WO2010091715A1

WO2010091715A1 - Devices for an improved multi access system

Info

Publication number: WO2010091715A1
Application number: PCT/EP2009/051495
Authority: WO
Inventors: Stefan Rommer; John Stenfelt; Lars Gunnar LÖVSÉN
Original assignee: Telefonaktiebolaget L M Ericsson (Publ)
Priority date: 2009-02-10
Filing date: 2009-02-10
Publication date: 2010-08-19

Abstract

A user terminal, a UE (105), for a cellular communications system (100), the UE (105) being arranged to transmit, on an access network of a first type, a QoS signalling message to a mobility anchor (125) in the system (100), the UE (105) being characterized in that it is also arranged to include information regarding a second access network type in the bearer management signalling message, by means of which the UE (105) is arranged to signal to the mobility anchor (125) that the second access network type should be used for an IP packet flow which is also specified in the bearer management signalling message. The invention also discloses a corresponding receiving UE, and a transmitting and a receiving mobility anchor.

Description

DEVICES FOR AN IMPROVED MULTI ACCESS SYSTEM

TECHNICAL FIELD

The present invention discloses a user terminal and a mobility anchor for a cellular communication system, which provide the system with improved multi access characteristics.

BACKGROUND

In cellular communications systems, the scenario where a terminal, "UE", User Equipment, can get access via a number of different access network technologies is becoming more and more common. For example, mobile phones often come equipped with both cellular and WLAN access capabilities, and laptop computers often have Ethernet, WLAN and sometimes also cellular access capabilities. Typically, these different access networks are only used one at a time, and more importantly, a given service or a given IP session only uses one access network at a time.

Currently 3GPP EPS (also known as 3GPP SAE) is defining solutions for how session continuity can be achieved when a UE moves between different access networks. This can e.g. mean that a service that is running over a cellular access network is moved to run over a WLAN access instead. However, with this solution as well, the UE only uses one access network at a time, and during an access network change, the whole IP session and all running services within that IP session is moved from source access to target access. Simultaneous use of multiple accesses (a.k.a. "multi-homing") is not supported, except for very short times during a handover between two access networks.

There is work ongoing in IETF, and related work being started up in 3GPP, for defining mobility solutions in multi-homing scenarios. As part of this work, the concept of "flow mobility" is investigated, i.e. only a subset of the IP packet flows for a given IP session is moved from one access to another. For example, it could be that only the video component of a multimedia call is moved from cellular access to WLAN, while the IP packet flows related to the voice component of the same call stays in the cellular access network.

The IETF work focuses on how multiple simultaneous accesses can be supported for MIPvθ. Future work will likely investigate a similar scenario also for PMIPvθ.

SUMMARY The present invention aims at providing a solution by means of which multiple IP packet flows can be routed between a UE and a so called "mobility anchor" in the system via a plurality of access networks, so that a first IP packet flow is routed via a first access network, and a second IP packet flow is routed via a second access network.

Such a solution is provided by the present solution in that it discloses a user terminal, a UE, for a cellular communications system, which is arranged to transmit, on an access network of a first type, a QoS signalling message to a mobility anchor in the system.

The UE of the invention is also arranged to include information regarding a second access network type in the bearer management signalling message, by means of which the UE is arranged to signal to the mobility anchor that the second access network type should be used for an IP packet flow which is also specified in the bearer management signalling message.

In addition, the present invention also discloses a user terminal, a UE, for a cellular communications system, which is arranged to receive, on an access network of a first type, a QoS signalling message from a mobility anchor in the system. The UE of this embodiment of the invention is also arranged to detect and correctly act upon information regarding a second access network type in the bearer management signalling message, by means of which the mobility anchor has signalled to the UE that the second access network type should be used for an IP packet flow which is also specified in the bearer management signalling message.

The invention also discloses a corresponding mobility anchor, i.e. a mobility anchor for a cellular communications system which is arranged to receive, correctly interpret and act upon a QoS signalling message sent on an access network of a first kind from a UE, a user terminal, in the system.

The mobility anchor is also arranged to correctly interpret and act upon information regarding a second access network type in the QoS signalling message, by means of which the UE has indicated to the mobility anchor that the second access network type should be used for an IP packet flow which is also specified in the QoS signalling message.

In addition, the invention also discloses a mobility anchor for a cellular communications system which is arranged to transmit on an access network of a first kind to a UE, a user terminal, in the system, a QoS signalling message.

The mobility anchor of this embodiment is also arranged to include information regarding a second access network type in the QoS signalling message, by means of which the mobility anchor indicates to the UE that the second access network type should be used for an IP packet flow which is also specified in the QoS signalling message.

Thus, by means of the invention, a UE or a mobility anchor is able to signal to the other part (mobility anchor/UE) on a first access network which allows this, that an IP flow should be established on a second access network which does not have facilities for such signalling.

In one embodiment of the UE of the invention, the first and second access network types are different types of access networks.

!n one embodiment of the UE of the invention, the second access network type is chosen from among the following: WLAN and DSL.

In one embodiment of the UE of the invention, the first access network type is chosen from among the following: GERAN (2G), UTRAN (3G), E-UTRAN (LTE), HSPA and WiMAX, CDMA 2000 and HRPD.

In one embodiment of the UE of the invention, the first and second access network types are the same type of access networks.

In one embodiment of the UE of the invention, the QoS management signalling message comprises bearer management signalling.

In one embodiment of the invention, the mobility anchor is a PDN-GW (Packet Data Network) in a GERAN (2G) UTRAN (3G) or an E-UTRAN (LTE) system.

In one embodiment of the mobility anchor of the invention, the first and second access network types are different types of access networks.

In one embodiment of the mobility anchor of the invention, the second access network type is chosen from among the following: WLAN and DSL.

In one embodiment of the mobility anchor of the invention, the first access network type is chosen from among the following: GERAN (2G), UTRAN (3G), E-UTRAN (LTE), HSPA and WiMAX, CDMA 2000 and HRPD. in one embodiment of the mobility anchor of the invention, the first and second access network types are the same type of access networks.

In one embodiment of the mobility anchor of the invention, the QoS signalling comprises bearer management signalling.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in more detail in the following, with reference to the appended drawings, in which

Fig 1 shows a system in which the present invention can be applied.

DETAILED DESCRIPTION Fig 1 shows an overview of a system 100 for which the present invention is intended. The system 100 comprises a so called "mobility anchor", in this case a PDN-GW, a Packet Data Network Gateway 125, and can accommodate a number of user terminals, UEs, one of which is shown as 105 in fig 1.

As shown in fig 1 , the UE 105 and the PDN-GW 125 exchange IP packet flows, with a first flow, "Flow 1" being exchanged on a first Access Network, AN 1 , 110, such as for example a GERAN ("2G") or UTRAN ("3G") network, while a second flow, "Flow 2" is exchanged on a second access network, AN 2, 120, such as, for example a WLAN network.

In order for the second flow to be able to be exchanged on, for example, a WLAN network, the invention proposes to "re-use" the access network specific rules language that are available in some access network to transport routing rules also for those access networks that do not have access network specific means to negotiate routing rules. For example, the 3GPP-specific language to negotiate TFTs between UE and NW can be expanded so that routing rules (packet filters) applying to non-3GPP accesses can be transported over the 3GPP access as well. This means that the TFT language for 3GPP accesses is not just used to provide rules for how to map IP flows onto 3GPP bearers, but also for how to map IP flows onto different accesses. Similar extensions can also be done for other accesses, e.g. cdma2000, HRPD and WiMAX.

A suitable pre-requisite of the proposal is that the UE has at least one access network active where routing rules can be exchanged. This is however likely since the cellular access networks that typically have this capability are wide area access networks. On the other hand, access networks without the capabilities such as WLAN and DSL typically only have local area coverage.

The proposal is to re-use the access network specific rules language that are available in some access networks to transport routing rules also for those access networks that do not have access network specific means to negotiate routing rules.

For 3GPP accesses the TFT and TAD parameters are extended to include also access network type information. For other access networks, the access network specific routing rules language can be extended in a similar fashion. In the remainder of this section we will use the generic term "routing rule description" (RRD) to denote the structure that describes how IP flows are routed onto certain access networks and/or QoS bearers. For 3GPP access networks, the RRD could be realized as a TAD and/or TFT.

Each packet filter in the RRD has an associated access technology type (ATT). The ATT could e.g. be WLAN, DSL, 3GPP or any other access. The ATT specifies which access is used to transfer the IP flow corresponding to the packet filter. For example, for a TAD/TFT used with 3GPP access, each filter in the TAD/TFT would be associated with an ATT. Different operations are allowed on the RRD. The existing operations for a 3GPP TAD/TFT is e.g. to add, remove or modify a packet filter and/or the associated QoS. The proposal is now to extend this to allow also modifying the associated ATT of the packet filters. Such a modification would imply that the IP flow gets moved from one access to another access.

A possible sequence of events in a system with the present invention could be as follows:

1. A UE activates a first Access Network, an AN, such as for example an UTRAN or 3G network.

2. The PDN GW acknowledges the AN.

3. The UE activates a second Access Network, an AN, such as for example a WLAN or a DSL network.

4. The UE wishes to start a certain service session via the WLAN or DSL network.

5. The UE sends a QoS signalling message to a mobility anchor such as the PDN-GW 125. The message is sent via the first access network, i.e. the UTRAN network, which allows such signalling. In this QoS message, there is also according to the invention, a field or other information regarding the fact that this particular service session or flow of IP packets, should be sent on the second access network which is established between the UE and the PDN-GW, i.e. in this example the WLAN or DSL network.

6. The UE and the PDN GW start to exchange IP packets as defined on the second AN. The QoS management signalling message can also comprise or be so called bearer management signalling, and can comprise a so called packet filter which is installed in the UE and in the PDN-GW, and enables those nodes to see on which of the available ANs that packets should be transmitted.

The "mobility anchor" mentioned above can suitably be an LTE PDN GW, but can be used as a so called GGSN in a 2G or 3G system, or as a true PDN GW in a 2G, 3G or an LTE system.

The invention is not limited to the examples of embodiments described above and shown in the drawings, but may be freely varied within the scope of the appended claims.

Claims

CUIMS

1. A user terminal, a UE (105), for a cellular communications system (100), the UE (105) being arranged to transmit, on an access network of a first type, a QoS signalling message to a mobility anchor (125) in the system (100), the UE (105) being characterized in that it is also arranged to include information regarding a second access network type in the bearer management signalling message, by means of which the UE (105) is arranged to signal to the mobility anchor (125) that the second access network type should be used for an IP packet flow which is also specified in the bearer management signalling message.

2. A user terminal, a UE (105), for a cellular communications system (100), the UE (105) being arranged to receive, on an access network of a first type, a QoS signalling message from a mobility anchor (125) in the system, the UE (105) being characterized in that it is also arranged to detect and correctly act upon information regarding, a second access network type in the bearer management signalling message, by means of which the mobility anchor (125) has signalled to the UE (105) that the second access network type should be used for an IP packet flow which is also specified in the bearer management signalling message.

3. The UE (105) of claim 1 and 2, in which the first and second access network types are different types of access networks.

4. The UE (105) of any of claims 1-3, in which the second access network type is chosen from among the following: WLAN and DSL.

5. The UE (105) of any of claims 1-4, in which the first access network type is chosen from among the following: GERAN (2G), UTRAN (3G), E-UTRAN

(LTE), HSPA and WiMAX, CDMA 2000 and HRPD.

6. The UE (105) of claim 1, in which the first and second access network types are the same type of access networks.

7. The UE (105) of any of claims 1-6, in which the QoS management signalling message comprises bearer management signalling.

8. A mobility anchor (125) for a cellular communications system (100), the mobility anchor (125) being arranged to receive, correctly interpret and act upon a QoS signalling message sent on an access network of a first kind from a UE (105), a user terminal, in the system, the mobility anchor (125) being characterized in that it is also arranged to correctly interpret and act upon information regarding a second access network type in the QoS signalling message, by means of which the UE (105) has indicated to the mobility anchor (125) that the second access network type should be used for an IP packet flow which is also specified in the QoS signalling message.

9. A mobility anchor (125) for a cellular communications system (100), the mobility anchor (125) being arranged to transmit on an access network of a first kind to a UE (105), a user terminal, in the system, a QoS signalling message, the mobility anchor (125) being characterized in that it is also arranged to include information regarding a second access network type in the QoS signalling message, by means of which the mobility anchor (125) indicates to the UE (105) that the second access network type should be used for an IP packet flow which is also specified in the QoS signalling message.

10. The mobility anchor (125) of claim 8 or 9, being a PDN-GW in a GERAN (2G) UTRAN (3G) or an E-UTRAN (LTE) system,

11 The mobility anchor (125) of any of claims 8-10, in which the first and second access network types are different types of access networks*

12. The mobility anchor (125) of any of claims 8-11, in which the second access network type is chosen from among the following: WLAN and DSL.

13. The mobility anchor (125) of any of claims 8-12, in which the first access network type is chosen from among the following: GERAN (2G), UTRAN

(3G)₁ E-UTRAN (LTE), HSPA and WiMAX₁ CDMA 2000 and HRPD.

14. The mobility anchor (125) of claim 8 or 9, in which the first and second access network types are the same type of access networks.

15. The mobility anchor (125) of any of claims 8-14, in which the QoS signalling comprises bearer management signalling.