U.S. patent application number 13/398253 was filed with the patent office on 2012-08-23 for communication system and communication controlling method.
This patent application is currently assigned to NEC EUROPE LTD.. Invention is credited to Gottfried PUNZ, Stefan SCHMID, Tarik TALEB, Toshiyuki TAMURA, Hajime ZEMBUTSU.
Application Number | 20120213199 13/398253 |
Document ID | / |
Family ID | 43758772 |
Filed Date | 2012-08-23 |
United States Patent
Application |
20120213199 |
Kind Code |
A1 |
ZEMBUTSU; Hajime ; et
al. |
August 23, 2012 |
COMMUNICATION SYSTEM AND COMMUNICATION CONTROLLING METHOD
Abstract
A communication method in LIPA/SIPTO architecture is provided
which, when a user equipment (UE) is to connect from a serving area
to an external network, allows re-selection of an optimal gateway.
The communication method allows selecting a gateway apparatus
physically or topologically close to a site, where the user
equipment is attached.
Inventors: |
ZEMBUTSU; Hajime; (Tokyo,
JP) ; TAMURA; Toshiyuki; (Tokyo, JP) ; SCHMID;
Stefan; (Heidelberg, DE) ; TALEB; Tarik;
(Heidelberg, DE) ; PUNZ; Gottfried; (Heidelberg,
DE) |
Assignee: |
NEC EUROPE LTD.
Heidelberg
DE
NEC CORPORATION
Tokyo
JP
|
Family ID: |
43758772 |
Appl. No.: |
13/398253 |
Filed: |
February 16, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13118743 |
May 31, 2011 |
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13398253 |
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13149264 |
May 31, 2011 |
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13118743 |
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13131810 |
Aug 8, 2011 |
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PCT/JP2010/066211 |
Sep 17, 2010 |
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13149264 |
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Current U.S.
Class: |
370/331 |
Current CPC
Class: |
H04W 76/22 20180201;
H04W 36/12 20130101; H04W 36/32 20130101; H04W 36/0033 20130101;
H04W 76/20 20180201; H04W 40/36 20130101; H04W 36/0061
20130101 |
Class at
Publication: |
370/331 |
International
Class: |
H04W 36/00 20090101
H04W036/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 18, 2009 |
JP |
2009-217757 |
Claims
1. A communication method in Selected IP Traffic Offload (SIPTO)
architecture, the method comprising: a mobility management entity
(MME) sending a first signal for setting re-attachment to a user
equipment, when the MME decides that it is necessary to re-select a
gateway apparatus on receipt of a tracking area (TA) update signal
from the user equipment; the user equipment, on receipt of the
first signal, transmitting a second signal for re-attachment to the
MME; and the MME performing re-selection of a gateway
apparatus.
2. A communication method in Selected IP Traffic Offload (SIPTO)
architecture, the method comprising: a Serving General Packet Radio
Service Support Node (SGSN) sending a first signal for setting
re-attachment to a user equipment, when the SGSN decides that it is
necessary to re-select a gateway apparatus on receipt of a routing
area (RA) update signal from the user equipment; the user
equipment, on receipt of the first signal, transmitting a second
signal for re-attachment to the SGSN; and the SGSN performing
re-selection of a gateway apparatus.
3. The communication method according to claim 1, wherein the
gateway apparatus includes at least one of a serving gateway
apparatus, a packet data network gateway apparatus and a Gateway
General Packet Radio Service Support Node (GGSN).
4. The communication method according to claim 2, wherein the
gateway apparatus includes at least one of a serving gateway
apparatus, a packet data network gateway apparatus and a Gateway
General Packet Radio Service Support Node (GGSN).
5. A communication system in Selected IP Traffic Offload (SIPTO)
architecture, the system comprising: a user equipment; a mobility
management entity (MME); and a plurality of gateway apparatuses,
wherein the MME sends a first signal for setting re-attachment to
the user equipment, when the MME decides that it is necessary to
re-select the gateway apparatus on receipt of a tracking area
update signal from the user equipment; the user equipment, on
receipt of the first signal, transmits a second signal for
re-attachment to the MME; and the MME performs re-selection of the
gateway apparatus.
6. A communication system in Selected IP Traffic Offload (SIPTO)
architecture, the system comprising: a user equipment; a Serving
General Packet Radio Service Support Node (SGSN); and a plurality
of gateway apparatuses, wherein the SGSN sends a first signal for
setting re-attachment to the user equipment, when the SGSN decides
that it is necessary to re-select the gateway apparatus on receipt
of a routing area (RA) update signal from the user equipment; the
user equipment, on receipt of the first signal, transmits a second
signal for re-attachment to the SGSN; and the SGSN performs
re-selection of the gateway apparatus.
7. The communication system according to claim 5, wherein the
gateway apparatus includes at least one of a serving gateway
apparatus, a packet data network gateway apparatus and a Gateway
General Packet Radio Service Support Node (GGSN).
8. The communication system according to claim 6, wherein the
gateway apparatus includes at least one of a serving gateway
apparatus, a packet data network gateway apparatus and a Gateway
General Packet Radio Service Support Node (GGSN).
9. A user equipment in a communication system by Selected IP
Traffic Offload (SIPTO) architecture, wherein the user equipment
transmits a tracking area (TA) update signal to a mobility
management entity (MME) and receives a first signal that sets
re-attachment from the MME, and the user equipment transmits a
second signal for re-attachment to the MME, to cause the MME to
perform re-selection of a gateway apparatus.
10. A user equipment in a communication system by Selected IP
Traffic Offload (SIPTO) architecture, wherein the user equipment
transmits a routing area (RA) update signal to a Serving General
Packet Radio Service Support Node (SGSN) and receives a first
signal that sets re-attachment from the SGSN, and the user
equipment transmits a second signal for re-attachment to the SGSN,
to cause the SGSN to perform re-selection of a gateway
apparatus.
11. The user equipment according to claim 9, wherein the gateway
apparatus includes at least one of a serving gateway apparatus, a
packet data network gateway apparatus, and a Gateway General Packet
Radio Service Support Node (GGSN).
12. The user equipment according to claim 10, wherein the gateway
apparatus includes at least one of a serving gateway apparatus, a
packet data network gateway apparatus, and a Gateway General Packet
Radio Service Support Node (GGSN).
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. Nos. 13/118,743 filed May 31, 2011 and 13/149,264 filed May
31, 2011 which are divisionals of U.S. patent application Ser. No.
13/131,810, filed May 27, 2011 (published), which is a national
stage of International Application No. PCT/JP2010/066211, filed
Sep. 17, 2010, claiming priority based on Japanese Patent
Application No. 2009-217757, filed Sep. 18, 2009, the contents of
all of which are incorporated herein by reference in their
entirety.
TECHNICAL FIELD
[0002] This invention relates to a mobile communication system and,
more particularly, to a system optimal for re-selection of a
gateway that connects a terminal to a packet data network. This
invention also relates to a communication controlling method.
BACKGROUND
[0003] In EPC (Evolved Packet Core), bearer management is performed
based on an `Always On` concept in such a manner that a PGW (PDN
(Packet Data Network) Gateway), initially selected when a UE (User
Equipment or `terminal`) has attached the EPC, is fixedly used as
anchor until the UE detaches. By this manner of operation, it is
possible for a service network (a packet data network) to provide
services premised on permanent connection. It is because the IP
information driven out by the PGW is unchanged even if the UE moves
repeatedly within the EPC.
[0004] When a UE moves within the EPC, an SGW (Serving Gateway) is
re-selected in accompaniment with the movement of the UE. Each time
the SGW is re-selected, a bearer between the SGW and the PGW is
updated by disconnection and re-establishment to ensure
connectivity from the UE to the PGW.
[0005] In general, in selecting a PGW, such a PGW is selected which
is close to the SGW physically or from the perspective of network
topology.
[0006] However, in case the UE performs repeated movement over long
distances or has stayed in a far-away place after such
long-distance movement, the PGW, initially selected, may be far
away from a SGW in terms of a distance(a physical or network
topological distance). As a result, network efficiency is
deteriorated to present problems such as transmission delay of user
data or inefficient consumption of network resources within the
EPC.
[0007] For example, when a passenger to Japan from abroad enters at
Narita International Airport, he/she may usually power-up the
mobile phone apparatus at the International Airport to attach to
EPC. Hence, a PGW located close to Narita International Airport is
selected. However, after entrance to Japan, he/she may move to
e.g., Tokyo, Osaka, Sapporo or Fukuoka. Hence, after each such
movement, the PGW close to the Narita International Airport is no
longer the most efficient PGW.
SUMMARY
[0008] The following is an analysis by the present inventors. In
the EPC network, a default bearer, established at the time of
attachment, is not deleted/ re-established until the time of
detachment under the `Always On` principle. If the bearer is to be
switched due to UE's movement, the PGW, selected at the time of
attachment, remains fixed as anchor.
[0009] Consequently, such a problem is raised that, when a UE moves
over a long distance, maintaining connection to the PGW selected at
the time of the attachment may be inefficient from the perspective
of EPC network.
[0010] Such a system is thus desired that, when a UE moves over a
long distance, and the UE is to connect from a serving area in
which the UE resides to an external network (service network),
allows re-selecting an optimal PGW (result of analysis by the
present inventors).
[0011] It is therefore an object of the present invention to
provide a system and a method, which make it possible to re-select
an optimal gateway node, when a terminal (UE) is to connect from a
serving area to an external network.
[0012] In one aspect of the present invention, there is provided In
one aspect of the present invention, there is provided a
communication method in Local IP Access (LIPA)/Selected IP Traffic
Offload (SIPTO) architecture, wherein a gateway apparatus
physically or topologically close to a site, where the user
equipment is attached, is selected according to movement of the
user equipment.
[0013] According to the present invention, there is provided a
communication system in Local IP Access (LIPA)/Selected IP Traffic
Offload (SIPTO) architecture, wherein a gateway apparatus
physically or topologically close to a site, where the user
equipment is attached, is selected, according to movement of the
user equipment.
[0014] According to the present invention, there is provided user
equipment in a communication system by Local IP Access
(LIPA)/Selected IP Traffic Offload (SIPTO) architecture, wherein a
gateway apparatus physically or topologically close to a site,
where the user equipment is attached, is selected, according to
movement of the user equipment.
[0015] In another aspect of the present invention, there is
provided a communication method in Local IP Access (LIPA)/Selected
IP Traffic Offload (SIPTO) architecture, wherein, in case a
mobility management entity (MME) decides that it is necessary to
re-select a gateway apparatus, the MME sends a first signal for
setting re-attachment to a user equipment, the user equipment on
receipt of the first signal transmitting a second signal for
re-attachment to the MME and the MME re-selecting the gateway
apparatus. There is also provided a communication method in
Selected IP Traffic Offload (SIPTO) architecture, wherein a
mobility management entity (MME) sends a first signal for setting
re-attachment to a user equipment, when the MME decides that it is
necessary to re-select a gateway apparatus; the user equipment, on
receipt of the first signal, transmits a second signal for
re-attachment to the MME; and the MME, based on a delete session
response that is received by a serving gateway apparatus connected
to the MME from a packet data network gateway apparatus, performs
re-selection of a packet data network gateway apparatus.
[0016] According to the present invention, there is provided a
communication system in Local IP Access (LIPA)/Selected IP Traffic
Offload (SIPTO) architecture, comprising a mobility management
entity (MME) and a user equipment, wherein the MME sends a first
signal for setting re-attachment, when the MME decides that it is
necessary to re-select a gateway apparatus, the user equipment
transmits a second signal for re-attachment to the MME, on receipt
of the first signal, and the MME re-selects the gateway apparatus.
There is also provided a communication system in Selected IP
Traffic Offload (SIPTO) architecture, wherein a mobility management
entity (MME) sends a first signal for setting re-attachment to a
user equipment, when the MME decides that it is necessary to
re-select a gateway apparatus; the user equipment, on receipt of
the first signal, transmits a second signal for re-attachment to
the MME; and the MME, based on a delete session response that is
received by a serving gateway apparatus connected to the MME from a
packet data network gateway apparatus, performs re-selection of a
packet data network gateway apparatus.
[0017] According to the present invention, there is provided a user
equipment in a communication system by Local IP Access
(LIPA)/Selected IP Traffic Offload (SIPTO) architecture, wherein
the user equipment receives a first signal that sets re-attachment
from a mobility management entity (MME) and transmits a second
signal for re-attachment to the MME to cause re-selection of a
gateway apparatus to be performed. There is also provided a user
equipment in a communication system by Selected IP Traffic Offload
(SIPTO) architecture, wherein the user equipment receives a first
signal that sets re-attachment from a mobility management entity
(MME) and transmits a second signal for re-attachment to the MME to
cause the MME, based on a delete session response that is received
by a serving gateway apparatus connected to the MME from a packet
data network gateway apparatus, to perform re-selection of a packet
data network gateway apparatus.
[0018] In yet another aspect of the present invention, there is
provided a communication method in Local IP Access (LIPA)/Selected
IP Traffic Offload (SIPTO) architecture, wherein the method
comprises:
[0019] the MME sending a deactivate bearer request (Deactivate
Bearer request), requesting re-selection, to a base station, when a
mobility management entity (MME) decides that it is necessary to
re-select a gateway apparatus;
[0020] the base station sending an RRC connection reconfiguration
(RRC connection reconfiguration) to a user equipment; and
[0021] the user equipment sending a notification of completion of
an RRC connection reconfiguration (RRC connection reconfiguration)
to the base station;
[0022] the base station sending a deactivate bearer response
(Deactivate Bearer response) to the MME; and
[0023] the user equipment initiating a UE requested PDN
connectivity (UE requested PDN connectivity) procedure,
[0024] as a result, re-selection of a gateway apparatus being
performed.
[0025] According to the present invention, there is provided a
communication system in Local IP Access (LIPA)/Selected IP Traffic
Offload (SIPTO) architecture, comprising:
[0026] a mobility management entity (MME);
[0027] a base station; and
[0028] a user equipment, wherein when the MME decides that it is
necessary to re-select a gateway apparatus, the MME sends a
deactivate bearer request (Deactivate Bearer request), requesting
re-selection, to the base station,
[0029] the base station sends an RRC connection reconfiguration
(RRC connection reconfiguration) to the user equipment,
[0030] the user equipment sends a notification of completion of the
RRC connection reconfiguration (RRC connection reconfiguration) to
the base station,
[0031] the base station sends a deactivate bearer response
(Deactivate Bearer response) to the MME, and
[0032] the user equipment initiates a UE requested PDN connectivity
(UE requested PDN connectivity) procedure to cause re-selection of
a gateway apparatus to be performed.
[0033] According to the present invention, there is provided a user
equipment in a communication system by Local IP Access
(LIPA)/Selected IP Traffic Offload (SIPTO) architecture, wherein,
in case of receiving an RRC connection reconfiguration from the
base station, the user equipment sends a notification of completion
of RRC connection reconfiguration to the base station to initiate a
UE requested PDN connectivity procedure to cause re-selection of a
gateway apparatus to be performed.
[0034] According to the present invention, it is possible to
re-select an optimal gateway node at a time when a user equipment
is to connect from a serving area to an external network (service
network).
[0035] Still other features and advantages of the present invention
will become readily apparent to those skilled in this art from the
following detailed description in conjunction with the accompanying
drawings wherein only exemplary embodiments of the invention are
shown and described, simply by way of illustration of the best mode
contemplated of carrying out this invention. As will be realized,
the invention is capable of other and different embodiments, and
its several details are capable of modifications in various obvious
respects, all without departing from the invention. Accordingly,
the drawing and description are to be regarded as illustrative in
nature, and not as restrictive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] FIG. 1 is a diagram showing a entire configuration of a
system according to an exemplary embodiment of the present
invention.
[0037] FIG. 2 is a diagram for explaining a Comparative
Example.
[0038] FIG. 3 is a diagram for explaining the present
invention.
[0039] FIG. 4 is a diagram illustrating a sequence of the
Comparative Example.
[0040] FIG. 5 is a diagram illustrating a sequence of an exemplary
embodiment 1 of the present invention.
[0041] FIG. 6 is a diagram illustrating a sequence of an exemplary
embodiment 2 of the present invention.
[0042] FIG. 7 is a diagram illustrating a sequence of an exemplary
embodiment 3 of the present invention.
[0043] FIG. 8 is a diagram illustrating a sequence of an exemplary
embodiment 4 of the present invention.
[0044] FIG. 9 is a diagram showing a configuration of an exemplary
embodiment 5 of the present invention.
[0045] FIG. 10 is a diagram showing a configuration of an exemplary
embodiment 6 of the present invention.
[0046] FIG. 11 is a diagram illustrating a sequence of the
exemplary embodiment 5 of the present invention.
[0047] FIG. 12 is a diagram illustrating a sequence of the
exemplary embodiment 6 of the present invention.
[0048] FIG. 13 is a diagram illustrating a sequence of an exemplary
embodiment 7 of the present invention.
[0049] FIG. 14 is a diagram illustrating a sequence of an exemplary
embodiment 8 of the present invention.
PREFERRED MODES
[0050] The following describes exemplary embodiments of the present
invention will now be described. A system according to one of modes
of the present invention re-selects a PGW (PDN gateway) in EPC in
keeping with movement of a user equipment (UE) and re-establishes a
default bearer, thereby realizing improvement of transmission delay
and efficiency of network resources in the EPC.
[0051] In current 3GPP standardization, such techniques, termed
LIPA (Local IP Access) or SIPTO (Selected IP Traffic Offload), are
under study. In these techniques, user traffic is not taken into
EPC and is made to have direct access to an external packet network
from a radio access network, in which a UE resides. In case the
present invention is adapted to cooperate with the LIPA/SIPTO
architecture, it becomes possible to realize efficient utilization
of network resource more effectively.
[0052] In a system according to an exemplary embodiment of the
present invention, a PGW is re-selected for a UE which is being
attached to the EPC.
[0053] An EPC bearer usually uses in a fixed manner, a PGW which is
initially selected when a UE is attached (registered) to the EPC
network, as an anchor, until the UE is detached (deleted from
registration). However, in case the UE moves over a long distance,
it may occur frequently that the PGW initially selected ceases to
be a most efficient gateway apparatus for the external network.
[0054] In one of modes of the present invention, a path (bearer)
between a UE and a PGW may be optimized by re-selecting and
modifying the PGW, such as when the UE is in an idle state.
[0055] In one of modes of the present invention, a default bearer
is re-established, with the re-selection of as the PGW, when the UE
is not involved in packet communication, i.e., when the UE is in
idle mode. By so doing, network resources between UE and PGW may be
optimized without detracting from the user experience.
[0056] The following describes the operation in case the UE moved
astride an SGW. FIG. 2 shows, as Comparative Example, a case where
the present invention is not applied. Referring to FIG. 2, since
the UE is attached to an SGW 61 on the left side of FIG. 2, a PGW
71, which is closer to the left side SGW 61 in a physical distance
or a network-topological distance, is initially selected, and a
connection path 1 is set. When the UE is moved a long distance, the
UE continues to use the left-side PGW 71. Hence, the UE and the PGW
are connected by an inefficient connection path 2.
[0057] In contrast, FIG. 3 shows a case where the UE moves astride
the SGW, as the present invention is applied. Referring to FIG. 3,
since the UE is attached to the SGW 61 on the left side of FIG. 3,
the PGW 71, closer to the left side SGW 61 in a physical distance
or a network-topological distance, is initially selected, and a
connection path 3 is set. The EPC then re-examines the connectivity
between the UE and the external network (service network), using
the UE's movement over the large distance as a trigger. As a result
of the re-check, the EPC gives a decision that a right-side PGW2
provides a more efficient connection (UE-PGW path) than the
left-side PGW 71. Hence, the path between the UE and the PGW is
changed over from the connection path 3 to the connection path 4,
thus assuring more efficient connection. The present invention will
now be described with reference to exemplary embodiments.
Exemplary Embodiment 1
[0058] FIG. 1 shows the arrangement of a network system according
of the present exemplary embodiment. The basic arrangement itself
of the network remains unchanged from a hitherto-used EPC network
arrangement.
[0059] Referring to FIG. 1, UE1 to UE3 are mobile phones. In FIG.
1, eNodeB (evolved Node B) are base stations of LTE (Long Term
Evolution), while NodeB 21 and RNC (Radio Network Controller) 31
are apparatuses for radio access adopted in the UMTS (Universal
Mobile Telecommunication System).
[0060] An MME (Mobility Management Entity) 41 is an apparatus for
mobility management as introduced by EPC.
[0061] An SGSN (Serving GPRS (General Packet Radio Service) Support
Node) 51 is a serving apparatus, used for UMTS, and may or may not
handle a user plane processing, depending on a connection
modes.
[0062] In case the SGSN does not handle a user plane, the user
plane is set between the SGW (Serving Gateway) and the RNC.
[0063] SGWs 61 and 62 are serving apparatuses that may handle the
user plane. PGW 71 and 72 are gateway apparatuses that connect an
external network (a service network 81 in the drawing) and RNC.
[0064] The following describes the operation of the present
exemplary embodiment. Initially, an update procedure of a tracking
area (TA Update Procedure) will be described with reference to a
Comparative Example to which the present invention is not
applied.
[0065] FIG. 4 shows a case of TA update accompanied by SGW change
(Comparative Example). It is noted that, when a UE is in idle
condition, that is, in a no-connection state, it is managed to
which tracking area (position registration area) the UE belongs,
however, it is not managed in which cell the UE resides.
[0066] MME receives a TA update request (TA Update Request) from
the UE and, if it is determined that SGW needs to be changed, a
create session request (Create Session Request) is sent to an SGW
(2) which is a change-target SGW.
[0067] The SGW (2) sends a modify bearer request (Modify Bearer
Request) to the PGW (1) to notify the PGW (1) of the fact that the
SGW as destination of connection is changed.
[0068] On completion of update of the bearer context information,
the PGW (1) sends a response to the modify bearer request (Modify
Bearer Response) to the SGW (2).
[0069] On receipt of the response to the modify bearer request
(Modify Bearer Response) from the PGW (1), the SGW (2) sends a
create session response (Create Session Response) to the MME.
[0070] On receipt of the create session response (normal response)
from the SGW (2), the MME sends a delete session request (Delete
Session Request) to the SGW (1), which is a change-source SGW.
[0071] After deletion of the bearer context, the SGW (1) sends a
delete session response (Delete Session Response) to the MME.
[0072] On receipt of the delete session response (Delete Session
Response) from the SGW (1), the MME sends a TA (Tracking Access)
accept (TA accept) to the UE.
[0073] In contrast to the Comparative Example, shown in FIG. 4, the
sequence operation shown in FIG. 5 is carried out in an exemplary
embodiment of the present invention. The following describes the
sequence of the present exemplary embodiment with reference to FIG.
5.
[0074] The MME receives a TA update request (TA Update Request)
from the UE. In case the MME decides that the SGW is to be changed,
the MME sends a create session request (Create Session Request) to
the SWG (2) which is a change-target SGW.
[0075] In case the MME decides that PGW re-arrangement is
necessary, the MME selects a PGW (2) that can be efficiently
connected to the external network (service network), and sets
address information that identifies the PGW, in the create session
request (Create Session Request).
[0076] The SGW (2), on receipt of the new PGW address, sends a
create session request (Create Session Request) to the PGW (2).
[0077] The PGW (2), responsive to the create session request
(Create Session Request) sent from the SGW (2), creates a bearer
context. The PGW (2) also assigns a new IP address for the user to
the UE. After completion of assignment of the new IP address for
the user and creation of the bearer context, the PGW (2) sends a
create session response (Create Session Response) to the SGW
(2).
[0078] The SGW (2), responsive to the create session response
(Create Session Request) from the PGW (2), sends a delete session
request (Delete Session Request) to the PGW (1).
[0079] The PGW (1) deletes the bearer context and sends a delete
session response (Delete Session Response) to the SGW (2).
[0080] The SGW (2), responsive to the delete session response
(Delete Session Response) from the PGW (1), sends a create session
response (Create Session Response) to the MME.
[0081] The MME, responsive to a normal response from the SGW (2),
sends a delete session request (Delete Session Request) to the SGW
(1), which is the change-source SGW.
[0082] After deleting bearer context, the SGW (1) sends a delete
session response (Delete Session Response) to the MME.
[0083] On receipt of the response, the MME sends a TA update accept
(TA Update Accept) to the user. The IP information, newly assigned
to the user, is set in the TA Update Accept and notified to the
UE.
[0084] In the foregoing, such a case has been explained in which
GTPv2 protocol (GPRS (General Packet Radio Service) Tunneling
Protocol v2) is used between SGW and PGW. Similar functions may be
implemented for such a case where PMIPv6 (Proxy Mobile IPv6) is
used.
[0085] In case of using PMIPv6 between the SGW and the PGW, Proxy
Binding Update is used in place of Create Session Request/Delete
Session Request. Also, Proxy Binding Acknowledgement is used in
place of Create Session Response/Delete Session Response.
[0086] The sequence to re-select a PGW is as shown in FIG. 5. To
implement the above functions, it is necessary for an MME to
re-select a PGW at an appropriate timing.
[0087] If, during when a UE is performing packet communication, a
PGW connected to a service network is changed, the information such
as IP address is changed for a communication counterpart of the UE.
As a result, the packet communication by the UE is disconnected.
Thus, in the operation shown in FIG. 5, it is necessary to
re-select a PGW, during when the UE is not performing packet
communication, that is, during ECM (EPS Connection Management)-IDLE
time).
[0088] FIG. 5 shows the operation when an SGW is changed. However,
even in case an SGW is not changed, the basic operation is the
same. The message sequence, shown in FIG. 5, is explained using
message names for a case where the communication between an SGW and
a PGW is implemented in accordance with GTP protocol. However,
similar effects may also be obtained in case the communication
between the SGW and the PGW is implemented in accordance with PMIP
(Proxy Mobile IP) protocol.
[0089] If, in FIG. 5, an SGSN is substituted for an MME, the
operation is that of PGW re-selection in case an access network is
UMTS.
[0090] In the present exemplary embodiment, described above, the
following operation and advantageous effect may be obtained.
[0091] The selection of PGW based on the position in which a UE
resides becomes possible. Since a PGW which is of a physically
short distance from the UE or network-topologically close to the UE
is selected and connected to the UE, network resources may be
optimized by efficient connection.
[0092] User data transmission delay may be reduced by efficient
path connection between the UE and the PGW.
[0093] Cooperated with the LIPA/SIPTO architecture, it becomes
possible to provide packet communication services without user data
being taken into the EPC. Hence, it becomes possible for a mobile
communication operator to reduce a load of an EPC network
apparatus.
Exemplary Embodiment 2
[0094] The following describes a second exemplary embodiment of the
present invention with reference to FIG. 6. On receipt of a TA
update request (TA Update Request), sent from a terminal (UE), MME
examines whether or not a PGW, to which the UE is connected, is
appropriate.
[0095] FIG. 6 shows a status in which a UE is connected to a PGW
(1) (an EPS bearer established between the UE and the PGW (1): EPS
bearer originally established).
[0096] In case the MME decides that re-selection of another
suitable PGW is necessary, the MME sets a cause value that urges
re-attach in a TA update request (TA Update Request) to send a TA
update reject (TA Update Reject) to the UE.
[0097] In response to the TA update reject (TA Update Reject) from
the MME, the UE sends an attach (ATTACH) signal to the MME. On
receipt of the TA update reject (TA Update Reject), the MME is able
to newly start up a logic for selecting a PGW, as a result of which
an optimal PGW is re-selected.
[0098] In the example of FIG. 6, such a case is shown in which a
PGW (2) is re-selected to perform a connection procedure to the PGW
(2). That is, a create session request (Create Session Request)
from the MME is sent to the SGM (2) and the create session request
(Create Session Request) is sent from the SGW (2) to the PGW (2).
On receipt of a create session response (Create Session Response)
from the PGW (2), the SGW (2) sends the create session response to
the MME. MME sends a delete session request (Delete Session
Request) to the SGW (1). The SGW (1) returns a delete session
response (Delete Session Response) to the MME. On receipt of the
delete session response, the MME returns TA Update Accept which
indicates the completion of TA update, to the terminal (UE).
[0099] In the present exemplary embodiment, the following operation
and advantageous effect may be obtained.
[0100] In the present exemplary embodiment 2, no impact is imposed
on a UE in the first exemplary embodiment, while minimum changes
may suffice insofar as the EPC is concerned.
Exemplary Embodiment 3
[0101] The following describes a third exemplary embodiment of the
present invention with reference to FIG. 7. In the present
exemplary embodiment, the usual TA update procedure is slightly
changed.
[0102] The sequence shown in FIG. 7 is a normal TA update
procedure. As a point of change in the present exemplary
embodiment, completion of the TA update procedure is notified from
an MME to a UE.
[0103] Referring to FIG. 7, on receipt of a TA update request (TA
Update Request) from the UE, the MME sends a create session request
(Create Session Request) to the SGW (2). A modify bearer request
(Modify Bearer Request) is sent from the SGW (2) to the PGW (1). On
receipt of a create session response (Create Session Response) from
the SGW (2), the MME sends a delete session request (Delete Session
Request) to the SGW (1). On receipt of the delete session response
(Delete Session Response) from the SGW (1), the MME sends a TA
update accept (TA Update Accept (PDN)).
[0104] In the present exemplary embodiment, new information, that
is, PDN of the TA Update Accept (PDN) in FIG. 7, is added to a TA
Update Accept signal to urge re-connection of the packet data
network (PDN) which is currently in a connected state.
[0105] On receipt of the TA update accept (TA Update Accept)
signal, added by the new information (PDN), the UE recognizes the
PDN (packet data network) for re-connection, based on the
information specified. It is noted that a plurality of PDNs may
sometimes be so added. For the PDN, the UE starts up a UE requested
PDN Disconnection processing (processing of disconnection of the
PDN as requested by the UE) or a UE requested PDN connectivity
processing (processing of connection of the PDN as requested by the
UE) to re-connect the packet data network (PDN).
[0106] In this re-connection of the packet data network (PDN), it
is possible for the MME to newly start up the PGW selection logic.
As a result, it is necessary to re-select an optimum PGW.
[0107] FIG. 7 shows the operation for the case where the SGW is
changed. However, even when the SGW is not changed, the basic
operation remains the same.
[0108] The present exemplary embodiment has the following operation
and meritorious effect:
[0109] According to the present exemplary embodiment, PGW
re-connection may be made without starting up ATTACH processing
(re-attach).
[0110] Starting up ATACH processing means that, if there are a
plurality of PDN connections, processing for PGW re-selection is
started up for the entire PDN connections, and hence the processing
of a relatively large scale is invoked.
[0111] With the present exemplary embodiment, in contrast, only the
re-selection of the PGW needed may be made by EPC startup.
Exemplary Embodiment 4
[0112] The following described a fourth exemplary embodiment of the
present invention with reference to FIG. 8. In the fourth exemplary
embodiment of the present invention, PGW re-selection, which may be
started up by the EPC (MME) at an optional timing, is made in a
manner not dependent upon the TA update procedure carried out by
the UE. If, when the MME is in a connected state, PGW re-selection
is decided to be necessary, a Page signal is sent to the UE and the
connection with the UE is tried.
[0113] It is noted that the cause information (reason information)
is added as an option to the Page signal. See Page (cause) of FIG.
8. The UE is allowed to neglect this Page signal (Page signal with
the cause information). This is a measure taken in order to avoid
battery consumption in the UE caused by iterative execution of this
processing.
[0114] Inherently, the Page signal is a signal used for
notification of an incoming call. In contrast, the Page signal,
sent in case PGW re-selection is needed, is for enhancing the
efficiency of the connection path in the EPC, such that it may not
be said to be an indispensable operation. On receipt of this Page
signal, the UE sends a service request (Service request) signal to
the MME for communication therewith. The MME sends a deactivate
bearer request (Deactivate Bearer request) from the MME to the
eNodeB. The eNodeB sends an RRC connection reconfiguration. On
receipt of a notification of completion of the RRC connection
reconfiguration from the UE, the eNodeB sends a deactivate bearer
response (Deactivate Bearer Response) to the MME.
[0115] The MME then disconnects the connection of the packet data
network (PDN), for which PGW re-selection is necessary, to induce
the procedure of UE requested packet data network connection from
the UE (UE requested PDN connectivity).
[0116] By carrying out this procedure, it becomes possible for the
MME to newly start up the PGW selection logic. Thus, as a result,
re-selection of suitable PGW becomes necessary. For this procedure,
the EPC (MME) is able to start up PGW re-connection at an optional
timing. In this case, O&M (Operation and Maintenance), LIPA or
SIPTO connection/disconnection may be used as a trigger.
[0117] In the present exemplary embodiment, such operation and
meritorious effect may be obtained that the MME may re-select PGW
at an optional timing.
Exemplary Embodiment 5
[0118] The following describes a utilization example of the present
invention to a LIPA or SIPTO architecture. FIGS. 9 and 10 show the
arrangement of the present exemplary embodiment.
[0119] Referring to FIG. 9, UE1 to UE3 are mobile phone
apparatuses. eNodeB 11 and 12 are LTE base stations. NodeB 21 and
RNC 31 are apparatuses for radio access (Radio Access) adopted by
the UMTS system. An MME 41 is an apparatus introduced by EPC to
manage the mobility. An SGSN 51 is a serving apparatus used for the
UMTS, and may or may not handle a user plane depending upon
connection configurations. In case the SGSN does not handle a user
plane, the user plane is set between the SGW and the RNC.
[0120] SGWs 61 and 62 are apparatuses inside the service range that
handle the user plane. The PGW 71 and 72 are gateway apparatuses
that interconnect the external network (service network 81 in FIG.
9) and the EPC. LPGW (Local PGW 91 and 92) are gateway apparatuses
that share certain portions in common with the eNodeB or that are
located extremely close to the eNodeB and to allow connection to
the service network 81.
[0121] In FIG. 10, UE1 and UE2 are mobile phone apparatuses. NodeB
21 and 22 and RNC 31 and 32 are apparatuses for radio access
adopted in the UMTS system. SGSNs 61 and 62 are serving apparatuses
and may or may not handle the user plane depending upon connection
configurations. In case the SGSN does not handle a user plane, the
user plane is set between the GGSN and RNC. It is noted that the
configuration in which the user plane is set between the GGSN and
RNC is called the `direct tunnel connection`.
[0122] GGSNs 71 and 72 are gateway apparatuses that interconnect
the external network (service network 81 in FIG. 10) and GPRS
(General Packet Radio Service) network.
[0123] LGGSNs (Local GGSNs (Gateway GPRS Support Nodes)) 101 and
102 are gateway apparatuses that share certain portions in common
with or are located extremely close to the RNCs (Radio Network
Controllers) and that allow for connection to the service network
81.
[0124] The following describes the operation of the fifth exemplary
embodiment shown in FIG. 9, with reference to the sequence diagram
shown in FIG. 11.
[0125] The MME receives a TA update request (TA Update Request)
from the UE. In case the architecture is that of LIPA or SIPTO, the
TA update request (TA Update Request) signal from the eNodeB to the
MME is encapsulated in the S1-AP message for transmission.
[0126] At this time, the eNodeB notifies the MME on the S1-AP
message of the fact that PDN connection may be set by the
LIPA/SIPTO architecture.
[0127] In case the MME decides that the SGW needs to be changed, it
sends a create session request (Create Session Request) to the SGW
(2) which is a change-target SGW.
[0128] In case the MME decides that re-arrangement to LPGW is
necessary, the MME selects an LPGW that may efficiently be
connected to the external network (service network 81), and sets
address information that designates the PGW, in the create session
request (Create Session Request). It is noted that the above
mentioned notification on the S1-AP message that PDN connection may
be set by the LIPA/SIPTO architecture is by way of illustration
only such that it is also possible for the MME to decide on the
necessity for re-selection based on some other information.
[0129] On receipt of a new PGW address, the SGW (2) sends a create
session request (Create Session Request) to the LPGW. On receipt of
the create session request (Create Session Request), the LPGW
creates a bearer context (Bearer Context).
[0130] The LPGW assigns a new IP address for the user to the
UE.
[0131] On completion of assignment of the new IP address for the
user and creation of the bearer context (Bearer Context), the LPGW
sends a create session response (Create Session Response) to the
SGW (2).
[0132] On receipt of the create session response (Create Session
Response), the SGW (2) sends a delete session request (Delete
Session Request) to the PGW (1).
[0133] The PGW (1) deletes the bearer context (Bearer Context) and
sends a delete session response (Delete Session Response) to the
SGW (2).
[0134] On receipt of the delete session response (Delete Session
Response), the SGW (2) sends a create session response (Create
[0135] Session Response) to the MME.
[0136] On receipt of the normal response from the LPGW, the MME
sends a delete session request (Delete Session Request) to the SGW
(1), a change-source SGW.
[0137] After deleting the bearer context (Bearer Context), the SGW
(1) sends a delete session response (Delete Session Response) to
the MME.
[0138] On receipt of the delete session response (Delete Session
Response), the MME sends TA accept (TA Accept) to the UE. In this
TA accept (TA Accept), IP address information, newly assigned to
the user, is set and notified of the UE.
[0139] The foregoing description is for the case of using GTPv2
protocol between the SGW and the PGW. Similar functions may,
however, be implemented using PMIPv6.
[0140] In this case, Proxy Binding Update is used in place of the
create session request (Create Session Request)/delete session
request (Delete Session Request). Also, proxy binding
acknowledgement (Proxy Binding Acknowledgement) is used in place of
the create session response (Create Session Response)/delete
session response (Delete Session Response).
[0141] The sequence for LPGW re-selection is shown in FIG. 11.
However, if the above function is to be implemented, it is
necessary for the MME to re-select the PGW at an appropriate
timing.
[0142] If, when the UE is engaged in packet communication, it is
tried to change the PGW connected to the service network, the
information such as the IP address is changed for the UE's
counterpart of communication. As a result, the packet communication
by the UE is disconnected. Thus, in the sequence operation shown in
FIG. 11, it is necessary to re-select the PGW when the UE is not
engaged in packet communication. That is, PGW re-selection is to be
made during the ECM-IDLE time.
[0143] FIG. 11 shows the operation when the SGW is changed.
However, even in case the SGW is not changed, the basic operation
is the same. The message sequence, shown in FIG. 11, is explained
in terms of message names for a case where the communication
between the SGW and the PGW is implemented using GTP protocol.
However, similar effects may also be obtained in case the
communication between the SGW and the PGW is implemented using PMIP
protocol.
[0144] If, in FIG. 11, the MME is substituted by the SGSN, and the
eNodeB is substituted by RNC, the operation is that of PGW
re-selection in case the access network is the UMTS.
[0145] In the present exemplary embodiment, as described above,
packet communication services may be extended by LPGW re-selection
as no user traffic is taken into the EPC. Hence, a mobile
communication operator is able to reduce a load of an EPC network
apparatus.
Exemplary Embodiment 6
[0146] Following describes a sixth exemplary embodiment of the
present invention will now be described. The configuration of the
present exemplary embodiment is that as shown FIG. 9. The following
describes the operation of the present exemplary embodiment will
now be set out with reference to FIG. 12.
[0147] The MME receives a TA update request (TA Update Request)
from the UE. In the case of the LIPA/SIPTO architecture, a TA
update request (TA Update Request) signal is encapsulated in the
S1-AP message for communication from the eNodeB to the ME. The
eNodeB sends to the MME a notification on the S1-AP message to the
effect that PDN connection may be set based on the LIPA/SIPTO
architecture.
[0148] The MME examines whether or not the PGW, the UE in question
is connected to, is appropriate. It is noted that the above
mentioned notification on the S1-AP message that setting of PDN
connection by the LIPA/SIPTO architecture is possible is by way of
illustration only such that it is also possible for the MME to
decide on the necessity for re-selection of a new PGW based on some
other information.
[0149] FIG. 12 shows a state in which the UE is connected to PGW
(1) (EPS bearer originally established from the UE to the PGW (1)).
In case the MME decides that LPGW re-selection is necessary, it
sets a cause value that urges re-attach (ATTACH) in the TA update
request (TA Update Request) and returns a TA update reject (TA
Update Reject) to the UE.
[0150] The UE is induced by the TA update reject (TA Update Reject)
to send the ATTACH signal to the MME. This ATTACH signal is also
encapsulated in the S1-AP message for transmission. The eNodeB
sends to the MME a notification on the S1-AP message to the effect
that PDN connection may be set based on the LIPA/SIPTO
architecture.
[0151] It is now possible for the MME to newly start up the PGW
selection logic. As a result, it becomes necessary to re-select
LPGW.
[0152] FIG. 12 shows an example connection processing to LPGW
re-selected. A create session request (Create Session Request) from
the MME to the SGW (2) and LPGW, a create session response (Create
Session Response) from the LPGW to the SGW (2) and MME, a delete
session request (Delete Session Request) from the MME to the SGW
(1), a delete session response (Delete Session Response) from the
SGW (1) to the MME and a TA update accept from the MME to the UE,
are sent.
[0153] In the present exemplary embodiment, as described above,
packet communication services may be extended by LPGW re-selection
as no user traffic is taken into EPC. Hence, a mobile communication
operator is able to reduce a load of an EPC network apparatus.
Exemplary Embodiment 7
[0154] The following describes a seventh exemplary embodiment of
the present invention will now be described. The configuration of
the present exemplary embodiment is that as shown FIG. 9. The
operation of the present exemplary embodiment will now be described
with reference to FIG. 13. In the present exemplary embodiment, the
regular TA update procedure is changed.
[0155] The MME receives a TA update request (TA Update Request)
from the UE. It is noted that, in the case of the LIPA/SIPTO
architecture, the TA update request (TA Update Request) signal from
the eNodeB to the MME is encapsulated in the S1-AP message for
transmission.
[0156] At this time, a notification is sent on the S1-AP message to
the MME to the effect that PDN connection may be set based on the
LIPA/SIPTO architecture. It is noted however that the notification
sent on the S1-AP message to the effect that PDN connection may be
set based on the LIPA/SIPTO architecture is by way of illustration
only such that it is also possible for the MME to decide on the
necessity for re-selection of a new PGW based on some other
information.
[0157] The TA update accept (TA Update Accept) signal that notifies
the completion of the TA update procedure from the MME to the UE is
added by new information (PDN in FIG. 13) to urge re-connection of
the packet data network (PDN) which is currently in a connected
state. On receipt of the TA update accept (TA Update Accept) signal
added by the new information (PDN), the UE recognizes the PDN
(packet data network) for re-connection, based on the information
specified. It is noted that a plurality of PDNs may sometimes be so
added. For the PDN in question, the UE starts up the conventional
UE requested PDN connection processing or the UE requested PDN
connectivity processing to re-connect the packet data network
(PDN).
[0158] In this re-connection of the packet data network (PDN), it
is possible for the MME to newly start up the PGW selection logic,
as a result of which it becomes necessary to re-select an optimum
PGW.
[0159] The operation for the case where the SGW is to be changed
has been explained with reference to FIG. 13. However, even when
the SGW is not changed, the basic operation remains the same.
[0160] In the present exemplary embodiment, as described above,
packet communication services may be extended by LPGW re-selection
as no user traffic is taken into EPC. Hence, mobile communication
operator is able to reduce a load of an EPC network apparatus.
Exemplary Embodiment 8
[0161] The following describes an eighth exemplary embodiment of
the present invention. The configuration of the present exemplary
embodiment is that as shown FIG. 10. The operation of the present
exemplary embodiment will now be described with reference to FIG.
14.
[0162] The SGSN (Serving GPRS Support Node) receives an RA (Routing
Area) update request (RA Update Request) from the UE. In the case
of the LIPA/SIPTO architecture, the RA update request signal from
the NodeB to the SGSN is encapsulated in a RANUP (Radio Access
Network Access Part) message for transmission. The RRC sends to the
SGSN a notification on the RANAP message to the effect that PDN
connection may be set based on the LIPA/SIPTO architecture.
[0163] The SGSN examines whether or not the GGSN (Gateway GPRS
Support Node), the UE in question is connected to, is appropriate.
It is noted that the above mentioned notification on the RANAP
message that PDN connection setting by the LIPA/SIPTO architecture
is possible is only by way of illustration. That is, it is also
possible for the MME to decide on the necessity for re-selection of
a new PGW based on some other information.
[0164] FIG. 14 shows a state in which the UE is connected to GGSN
(GTP tunnel connection is established between UE and GGSN: see `GTP
Tunneling originally established` of FIG. 14).
[0165] In case the SGSN decides that LGGSN re-selection is
necessary, the SGSN sets a reason value (cause value) that urges
re-attach (ATTACH) in the RA update request (RA Update Request) to
send back an RA update reject (RA Update Reject) signal to the
UE.
[0166] The UE is caused by the RA update reject (RA Update Reject)
signal to send the ATTACH signal to the SGSN to try to re-attach
(ATTACH) to the GPRS network. The SGSN sends an RA update request
(RA Update Request) to an HLR (Home Location Register). An insert
subscriber data (Insert Subscriber data) is sent from the HLR to
the GGSN. The GGSN sends back an insert subscriber data acknowledge
(Insert Subscriber data ack) response to the HLR. On receipt of the
ack response (ack), the HLR sends back an RA update response (RA
Update Response) to the SGSN. The SGSN sends back an ATTACH accept
(ATTACH Accept) to the UE.
[0167] The UE then sends a request for activating PDP context
(Activate PDP context request), requesting PDP (Packet Data
Protocol) connection, to the SGSN.
[0168] On receipt of the request for activating PDP context
(Activate PDP context request), the SGSN decides whether or not the
connection to LGGSN is appropriate. When the SGSN decides that the
connection to LGGSN is appropriate, the SGSN performs creation of a
GTP (GPRS Tunneling Protocol) tunnel to the LGGSN (Create PDP
context request). The Create PDP context request is sent back from
the LGGSN to the SGSN, and a PDP context activate response
(Activate PDP context response) is sent back from SGSN to the UE to
enable connection between UE and LGGSN.
[0169] In the present exemplary embodiment, as described above,
packet communication services may be extended by LPGW re-selection
as no user traffic is taken into the EPC. Hence, a mobile
communication operator is able to reduce a load of a GPRS network
apparatus.
[0170] The particular exemplary embodiments or examples may be
changed or adjusted within the gamut of the entire disclosure of
the present invention, inclusive of claims, based on the
fundamental technical concept of the invention. Further, variegated
combinations or selection of elements disclosed herein may be made
within the framework of the claims. That is, the present invention
may encompass various modifications or corrections that may occur
to those skilled in the art in accordance with and within the gamut
of the entire disclosure of the present invention, inclusive of
claim and the technical concept of the present invention.
* * * * *