "g .3gpp . apn" is a new URI parameter and "IMS" is the value of the parameter containing the APN infor¬ mation .
Once this information reaches the S-CSCF, the S-CSCF can deliver the APN information further to an SCC AS using existing capabilities .
According to an aspect of the invention, a P-CSCF can include an APN in a SIP INVITE request instead of, or in addition to, including the APN in a SIP REGISTER request. The SCC-AS can receive the APN in a SIP INVITE request .
Figure 1 shows network elements and interfaces relevant for some aspects of the invention, when UE 1 , for example, a mobile handset, communicates with a mobile core network over radio access network 2 , for example, over LTE 2 access (radio network specific components are not shown in the figure) . Bottom part of figure 1 shows the data transmission path where data packets to/ from the UE 1 traverse a packet data gateway 3 (PGW) . One or more APNs can be defined at the PGW 3 for various packet data services , for example, an IMS APN which can support voLTE . Each APN is associated with certain transmission path characteristics , e.g. QoS parameters . The IMS APN can support QoS required for conversational voice services . Alternatively, the radio access network 2 can be a HSPA access 2 or WCDMA 2 access , in which case the packet data gateway 3 can be a GGSN 3. op part of figure 1 shows IMS network elements . A Γ- CSCF 4 is the first signaling (SIP) contact point for the UE 1 in the IMS network . The P-CSCF 4 can interface the PGW 3 via a policy and charging control function ( PCRF) 5 and can thereby become aware of the APN in the transmission path (e.g. IMS APN) , for example during IMS registration of the UE 1. The P-CSCF 4 communicates with an S-CSCF 6 which is assigned for the UE 1 during the IMS registration . A SCC-AS 7 can be involved in SIP sig¬ naling path path, when service continuity is required, for example, handover of a voice call from the IMS to a CS network (e.g. SRVCC) can take place .
According to another aspect of the invention, shown in figure 5, an APN can be used to select a SIP registration when receiving a request to route a terminating session to a user . T-ADS functionality can be part of an SCC-AS 7, and the SCC-AS 7 can learn the APN as described above . The T-ADS can store the binding between the registration details (e.g. Contact IP address and globally routable user agent (UA) uniform resource iden¬ tifier (GRUU) ) and the APN . In the example of Fig 5, a user1 can first register to the network with REGISTER request 51. The REGISTER 51 can contain GRUU1 for iden- tifying a terminal device the user1 is using and APN = APN X indicates which APN used . The same userl can then register for the second time with REGISTER 52 , this time from another terminal device identified with GRUU2 and using another APN, namely IMS APN. The SCC-AS 7 can store identity, GRUU and APN information from the
REGISTER requests 51 and 52 in the memory . Next, an INVITE request 53 to route a terminating session, for example a VoLTE call, to the userl in received . The T- ADS / SCC-AS 7 can determine 54 whether the incoming session 53 is applicable for SRVCC . If the received session is applicable for SRVCC, the T-ADS / SCC-AS 7 can select 54, from earlier stored registrations 51 and 52 of the userl , an IMS registration which also supports the SRVCC, meaning an IMS registration which has been associated with the IMS APN, in this example the regis¬ tration done with REGISTER 52 (GRUU2, APN = IMS APN) . This means QCI=1 will be allocated for the incoming session . The T-ADS / SCC-AS 7 can indicate the selection to an S-CSCF 6 in INVITE request 55 towards the userl . When
GRUU is used and is different between the registrations, e.g. when the registrations 51 and 52 were initiated from different devices as in Fig 5 example, the GRUU can be used from the T-ADS / SCC-AS 7 to force the S-CSCF 6 to select a certain registration . In this example,
INVITE 55 with GRUU2 can be sent to S-CSCF 6 which forces the S-CSCF 6 to select the registration using the IMS APN, thereby enabling SRVCC . If the GRUU is the same for more than one registration which use different APNs (e.g. VoLTE and RCS client reside in the same mobile device ) , then either a new indicator can be implemented in IMS service control interface (ISC) interface, or the reg-id (Outbound, IETF RFC 5626) can be used as a fea- ture tag in the ISC interface. A new media feature tag can be defined for this purpose.
Figure 2 illustrates examples of internal structure and functions of apparatus implementing aspects of the invention . The apparatus , which can be a session control entity, for example, a P-CSCF 4 or a SCC-AS 7 can have a receiving unit 21 ( receiver) configured to receive sig¬ naling messages from UE 1 or from other network entities
(e.g. from PCRF 5, S-CSCF 6) , for example SIP REGISTER and/or INVITE requests or Diameter messages , which messages can include an indication of an APN which the UE 1 is using for accessing services of the packet data network . The apparatus can have a transmitting unit 22
(transmitter) configured to transmit signaling messages , for example, SIP REGISTER and/or INVITE requests . The transmitting unit 22 can include an indication of an APN which the UE 1 is using in the request to be transmitted, for example, in SIP REGISTER request sent by the P- CSCF 4 to an S-CSCF 6.
A processing unit 23 (processor, CP) can be configured to handle information received in signalling messages and to make session control decisions, for example, de- termining if a certain session (or session leg) is / will be applicable to a handover (e.g. SRVCC) . The processing unit 23 can make determinations and/or decisions based on the APN or QCI used for accessing services , and can perform a APN to quality class indictor (QCI ) map- ping . Various QCI values can indicate support for certain session control features, for example, QCI = 1 can indicate that the session (or session leg) is applicable for a handover to a CS network (e.g. a VoLTE session can be handed over to CS voice call) . In the P-CSCF 4 , the processing unit 23 can be configured to determine an APN based on comparing an IP address of the UE 1 to dedicated ranges of IP addresses reserved for APNs . For example, the IMS APN can have a dedicated IP address range configured at a memory unit 24 (memory) of the apparatus .
The memory unit 24 can be configured to store registration related information, for example, binding between the registration details (e.g. Contact IP, GRUU) and an indication of an APN for each registration . Alternatively, a QCI or a specific indication indicating whether SRVCC is possible can be stored, based on the AP .
All units described above in relation to figure 2 may be implemented for example using microprocessors , chips and/or other electrical components and/or by software .
A session control entity (P-CSCF 4, SCC-AS 7 ) may be physically implemented in a switch, router, server or other hardware platform or electronic equipment which can support data transmission and processing tasks , or can be implemented as a component of other existing device .
Figures 3 and 4 show example processes implementing aspects of the invention .
A further aspect of the invention relates to 3GPP SR-VCC and allocation and/or selection of an Access Transfer Control Function (ATCF) to improve performance of SRVCC. In Voice over LTE (VoLTE) and Voice over HSPA a well-known IMS APN must be used . Well-known means the APN name is pre-defined so that there is no need to configure it to the device or the serving network . Service continuity (SC) describes ATCF allocation procedure and one of the ATCF allocation principles defines that in case of multiple registrations from the UE from multi le access networks , an SCC AS shall only receive and use one STN-SR, from an ATCF in the mobile network .
However, specifications do not describe how it is en¬ sured that the SCC AS can receive only one STN-SR. Furthermore, the existing Release 11 stage-3 solution assumes that the UE is served by the same ATCF in all the registration flows in the mobile network (E-UTRAN, UTRAN, GERAN, CDMA2000) . If the registrations from the UE are for different ac¬ cesses, e.g. a 3GPP mobile access, and WL N, then a so¬ lution can be built upon on the access type, e.g. only if the ATCF is serving a 3GPP mobile access , the ATCF informs its address to the SCC AS. However, this can not work when multiple registrations are for 3GPP mobile access .
For example, as shown in Figure 6, a UE 1 may have more than one independent SIP/IMS stack which may perform IMS registration independentl . A practical example is when the SIP/IMS stack (SIP Stack 1) for VoIP is co-located in the modem chipset of the UE 1 and another SIP/IMS stack for Rich Communication Suite (RCS ) (SIP Stack 2 ) is provided by operating system of the UE 1 or applica- tion on top of the operating system. This means that two
IMS registrations can take place and more than one ATCF 8a, 8b and consequently more than one STN-SR can be allocated for the single UE 1. ATCF 81, 8b allocation process by a P-CSCF 4a, 4b can currently be based on local policy/implementation specific. As the SIP/IMS stacks are completely separate in this example, the SIP/IMS stacks can discover the P-CSCF 4a, 4b addresses independently, therefore it can be expected that each registration can use a different P-CSCF 4a, 4b address and communicates with different P-CSCFs 4a, 4b. This means any of the selected P-CSCFs 4a, 4b is not able to coordinate and/or ensure that only a single ATCF 8a, 8b is used . Therefore it is likely that each regis¬ tration gets a separate ATCF 8a, 8b allocated. It is also possible that two different PGWs 3 and PCRFs 5 are involved (not shown in Fig 6 ) .
It has been suggested that an SCC AS 7 can detect that two different ATCF 8a, 8b / STN-SRs are provided to the user and the SCC AS 7 can take action to disable ATCF functionality completely . Disabling the ATCF f nctionality completely can be considered real drawback, since the eSRVCC cannot be provided at all to the UE 1. It has also been suggested that both the SCC AS 7 and the UE 1 can maintain record of the allocated ATCF 8a, 8b and these entities can thereby ensure that new sessions will use the same ATCF functionality. This solution, however, impacts both UE 1 implementation and the network and thereby it does not work with legacy devices . According to an aspect of the invention, a P-CSCF 4a, 4b can inspect a used APN which is used to register UE 1 to the IMS network to decide whether to allocate an ATCF 8a, 8b or not. If the APN is IMS APN then the P-CSCF 4a, 4b can allocate an ATCF 8a, 8b. If the APN is not IMS APN then the P-CSCF 4a, 4b does not allocate an ATCF. The processing unit 23 (processor, CP) of Fig 2 can be configured to examine the APN and to decide if an ATCF 8a, 8b is to be allocated or not .
The P-CSCF 4a, 4b can learn the used APN as explained earlier when describing other aspects of the invention .
The solution works for multiple registrations via 3GPP mobile access, when only one of the registrations is performed via the IMS AP .
According to an aspect of the invention, a P-CSCF 4a, 4b can inspect the used IMS communication service identifier ( ICSI ) and/or IMS Application Reference Identifier ( IARI ) to decide whether to allocate ATCF 8a, 8b or not . IARI value can identify the application to be invoked. I f the ICSI and/or IARI can identif carrier grade operator voice service, such as VoLTE, then the P-CSCF 4a, 4b can allocate an ATCF 8a, 8b, otherwise it does not allocate the ATCF . The decision can be made based on the value of either ICSI or IARI alone, or, based on the combination of values of both ICSI and IARI . ICSI and/or IARI can be received by a P-CSCF 4 in a SIP request, for example, in REGISTER or INVITE request . Figure 7 shows an example of identification of applications using communication service identifier (e.g. ICSI ) and applica¬ tion reference (e.g. IARI ) . By carrier grade operator voice service a conversational voice service is meant, in other words , it is the prima¬ ry voice service of the operator, offering the QoS and service level which is comparable to CS voice (like MMTE1) . According to an aspect of the invention, if the VoLTE does not have a dedicated ICSI/IARI, then if ICSI and/or IARI identifies a service like RCS, which is known not to contain carrier grade voice, then the P-CSCF 4a, 4b does not allocate a ATCF, otherwise it can allocate a ATCF 8a, 8b. The processing unit 23 (processor, CP) of Fig 2 can be configured to inspect received ICSI and/or IARI and to decide if an ATCF 8a, 8b is to be allocated.
This aspect is beneficial if separate IMS/SIP stacks ex ist and both stacks (VoLTE and other IMS services) can use the IMS APN and/or more than one carrier grade voice services need to be offered via IMS APN, and also if e - siliency mechanism needs to be offered to VoLTE, where the VoLTE application registers multiple times via IMS APN, but with different P-CSCF 4a, 4b.
For the purpose of the present invention as described herein above, it should be noted that
- an access technology via which signaling is transferred to and from a network element or node ma be any technology by means of which a node can access an access network (e.g. via a base station or generally an access node) . Any present or future technology, such as WLAN
(Wireless Local Access Network) , WiMAX (Worldwide Interoperability for Microwave Access ) , BlueTooth, Infra¬ red, and the like may be used; although the above technologies are mostly wireless access technologies , e.g. in different radio spectra, access technology in the sense of the present invention implies also wirebound technologies, e.g. IP based access technologies like cable networks or fixed lines but also circuit switched access technologies ; access technologies may be distin- guishable in at least two categories or access domains such as packet switched and circuit switched, but the existence of more than two access domains does not impede the invention being applied thereto,
- usable access networks may be any device, apparatus, unit or means by which a station, entity or other user equipment may connect to and/or utilize services offered by the access network; such services include, among oth¬ er s, data and/or (audio-) visual communication, data download etc . ;
- a user equipment may be any device, apparatus , unit or means by which a system user or subscriber may experience services from an access network, such as a mobile phone, personal digital assistant PDA, or computer;
- method steps likely to be implemented as software code portions and being run using a processor at a network element or terminal (as examples of devices , apparatuses and/or modules thereof, or as examples of entities including apparatuses and/or modules therefor) , are soft- ware code independent and can be specified using any known or future developed programming language as long as the functionality defined by the method steps is preserved;
- generally, any method step is suitable to be imple- mented as software or by hardware without changing the idea of the invention in terms of the functionality implemented;
- method steps and/or devices , apparatuses , units or means likely to be implemented as hardware components at a terminal or network element, or any module (s) thereof, a e hardware independent and can be implemented using any known or future developed hardware technology or any hybrids of these, such as MOS (Metal Oxide Semiconductor) , CMOS (Complementary MOS), BiMOS (Bipolar MOS) , BiCMOS (Bipolar CMOS) , ECL (Emitter Coupled Logic) , TTL (Transistor-Transistor Logic) , etc . , using for example ASIC (Application Specific IC (Integrated Circuit) ) components, FPGA ( Field-programmable Gate Arrays ) compo- nents , CPLD (Complex Programmable Logic Device) components or DSP (Digital Signal Processor) components ; in addition, any method steps and/or devices , units or means likely to be implemented as software components may for example be based on any security architecture capable e.g. of authentication, authorization, keying and/or traffic protection;
- devices , apparatuses , units or means can be imple¬ mented as individual devices , apparatuses , units or means, but this does not exclude that they are imple- mented in a distributed fashion throughout the system, as long as the functionality of the device, apparatus , unit or means is preserved,
- an apparatus may be represented by a semiconductor chip, a chipset, or a (hardware) module comprising such chip or chipset ; this , however, does not exclude the possibility that a functionality of an apparatus or module, instead of being hardware implemented, be implemented as software in a (software) module such as a com¬ puter program or a computer program product comprising executable software code portions for execution/being run on a processor;
- a device may be regarded as an apparatus or as an as¬ sembly of more than one apparatus , whether functionally in cooperation with each other or functionally inde- pendently of each other but in a same device housing, for example .
The invention is not limited to session handling in the IMS network (s) , but may also be applied in other type of networks having similar kind of support for handing over a session to another access technology depending on a service type and/or characteristic of the transmission path (e.g. QoS requirements) . Functions of the session control entity described above may be implemented by code means, as software, and loaded into memory of a computer .

Claims

Claims
1. An apparatus (4), comprising :
means for obtaining (21) an indication of a packet data network interface for a user, and,
means for transmitting (22 ) the indication of the packet data network interface to a session control enti¬ ty.
2. An apparatus of claim 1 , wherein the indication of the packet data network interface comprises an access point name (APN) .
3. An apparatus of claim 1 or 2 , wherein the obtaining the indication comprises one of :
- receiving the indication from a policy and/or charging entity (PCRF) , and,
- deducing the indication from an internet protocol address of the user .
4. An apparatus of any of preceding claims , wherein the transmitting comprises transmitting the indication as part of registration procedure of the user .
5. An apparatus of any of preceding claims , wherein the transmitting comprises transmitting in a session initiation protocol REGISTER request .
6. An apparatus (7), comprising :
means for receiving (21) an indication of a packet data network interface for a user, means for determining (23) handover capability of a session of the user based on the indication of the packet data network interface .
7. An apparatus of claim 6, further comprising means for determining (23, 24 ) a quality class indication (QCI) for the session of the user based on the indication of the packet data network interface, and wherein the determining the handover capability comprises deter- mining the handover capability from the quality class indication (QCI).
8. An apparatus of claim 6 or 7, wherein the receiving comprises receiving the indication as part of registration procedure of the user .
9. An apparatus of any of claims 6 - 8 , wherein the indication of the packet data network interface compris es an access point name (APN) .
10. An apparatus of any of claims 6 - 9, wherein the determining the handover capability comprises determining applicability for single radio voice call continuit (SR-VCC) .
11. An apparatus of any of claims 6 - 10, wherein the determining the handover capability comprises determining that the session is capable for a handover when the indication of the packet data network interface indi- cates Λ IMS' or internet protocol multimedia subsystem, or, when the determined quality class indication (QCI ) indicates value 1.
12. An apparatus of any of claims 6 - 11, further comprising means for maintaining (24 ) information about at least one registration of the user, wherein the information comprises an indication of a packet data network interface for each of the at least one registration .
13. An apparatus of any of claim 12 , further comprising means for receiving (21 ) a request to terminate a ses¬ sion to the user, and, means for selecting (23) a registration of the user from the at least one registration of the user for terminating the session towards the user, based on the maintained indication of a packet data network interface for each of the at least one registration of the user .
14. A method, comprising :
obtaining ( 32 ) an indication of a packet data network interface for a user, and,
transmitting ( 33 ) the indication of the packet data network interface to a session control entity .
15. A method of claim 14, wherein the obtaining the indication comprises one of :
- receiving the indication from a policy and/or charging entity (PCRF) , and,
- deducing the indication from an internet protocol address assigned for the user .
16. A method of claim 14 or 15 , wherein the transmit- ting comprises transmitting the indication as part of registration procedure of the user .
17. A method, comprising : receiving (41) an indication of a packet data network interface for a user,
determining (44) handover capability of a session of the user based on the indication of the packet data network interface .
18. A method of claim 17, further comprising determining (42) a quality class indication (QCI ) for the ses¬ sion of the user based on the indication of the packet data network interface, and wherein the determining comprises determining the handover capability from the quality class indication (QCI ) .
19. A method of claim 17 or 18 , wherein the receiving comprises receiving the indication as part of registra¬ tion procedure of the user .
20. A method of any of claims 17 - 19, wherein the determining the handover capability comprises determining that the session is capable for a handover when the indication of the packet data network interface indicates A IMS' or internet protocol multimedia subsystem, or, when the determined quality class indication (QCI ) indi¬ cates value 1.
21. A method of any of claims 17 - 20 , further comprising maintaining ( 43 ) information about at least one registration of the user, wherein the information comprises an indication of a packet data network interface for each of the at least one registration .
22. A method of claim 21, further comprising receiving (44) a request to terminate a session to the user, and, selecting ( 44 ) a registration of the user from the at least one registration of the user for terminating the session towards the user, based on the maintained indication of a packet data network interface for each of the at least one registration of the user .
23. A computer program product comprising code means adapted to produce steps of any of claims 14-22 when loaded into the memory of a computer .
24. An apparatus (4, 4a, 4b) , comprising :
means for obtaining (21) an indication of a packet data network interface for a user, and,
means for allocating (23) an access transfer control function (8a, 8b) for the user, wherein the means for allocating (23) is configured to allocate the access transfer control function ( 8a, 8b) for the user if the indication of the packet data network interface indicates internet protocol multimedia subsystem (IMS) .
25. An apparatus of claim 24, wherein the means for allocating (23) is configured not to allocate the access transfer control function (8a, 8b) for the user if the indication of the packet data network interface does not indicate internet protocol multimedia subsystem (IMS).
26. An apparatus of claim 24 or 25 , wherein the indication of the packet data network interface comprises an access point name ( PN) .
27. An apparatus of any of claims 24 - 26, wherein the obtaining the indication comprises one of :
- receiving the indication from a policy and/or charging entity (PCRF) , and, - deducing the indication from an internet protocol address of the user .
28. An apparatus of any of claims 24 - 27, wherein the access transfer control function comprises an entity being capable of :
- allocating a session transfer number - single radio (STN-SR) for the user, and/or
- involving itself in a SIP signaling path for a session of the user to perform access transfer related operations for the session .
29. An apparatus (4, 4a, 4b) , comprising :
means for receiving (21) an indication of a communication service associated with a user, and,
means for allocating (23) an access transfer control function ( 8a, 8b) for the user, wherein the means for allocating (23) is configured to allocate the access transfer control function ( 8a, 8b) for the user if the indication of the communication service indicates a conversational voice service .
30. An apparatus of claim 29, wherein the means for al¬ locating (23) is configured not to allocate the access transfer control function ( 8a, 8b) for the user if the indication of the packet data network interface does not indicate a conversational voice service .
31. An apparatus of claim 29 or 30, wherein the indication of the communication service comprises at least one of:
- an IMS communication service identifier ( ICS I ) and,
- IMS Application Reference Identifier (IARI).
32. An apparatus of any of claims 29 - 31, wherein the receiving the indication comprises receiving in a session initiation protocol request from the user (SIP INVITE, SIP REGISTER) .
33. A method, comprising :
obtaining (81) an indication of a packet data net¬ work interface for a user, and,
deciding ( 82 ) if an access transfer control function (8a, 8b) is to be allocated for the user, wherein the deciding comprises allocating ( 83 ) the access trans¬ fer control function (8a, 8b) for the user if the indication of the packet data network interface indicates internet protocol multimedia subsystem (IMS) .
34. A method of claim 33 , wherein the deciding ( 82 ) comprises not to allocate (84) the access transfer control function ( 8a, 8b) for the user if the indication of the packet data network interface does not indicate internet protocol multimedia subsystem (IMS) .
35. A method, comprising :
receiving ( 91 ) an indication of a communication service associated with a user, and,
deciding (92) if an access transfer control function (8a, 8b) is to be allocated for the user, wherein the deciding comprises allocating (93) the access transfer control function (8a, 8b) for the user if the indi- cation of the communication service indicates a conversational voice service .
36. A method of claim 35 , wherein the deciding ( 82 ) comprises not to allocate (84) the access transfer con- trol function (8a, 8b) for the user if the indication the communication service does not indicate a conversa tional voice service .
37. A computer program product comprising code means adapted to produce steps of any of claims 33-36 when loaded into the memory of a computer .
PCT/EP2012/071557 2011-11-14 2012-10-31 Method and apparatus for allocating a transfer function WO2013072193A2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP2011070050 2011-11-14
EPPCT/EP2011/070050 2011-11-14

Publications (2)

Publication Number Publication Date
WO2013072193A2 true WO2013072193A2 (en) 2013-05-23
WO2013072193A3 WO2013072193A3 (en) 2013-07-11

Family

ID=47178610

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2012/071557 WO2013072193A2 (en) 2011-11-14 2012-10-31 Method and apparatus for allocating a transfer function

Country Status (1)

Country Link
WO (1) WO2013072193A2 (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015174018A1 (en) * 2014-05-13 2015-11-19 パナソニック インテレクチュアル プロパティ コーポレーション オブ アメリカ Network node and signaling processing method
EP3029908A4 (en) * 2013-09-04 2016-07-27 Huawei Tech Co Ltd Service authority determination method and device
WO2016141976A1 (en) * 2015-03-10 2016-09-15 Telefonaktiebolaget Lm Ericsson (Publ) Access network determination
DE102015108507A1 (en) * 2015-05-29 2016-12-01 Deutsche Telekom Ag Devices and methods for managing mobile radio terminals
JP2017514337A (en) * 2014-03-26 2017-06-01 インテル アイピー コーポレイション Network access selection based on internet protocol media subsystem service
WO2018035177A2 (en) 2016-08-15 2018-02-22 Parallel Wireless, Inc. Convergence proxy for core network virtualization
US11252632B2 (en) 2016-08-15 2022-02-15 Parallel Wireless, Inc. VoIP and native carrier call integration

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106465250B (en) * 2014-03-06 2019-11-08 诺基亚技术有限公司 Method and apparatus for determining the IMS connectivity by non-3 GPP access network

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2413464A (en) * 2004-04-21 2005-10-26 Orange Sa An inter-working unit with a protocol conversion or protocol encapsulation function, for use with dual stack user equipment on a packet radio network
GB2424543A (en) * 2005-03-22 2006-09-27 Orange Personal Comm Serv Ltd Telecommunication Apparatus and Method
JP5016100B2 (en) * 2007-03-30 2012-09-05 テレフオンアクチーボラゲット エル エム エリクソン（パブル） Circuit switching access notification system and method in IMS registration

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3029908A4 (en) * 2013-09-04 2016-07-27 Huawei Tech Co Ltd Service authority determination method and device
JP2017514337A (en) * 2014-03-26 2017-06-01 インテル アイピー コーポレイション Network access selection based on internet protocol media subsystem service
WO2015174018A1 (en) * 2014-05-13 2015-11-19 パナソニック インテレクチュアル プロパティ コーポレーション オブ アメリカ Network node and signaling processing method
JPWO2015174018A1 (en) * 2014-05-13 2017-04-20 パナソニック インテレクチュアル プロパティ コーポレーション オブ アメリカＰａｎａｓｏｎｉｃ Ｉｎｔｅｌｌｅｃｔｕａｌ Ｐｒｏｐｅｒｔｙ Ｃｏｒｐｏｒａｔｉｏｎ ｏｆ Ａｍｅｒｉｃａ Network node and signaling processing method
WO2016141976A1 (en) * 2015-03-10 2016-09-15 Telefonaktiebolaget Lm Ericsson (Publ) Access network determination
DE102015108507A1 (en) * 2015-05-29 2016-12-01 Deutsche Telekom Ag Devices and methods for managing mobile radio terminals
DE102015108507B4 (en) 2015-05-29 2020-08-06 Deutsche Telekom Ag Devices and methods for managing mobile radio terminals
WO2018035177A2 (en) 2016-08-15 2018-02-22 Parallel Wireless, Inc. Convergence proxy for core network virtualization
EP3498043A4 (en) * 2016-08-15 2020-08-05 Parallel Wireless Inc. Convergence proxy for core network virtualization
US10856362B2 (en) 2016-08-15 2020-12-01 Parallel Wireless, Inc. Convergence proxy for core network virtualization
US11252632B2 (en) 2016-08-15 2022-02-15 Parallel Wireless, Inc. VoIP and native carrier call integration

Also Published As

Publication number Publication date
WO2013072193A3 (en) 2013-07-11

Similar Documents

Publication Publication Date Title
US11171996B2 (en) Low latency IMS-based media handoff between a cellular network and a WLAN
WO2013072193A2 (en) Method and apparatus for allocating a transfer function
CN102177698B (en) Correlating communication sessions
US8885603B2 (en) Handover of calls between access networks
US8848666B2 (en) Handover of emergency calls from a circuit switched to a packet switched access network
US20060246903A1 (en) System and method for voice data handoff between cellular network and WiBro/WLAN network in heterogeneous network environment
US10966260B2 (en) Device, system and method for VoLTE setup
US20120185600A1 (en) Control of Codec Negotiation for Communication Connection
US20110211525A1 (en) Session transfer between different access network types
US8380211B2 (en) CS domain call terminating system, method and network device
US9055397B2 (en) Method for usage of VPLMN infrastructure by an HPLMN to terminate an IMS session set up for a roaming user
KR101148036B1 (en) Method and system for handover to WLAN network from LTE network
CN101779495A (en) Methods, apparatuses and computer program product for access domain selection for the media channel and the session control channel
US9509725B2 (en) Method and apparatus for indicating a type of a network interface
EP3078226B1 (en) Method and apparatus for requesting an initial attachment of a ue to ps mobile communication network
US8078180B2 (en) Subscriber server system for a cellular communication system
US9294332B2 (en) Method and apparatus for IUT in a wireless communication system
US20110096746A1 (en) Method, Apparatus, System and Related Computer Program Product for Handover Management
EP2775689A1 (en) Method and apparatus for iut in a wireless communication system
US20180160290A1 (en) Method and device for processing a signaling message related to a communication service of a client device
JP5633947B2 (en) Emergency service registration method and apparatus for packet data connection
KR101064758B1 (en) Method and Apparatus for providing VoIP service guaranteeing Qos
EP2774352B1 (en) A method and apparatus for indicating a type of a network interface
KR100965005B1 (en) Apparatus and method for managing call session under IP based network
EP4128681A1 (en) Interworking of mission critical services with public networks

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 12786884

Country of ref document: EP

Kind code of ref document: A2

122 Ep: pct application non-entry in european phase

Ref document number: 12786884

Country of ref document: EP

Kind code of ref document: A2