GB2460017A

GB2460017A - Managing network search and selection

Info

Publication number: GB2460017A
Application number: GB0808168A
Authority: GB
Inventors: Chen-Ho Chin; Craig Bishop
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2008-05-06
Filing date: 2008-05-06
Publication date: 2009-11-18
Anticipated expiration: 2028-05-06
Also published as: GB0808168D0; GB2460017B

Abstract

A method of controlling the searching for and/or selection of networks (NWs) by user equipment (UE) comprises communicating a time interval to the UE, storing the time interval in the UE, using the stored time interval to determine when to perform a search using the UE for NWs and performing said search using the UE. Communicating the time interval may comprise communicating the time interval from ANDSF to the UE, for example in a policy response message.

Description

Managing Network Search and Selection

Field of the invention

The present invention is concerned with managing (i.e. controlling or regulating in some manner) the searching for and/or selection of networks by user equipment. In particular, although not exclusively, embodiments of the invention are concerned with managing network (NW) selection attempts in environments such as SAE where ANDSF is present, and with actively providing data that interacts with NW selection.

Background to the Invention

The following abbreviations will be used throughout this specification: ANDSF Access Network Discovery and Selection Function AS Access Stratum.

CN Core Network

DOl Description Of Invention

eNB Enhanced Node B EPC Enhanced Packet Core EPS Enhanced Packet System (For information: eNB + EPC = EPS) HPLMN Home PLMN *:::* HRPD High Rate Packet Data (ie. the 3GPP2 high speed data mobile system) IMS lP MultiMedia Subsystem * S S...

ISIM IMS SIM * **

* LTE Long Term Evolution (relate most to the Radio Access Network) PLMN Public Land Mobile Network PS Packet Switched * .* SAE System Architecture Evolution (relate most to the EPC) *.*.* S-GW SAE Gateway SIM Subscriber Identity Module UE User Equipment UMTS Universal Mobile Telecommunications System

USIM UMTSSIM

VPLMN Visited PLMN The following documents and specifications will also be referred to, and their contents are herein incorporated by reference: [1] S2-083106 "ANDSF" [2] C1-081 396 "ANDSF UE Procedures" [4] TS 22.011 "Service accessibility" [51 TS 23.122" Non-Access-Stratum (NAS) functions related to Mobile Station (MS) in idle mode" [6] TS 23.402 "Architecture enhancements for non-3GPP accesses", version 8.1.1 [71 TS 33.102 "Characteristics of the Universal Subscriber Identity Module (USIM) application" In S2-083 106, [1], it was agreed that "The ANDSF's policy and the UE implementation shall ensure that the UE does not change PLMN more often than the time stored in the USIM (in EFHHPLMN, see TS 31. 102 (XXD for the "periodic network selection attempts" specified in TS22011" *.. It should be noted, however, that there is no such EFHHPLMN USIM file. The correct file *::::* 10 should beEF!.IPPLMN In [7], IS 33.102, subclause 4.2.6, states that should EFHPPLMN have the decode 00', then: : 00': No higher priority PLMN search attempts. * 15

In [4], Is 22.011, subclause 3.2.2.5, one finds: "The interval between attempts shall be stored in the SIM/USIM. Only the service provider shall be able to select for which of the previous situations, periodic network selection shall be attempted and to set the interval, which shall be between 6 minutes and 8 hours, with a step size of 6 minutes. One value shall be designated to indicate that no periodic attempts shall be made ".

This is supported by the statement above regarding the decode "00".

Then [5J, TS 23.122, subclause 4.4.3.3 further elaborates that "If no value is stored in the SIM, a default value of 60 minutes is used." A problem, therefore, is that there is no provision for systems where USIM is not available at the UE, or where USIM is not intended to be issued. For example, in TISPAN, PacketCable many operators have stated they will not be using USIMs. This is even so for W1MAX operators who rather see USIM as an "optional" piece of equipment.

There is no consideration that EFHPPLMN is a property of 3GPP accesses. There are definite use case scenarios that do not consider existence of 3GPP access in a multi-system scenario, eg. Fixed access coupled with WIMAX access eg. Cable access coupled with HRPD accesses.

There is no consideration that the NW selection interval so set in the USIM is one that completely disables the UE from making a periodic NW selection based on time intervals.

The default value and the maximum value set in the USIM EF file can be 60 minutes or 8 hours respectively. This severely disadvantages users in environments where many other (broadband) wireless access systems are available but the equipment is not allowed to select on them for a considerable length of time. * ** * * S

References [4] and [5] have already defined that there be a default value for EFHPPLMN.

In [5], there is the text "If no value is stored in the SIM, a default value of 60 minutes is 1:,. used." Thus, defining a default value has been proposed, but this prior art has only * * 25 discussed a default value for a EFHPPLMN file that is not populated; the existence of a EFHPPLMN file is a necessary prerequisite for this prior art teaching. S.. *

Summary of the invention

It is an aim of certain embodiments of the invention to solve, mitigate or obviate, at least partly, at least one of the problems and/or disadvantages associated with the prior art.

Certain embodiments aim to provide at least one of the advantages described below.

Certain embodiments of the invention are concerned with at least one of the following: Provision of a time interval between NW selection of non-3GPP access NWs and/or other access NWs.

Applying a stated method to regulate time intervals in performing NW selection where either UICC/USIM does not exist.

Applying a stated method to regulate time intervals in doing NW selection where either UICC/USIM does exist but its regulating information for NW selection has disabled the interval of search for NW selection.

According to a first aspect of the present invention there is provided a method of controlling the searching for and/or selection of networks (NWs) by user equipment (UE), the method comprising: communicating a time interval to the UE: storing the time interval in the UE; using the stored time interval to determine when to perform a search using the UE for NWs; and performing said search using the UE.

In certain embodiments, communicating the time interval comprises communicating the time interval from ANDSF to the UE. For example, the ANDSF may provide the time interval (which may also be referred to as a default periodic NW search time) in the Policy Response message. * .-*. . l' *

:. 25 In certain embodiments, communicating the time interval to the UE comprises sending a message containing the time interval to the UE. The method may then comprise sending said message in response to a message sent from the UE. In certain embodiments, the message sent from the UE is a policy request message, and the message sent to the UE is a policy response message.

In certain embodiments, the method further comprises a step of: deciding whether to communicate the time interval to the UE.

In certain embodiments, performing said search comprises searching for non-3GPP networks.

In certain embodiments, the UE is subscribed to networks of a first type, and performing said search comprises searching for networks of a different type. In other words, the NWs in question (being searched for) in certain embodiments are of a different sort than those associated with the main subscription (e.g. USIM) of the UE.

In certain embodiments, storing the time interval in the UE comprises storing the time interval in static memory (or other such memory) of the UE, whereby the stored value will be available for use by the UE even after switching power off, and then switching UE power back on.

In certain embodiments, using the stored time interval to determine when to perform said search comprises starting a timer and comparing a value of the timer with the stored time interval.

In certain embodiments, the method comprises performing said search when the timer value equals the stored time interval.

In certain embodiments, the method further comprises the step of: if the search identifies a plurality of networks, selecting one of said plurality of networks according to at least one predetermined criterion or rule.

*.. In certain embodiments, the method further comprising the steps of: if the search identifies a plurality of networks, presenting an indication of said * plurality of networks to a user of the UE; and 25 selecting one of said plurality of networks according to an input by a user to the UE in response to said indication. * Is

In other words, after performing the search for NWs, the user may be allowed / *s...I * * prompted to select a NW, rather than the selection being fully automated (as would be the case if the UE made the selection according to predetermined/pre-programmed rules or criteria, or other information communicated to it).

Another aspect of the invention provides user equipment (e.g. a mobile phone/handset, PDA, other portable device etc) comprising: a receiver for receiving a message containing a time interval; a memory adapted to store a received time interval; processing means adapted to use the stored time interval to determine when to perform a search for networks; and search means adapted to perform said search.

Another aspect provides a communication system comprising at least one network and UE adapted to carry out a method in accordance with the first aspect.

Another aspect provides user equipment for a communication system as defined immediately above.

Another aspect provides a computer program comprising instructions arranged, when executed, to implement a method andlor a system as claimed in any claim of this

specification.

Another aspect provides machine-readable storage storing a program as defined immediately above.

Brief Description of the Drawings

Embodiments of the invention will now be described with reference to the accompanying *:.::* drawings, of which: Fig. 1 illustrates part of a method embodying the invention and the exchange of certain : .**. messages therein; 25 Fig. 2 is a flow chart illustrating the steps in a method embodying the invention; * S. Fig. 3 is a flow chart illustrating part of a method embodying the invention and in which a *SS.SS * dynamically provisioned NW search timer is managed; Fig. 4 illustrates the use of a guard timer in certain embodiments of the invention; Fig. 5 is a flow chart illustrating another method embodying the invention; Fig. 6 is a flow chart illustrating another method embodying the invention; Fig. 7 is a diagram illustrating the SAE/LTE reference architecture as defined by 3GPP; Fig. 8 is another diagram illustrating the SEA/LTE reference architecture; Fig. 9 illustrates an architecture for access network discovery support functions useful in understanding the invention; and Figs. 10, 11 and 12 illustrate the PLMN selection process for 3GPP.

Description of Embodiments of the Invention

One method embodying the invention provides Dynamic Provisioning of a NW Search Timer (i.e. a time interval for determining when to perform NW searching and/or selection). _This method includes a new element, a new attribute within the chosen communication messages.

In this method, the time interval labelled TpenodIc_NW_search is provided through the 814, S15 reference points as part of the communications between UE and ANDSF. The S14 and S15 reference points are as defined in Annex B below.

The protocol to allow for this communication is currently being developed; it is envisaged that it will be through a selection of IETF protocols. With the selected protocol the means *... of communicating between UE and ANDSF is thus provided. S... * S S...

* In this method embodying the invention a new attribute is introduced to this :.. 25 communication protocol, an attribute that could be named "Timer_for_periodic_NW_search_and_select", or something similarly named such as * .. TperiodiQNW_search and which denotes a time interval for determining the periodicity at :.: which NW searching is performed.

*.S..* * * Figure 1 illustrates this method whereby the new attribute (variable/parameter/value), the time interval, is in the message Policy Response.

In the illustration given in Figure 1 what is shown is one typical communication message that can provide this new attribute. This new attribute can be provided in all or any of other communication messages that may be sent between ANDSF and UE Figure 2 shows a logical flow for this operation.

Certain methods embodying the invention comprise Managing the Dynamically Provisioned NW Search Timer (time interval). As will be appreciated from the background to the invention (above), in the prior art default values have been proposed, but these have been default values for a USIM/SIM EF file EFHPPLMN. Certain embodiments of the invention, in contrast, provide a way to manage periodicity of NW search should there be no USIM/SIM and so no default value as set out in [41 and [5].

Methods embodying the invention can also be applied should there exist a USIM/SIM that supports the EF file EFHPPLMN.

In certain embodiments of the invention, when the attribute Timerjor_Periodic_NW_search_andselect (i.e. the time interval) is received by the UE, the UE stores this in its static memory. This stored value will be thus available for use by the UE even after power-OFF and re-Power-ON. Secondly, this will mean that the NW Search Timer provided by the communication exchange (as shown in Fig. 1) is distinct and not conflicting with the value in the EF file EFHPPLMN.

An advantage of this method is that with a separate complementary stored value, UEs without a USIM/SIM or even a "soft" USIM/SIM/ISIM can still meet the requirement to guard periodicity of NW search.

Furthermore, having a dedicated value guarding periodic NW search means that this separate dedicated value can be set to match the needs of the non-3GPP access * system. It should be noted that EFHPPLMN is essentially for the 3GPP system and for use :.: 25 where there is USIM/SIM plus. There will, however, be use cases (applications of * embodiments of the invention) where there will be no 3GPP system involved and/or no USIM/SIM present. *

**.*.* * Figure 3 illustrates such a method embodying the invention.

Embodiments of the invention may utilise one or both of the Timerjor_Periodic_NWsearch...and_select and the timer of EFHPPLMN as follows.

It is envisaged that when a UE is in 3GPP accesses that it continued stay and PLMN reselection within 3GPP accesses will be guided solely by the guard timer whose value is given in EFHPPLMN. Let's call this timer T(EFHPPLMN). This behaviour is specified in 23.122 [5] an extract from which is copied in Annex c.

For a single radio UE, because [6] clearly requires that the non-3GPP accesses search and selection mechanism "shall not interfere" with the 3GPP accesses mechanism, it is expected that human user intervention is needed to select out of 3GPP access to non- 3GPP access much like above, although for the one-radio UE, it will be a "jump" to the non-3GPP accesses based on info it receives from ANDSF. Upon reaching and successfully selecting onto the non-3GPP access, the time interval Timer_for_periodic_NW_search_and_select will be run to guard the periodicity of search and selection for another PLMN(s).

An illustration of use of T(EFHPPLMN) in 3GPP access is given in Figure 4.

Certain embodiments of the invention provide a Method applicable to single/dual/multi radio UE with SIM/UISM/ISIM, as follows.

For a dual radio UE (ie. UE with two radio parts), it is proposed that T(EFHPPLMN) is run for the 3GPP stack and Timer_for_Periodic_NW_search_and_select in run for the non- 3GPP stack. Upon expiry of Timer_for_Periodic_NW_search_and_select, (in other * : words when a timer value reaches the stored time interval) a search of available non- 3GPP accesses is performed. A network from what is found is either selected based on * the policies the UE knows (for instance provided by ANDSF, or indeed predetermined or :.: 25 pre-programmed by other means) or the human user is offered a choice, to select onto these other non-3GPP access PLMNs. It could also be a combination of both of these.

* *. In other words, the NW search may find a plurality of NWs, and the selection of a NW from this plurality may be fully automated, may be made by a user, or may comprise a ****** * combination of a degree of automated selection according to rules/algorithms etc and a degree of choice by a user. This is illustrated in Figure 5.

Naturally this illustration can only apply to embodiments in which the UE (single, dual radio or otherwise) has SIM/USIM/ISM.

Certain methods embodying the invention are applicable to single/dual/multi radio UE without SIM/UISM/ISIM, as follows.

There will be operational scenarios where a hard SIM/USIM/ISIM is not available. It maybe that even a usoftI SIM/USIM/ISIM is also not available. The method here applies the use of timer Timer_for_Periodic_N W_search_and_select to UEs (whether single radio or dual radio) who might not host hard or soft" SIM/USIM/ISIM or even if they host a "soft SIM/USIM/ISIM does not have the file EFHPPLMN. See Figure 6.

In this use case scenario (ie. UE without even a "soft" SIM/USIM/ISIM) in such an instance the derivation of Timer_for_Periodic_NW_search_and_select can be from the method previously detailed above.

It will be appreciated that embodiments of the present invention can be realized in the form of hardware, software or a combination of hardware and software. Any such software may be stored in the form of volatile or non-volatile storage such as, for example, a storage device like a ROM, whether erasable or rewritable or not, or in the form of memory such as, for example, RAM, memory chips, device or integrated circuits or on an optically or magnetically readable medium such as, for example, a CD, DVD, magnetic disk or magnetic tape or the like. It will be appreciated that the storage devices and storage media are embodiments of machine-readable storage that are suitable for storing a program or programs comprising instructions that, when executed, implement embodiments of the present invention. Accordingly, embodiments provide a program comprising code for implementing a system or method as claimed in any one of the claims of this specification and a machine-readable storage storing such a program.

* * Still further, such programs may be conveyed electronically via any medium such as a communication signal carried over a wired or wireless connection and embodiments suitably encompass the same. * **

Throughout the description and claims of this specification, the words "comprise" and S.....

* "contain" and variations of the words, for example "comprising" and "comprises", means "including but not limited to", and is not intended to (and does not) exclude other moieties, additives, components, integers or steps.

Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.

It will be also be appreciated that, throughout the description and claims of this specification, language in the general form of "X for Y" (where Y is some action, activity or step and X is some means for carrying out that action, activity or step) encompasses means X adapted or arranged specifically, but not exclusively, to do Y. Annex A: SAE/LTE Reference Network Architecture Fig.7 (Figure A.1) -extracted from 23.401 -gives an illustration of the SAE/LTE reference architecture as defined by 3GPP.

Fig. 7 (Figure A.1) shows the 2G GSM/GPRS system (GERAN + SGSN) and the 3G UMTS system (UTRAN + SGSN). By that one is able to the see the "link-up" from/to the 3GPP 2G and 3G system and 3GPP's SAE/LTE.

*,.. The ideas, methods and claims in the main part of this document refer to EPC and EPS, I...

and in particular refer to possible Interworking Functions within the EPC. To help * * visualize the scope of EPC, Figure 8 is provided. For Figure 8, it should be noted that ** 25 EPG also encompasses the HSS. * S. * . .

Annex B: ANDSF and S14, S15 reference points. * S

Below is an extract from TS 23.402, [6], giving the architecture layout of the ANDSF and the S14 and S15 reference points through which UE and ANDSF communicates. It shall be noted that the dated version 8.1.1 of IS 23.402, [6], is used.

Fig. 9 (Figure 4.8.1.1-1) shows Architecture for Access Network Discovery Support Functions 4.8.1 Architecture for Access Network Discovery Support Functions The following architecture may be used for access network discovery and selection. The support and the use of these functions and interfaces are optional.

4.8.3 Reference Points S14 This reference point is between UE and ANDSF for direct queries via pull. It enables dynamic provision of information to the UE for NW discovery and selection procedures related to non-3GPP accesses. Push and/or combination of Pull-Push may be supported as well".

S15 This reference point enables dynamic exchange of information between ANDSF and non-3GPP IP access. It is FFS for which non-3GPP IP accesses this interface is needed and supported. It is FFS which mechanisms (push or pull) are supported. It is FFS how information received from ANDSF is utilized by a particular access system.

Protocol assumption: S14 interface is realized above IP level.

Appendix C Figures 10, 11 and 12 are copied from 3GPP IS 23.122 to illustrate the existing PLMN selection process for 3GPP * ** * * S * .* **.. * S **.S * *5 e S S *SS *

S ***

S * S. * S S

S..... * 0

Claims

Claims 1. A method of controlling the searching for and/or selection of networks (NWs) by user equipment (UE), the method comprising: communicating a time interval to the UE: storing the time interval in the UE; using the stored time interval to determine when to perform a search using the UE for NWs; and performing said search using the UE.
2. A method in accordance with claim 1, wherein communicating the time interval comprises communicating the time interval from ANDSF to the UE.
3. A method in accordance with any preceding claim, wherein communicating the time interval to the UE comprises sending a message containing the time interval to the UE.
4. A method in accordance with claim 3, comprising sending said message in response to a message sent from the UE.
5. A method in accordance with claim 4, wherein the message sent from the UE is a policy request message, and the message sent to the UE is a policy response message. * * * .w.

*
6. A method in accordance with any preceding claim, further comprising a step of: :,:. 25 deciding whether to communicate the time interval to the LiE. *

* **
7. A method in accordance with any preceding claim, wherein performing said -: search comprises searching for non-3GPP networks.

*..*.* * I
8. A method in accordance with any preceding claim, wherein the UE is subscribed to networks of a first type, and performing said search comprises searching for networks of a different type.
9. A method in accordance with any preceding claim, wherein storing the time interval in the UE comprises storing the time interval in static memory of the UE.
10. A method in accordance with any preceding claim, wherein using the stored time interval to determine when to perform said search comprises starting a timer and comparing a value of the timer with the stored time interval.
11. A method in accordance with claim 10, comprising performing said search when the timer value equals the stored time interval.
12. A method in accordance with any preceding claim, further comprising the step of: if the search identifies a plurality of networks, selecting one of said plurality of networks according to at least one predetermined criterion or rule.
13. A method in accordance with any preceding claim, further comprising the steps of: if the search identifies a plurality of networks, presenting an indication of said plurality of networks to a user of the UE; and selecting one of said plurality of networks according to an input by a user to the UE in response to said indication.
14. User equipment comprising: a receiver for receiving a message containing a time interval; a memory adapted to store a received time interval; *:::: processing means adapted to use the stored time interval to determine when to perform a search for networks; and ." 25 search means adapted to perform said search.* *
15. A communication system comprising at least one network and UE adapted to carry out a method in accordance with any one of claims 1 to 13.* I.*.S

S
16. User equipment for a communication system in accordance with claim 15.
17. A computer program comprising instructions arranged, when executed, to implement a method as claimed in any preceding claim and/or a system as claimed in any preceding claim.
18. Machine-readable storage storing a program as claimed in claim 17.