GB2454970A - Reducing location registration signalling in inter network (inter RAT) handover. - Google Patents
Reducing location registration signalling in inter network (inter RAT) handover. Download PDFInfo
- Publication number
- GB2454970A GB2454970A GB0818030A GB0818030A GB2454970A GB 2454970 A GB2454970 A GB 2454970A GB 0818030 A GB0818030 A GB 0818030A GB 0818030 A GB0818030 A GB 0818030A GB 2454970 A GB2454970 A GB 2454970A
- Authority
- GB
- United Kingdom
- Prior art keywords
- session management
- management state
- state data
- location registration
- bearer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 230000011664 signaling Effects 0.000 title claims abstract description 13
- 238000005516 engineering process Methods 0.000 claims abstract description 28
- 238000000034 method Methods 0.000 claims abstract description 28
- 230000010267 cellular communication Effects 0.000 claims abstract description 6
- 230000001413 cellular effect Effects 0.000 claims description 5
- 230000004044 response Effects 0.000 claims description 3
- 101710104937 Non-specific acid phosphatase Proteins 0.000 claims 1
- 230000008859 change Effects 0.000 description 10
- 206010051686 Pachydermoperiostosis Diseases 0.000 description 5
- 201000006652 primary hypertrophic osteoarthropathy Diseases 0.000 description 5
- 238000012217 deletion Methods 0.000 description 2
- 230000037430 deletion Effects 0.000 description 2
- 238000004705 quadratic configuration interaction calculation Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 230000001960 triggered effect Effects 0.000 description 2
- 241000700159 Rattus Species 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 230000002028 premature Effects 0.000 description 1
- 230000007727 signaling mechanism Effects 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W60/00—Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
- H04W60/005—Multiple registrations, e.g. multihoming
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/14—Reselecting a network or an air interface
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W60/00—Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
- H04W60/04—Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration using triggered events
Abstract
A method is disclosed for reducing signalling between a mobile terminal and a cellular communications network having at least a first bearer technology and a second bearer technology. The method comprise: performing an initial location registration event between the mobile terminal and the cellular communications network; storing session management state data when the terminal enters a state in which the terminal is simultaneously registered with the network over the first and second bearer technologies; when the active bearer technology is changed from the first bearer technology to the second bearer technology, determining the current session management state data and comparing the stored session management state data to the current session management state data; and if the stored session management state data and current session management state data are different, triggering a further location registration event.
Description
TELECOMMUNICATIONS NETWORK
The present invention relates to a cellular telecommunications network having more than one Radio Access Technology (RAT). In particular, the invention relates to improvements in idle state signalling optimisation between "long term evolution" bearer technology (LTE -a so-called 4G technology) and 2G/3G bearer technologies (such as GSM and VMTS).
To receive a new call, a mobile terminal (or user equipment, UE) needs to be registered in a paging area with the network. The terminal maintains this registration through idle state signalling.
Under GSM (and UMTS) standards, location registration signalling at cell boundaries is performed by storing a current Location Area (LA) value, (or, for IJMTS, Routeing Area (RA) value) -this value is associated with a particular cell and thus a respective base station (node B). In idle state, the terminal checks at cell change whether the new cell is still associated with the stored LAIRA -if there has been a change of value the terminal is forced to carry out a location/routing area update (LAU/RAU).
Currently the LTE system has the ability to allow or disallow access of idle state UEs to the system based on the concept of the Tracking Area (TA). Cells are in this case grouped into clusters (containing of the order of 100 cells), with each cluster being given a TA Identity. A UE is either Accepted or Rejected into one or a collection of TAs by a mobility management entity (MME -the LTE analogue to the SGSN in 3G) when the UE performs the TA Update procedure.
When the UE connects (via LTE bearer technology) to an c-node B (eNB) it enters RRC Connected state, which requires the security procedures to be triggered between the UE and the radio access network. Whilst the UE remains in RRC Connected state, the eNB is in control of the lIE mobility. Whilst in RRC Connected state the eNB stores the UE context for that IJE, which is generated from information provided from the UE and from the MME. When the UE moves to RRC Idle state the eNB discards the UE context information.
In idle mode, it will be common that the UE has several evolved packet system (EPS) bearers/primary and secondary PDP contexts active.
These different (LTE, 3G & 2G) contexts could be activated when the UE attaches to LTE. Then the UE moves to LTE-IDLE and then subsequently moves onto its first 2G/3G cell. This should cause a Routeing Area update (RAU) to occur, which will in turn move the session management state from the MME to the SGSN. The session management state includes the S-GW/P-GW/GGSN address.
In circumstances when the liE enters active mode, modifies its session management/EPS bearer state and returns to idle mode, then a simple procedure would be that the UE performs an RA update/TA update at the next idle mode RAT change.
However, short voice calls and/or push to talk over cellular (PoC) sessions on one RAT might frequently involve the establishment of dedicated bearers that arc released before returning to idle. The RAU or TAtJ at next idle mode RAT change would then be strictly superfluous.
It is an object of the invention to address the issues set out above.
In accordance with the present invention there is provided a method for reducing signalling between a mobile terminal and a cellular communications network having at least a first bearer technology and a second bearer technology, the method comprising: a) performing an initial location registration event between the mobile terminal and the cellular communications network; b) storing session management state data when the terminal enters a state in which the terminal is simultaneously registered with the network over the first and second bearer technologies; c) when the active bearer technology is changed from the first bearer technology to the second bearer technology, determining the current session management state data and comparing the stored session management state data to the current session management state data; and d) if the stored session management state data and current session management state data are different, triggering a further location registration event.
Preferably, the step of performing an initial location registration event comprises at least: performing a first location registration from the mobile terminal to the first bearer technology; and performing a second location registration from the mobile terminal to the second bearer technology, the first location registration and second location registration being substantially independent of each other.
Advantageously, the session management state data includes information corresponding to at least one of the following parameters: APNs, NSAPIs, destination IP address(es), source IP address(es), downlink TFTs, uplink TFTs or QCIs.
Alternatively the method may further comprise the step of calculating a checksum from information corresponding to the session management state, wherein the step of determining the current session management state data includes calculating a current checksum from information corresponding to the current session management state.
In this context the stored session management state data and current session management state data may conveniently both be checksums.
If the stored session management state data and current session management state data arc identical, the method preferably includes providing an indication that a further location registration event is unnecessary, thereby overriding the conventional response to any session management state changes made since the most recent location registration event.
After a further location registration event has been triggered, the method preferably comprises repeating steps b) to d) respectively. The current session management state data determined in the first iteration of step c) will then become the stored session management state data in the second iteration of step b).
In accordance with a further aspect of the invention there is provided a mobile terminal arranged to operate in accordance with the method set out above.
In accordance with yet a further aspect of the invention there is provided a cellular telecommunications network arranged to operate in accordance with the method set out above.
There are a number of sets of subscriber data/context in MME and SGSN for which the question of synchronisation must be considered if unnecessary idle state signalling is to be avoided: security contexts; subscriber data; "implicitly detached state" data; and, of most interest to the invention, session management bearer state data. !5
Given the agreement on the SGSN and MN4E performing separate registrations with the HSS, the "idle mode" security contexts in MME and SGSN will be independent.
Consequently, there is no need for procedures to synchronise these.
At handover/relocation, it is believed that the source core network (CN) node will supply the base' security parameters to be used in LTE_active/RRC_connccted mode following the handover. It is assumed that these security parameters are used until the UE moves to idle mode, or, the (new) CN performs an Authentication and Key Agreement (AKA) AND security mode setting procedure: AKA is the security protocol used in UMTS.
Depending upon the Radio Access Technology (RAT), there arc a number of subscriber data parameters which might be considered for synchronisation: for instance QoS Profile, SMS barring, or Trace. Not all parameters arc needed by both MME (LTE) and SGSN (2G/3G). For example, Trace might only be active on one RAT.
The QoS profiles might also be different on the different RATs (eg maximum bit rate).
These types of subscriber data are may indeed not need to be synchronized between MME and SGSN. Instead it is assumed that the HSS downloads a consistent set of data to MME and SGSN.
The term "implicitly detached state" deserves a little explanation. If the mobile is using (either in active mode or idle mode) one RAT for a long period, then the "periodic routeing area timer" will expire in the other RAT and (as agreed in S2-073797) functionality is needed to ensure that the MME/SGSN does not delete the EPS bearers/PDP contexts in the S-GW/GGSN. This may be achieved by signalling between MMEandSGSN.
When the SGSN (or MME) determines that the UE has been inactive for a very long period (eg twice the PR!J timer) in that RAT, it signals this fact to the MME (or SGSN).
When the MME (or SGSN) also determines that the UE is very inactive, then the is MME(or SGSN) can delete the UE's context from the Serving and PDN Gateways AND inform the SGSN (or MME) that this deletion has been done.
If the mobile returns to the first RAT, then that RAT's CN node signals to its peer CN node that the mobile has returned.
Conveniently, in situations of long inactivity from a UE in one RAT, the above signalling mechanisms are used to avoid premature deletion of the PDP contcxts/EPS bearers in the S-GW/P-GW/GGSN.
Synchronisation of session management/evolved packet system (EPS) bearer state presents the most significant challenge to the optimisation of idle state signalling. In idle mode, it will be common that the UE has several EPS bearers/primary and secondary PDP contexts active.
These different contexts could be activated when the UE attaches to LTE. Then the UE moves to LTE-IDLE and later on moves to its first 2G/3G cell. This should cause a Routeing Area update (RAU) to occur, and this can move the Session Management state from the MME to the SGSN. The session management state includes the S-GW/P-GW/GGSN address.
Conveniently, the evolved packet core (EPC) is notified that this is an Idle Mode Signalling Reduction (ISR) Routeing Area (RA) update, and hence instructed not to delete the bearer state information' from the old' MME/SGSN.
Advantageously, a request to activte ISR should be signalled in the Context Request message sent from the SGSN (or MME) to the MME (or SGSN). Acceptance (or not) to of the ISR request should be indicated in the Context response. Both MME and SGSN then store their "ISR peer's lP address".
At MME-MME change, the new MME's IP address may be made known to the old SGSN'. To reduce the number of network interfaces, it is contemplated that the new MME indicates in the TAU accept message, that the UE needs to perform an RAU the next time that it moves to 2G/3G. A similar procedure applies for SGSG-SGSN change.
If the UE enters active mode, modifies its session management/EPS bearer state and returns to idle mode, then a simple procedure would be that the UE performs an RA updatefrA update at the next idle mode RAT change.
However, short voice calls and/or PoC sessions on one RAT might frequently involve the establishment of dedicated bearers that are released before returning to idle. Hence greater signalling reduction could be obtained if the UE stored its "idle mode session management state" (e.g. active PDP contexts/EPS bearers; their TFTs; their NSAPIs/EPS bearer IDs, etc.); checked for changes when next returning to idle and only performed the inter-RAT RA update if there is a change to the "idle mode session management state".
Preferably, if the "idle mode session management state" changes, then the UE performs a TA/RA update at the next inter-RAT change.
in one embodiment, upon entry into tSR active state, the UE stores information to describe its "session management state at entry into tSR active". This session management state information includes some or all of the following parameters: APNs, NSAPIs, destination and source IP addresses, DL-TFTs and/or UL-TFTs, QCIs etc. The mobile may then activate, deactivate and modify bearers, e.g. activation and reason of guaranteed bit rate bearers for a speech call.
At each subsequent RAT change between LTE and 2G/3G, the mobile compares its Jo current session management state information with the "session management state at entry into ISR active". If they are different, then the mobile needs to perform an RAU (if entering 2G/3G) or TA update (TAIJ) (if entering E-UTRAN). If the bearer context information is the same, then previous changes to the bearer context information do not cause an RAU or TAU (although the mobile might still perform a RAU/TAU for other IS reasons, such as movement into a new Routeing Area). If there is no RAU/TAU, the mobile remains in ISR active state.
In an alternative embodiment, upon entry into the ISR active state, the mobile computes and stores a checksum from the "session management state at entry into ISR active". At subsequent inter-RAT changes, the mobile calculates a check sum of the current session management state. If the checksums differ, then a RAU or TAU is needed. If the checksums are the same, then this does not trigger the mobile to perform an RAU/TAU.
As will be apparent from the preceding discussion, support for ISR would be essential for any LTE mobile terminal that also supports 2G and/or 3G. Note that in order to aid inter-operability testing, it may still be necessary for a mobile terminal to signal its support of ISR to the Core Network.
Claims (12)
- CLAiMS: I. A method for reducing signalling between a mobile terminal and a cellular communications network having at least a first bearer technology and a second bearer S technology, the method comprising: a) performing an initial location registration event between the mobile terminal and the cellular communications network; b) storing session management state data when the terminal enters a state in which the terminal is simultaneously registered with the network over the first and second hearer technologies; c) when the active bearer technology is changed from the first bearer technology to the second bearer technology, determining the current session management state data and comparing the stored session management state data to the current session management state data; and is d) if the stored session management state data and current session management state data are different, triggering a further location registration event.
- 2. A method as claimed in claim I, wherein the step of performing an initial location registration event comprises at least: performing a first location registration from the mobile terminal to the first bearer technology; performing a second location registration from the mobile terminal to the second bearer technology, the first location registration and second location registration being substantially independent of each other.
- 3. A method as claimed in claim I or claim 2, wherein the session management state data includes information corresponding to at least one of the following parameters: APNs, NSAP!s, destination lP address(es), source IP address(es), downlink TFTs, uplink TFTs or QCls.
- 4. A method as claimed in claim I or claim 2, further comprising the step of calculating a checksum from information corresponding to the session management state, wherein the step of determining the current session management state data includes calculating a current checksum from information corresponding to the current session management state.
- 5. A method as claimed in claim 4, wherein the stored session management state data and current session management state data arc respective checksums.
- 6. A method as claimed in any one of the preceding claims, further comprising, if the stored session management state data and current session management state data are identical, providing an indication that a further location registration event is unnecessary, thereby overriding the conventional response to any session management state changes made since the most recent location registration event.
- 7. A method as claimed in any one of claims I to 4, wherein after the further is location registration event the method further comprises repeating steps b) to d) respectively, the current session management state data determined in the first iteration of step c) becoming the stored session management state data in the second iteration of step b).
- 8. A mobile terminal arranged to operate in accordance with the method in any of the preceding claims.
- 9. A cellular telecommunications network arranged to operate in accordance with the method in any of claims I to 7.
- 10. A method for reducing signalling as hereinbefore described.
- II. A mobile terminal arranged to operate as hcreinbcforc described.
- 12. A cellular telecommunications network arranged to operate as hercinbefore described.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GBGB0719207.3A GB0719207D0 (en) | 2007-10-02 | 2007-10-02 | Telecommunications network |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB0818030D0 GB0818030D0 (en) | 2008-11-05 |
| GB2454970A true GB2454970A (en) | 2009-05-27 |
Family
ID=38738978
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GBGB0719207.3A Ceased GB0719207D0 (en) | 2007-10-02 | 2007-10-02 | Telecommunications network |
| GB0818030A Withdrawn GB2454970A (en) | 2007-10-02 | 2008-10-02 | Reducing location registration signalling in inter network (inter RAT) handover. |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GBGB0719207.3A Ceased GB0719207D0 (en) | 2007-10-02 | 2007-10-02 | Telecommunications network |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP2046085B1 (en) |
| AT (1) | ATE501619T1 (en) |
| DE (1) | DE602008005383D1 (en) |
| GB (2) | GB0719207D0 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130310035A1 (en) * | 2011-02-19 | 2013-11-21 | St-Ericsson Sa | Subscriber Identity Switch of a Communication Terminal |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8165068B2 (en) * | 2008-04-18 | 2012-04-24 | Research In Motion Limited | User equipment detach with multiple packet data network connectivity |
| GB0908694D0 (en) | 2009-05-20 | 2009-07-01 | Vodafone Plc | Terminating SMS messages in LTE |
| WO2011049370A2 (en) * | 2009-10-21 | 2011-04-28 | Lg Electronics Inc. | Method for determining isr activation in mobile communications system |
| KR101662080B1 (en) * | 2009-10-21 | 2016-10-04 | 엘지전자 주식회사 | Method for determining isr activation in mobile communications system |
| KR101684699B1 (en) * | 2009-10-27 | 2016-12-08 | 노키아 솔루션스 앤드 네트웍스 오와이 | Method for communicating in mobile telecommunication network and system therefor |
| KR20110076733A (en) | 2009-12-29 | 2011-07-06 | 엘지전자 주식회사 | Method for determining isr deactivation in mobile communications system |
| US20110292871A1 (en) * | 2010-05-25 | 2011-12-01 | Tom Chin | Wireless Attachment To Multiple Radio Access Networks At The Same Time |
| EP2464153A1 (en) | 2010-12-10 | 2012-06-13 | ST-Ericsson SA | Switching active subscriber identity of a communication |
| EP3399794B1 (en) * | 2014-02-10 | 2021-06-23 | Telefonaktiebolaget LM Ericsson (publ) | Interworking between networks operating according to different radio access technologies |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006041742A (en) * | 2004-07-23 | 2006-02-09 | Mitsubishi Electric Corp | Handover method, wireless base station, and wireless terminal station |
| WO2008058877A1 (en) * | 2006-11-13 | 2008-05-22 | Nokia Corporation | A fast combinational voice call continuity from lte to 2g/3g cs domain |
| GB2447931A (en) * | 2007-03-28 | 2008-10-01 | Nec Corp | Mobile radio communications device, related network device and method |
-
2007
- 2007-10-02 GB GBGB0719207.3A patent/GB0719207D0/en not_active Ceased
-
2008
- 2008-10-02 EP EP08165792A patent/EP2046085B1/en active Active
- 2008-10-02 AT AT08165792T patent/ATE501619T1/en not_active IP Right Cessation
- 2008-10-02 GB GB0818030A patent/GB2454970A/en not_active Withdrawn
- 2008-10-02 DE DE602008005383T patent/DE602008005383D1/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006041742A (en) * | 2004-07-23 | 2006-02-09 | Mitsubishi Electric Corp | Handover method, wireless base station, and wireless terminal station |
| WO2008058877A1 (en) * | 2006-11-13 | 2008-05-22 | Nokia Corporation | A fast combinational voice call continuity from lte to 2g/3g cs domain |
| GB2447931A (en) * | 2007-03-28 | 2008-10-01 | Nec Corp | Mobile radio communications device, related network device and method |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130310035A1 (en) * | 2011-02-19 | 2013-11-21 | St-Ericsson Sa | Subscriber Identity Switch of a Communication Terminal |
| US9204413B2 (en) * | 2011-02-19 | 2015-12-01 | St-Ericsson Sa | Subscriber identity switch of a communication terminal |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0818030D0 (en) | 2008-11-05 |
| ATE501619T1 (en) | 2011-03-15 |
| GB0719207D0 (en) | 2007-11-14 |
| EP2046085B1 (en) | 2011-03-09 |
| EP2046085A1 (en) | 2009-04-08 |
| DE602008005383D1 (en) | 2011-04-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP2046085B1 (en) | Improvements for idle state signalling in telecommunications networks | |
| US10659999B2 (en) | Intersystem change between different radio access networks | |
| CN108632915B (en) | Method, device and equipment for moving terminal between 4G network and 5G network | |
| AU2010207791B2 (en) | Reducing signalling loads from a mobile network | |
| EP2291014B1 (en) | Method and corresponding terminal for association relationship updating | |
| US9913238B2 (en) | Mobile station, method for controlling mobile station, mobile communication system, mobility management apparatus, and computer-readable medium | |
| US8170566B2 (en) | Telecommunications network | |
| US8600375B2 (en) | Method for optimizing the reduction of mobility signalling at inter-RAT change | |
| US9491732B2 (en) | Paging processing method, user equipment and system | |
| CN110267362B (en) | Method and user equipment for maintaining maximum bearer number | |
| EP2448326A1 (en) | Business processing method, communication device and communication system | |
| CN111567099A (en) | User device | |
| US20160105790A1 (en) | Combined location updating processing method, apparatus, and system | |
| KR20140019548A (en) | Methods for providing communication service between heterogeneous networks | |
| KR102034225B1 (en) | Method to use existing nas signaling connection for pending uplink signaling/data after tau accept | |
| CN116438867A (en) | Periodic registration update procedure for non-allowed service areas |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |