U.S. patent number 9,271,202 [Application Number 13/340,148] was granted by the patent office on 2016-02-23 for handover control method, apparatuses and communication system.
This patent grant is currently assigned to Huawei Technologies Co., Ltd.. The grantee listed for this patent is Li Chai, Bo Lin, Yan Wang, Tao Zhang. Invention is credited to Li Chai, Bo Lin, Yan Wang, Tao Zhang.
United States Patent |
9,271,202 |
Zhang , et al. |
February 23, 2016 |
Handover control method, apparatuses and communication system
Abstract
A handover control method, apparatuses and a communication
system are disclosed. In embodiments of the present invention, a
control base station (DeNB) of a Relay node is identified according
to an established relation between the Relay node and the Control
base station, and therefore, a handover request message can be
routed to the correct DeNB and finally sent to the RN, and a User
Equipment can normally hand over to a cell controlled by the Relay
node.
Inventors: |
Zhang; Tao (Beijing,
CN), Lin; Bo (Beijing, CN), Wang; Yan
(Beijing, CN), Chai; Li (Beijing, CN) |
Applicant: |
Name |
City |
State |
Country |
Type |
Zhang; Tao
Lin; Bo
Wang; Yan
Chai; Li |
Beijing
Beijing
Beijing
Beijing |
N/A
N/A
N/A
N/A |
CN
CN
CN
CN |
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Assignee: |
Huawei Technologies Co., Ltd.
(Shenzhen, CN)
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Family
ID: |
43391818 |
Appl.
No.: |
13/340,148 |
Filed: |
December 29, 2011 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20120100855 A1 |
Apr 26, 2012 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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PCT/CN2010/073674 |
Jun 8, 2010 |
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Foreign Application Priority Data
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Jun 29, 2009 [CN] |
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2009 1 0142291 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L
12/56 (20130101); H04W 36/0061 (20130101); H04B
7/155 (20130101); H04B 7/2606 (20130101); H04W
40/24 (20130101); H04L 45/26 (20130101); H04W
92/12 (20130101); H04W 36/38 (20130101); H04W
92/20 (20130101); H04W 40/36 (20130101); H04W
36/10 (20130101); H04W 36/08 (20130101); H04W
84/047 (20130101) |
Current International
Class: |
H04B
7/14 (20060101); H04W 36/00 (20090101); H04B
7/155 (20060101); H04B 7/26 (20060101); H04L
12/54 (20130101); H04L 12/721 (20130101); H04W
40/24 (20090101); H04W 36/38 (20090101); H04W
40/36 (20090101); H04W 84/04 (20090101); H04W
92/12 (20090101); H04W 92/20 (20090101); H04W
36/08 (20090101); H04W 36/10 (20090101) |
Field of
Search: |
;370/203,204-215,229-240,310-337,338-350,351-394,395.1,395.3,395.4,395.41,395.42,395.5,395.52,431-457,458-463,464-497,498-529 |
References Cited
[Referenced By]
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Foreign Patent Documents
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JP |
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WO |
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WO |
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Other References
Third Office Action of Chinese Application No. 200910142291.7
mailed May 20, 2013, 6 pages (Partial Translation). cited by
applicant .
Russian Office Action received on U.S. Pat. No. 2012103013, mailed
Jun. 17, 2013, 29 pages. cited by applicant .
Russian Office Action received in Application No. 2012103013/07,
Applicant: Huawei Technologies Co., Ltd., mailed Apr. 9, 2013, 15
pages. cited by applicant .
Texas Instruments, "On the design of relay node for LTE-advanced,"
3GPP TSG RAN WG1 #56, R1090593, Athens, Greece, Feb. 9-13, 2009, 11
pages. cited by applicant .
Extended European Search Report received in Application No.
10793547.0-1525, Applicant: Huawei Technologies Co., Ltd., mailed
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TS 36.300 v9.0.0, Jun. 2009, 157 pages. cited by applicant.
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Primary Examiner: Liu; Jung-Jen
Attorney, Agent or Firm: Slater & Matsil, L.L.P.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of International Application No.
PCT/CN2010/073674, filed on Jun. 8, 2010, which claims priority to
Chinese Patent Application No. 200910142291.7, filed on Jun. 29,
2009, both of which are hereby incorporated by reference in their
entireties.
Claims
What is claimed is:
1. A handover control method, comprising: receiving, by a serving
base station, a measurement report from a user equipment which is
to be handed over from a source cell served by the serving base
station to a target cell served by a relay node, wherein the
measurement report comprises a physical cell identity (PCI) of the
target cell and an evolved-universal terrestrial radio access
network (E-UTRAN) cell global identifier (ECGI) of the target cell;
obtaining, by the serving base station, an identity of the relay
node from the ECGI of the target cell, wherein the identity of the
relay node is same as an identity of a control base station which
controls the relay node, and the ECGI of the target cell comprises
the identity of the relay node; sending, by the serving base
station, a handover request to the control base station identified
by the identity of the relay node, wherein the handover request
comprises an identity of the target cell; and sending, by the
control base station, the handover request to the relay node
corresponding to the identity of the target cell.
2. The method according to claim 1, further comprising before the
control base station sending the handover request to the relay
node: finding, by the control base station, the relay node
according to the identity of the target cell.
3. The method according to claim 2, wherein the identity of the
target cell comprises at least one of the ECGI of the target cell
and the PCI of the target cell.
4. The method according to claim 2, wherein the finding, by the
control base station, the relay node comprises: searching, by the
control base station, the identity of the target cell in a list of
one or more cell identities for one or more cells that are served
by the relay node to obtain the relay node that serves the target
cell, wherein the list is received by the control base station from
the relay node.
5. The method according to claim 1, further comprising: allocating,
by the control base station, the identity of the control base
station as the identity of the relay node to the relay node when
the relay node accesses the control base station.
6. A handover control method, comprising: receiving, by a serving
base station, a measurement report from a user equipment which is
to be handed over from a source cell served by the serving base
station to a target cell served by a relay node, wherein the
measurement report comprises a physical cell identity (PCI) of the
target cell and an evolved-universal terrestrial radio access
network (E-UTRAN) cell global identifier (ECGI) of the target cell;
obtaining, by the serving base station, an identity of the relay
node from the ECGI of the target cell, wherein the identity of the
relay node is same as an identity of a control base station which
controls the relay node and the ECGI of the target cell comprises
the identity of the relay node; and sending, by the serving base
station, a handover request to the control base station identified
by the identity of the relay node, wherein the handover request
comprises an identity of the target cell.
7. The method according to claim 6, wherein the identity of the
target cell comprises at least one of the ECGI of the target cell
and the PCI of the target cell.
8. A base station comprising a processing hardware platform
executing instructions stored on a non-transitory computer-readable
storage medium to perform functions as a plurality of modules,
wherein in a situation where the base station serves as a serving
base station of a user equipment which is to be handed over from a
source cell that is served by the base station to a target cell
that is served by a relay node, the plurality of modules
comprising: an obtaining module, configured to obtain a physical
cell identity (PCI) of the target cell and an evolved-universal
terrestrial radio access network (E-UTRAN) cell global identifier
(ECGI) of the target cell from a measurement report received from
the user equipment, and obtain an identity of the relay node,
wherein the identity of the relay node is same as an identity of a
control base station which controls the relay node, and the ECGI of
the target cell comprises the identity of the relay node; and a
handover request sending module, configured to cause a handover
request to be transmitted to the control base station identified by
the identity of the relay node, wherein the handover request
comprises the identity of the target cell.
9. The base station according to claim 8, wherein the identity of
the target cell comprises at least one of the ECGI of the target
cell and the PCI of the target cell.
10. A communication system, comprising: a first base station, and a
second base station controlling a relay node, wherein in a
situation where the user equipment is to be handed over from a
source cell that is served by the first base station to a target
cell that is served by the relay node: the first base station is
configured to: receive a measurement report from the user
equipment, obtain an identity of the relay node from an
evolved-universal terrestrial radio access network (E-UTRAN) cell
global identifier (ECGI) of the target cell, and send a handover
request to the second base station identified by the identity of
the relay node, wherein the measurement report comprises a physical
cell identity (PCI) of the target cell and the ECGI of the target
cell, the identity of the relay node is same as an identity of the
second base station, and the handover request comprises an identity
of the target cell; the second base station is configured to
receive the handover request from the first base station, and send
the handover request to the relay node corresponding to the
identity of the target cell.
11. The system according to claim 10, wherein the second base
station is further configured to before sending the handover
request to the relay node: find the relay node according to the
identity of the target cell.
12. The system according to claim 11, wherein the second base
station is configured to find the relay node according to the
identity of the target cell as follows: searching the identity of
the target cell in a list of one or more cell identities for one or
more cells that are served by the relay node to obtain the relay
node that serves the target cell, wherein the list is received by
the second base station from the relay node.
13. The communication system according to claim 10, wherein the
identity of the target cell comprises at least one of the ECGI of
the target cell and the PCI of the target cell.
14. A machine comprising: a processor executing instructions to
perform functions as a plurality of modules, wherein the plurality
of modules comprises: an obtaining module, configured to obtain,
from a measurement report received from a user equipment, a
physical cell identity (PCI) of a target cell and an
evolved-universal terrestrial radio access network (E-UTRAN) cell
global identifier (ECGI) of the target cell to which the user
equipment is to be handed over from a source cell that is served by
a serving base station, the a target cell being served by a relay
node; the obtaining module is further configured to obtain an
identity of the relay node from the ECGI of the target cell,
wherein the identity of the relay node is same as an identity of a
control base station which controls the relay node, and the ECGI of
the target cell comprises the identity of the relay node; and a
controlling module, configured to cause a handover request to be
transmitted to the control base station, wherein the handover
request comprises an identity of the target cell.
Description
FIELD OF THE INVENTION
The present invention relates to the field of communication
technologies, and in particular, to a handover control method,
apparatuses, and a communication system.
BACKGROUND OF THE INVENTION
Beyond Third Generation mobile communication system (Beyond Third
Generation mobile communication system, B3G) is named International
Mobile Telecommunications Advanced (IMT-Advanced) by the
International Telecommunication Union Radio (International
Telecommunication Union Radio, ITU-R). The IMT-Advanced imposes
high requirements on the system capacity. Nevertheless, the
high-bandwidth spectrum that supports the high capacity of the
IMT-Advanced is generally available in higher bands, but higher
bands involve great path loss and penetration loss, and can hardly
achieve good coverage.
To meet the requirements of the IMT-Advanced with respect to system
capacity and coverage, the prior art introduces a relay technology
to improve the system capacity and coverage. In a traditional
network, the wireless connection between a base station and a User
Equipment is a direct wireless connection, which forms a single-hop
network. The relay technology is intended to add one or more relays
between the base station and the User Equipment. The relays are
responsible for processing and forwarding radio signals sent by the
base station at one or more attempts until the User Equipment
receives the radio signals. Taking the simple 2-hop relay as an
example, a radio link between base station and a User Equipment is
split into two radio links, namely, a radio link from the E-UTRAN
NodeB to a Relay Node, and a radio link from the Relay Node to the
User Equipment, thus making it possible to replace a low-quality
link with two high-quality links and achieve higher link capacity
and better coverage.
FIG. 1 shows a network topology in which the relay technology is
introduced. The network includes a Mobility Management Entity
(MME), a base station (e.g. E-UTRAN Node B, eNB), an Relay Node
(Relay Node, RN), and a control base station (e.g. Donor E-UTRAN
NodeB, DeNB) of the RN. The DeNB is also an base station, and
provides a function of controlling the RN in addition to
conventional functions of an eNB. The RN may be fixed or mobile.
When the RN is mobile, the DeNB that controls the RN is also
variable.
In FIG. 1, the interface between the MME and the eNB is S1, and the
interface between the MME and the DeNB is also S1. An X2 interface
may exist between the eNB and the DeNB or not. No direct interface
exists between the RN and the eNB. A wireless Un interface exists
between the RN and the DeNB. The coverage of the eNB and the DeNB
may be divided into multiple different cells. When a connected User
Equipment moves from a cell of the eNB to a cell of the DeNB, a
handover process will be triggered. Like the eNB and DeNB, the RN
is equivalent to an base station. The coverage of the RN may also
be divided into different cells. When a connected UE moves from a
cell of the eNB to a cell of the RN, a handover process will be
triggered.
In the process of researching and practicing the prior art, the
inventor of the present invention finds that in the prior art, when
the User Equipment (User Equipment, UE) hands over from the eNB to
the RN, the UE can interact with the RN to obtain the identity of
the RN cell (RN_PCI), and report the RN_PCI to the network.
According to the RN_PCI, the network determines the RN to which the
UE will hand over, but the network is unable to determine the
control base station that controls the RN, and unable to send a
Handover_Request message to the correct DeNB. Consequently, the
handover process cannot proceed normally.
SUMMARY OF THE INVENTION
Embodiments of the present invention provide a handover control
method, apparatuses, and a communication system to route a handover
control request to a correct DeNB and ensure the normal handover
process.
A handover control method provided in an embodiment of the present
invention includes:
obtaining an identity of a relay node corresponding to a handover
target cell of a user equipment;
obtaining an identity of control base station corresponding to the
relay node according to the identity of the relay node; and
sending a handover control request to the control base station
according to the identity of control base station, so that the
control base station notifies the relay node of performing access
control for the user equipment.
A handover control method provided in an embodiment of the present
invention includes:
receiving, by a user equipment, a broadcast message sent from a
relay node, wherein the broadcast message carries information about
a route between the relay node and a control base station on which
the relay node belongs; and
sending, by the user equipment, information about the route to an
base station to which the user equipment is currently attached, so
that the currently attached base station notifies the control base
station corresponding to the relay node to perform access control
for the user equipment according to the information about
route.
A handover control apparatus provided in another embodiment of the
present invention includes:
a relay node identity obtaining processor, configured to obtain an
identity of a Relay node corresponding to a handover target cell of
a user equipment;
a control base station identity obtaining processor, configured to
obtain a identity of control base station corresponding to the
relay node according to the identity of the relay node obtained by
the relay node identity obtaining processor; and
a handover control request sending transmitter, configured to send
a handover control request to the control base station according to
the identity of control base station obtained by the control base
station identity obtaining processor, so that the control base
station notifies the relay node of performing access control for
the user equipment.
An access control apparatus provided in another embodiment of the
present invention includes:
a receiving receiver, configured to receive a handover request
message, the handover request message comprising an identity of a
target cell of a user equipment; and
a handover controlling processor, configured to search for a relay
node that serves the target cell according to the identity of the
target cell, and notify the search Relay node of controlling access
of the user equipment.
A network relay apparatus provided in another embodiment of the
present invention includes:
an information reporting processor, configured to report an
identity of a relay node of itself and a list of served cells to a
corresponding control base station; and
an access processing processor, configured to receive a
notification from the control base station and perform access
control for a user equipment.
A network relay apparatus provided in another embodiment of the
present invention includes:
a control base station Identity obtaining processor, configured to
obtain an identity of control base station of the network relay
apparatus;
a information about the route generating processor, configured to
generate the information about the route according to the identity
of control base station and an identity of a relay node of the
network relay apparatus; and
a broadcasting processor, configured to broadcast the information
about the route generated by the information about the route
generating processor throughout cell coverage of the network relay
apparatus.
A UE provided in another embodiment of the present invention
includes:
a broadcast message receiving receiver, configured to receive a
broadcast message sent by a relay node, wherein the broadcast
message carries information about a routing relation between the
relay node and a control base station of the relay node;
a information about the route sending transmitter, configured to
send the routing relation information to an base station to which
the user equipment is currently attached, so that the base station
notifies the control base station corresponding to the relay node
of performing access control for the User equipment according to
the routing relation information.
A communication system provided in another embodiment of the
present invention includes: a handover control apparatus, an access
control apparatus, an RN, and a UE, where
the User equipment is configured to send an identity of the relay
node corresponding to a handover target cell to the handover
control apparatus, and access the target cell under control of the
relay node;
the handover control apparatus is configured to: obtain the
identity of the relay node corresponding to the handover target
cell of the user equipment, obtain an identity of control base
station corresponding to the relay node according to the identity
of the relay node, and send a handover control request to the
control base station according to the identity of control base
station;
the access control apparatus is configured to receive the handover
control request from the handover control apparatus, and notify the
relay node of performing access control for the user equipment;
and
the relay node is configured to receive the notification from the
access control apparatus, and execute the access control for the
user equipment.
In the embodiments of the present invention, the DeNB of the RN is
identified according to the relation between the RN and the DeNB,
and therefore, the Handover Request message can be routed to the
correct DeNB and finally sent to the RN, and the UE can normally
hand over to the cell controlled by the RN.
BRIEF DESCRIPTION OF THE DRAWINGS
To describe the technical solution under the present invention more
clearly, the following outlines the accompanying drawings involved
in the embodiments of the present invention. Apparently, the
accompanying drawings outlined below are not exhaustive, and
persons of ordinary skill in the art can derive other drawings from
such accompanying drawings without any creative effort.
FIG. 1 shows a network topology in which a relay technology is
introduced in the prior art;
FIG. 2 is a flowchart of a handover control method in a first
embodiment of the present invention;
FIG. 3 is a flowchart of a handover control method in a second
embodiment of the present invention;
FIG. 4 is a signaling flowchart of a first application instance in
the second embodiment of the present invention;
FIG. 4a is a schematic flowchart of a handover control method in
the second embodiment of the present invention;
FIG. 5 is a flowchart of a handover control method in a third
embodiment of the present invention;
FIG. 6 shows comparison between identity of the relay node and
control base station ID in the third embodiment of the present
invention;
FIG. 7 is a flowchart of a handover control method in a fourth
embodiment of the present invention;
FIG. 8 is a signaling flowchart of an application instance in the
fourth embodiment of the present invention;
FIG. 9 is a flowchart of a handover control method in a fifth
embodiment of the present invention;
FIG. 10 is a flowchart of a handover control method in a sixth
embodiment of the present invention;
FIG. 11 is a flowchart of a handover control method in a seventh
embodiment of the present invention;
FIG. 12 is a flowchart of a handover control method in an eighth
embodiment of the present invention;
FIG. 13 is a schematic structure diagram of a handover control
apparatus in a ninth embodiment of the present invention;
FIG. 14 is a schematic structure diagram of an access control
apparatus in a tenth embodiment of the present invention;
FIG. 15 is a schematic structure diagram of a network relay
apparatus in an eleventh embodiment of the present invention;
FIG. 16 is a schematic structure diagram of a network relay
apparatus in a twelfth embodiment of the present invention;
FIG. 17 is a schematic structure diagram of a UE in a thirteenth
embodiment of the present invention; and
FIG. 18 is a schematic structure diagram of a communication system
in a fourteenth embodiment of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
The embodiments of the present invention provide a handover control
method, apparatuses, and a communication system, as detailed
below.
Embodiment 1
As shown in FIG. 2, a handover control method includes the
following steps:
A1. Obtain an identity of the relay node corresponding to a
handover target cell of a UE.
A2. Obtain a identity of control base station corresponding to the
RN according to the identity of the relay node.
In this embodiment, a routing relation between the RN and the
control base station is preset. After the UE obtains the identity
of the relay node, the UE can obtain the corresponding control base
station according to the routing relation.
A3. Send a handover control request to the control base station
according to the identity of control base station, so that the
control base station notifies the RN to perform access control for
the UE.
In this embodiment, according to the relation between the RN and
the identity of control base station, the control base station
(DeNB) of the RN is identified, and therefore, the Handover Request
message can be routed to the correct DeNB and finally sent to the
RN; the RN completes access control for the UE, and the UE can
normally hand over to the cell controlled by the RN.
Embodiment 2
As shown in FIG. 3, a handover control method includes the
following steps:
B1. The base station receives a target cell measurement report sent
by the UE. The target cell measurement report includes a target
cell identity.
In this embodiment, the target cell identity may be an E-UTRAN Cell
Global Identity (E-UTRAN Cell Global Identity, ECGI) or a Physical
Cell Identity (Physical Cell Identity, PCI).
B2. The base station obtains an identity of the relay node
corresponding to the target cell according to the target cell
identity.
The ECGI includes an identity of the relay node (generally, the
initial 20 bits of the ECGI indicate the identity of the base
station or RN corresponding to the cell). If the target cell
identity is an ECGI, the base station can parse the ECGI to obtain
the identity of the relay node from the ECGI.
The PCI does not include the identity of the relay node, and
therefore, if the cell ID of the measurement report is a PCI, the
RN_ID can be obtained in the following way:
The RN reports the PCI of all cells and RN_ID of all cells of the
RN to the DeNB, and then the DeNB transmits the information about a
route to an adjacent eNB. The information about the route may be
transmitted periodically, or triggered by an event (such as joining
of a new RN). The transmitting mode may be: The control base
station sends the information about the route to the adjacent eNB
through an X2 interface between the base station and the base
station; or the DeNB sends an update message that carries the
information about the route through an S1 interface between the
DeNB and the MME, and the MME forwards the information about the
route to the control base station adjacent to the base station
through the S1 interface. According to the update message, the base
station stores information about the routing relation between the
identity of the relay node and the cell identity locally. When
receiving the target cell identity (here the target cell identity
is a PCI) in the measurement report sent by the UE, the base
station obtains the identity of the relay node corresponding to the
PCI according to the information about the routing relation between
the identity of the relay node and the PCI.
B3. The base station searches a stored routing table according to
the identity of the relay node to obtain the identity of control
base station corresponding to the RN.
In this embodiment, when a new RN is added under the control base
station, the base station receives the update message from the
control base station, where the update message carries the
information about the route between the control base station and
the RN under control of the control base station; and the base
station updates the stored routing table according to the
information about the route.
In this embodiment, the information about the route between the
control base station and the RN under control of the control base
station may be generated in the following way:
the RN reports the identity of the relay node of the RN to the
control base station; and
the control base station receives the identity of the relay node,
and generates the information about the route according to the
identity of control base station and the identity of the relay
node.
Step B2 may be combined with step B3 into one step: The base
station searches the stored routing table according to the identity
of the target cell to obtain the identity of control base station
corresponding to the RN of this cell.
B4. The base station sends a handover control request to the
control base station according to the identity of control base
station. In this embodiment, in the case that an X2 communication
interface exists between the base station and the DeNB, the base
station may send the handover control message to the DeNB through
the X2 interface.
B5. The control base station notifies the RN to perform access
control for the UE.
The notification may be sent in many ways. For example, the
handover control request in step B4 may be forwarded to the RN
directly. For the detailed format and content of the handover
control request, see the process of access control executed by the
base station for the UE in the prior art, which is not repeated
herein.
In this embodiment, the base station stores the routing table of
the control base station of the neighboring cell. When the UE hands
over to the RN of the neighboring cell, the base station searches
the routing table to obtain the identity of control base station of
the neighboring cell, and sends a Handover Request message to the
corresponding identity of control base station. In this way, under
control of the identity of control base station, the RN enables the
UE to access the target cell.
The following gives the first application instance of applying the
method provided in the second embodiment of the present invention
to an LTE-Advanced system. This application instance is applicable
to the scenario where an X2 communication interface exists between
base stations. As shown in FIG. 4, the signaling flow includes the
following steps:
C1. The RN is powered on in the coverage of the DeNB, or the RN
moves to a cell of the DeNB.
C2. The RN sends a control message (Control_Message.sub.--1) to the
DeNB. The control message carries the RN_ID of the RN.
C3. The DeNB generates information about the route between the DeNB
and the RN, and sends to the eNB the information about the route
through a message (for example, sending through an
eNB_Configuration_Update message) through an X2 interface.
It is understandable that the information about the route indicates
the communication path from the DeNB to the RN, and includes the
mapping relation between the DeNB_ID and the RN_ID or further
includes the IDs of the intermediate network elements between the
DeNB and the RN in the case of multiple relays.
In step C3 in this application instance, if an X2 interface exists
between the base stations, the DeNB sends the information about the
route to multiple base stations adjacent to the DeNB. In this
embodiment, it is assumed that only one eNB exists.
C4. The eNB updates the routing table according to the information
about the route.
C5. The terminal UE in the connected state moves from a cell of the
eNB to a cell of the RN.
C6. The UE detects the cell identity of the RN (namely, RN_PCI),
and sends the RN_PCI through a measurement report (Measurement
Reports) to the eNB.
C7. The eNB searches the DeNB-RN routing table to determine the
control base station of the RN.
C8. The eNB sends a Handover_Request message to the DeNB through
the X2 interface. The information included in this message is
forwarded by the DeNB and finally sent to the RN.
C9. The RN executes access control.
For the details about how the RN executes access control for the
UE, see the access control procedure of the base station in the
prior art, which is not repeated herein.
When the UE hands over from the eNB to the RN, the UE can interact
with the RN to obtain the identity of the RN cell (RN_PCI), and
report the RN_PCI to the network. According to the RN_PCI, the
network determines the RN to which the UE will hand over, but the
network is unable to determine the control base station (DeNB) that
controls the RN and unable to send the Handover Request message to
the correct DeNB. Consequently, the handover process cannot proceed
normally. To solve such a technical problem, the present invention
provides a handover control method. FIG. 4a is a flowchart of a
handover control method in the second embodiment of the present
invention. This embodiment is applicable to the scenario where no
X2 communication interface exists between the TE-Advanced system
and the base station. For lack of the X2 interface, the information
about the route in this embodiment needs to be configured by an
Operation and Maintenance (O&M) system. This embodiment
includes the following steps:
Ca1. The RN is powered on in the coverage of the DeNB, or the RN
moves to a cell of the DeNB.
Ca2. The RN sends a control message (Control_Message.sub.--1) to
the O&M system. The control message includes the identity of
the RN RN_ID.
Ca3. The O&M (operation and maintenance) system generates
information about the route between the DeNB and the RN, and sends
the information about the route to the eNB through an OAM message,
for example, sending through an eNB_Configuration_Update
message.
The information about the route indicates the communication path
from the DeNB to the RN, and includes the mapping relation between
the DeNB_ID and the RN_ID or further includes the IDs of the
intermediate network elements between the DeNB and the RN in the
case of multiple relays.
In step Ca3 in this application instance, no X2 interface exists
between the base station and the base station, and the O&M
system sends the information about the route to multiple base
stations adjacent to the DeNB. In this embodiment, it is assumed
that only one eNB is adjacent to the DeNB.
Ca4. The eNB updates the routing table according to the information
about the route.
Ca5. The connected UE moves from a cell of the eNB to a cell of the
RN.
Ca6. The UE detects the cell identity of the RN (namely, RN_PCI),
and sends the RN_PCI through a measurement report (Measurement
Reports) to the eNB.
Ca7. The eNB searches the DeNB-RN routing table to determine the
control base station of the RN.
Ca8. The eNB sends a Handover_Required message to an MME through an
S1 interface. The information carried in this message is forwarded
by the MME and the DeNB and finally sent to the RN.
Ca9. The RN executes access control.
For the details about how the RN executes access control for the
UE, see the access control procedure of the base station in the
prior art, which is not repeated herein.
In this embodiment, no X2 interface exists between the base
stations, the O&M system sends to the base station the routing
table of the relay node (RN) of the neighboring cell and the
corresponding control base station (DeNB), and the base station
obtains and stores the routing table. When the UE hands over to the
neighboring cell, the base station searches the routing table to
obtain the identity of control base station of the RN corresponding
to the neighboring cell, and sends a Handover Request message to
the corresponding control base station through the MME. In this
way, under control of the control base station, the RN enables the
UE to access the target cell.
Embodiment 3
As shown in FIG. 5, a handover control method includes the
following steps:
D1. The base station receives a target cell measurement report sent
by the UE. The target cell measurement report includes a target
cell identity.
D2. The base station obtains an identity of the relay node
corresponding to the target cell according to the target cell
identity.
In this embodiment, an identity of the relay node includes a
identity of control base station of the RN and an extension
identity which differentiates between RNs under the same control
base station. It is understandable that after the RN is powered on
in the coverage of the control base station or moves to the
coverage of the control base station, the control base station
allocates an identity of the relay node to the RN.
FIG. 6 shows comparison between the allocated RN_ID and identity of
control base station in this embodiment, supposing that the length
of a identity of control base station is N bits. In this
embodiment, the length of RN_ID is (N+m) bits, where N bits are the
identity of control base station, and the subsequent m bits are the
extension part. The extension bits may be any values that make the
RN different from other RNs under the same DeNB.
D3. The base station obtains the identity of control base station
in the identity of the relay node.
In this embodiment, after the eNB obtains an identity of the relay
node composed of (N+m) bits, the eNB recognizes that the ID is an
identity of an RN rather than an identity of an ordinary base
station according to the length of the ID. Afterward, the eNB
retrieves the initial N bits from the (N+m) bits of the ID to form
the identity of control base station of the RN and obtains the
routing relation between the RN and the DeNB of the RN.
D4. The base station sends a handover control request to the
control base station according to the identity of control base
station, so that the control base station notifies the RN to
perform access control for the UE.
In this embodiment, in the case that an X2 communication interface
exists between the base station and the base station, the base
station may send the handover control message to the DeNB through
the X2 interface.
In the third embodiment, the identity of control base station in
the identity of the relay node is extended so that the
corresponding identity of control base station can be obtained
according to the identity of the relay node in the process of
exercising handover control. In this way, the handover control
signaling is routed to the correct control base station, and the UE
executes access control in the target cell.
Embodiment 4
As shown in FIG. 7, a handover control method includes the
following steps:
E1. The base station receives a target cell measurement report sent
by the UE. The target cell measurement report includes a target
cell identity.
E2. The base station obtains an identity of the relay node
corresponding to the target cell according to the target cell
identity, and sends the identity of the relay node through a
Handover Required message to an MME.
E3. The MME receives the identity of the relay node reported by the
base station.
E4. The MME searches the stored routing table according to the
identity of the relay node to obtain the identity of control base
station corresponding to the RN.
It is understandable that, when a new RN is added under the control
base station, the MME receives an update message from the control
base station, where the update message carries the information
about the route between the control base station and the RN under
control of the control base station; and the MME updates the stored
routing table according to the information about the route.
In this embodiment, the information about the route between the
control base station and the RN under control of the control base
station may be generated in the following way:
the RN reports the identity of the relay node of the RN to the
control base station; and
the control base station receives the identity of the relay node,
and generates the information about the route according to the
identity of control base station and the identity of the relay
node.
E5. The MME sends a handover control request to the control base
station according to the identity of control base station.
E6. The control base station notifies the RN to perform access
control for the UE.
The fourth embodiment differs from the second embodiment in that:
The fourth embodiment is applicable to the scenario where no X2
interface exists between the base station and the control base
station, and therefore, the MME executes handover control, and the
base station and the control base station can communicate through
an S1 interface connected to the MME.
The following gives an application instance of applying the method
provided in the fourth embodiment of the present invention to an
LTE-Advanced system. This application instance is applicable to the
scenario where no X2 communication interface exists between the
base station and the control base station. As shown in FIG. 8, the
signaling flow includes the following steps:
F1. The RN is powered on in the coverage of the DeNB, or the RN
moves to a cell of the DeNB.
F2. The RN sends a control message (Control_Message.sub.--1) to the
DeNB. The control message includes the RN_ID of the RN.
F3. The DeNB generates information about the route between the DeNB
and the RN, and sends to the MME the information about the route
through an S1 message, for example, sending through an
eNB_Configuration_Update message.
F4. The MME updates the stored DeNB-RN routing table according to
the information about the route in the S1 message.
F5. The connected UE moves from a cell of the eNB to a cell of the
RN.
F6. The UE detects the RN_PCI of the RN and sends the RN_PCI to the
eNB through a measurement report.
F7. The eNB sends an S1 message (for example, Handover Required) to
the MME. The message includes the RN_ID of the RN.
F8. The MME searches the DeNB-RN routing table to determine the
control base station (DeNB) of the RN.
F9. The MME sends an S1 handover request Handover_Request to the
control base station (DeNB) of the RN.
F10. The DeNB sends the handover request to the RN.
F11. The RN executes access control for the UE.
Embodiment 5
As shown in FIG. 9, a handover control method includes the
following steps:
G1. The base station receives a target cell measurement report sent
by the UE. The target cell measurement report includes a target
cell identity.
G2. The base station obtains an identity of the relay node
corresponding to the target cell according to the target cell
identity.
In this embodiment, an identity of the relay node includes a
identity of control base station of the RN and an extension
identity which differentiates between RNs under the same control
base station. It is understandable that after the RN is powered on
in the coverage of the control base station B or moves to the
coverage of the control base station, the control base station
allocates an identity of the relay node to the RN.
FIG. 6 shows comparison between the allocated identity of the relay
node and identity of control base station in this embodiment. For
the detailed parameter description, see the third embodiment, which
is not repeated herein.
G3. The base station sends the identity of the relay node to the
MME.
G4. The MME obtains the identity of the relay node, and obtains the
identity of control base station in the identity of the relay
node.
G5. The MME sends a handover control request to the control base
station according to the identity of control base station.
G6. The control base station notifies the RN to perform access
control for the UE.
The fifth embodiment differs from the third embodiment in that: The
fifth embodiment is applicable to the scenario where no X2
interface exists between the base station and the control base
station, and therefore, the MME obtains the identity of control
base station in the identity of the relay node, and sends a
handover control request to the control base station to control the
UE in accessing the RN.
Embodiment 6
As shown in FIG. 10, a handover control method includes the
following steps:
H1. The base station obtains an identity of the relay node
corresponding to a handover target cell of a UE. The identity of
the relay node is the same as the identity of control base station
of the RN.
In this embodiment, before step H1, the DeNB may allocate the
identity of the control base station itself as an identity of the
relay node to the RN when the RN accesses the control base
station.
H2. The base station obtains the identity of control base station
corresponding to the
RN according to the identity of the relay node.
In this embodiment, the identity of the relay node is set to be the
same as the identity of control base station of the RN, and
therefore, the identity of control base station is known once the
base station obtains the identity of the relay node.
H3. The base station sends a handover control request to the
control base station according to the identity of control base
station, where the handover control request carries the identity of
the handover target cell.
In this embodiment, in the case that an X2 interface exists between
the base station and the control base station, the base station can
send the handover request to the control base station through the
X2 interface directly.
H4. The control base station searches for an RN that serves the
target cell according to the identity of the target cell, and
notifies the search RN to control access of the UE.
In this embodiment, the control base station searches for the RN of
the target cell according to the identity of the target cell in any
of the following modes:
Mode 1:
The control base station sends a Handover Request message to all
RNs controlled by the control base station, where the Handover
Request message carries the identity of the target cell.
The RN receives the Handover Request message and judges whether the
target cell identity in the Handover Request message corresponds to
the cell served by the RN, and, if the target cell identity in the
Handover Request message corresponds to the cell served by the RN,
executes access control for the UE.
Mode 2:
The RN reports a list of cells served by the RN to the control base
station beforehand, and the control base station stores the list.
When the control base station searches for the RN that serves the
target cell:
the control base station searches the list of cells served by each
RN controlled by the control base station according to the identity
of the target cell, and obtains the RN that serves the target cell;
and the list of cells is reported by the RN; and
the control base station notifies the search RN to perform access
control for the UE.
Embodiment 7
As shown in FIG. 11, a handover control method includes the
following steps:
S1. The base station obtains an identity of the relay node
corresponding to a handover target cell of a UE. The identity of
the relay node is the same as the identity of control base station
of the RN.
The control base station may allocate the identity of control base
station (DeNB_ID) as an identity of the relay node to the RN when
the RN accesses the control base station.
S2. The base station obtains the identity of control base station
corresponding to the RN according to the identity of the relay
node.
In this embodiment, the identity of the relay node is set to be the
same as the identity of control base station of the RN, and
therefore, the identity of control base station is known once the
base station obtains the identity of the relay node.
S3. The base station sends a handover control request to the MME,
where the handover control request carries the identity of control
base station and the identity of the target cell.
S4. The MME sends a Handover Request message to the control base
station according to the identity of control base station. The
message carries the identity of the target cell.
In this embodiment, in the case that no X2 interface exists between
the base station and the control base station, the handover control
can be executed through the MME due to the existence of the S1
interface between the base station and the MME and the S1 interface
between the control base station and the MME.
S5. The control base station searches for an RN that serves the
target cell according to the identity of the target cell, and
notifies the search RN to control access of the UE.
For the detailed process of searching for the RN that serves the
target cell, see step H4 in the sixth embodiment.
In the sixth embodiment and the seventh embodiment of the present
invention, the identity of control base station serves as the
identity of the relay node. Therefore, the handover control
apparatus can find the corresponding control base station according
to the identity of the relay node directly, and find the RN that
serves the target cell according to the target cell identity, thus
controlling the accessing of the UE to the RN.
Embodiment 8
As shown in FIG. 12, a handover control method includes the
following steps:
T1. The UE receives a broadcast message sent by an RN, where the
broadcast message carries information about a routing relation
between the RN and a control base station of the RN.
In this embodiment, the RN broadcasts the routing relation between
the RN and the control base station through a broadcast message.
The broadcast message may be sent through a preset channel, and the
UE can monitor the preset channel to receive the broadcast message
from the RN.
T2. The UE sends the routing relation information to the base
station to which the UE is currently attached.
T3. According to the information about the route, the base station
notifies the control base station corresponding to the RN to
perform access control for the UE.
The base station may notify the control base station to perform
access control in the following way:
the base station obtains the control base station corresponding to
the RN according to the routing relation information;
in the case that a communication interface exists between the base
station and the control base station, the base station sends a
handover control request to the control base station through the
communication interface;
in the case that no communication interface exists between the base
station and the control base station, the base station sends a
handover control request that carries a routing relation to the
MME; and the MME sends the handover control request to the control
base station; and
after receiving the handover control request, the control base
station notifies the RN to perform access control for the UE.
In the eighth embodiment, the RN broadcasts the routing relation
between the RN and the control base station through a broadcast
message, and the UE ready for accessing the RN reports the received
broadcast message to the base station for the purpose of access
control.
Persons of ordinary skill in the art should understand that all or
part of the steps of the method in the embodiments of the present
invention may be implemented by a program instructing relevant
hardware. The program may be stored in a computer readable storage
medium. The storage medium may be a Read Only Memory (ROM), a
Random Access Memory (RAM), a magnetic disk, or a Compact Disk-Read
Only Memory (CD-ROM).
Embodiment 9
As shown in FIG. 13, a handover control apparatus includes:
an identity of the relay node obtaining unit 1310, configured to
obtain an identity of the relay node corresponding to a handover
target cell of a UE;
a identity of control base station obtaining unit 1320, configured
to obtain a identity of control base station corresponding to an RN
according to the identity of the relay node obtained by the
identity of the relay node obtaining unit 1310; and
a handover control request sending unit 1330, configured to send a
handover control request to a control base station according to the
identity of control base station obtained by the identity of
control base station obtaining unit 1320, so that the control base
station notifies the RN to perform access control for the UE.
In this embodiment, the identity of control base station obtaining
unit 1320 may obtain the identity of control base station in many
modes, as exemplified below:
Mode 1: The identity of control base station obtaining unit is
configured to: receive an update message sent by the control base
station, where the update message carries the information about the
route between the control base station and the RN controlled by the
control base station; update the stored routing table according to
the information about the route; and search the stored routing
table according to the identity of the relay node to obtain the
identity of control base station corresponding to the RN.
Mode 2: The identity of the relay node includes the identity of
control base station of the RN and an extension identity, where the
extension identity is used for differentiating between RNs under
the same control base station, and the identity of control base
station obtaining unit obtains the identity of control base station
in the identity of the relay node.
The handover control apparatus in this embodiment is generally
integrated in the existing base station or MME to execute handover
control for the UE.
When the apparatus in this embodiment is integrated in the existing
base station, the identity of the relay node obtaining unit 1310 is
configured to receive the target cell measurement report that
carries a target cell identity from the UE, and obtain the identity
of the relay node corresponding to the target cell according to the
target cell identity.
When the apparatus in this embodiment is integrated in the existing
MME, the identity of the relay node obtaining unit 1310 is
configured to receive the identity of the relay node reported by
the base station.
Embodiment 10
As shown in FIG. 14, an access control apparatus includes:
a receiving unit 1410, configured to receive a Handover Request
message that carries an identity of a target cell of a UE; and
a handover controlling unit 1420, configured to search for an RN
that serves the target cell according to the identity of the target
cell, and notify the search RN to control access of the UE.
The access control apparatus in this embodiment may be integrated
in the control base station (DeNB) to perform access control for
the UE.
Embodiment 11
As shown in FIG. 15, a network relay apparatus includes:
an information reporting unit 1510, configured to report an
identity of the relay node of the network relay apparatus and a
list of cells served by the network relay apparatus to a
corresponding control base station; and
an access processing unit 1520, configured to receive a
notification from the control base station and perform access
control for a UE.
The network relay apparatus in this embodiment reports the identity
of the relay node of the network relay apparatus and a list of
cells served by the network relay apparatus to the control base
station so that the control base station can route the access
control message to the RN correctly and perform access control for
the UE.
Embodiment 12
As shown in FIG. 16, a network relay apparatus includes:
a identity of control base station obtaining unit 1610, configured
to obtain a identity of control base station of the network relay
apparatus;
a information about the route generating unit 1620, configured to
generate information about the route according to the identity of
control base station and an identity of the relay node of the
network relay apparatus; and
a broadcasting unit 1630, configured to broadcast the information
about the route generated by the information about the route
generating unit throughout cell coverage of the network relay
apparatus.
The network relay apparatus in this embodiment sends broadcast
messages so that the UE ready for accessing the network relay
apparatus can obtain the information about the route between the
network relay apparatus and the control base station in time and
implement handover.
Embodiment 13
As shown in FIG. 17, a UE includes:
a broadcast message receiving unit 1710, configured to receive a
broadcast message sent by an RN, where the broadcast message
carries information about a routing relation between the RN and a
control base station of the RN; and
a information about the route sending unit 1720, configured to send
the routing relation information to an base station to which the UE
is currently attached, so that the base station notifies the
control base station of the RN to perform access control for the UE
according to the routing relation information.
The UE in this embodiment reports the information about the route
between the control base station and the RN corresponding to the
handover target cell to the current base station, and therefore,
the current base station can route the Handover Request message to
the correct control base station, and the UE can hand over between
cells.
Embodiment 14
As shown in FIG. 18, a communication system includes a handover
control apparatus 1810, an access control apparatus 1820, an RN
1830, and a UE 1840, where:
the UE 1840 is configured to send an identity of the relay node
corresponding to a handover target cell to the handover control
apparatus, and access the target cell under control of the RN;
the handover control apparatus 1810 is configured to: obtain the
identity of the relay node corresponding to the handover target
cell of a UE, obtain a identity of control base station
corresponding to the RN according to the identity of the relay
node, and send a handover control request to the access control
apparatus 1820 according to the identity of control base
station;
the access control apparatus 1820 is configured to receive the
handover control request from the handover control apparatus 1810,
and notify the RN 1830 to perform access control for the UE;
and
the RN 1830 is configured to receive the notification from the
access control apparatus 1820, and perform access control for the
UE 1840.
The communication system provided in the fourteenth embodiment
identifies the control base station of the RN according to the
relation between the RN and the control base station, and
therefore, the Handover Request message can be routed to the
correct control base station and finally sent to the RN, and the UE
can normally hand over to the cell controlled by the RN.
Expounded above are a handover control method, apparatuses, and a
communication system under the present invention. Some exemplary
embodiments are provided for describing the principle and
implementation of the invention; however, the embodiments are only
intended to help understand the method and core idea of the
invention. It is apparent that those skilled in the art can make
modifications and variations to the invention without departing
from the spirit and scope of the invention. Therefore, the
specification shall not be construed as a limitation to the
invention.
After reading the foregoing embodiments, those skilled in the art
are clearly aware that the embodiments of the present invention may
be implemented through hardware, or, preferably in most
circumstances, through software in addition to a necessary
universal hardware platform. Therefore, the technical solution
under the present invention or its novelty in contrast to the prior
art may be embodied as a software product. The software product may
be stored in a computer readable storage medium and incorporates
several instructions for instructing a computer device (for
example, a personal computer, a server, or a network device) to
execute the method specified in any embodiment of the present
invention.
Although the invention is described through some exemplary
embodiments, the invention is not limited to such embodiments. It
is apparent that those skilled in the art can make modifications
and variations to the invention without departing from the spirit
and scope of the invention. The invention is intended to cover the
modifications and variations provided that they fall within the
scope of protection defined by the following claims or their
equivalents.
* * * * *