U.S. patent application number 14/571584 was filed with the patent office on 2015-04-09 for radio communication system, method and arrangement for use in a radio communication system.
The applicant listed for this patent is Telefonaktiebolaget L M Ericsson (publ). Invention is credited to Gunnar Mildh, Jari VIKBERG, Erik WESTERBERG.
Application Number | 20150099488 14/571584 |
Document ID | / |
Family ID | 49551054 |
Filed Date | 2015-04-09 |
United States Patent
Application |
20150099488 |
Kind Code |
A1 |
Mildh; Gunnar ; et
al. |
April 9, 2015 |
Radio Communication System, Method and Arrangement for Use in a
Radio Communication System
Abstract
A system includes a first access network arranged to operate
according to a first Radio Access Technology, a second access
network arranged to operate according to a second Radio Access
Technology, and a user device which is connectable to the first
access network and to the second access network. The system also
includes an authentication node arranged to identify the user
device, when seeking access to the second access network, through a
user device identifier for the user device, wherein the user device
identifier is associated with the first access network. A query
node provides information about a context of the user device in the
first access network based on the user device identifier. An access
selection node generates an access selection decision for the
access sought by the user device to the second access network based
on the provided context, and the access selection decision is then
executed.
Inventors: |
Mildh; Gunnar; (Sollentuna,
SE) ; VIKBERG; Jari; (Jarna, SE) ; WESTERBERG;
Erik; (Enskede, SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Telefonaktiebolaget L M Ericsson (publ) |
Stockholm |
|
SE |
|
|
Family ID: |
49551054 |
Appl. No.: |
14/571584 |
Filed: |
December 16, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13697767 |
Nov 13, 2012 |
8942763 |
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PCT/SE2012/051007 |
Sep 24, 2012 |
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14571584 |
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61644040 |
May 8, 2012 |
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Current U.S.
Class: |
455/411 |
Current CPC
Class: |
H04W 92/02 20130101;
H04W 12/08 20130101; H04W 48/16 20130101; H04W 48/18 20130101; H04W
88/10 20130101; H04W 76/10 20180201; H04W 84/12 20130101; H04W
88/06 20130101 |
Class at
Publication: |
455/411 |
International
Class: |
H04W 12/08 20060101
H04W012/08 |
Claims
1. A method of operating a node of a first Radio Access Network
(RAN) of a first Radio Access Technology (RAT), the method
comprising: receiving an access attempt at the node from a user
device, wherein the access attempt includes a user device
identifier associated with a second Radio Access Network (RAN) of a
second Radio Access Technology different than the first Radio
Access Technology; transmitting a query from the node to the second
Radio Access Network, wherein the query includes an identification
of the user device based on the user device identifier received
from the user device; and after transmitting the query, providing a
communication service for the user device through the node of the
first Radio Access Network.
2. The method of claim 1 wherein the communication service
comprises a communication server previously provided to the user
device through the second Radio Access Network.
3. The method of claim 1 wherein the first Radio Access Technology
comprises an IEEE 802.11 compliant RAT, and wherein the second
Radio Access Technology comprises a GSM (Global System for Mobile
Communications) compliant RAT, a UMTS (Universal Mobile
Telecommunications System) compliant RAT, an FOMA (Freedom of
Mobile Multimedia Access) compliant RAT, an LTE (Long Term
Evolution) compliant RAT, a D-AMPS (Digital Advanced Mobile Phone
System) compliant RAT, and/or a CDMA (Code Division Multiple
Access) 2000 compliant RAT.
4. The method of claim 1 wherein the user device identifier
comprises a temporary identifier assigned by the second Radio
Access Network.
5. The method of claim 1 wherein the user device identifier
comprises an S-TMSI, P-TMSI, and/or EAP-SIM/AKA fast authentication
NAI.
6. The method of claim 1 wherein the user device identifier
comprises an International Mobile Subscriber Identity (IMSI).
7. The method of claim 1 wherein the query includes the user device
identifier received from the user device and associated with the
second Radio Access Network.
8. The method of claim 1 wherein the node comprises an IEEE 802.11
compliant node, and wherein the second Radio Access Technology
comprises a GSM (Global System for Mobile Communications) compliant
RAT, a UMTS (Universal Mobile Telecommunications System) compliant
RAT, an FOMA (Freedom of Mobile Multimedia Access) compliant RAT,
an LTE (Long Term Evolution) compliant RAT, a D-AMPS (Digital
Advanced Mobile Phone System) compliant RAT, and/or a CDMA (Code
Division Multiple Access) 2000 compliant RAT.
9. A node of a first Radio Access Network (RAN) of a first Radio
Access Technology (RAT), the node comprising: a processor
configured to, receive an access attempt from a user device,
wherein the access attempt includes a user device identifier
associated with a second Radio Access Network (RAN) of a second
Radio Access Technology different than the first Radio Access
Technology; transmit a query to the second Radio Access Network,
wherein the query includes an identification of the user device
based on the user device identifier received from the user device;
and provide a communication service for the user device through the
node of the first Radio Access Network after transmitting the
query.
10. A method of operating a node for use with a first access
network arranged to operate according to a first Radio Access
Technology capable of providing a communication service over a
first communication path to a user device through the first access
network and a second access network arranged to operate according
to a second Radio Access Technology capable of providing the
communication service over a second communication path to the user
device through the second access network, wherein the user device
is connectable to said first access network and to said second
access network and wherein the first and second Radio Access
Technologies are different, the method comprising: obtaining a user
device identifier identifying the user device when the user device
is seeking access to the second access network, wherein the user
device identifier is associated with first first access network,
wherein the user device identifier is provided by the user device;
obtaining information about a context of the user device in the
first access network based on the user device identifier;
generating an access selection decision for the access sought by
the user device to the second access network based on the provided
context information; and causing the access selection decision to
be executed.
11. The method of claim 10 wherein the user device identifier
comprises a temporary identifier assigned by the second Radio
Access Network.
12. The method of claim 11 wherein obtaining information comprises
obtaining a permanent identifier for the user device using the
temporary identifier and obtaining information about the context
using the permanent identifier.
13. The method of claim 11 wherein the temporary identifier is
provided from the user device through the second access
network.
14. The method of claim 10 wherein the identifier comprises an
S-TMSI, P-TMSI, and/or EAP-SIM/AKA fast authentication NAI.
15. The method of claim 10 wherein the user device identifier
comprises an International Mobile Subscriber Identity (IMSI).
16. The method of claim 10 wherein generating the access selection
decision includes connecting the user device to the second access
network including, identifying the communication service provided
initially to the user device through the first access network,
analyzing the provided context information of the user device, and
selecting the second access network to provide the communication
service to the user device based on the provided context
information of the user device, wherein causing the access
selection decision to be executed comprises providing the
communication service through the second access network.
17. The method of claim 10 wherein generating the access selection
decision comprises maintaining connection for the user device with
the first access network including, identifying the communication
service provided initially to the user device through the first
access network, analyzing the provided context information of the
user device, and selecting the first access network to provide the
communication service to the user device based on the provided
context information of the user device, wherein causing the access
selection decision to be executed comprises continuing to provide
the communication service through the first access network.
18. The method of claim 10 wherein generating the access selection
decision comprises mapping a first communication service of the
user device to the first access network and a second communication
service of the user device to the second access network including,
identifying the first communication service and the second
communication service provided initially to the user device through
the first access network, analyzing the provided context
information of the user device, selecting the first access network
to provide the first communication service to the user device based
on the provided context information of the user device, and
selecting the second access network to provide the second
communication service to the user device based on the provided
context information of the user device, wherein executing the
access selection decision comprises providing the first
communication service through the first access network and
providing the second communication service through the second
access network.
19. The method of claim 10 wherein the first Radio Access
Technology comprises a GSM (Global System for Mobile
Communications) compliant RAT, a UMTS (Universal Mobile
Telecommunications System) compliant RAT, an FOMA (Freedom of
Mobile Multimedia Access) compliant RAT, an LTE (Long Term
Evolution) compliant RAT, a D-AMPS (Digital Advanced Mobile Phone
System) compliant RAT, and/or a CDMA (Code Division Multiple
Access) 2000 compliant RAT, and wherein the second Radio Access
Technology comprises an IEEE 802.11 compliant RAT.
20. A node for use with a first access network arranged to operate
according to a first Radio Access Technology capable of providing a
communication service over a first communication path to a user
device through the first access network and a second access network
arranged to operate according to a second Radio Access Technology
capable of providing the communication service over a second
communication path to the user device through the second access
network, wherein the user device is connectable to said first
access network and to said second access network and wherein the
first and second Radio Access Technologies are different, the node
comprising: a processor configured to, obtain a user device
identifier identifying the user device when the user device is
seeking access to the second access network, wherein the user
device identifier is associated with first access network, wherein
the user device identifier is provided by the user device; obtain
information about a context of the user device in the first access
network based on the user device identifier; generate an access
selection decision for the access sought by the user device to the
second access network based on the provided context information;
and cause the access selection decision to be executed.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. National Stage
application Ser. No. 13/697,767 filed Nov. 13, 2012, which is a 35
U.S.C. .sctn.371 early national stage application of PCT
International Application No. PCT/SE2012/051007, filed on 24 Sep.
2012, which claims priority to U.S. Provisional Application No.
61/644,040, filed on 8 May 2012. The disclosures of the above
referenced applications are hereby incorporated herein in their
entireties by reference.
TECHNICAL FIELD
[0002] The present invention generally relates to mobile
communication. More particularly, the invention relates to a radio
communication system comprising a first access network arranged to
operate according to a first Radio Access Technology, a second
access network arranged to operate according to a second Radio
Access Technology, and a user device which is connectable to the
first access network and to the second access network. The
invention also relates to a method and an arrangement for use in a
radio communication system as referred to above, and to an
associated computer readable storage medium.
BACKGROUND
[0003] Different Radio Access Technologies (RAT:s) are available in
the modern world of mobile communication, allowing a user of a user
device such as a mobile terminal (User Equipment (UE)) to access
communication services like voice calls, Internet browsing, video
calls, file transmissions, audio/video streaming, electronic
messaging and e-commerce. Radio Access Technologies can be divided
into different categories.
[0004] A first and probably most widely spread category includes
RATs suitable for use in mobile or cellular telecommunications
systems like GSM (Global System for Mobile Communications), UMTS
(Universal Mobile Telecommunications System), FOMA (Freedom of
Mobile Multimedia Access), EPS (Evolved Packet System), D-AMPS
(Digital-Advanced Mobile Phone Service), CDMA2000 (Code Division
Multiple Access 2000) or WiMAX (Worldwide Interoperability for
Microwave Access). Common examples of RATs in this first category
are 3GPP (3rd Generation Partnership Project) GPRS/EDGE (General
Packet Radio Service/Enhanced Data rates for Global Evolution),
3GPP WCDMA/HSPA (Wideband Code Division Multiple Access/High-Speed
Packet Access), 3GPP LTE/E-UTRAN (Long-Term Evolution/Evolved
Universal Terrestrial Radio Access Network), and TD-SCDMA (Time
Division Synchronous Code Division Multiple Access).
[0005] A second category includes RATs which are suitable for use
in short-range wireless communication networks, such as Wi-Fi or
WLAN (Wireless Local Area Network). One example of a RAT in this
second category is the IEEE 802.11 family of wireless standards.
Other examples include Bluetooth and NFC (Near-Field
Communication).
[0006] Most user devices are nowadays enabled for use with more
than one RAT, such as one or more RATs selected from the first
category, as well as one or more RATs selected from the second
category. A mobile terminal, from now on referred to as User
Equipment or UE, enabled both for cellular access (e.g. 3GPP
LTE/E-UTRAN and/or WCDMA/HSPA for use in EPS and/or UMTS) and for
Wi-Fi access, will be used herein as an example of such a
multi-RAT-enabled user device.
[0007] Because of the inherent differences in architecture and
operation between mobile telecommunications networks on the one
hand and Wi-Fi networks on the other hand, in many existing setups
there has not been any integration between the two. Allowing two
such networks to co-exist in parallel but "hidden" from each other
is fully acceptable, but not optimal from resource utilization,
load distribution and user experience perspectives. Therefore,
certain integration attempts have been made, as will now be
described in some greater detail, however only for background
purposes.
[0008] Introduction
[0009] Operators of mobile telecommunications networks are today
mainly using Wi-Fi to offload traffic from the mobile networks, but
the opportunity to improve end-user experience regarding
performance is also becoming more important. The current Wi-Fi
deployments are mainly totally separate from mobile networks, and
are to be seen as non-integrated. The usage of Wi-Fi is mainly
driven due to the free and wide unlicensed spectrum, and the
increased availability of Wi-Fi in mobile terminals like
smartphones and tablets. The end-users are also becoming more and
more at ease with using Wi-Fi for example at offices and homes.
[0010] The different business segments for Wi-Fi regarding
integration possibilities can be divided into mobile operator
hosted/controlled versus third-party hosted/-controlled Wi-Fi APs
(Access Points). Here, "third-party" is seen as anything else than
a mobile operator, and that the third-party is not totally
"trusted" by the mobile operator. A third-party could be for
example a Wi-Fi operator or an end-user himself/-herself. In both
segments there exist public/hotspot, enterprise and residential
deployments.
[0011] Different Types of Wi-Fi Integration to Mobile Networks
[0012] Wi-Fi integration towards the mobile core network is
emerging as a good way to improve the end-user experience further.
These solutions consist mainly of the following components: common
authentication between 3GPP and Wi-Fi, and integration of Wi-Fi
user plane traffic to the mobile core network. The common
authentication is based on automatic (U)SIM-based ((Universal)
Subscriber Identity Module) authentication in both access types.
The Wi-Fi user plane integration gives the mobile operator an
opportunity to provide the same services, like parental control and
subscription-based payment methods, for the end-users both when
connected via 3GPP and when connected via Wi-Fi. Different
solutions are standardized in 3GPP. Overlay solutions (S2b, S2c)
have been specified since 3GPP Release 8, while integration
solutions (S2a) are currently work-in-progress (S2a, S2b, S2c
indicating the 3GPP interface/reference point names towards the
PDN-GW). These solutions are specified in 3GPP TS 23.402 (current
version=11.3.0), which can be obtained from the website of the 3rd
Generation Partnership Project at http://www.3gpp.com/.
[0013] Wi-Fi integration into radio access network (RAN) is also
emerging as an interesting study object. This has basically two
different possible levels that could be implemented either
separately or together. A first level of integration is to combine
both 3GPP and Wi-Fi in the small pico base stations to gain access
to the Wi-Fi sites with 3GPP technology, and vice versa. A second
level of integration is to integrate the Wi-Fi access tighter into
the RAN by introducing enhanced network controlled traffic steering
between 3GPP and Wi-Fi based on knowledge about the total situation
on the different accesses. The driver for this second level of
integration could be to avoid potential issues with UE (User
Equipment) controlled Wi-Fi selection, such as selecting Wi-Fi when
the Wi-Fi connection is bad or when the UE is moving, thus giving
better end-user performance and better utilization of the combined
Wi-Fi and cellular radio network resources.
[0014] FIG. 1 illustrates an existing network architecture for
integration of a mobile telecommunications system 110 in the form
of an EPS system, and a Wi-Fi access network 120. As is well known,
EPS was introduced in 3GPP Release 8 and Release 9. For detailed
information about EPS, reference is made to 3GPP TS 23.401 (current
version=11.2.0). The mobile telecommunications (EPS) system 110
comprises a radio access network 112 known as E-UTRAN (Evolved
Universal Terrestrial Radio Access Network) and a core network 114
known as EPC (Evolved Packet Core). The E-UTRAN has a combined base
station and radio network controller known as eNodeB. The EPC has
units known as MME (Mobility Management Entity) and a Serving GW
(Gateway). As is seen in FIG. 1, the eNodeB is connected via the S1
interfaces, S1-MME and S1-U to the MME and Serving GW,
respectively. FIG. 1 also shows how the Wi-Fi access network 120 is
connected to the PDN-GW via the S2a interface and to the 3GPP AAA
Server via the STa interface. The shown Wi-Fi access network is
just an example deployment and contains a Wi-Fi Access Point (AP),
a Wi-Fi Access Controller (AC) and a Broadband Network Gateway
(BNG).
[0015] Background to Hotspot 2.0
[0016] Different standards organizations have started to recognize
the needs for an enhanced user experience for Wi-Fi access, this
process being driven by 3GPP operators. An example of this is the
Wi-Fi Alliance with the Hotspot 2.0 (HS2.0) initiative, now
officially called PassPoint. For detailed information about Hotspot
2.0, reference is made to Wi-Fi Alliance Hotspot 2.0 (Release 1) TS
Version 1.0.0, which can be obtained from the website of the Wi-Fi
Alliance at http://www.wi-fi.org/. HS2.0 is primarily geared
towards Wi-Fi networks. HS2.0 builds on IEEE 802.11u, and adds
requirements on authentication mechanisms and auto-provisioning
support. For detailed information about IEEE 802.11u, reference is
made to IEEE 802.11u-2011, Amendment 9: Interworking with External
Networks, which can be obtained from the website
http://standards.ieee.org.
[0017] The momentum of Hotspot 2.0 is due to its roaming support,
its mandatory security requirements and for the level of control it
provides over the terminal for network discovery and selection.
Even if the current release of HS2.0 is not geared towards 3GPP
interworking, 3GPP operators are trying to introduce additional
traffic steering capabilities, leveraging HS2.0 802.11u mechanisms.
Because of the high interest of 3GPP operators, there will be a
second release of HS2.0 focusing on 3GPP interworking
requirements.
[0018] The HS2.0 contains the following procedures:
[0019] 1 Discovery: Where the terminal discovers a Wi-Fi network,
and probes it for HS2.0 support, using 802.11u and HS 2.0
extensions.
[0020] 2 Registration is performed by the terminal towards the
Wi-Fi Hot-spot network if there is no valid subscription for that
network.
[0021] 3 Provisioning: Policy related to the created account is
pushed towards the terminal. This only takes place when a
registration takes place.
[0022] 4 Access: Cover the requirements and procedures to associate
with a HS2.0 Wi-Fi network.
[0023] Background to Access Network Discovery and Selection
Function
[0024] The Access Network Discovery and Selection Function (ANDFS)
is an entity defined by 3GPP for providing access discovery
information as well as mobility and routing policies to the UE. The
information and policies provided by the ANDSF may be subscriber
specific.
[0025] Access Discovery Information is used to provide access
discovery information to the UE, which can assist the UE to
discover available (3GPP and) non-3GPP access networks without the
burden of continuous background scanning.
[0026] Inter-System Mobility Policies (ISMP) are policies which
guide the UE to select the most preferable 3GPP or non-3GPP access.
The ISMP are used for UEs that access a single access (3GPP or
Wi-Fi) at a time,
[0027] Inter-System Routing Policies (ISRP) are policies which
guide the UE to select over which access a certain type of traffic
or a certain APN shall be routed. The ISRP are used for UEs that
access both 3GPP and Wi-Fi simultaneously.
[0028] Background to Permanent UE Identifiers
[0029] The different permanent UE identifiers are defined in 3GPP
TS 23.003 (current version=11.2.0). The definition of International
Mobile Subscriber Identity (IMSI) is shown in FIG. 2. As seen in
this drawing, IMSI is composed of three parts:
[0030] 1. A Mobile Country Code (MCC) consisting of three digits.
The MCC uniquely identifies the country of the mobile
subscriber/subscription of the UE.
[0031] 2. A Mobile Network Code (MNC) consisting of two or three
digits. The MNC identifies the home PLMN (Public Land Mobile
Network) of the mobile subscriber/subscription. The length of the
MNC (two or three digits) depends on the value of the MCC.
[0032] 3. Mobile Subscriber Identification Number (MSIN)
identifying the mobile subscriber within a PLMN.
[0033] The National Mobile Subscriber Identity (NMSI) consists of
the Mobile Network Code (MNC) and the Mobile Subscriber
Identification Number (MSIN).
[0034] The International Mobile station Equipment Identity and
Software Version number (IMEISV), the International Mobile station
Equipment Identity (IMEI) and the MS international PSTN/ISDN number
(MSISDN) are also defined in 3GPP TS 23.003 but are not further
described herein.
[0035] In the EPS (110, FIG. 1), the permanent UE identities are
only known in the EPC 114, whereas the E-UTRAN 112 is only aware of
temporary UE identities. An example of this is the Globally Unique
Temporary UE Identity (GUTI) that uniquely identifies the MME which
allocated the GUTI and also identifies the UE within the MME that
allocated the GUTI. Another example used for paging purposes is the
S-TMSI. GUTI and S-TMSI are also defined in the aforementioned 3GPP
TS 23.003. The GUTI is allocated to the UE during an Attach
procedure as defined in the aforementioned 3GPP TS 23.401 (also see
FIGS. 3A and 3B), and the serving MME holds the association between
the GUTI and the UE permanent identifier(s).
[0036] When the UE accesses a Wi-Fi network, it can be
authenticated using EAP-SIM (Extensible Authentication
Protocol-SIM) and EAP-AKA (Extensible Authentication
Protocol-Authentication and Key Agreement) protocols. In these
cases, the UE can be identified by either the full authentication
Network Access Identifier (NAI) or by the fast re-authentication
NAI. The full authentication NAI contains the IMSI of the UE, and
the fast re-authentication NAI is similar to the temporary
identities used in LTE access in the sense that it is the 3GPP AAA
Server that knows the relation between the fast re-authentication
NAI and the full authentication NAI.
[0037] Overview 3GPP Attach Procedure
[0038] FIGS. 3A and 3B shows an overview of the attach procedure
used in for instance the E-UTRAN 112 of FIG. 1. The attach
procedure is described in detail in 3GPP TS 23.401. During this
attach procedure, the UE is authenticated to the network in a step
5a, using credentials stored on the (U)SIM ((Universal) Subscriber
Identity Module) in the UE. At initial attach, the UE will use the
IMSI as an identifier of the UE subscription (and (U)SIM). During
the attach to the network, the UE might be assigned other shorter
temporary identifiers such as S-TMSI, P-TMSI, URNTI, etc. The
MME/SGSN in the 3GPP Core Network (CN) will be aware of the IMSI
associated and the mapping to temporary identifiers when the UE has
an active context in the network.
[0039] Overview of Wi-Fi Attach Procedure with EAP-SIM/AKA
Authentication
[0040] FIG. 4 shows an example procedure for a Wi-Fi-enabled UE
connecting to a Wi-Fi network, such as access network 120 in FIG.
1, with a Wi-Fi Access Controller (AC). Other procedures may also
be used depending on implementation in the UE and network. The EAP
signalling is in this procedure used to authenticate the UE towards
the network. The UE uses IMSI or some other certificate to identify
itself towards the network.
[0041] Some Problems with Existing Solutions
[0042] The current methods for integration of Wi-Fi into a 3GPP
network described above do not offer good support for
network-controlled Wi-Fi/3GPP access selection and service mapping,
taking into consideration radio access related input parameters
such as UE mobility, 3GPP/Wi-Fi cell and network load, radio link
performance, etc.
[0043] In order to achieve this functionality, it is required to
link (connect, associate) the UE context in the 3GPP radio access
network (RAN)--which holds information about radio performance, UE
mobility, etc. on the 3GPP side--with the UE context in the Wi-Fi
network. This can then enable a network entity to take decisions
whether the UE should access the Wi-Fi network or not, depending on
if the UE is stationary, and/or has a good connection to the Wi-Fi
AP (Access Point), etc. The decision can then be signaled to the UE
or executed internally in the 3GPP/Wi-Fi network (for instance to
control UE admission to Wi-Fi).
[0044] Although mechanisms have been introduced for allowing the UE
to perform authentication towards the Wi-Fi network using (U)SIM
credentials and identities (IMSI), there is currently no mechanism
available for connecting the UE RAN context in the 3GPP RAN with
the UE Wi-Fi access context.
[0045] This means that with existing solutions, there is no node in
the access network that can identify a single UE to be the same UE
when it is active in Wi-Fi and 3GPP, respectively--even if it is
handled by the same physical base station (e.g. eNodeB, WiFi
AC).
SUMMARY
[0046] It is accordingly an object of the invention to eliminate or
alleviate at least some of the problems referred to above.
[0047] The present inventors have realized, after inventive and
insightful reasoning, that it will be beneficial to introduce
additional functionality serving to: [0048] Locate the UE RAN
context in the other RAT (Wi-Fi, 3GPP RAN) based on a permanent or
temporary identifier of the UE. [0049] Convey RAN related
parameters between the RAN entities serving the UE and thus
enabling access network selection or service mapping decisions for
the UE to be taken in the network. [0050] Convey the access network
selection or service mapping decisions to RAN nodes (Wi-Fi or 3GPP
RAN).
[0051] A basic concept may also include: [0052] Conveying the
access network selection or service mapping decisions to the UE
(e.g. in the form of access selection commands or access selection
policies). [0053] Assigning temporary identities to the UE while
connected in one RAT, which the UE subsequently uses to identify
itself in the other RAT.
[0054] The concept can be used together with existing methods for
integrating UE Wi-Fi traffic in 3GPP networks (e.g. S2a method as
seen in FIG. 1 and S2b and S2c methods not shown in FIG. 1) as well
as existing authentication methods such as (U)SIM-based (e.g.
EAP-SIM or EAP-AKA, as described above), or alternatively
certificate-based (EAP-TLS), etc. For a further description of
EAP-TLS (Extensible Authentication Protocol-Transport Layer
Security), reference is made to the open standard RFC 5216 by IETF
(Internet Engineering Task Force), which is available at
http://www.rfc-editor.org/rfc/rfc5216.txt.
[0055] On a high level, such a basic concept may form the basis for
network-controlled access selection or service mapping as
follows:
[0056] 1. When the UE is connected to one access network (e.g.
3GPP) (Access A) and finds a suitable cell of the other access
network (e.g. Wi-Fi) (Access B), it will, depending on
implementation rules, initiate access procedure towards Access
B.
[0057] 2. During this procedure the UE will identify itself in the
network using an identifier known in Access A, or that can be
translated by Access B to an identifier known in Access A.
[0058] 3. This identifier will be used by a network node to find
the RAN context in the Access A.
[0059] 4. Once the RAN context has been located the network can
perform internal signaling between the RAN nodes of the different
access (Access A and Access B) to convey radio related parameters
which can be used for access selection (e.g. moving a UE towards
the new access (Access B), leaving the old access (Access A))
and/or service mapping (e.g. mapping some services on the new
access (Access B), keeping ongoing UE connection to the old access
(Access A)).
[0060] 5. Once an access selection/service mapping decision has
been performed, the network entity responsible for the decisions
will convey this information to the UE or to some other network
entity which has control of the UE access selection or service
mapping.
[0061] One aspect of the present invention can therefore be
summarized as a radio communication system comprising a first
access network arranged to operate according to a first Radio
Access Technology, a second access network arranged to operate
according to a second Radio Access Technology, and a user device
which is connectable to said first access network and to said
second access network. The system further comprises:
[0062] an authentication node arranged to identify said user
device, when seeking access to said second access network, through
a user device identifier for said user device, wherein said user
device identifier is associated with said first access network;
[0063] a query node arranged to provide information about a context
of said user device in said first access network based on said user
device identifier; and
[0064] an access selection node arranged to generate an access
selection decision for the access sought by the user device to the
second access network based on the provided context
information.
[0065] The system is arranged to cause said access selection
decision to be executed.
[0066] In one or more embodiments, the authentication node may be
arranged to identify said user device based on a user identifier
provided by the user device. This identifier may be an
International Mobile Subscriber Identity (IMSI).
[0067] In one or more embodiments, the identifier is a temporary
identifier assigned to said user device in said first access
network, wherein said authentication node is arranged to use the
temporary identifier for retrieving a permanent identifier of said
user device from a network resource in or via said first access
network. The temporary identifier may be, for instance, a Packet
Temporary Mobile Subscriber Identity (P-TMSI) or Shortened
Temporary Mobile Subscriber Identity (S-IMSI).
[0068] The feature "said user device identifier is associated with
said first access network" is to be construed broadly to comprise,
without limitations, cases where the user device identifier is
directly associated with or known to the first access network (for
instance a temporary identifier like P-TMSI), as well as cases
where the user device identifier is indirectly associated with the
first access network (for instance in the form of a mapping between
a temporary identifier like P-TMSI--which is directly known to the
first access network--and a permanent identifier like IMSI, wherein
the mapping is held by a network node somewhere in the radio
communication system, for instance in a node in a core network
coupled to the first access network).
[0069] In one or more embodiments, the context information provided
by said query node about said user device includes a current
location of said user device in said first access network.
[0070] Moreover, said query node may be further configured for
signaling with said first access network and/or said second access
network to provide parameters to said access selection node,
wherein said access selection node is configured to generate said
access selection decision based on said parameters.
[0071] These parameters may typically relate to one or more of the
following:
[0072] mobility data about said user device,
[0073] work load for a current access point of said user device in
said first access network,
[0074] work load for an access point in said second access network
to which said user device seeks access,
[0075] transport network load in either of said first or second
access networks,
[0076] radio link performance for said user equipment in said first
access network,
[0077] Radio Access Technology-specific limitations in either of
said first or second access networks,
[0078] ongoing services used by said user device,
[0079] capabilities of said user device for said first or second
Radio Access Technologies, and
[0080] a subscription profile of an end-user associated with said
user device.
[0081] In one or more embodiments, the access selection decision
involves at least one of the following:
[0082] connecting said user device to said second access
network,
[0083] disconnecting said user device from said first access
network,
[0084] mapping a first service of said user device to said first
access network and a second service of said user device to said
second access network, and
[0085] maintaining connection for said user device with said first
access network. Hence, typical implications of the term "access
selection decision" are that the user device shall be connected or
disconnected to any of the first and second access networks, that
the user device shall maintain a current connection, and/or that
services utilized by the user device shall be split between the
first and second access networks.
[0086] In one or more embodiments, the access selection node is
further configured to cause transmission of said access selection
decision to said user device for execution of said access selection
decision.
[0087] Alternatively or additionally, the access selection node may
be further configured to cause transmission of said access
selection decision to said first access network and/or to said
second access network for execution of said access selection
decision.
[0088] The first access network may be part of a mobile
telecommunication system compliant with, for instance, GSM, UMTS,
FOMA, EPS, D-AMPS or CDMA2000. Hence, the first access network may
for instance be capable of radio communication in accordance with
GPRS/EDGE, WCDMA/HSPA, LTE/E-UTRAN, or any combination thereof, or
alternatively TD-SCDMA. Other existing and future mobile
telecommunication systems and radio communication technologies are
however also feasible.
[0089] The second access network may be a short-range wireless
communication network compliant with, for instance, IEEE 802.11
(Wi-Fi or WLAN). Alternatively, the second access network may be of
any of the types referred to above for the first access network.
Other existing and future technologies are however also feasible,
as was referred to in the background section of this document.
[0090] The authentication node, query node and access selection
node are to be seen as functional elements rather than structural.
Hence, in an implementation of the system, the functionalities of
these three nodes may be split between and/or performed in a
distributed cooperative manner by other, existing nodes in the
first and second access networks, or in the user device. Some
examples of this will be found in the detailed description section
of this document. Alternatively, some or all of the functionalities
of these three nodes may be performed by separate hardware
dedicated for this purpose, such as appropriately configured
computer equipment.
[0091] Another aspect of the present invention can be summarized as
a method for use in a radio communication system of the type which
comprises a first access network arranged to operate according to a
first Radio Access Technology, a second access network arranged to
operate according to a second Radio Access Technology, and a user
device which is connectable to said first access network and to
said second access network. The method comprises:
[0092] identifying said user device, when seeking access to said
second access network, through a user device identifier for said
user device, wherein said user device identifier is associated with
said first access network;
[0093] providing information about a context of said user device in
said first access network based on said user device identifier;
[0094] generating an access selection decision for the access
sought by the user device to the second access network based on the
provided context information; and
[0095] causing execution of said access selection decision.
[0096] In one or more embodiments, the user device is identified
based on a user identifier provided by the user device. This
identifier may be an International Mobile Subscriber Identity
(IMSI).
[0097] In one or more embodiments, the identifier is a temporary
identifier assigned to said user device in said first access
network, and wherein the identifying of said user device further
comprises using the temporary identifier for retrieving a permanent
identifier of said user device from a network resource in or via
said first access network.
[0098] In one or more embodiments, the context information provided
by said query node about said user device includes a current
location of said user device in said first access network.
[0099] Moreover, the method may further comprise:
[0100] signaling with said first access network and/or said second
access network to provide parameters; and
[0101] generating said access selection decision based on the
provided parameters.
[0102] These parameters may typically relate to one or more of the
following:
[0103] mobility data about said user device,
[0104] work load for a current access point of said user device in
said first access network,
[0105] work load for an access point in said second access network
to which said user device seeks access,
[0106] transport network load in either of said first or second
access networks,
[0107] radio link performance for said user equipment in said first
access network,
[0108] Radio Access Technology-specific limitations in either of
said first or second access networks,
[0109] ongoing services used by said user device,
[0110] capabilities of said user device for said first or second
Radio Access Technologies, and
[0111] a subscription profile of an end-user associated with said
user device.
[0112] In one or more embodiments, the access selection decision
involves at least one of the following:
[0113] connecting said user device to said second access
network,
[0114] disconnecting said user device from said first access
network,
[0115] mapping a first service of said user device to said first
access network and a second service of said user device to said
second access network, and
[0116] maintaining connection for said user device with said first
access network.
[0117] In one or more embodiments, the generated access selection
decision may be transmitted to said user device for execution of
the access selection decision.
[0118] Alternatively or additionally, the generated access
selection decision may be transmitted to said first access network
and/or to said second access network for execution of the access
selection decision.
[0119] Yet another aspect of the present invention can be
summarized as a computer readable storage medium encoded with
instructions that, when loaded and executed by a processor, causes
performance of the method referred to above.
[0120] Still another aspect of the present invention can be
summarized as an arrangement for use in a radio communication
system comprising a first access network arranged to operate
according to a first Radio Access Technology and a second access
network arranged to operate according to a second Radio Access
Technology, wherein said arrangement comprises:
[0121] means for identifying a user device, when seeking access to
said second access network, through a user device identifier for
said user device, wherein said user device identifier is associated
with said first access network;
[0122] means for providing information about a context of said user
device in said first access network based on said user device
identifier; and
[0123] means for generating an access selection decision for the
access sought by the user device to the second access network based
on the provided context information.
[0124] In embodiments of this arrangement, the means for
identifying a user device may be implemented by the aforementioned
authentication node in the radio communication system aspect of the
invention. Correspondingly, in embodiments of this arrangement, the
means for providing information about a context of said user device
may be implemented by the aforementioned query node in the radio
communication system aspect of the invention. Also, in embodiments
of this arrangement, the means for generating an access selection
decision may be implemented by the aforementioned access selection
node in the radio communication system aspect of the invention.
[0125] The arrangement may further comprise means for causing said
access selection decision to be executed in said radio
communication system.
[0126] In addition, the arrangement may further comprise means for
causing performance of any functional feature of the method aspect
referred to above.
[0127] For further objects, features and advantages of the
invention and/or its embodiments, reference is made to the
following detailed description, to the attached claims as well as
to the drawings.
[0128] Generally, all terms used in the claims are to be
interpreted according to their ordinary meaning in the technical
field, unless explicitly defined otherwise herein. All references
to "a/an/the [element, device, component, means, step, etc]" are to
be interpreted openly as referring to at least one instance of the
element, device, component, means, step, etc., unless explicitly
stated otherwise. The steps of any method disclosed herein do not
have to be performed in the exact order disclosed, unless
explicitly stated. It should be emphasized that the term
"comprises/comprising" when used in this specification is taken to
specify the presence of stated features, integers, steps, or
components, but does not preclude the presence or addition of one
or more other features, integers, steps, components, or groups
thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0129] Embodiments of the invention will be described in further
detail below with reference to the accompanying drawings.
[0130] FIG. 1 schematically illustrates an existing network
architecture for integration of a mobile telecommunications system
and a Wi-Fi access network.
[0131] FIG. 2 illustrates the definition of International Mobile
Subscriber Identity (IMSI).
[0132] FIGS. 3A and 3B show an overview of an attach procedure used
in for instance the radio access network of the mobile
telecommunications system shown in FIG. 1.
[0133] FIG. 4 shows an overview of an attach procedure used in for
instance the Wi-Fi access network shown in FIG. 1.
[0134] FIG. 5A schematically illustrates a high level functional
architecture of an embodiment of the present invention.
[0135] FIG. 5B is a flowchart diagram to illustrate the
functionality of an embodiment of the present invention.
[0136] FIG. 5C illustrates a computer readable storage medium
encoded with instructions that, when loaded and executed by a
processor, may cause performance of the functionality shown in FIG.
5B.
[0137] FIG. 6 is a schematic flowchart diagram of a procedure for
finding context information about a user device in a first access
network when seeking access to a second access network.
[0138] FIG. 7 is a schematic flowchart diagram of a procedure which
can be used when maintaining the context information about the user
device in the first access network.
[0139] FIG. 8 is a schematic flowchart diagram of a procedure for
transferring of parameters related to the first and second access
networks, for use when performing an access network selection
and/or service mapping decision for the user device seeking access
to the second access network.
[0140] FIG. 9 is a schematic block diagram of a user device which
is connectable to first and second access networks.
[0141] FIG. 10 is a schematic block diagram illustrating an
arrangement according to one aspect of the invention.
DETAILED DESCRIPTION
[0142] Embodiments of the invention will now be described with
reference to the accompanying drawings. The invention may, however,
be embodied in many different forms and should not be construed as
limited to the embodiments set forth herein; rather, these
embodiments are provided so that this disclosure will be thorough
and complete, and will fully convey the scope of the invention to
those skilled in the art. The terminology used in the detailed
description of the particular embodiments illustrated in the
accompanying drawings is not intended to be limiting of the
invention. In the drawings, like numbers refer to like
elements.
[0143] A high level functional architecture of an embodiment of the
present invention is shown in FIG. 5A. A corresponding
functionality is shown in FIG. 5B. As seen in FIG. 5A, a user
device 500 is connectable to a first access network 510, also
referred to as Access A. The user device 500 is also connectable to
a second access network 520, also referred to as Access B. The
first access network 510, Access A, is arranged to operate
according to a first Radio Access Technology, which in the
disclosed embodiments is either 3GPP WCDMA/HSPA or LTE/E-UTRAN, or
WCDMA/HSPA and LTE/E-UTRAN in combination. Correspondingly, the
second access network 520, Access B, is arranged to operate
according to a second Radio Access Technology, which in the
disclosed embodiment is WiFi. Thus, in the disclosed embodiments
the user device 500 is a user equipment, UE. An embodiment of such
a UE is illustrated in more detail as 900 in FIG. 9 and will be
described in more detail later. Other embodiments may be however be
based on other Radio Access Technologies for the first and second
access networks 510, 520, as has been referred to previously in
this document.
[0144] The architecture shown in FIG. 5A moreover comprises an
Authentication Node (AN) 530, one or more Query Nodes (QNs) 540 and
an Access Selection Node (ASN) 550. The illustration shows that for
example the QN 540 may be part of Access A or outside of Access A.
In a similar way, the AN 530 may be part of Access B or outside
Access B. When it comes to the ASN 550, it is shown in FIG. 5A as
being outside both Access A and B. Any other alternatives are also
possible, i.e. the ASN 550 may be part of Access A or Access B as
well. It is also possible that the ASN 550 is distributed, such
that its functionality is performed by or at more than one entity
in the system. Furthermore, it is also possible that the
communication between the AN 530 and the QN(s) 540 occurs via the
ASN 550, or that the communication occurs directly between these
functions.
[0145] As is seen in the flowchart in FIG. 5B, step 600, the
authentication node AN 530 is arranged to identify the UE 500 when
seeking access to the second access network 520, Access B, through
a user device identifier for the UE 500, wherein this user device
identifier is associated with the first access network 510, Access
A.
[0146] As is seen further in the flowchart in FIG. 5B, step 610,
the query node QN 540 is arranged to provide information about a
context of the UE 500 in the first access network 510, Access A,
based on the user device identifier.
[0147] Moreover, as is seen further in the flowchart in FIG. 5B,
step 620, the access selection node ASN 550 is arranged to generate
an access selection decision for the access sought by the UE 500 to
the second access network 520, Access B, based on the provided
context information.
[0148] Finally, as is seen further in the flowchart in FIG. 5B,
step 630, the system is arranged to cause the access selection
decision to be executed.
[0149] It is to be understood that FIG. 5A is a logical drawing
rather than a physical; hence the functions of the different
entities shown in FIG. 5A can be implemented in different physical
units in the system. For example, if Access A is 3GPP WCDMA/HSPA
and Access B is Wi-Fi, then the QN 540 could be communicating
towards a radio network controller (RNC) in Access A, or it may be
implemented as part of the RNC. In another example, if Access A is
3GPP LTE/E-UTRAN and Access B is Wi-Fi, then the QN 540 could be
communicating towards the eNodeB in the E-UTRAN 112 of FIG. 1, or
it may be implemented as part of the eNodeB. Correspondingly, the
AN 530 may be part of for example a Wi-Fi Access Controller
(AC)--such as the one shown in the Wi-Fi access network 120 of FIG.
1--or it may communicate with such a Wi-Fi AC. Also, in this case,
the ASN 550 could implemented as part of the Wi-Fi AC, the RNC or
as a stand-alone physical node.
[0150] The envisioned solution according to FIGS. 5A and 5B is a
target-based network-controlled solution, where the UE by itself
tries to perform access to the target access (Access B), which then
triggers the network to take an access selection or services
mapping decision.
[0151] It is to be noticed that this is distinctly different from
the existing inter-RAT handover mechanism within 3GPP, where the UE
sends a measurement report to the source RAT (over the source
radio), so that the source RAT can initiate handover (to a specific
target cell). In those types of existing solutions, there is no
need for the functionality of finding the RAT context in the source
RAT based on a UE identifier, since the handover decision is taken
in the source RAT prior to UE accessing the target RAT. The
envisioned solution according to FIGS. 5A and 5B moreover relies on
that the UE will not leave the source RAT until it has successfully
connected to the target RAT--which is different from existing
procedures. This makes it possible to use a mechanism in the target
RAT for controlling the UE access selection (i.e. by denying the UE
access in the target RAT, the UE will stay in the source RAT).
[0152] The advantage of such target-based solutions is that they do
not require any UE impacts (meaning that they can be applied to
existing UEs on the market). Target-based solutions in accordance
with the present invention can however still benefit from UE
impacts.
[0153] FIG. 5C shows a schematic view of a computer readable
storage medium 640 which may be used to accommodate instructions
for performing the functionality of the present invention, as is
generally outlined in FIG. 5B. In the embodiment shown in FIG. 5C,
the computer-readable medium 640 is a memory stick, such as a
Universal Serial Bus (USB) stick. The USB stick 640 comprises a
housing 643 having an interface, such as a connector 644, and a
memory chip 642. The memory chip 642 is a flash memory, i.e. a
non-volatile data storage that can be electrically erased and
re-programmed. The memory chip 642 is programmed with instructions
641 that when loaded (possibly via the connector 644) into a
processor will cause execution of the method.
[0154] The processor may be at least one CPU (Central Processing
Unit), DSP (Digital Signal Processor), FPGA (Field-Programmable
Gate Arrays), ASIC (Application Specific Integrated Circuit) or any
other electronic programmable logic device, or a combination of any
such devices, adapted for executing the instructions stored on the
aforementioned storage medium 640. Such a processor may act as a
controller in a node in the first or second access networks (Access
A, Access B). The instructions may be adapted for execution by
several processors, possibly located in different nodes in said
first and second networks, in a distributed cooperative manner, as
is mentioned is other parts of this document.
[0155] It should be noted that the USB stick 640 in FIG. 5C is
merely one example of a computer-readable storage medium. Other
examples may include compact discs, digital video discs, hard
drives or other memory technologies commonly used.
[0156] The general functionality according to FIGS. 5A and 5B above
will now be described in more detail in the following numbered
subsections:
[0157] 1. Identification of UE when accessing a new target network
(Access B)
[0158] 2. Finding the RAN context of the UE in a previous RAT
(Access A)
[0159] 3. Transferring of RAN related parameters and performing
access network selection/service mapping decision based on those
parameters
[0160] The following additions will also be discussed:
[0161] 4. Methods for conveying and/or executing access selection
and service mapping decisions
[0162] 5. Methods for using network assigned temporary identities
in order to make it less complex to find the UE context in the
previous RAT (Access A), as well as additional privacy or integrity
functionality (avoiding the use of permanent identifiers).
[0163] 1. Identification of the UE (FIG. 5B, Step 600)
Embodiments Based on IMSI
[0164] If the UE supports EAP-SIM or EAP-AKA based authentication
in Wi-Fi (i.e. Access B), it will (at least for initial attach)
identify itself to the Wi-Fi network (internally the Wi-Fi Access
Controller or some other node having the authenticator role), using
the IMSI ((U)SIM-related identifier). For details about attach
procedures used in Wi-Fi access networks, reference is made to the
previous description with respect to FIG. 4 above.
[0165] Similarly, when the UE performs access to 3GPP (i.e. Access
A), it will (at least for initial attach) also use the IMSI as an
identifier (towards the MME). For details about attach procedures
used in 3GPP networks, reference is made to the previous
description with respect to FIGS. 3A and 3B above.
[0166] This means that in a typical embodiment there will be a
network node (or function) identifying that a particular UE (as
given by the IMSI) is performing access to the target network
(Access B). This node will then perform a procedure to try to
locate the RAT context of the UE in the previous RAT (Access
A).
[0167] Embodiments based on other identifiers that can be
translated to IMSI by the network (e.g. P-TMSI, S-TMSI, temporary
EAP identifiers)
[0168] In case the UE has been previously connected to a particular
access network, it might have been assigned an access-specific
temporary identifier, such as 3GPP-defined S-TMSI or P-TMSI,
EAP-SIM/AKA fast re-authentication NAI, etc. In this case, the
network node responsible for the authentication needs to either
have stored the permanent UE identity (e.g. IMSI received from the
last time the UE was connected to the access network), or retrieve
the permanent identity from another node or network resource, such
as an AAA server or MME (FIG. 1) or Home Location Register (HLR).
In the latter case, the temporary identifier is used to find the
context in the other node.
[0169] In case the UE uses some non-(U)SIM-based mechanism to
identify itself, such as EAP-TLS/TTLS based on a stored certificate
in the UE, the network node responsible for the authentication in
the access network needs to also retrieve the IMSI in conjunction
with authentication procedure. The IMSI could in this case for
instance be stored in an AAA-server or HLR, which also contains
information about the certificate of the UE. During the
authentication procedure the IMSI can be passed on to the node in
the target access network responsible for the authentication of the
UE.
Embodiments Based on Temporary Identifiers Assigned by Previous RAT
(Access A)
[0170] Here, the source access network (Access A) will assign to
the UE an UE identity while the UE is in Access A. This identity
can be assigned using dedicated signaling, transferred in a secure
manner over the radio interface of Access A. The actual identity
could be made up of a random temporary identifier, such as 3GPP
S-TMSI, P-TMSI, or it could be an IP address which the UE also uses
for communication, or some specific bit-string. The identity can
also, in combination with UE-specific identity, also contain
information which is used for internal routing in the network (such
as, for instance, identity information regarding the relevant MME,
RNC, Wi-Fi AC, etc). Other possible combinations of identities are
also possible.
[0171] When the UE later performs access to the target access
network (Access B), it will transfer the assigned identity to the
target access network (Access B), which then can be used by Access
B to locate the UE context in the source access network (Access
A).
[0172] 2. Finding the RAN Context of the UE in a Previous RAT (FIG.
5B, Step 610)
[0173] Once the node responsible for authentication, i.e. the
Authentication Node (AN) 530 of the UE in the target RAT (Access B)
has determined the unique identifier (e.g. IMSI) of the UE seeking
the access (as described in subsection 1 above), it will initiate
procedure to locate the UE context in the previous RAT (Access A).
This procedure is achieved by querying a node or function, namely
the Query Node (QN) 540, which is aware of the UE location in the
previous RAT. This Query Node is able to map the unique identifier
to a UE RAN context located either in that node or in a separate
node. In case the UE RAN context is located in a separate node
(Previous RAT Node), the Query Node 540 will assist the
communication between the separate node and the Authentication Node
530, either by providing addressing information of the Previous RAT
Node to the Authentication Node 530, or by forwarding messages
between the Previous RAT Node and Authentication Node 530.
[0174] The Authentication Node 530 can query multiple Query Nodes
540 for a given UE. In case a Query Node 540 is not aware of the
location of the UE, it can either respond with a negative message
to the Authentication Node 530, or it can in turn query another
Query Node 540 which could know the location of the UE. In other
words, the Query Nodes 540 can be cascaded. This procedure can be
enhanced based on information in the Authentication Node 530 about
the location (e.g. geo position) of the access nodes (e.g. 3GPP
base stations, Wi-Fi APs) or UE, meaning that the Authentication
Node 530 can focus on querying Query Nodes 540 which are associated
with source RAT nodes which covers the same area as the target RAT
nodes (e.g. the 3GPP cells which have partially overlapping
coverage with the Wi-Fi cell that the UE is accessing).
[0175] The Query Node 540 can either be implemented together with
RAT specific functions such as RNCs, Wi-Fi access controllers,
MMEs, etc., or it can be a stand-alone node.
[0176] In the latter case it will receive signaling from the RAT
specific nodes to update the Query Node 540 about the location of
specific UEs. This signaling is described further below.
[0177] In the former case, i.e. when the Query Node 540 is
implemented together with RAT specific functions, this signaling to
update the location of specific UEs could be part of normal RAT
specific mobility signaling (e.g. handovers, path switch, cell
update). In addition, the Query Node 540 can also be implemented
together with the Authentication Node 530. FIG. 6 shows an example
of this case, where the RAN context of the UE is located in Access
A (the source RAT) when the UE is attempting to access Access B
(the target RAT).
[0178] Signalling Between RAT Specific Nodes and Query Nodes
[0179] In case the Query Nodes are implemented separately from the
RAT specific nodes handling the UE RAN context (including mobility
handling, etc.), the RAT specific node will perform signaling
towards the Query Nodes when the UE register in the RAT the first
time, and when the UE is moving in the RAT. In addition to this
signalling, the RAT nodes can also inform the Query Node about UE
specific information, such as UE capabilities, ongoing services, UE
mobility states etc.
[0180] The UE can be identified in this signaling by using a unique
identifier (e.g. IMSI) or a temporary identifier assigned while the
UE was in the source RAT (Access A). FIG. 7 shows an example of
this case. The RAT specific nodes Access A1 and A2 can be for
example RNCs, eNodeBs or MMEs, as described in other parts of this
document.
[0181] 3. Transferring of RAN Related Parameters and Performing
Access Network Selection or Service Mapping Decision Based on Those
Parameters (FIG. 5B, Steps 610 and 620)
[0182] In conjunction with the signaling to find the UE context in
the source RAT (Access A) as described above and with reference to
step 610 of FIG. 5B, it is possible to also transfer RAN related
information from the source and target RATs (Access A and Access B)
to the Access Selection Node, ASN, 550 responsible for performing
access selection, and/or service mapping, decisions. This ASN node
550 is responsible for deciding if the UE should be accepted in the
target access network (Access B) and/or if the UE should leave the
source access network (Access A) or not. Furthermore, the ASN 550
node can decide if a specific service of the UE should be mapped on
a specific access network among Access A or Access B.
[0183] The Access Selection Node 550 can base this decision upon
RAN related parameters provided by the source and target RATs, as
well as information provided from the UE. Possible parameters
include (but are not limited to) information about: [0184] UE
mobility (e.g. UE speed) [0185] Cell load in target or source cell
[0186] Transport network load [0187] Radio link performance (e.g.
Signal to Noise ratio, coding or modulation scheme used) [0188]
RAT-specific limitations (e.g. maximum bit rates, service
limitations) [0189] Ongoing UE services [0190] UE device
capabilities for the different RATs [0191] Subscription profile of
the end-user (e.g. different subscription classes
(gold/silver/bronze), pre-paid/post-paid, etc.
[0192] These parameters can be sent to the ASN 550 both from Access
A (source RAT) and from Access B (target RAT) in order to
facilitate access selection and/or service mapping decision by the
ASN 550 based on those parameters. The parameters can also be sent
from a node outside of the source and target RATs, such as for
instance by a node in a core network coupled to any of the RATs.
For instance, the relevant information for the parameters may be
held by an MME in the core network 114 coupled to the RAT 112 as
seen in FIG. 1.
[0193] The signaling to transfer these parameters to the ASN 550
can be performed as separate signaling or piggybacked on the
messages used to locate the RAN context.
[0194] The Access Selection Node 550 can be implemented together
with the Authentication Node 530 and/or Query Node(s) 540, or as a
stand-alone entity. The Access Selection Node 550 can even be
implemented in the UE based on information provided by the network
(e.g. from source/target RAT). In case the Access Selection Node
550 is implemented in the network, it can be implemented together
with existing nodes e.g. MMEs, RNCs, Wi-Fi AP, Wi-Fi AC, eNodeB,
etc.
[0195] FIG. 8 shows an example of this case. This example is based
on that the signalling from the AN 530 towards the QN(s) 540 is
separate from the signalling towards the ASN 550. Steps 1 to 5 are
the same as in FIG. 6, and the new parts are shown as steps 6 and
7.
[0196] 4. Methods for Conveying and/or Executing Access Selection
and/or Service Mapping Decisions (FIG. 5B, Step 630)
[0197] Based on the information made available according to the
preceding subsections as described above, the ASN 550 takes an
access selection and/or service mapping decision for the access
sought by the UE to the second access network (Access B, target
RAT). The decision taken needs to be conveyed to different parts of
the network depending on the decision taken, in accordance with the
following: [0198] If the decision taken is to reject the UE's
access attempt to Access B, then the ASN 550 informs the AN 530 in
Access B about the decision. Thus, the AN 530 performs the needed
signalling towards the UE to indicate the rejected access attempt.
[0199] If the decision taken is to accept the UE's access attempt
to Access B, then the ASN 550 informs the AN 530 in Access B about
the decision. Thus, the AN 530 performs the needed signalling
towards the UE to indicate the accepted access attempt. [0200] If
the decision taken is a service mapping decision (i.e. the UE is
allowed to access both Access A and Access B simultaneously), the
ASN 550 needs to inform both the network side and the UE about the
decision. The UE needs this information to be able to perform the
decided service mapping in the uplink direction. At the network
side, there needs to exist a common point in the network that
performs the service mapping in the downlink direction towards
Accesses A and B. [0201] If the functionality of the ASN 550 is
implemented in the UE and the decision is to not continue with the
access attempt to Access B, the UE will stop performing access to
Access B. This could include sending some signaling messages to
Access B or A.
[0202] FIG. 9 illustrates a user device 900 which is connectable to
first and second access networks, Access A and Access B. The user
device 900 may implement the UE 500 according to the preceding
drawings and descriptions.
[0203] The user device 900 has a controller 950 which has the
overall responsibility for controlling the operation of the user
device 900. In the disclosed embodiment, the controller 950 is a
central processing unit (CPU), but it can alternatively be a
digital signal processor (DSP), or other programmable electronic
logic device such as an application-specific integrated circuit
(ASIC) or field-programmable gate array (FPGA). The controller 950
is coupled to a memory 960 which comprises a work memory and a
storage memory. The memory 960 may for instance be implemented in
the form of RAM, EEPROM, flash memory (e.g. memory card), magnetic
hard disk, or any combination thereof. The memory 960 is capable of
storing program code which is executable by the controller 950 so
as to cause performing of the terminal-side part of the
functionalities as described in various parts of this document. In
alternative embodiments, some or all of the terminal-side
functionality may instead be performed by dedicated hardware.
[0204] The user device 900 has a mobile network interface 952 which
allows the user device 900 to communicate with the first access
network, Access A. The mobile network interface 952 comprises an
internal or external antenna as well as appropriate radio circuitry
for establishing and maintaining a wireless link to a nearby base
station in the first access network, Access A. The radio circuitry
comprises a radio receiver and transmitter formed for instance by
band pass filters, amplifiers, mixers, local oscillators, low pass
filters, AD/DA converters, etc.
[0205] In addition, the disclosed embodiment of the user device 900
has a wireless interface 954 which may be adapted for communication
in accordance with one or more short-range wireless communication
standards such as WiFi (e.g. IEEE 802.11, WLAN), Bluetooth, Near
Field Communication (NFC), or Infrared Data Association (IrDA). In
addition, but not shown in FIG. 9, a serial interface such as USB
may allow the user device 900 to communicate over a serial cable
with for instance a personal computer. Such interfaces may be
absent in other embodiments.
[0206] Communication protocol stacks 958 are provided to allow
communication via any of the interfaces 952 and 954.
[0207] A user interface 962 allows a user 2 to interact with the
user device 900. The user interface 962 includes display means,
such as at least one LCD display, as well as input means for the
user. The input means may e.g. include a keypad with alpha-numeric
keys and/or other keys such as arrow keys (navigation keys) and
functional keys (soft keys), and/or a joystick, touch pad, rotator,
jog dial, etc. The display means and input means may be jointly
realized by a touch-sensitive display in some embodiments. The user
interface 962 typically also involves a loudspeaker and a
microphone.
[0208] The user device 900 may also be provided with other
well-known components, such as power switch, battery, charger
interface, accessory interface, and volume controls; such elements
are however not indicated in FIG. 9 for the sake of brevity.
[0209] To be able to act as a mobile terminal at least with respect
to the first access network, Access A, the user device 900 has a
(U)SIM reader capable of accessing a (U)SIM card 902. The (U)SIM
card 902 comprises electronic circuitry 903 which constitutes a
local (U)SIM controller 903a and a memory 903b. The memory 903b has
a memory area 904 for storing the subscriber identity in the form
of an IMSI number.
[0210] Hence, whenever a permanent IMSI number has been referred to
in the previous drawings and associated description, it is to be
understood that such a permanent IMSI number can be read from the
(U)SIM memory 903b and be presented by the user device 900 to the
access network (Access B or Access A) which it is presently seeking
access to.
[0211] Moreover, whenever a temporary UE identity (such as P-TMSI
or S-TMSI) or a non-IMSI UE identifier has been referred to in the
previous drawings and associated description, it is to be
understood that such a temporary UE identity or non-IMSI UE
identifier can be read from the (U)SIM memory 903b or from the
memory 960 and be presented by the user device 900 to the access
network (Access B or Access A) which it is presently seeking access
to.
[0212] FIG. 10 is a schematic block diagram illustrating an
arrangement 1090 for use in a radio communication system 1110,
wherein the radio communication system 1110 comprises a first
access network 1010 arranged to operate according to a first Radio
Access Technology, and a second access network 1020 arranged to
operate according to a second Radio Access Technology. The first
access network 1010 may, for instance, be the access network
referred to as Access A and/or 510 in the embodiments described
above. The second access network 1020 may, for instance, be the
access network referred to as Access B or 520 in the embodiments
described above.
[0213] As seen in FIG. 10, the arrangement 1090 comprises means
1030 for identifying a user device 1000, when seeking access to the
second access network 1020, through a user device identifier for
the user device, the user device identifier being associated with
the first access network 1010. The user device 1000 may, for
instance, be the device referred to as UE, 500 or 900 in the
embodiments described above. The means 1030 may, for instance, be
the authentication node referred to as AN or 530 in the embodiments
described above, and the means 1030 may, for instance, be adapted
to perform the step 600 in FIG. 5B.
[0214] The arrangement 1090 further comprises means 1040 for
providing information about a context of the user device 1000 in
the first access network 1010 based on the user device identifier.
The means 1040 may, for instance, be the query node referred to as
QN or 540 in the embodiments described above, and the means 1040
may, for instance, be adapted to perform the step 610 in FIG.
5B.
[0215] The arrangement 1090 also comprises means 1050 for
generating an access selection decision for the access sought by
the user device 1000 to the second access network 1020 based on the
provided context information. The means 1050 may, for instance, be
the access selection node referred to as ASN or 550 in the
embodiments described above, and the means 1050 may, for instance,
be adapted to perform the step 620 in FIG. 5B.
[0216] The arrangement 1090 may also comprise means 1060 for
causing the access selection decision to be executed in the radio
communication system 1110. The means 1060 may, for instance, be
adapted to perform the step 630 in FIG. 5B, and it may, for
instance, be adapted to cause the access selection decision to be
executed by appropriately informing the relevant element(s) in the
radio communication system 1110 about the access selection decision
taken, as has been described above under sub-section 4 in this
detailed description section.
[0217] The arrangement 1090 may further comprise means
(collectively referred to as 1070 in FIG. 10), for performing any
or all of the additional functionality described for the
embodiments above and, particularly, any steps of the method
referred to in the summary section of this document.
[0218] Modifications and other variants of the described
embodiment(s) will come to mind to one skilled in the art having
the benefit of the teachings presented in the foregoing
descriptions and the associated drawings. Therefore, it is to be
understood that the embodiment(s) is/are not to be limited to the
specific examples disclosed and that modifications and other
variants are intended to be included within the scope of this
disclosure. Although specific terms may be employed herein, they
are used in a generic and descriptive sense only and not for
purposes of limitation.
* * * * *
References