U.S. patent application number 14/509988 was filed with the patent office on 2015-01-22 for control station, mobile station, mobile communication system and mobile communication method.
This patent application is currently assigned to SHARP KABUSHIKI KAISHA. The applicant listed for this patent is SHARP KABUSHIKI KAISHA. Invention is credited to Masafumi ARAMOTO, Hirokazu NAOE.
Application Number | 20150023322 14/509988 |
Document ID | / |
Family ID | 42152874 |
Filed Date | 2015-01-22 |
United States Patent
Application |
20150023322 |
Kind Code |
A1 |
ARAMOTO; Masafumi ; et
al. |
January 22, 2015 |
CONTROL STATION, MOBILE STATION, MOBILE COMMUNICATION SYSTEM AND
MOBILE COMMUNICATION METHOD
Abstract
A mobile station that establishes a first transfer path by way
of a first access network between the mobile station and a control
station. The mobile station establishes a default EPS (Evolved
Packet System) bearer by way of a second access network between the
mobile station and the control station by transmitting an attach
request for requesting a handover of a partial flow among the
plurality of flows when performing transmission/reception of a
plurality of flows with the control station by using the first
transfer path.
Inventors: |
ARAMOTO; Masafumi; (Osaka,
JP) ; NAOE; Hirokazu; (Osaka, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SHARP KABUSHIKI KAISHA |
Osaka |
|
JP |
|
|
Assignee: |
SHARP KABUSHIKI KAISHA
Osaka
JP
|
Family ID: |
42152874 |
Appl. No.: |
14/509988 |
Filed: |
October 8, 2014 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13127727 |
May 5, 2011 |
8885612 |
|
|
PCT/JP2009/068750 |
Nov 2, 2009 |
|
|
|
14509988 |
|
|
|
|
Current U.S.
Class: |
370/331 |
Current CPC
Class: |
H04W 36/26 20130101;
H04W 36/14 20130101; H04W 28/10 20130101 |
Class at
Publication: |
370/331 |
International
Class: |
H04W 36/14 20060101
H04W036/14 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 6, 2008 |
JP |
2008-285689 |
Claims
1. A mobile station comprising: a control circuit configured to
establish a first transfer path by way of a first access network
between the mobile station and a control station; wherein, when
performing transmission/reception of a plurality of flows with the
control station by using the first transfer path, the control
circuit is configured to establish a default EPS (Evolved Packet
System) bearer by way of a second access network between the mobile
station and the control station by transmitting an attach request
for requesting a handover of a partial flow among the plurality of
flows.
2. A mobile station comprising: a first transceiver configured to
connect to a first access network; a second transceiver configured
to connect to a second access network; a storage configured to
store 1) a first flow information which identifies a first
application, 2) a second flow information which identifies a second
application, 3) a first transfer path information which corresponds
to the first flow information, and 4) a second transfer path
information which corresponds to the second flow information; a
first transfer path establishment processor configured to
establish, through the first transceiver, a first transfer path by
way of the first access network by using the first flow
information; a second transfer path establishment processor
configured to establish, through the second transceiver, a second
transfer path by way of the second access network by using the
second flow information; a packet transceiver configured to
transmit and receive a packet; and a controller configured to
control the first and second transceivers, the storage, the first
and second transfer path establishment processors, and the packet
transceiver.
Description
[0001] This application is a Continuation of co-pending application
Ser. No. 13/127,727 filed on May 5, 2011, and for which priority is
claimed under 35 U.S.C. .sctn.120, application Ser. No. 13/127, 727
is the national phase of PCT International Application No.
PCT/JP2009/068750 filed on Nov. 2, 2009 under 35 U.S.C. .sctn.371,
which claims the benefit of priority of JP2008-285689 filed Nov. 6,
2008. The entire contents of each of the above-identified
applications are hereby incorporated by reference.
TECHNICAL FIELD
[0002] The present invention relates to a control station or the
like which is set with a mobile station connectable to a first
access network capable of establishing a bearer transfer path that
guarantees a predetermined QoS and a second access network
different from the first access network; and a path for performing
communication of a plurality of flows by way of the second access
network. The control station includes: an attach request receiving
means that receives an attach request in order for the mobile
station to perform a handover from the second access network to the
first access network; and a bearer establishing means that
establishes a bearer on the first access network when receiving the
attach request.
BACKGROUND ART
[0003] Conventionally, in mobile communication systems, there have
been various known techniques to control the handoverof a mobile
station between different networks (e.g., between a 3GPP standard
network and a WLAN, or the like).
[0004] Mobile control (handover) in the conventional mobile
communication networks is defined in non-patent document 1 and
non-patent document 2, for example. Now, a conventional mobile
communication system will be described with reference to FIG. 13. A
mobile communication system 9 in FIG. 13 is an embodiment of a
mobile communication system described in non-patent document 1.
[0005] In mobile communication system 9 in FIG. 13, a plurality of
access networks (access network A, access network B) are connected
to a core network. A UE (User Equipment; mobile station) 910 is
also connected to the core network via an access network. UE 910 is
connectable to the core network by way of either access network A
or access network B.
[0006] Here, access network A is a communication path for which QoS
can be set, for example a network defined by the 3GPP standard.
Provided for access network A is an eNB (base station) 950 to which
UE 910 is connected. UE 910 is connected to the core network via
eNB 950 and a gateway SGW (Serving GW) 940.
[0007] Further, a PGW (Packet Data Gateway: control station) 920
forwarding communication data to UE 910 is installed in the core
network. PGW 920 is connected to access network A via SGW 940.
[0008] Further, provided for the core network is a MME (Mobility
Management Entity: management station) 930 which receives a request
for transfer path establishment from UE 910 and takes control of
the procedure of establishing an EPS bearer as a transfer path
between UE 910 and PGW 920 via eNB 950 and SGW 940. The EPS bearer
is a transfer path between UE 910 and PGW 920 by way of access
network A.
[0009] On the other hand, access network B is provided with an AR
(Access Router) 960 to which UE 910 connects, so that UE 910 is
connected with PGW 920 in the core network via AR 960 by
establishing a transfer path based on DSMIPv6 (Dual-Stack MIPv6)
(e.g., see non patent document 3).
[0010] UE 910 is connected to PGW 920 by a transfer path, either
the DSMIPv6 transfer path or the EPS bearer. A similar transfer
path is established at a UE at the other communication end, so that
communication between UEs are performed using respective
communication paths via PGW 920.
[0011] Further, there is a defined handover procedure relating to a
case where communication that UE 910 is transmitting/receiving by
way of the DSMIPv6 transfer path via access network B is changed
over to the bearer transfer path via access network A to continue
communication.
PRIOR ART DOCUMENTS
Non-Patent Document
[0012] Non-Patent Document 1: TS23.402 Architecture enhancements
for non-3GPP accesses [0013] Non-Patent Document 2: TS23.401
General Packet Radio Service (GPRS) enhancements for Evolved
Universal Terrestrial Radio Access Network (E-UT RAN) access [0014]
Non-Patent Document 3: Mobile IPv6 Support for Dual Stack Hosts and
Routers, draft-ietf-next-memo-v4traversal-05.txt
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0015] The transmission capacity of the communication path in the
conventional mobile communication system (packet communication
system) was low in speed while there were no applications that
essentially need broadband communication. Therefore, it was not
necessary to perform complicated control such as to providing for
each application an individual communication path allotted with a
bandwidth required for that application.
[0016] However, in recent years, applications have become
diversified with the explosive spread of the internet. Various
types have become general, such as WEB access, FTP and the like
that do not need to secure bandwidth which is equal or greater than
a predetermined value, voice communication and the like that do not
need a large bandwidth but need to have the least minimum
bandwidth, and those, such as video distribution and others, that
have difficulty in operation if a large bandwidth is not
assured.
[0017] If a transfer path can be secured for an application in
conformity with the characteristic of that application, it is
possible to prevent a transfer path having a too large bandwidth
from being allotted to an application that does not need to have
that large bandwidth, and it is also possible to allot a large
enough bandwidth to an application that does need to have a large
bandwidth, thus making it possible to make efficient use of the
band.
[0018] Also in the above-described conventional technology, schemes
of performing communication by establishing a bearer as a
communication path that satisfies the QoS levels needed by
applications, have become offered, so that technologies that
satisfy both the efficient band usage and maintenance of
communication quality have come to be established.
[0019] However, there still exists an insufficient part in
performing a handover function while keeping quality, in the
network in which a UE connects to a core network via an access
network having a QoS guarantee function and a plurality of access
networks having a QoS guarantee function.
[0020] In the above-described conventional technology, when UE 910
that is performing communication by way of DSMIPv 6 transfer path
via access network B performs a handover to access network A, it
was necessary to establish a bearer as a communication path via
access network A first and change all of communications that UE 910
is making, from the DSMIPv6 communication path to the bearer
communication path at a time.
[0021] Here, it is possible to presume a situation in which UE 910
is performing a plurality of flows of communication through the
DSMIPv6 communication path. A flow is a communication
classification that can be identified based on the application or
the party at the other end. For example, an application such as a
voice communication or WEB access can be identified as a different
flow.
[0022] In conventional handovers, the communication paths of UE 910
and PGW 920 were not controlled as to flows, and it was necessary
to hand over all the flows of a UE by changing the communication
paths all at once at the time of a handover. Specifically, when a
handover is performed from a state in which a voice communication
flow `a` and a WEB access flow `b` are being practiced through the
DSMIPv6 transfer path, a bearer as a communication path via access
network A is established first, then the communication paths for
flow `a` and flow `b` are changed over in UE 910 and PGW 920 from
the DSMIPv6 transfer path to the bearer transfer path to achieve a
handover. That is, the bearer communication path and the DSMIPv6
transfer path could not be held simultaneously.
[0023] Access network A and access network B can be constructed of
different access networks, such as LTE (Long Term Evolution), radio
LAN and the like, and these networks are different in transmission
rate, presence or absence of QoS and other performance. On the
other hand, applications are different in demanded transmission
rate, necessity of QoS and other characteristics, depending on the
property of each application. Accordingly, the suited access
network is different depending on the flow, but in the prior art,
there was no means that controls the transfer paths for flows, so
that it was impossible to hand over a specific flow alone.
[0024] Further, in the prior art, defined as the bearers of the
transmission paths to be established via access network A are a
default bearer (EPS bearer 1) that does not guarantee QoS and is
not for a specific flow, and a specific EPS bearer (EPS bearer 2)
that guarantees QoS for specific flows.
[0025] However, since, in the prior art, it is impossible to
perform a handover by a unit of flow, no consideration as to QoS is
given. When a handover from the DSMIPv6 transfer path is performed,
it is necessary to establish the default bearer and then perform a
handover to the default bearer. It is possible to establish a
specific EPS bearer after continuation of communication through the
default bearer so as to enable communication through the specific
EPS bearer that satisfies the necessary QoS for the flow. However,
since it is necessary to temporarily perform communication using
the default bearer that does not satisfy the QoS level, there
occurs the problem that the quality of the flow is markedly
degraded at that time.
[0026] In the above way, in the prior art, it was impossible to
perform a handover by a unit of flow to an access network capable
of performing bearer communication, hence there has been the
problem that it is impossible to implement a handover of a flow to
the bearer with its QoS maintained even though a bearer that
supports the QoS can be established.
[0027] In view of the above-described problem, it is therefore an
object of the present invention to provide a mobile communication
system or the like in which when a mobile station performs a
handover, a specific flow among a plurality of flows is selected
and directly handed over to a bearer communication path so as to be
able to achieve a handover while keeping communication quality.
Means for Solving the Problems
[0028] In view of the above problems, a control station of the
present invention is a control station which is set with: a mobile
station connectable to a first access network capable of
establishing a bearer transfer path that guarantees a predetermined
QoS and a second access network different from the first access
network; and a path for performing communication of a plurality of
flows by way of the second access network, the control station
comprising: a bearer establishment means for establishing a bearer
on the first access network when the control station receives a
handover request for a handover from the second access network to
the first access network, from the mobile station; a specific
bearer establishment means that receives a specific bearer
establishment request including information on a flow for which a
QoS is guaranteed, from the mobile station, and establishes a
specific bearer that guarantees the QoS of the flow, based on the
specific bearer establishment request; and a path setting means
that sets up a path for performing communication of the flow
between the mobile station and the control station, on the specific
bearer.
[0029] The control station of the present invention is
characterized in that for other than the flow included in the
specific bearer establishment request, communication is continued
through the path set on the second access network.
[0030] The control station of the present invention is
characterized in that the specific bearer establishment means
establishes the specific bearer when a position register request
that the mobile station transmits after a handover includes
information on a flow for which QoS is guaranteed.
[0031] The control station of the present invention is
characterized in that a management station that receives an attach
request as a handover request from the mobile station and transmits
a bearer establishment request to the control station in accordance
with the attach request, is connected to the first network, and,
the bearer establishment means, when receiving the bearer
establishment request from the management station, establishes a
bearer on the first access network.
[0032] The control station of the present invention is
characterized in that a management station that receives the
specific bearer establishment request from the mobile station and
transmits the specific bearer establishment request to the control
station, is connected to the first network, and, the specific
bearer establishment means, when receiving the specific bearer
establishment request from the management station, establishes the
specific bearer that guarantees the QoS of the flow.
[0033] A control station of the present invention is a control
station which is set with a mobile station connectable to a first
access network capable of establishing a bearer transfer path that
guarantees a predetermined QoS and a second access network
different from the first access network, and a path for performing
communication of a plurality of flows by way of the second access
network, the control station comprising: a handover request
receiving means that receives a handover request for the mobile
station to perform a handover from the second access network to the
first access network, the handover request including information on
a flow for which QoS is guaranteed; a specific bearer establishment
means that establishes a specific bearer that guarantees the QoS of
the flow, based on the handover request; and, a path setting means
that sets up a path for performing communication of the flow
between the mobile station and the control station, on the specific
bearer.
[0034] Further, a mobile station of the present invention is a
mobile station which is connectable to a first access network
capable of establishing a bearer transfer path that guarantees a
predetermined QoS and a second access network different from the
first access network, and is set with a path for performing
communication of a plurality of flows by way of the second access
network and a control station, the mobile station comprising: a
handover request transmitting means that transmits a handover
request to the control station when the mobile station is handed
over from the second access network to the first access network;
and, a specific bearer request means for requesting the control
station to establish a specific bearer that guarantees the
necessary QoS for a flow.
[0035] The mobile station of the present invention is characterized
in that an attach request transmitted by the handover request
transmitting means is transmitted including information on a flow
for which QoS is guaranteed.
[0036] A mobile communication system of the present invention is a
mobile communication system comprising: a mobile station
connectable to a first access network capable of establishing a
bearer transfer path that guarantees a predetermined QoS and a
second access network different from the first access network; and
a control station set with a path for performing communication of a
plurality of flows by way of the second access network, the control
station comprising: a bearer establishment means for establishing a
bearer on the first access network when the control station
receives a handover request for performing a handover from the
second access network to the first access network, from the mobile
station, the mobile station comprising: a handover request
transmitting means that transmits the handover request to the
control station when the mobile station performs the handover from
the second access network to the first access network; and, a
specific bearer request means for requesting the control station to
establish a specific bearer that guarantees the necessary QoS for a
flow, the control station further comprising: a specific bearer
establishment request receiving means for receiving a specific
bearer establishment request, including information on a flow for
which QoS is guaranteed; a specific bearer establishment means for
establishing a specific bearer that guarantees the QoS of the flow,
based on the specific bearer establishment request; and a path
setup means for setting up a path for performing communication of
the flow between the mobile station and the control station, on the
specific bearer.
[0037] A mobile communication method of the present invention is a
mobile communication method including: a mobile station connectable
to a first access network capable of establishing a bearer transfer
path that guarantees a predetermined QoS and a second access
network different from the first access network; and a control
station set up with a path for performing communication of a
plurality of flows by way of the second access network, the method
comprising: the step in which the mobile station transmits a
handover request to the control station when the mobile station
performs a handover from the second access network to the first
access network; the step in which the control station establishes a
bearer on the first access network based on the handover request;
the step in which the mobile station requests the control station
to establish a specific bearer that guarantees the necessary QoS
for a flow; the step in which the control station receives the
request for the specific bearer and establishes the specific bearer
that guarantees the QoS of the flow; and, the step of setting up a
path for performing communication of the flow between the mobile
station and the control station, on the specific bearer.
Advantages of the Invention
[0038] According to the present invention, the control station is
set with a mobile station connectable to a first access network
capable of establishing a bearer transfer path that guarantees a
predetermined QoS and a second access network different from the
first access network and a path for performing communication of a
plurality of flows by way of the second access network. The control
station establishes a bearer on the first access network when
receiving a handover request for a handover from the second access
network to the f first access network, from the mobile station; and
receives a specific bearer establishment request including
information on a flow for which a QoS is guaranteed, from the
mobile station, establishes a specific bearer that guarantees the
QoS of the flow, based on the specific bearer establishment
request; and sets up a path for performing communication of the
flow between the mobile station and the control station, on the
specific bearer.
[0039] Accordingly, at the time of a handover, a flow for which QoS
is guaranteed can be put in communication, not through the bearer
established in the first access network, but through a path that is
set up on the specific bearer.
[0040] According to the present invention, for other than the flows
included in the specific bearer establishment request,
communication can be continued through the path set on the second
access network. Accordingly, it is possible to perform
communication by setting paths on both the first access network and
the second access network.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] FIG. 1 is a diagram for illustrating the overall scheme of a
mobile communication system in the present embodiment.
[0042] FIG. 2 is a diagram for illustrating the configuration of a
UE (mobile station) in the present embodiment.
[0043] FIG. 3 is a diagram for illustrating the configuration of a
PGW in the present embodiment.
[0044] FIG. 4 is a diagram for illustrating one data configuration
example of flow management tables in the present embodiment.
[0045] FIG. 5 is a diagram for illustrating the procedure of
communication path establishment in the present embodiment.
[0046] FIG. 6 is a diagram for illustrating the processing flow in
the first embodiment.
[0047] FIG. 7 is a diagram for illustrating one data configuration
example of flow management tables in the first embodiment.
[0048] FIG. 8 is a diagram for illustrating the processing flow in
the first embodiment.
[0049] FIG. 9 is a flow chart for illustrating the operation of a
PGW in the first embodiment.
[0050] FIG. 10 is a diagram for illustrating the processing flow in
the second embodiment.
[0051] FIG. 11 is a diagram for illustrating the processing flow in
the third embodiment.
[0052] FIG. 12 is a diagram for illustrating the processing flow in
the fourth embodiment.
[0053] FIG. 13 is a diagram for illustrating the overall scheme of
a conventional mobile communication system.
MODES FOR CARRYING OUT THE INVENTION
[0054] Referring next to the drawings, the embodiments of a mobile
communication system to which the present invention is applied will
be described in detail.
[0055] [1. Network Configuration]
[0056] To begin with, the network configuration in the present
embodiments will be described with reference to FIG. 1. FIG. 1 is a
diagram for illustrating the overall scheme of a mobile
communication system 1 when the present invention is applied. As
shown in this figure, in the mobile communication system, an access
network A and an access network B are connected to a core network.
Here, access network A and access network B are assumed to be
different networks; for example, access network A is assumed to be
a 3GPP standardized network while access network B is assumed to be
a non-3GPP network (e.g., DSMIPv6) as an example.
[0057] First, a UE 10 (mobile station: User Equipment) is connected
to the core network via a plurality of radio access networks.
Access network A includes a base station (eNB 50) to which UE 10
connects and is connected to the core network via a gateway (SGW
40).
[0058] The core network is installed with a GW (PGW 20) that
forwards the communication data transmitted from other mobile
stations to a mobile station and is connected to SGW 40. Further,
the core network is installed with a management apparatus (MME 30)
that receives a request for transfer path establishment from UE 10
and takes control of the procedure for establishing a bearer (EPS
bearer) as a transfer path between UE 10 and PGW 20 via eNB 50 and
SGW 40. The EPS bearer is a QoS-supporting transfer path between UE
10 and PGW 20 by way of access network A.
[0059] Access network B is installed with an access router (AR 60)
to which UE 10 connects, so that UE 10 is connected with PGW 20 in
the core network via AR 60 by establishing a transfer path based on
DSMIPv6.
[0060] Access network A is, for example a LTE (Long Term Evolution)
as a radio access network that is defined by 3GPP as a
communication standardization organization for mobile phone
networks. Access network B is an access network such as a radio
LAN, WiMAX or the like. The core network is based on SAE (System
Architecture Evolution) defined by 3GPP.
[0061] As above, in the mobile communication system using packet
communication in the present embodiment, UE 10 is connected to the
core network by the transfer path of the bearer that supports QoS
via access network A and by the transfer path based on DSMIPv6 via
access network B.
[0062] [2. Equipment Configurations]
[0063] Subsequently, each apparatus configuration will be briefly
described with reference to the drawings. Here, SGW 40, MME 30, eNB
50 and AR 60 have the same configurations as those of the
conventional equipment in SAE, so that detailed description is
omitted.
[0064] [2.1 UE Configuration]
[0065] First, the configuration of UE 10 as a mobile station will
be described using a block diagram in FIG. 2. Here, as a specific
example of UE 10, a terminal such as mobile terminal, PDA or the
like, which simultaneously connects to the core network via a
plurality of access networks, is supposed.
[0066] As shown in FIG. 2, UE 10 includes a controller 100, a first
transceiver 110, a second transceiver 120, a storage 130, a bearer
establishment processor 140, a DSMIPv6 processor 150 and a packet
transceiver 160.
[0067] Controller 100 is a functional unit for controlling UE 10.
Controller 100 reads out and executes various programs stored in
storage 130 to realize processes.
[0068] First transceiver 110 and second transceiver 120 are
functional units for enabling UE 10 to access each access network.
First transceiver 110 is the functional unit for connection to
access network A and second transceiver 120 is the functional unit
for connection to access network B. Connected to first transceiver
110 and second transceiver 120 are external antennas,
respectively.
[0069] Storage 130 is a functional unit for storing programs, data,
etc., necessary for UE 10 to perform various kinds of operations.
Storage 130 further stores a flow management table 132 for storing
flow information for identifying applications in association with
transfer paths for transmission. This flow management table 132 is
referred to when packet transceiver 160 transmits data so as to
select a transfer path for each flow, whereby the data is
transmitted from the transceiver corresponding to the transfer
path.
[0070] Here, FIG. 4(a) shows one data configuration example of the
flow management table. As shown in FIG. 4(a), a flow (e.g., "flow 1
(TFT1, FlowID1)" is stored corresponding to a transfer path (e.g.,
"DSMIPv6 transfer path").
[0071] Bearer establishment processor 140 is a functional unit that
executes a process for establishing an EPS bearer as a
communication path to PGW 20 via access network A, by way of SGW
40.
[0072] DSMIPv6 processor 150 is a functional unit for establishing
a transfer path based on DSMIPv6 to connect to the core network via
access network B. Packet transceiver 160 is a functional unit that
transmits and receives specific data (packets). The unit decomposes
the data received from the upper layer into packets to be
transmitted. The unit also realizes a function of transferring
received packets to the upper layer.
[0073] [2.2 PGW Configuration]
[0074] Next, the configuration of PGW 20 in the present embodiments
will be described based on FIG. 3. PGW 20 includes a controller
200, a transceiver 210, a storage 230, a bearer establishment
processor 240, a DSMIPv6 processor 250 and a packet transceiver
260.
[0075] Transceiver 210 is a functional unit that is wired to a
router or a switch to transmit and receive packets. For example,
this unit performs transmission and reception using Ethernet
(registered trademark) that is usually used as a network connecting
system, or the like.
[0076] Storage 230 is a functional unit for storing programs, data,
etc., necessary for PGW 20 to execute various operations. Storage
230 further stores a flow management table 232 for storing flow
information for identifying applications in association with
transfer paths for transmission. Flow management table 232 is
referred to when packet transceiver 260 transmits data so as to
select a transfer path for each flow, whereby the data is
transmitted from the transceiver corresponding to the transfer
path.
[0077] Here, FIG. 4(b) shows one data configuration example of the
flow management table. As shown in FIG. 4(b), a flow (e.g., "flow 1
(TFT1, FlowID1)" is stored corresponding to a transfer path (e.g.,
"DSMIPv6 transfer path").
[0078] Bearer establishment processor 240 is a functional unit that
executes a process for establishing an EPS bearer as a
communication path to UE 10 via access network A, by way of SGW
40.
[0079] DSMIPv6 processor 250 is a functional unit for establishing
a transfer path based on DSMIPv6 to connect to UE 10 via access
network B. Packet transceiver 260 is a functional unit that
transmits and receives specific data (packets).
[0080] [3. Communication Path Establishment Procedure]
[0081] Next, in the network shown in FIG. 1, the procedures of UE
10, AR 60 and PGW 20 when UE 10 connects to the core network via
access network B to establish a DSMIPv6 communication path, will be
described using a sequence diagram in FIG. 5. Here, UE 10 transmits
and receives control information by means of second transceiver 120
connected to access network B to achieve the procedure.
[0082] (1) First, UE 10 performs an authentication procedure for
acquiring a local IP address from access network B (S100). The
procedure is executed by the combination of the procedure between
UE 10 and AR 60 and the procedure between AR 60 and PGW 20, as the
method conventionally done for DSMIPv6. AR 60 is installed in the
coverage area for UE 10, and is the AR that UE 10 connects. PGW 20
is an entity that is selected based on the information previously
held by UE 10. An authentication and access permission processes
are performed by PGW 20 or AR 60, using the profiles such as the
identification information of UE 10, the subscriber data, etc.,
based on the service policy.
[0083] (2) Then, the UE 10 that is authorized and permitted to
access is assigned a local IP address by AR 60, as in the
conventional method of DSMIPv6 (S102). The assigned local IP
address is an IPv4 or IPv6 address, and is used as CoA
(Care-of-Address) of DSMIPv6. The method of assignment is
implemented based on DHCP that is widely used in the Internet or a
stateless IP address assignment procedure.
[0084] (3) A setup process for establishing security association
for transmitting/receiving encrypted DSMIPv6 control messages
between UE 10 and PGW 20 is implemented (S104). This process is
performed based on IKEv2, EAP or the like, following the
conventional DSMIPv6 technique.
[0085] At this step, PGW 20 gives notice of an IPv6 Address or IPv6
network prefix to UE 10. UE 10 sets the assigned IPv6 address as
HoA (Home Address). When a network prefix is assigned, HoA is
generated based on that network prefix. By this procedure, UE 10
becomes able to perform a position registering process in safety,
to PGW 20, using an encrypted control message.
[0086] (4) UE 10 transmits a position register request defined in
DSMIPv6 to PGW 20 (S106). The message includes the identification
information of UE 10, HoA of UE 10 and CoA as positional
information. UE 10 can also make a request for assignment of HoA in
IPv4 address, by this message based on DSMIPv6.
[0087] Here, UE 10 transmits a position register request including
flow information for which communication is performed using a
DSMIPv6 transfer path to be generated. The flow information is
information that enables distinction between applications, and the
TFT (Traffic Flow Template) formed of an IP address, port number
and protocol number can be used.
[0088] Further, it is possible to use a flow ID as the flow
information when both UE 10 and PGW 20 share `TFTs` and `flow IDs
for identifying TFTs in advance. Further, the position register
request may include a plurality of flow information.
[0089] In the present embodiment, the request is transmitted
including flow 1 identified by TFT1 and flow 2 identified by TFT2.
For example, flow 1 may be for an application such as voice
communication and flow 2 may be for an application such as WEB
access or the like.
[0090] (5) PGW 20 establishes a DSMIPv6 transfer path and transmits
a position register response to UE 10 (S108). The position register
response includes HoA and CoA. It is also possible to assign HoA in
an IPv4 address by the request in (4) (the request at S106).
Further, the UE having received the position register response also
completes a transfer path establishment process.
[0091] (6) UE 10 and PGW 20 start data transmitting/receiving
through the established DSMIPv6 transfer path (S110). That is, in
DSMIPv6 transfer path, a path is set up between PGW 20 and UE
10.
[0092] By the steps as above, the DSMIPv6 transfer path is
established between UE 10 and PGW 20. In PGW 20, the transfer path
for transmitting flows of UE 10 is controlled by making the flows
correspondent to the transfer path established by DSMIPv6, as shown
in FIG. 4(b). Specifically, flow 1 and flow 2 are controlled so as
to be transmitted to UE 10 through DSMIPv6 transfer path.
[0093] Similarly, in UE 10, the transfer path for transmitting
flows of UE 10 is controlled by making the flows correspondent to
the transfer path established by DSMIPv6, as shown in FIG. 4(a).
Specifically, flow 1 and flow 2 are controlled so as to be
transmitted to UE 10 through DSMIPv6 transfer path. In UE 10 and
PGW 20, when packets are transmitted, packets are transmitted by
referring to the flow management table to select a transfer path
corresponding to the flow of transmission data. The same procedure
is implemented at the other end of UE 10, so that communication
between mobile stations is enabled by way of PGW 20.
[0094] Thereafter, if communication of an additional flow is wanted
through the DSMIPv6 transfer path, it is possible to perform
registration of the flow by implementing a position registering
procedure added with flow information.
[0095] [4. Handover Procedure]
[0096] Next, the procedure when a mobile station is handed over
from access network B to access network A will be described.
4.1 The First Embodiment
[0097] To being with, the first embodiment will be described with
reference to FIGS. 6 to 9.
[0098] [4.1.1 Attachment Type 1 Case]
[0099] First, description will be given with reference to FIG. 6.
As the initial state at the time of a handover, UE 10 is performing
communication of flow 1 and flow 2 through the DSMIPv6 transfer
path by way of access network B (S200). At the time of a handover,
UE 10 enters the coverage area of base station (eNB 50) of access
network A and performs a handover procedure for
transmitting/receiving the control messages by means of first
transceiver 110.
[0100] (1) Following the conventional method, UE 10 transmits a
handover request. Specifically, UE 10 sends an attach request to
MME 30 first (S202). The attach request includes identification
information on UE 10 for authenticating UE 10 and permitting
access. This also includes an access point name (APN) for
identifying the PGW 20 to be connected to.
[0101] Here, the difference from the prior art is that UE 10 can
give notice of a new attachment type, by use of an information
element of the attach request. The new attachment type represents
making a request for a handover of a specific flow that is
communicated through another access network. This indicates a
request that PGW 20 will not transmit packets to UE 10 through the
default bearer as the transfer path that is established first in
the conventional handover procedure.
[0102] On the other hand, since the conventional attach request at
the time of a handover does not perform control by a unit of flow,
all the flows that UE 10 is communicating are handed over. The
following description will be given assuming that attachment type
"1" is the new attachment type and attachment type "2" is a
conventional attach request. That is,
[0103] Attachment type 1: an attachment that represents a handover
from another access network and performing a handover of a specific
flow
[0104] Attachment type 2: an attachment that represents a handover
from another access network and performing a handover of all the
flows.
[0105] As a specific method of notifying the attachment type, a new
flow handover flag (which will be referred to hereinbelow as "F
flag") is defined in the attach request such that setting "F flag"
"ON" can indicate attachment type "1" and setting "F flag" "OFF"
can indicate attachment type "2". First, FIG. 6 illustrates an
example where an attach request in attachment type "1" is made.
[0106] (2) MME 30 having received the attach request executes an
authentication and access permission processes by performing a
procedure between UE 10 and eNB 50, following the conventional
method (S204). MME 30 performs authentication and access permission
based on subscriber identification information and the like of UE
10 included in the attachment information.
[0107] (3) MME 30 executes an establishment process of the default
EPS bearer (EPS bearer 1) for UE 10 that was permitted to connect
(S206). The procedure is performed following the conventional
procedure, by transmitting/receiving control messages between UE
10, eNB 50, MME 30, SGW 40 and PGW 20.
[0108] Specifically, MME 30 having received an attach request,
transmits a default EPS bearer establishment request to PGW 20. PGW
20, as receiving the default EPS bearer establishment request,
executes a process of establishing an EPS bearer. Herein, the
difference from the prior art is that the default EPS bearer
establishment request includes the attachment type (attachment type
"1" in this case) included in the attach request. Here, the default
EPS bearer is not a transfer path that satisfies the QoS level
required by the specific flow but a transfer path for enabling
communication between UE 10 and PGW 20.
[0109] (4) After establishment of the default EPS bearer, UE 10
transmits a specific EPS bearer establishment request to MME 30
(S208). The message herein includes, as the information on a flow
to be handed over, flow identification information and its QoS
level. The flow identification information is information that
enables identification of the application and can use the TFT
(Traffic Flow Template) formed of an IP address, port number and
protocol number. It is also possible to use the flow ID as the flow
information when both UE 10 and PGW 20 have shared flow IDs
identifying TFTs in advance. With this, UE 10 gives notice of the
flow for which a handover is demanded and the QoS level
corresponding to the flow (the QoS level to be guaranteed for the
flow). In the present embodiment, as the TFT included in the flow
identification information, "TFT1" is specified.
[0110] (5) MME 30 receives the specific EPS bearer establishment
request from UE 10 and executes an establishment process of a
specific EPS bearer (EPS bearer 2) (S210). The procedure for the
EPS bearer establishment process is executed following the
conventional procedure, by transmitting a specific EPS bearer
establishment request from MME 30 to PGW 20 and then
transmitting/receiving control messages between UE 10, eNB 50, MME
30, SGW 40 and PGW 20. The specific EPS bearer is a transfer path
that guarantees the QoS level required for the specific flow
requested by UE 10 and a transfer path for enabling communication
between UE 10 and PGW 20.
[0111] (6) PGW 20 transmits a flow (TFT1) selected by the request
of UE 10 from the flows of UE 10 having been transmitted through
the DSMIPv6 transfer path, by the transfer path of EPS bearer 2, to
UE 10. That is, for the selected flow (TFT1) a path is set up in
EPS bearer 2 so that data transmission/reception of TFT1 is started
by use of the transfer path of EPS bearer 2 (S212).
[0112] As described above, though in the conventional handover, in
performing a handover it was necessary to perform a handover once
to the default EPS bearer that does not satisfies the QoS level, it
is possible to perform a handover to the specific EPS bearer that
guarantees the QoS level necessary for the flow, without using the
default EPS bearer. Accordingly, it becomes possible to switch the
transfer path without degrading communication quality in the
application.
[0113] Specifically, UE 10 transmits a specific EPS bearer
establishment request by specifying flow 1 (TFT1) to establish EPS
bearer 2 that guarantees the QoS level of flow 1. FIG. 7(a) shows a
flow management table 132 of UE 10 in this case. FIG. 7(b) shows a
flow management table 132 of PGW 20. In this way, the transfer path
of flow 1 is updated to EPS bearer 2 in UE 10, and the transfer
path of flow 1 is updated to EPS bearer 2 in PGW 20.
[0114] In transmitting packets, in UE 10 and PGW 20, packets are
transmitted by identifying the flow based on the transmission data
with reference to the flow management table so as to select the
transfer path corresponding to the flow. On the other hand, flow 2
that is not included in the specific EPS bearer establishment
request is kept communicating through the DSMIPv6 transfer
path.
[0115] (7) After establishment of the specific EPS bearer UE 10
transmits a position register request to PGW 20, based on DSMIPv6
(S214). The message includes the identification information of UE
10, HoA of UE 10 and CoA as positional information. Further, UE 10
transmits the flow information for performing communication using
the established DSMIPv6 transfer path, with the position register
request.
[0116] (8) PGW 20 transmits a position register response to UE 10
to complete the position registering process of DSMIPv6 (S216).
[0117] As a result of the above procedure, it becomes possible to
perform a handover of a unit of flow from access network B to
access network Awhile keeping the QoS. In the prior art, when a
plurality of flows proceed in communication, all the flows have to
be handed over at once. Hence it was impossible to select an access
network (transfer path) suited to each of the flows.
[0118] Accordingly, as a result of the present embodiment, for
example an access network having a large enough bandwidth is
selected for a flow that needs a greater bandwidth while other
access networks are allotted to other flows, whereby it is possible
to make use of transmission path more suited to flow, and hence use
resources efficiently.
[0119] Here, though it was assumed that switching of transfer paths
at PGW 20 is implemented immediately after establishment of the
specific EPS bearer at S210, the switching may also be triggered by
the position registering procedure of DSMIPv6 shown at S214 and
S216.
[0120] Further, though description was made that the position
register request/response are given after establishment of the
specific EPS bearer (EPS bearer 2), position register complete
notice/response from PGW 20 to UE 10 may also be given. That is,
PGW 20 transmits a position register complete notice that indicates
that position registration of UE 10 after a handover is completed,
to UE 10. UE 10 transmits a response signal that acknowledges the
reception of the position register complete notice, to PGW 20.
Further, switching of transfer paths at PGW 20 may be triggered by
the position register complete notice/response procedure from PGW
20 to UE 10.
[0121] [4.1.2 Attachment Type 2 Case]
[0122] Subsequently, a case when the attachment type is "2" will be
described with reference to FIG. 8.
[0123] As the initial state at the time of a handover, UE 10 is
performing communication of flow 1 (TFT1) and flow 2 (TFT2) through
the DSMIPv6 transfer path by way of access network B (S300) as a
result of the communication path establishment procedure described
heretofore. At the time of a handover, UE 10 enters the coverage
area of base station (eNB 50) of access network A and transmits a
handover request by a control message using first transceiver 110
to execute a handover procedure.
[0124] (1) UE 10 transmits an attach request as a handover request
to MME 30, following the conventional method (S302). The attach
request includes identification information on UE 10 for
authenticating UE 10 and permitting access. This also includes an
access point name (APN) for identifying the PGW 20 to be connected
to. Here, UE 10 makes an attach request as attachment type "2" by
non-inclusion of F-flag.
[0125] (2) Similarly to (2) for attachment type "1", an
authentication and access permission processes are executed
(S304).
[0126] (3) Similarly to (3) for attachment type "1", MME 30
executes an establishment process of the default EPS bearer (EPS
bearer 1) for UE 10 that was permitted to connect (S306). Thereby,
the default EPS bearer (EPS bearer 1) is establishment between UE
10 and PGW 20. That is, MME 30 having received the attach request,
transmits a default EPS bearer establishment request to PGW 20. The
default EPS bearer establishment request includes the attachment
type (attachment type "2" in this case) included in the attach
request.
[0127] (4) Since the attach type is "2", the paths for flow 1 and
flow 2 are set up for PGW 20 by way of EPS bearer 1. That is, data
transmission/reception of flow 1 and flow 2 (TFT1 and TFT2) is
started in EPS bearer 1 (S308).
[0128] (5) UE 10 transmits a position register request to PGW 20
after establishment of the specific EPS bearer (S310).
[0129] (6) PGW 20 transmits a position register response to UE 10
to complete the position registering process (S312).
[0130] (7) After establishment of the default EPS bearer, UE 10
transmits a specific EPS bearer establishment request to MME 30
(S314). The message herein is adapted to include, as the
information on the flow, flow identification information and QoS
level. In the present embodiment, as the TFT included in the flow
identification information, "TFT1" is specified.
[0131] (8) MME 30 receives the specific EPS bearer establishment
request from UE 10 and executes an establishment process of a
specific EPS bearer (EPS bearer 2) (S316). The procedure is
performed following the conventional procedure, by
transmitting/receiving of control messages between UE 10, eNB 50,
MME 30, SGW 40 and PGW 20.
[0132] (9) PGW 20 transmits a flow (TFT1) selected by the request
of UE 10 from the flows of UE 10 having been transmitted and
received through EPS bearer 1, to UE 10 through the transfer path
of EPS bearer 2. Thereby, a path for TFT1 is set up in EPS bearer 2
so that data transmission/reception of TFT1 is started by use of
the transfer path of EPS bearer 2 (S318).
[0133] In this way, according to the present embodiment, by setting
the attachment type to be "2", it is possible to implement a
similar process even if the process is a conventional one in which
all the flows are transferred once to the default EPS bearer,
followed by transfer to the specific EPS bearer.
[0134] [4.1.3 Processing Flow in Control Station]
[0135] Referring now to an operation flow in FIG. 9, the processing
in the control station (PGW 20) accompanied by bearer
establishment, in the present embodiment will be described.
[0136] First, a default EPS bearer establishment request is
received (Step S10). In the present embodiment, MME 30 receives an
attach request from UE 10 first. MME 30 gives notice of a default
EPS bearer establishment request to PGW 20 as the procedure for
establishing the default EPS bearer. At this time, the attachment
type included in the default EPS bearer establishment request is
retained. The default EPS bearer is established in response to this
default EPS bearer establishment request so as to establish a
transfer path (EPS bearer 1) between PGW 20 and UE 10 (Step
S12).
[0137] Then, the attachment type indicated by the default EPS
bearer establishment request is identified (Step S14).
[0138] Here, when the attachment type is "1" (Step S14; attachment
type "1"), MME 30 waits for an establishment request for a specific
EPS bearer (Step S16). Then, when receiving a specific EPS bearer
establishment request from UE 10 (Step S16; Yes), MME 30
establishes a specific EPS bearer (EPS bearer 2) that guarantees
QoS (Step S18). Then, PGW 20 sets up a flow path (route) designated
by the specific EPS bearer establishment request and starts
communication (Step S20).
[0139] On the other hand, when the attachment type is "2" in Step
S14 (Step S14; attachment type "2"), PGW 20 sets up a flow path
(route) on the default EPS bearer and starts communication (Step
S22).
[0140] In this way, when the attachment type is "2", PGW 20
transmits all the flows of UE 10 that have been transmitted to the
DSMIPv6 transfer path, to UE 10 through the specific EPS bearer
(EPS bearer 1).
[0141] However, this is the same as the conventional handover; even
when the flow of UE 10 to be handed over needs a QoS level,
communication is performed through the default bearer that does not
satisfy the QoS level corresponding to the flow. That is, the flow
is transmitted through the transfer path that does not satisfy the
necessary quality depending on the application, hence there is a
risk of the quality being markedly deteriorated.
[0142] In this case, by setting the attachment type to be "1", it
is possible to hand over the flow from the DEMIPv6 transfer path to
the specific EPS bearer (EPS bearer 2) that is able to guarantee
the QoS level without use of the default EPS bearer.
4.2 The Second Embodiment
[0143] Next, the second embodiment will be described with reference
to FIG. 10. The network configuration and apparatus configuration
of this embodiment are the same as those of the first embodiment,
so that detailed description is omitted. Further, since the
procedures in which UE 10 connects to a core network via access
network B and establishes the DSMIPv6 transfer path for flow 1 and
flow 2 are also the same, the description is omitted.
[0144] As the initial state at the time of a handover, UE 10 is
performing communication of flow 1 and flow 2 through the DSMIPv6
transfer path by way of access network B. At the time of a
handover, UE 10 enters the coverage area of eNB 50 of access
network A and transmits a handover request by a control message
using first transceiver 110 to execute a handover procedure. This
handover procedure is the same as the handover procedure described
in the first embodiment with reference to FIG. 6 up to the stage
where the default EPS bearer is established, or S206. The procedure
that follows will be described with reference to FIG. 10.
[0145] (1) Differing from the first embodiment, UE 10 transmits a
position register request for DSMIPv6 to PGW 20. This position
register request demands establishment of a specific EPS bearer
(S350). Here, the message of this position register request should
include the identification information of UE 1, HoA of UE 10 and
CoA as the positional information. Further, UE 10 transmits a
position register request including the flow information and a QoS
level for performing communication through the DSMIPv6 transfer
path to be generated.
[0146] (2) PGW 20 having received the position register request
implements a process of establishing a specified EPS bearer (EPS
bearer 2) (S352). The procedure is performed following the
conventional procedure, by transmitting/receiving control messages
between UE 10, eNB 50, MME 30, SGW 40 and PGW 20. The specific EPS
bearer is a transfer path that guarantees the QoS level required
for the specific flow requested by UE 10 and a transfer path for
enabling communication between UE 10 and PGW 20.
[0147] (3) PGW 20 and UE 10 set up a path for communication of the
flow (TFT1 in the present embodiment) present in the position
register request. By this setup, the DSMIPv6 transfer path is
switched to the specific EPS bearer transfer path to start
communication (S354). Communication of the flows other than this is
continued through the DSMIPv6 transfer path.
[0148] (4) After establishment of the specific EPS bearer, PGW 20
transmits a position register response to UE 10 (S356).
[0149] Updating of flow management table 132 of UE 10 and flow
management table 232 of PGW 20 and the procedure of switching
transfer paths may be done when the specific EPS bearer is
established similarly to the first embodiment, or may also be done
when the position registering process of DSMIPv6 is completed.
[0150] The difference of the present embodiment from the above
first embodiment is that in the first embodiment MME 30 takes
control of performing establishment of the specific EPS bearer
based on the specific EPS bearer establishment request of UE 10
whereas in the present embodiment PGW 20 takes control of
establishment based on the position register request of
DSMIPv6.
4.3 The Third Embodiment
[0151] Next, the third embodiment will be described. The network
configuration and apparatus configuration of this embodiment are
the same as those of the first embodiment, so that detailed
description is omitted. Further, since the procedures in which UE
10 connects to a core network via access network B and establishes
the DSMIPv6 transfer path for flow 1 and flow 2 are also the same,
the description is omitted.
[0152] As the initial state at the time of a handover, UE 10 is
performing communication of flow 1 and flow 2 through the DSMIPv6
transfer path by way of access network B. At the time of a
handover, UE 10 enters the coverage area of eNB 50 of access
network A and transmits a handover request by a control message
using first transceiver 110 to execute a handover procedure. The
handover procedure in the present embodiment will be described with
reference to FIG. 11.
[0153] (1) Initially, UE 10 and PGW 20 are transmitting/receiving
data for flow 1 (TFT1) and flow 2 (TFT2) through the DSMIPv6
transfer path (S400).
[0154] (2) Then, an attach request is transmitted from first
transceiver 110 of UE 10 to MME 30 (S402). The difference from the
first embodiment is that UE 10 requests an authentication process
alone by attachment type "1" in link with attachment and notifies
that there is no need of establishment of the default EPS bearer.
Thereby, MME 30 performs an authentication procedure as receiving
the attach request but do not perform a procedure of establishing
the default EPS bearer.
[0155] (3) MME 30 having received the attach request, performs an
authentication and access permission processes by the procedure
between UE 10 and eNB 50 following the conventional method (S406).
MME 30 performs the authentication and access permission processes
based on the subscriber identification information and the like of
UE 10 included in the attach request. Thereafter, MME 30 waits for
receiving a specific EPS bearer establishment request from UE
10.
[0156] (4) When permitted to access, UE 10 transmits a specific EPS
bearer establishment request to MME 30 (S408). Here, the message of
the specific EPS bearer establishment request is transmitted
including, as the information on the flow, flow identification
information (TFT1) and QoS level.
[0157] Thereby, an EPS bearer establishment process is implemented
(S410) so that a specific EPS bearer (EPS bearer 2) is established
between UE 10 and PGW 20. Then, a path is set up on the established
EPS bearer 2 so that transmitting/receiving of "TFT1" data is
started (S412).
[0158] Further, similarly to S214 and S216 in the first embodiment,
position register request and response are transmitted/received
(S414 and S416). Updating of the flow management table and
switching of transfer paths and other procedures after
establishment of the specific EPS bearer are the same as those in
the above embodiment, so that description is omitted.
[0159] The difference of the third embodiment from the first
embodiment is that upon the attach request (S402) at the timing of
a handover, only the authentication process is carried out without
establishment of the default EPS bearer and then UE 10 transmits a
specific EPS bearer establishment request. Thereby, it is possible
to complete a handover more quickly without the need of
establishing the default EPS bearer (EPS bearer 1), compared to the
first embodiment.
[0160] Also, in the present embodiment, instead of requesting
establishment of a specific EPS bearer by notifying the flow
information and QoS level upon specific EPS bearer establishment
request, the flow information and QoS level may be added so as to
establish a specific EPS bearer, at the time of PSMIPv6 position
register request, similarly to the second embodiment.
[0161] Further, it goes without saying that it is possible to
perform a handover procedure in a conventional manner as in the
first embodiment when an attach request is made by attachment type
"2".
[0162] Moreover, though description was made that the position
register request/response are given after establishment of the
specific EPS bearer (EPS bearer 2), position register complete
notice/response from PGW 20 to UE 10 may also be given. That is,
PGW 20 transmits a position register complete notice that indicates
that position register of UE 10 after handover is completed, to UE
10. UE 10 transmits a response signal that acknowledges the
reception of the position register complete notice, to PGW 20.
Further, switching of transfer paths at PGW 20 may be triggered by
the position register complete notice/response procedure from PGW
20 to UE 10.
4.4 The Fourth Embodiment
[0163] Next, the fourth embodiment will be described. The network
configuration and apparatus configuration of this embodiment are
the same as those of the first embodiment, so that detailed
description is omitted. Further, since the procedures in which UE
10 connects to a core network via access network B and establishes
the DSMIPv6 transfer path for flow 1 and flow 2 are also the same,
the description is omitted.
[0164] As the initial state at the time of a handover, UE 10 is
performing communication of flow 1 and flow 2 through the DSMIPv6
transfer path by way of access network B. At the time of a
handover, UE 10 enters the coverage area of eNB 50 of access
network A and transmits a handover request by a control message
using first transceiver 110 to execute a handover procedure. Here,
the procedure in the fourth embodiment will be described with
reference to FIG. 12.
[0165] (1) Initially, UE 10 and PGW 20 are transmitting/receiving
data for flow 1 (TFT1) and flow 2 (TFT2) through the DSMIPv6
transfer path (S500).
[0166] (2) Then, UE 10 transmits an attach request to MME 30
(S502). Here, the attach request of the present embodiment includes
identification information on UE 10 for authenticating UE 10 and
permitting access. The difference from the first embodiment is that
the attach request is transmitted with inclusion of the information
("TFT1" to be handed over and QoS level) on the flow to be handed
over.
[0167] (3) MME 30 having received the attach request, performs an
authentication and access permission processes by the procedure
between UE 10 and eNB 50 following the conventional method (S504).
Specifically, MME 30 having received an attach request, transmits a
default EPS bearer establishment request to PGW 20. PGW 20, as
receiving the default EPS bearer establishment request, executes a
process of establishing an EPS bearer. Here, the default EPS bearer
establishment request includes information on the flow to be handed
over, included in the attach request.
[0168] (4) MME 30 implements a process of establishing a specific
EPS bearer to UE 10 that was permitted to connect, similarly to
S410 in FIG. 11 for the third embodiment (S506).
[0169] Thereby, a specific EPS bearer (EPS bearer 2) is established
between UE 10 and PGW 20. Then, a path is set up on the established
EPS bearer 2 so that data transmission/reception of "TFT1" is
started (S508).
[0170] Further, similarly to S214 and S216 in the first embodiment,
position register request and response are transmitted/received
(S510 and S512). Updating of the flow management table and
switching of transfer paths and other procedures after
establishment of the specific EPS bearer are the same as those in
the above embodiment, so that description is omitted.
[0171] The difference of the present embodiment from the first
embodiment is that in the first embodiment the default EPS bearer
is established first at the time of a handover, then the specific
EPS bearer is established, whereas in the fourth embodiment the
specific EPS bearer can be established by the attach request.
Thereby, the procedure of establishing the default EPS bearer is
omitted so that it is possible to complete a handover more quickly,
compared to the first embodiment.
[0172] Also, in the present embodiment, instead of requesting
establishment of a specific EPS bearer by notifying the flow
information and QoS level upon specific EPS bearer establishment
request, the flow information and QoS level may be added so as to
establish a specific EPS bearer, at the time of PSMIPv6 position
register request, similarly to the second embodiment.
[0173] Further, if the attach request includes no flow information
and QoS level, the conventional handover procedure can be carried
out.
[0174] Moreover, in the present embodiment, though description was
made that the position register request/response are given after
establishment of the specific EPS bearer (EPS bearer 2), position
register complete notice/response from PGW 20 to UE 10 may also be
given. That is, PGW 20 transmits a position register complete
notice that indicates that position register of UE 10 after
handover is completed, to UE 10. UE 10 transmits a response signal
that acknowledges the reception of the position register complete
notice, to PGW 20. Further, switching of transfer paths at PGW 20
may be triggered by the position register complete notice/response
procedure from PGW 20 to UE 10.
DESCRIPTION OF REFERENCE NUMERALS
[0175] 1 mobile communication system [0176] 10 UE [0177] 100
controller [0178] 110 first transceiver [0179] 120 second
transceiver [0180] 130 storage [0181] 132 flow management table
[0182] 140 bearer establishment processor [0183] 150 DSMIPv6
processor [0184] 160 packet transceiver [0185] 20 PGW [0186] 200
controller [0187] 210 transceiver [0188] 230 storage [0189] 232
flow management table [0190] 240 bearer establishment processor
[0191] 250 DSMIPv6 processor [0192] 260 packet transceiver [0193]
30 MME [0194] 40 SGW [0195] 50 eNB [0196] 60 AR
* * * * *