1. A method for a mobile communication system, the method comprising: initiating a TAU (Tracking Area Update) procedure with MME (Mobility Management Enti ty) change or an RAU (Routing Area Update) procedure wit5 h SGSN (Serving GPRS Support Node) change; and activating a user plane setup procedure if a new MME or a new SGSN receives a DDN (Downlink Data Notification) message while a UE (User Equipment) is connected to the new MME or the new SGSN in the TAU procedure 10 or the RAU procedure.

2. The method according to Claim 1, wherein the DDN message is sent to page the UE from an SGW (Serving Gateway) to the new MME or the new SGSN. 15

3. The method according to Claim 1 or 2, wherein the user plane setup procedure is activated even if an active flag is not set in a TAU request message in the TAU procedure or an RAU request message in the RAU procedure. 20

4. The method according to any one of Claims 1 to 3, wherein the user plane setup procedure is activated in conjunction with a TAU accept message in the TAU procedure or an RAU accept message in the RAU procedure. 25

5. A method for a mobile communication system, the method comprising: initiating, by a UE (User Equipment), a TAU (Tracking Area Update) procedure with MME (Mobility Management Entity) change or an RAU (Routing Area Update) procedure with SGSN (Serving GPRS Support Node) change; and 30 sending, by an old MME or an old SGSN, a signal including information that a PGW (Packet Data Network Gateway) initiated signal is temporarily rejected due to mobili ty procedure in progress to the PGW via an SGW (Servi ng Gateway) if the old MME or the old SGSN receives the PGW initiated signal during the TAU procedure or the RAU procedure. 26

6. The method according to Claim 5, further comprising: upon reception of the signal, starting a locally configured guard timer b y the PGW. 5

7. A mobile communication system comprising: a UE (User Equipment); and a plurality of MMEs (Mobility Management Entities) or a plurality of SGSNs (Serving GPRS Support Nodes); 10 wherein the UE initiates a TAU (Tracking Area Update) procedure with MME change or an RAU (Routing Area Update) procedure with SGSN change, and wherein a user plane setup procedure is activated if a new MME or a new SGSN receives a DDN (Downlink Data Notification) message while the UE is connected to the new MME or the new SGSN in the TAU procedure or the RAU 15 procedure.

8. The mobile communication system according to Claim 7, wherein the DDN message is sent to page the UE from an SGW (Serving Gateway) to the new MME or the new SGSN. 20

9. The mobile communication system according to Claim 7 or 8, wherein the user plane setup procedure is activated even if an active flag is not set in a TAU request message in the TAU procedure or an RAU request message in the RAU procedure. 25

10. The mobile communication system according to any one of Claims 7 to 9, wherein the user plane setup procedure is activated in conjunction with a TAU accept message in the TAU procedure or an RAU accept message in the RAU 30 procedure.

11. A mobile communication system comprising: a UE (User Equipment); a plurality of MMEs (Mobility Management Entities) or a plurality of 27 SGSNs (Serving GPRS Support Nodes); an SGW (Serving Gateway); and a PGW (Packet Data Network Gateway), wherein the UE initiates a TAU (Tracking Area Update) procedure with MME change or an RAU (Routing Area Update) procedure with SGSN change, an5 d wherein an old MME or an old SGSN sends a signal including information that a PGW initiated signal is temporarily rejected due to mobili ty procedure in progress to the PGW via the SGW if the old MME or the old SGSN receives the PGW ini tiated signal during the TAU procedure or the RAU 10 procedure.

12. The mobile communication system according to Claim 11, wherein upon reception of the signal, the PGW starts a locally configured guard timer. 15

13. A mobile terminal used in a mobile communicat ion system, the mobile terminal comprising: means for initiating a TAU (Tracking Area Update) procedure with MME (Mobility Management Entity) change or an RAU (Routing Area Update) 20 procedure with SGSN (Serving GPRS Support Node) change, wherein the mobile terminal causes a user plane setup procedure to activate if a new MME or a new SGSN receives a DDN (Downlink Data Notification) message while the mobi le terminal is connected to the new MME or the new SGSN in the TAU procedure or the RAU procedure. 25

14. The mobile terminal according to Claim 13, wherein the DDN message is sent to page the mobi le terminal from an SGW (Serving Gateway) to the new MME or the new SGSN. 30 15. The mobile terminal according to Claim 13 or 14, wherein the user plane setup procedure is activated even if an active flag is not set in a TAU request message in the TAU procedure or an RAU request message in the RAU procedure. 28

16. The mobile terminal according to any one of Claims 13 to 15, wherein the user plane setup procedure is activated in conjunction with a TAU accept message in the TAU procedure or an RAU accept message in the RAU procedure. 5

17. A network node for a mobile communication system including an SGW (Serving Gateway) and a PGW (Packet Data Network Gateway) , the network node comprising: managing means for managing a UE (User Equipment); and 10 reception means for receiving an area update request from the UE via a base stat ion in an area update procedur e, wherein the network node sends a signal including information that a PGW initiated signal is temporarily rejected due to mobility procedure in progress to the PGW via the SGW if the network node receives the PGW initiated signal during 15 the area update procedure with change of the network node initiated by the UE.

18. The network node according to Claim 17, wherein the network node is an MME (Mobi lity Management Ent ity) or an SGSN (Serving GPRS Support Node). 20

19. The network node according to Claim 17 or 18, wherein the area update request is a TAU (Tracking Area Update) request or an RAU (Routing Area Update) request, and the area update procedure is a TAU procedure or an RAU procedure. 25

20. A PGW (Packet Data Network Gateway) for a mobile commun ication system, the PGW comprising: means for connect ing to an external network, wherein the PGW receives a signal including information that a PGW 30 initiated signal is temporarily rejected due to mobility procedure in progress from an old MME (Mobili ty Management Entity) or an old SGSN (Serving GPRS Support Node) via a SGW (Serving Gateway) if the old MME or the old SGSN receives the PGW ini tiated signal during a TAU (Tracking Area Update) procedure with MME change or an RAU (Routing Area Update) procedur e with SGSN change 29 initiated by a UE (User Equipment), and wherein the PGW starts a locally configured guard timer.

METHOD FOR MOBILE COMMUNICATION SYSTEM, MOBILE
COMMUNICATION SYSTEM, MOBILE TERMINAL, NETWORK NODE, AND
PGW
5
Technical Field
[0001]
The present invention relates to a communication system, an MME and a
communicat ion method and, for example, relates to a communication system, an
10 MME and a communication method that perform call control for an UE.
Background Art
[0002]
In the 3GPP (Third Generation Partnership Project) that defines a standard
for mobile network systems, an EPC (Evolved Packet Cor e) is specified as the next
15 generat ion mobile network system. The EPC is a network system that
accommodates an LTE (Long Term Evolut ion) access network in addition to
wireless access networks called the second generation and the third generation.
[0003]
Incoming packet call processing in the EPC is described hereinafter. In
20 Non-Patent Li terature 1, incoming packet call processing in the case where a UE
(User Equipment) representing a user terminal is in the idle mode is disclosed.
The state where the UE is in the idle mode is the state where the UE is not
connected with the EPC. In other words, a radio bearer between the UE and the
EPC is disconnected in this state. In such a case, when an incoming packet cal l is
25 made to the UE, an SGW (Serving Gateway) , which is a bearer management device,
sends an incoming call notification message to an MME (Mobili ty Management
Entity) or an SGSN (Serving GPRS Support Node) that manages the UE.
Receiving the incoming cal l notification message, the MME or SGSN sends a
Paging message to an eNB (evolved Node B) or a NodeB, which is a base station,
30 in order to call the UE. Receiving the Paging message, the eNB or NodeB
performs Page processing on a plural ity of UEs located in the area managed by
itself. The UE to be cal led sends a response message to the eNB or NodeB and
connects to the EPC.
[0004]
35 In this manner, even when an incoming packet call is made to the UE in the
2
idle mode which is not connected with the EPC, i t is possible to perform data
communicat ion with the UE by calling the UE from the network side.
Citation List
Non Patent Literature
[00055 ]
[NPL1] 3rd Generation Partnership Project; Technical Specification Group
Services and System Aspects; General Packet Radio Service (GPRS) enhancements
for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access
(Release 12), 3GPP TS 23.401 V12.0.0 (2013-03), clauses 5.3.4.3, 5.3.3.2
10 Summary of Invention
Technical Problem
[0006]
However, in the incoming packet call processing disclosed in Non Patent
Li terature 1, the following problem occurs. Normally, when the UE moves out of
15 a location registration area managed by the MME, the UE sends a location
registration request (Tracking Area Update Request) message to a new MME that
manages a location registration area to which the UE is to move. Receiving the
location registration request message, the new MME performs location registration
of the UE. After the location registration in the new MME is done, the UE
20 becomes the state where it is registered in the n ew MME that manages the location
registration area to which it is to move.
[0007]
When an incoming packet call arrives to the UE after the UE sends the
location registration request message and before processing for movement is done
25 in the new MME, the problem that it is not possible to normally call the UE to be
called occurs.
[0008]
For example, when an incoming packet call arrives to the UE after the UE
sends the location registration request message and before processing for
30 movement is done in the new MME, the SGW sends the incoming cal l notification
message to the MME that has managed the location of the UE before movement .
Receiving the incoming cal l notification message, the MME sends a Paging
message to a base station under its control ; however, because the UE to be called
has moved out to the area managed by the new MME, it is not possible to call the
3
UE. In other words, when an incoming packet call is made while the UE is during
its movement which involves a change in the MME, the problem that the UE cannot
receive the incoming packet occurs.
[0009]
Alternatively, when, after the UE sends the location registration reques5 t
message, the SGW recognizes a new MME to manage the location of the UE after
movement, the SGW sends the incoming call noti fication message to the new MME.
In this case also, when the UE has not received a response message to the Tracking
Area Update Request message, and Tracking Area Update processing is not done,
10 the problem that the UE cannot normally receive the incoming packet occurs.
[0010]
An exemplary object of the present invention is to provide a
communicat ion system, an MME and a communicat ion method that perform control
so as to reliably receive an incoming packet call that is made during movement of a
15 UE.
Solution to Problem
[0011]
A communication system according to a first exemplary aspect of the
invention includes an MME that, by movement of a UE, performs Tracking Area
20 Update processing that changes a locat ion registration area of the UE and manages
the location registration area of the UE before change, and a PGW that sends, to
the MME, a control signal required to be notified to the UE during execution of the
Tracking Area Update processing, wherein the MME receives the control signal,
and sends a response signal indicat ing that the Tracking Area Update processing is
25 being executed to the PGW, and, after completion of the Tracking Area Update
processing, the PGW sends the control signal to an MME that manages the location
registration area of the UE after change.
[0012]
An MME according to a second exemplary aspect of the invention is an
30 MME that , by movement of a UE, performs Tracking Area Update processing that
changes a location registration area of the UE and manages the location
registration area of the UE before change, wherein the MME receives a control
signal sent from a PGW and required to be notified to the UE during execution of
the Tracking Area Update processing, and in response to receiving the control
4
signal, sends a response signal indicating that the Tracking Area Update
processing is being executed to the PGW, and, after complet ion of the Tracking
Area Update processing, causes the PGW to send the control signal to an MME that
manages the location registration area of the UE after change.
[005 13]
A communication method according to a third exemplary aspect of the
invention is a communication method in an MME that, by movement of a UE,
performs Tracking Area Update processing that changes a locat ion registration
area of the UE and manages the location registration area of the UE before change,
10 the method including receiving a control signal sent from a PGW and required to
be notified to the UE during execut ion of the Tracking Area Update processing, in
response to receiving the control signal , s ending a response signal indicat ing that
the Tracking Area Update processing is being executed to the PGW, and after
completion of the Tracking Area Update processing, causing the PGW to send the
15 control signal to an MME that manages the location registrat ion area of the UE
after change.
Advantageous Effects of Invention
[0014]
According to an exemplary embodiment of the invention, it is possible to
20 provide a communication system, an MME and a communicat ion method that
perform control so as to rel iably rec eive an incoming packet call that is made
during movement of a UE.
Brief Description of Drawings
[0015]
25 Fig. 1 is a configurat ion diagram of a communication system according to
first, second and third exemplary embodiments;
Fig. 2 is a view showing a flow of processing to connect a UE to a mobile
communicat ion system according to the first, second and third exemplary
embodiments;
30 Fig. 3 is a view showing a flow of processing when notifying a PGW
activation control signal to a UE according to the first ex emplary embodiment;
Fig. 4 is a view showing a flow of a location information update
processing according to the first , second and third exemplary embodiments;
Fig. 5 is a view i llustrat ing a processing sequence in the communication
5
system according to the second exemplary embodiment;
Fig. 6 is a view showing a modified example of the processing sequence in
the communication system according to the second exemplary embodiment ;
Fig. 7 is a view showing a modified example of the processing sequence in
the communication system according to the second exemplary embodiment ; an5 d
Fig. 8 is a view showing a modified example of the processing sequence in
the communication system according to the second exemplary embodiment .
Description of Embodiments
[0016]
10 [Fi rst exemplary embodiment]
Exemplary embodiments of the present invention are described hereinafter
with reference to the drawings. A configuration example of a communicat ion
system according to a first exemplary embodiment of the present invention is
described hereinafter with reference to Fig. 1. In this figure, a mobile
15 communicat ion system that is defined in the 3GPP is described. The
communicat ion system in Fig. 1 includes a PGW (Packet Data Network GateWay)
75, an old SGW (Serving GateWay) 15, a new SGW 85, an old MME 25, a new
MME 35, a UE 45, an eNB 55 and an eNB 65.
[0017]
20 The UE 45 is a communication device that is specified as a mobi le
terminal device in the 3GPP. The UE 45 may be a cellular phone, a smartphone, a
tablet terminal, a personal computer with a communicat ion function or the like, for
example. Further, the UE 45 may be an M2M (Machine To Machine) device that
performs communicat ions in an autonomous manner. The M2M device may be a
25 device that does not often move such as an automat ic vending machine or an
electrical appliance having a communication function, or a watch worn by a user
and the like, for example.
[0018]
The eNB55 and eNB 65 are node devices specified as base stations in the
30 3GPP. Each of the eNB 55 and eNB 65 forms a wireless communication area and
communicates with the UE that is located in the wireless communication area
managed by itself.
[0019]
The PGW 75 is a node device that is located at the boundary between the
6
mobile communicat ion system and the external network. The PGW 75 sends a
PGW 75 activation control signal to the old MME 25 or the new MME 35. The
PGW 75 activation control signal is a control signal that is generated in the PGW
75 and that needs to be notified to the UE 45.
[00205 ]
Each of the old MME 25 and the new MME 35 defines a location
registration area that manages the location of the UE. In the location registration
area managed by each of the old MME 25 and the new MME 35, a plural ity of eNB
may be located. In other words, the location regi stration area may include a
10 plurality of wireless communicat ion areas formed by the eNB.
[0021]
When the UE 45 moves from the location registration area defined by the
old MME 25 to the location registration area defined by the new MME 35, the UE
45 sends a location registration request message to the new MME 35. Receiving
15 the location registration request message sent from the UE 45, the new MME 35
performs processing for movement of the UE 45. The processing for movement
of the UE 45 is processing that the new MME 35 registers the UE 45 as a device to
be managed, for example. Further, when the new MME 35 receives the locat ion
registration request message sent from the UE 45, it sends a message to the old
20 MME 25. The old MME 25 is an MME that manages the locat ion registration area
from which the UE 45 moves. The message that is notified from the new MME 35
to the old MME 25 is a message indicating that the UE 45 has moved to the
location registration area defined by the new MME 35. The UE 45 may add an
identifier of the old MME 25 that manages the location registration area before
25 movement to the location registration request message for the new MME 35. The
new MME 35 can thereby detect the old MME 25 that manages the location
registration area from which the UE 45 moves. The old MME 25 receives the
message from the new MME 35 and can thereby detect that the UE 45 has moved to
the location registration area defined by the new MME 35.
30 [0022]
Although the case where the MME that manages the location r egistration
area of the UE 45 is changed is described in this figure, there is also case where
the UE 45 moves from an LTE communication to a 2G or 3G communication area.
In this case, the node device that manages the location registration area of the UE
7
45 is changed from the MME to the SGSN. When the UE 45 moves to a 2G or 3G
communicat ion area, the UE 45 connects to a NodeB and an RNC (Radio Network
Controller). Further, there is a case where the UE 45 moves from a 2G or 3G
communicat ion area to a 2G or 3G communication area. In this case, the SGSN
that manages the location registration area of the UE 45 is changed in some cases5 .
[0023]
Hereinafter, a flow of processing to connect the UE to the mobi le
communicat ion system according to the first exemp lary embodiment of the
invention is described with reference to Fig. 2. First , when a power switch is
10 pressed by a user and a power is turned on, the UE 45 sends an Attach Request
message as the location registrat ion request message to the eNB 55 (S11). Next,
the eNB 55 sends the Attach Request message sent from the UE 45 to the old MME
25 (S12). Receiving the Attach Request message, the old MME 25 generates
location registration information of the UE 45. The location registration
15 information contains information indicating that the UE 45 is located wi thin the
location registration area managed by its own device or subscriber information of
the UE 45, for example. The subscriber information of the UE 45 may be
acquired from a subscriber information management device (not shown) that is
placed in the mobile communicat ion system. The subscriber information
20 management device is specified as an HSS (Home Subscriber Server) in the 3GPP,
for example. Then, the old MME 25 notifies the subscriber information o f the UE
45 to the old SGW 15 using a Create Session Request message (S13). Then, the
old SGW 15 sends a Create Session Response message to the old MME 25 as a
response message to the Create Session Request message (S14). By receiving the
25 Create Session Request message, the old SGW 15 can identify the MME that
manages the location of the UE 45. Further, by the sending of the Create Session
Response message, a session for the UE 45 is established between the old MME 25
and the old SGW 15.
[0024]
30 Receiving the Create Session Response message, the old MME 25 sends an
Attach Accept message to the eNB 55 (S15). The Attach Accept message
corresponds to a response signal to the Attach Request message. By sending the
Attach Accept message, the old MME 25 compl etes registration processing of the
UE 45. The completion of registration processing of the UE 45 means the
8
completion of movement processing of the UE 45. After that , the eNB 55 sends
an Attach Accept message to the UE 45 (S16).
[0025]
By receiving the Attach Accept message, the UE 45 becomes connected to
the mobile communication system. The state where the UE 45 is connected to th5 e
mobile communicat ion system may be referred to as the state where the UE 45 is
attached to the mobile communication syst em.
[0026]
Although the flow of processing when the power of the UE 45 is turned on
10 is described above, the same processing is executed also when the location
registration area where the UE 45 is located changes in order to generate location
registration informat ion in a new MME. When the location registration area
where the UE 45 is located changes, the UE 45 sends a Tracking Area Update
Request message instead of the Attach Request message. Further, the old MME
15 25 and the SGW 15 send and receive Modify Bearer Request/Modify Bearer
Response messages instead of the Create Session Request/Create Session Response
messages.
[0027]
Hereinafter, a flow or processing performed when the PGW 75 according
20 to the first exemplary embodiment of the present invention notifies a PGW 75
activation control signal to the UE 45 is described with reference to Fig. 3. In
this example, it is assumed that the processing of Fig. 2 is completed, and the UE
45 is located in the location registrat ion area managed by the old MME 2 5.
[0028]
25 First, when the UE 45 detects that i t has moved from the locat ion
registration area managed by the old MME 25 to another locat ion registrat ion area,
the UE 45 sends a Tracking Area Update Request message to the eNB 65 (S21).
The eNB 65 manages the location registrat ion area to which the UE 45 has moved.
The UE 45 may detect that the location registration area has changed by receiving
30 annunciation information delivered from the eNB 65. Specifically, the UE 45
may detect that the location regis tration area has changed when the location
registration area delivered from the eNB 55 before movement and the location
registration area delivered from the eNB 65 after movement are different from
each other.
9
[0029]
Next, the eNB 65 transfers a Tracking Area Update Request message to the
new MME 35 that manages the location registration area including the
communicat ion area of its own device (S22). At the same t ime, S1 Connect ion
(S1 bearer) is established between the eNB 65 and the new MME 35 fo5 r
communicat ion of a control message between the UE 45 and the new MME 35.
The Tracking Area Update Request message may contain the identifier of the old
MME 25 that used to manage the location registration area from which the UE 45
has moved, or GUTI (Globally Unique Temporary Ident ifier) that is temporarily
10 assigned to the UE 45 by the old MME 25.
[0030]
Then, the new MME 35 sends a Context Request message to the old MME
25 in order to retrieve the user information of the UE 45 from the old MME 25
(S23). The user information may be the location registration information of the
15 UE 45, bearer context and the like, for example. Further, when the Tracking Area
Update Request message contains GUTI, the new MME 35 may specify the address
information of the old MME 25 by using the GUTI.
[0031]
The old MME 25 receives, from the new MME 35, a Context Request
20 message requesting the transfer of the user information of the UE 45. By
receiving the Context Request message sent from the new MME 35, the old MME
25 can detect that the UE 45 has moved out of the location registration area
managed by itself. Further, by receiving the Context Request message sent from
the new MME 35, the old MME 25 can detect that the UE 45 has moved to the
25 location registration area managed by the new MME 35.
[0032]
The old MME 25 sends a Context Response message to the new MME 35 as
a response message to the Context Request message in Step S23 (S24). Using the
Context Response message, the old MME 25 notifies the user information of the
30 UE 45 to the new MME 35.
[0033]
It is assumed that, after the Context Response message is sent from the old
MME 25 to the new MME 35 in Step S24, a control signal notification message is
sent from the PGW 75 to the old MME 25 via the old SGW 15 (S25). The cont rol
10
signal notification message is used to notify the PGW 75 activation control signal
to the MME.
[0034]
The old MME 25 has detected that the UE 45 is during its movement by
receiving the Context Request message in Step S23. Therefore, the old MME 25 5
sends, to the PGW 75, a response signal notificat ion message to which Cause
indicating that the UE 45 is moving and a call attempt to the UE 45 is temporarily
unavai lable is set . The old MME 25 sends the response signal notificat ion
message to the PGW 75 via the old SGW 15 as a response to the control signal
10 notification message (S26). To the response signal not ification message,
"Cause= Temporarily Rejected due to mobility procedure in Progress" is set as
Cause sett ing. "Cause= Temporarily Rejected due to mobi lity procedure in
Progress" indicates that information indicating that the UE is moving and a call
attempt is temporarily rejected is set to Cause.
15 [0035]
Receiving response signal notification message to which "Cause=
Temporarily Rejected due to mobility procedure in Progress " is set, the PGW 75
starts a locally configured guard timer for resending the control signal notification
message.
20 [0036]
Then, the new MME 35 sends a Context Acknowledge message to the old
MME 25 as a response message to the Context Response message (S27). SGW
change indication is set to the Context Acknowledge message. SGW change
indication is informat ion indicat ing that the new MME 35 has changed the SGW
25 for sending data to the UE 45 from the to old MME 25 to the new MME 35 .
[0037]
Then, the new MME 35 sends a Create Session Request message to the new
SGW 85 in order to establ ish a session with the new SGW 85 or to activate a bearer.
The new SGW 85 then sends a Modify Bearer Request message to the PGW 75 in
30 order to establ ish or update a session or a bearer with the PGW 75 (S29). By
receiving the Modify Bearer Request message, the PGW 75 can recognize that
mobility procedure for the UE 45 has completed in the new MME 35. The PGW
75 updates the bearer context between the new SGW 85 and the PGW 75. Further,
the PGW 75 sends a Modify Bearer Response message to the new SGW 85 as a
11
response message to the Modify Bearer Request message (S30). At this time, the
PGW 75 may stop the locally configured guard timer started when rec eiving the
response signal notification message in Step S26.
[0038]
Then, the new SGW 85 updates the bearer context between the new MM5 E
35 and the new SGW 85. Further, the new SGW 85 sends a Create Session
Response message to the new MME 35 as a response message to the Create Session
Request message (S31).
[0039]
10 The old MME 25 and the new MME 35 perform location information
change processing A for the movement of the UE 45. The details of the location
information change processing A are described later .
[0040]
When the locat ion information update processing A ends, the new MME 35
15 sends a Tracking Area Update Accept message to the eNB 65 as a response
message in Step S22. Further, the eNB 65 sends the sent Tracking Area Update
Accept message to the UE 45 (S32).
[0041]
The Tracking Area Update Accept message contains GUTI assigned to the
20 UE 45 by the new MME 35. The GUTI is an ident ifier that is temporarily
assigned to the UE by the new MME 35 in order to uniquely identify the UE.
[0042]
When the Tracking Area Update Accept message contains GUTI, the UE
45 sends a Tracking Area Update Complete message to the new MME 35 (S33).
25 [0043]
After that, the new MME 35 releases the S1 Connection that has been
established between the eNB 65 and the MME 35 (S34).
[0044]
Then, the PGW 75 sends a control signal notification message to the new
30 MME 35 that manages the location registration area to which the UE 45 moves in
order to notify a control signal to the UE 45 (S35). Thus, in Step S35, the
processing of sending the control signal notificat ion message to the old MME 25 in
Step S25 is performed for the new MME 35 that manages the location registration
area to which the UE 45 moves. Then, the new MME 35 sends a Paging message
12
to the eNB 65 in order to perform a call attempt to the UE 45 (S36). Further, the
eNB 65 sends a Paging message to the UE located in the communication area under
its control (S37). When sending the Paging message, the new MME 35 sets GUTI
assigned to the UE 45. In this manner, after movin g to a new location registration
area, the UE 45 can receive the control signal notification message that has bee5 n
made during the movement of the UE 45.
[0045]
In the case where the locally configured guard timer that is started when
the response signal notification message is received in Step S26 expires before
10 receiving the Modify Bearer Request message, the PGW 75 may end the control
message notificat ion processing to the UE45. Alternatively, the PGW 75 may
send the control signal notification message to the old MME 25 again to continue
the control signal not ification processing.
[0046]
15 The location information update processing A is described hereinafter in
detail with reference to Fig. 4. When the new MME 35 receives the Create
Session Response message in Step S31 of Fig. 3, it sends an Update Location
message to the HSS (S201). The HSS is a node device that manages subscriber
information of the UE 45. To the Create Session Response, informat ion
20 indicating that the new MME 35 manages the location information about the UE 45
is set.
[0047]
Then, the HSS sends a Cancel Location message to the old MME 25 so as
to delete the location information about the UE 45 (S202). As a response
25 message to the Cancel Location message, the old MME 25 sends a Cance l Location
ACK message to the HSS (S203). The HSS then sends an Update Location ACK
message to the new MME 35 as a response to the Update Locat ion message in Step
S201 (S204).
[0048]
30 Further, after sending the Cancel Location ACK message, the old MME 25
sends a Delete Session Request message to the old SGW 15 (S205). By sending
the Delete Session Request message, the old MME 25 releases the communication
resource (e.g. EPS bearer resource etc.) wi th the old SGW 15. As a response
message to the Delete Session Request message, the old SGW 15 sends a Delete
13
Session Response message to the old SGW 15 (S206).
[0049]
As described above, with use of the communication system according to
the first exemplary embodiment of the present invention, the following eff ects can
be obtained. Even when the PGW 75 act ivation control signal is made to the U5 E
45 while the UE 45 is during its movement which involves a change in the MME
and the processing for movement of the UE 45 is not completed in a new MME, the
UE 45 can normal ly receive the control signal.
[0050]
10 Further, in the case where the old MME 25 and the new MME 35 are
replaced by the SGSN and the eNB 55 and the eNB 65 are replaced by the RNC, the
Tracking Area Update Request message in Steps S21 and S22 is replac ed by a
Routing Area Update Request message. Further, the Tracking Area Update
Accept message in Steps S32 and S2 is replaced by a Routing Area Update Accept
15 message.
[0051]
Although the flow of processing when the control signal notification
message is sent to the old MME 25 after Step S24 is shown in the figure, the same
processing as in this figure is performed also when the control signal notification
20 message is sent to the old MME 25 during a period after Step S23 and before Step
S29.
[0052]
Further, specific examples of the PGW 75 activation control signal sent
from the PGW 75 are EPC(LTE):Create Bearer Request , EPC(LTE):Update Bearer
25 Request , EPC(LTE):Delete Bearer Request, GPRS(2G/3G):Update PDP Context
Request , GPRS(2G/3G):PDU Notification Reques t , GPRS(2G/3G):Delete PDP
Context Request, and GPRS(2G/3G): Initiate PDP Context Act ivation Request .
[0053]
[Second exemplary embodiment]
30 A processing sequence in a communication system according to a second
exemplary embodiment of the present invention i s described hereinafter with
reference to Fig. 5. Processing when an incoming packet call is made to the new
MME 35 that manages the location information of the UE 45 after movement is
shown in this figure. It is assumed that the MME change processing for the
14
movement of the UE 45 is not completed when the new MME 35 receives a
message related to an incoming packet call or a PGW 75 activation control signal.
To be specific, it is assumed that the UE 45 does not receive a response message to
the Tracking Update Request message when the new MME 35 receives a message
related to an incoming packet call or a PGW 75 act ivation control signal5 .
[0054]
Steps S41 to S49 are the same as Steps S21 to S24 and Steps S27 to S31 in
Fig. 3, and therefore detailed explanation thereof is omitted. Further, location
information update processing A that is performed after Step S49 is the same as the
10 location information update processing A in Fig. 3, and therefore detailed
explanation thereof is omitted.
[0055]
In Step S46, the new SGW 85 receives a Create Session Request message,
and it recognizes that the new MME 35 is managing the user information about the
15 UE 45. Further, in Step S47, the PGW 75 receives a Modify Bearer Request
message and recognizes that the new SGW 85 is managing the session or the bearer
context about the UE 45. Therefore, in Step S50, when an incoming packet call
or a PGW 75 activat ion control signal for the UE 45 is made, the PGW 75 sends the
incoming packet call or a message about the PGW 75 activa tion control signal to
20 the new SGW 85.
[0056]
Then, the new SGW 85 sends a Downlink Data Notification message
indicating that an incoming packet call is made to the UE 45 or the PGW 75
activation control signal to the new MME 35 (S51).
25 [0057]
Then, when the new MME 35 receives the Update Location ACK message
in Step S204 of the location information update processing A shown in Fig. 4, it
sends a Tracking Area Update Accept message to the UE 45 via the eNB 65 (S52).
Note that , after sending a Create Session Request message to the new SGW 85 in
30 Step S46, the new MME 35 receives a Downlink Data Notification message that
requires paging processing for the UE 45. In this case, a user plane setup
procedure is activated in conjunction with a Tracking Area Updat e Accept message.
When, in Steps S41 and S42, an active flag is set , and even when an active flag is
not set, the user plane setup procedure is activated.
15
[0058]
The user plane setup procedure in conjunction with a Tracking Area
Update Accept message is described hereinafter. The new MME 35 sends an
S1-AP Initial Context Setup Request message together with the Tracking Area
Update Accept message in Step S52 to the eNB 65. In other words, the new MM5 E
35 sends the Tracking Area Update Accept message and t he S1-AP Ini tial Context
Setup Request message at the same timing to the eNB 65. Triggered by the S1 -AP
Initial Context Setup Request message, Radio Bearer Establishment (S54) takes
place between the eNB 65 and the UE 45. To notify the newly established bearer
10 information, the eNB 65 sends an S1 AP Initial Context Setup Response message
to the new MME 35 (S56). The new MME 35 sends a Modify Bearer request
message to the new SGW 85 (S57). The new SGW 85 sends a Modify Bearer
response message to the new MME 35 (S58). The user plane setup procedure is to
set the communication resource for transferring data to be sent and received by the
15 UE 45 in the eNB 65, the new SGW 85 and the PGW 75, for example.
[0059]
Further, the Tracking Area Update Accept contains GUTI that is assigned
to the UE 45 by the new MME 35. The GUTI is an ident ifier that is temporarily
assigned to the UE by the new MME 35 in order to uniquely identify the UE.
20 When the UE 45 receives the Tracking Area Update Accept message that contains
the GUTI, it sends a Tracking Area Update Complete message to the new MME 35
(S55).
[0060]
Steps S53 to S58 indicate that, during execution of the Tracking Area
25 Update processing, incoming packet call processing or control signal reception
processing continues using an RRC connection that is already established between
the UE 45 and the new MME 35.
[0061]
Further, a flow of the processing in the case where the Downl ink Data
30 Notification message is sent to the new MME 35 during execution of the Tracking
Area Update processing is described in this figure. On the other hand, when the
control signal notification message is sent to the new MME 35, which is described
in Fig. 3, the same processing as in the case where the Downlink Data Notificat ion
message is sent to the new MME 35 is performed.
16
[0062]
Further, a flow of the processing when an incoming packet call in Step S50
is made after Step S49 and the location information update processing A is
described in this figure. Note that , however, an incoming pa cket call in Step S50
can be made at anytime between Step S47 to Step S52. In this case also, the sam5 e
processing as described in this figure is performed.
[0063]
Further, although an example of using the new MME 35 is described in this
figure, an SGSN may be used instead of the new MME 35. In the figures
10 described hereinafter also, an SGSN may be used instead of the new MME 35.
[0064]
As described above, the new MME 35 adds GUTI that is temporari ly
assigned to the UE 45 to the Tracking Area Update Acce pt message and thereby
notifies the GUTI to the UE 45. Therefore, the new MME 35 can perform Paging
15 processing to the UE 45 and call the UE 45 immediately after completion of the
Tracking Area Update processing.
[0065]
Further, when the new MME 35 receives the Downlink Data Notificat ion
message, it activates the user plane setup procedure in conjunction with the
20 Tracking Area Update Accept message. It is thereby possible to send Downlink
Data to the UE 45. In other words, by sending the S1 -AP Initial Context Setup
Request message in conjunction with the Tracking Area Update Accept message to
the eNB 65, it is possible to establish Radio Bearer between the UE 45 and the eNB
65 during execution of the Tracking Area Update processing. Therefore, the new
25 MME 35 can identify the UE 45 and send data to the UE 45 without performing
Page processing.
[0066]
(Modified examples)
Modified examples of the processing sequence of Fig. 5 are described
30 hereinbelow. First, a processing sequence in a modified example of the
processing according to the second exemplary embodiment of the invention is
described with reference to Fig. 6. In this figure, a flow of the processing in the
case where, when the UE 45 moves, the MME that manages the UE 45 is changed
from the old MME 25 to the new MME 35 but the SGW is not changed from the old
17
SGW 15 is described.
[0067]
Steps S61 to S65 are the same as Steps S41 to S45 in Fig. 5, and therefore
detailed explanation thereof is omitted. By the movement of the UE 45, the MME
that manages the UE 45 has changed from the old MME 25 to the new MME 355 .
Therefore, the new MME 35 uses the bearer context received from the old MME 25
as the EPS (Evolved Packet System) bearer context of the UE 45. The EPS is a
communicat ion system that is specified in the 3GPP. Note that the old SGW 15 is
not changed for the UE 45. Thus, to change the informat ion about the UE 45 that
10 is held by the old SGW 15, the new MME 35 sends a Modify Bearer Request
message to the old SGW 15 in Step S66.
[0068]
Steps S67 and S68 are different from Steps S47 and S48 in Fig. 5 in that
the PGW 75 communicates with the old SGW 15 instead of the new SGW 85;
15 however, messages to be sent and received are the same as those in Steps S47 and
S48, and therefore detailed explanation thereof is omitted.
[0069]
The old SGW 15 receives a Modify Bearer Response message in Step S68,
and then updates the bearer context with the new MME 35 and sends a Modify
20 Bearer Response to the new MME 35 (S69).
[0070]
Processing after the location information update processing A is the same
as processing after the location information update processing A in Fig. 5, and
detailed explanation thereof is omitted. Further, Step S70 is different from Step
25 S50 in Fig. 5 in that the PGW 75 communicates with the old SGW 15 instead of the
new SGW 85. Further, Step S71 is different from Step S51 in Fig. 5 in that the
new MME 35 communicates with the old SGW 15 instead of the new SGW 85.
Further, Steps S77 and S78 are different from Steps S57 and S58 in Fig. 5 in that
the Modify Bearer Request/Response message is sent and received between the
30 new MME 35 and the old SGW 15. Steps S70 to S78 are the same as Steps S50 to
S58 in Fig. 5 in the other points , and detai led explanation thereof is omi tted.
[0071]
A flow of processing in the case where the SGSN is used instead of the
new MME 35 and the RNC is used instead of the eNB 65 in Fig. 5 is described
18
hereinafter with reference to Fig. 7. Differences from Fig. 5 are mainly described
below.
[0072]
In Step S81, the UE 45 sends a Routing Area Update Request message,
instead of the Tracking Area Update Request message in Step S41 of Fig. 5, to th5 e
RNC. Further, in Step S82, the RNC transfers the Routing Area Update Request
message to the SGSN. Steps S83 to S91 are the same as Steps S43 to S51 of Fig.
5, and detailed explanation thereof is omit ted.
[0073]
10 In Step S92, the SGSN sends a Routing Area Update Accept message
instead of the Tracking Area Update Accept message in Step S51 of Fig. 5. When
the SGSN receives, in Step S91, a Downlink Data Notification message or a PGW
75 activation control signal that requires Paging processing to the UE 45, it sends a
Routing Area Update Accept message to which a value "fol low-on proceed" is set
15 to an Update result parameter. The UE 45 receives the Routing Area Update
Accept message and reuses the RRC connection that is established between the
SGSN and the UE 45 without releasing it . The SGSN sets the value "follow-on
proceed " to the Rout ing Area Update Accept message and t hereby prompts the UE
45 to send a Service Request message. The UE 45 thereby sends the Service
20 Request message to the SGSN by reusing the RRC connection that is held for the
SGSN as a response to Page.
[0074]
The Routing Area Update Accept message conta ins P-TMSI
(Packet -Temporary Mobile Subscriber Identity). The P-TMSI is an identifier that
25 is temporarily assigned to the UE 45 by the SGSN. The P-TMSI corresponds to
the GUTI, which is an identifier that is temporarily assigned to the UE by the
MME.
[0075]
Then, the UE 45 sends a Routing Area Update Complete message to the
30 SGSN (S93). The UE 45 then sends, to the SGSN, a Service Request message to
which the P-TMSI is set (S94).
[0076]
When the SGSN receives the Service Request message sent from the UE 45,
it sends an RAB Assignment Request message to the RNC to request the
19
establishment of a radio access bearer (S95). The RNC establ ishes the radio
access bearer and sends an RAB Assignment Response message to the SGSN (S96).
[0077]
A flow of processing in the case where the SGW is not changed when the
UE 45 moves is described wi th reference to Fig. 8. Differences from Fig. 7 ar5 e
mainly described.
[0078]
Steps S101 to S105 are the same as Steps S81 to S85 in Fig. 7, and detailed
explanation thereof is omitted. In Step S106, the SGSN sends a Modify Bearer
10 Request message to the old SGW 15 (S106). Steps S107 and S108 are the same as
Steps S87 and S88 in Fig. 7. As a response to the Modify Bearer Request
message, the old SGW 15 sends a Modify Bearer Response message to the SGSN.
Processing after the location information update processing A is the same as
processing after the location information update processing A in Fig. 7, and
15 detailed explanation thereof is omitted.
[0079]
In Figs. 5 and 6 described above, a processing flow in the case where,
when the MME that manages the UE 45 is changed with the movement of the UE
45 from an LTE communication area to an LTE communication area, a Downlink
20 Notification message or a PGW 75 activation control sig nal is sent to the new
MME 35, which is the MME after change, is described. Further, in Figs. 7 and 8,
a processing flow in the case where, when the node device that manages the UE 45
is changed from the MME to the SGSN with the movement of the UE 45 from an
LTE communication area to a 3G communication area, a Downl ink Notification
25 message or a PGW 75 activation control signal is sent to the SGSN is described.
[0080]
In addit ion to the examples of movement described in Figs. 5 to 8, there is
also a case where the UE 45 moves from a 3G communication area to a 3G
communicat ion area. In this case, the node device that manages the UE 45 is
30 changed from an old SGSN to a new SGSN in some cases. When the node device
that manages the UE 45 is changed from an old SGSN to a new SGSN, an SGSN
Context Request message, an SGSN Context Response message and an SGSN
Context Acknowledge message are used between the old SGSN and the new SGSN,
instead of the Context Request message, the Context Response message and the
20
Context Acknowledge message in Steps S103 to S105 in Fig. 8.
[0081]
Further, when the node device that manages the UE 45 is changed from an
old SGSN to a new SGSN, an Update PDP Context Request message is used instead
of the Modify Bearer Request message in Steps S106 and S107 in Fig. 8, and a5 n
Update PDP Context Response message is used instead of the Modify Bearer
Response in Steps S108 and S109 in Fig. 8, respectively between the new SGSN
and a GGSN.
[0082]
10 Further, in the case where the UE 45 moves betwee n a 3G communication
area and a 2G communication area also, the same processing as in the case where
the node device that manages the UE 45 is changed from an old SGSN to a new
SGSN is performed.
[0083]
15 By performing the processing sequences described in Figs. 5 to 8, it is
possible to send data to the UE 45 even when an incoming packet call is made or a
PGW 75 activation control signal is received during the Tracking Area Update
processing or the Routing Area Update processing just l ike in Figs. 3 and 4.
[0084]
20 [Third exemplary embodiment]
Paging processing to the UE 45 in a communication system according to a
third exemplary embodiment of the present invention is described hereinafter. In
the third exemplary embodiment , when the Tracking Area Update processing or the
Routing Area Update processing is done, the new MME 35 or the SGSN performs
25 Paging processing to the UE 45
[0085]
To be specific, in the processing sequences of Figs. 5 and 6, the new MME
35 holds the Downlink Data Notification message rec eived in Step S51 or Step S71
in a memory or the l ike of the device. After that , when the new MME 35 receives
30 the Tracking Area Update Complete message in Step S53 or S73, it performs
Paging processing to the UE 45 in accordance with the held Downlink Dat a
Notification message.
[0086]
Further, in the processing sequences of Figs. 7 and 8, the SGSN holds the
21
Downlink Data Notification message received in Step S91 or Step S111 in a
memory or the like of the device. After that, when the SGSN receives the RAB
Assignment Response message in Step S96 or S116, it performs Paging processing
to the UE 45 in accordance with the held Downlink Data Notification message.
[00875 ]
As described above, by performing Paging processing according to the
third exemplary embodiment of the invent ion, i t is possible to perform Paging
processing to the UE 45 in accordance wi th the held Downlink Data Notification
message without wait ing for the Downlink Data Notification to be sent again. It
10 is thereby possible to reduce the numbe r of signals between the SGW and the MME
and advance the timing to perform Paging processing to the UE 45.
[0088]
Although the present invention is described as a hardware configuration in
the above exemplary embodiments, the present invention is not limi ted thereto.
15 The present invention may be implemented by causing a CPU (Central Processing
Unit) to execute a computer program to perform the processing in each node
device.
[0089]
In the above example, the program can be stored and provided to the
20 computer using any type of non-transitory computer readable medium. The
non-transitory computer readable medium includes any type of tangible storage
medium. Examples of the non-transi tory computer readable medium include
magnetic storage media (such as floppy disks, magnetic tapes, hard disk drives,
etc.), optical magnetic storage media (e.g. magneto-optical disks), CD-ROM (Read
25 Only Memory), CD-R , CD-R/W, and semiconductor memories (such as mask ROM,
PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM
(Random Access Memory), etc.). The program may be provided to a computer
using any type of transitory computer readable medium. Examples of the transi tory
computer readable medium include electric signals, opt ical signals, and
30 electromagnetic waves. The transitory computer readable medium can provide the
program to a computer via a wired communication line such as an electric wire or
optical fiber or a wireless communication line.
[0090]
It should be noted that the present invention is not limited to t he
22
above-described exemplary embodiment and may be varied in many ways within
the scope of the present invention.
[0091]
While the invention has been particularly shown and described with
reference to exemplary embodiments thereof, the invention is not limited to thes5 e
embodiments. It will be understood by those of ordinary skil l in the art that various
changes in form and details may be made therein without departing from the spirit
and scope of the present invention as defined by the claims.
[0092]
10 This applicat ion is based upon and claims the benefit of priority from
Japanese patent application No. 2014-098247 filed on May 12, 2014, the disclosure
of which is incorporated herein in its entirety by reference.
[0093]
For example, the whole or part of the exemplary embodiments disclosed
15 above can be described as, but not limi ted to, the following supplementary notes.
[0094]
(Supplementary note 1)
A communication system including an MME that, by movement of a UE,
performs Tracking Area Update processing that changes a locat ion registration
20 area of the UE and manages the location registration area of the UE before change,
and a PGW that sends, to the MME, a control signal required to be not ified to the
UE during execut ion of the Tracking Area Update process ing, wherein the MME
receives the control signal, and sends a response signal indicating that the
Tracking Area Update processing is being executed to the PGW, and after
25 completion of the Tracking Area Update processing, the PGW sends the control
signal to an MME that manages the location registration area of the UE after
change.
(Supplementary note 2)
A communication system including an MME that, by movement of a UE,
30 performs Tracking Area Update processing that changes a locat ion registration
area of the UE and manages the location registration area of the UE after change,
and an SGW that notifies a Downlink Data Notification message to the MME
during execution of the Tracking Area Update processing, wherein the MME
receives the Downlink Data Notification message, and activates a user plane setup
23
procedure in conjunction with a Tracking Area Update Accept message to be sent
to the UE.
(Supplementary note 3)
A communication system including an MME that, by movement of a UE,
performs Tracking Area Update processing that changes a locat ion registratio5 n
area of the UE and manages the location registration area of the UE after change,
and an SGW that notifies a Downlink Data Notification message to the MME
during execution of the Tracking Area Update processi ng, wherein the MME sends
a Tracking Area Update Accept message to the UE after holding the Downlink
10 Data Notification message, receives a Tracking Area Update Complete message
from the UE, and then performs paging processing to the UE in accordance with
the Downlink Data Notification message.
(Supplementary note 4)
An MME that, by movement of a UE, performs Tracking Area Update
15 processing that changes a location registrat ion area of the UE and manages the
location registration area of the UE before change, wherein the MME receives a
control signal sent from a PGW and required to be notified to the UE during
execution of the Tracking Area Update processing, and in response to receiving the
control signal, sends a response signal indicating that the Trackin g Area Update
20 processing is being executed to the PGW, and, after complet ion of the Tracking
Area Update processing, causes the PGW to send the control signal to an MME that
manages the location registration area of the UE after change.
(Supplementary note 5)
An MME that, by movement of a UE, performs Tracking Area Update
25 processing that changes a location registrat ion area of the UE and manages the
location registration area of the UE after change, wherein the MME receives a
Downlink Data Notification message sent from an SGW during execution of the
Tracking Area Update processing, and in response to receiving the Downlink Data
Notification, activates a user plane setup procedure in conjunction with a Tracking
30 Area Update Accept message to be sent to the UE.
An MME that, by movement of a UE, performs Tracking Area Update
processing that changes a location registrat ion area of the UE and manages the
location registration area of the UE after change, wherein the MME receives a
Downlink Data Notification mes sage sent from an SGW during execution of the
24
Tracking Area Update processing, and after holding the Downl ink Data
Notification message, sends a Tracking Area Update Accept message to the UE,
receives a Tracking Area Update Complete message from the UE, an d then
performs paging processing to the UE in accordance with the Downlink Data
Notification message5 .
(Supplementary note 7)
A communication method in an MME that, by movement of a UE, performs
Tracking Area Update processing that changes a location reg istrat ion area of the
UE and manages the location registrat ion area of the UE before change, the method
10 including receiving a control signal sent from a PGW and required to be notified to
the UE during execut ion of the Tracking Area Update processing, in r esponse to
receiving the control signal, sending a response signal indicat ing that the Tracking
Area Update processing is being executed to the PGW, and after completion of the
Tracking Area Update processing, causing the PGW to send the control signal to an
15 MME that manages the location registration area of the UE after change.
Reference Signs List
[0095]
10 BEARER MANAGEMENT DEVICE
11 INCOMING CALL CONTROL UNIT
20 15 OLD SGW
16 INCOMING CALL CONTROL UNIT
17 DATA ACCUMULATION UNIT
20 MOBILITY MANAGEMENT DEVICE
21 LOCATION REGISTRATION AREA
25 25 OLD MME
30 MOBILITY MANAGEMENT DEVICE
31 LOCATION REGISTRATION AREA
35 NEW MME
40 MOBILE TERMINAL DEVICE
30 45 UE
55 eNB
65 eNB
75 PGW
85 NEW SGW
25

WE CLAIM:
1. A method for a mobile communication system, the method comprising:
initiating a TAU (Tracking Area Update) procedure with MME (Mobility
Management Enti ty) change or an RAU (Routing Area Update) procedure wit5 h
SGSN (Serving GPRS Support Node) change; and
activating a user plane setup procedure if a new MME or a new SGSN
receives a DDN (Downlink Data Notification) message while a UE (User
Equipment) is connected to the new MME or the new SGSN in the TAU procedure
10 or the RAU procedure.
2. The method according to Claim 1, wherein
the DDN message is sent to page the UE from an SGW (Serving Gateway)
to the new MME or the new SGSN.
15
3. The method according to Claim 1 or 2, wherein
the user plane setup procedure is activated even if an active flag is not set
in a TAU request message in the TAU procedure or an RAU request message in the
RAU procedure.
20
4. The method according to any one of Claims 1 to 3, wherein
the user plane setup procedure is activated in conjunction with a TAU
accept message in the TAU procedure or an RAU accept message in the RAU
procedure.
25
5. A method for a mobile communication system, the method comprising:
initiating, by a UE (User Equipment), a TAU (Tracking Area Update)
procedure with MME (Mobility Management Entity) change or an RAU (Routing
Area Update) procedure with SGSN (Serving GPRS Support Node) change; and
30 sending, by an old MME or an old SGSN, a signal including information
that a PGW (Packet Data Network Gateway) initiated signal is temporarily rejected
due to mobili ty procedure in progress to the PGW via an SGW (Servi ng Gateway)
if the old MME or the old SGSN receives the PGW initiated signal during the TAU
procedure or the RAU procedure.
26
6. The method according to Claim 5, further comprising:
upon reception of the signal, starting a locally configured guard timer b y
the PGW.
5
7. A mobile communication system comprising:
a UE (User Equipment); and
a plurality of MMEs (Mobility Management Entities) or a plurality of
SGSNs (Serving GPRS Support Nodes);
10 wherein the UE initiates a TAU (Tracking Area Update) procedure with
MME change or an RAU (Routing Area Update) procedure with SGSN change, and
wherein a user plane setup procedure is activated if a new MME or a new
SGSN receives a DDN (Downlink Data Notification) message while the UE is
connected to the new MME or the new SGSN in the TAU procedure or the RAU
15 procedure.
8. The mobile communication system according to Claim 7, wherein
the DDN message is sent to page the UE from an SGW (Serving Gateway)
to the new MME or the new SGSN.
20
9. The mobile communication system according to Claim 7 or 8, wherein
the user plane setup procedure is activated even if an active flag is not set
in a TAU request message in the TAU procedure or an RAU request message in the
RAU procedure.
25
10. The mobile communication system according to any one of Claims 7 to
9, wherein
the user plane setup procedure is activated in conjunction with a TAU
accept message in the TAU procedure or an RAU accept message in the RAU
30 procedure.
11. A mobile communication system comprising:
a UE (User Equipment);
a plurality of MMEs (Mobility Management Entities) or a plurality of
27
SGSNs (Serving GPRS Support Nodes);
an SGW (Serving Gateway); and
a PGW (Packet Data Network Gateway),
wherein the UE initiates a TAU (Tracking Area Update) procedure with
MME change or an RAU (Routing Area Update) procedure with SGSN change, an5 d
wherein an old MME or an old SGSN sends a signal including
information that a PGW initiated signal is temporarily rejected due to mobili ty
procedure in progress to the PGW via the SGW if the old MME or the old SGSN
receives the PGW ini tiated signal during the TAU procedure or the RAU
10 procedure.
12. The mobile communication system according to Claim 11, wherein
upon reception of the signal, the PGW starts a locally configured guard
timer.
15
13. A mobile terminal used in a mobile communicat ion system, the mobile
terminal comprising:
means for initiating a TAU (Tracking Area Update) procedure with MME
(Mobility Management Entity) change or an RAU (Routing Area Update)
20 procedure with SGSN (Serving GPRS Support Node) change,
wherein the mobile terminal causes a user plane setup procedure to
activate if a new MME or a new SGSN receives a DDN (Downlink Data
Notification) message while the mobi le terminal is connected to the new MME or
the new SGSN in the TAU procedure or the RAU procedure.
25
14. The mobile terminal according to Claim 13, wherein
the DDN message is sent to page the mobi le terminal from an SGW
(Serving Gateway) to the new MME or the new SGSN.
30 15. The mobile terminal according to Claim 13 or 14, wherein
the user plane setup procedure is activated even if an active flag is not set
in a TAU request message in the TAU procedure or an RAU request message in the
RAU procedure.
28
16. The mobile terminal according to any one of Claims 13 to 15, wherein
the user plane setup procedure is activated in conjunction with a TAU
accept message in the TAU procedure or an RAU accept message in the RAU
procedure.
5
17. A network node for a mobile communication system including an SGW
(Serving Gateway) and a PGW (Packet Data Network Gateway) , the network node
comprising:
managing means for managing a UE (User Equipment); and
10 reception means for receiving an area update request from the UE via a
base stat ion in an area update procedur e,
wherein the network node sends a signal including information that a PGW
initiated signal is temporarily rejected due to mobility procedure in progress to the
PGW via the SGW if the network node receives the PGW initiated signal during
15 the area update procedure with change of the network node initiated by the UE.
18. The network node according to Claim 17, wherein
the network node is an MME (Mobi lity Management Ent ity) or an SGSN
(Serving GPRS Support Node).
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19. The network node according to Claim 17 or 18, wherein
the area update request is a TAU (Tracking Area Update) request or an
RAU (Routing Area Update) request, and
the area update procedure is a TAU procedure or an RAU procedure.
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20. A PGW (Packet Data Network Gateway) for a mobile commun ication
system, the PGW comprising:
means for connect ing to an external network,
wherein the PGW receives a signal including information that a PGW
30 initiated signal is temporarily rejected due to mobility procedure in progress from
an old MME (Mobili ty Management Entity) or an old SGSN (Serving GPRS
Support Node) via a SGW (Serving Gateway) if the old MME or the old SGSN
receives the PGW ini tiated signal during a TAU (Tracking Area Update) procedure
with MME change or an RAU (Routing Area Update) procedur e with SGSN change
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initiated by a UE (User Equipment), and
wherein the PGW starts a locally configured guard timer.