DESCRIPTION
RADIO BASE STATION, SERVER, MOBILE COMMUNICATION SYSTEM,
AND OPERATION CONTROL METHOD
Technical Field
[OOOl]
The present invention relates to a radio base station, a server, a mobile
communication system, and an operation control method and, in particular, to
10 control of a logical interface defined between radio base stations.
Background Art
[0002]
Fig. 32 is a sequence diagram of an X2 message exchanged between
15 eNBs (Evolved Node Bs, radio base station apparatuses) in establishing a
logical interface (an X2 interface) defined between the eNBs in a mobile
communication network, specifically, a network of LTE (Long Term
Evolution). Establishment of an X2 link (X2 interface) between an eNB (#I)
201 and an eNB (#2) 202 is performed as follows: either one transmits an X2
20 SETUP REQUEST message (step S112) and receives an X2 SETUP
RESPONSE message from the other (step S113) (refer to Non Patent
Literature 1).
[0003]
The X2 link i s s e t between the eNBs 201 and 202, whereby in UE (User
25 Equipment, a mobile terminal) performing handover between the eNBs 201
and 202, the eNBs 201 and 202 exchange information using the X2 link, and
thereby the handover can be achieved. If the X2 link does not exist,
information exchange via an S1 interface is needed, and a time required for
handover increases. In addition, burden of a core network also increases.
30 [0004]
The logical X2 interface of an application layer is defined on an SCTP
(Stream Control Transmission Protocol) (refer to Non Patent Literature 2),
which is a transport layer (Non Patent Literatures 3 and 4). One SCTP
association that is established in step S 11 1 is used for one X2 link between the
cNBs 201 and 202.
[OOOS]
As one of SON (Self Organizing Network) functions that are discussed
in 3GPP (3 rd Generation Partnership Project), there exists a function of an
5 ANR (Automatic Neighbor-Relation). It is one of the ANR functions that
detects an eNB existing in a neighborhood, and that sets an X2 link with the
neighboring eNB (refer to No11 Patent Literature 5).
Citation List
10 Non Patent Literature
[0006]
Non patent literature 1: 3GPP TS 36.423
Non patent literature 2: RFC 4960
Non patent literature 3: 3GPP TS 36.422
15 Non patent literature 4: 3GPP TS 36.420
Non patent literature 5: 3GPP TS 36.300
Non patent literature 6: 3GPP TS 36.33 1
Summary of Invenlion
20 Technical Problem
[0007]
By the above-mentioned ANR function, in a neighboring eNB being
newly detected, it is expected to establish an X2 link with the eNB.
However, there is a limit to the number of X2 links that can be set by one eNB,
25 i.e., the number of SCTPs, in a real network, and it is impossible to set the X2
link with all the eNBs detected by the ANR function without limitation.
[OOOS]
In addition, depending on a type of eNB, few users can be
accommodated or a cell radius is small. There may be l i t t l e advantage of
30 establishing the X2 link with such eNB.
[0009]
In setting the X2 link with the neighboring cNB detected by the ANR
function, needed is a mechanism to control (select) establishment and
disconnection of the X2 link using a certain logic.
[OO lo]
An object of the present invention is to solve the above-mentioned
problem, and to provide a radio base station, a server, a mobile
communication system, and an operation control method that can suppress
5 establishment .of a useless logical interface.
Solutiod to Problem
[OOll]
A first exemplary aspect of the present invention is a radio base station
10 of a mobile communication system including a determination means for
determining whether it is proper or not to establish a logical interface with a
neighboring radio base station by using a attribution information of the
neighboring radio base station.
[0012]
15 A second exemplary aspect of the present invention is an operation
control method for a radio base station of a mobile communication system
including a step of determining whether it is proper or not to establish a
logical interface with a neighboring radio base station by using a attribution
information of the neighboring radio base station.
20 [0013]
A third exemplary aspect of the present invention is a server that is
connected to radio base stations of a mobile communication system including
a determination means for determining whether it is proper or not to establish
a logical interface with a neighboring radio base station by using a attribution
25 information of the neighboring radio base station.
[0014]
A fourth exemplary aspect of the present invention is an operation
control method for a server that is connected to radio base stations of a mobile
communication system including a step of determining whether it is proper or
30 not to establish a logical interface with a neighboring radio base station by
using a attribution information of the neighboring radio base station.
[OOlS]
A fifth exemplary aspect of the present invention is
a mobile communication system including radio base stations and
determination means for determining whether it is proper or not to establish a
logical interface between the radio base stations by using a attribution
information of the radio base stations.
[0016]
5 A sixth exemplary aspect of the present invention is an-operation
control method for a mobile communication system including a step of
determining whether it is proper or not to establish a logical interface with the
radio base stations by using a attribution information of the radio base
stations.
10
Advantageous Effects of Invention
[00 171
According to the present invention, obtained is an advantageous effect
capable of suppressing establishment of a useless logical interface.
15
Brief Description of the Drawings
[00 181
Fig. 1 is a sequence diagram showing operation of eNBs in a mobile
communication system according to a first embodiment of the present
20 invention;
Fig. 2 is a diagram showing a configuration of the eNB of Fig. 1;
Fig. 3 is a database held by the eNB of Fig. 1;
Fig. 4 is a database held by the eNB of Fig. 1. The Pico eNB is set to
the database as a value of an eNB type of the self-eNB;
25 Fig. 5 is a table showing information elements added to an X2 SETUP
REQUEST message;
Fig. 6 is a table showing information elements added to an X2 SETUP
RESPONSE message;
Fig. 7 is a database held by the eNBs in the second embodiment of the
30 present invention;
Fig. 8 is a database held by the eNBs in the second embodiment of the
present invention;
Fig. 9 is a flow chart showing operation of the eNB in the second
embodiment of the present invention;
Fig. 10 is a sequence diagram showing operation of the eNBs in the
third embodiment of the present invention;
Fig. 11 is a table showing information elements added to an X2 SETUP
REQUEST message in the third embodiment of the present invention;
5 Fig. 12 is a table showing information elements added to an XZ SETUP
RESPONSE message in the third embodiment of the present invention;
Fig. 13 is a table showing information elements added to an ENB
CONFIGURATION UPDATE message in the third embodiment of the present
invention;
10 Fig. 14 is a database held by the eNB in the third embodiment of the
present invention;
Fig. 15 is a flow chart showing operation of the eNB after
establishment bf an X2 link in the third embodiment of the present invention;
Fig. 16 is a database held by the eNB in'the third embodiment of the
15 present invention;
Fig. 17 is a flow chart showing operation of the eNB in information of
the number of users being received in the third embodiment of the present -
invention;
Fig. 18 is a flow chart showing operation of the eNB in a neighboring
20 eNB being newly detected in the third embodiment of the present invention;
Fig. 19 is a sequence diagram showing operation of the eNBs in the
fourth embodiment of the present invention;
Fig. 20 is a database held by the eNB in the fourth embodiment of the
present invention;
25 Fig. 21 is a database held by the eNB in the fourth embodiment of the
present invention;
Fig. 22 is a table showing elements added to Cause included in an X2
SETUP FAILURE message in the fourth embodiment of the present invention;
Fig. 23 is a diagram showing a configuration of a mobile
30 communication system according to the fifth embodiment of the present
invention;
Fig. 24 is a diagram showing a configuration of the management server
150 of Fig. 23;
Fig. 25 is a database held by the management server in the fifth
embodiment of the present invention;
Fig. 26 is a sequence diagram showing operation of the mobile
communication system according to the fifth embodiment of the present
invention;
5 Fig. 27 is a sequence, diagram showing operation of a mobile
communication system according to the sixth embodiment of the present
invention;
Fig. 28 is a database held by the management server in the sixth
embodiment of the present invention;
10 Fig. 29 is a database held by the management server in the sixth
embodiment of the present invention;
Fig. 30 is a sequence diagram showing operation of a mobile
communication system according to the seventh embodiment of the present
invention;
15 Fig. 31 is a database held by the management server in the seventh
embodiment of the present invention; and
Fig. 32 is a sequence diagram of an X2 message exchanged between
eNBs.
20 Description of Embodiments
[0019]
Hereinafter, embodiments of the present invention will be explained
with reference to drawings. First, a summary of a mobile communication
system according to the present invention will be explained. The mobile
25 communication system according to the present invention includes radio base
stations, and further includes determination means for determining propriety
of establishment of a logical interface between radio base stations based on
attribution information of the radio base stations. Since the determination
means determines the propriety of establishment of the logical interface
30 between the radio base stations based on the attribution information of the
radio base stations, establishment of a useless logical interface (a logical
interface with low need for maintenance) can be suppressed.
[0020]
Fig. 1 is a sequence diagram showing operation of eNBs in a mobile
communication system according to a first embodiment of the present
invention. An eNB (#I) 101 and an eNB (#2) 102 are radio base station
apparatuses of LTE.
[0021]
5 Fig. 2 is a diagram showing a configuration of the eNB 101 of Fig. 1,
and the eNB 102 also has an equivalent configuration. A determination unit
13 determines propriety of establishment of an X2 link w i t h a neighboring
eNB based on an eNB type of the neighboring eNB. A control unit 11
transmits and receives a message totfrom the neighboring eNB using a
10 communication unit 12. In addition, the control unit 11 performs control for
disconnecting the X2 link in accordance with a determination result of the
determination unit 13. A storage unit 14 includes various databases, which
will be mentioned later. A radio communication unit 15 performs
communication with UE, which is not shown.
15 [0022]
Fig. 3 is a database held by the eNB 101 of Fig. 1. A value called a
Macro eNB is set to the database as a value of an eNB type of the self-eNB.
That is, the eNB 101 having the database i s the Macro eNB. As values that
eNB types can take, the Macro eNB, a Micro eNB, a Pico eNB, and an HeNB
20 (Home eNB) are assumed.
[0023]
In addition, the Pico eNB and the HeNB are set to the database as
values of eNB types in which establishment of the X2 link should be
restricted. As the values that can be taken here, in addition to four types of
25 the Macro eNB, the Micro eNB, the Pico eNB, and the HeNB, values obtained
by freely combining each of them can be employed (the Macro eNB+the Pico
eNB, the Macro eNB+the Pico eNB+the HeNB, etc.).
[0024]
Fig. 4 is a database held by the eNB 102 of Fig. 1. The Pico eNB is
30 set to the database as a value of an eNB type of the self-eNB. That is, the
eNB 101 has the Macro eNB, whereas the eNB 102 has the Pico eNB. In
addition, the Macro eNB is set as a value of an eNB type in which
establishment of the X2 link should be restricted in the eNB 102.
[0025]
Fig. 5 is a table showing information clcments added to an X2 SETUP
REQUEST message. An IE (Information Element) called an eNB type 301 is
newly defined in an X2 SETUP REQUEST message described in 9.1.2.3 of
Non Patent Literature 1. The Macro eNB, the Micro eNB, the Pico eNB, and
5 the HeNB can be set as a range of the IE that indicates the eNB type,
[0026]
Fig. 6 is a table showing information elements added to an X2 SE'TYJP
RESPONSE message. An IE called an eNB type 302 is newly defined in an
X2 SETUP RESPONSE message described in 9.1.2.4 of Non Patent Literature
10 1. The Macro eNB, the Micro eNB, the Pico eNB, and the HeNB can be set
as a range of the IE that indicates the eNB type.
[0027]
Hereinafter, with reference to Fig. 1, will be explained operation in the
eNB 10 1 detecting the eNB 102 by means of an ANR function and trying to
15 establish an X2 link.
[002S]
Establishment of an SCTP link is performed between the eNBs 101 and
102 (step S l ) . Since an SCTP procedure used in this case is well known by
Non Patent Literature 2, etc., details thereof are omitted. When the SCTP
20 link is established, the eNB 101 transmits an X2 SETUP REQUEST message to
the eNB 102 (step S2). In this case, the message including an eNB type of
the self-eNB 101 is transmitted as shown in Fig. 5. This eNB type coincides
with the eNB type of the self-eNB shown in Fig. 3.
[0029]
25 When receiving the X2 SETUP REQUEST message, the eNB 102
transmits an X2 SETUP RESPONSE message (step S3). In this case, the
message including an eNB type of the self-eNB 102 is transmitted as shown in
Fig. 6. This eNB type coincides with the eNB type of the self-eNB shown in
Fig. 4.
30 [0030]
The eNB 101 determines propriety of establishment of the X2 link with
the eNB 102 based on the eNB type of the opposing eNB 102 included in the
X2 SETUP RESPONSE message (step S4). The eNB 101 confirms whether or
not the eNB type of the eNB 102 is included in the eNB types of Fig. 3 in
9
which establishment of the X2 link should be restricted. Since the eNl3 typc
of the eNB 102 is included in the example, disconnection of the SCTP link is
started.
[003 11
5 Although SCTP link disconnection-operation is described in Non Patent
Literature 2, it will be explained hereinafter. The eNB 101 transmits an
SCTP SHUTDOWN message in order to disconnect the SCTP link (step SS).
When receiving the SCTP SHUTDOWN message, the eNB 102 returns an
SCTP SHUTDOWN ACK message (step S6). The eNB 101 transmits an SCTP
10 SHUTDOWN COMPLETE message, and disconnection of the SCTP link is
completed (step S7). Instead of the above disconnection procedure, the eNB
101 transmits an SCTP ABORT message to the eNB 102, and also thereby
disconnection can be made.
[0032]
15 In step S4, when the eNB type of the eNB 102 is not included in the
eNB types in which establishment of the X2 link should be restricted, the eNB
101 does not perform disconnection of the SCTP link in order to maintain the
X2 link.
[0033]
2 0 Although in the above explanation, the eNB 101 determines the
propriety of establishment of the X2 link after the X2 link is established (the
X2 SETUP REQUESTIRESPONSE are exchanged), the eNB 102 may
determine the propriety of establishment of the X2 link with the eNB 101 in
response to reception of the X2 SETUP REQUEST message. In this case, the
25 eNB 102 confirms whether or not the eNB type of the eNB 101 included in the
X2 SETUP REQUEST message is included in the eNB type of Fig. 4 in which
establishment of the X2 link should be restricted, and thereby determines the
propriety of establishment of the X2 link. Then, if included, the eNB 102
does not establish the X2 link by returning to the eNB 101 an X2 SETUP
30 FAILURE message instead of the X2 SETUP RESPONSE message.
[0034]
In addition, although in the above explanation, propriety determination
of establishment of the X2 link is performed based on the eNB type of the
eNB, determination criterion is not limited to the eNB type, and various
attribution information of the eNB can be used. For example, may be used: a
cell radius of the eNB (for example, values, such as a Very Largc, a Largc, a
Medium, and a Small, are taken); the number of users that can be
accommodated by the eNB; the number of uscrs of the eNB (the number of
5 users having been in a service area of a cell of the eNB (the number of UE of
an IDLE MODE and a CONNECTED MODE, refer to Non Patent Literature 6
for details of the each mode)); a load condition of the eNB (for example,
values, such as a High load, a medium load, and a low load, are taken); and a
cell radius of the eNB (unlike the above-mentioned cell radius, it is
10 represented by means of a Reference signal power (dBm) of the eNB). When
the number of users that can be accommodated by the eNB, the number of
users, and the Reference signal power (dBm) are used, the propriety
determination of establishment of the X2 link is performed by comparing
values of the above attribution information with predetermined threshold
15 values (if the values are smaller than the threshold valucs, the X2 link is
disconnected).
[0035]
As explained above, in the first embodiment of the present invention,
the eNBs 101 and 102 mutually exchange their own eNB types in the
20 establishment of the X2 link, and additionally, the each eNB determines the
propriety of establishment of the X2 link based on the eNB type of the
opposing eNB. Accordingly, since each eNB can select whether to establish
the X2 link according to the cNB type of the opposing eNB, it becomes
possible to save resources for the X2 IinklSCTP link.
25 [0036]
Next, a second embodiment of the present invention will be explained.
Although in the first embodiment of the present invention, the propriety of
establishment of the X2 link is determined in every establishment of the X2
link, in the second embodiment of the present invention, determination is not
30 performed in every establishment of the X2 link, but the propriety of
establishment of the established X2 link is determined when the number of
established X2 links reach a predetermined value. It is to be noted that a
basic configuration of the second embodiment of the present invention is the
same as that of the first embodiment of the present invention, and that the
eNBs 101 and 102 hold the databases of Figs. 3 and 4, respectively also in the
second embodiment of the present invention. In addition, in establishing the
X2 link between the eNBs 101 and 102, the eNBs 101 and 102 mutually
exchange the eNB types of the self-eNBs as in steps S2 and S3 of Fig. 1.
5 [0037]
Figs. 7 and 8 are databases held by the eNBs in the second embodiment
of the present invention. In the database of Fig. 7, the number 100 is set as
the maximum number of X2 links (an upper limit of the number of established
X2 IinksISCTP links) of the self-eNB. In the database of Fig. 8, stored are
10 identifiers (eNB IDS) and eNB type information of opposing eNBs in which
X2 links have been established with the self-eNB. Notification of the eNB
IDS and the eNB type information of the opposing eNBs is, as mentioned
above, performed from the opposing eNBs in the establishment of the X2
links. Whenever establishing and disconnecting the X2 link, the eNB
15 updates the database of Fig. 8.
[0038]
Fig. 9 is a flow chart showing operation of the eNB in the second
embodiment of the present invention. Hereinafter, with reference to Fig. 9,
will be explained operation in the eNB 101 detecting the eNB 102 by means of
20 the ANR function.
[0039]
The eNB 101 confirms whether or not the number of established X2
links of the eNB 101 is the same as the maximum number of X2 links of Fig. 7
(step S11).
25 If it reaches the maximum number of X2 links, the eNB 101 determines
propriety of establishment of the established X2 links based on the eNB types
of the database of Fig. 8, and confirms presencelabsence of the disconnectable
X2 links (step S12). Namely, in the database of Fig. 8, searched are the eNB
types included in the eNB types of Fig. 3 (in this case, the Pico eNB, the
30 HeNB) in which establishment of the X2 link should be restricted. In Fig. 8,
the established X2 links with an eNB ID#], an eNB ID#2, and an eNB ID#5
are selection objects as the disconnectable X2 links.
[0040]
The eNB 101 then disconnects the disconnectable X2 links (step S13).
Namely, a sequence of steps S5 to S7 of Fig. 1 is carried out. When the
plurality of X2 links exist as the selection objects, the eNB 101 may
disconnect ihe arbitrary X2 link(s), or may disconnect all of them. When ihe
number of established X2 links does not reach the maximum number of X2
5 links after step S13 or in step S11, the eNB 101 establishesan X2 link with
the detected eNB 102 (step S 14).
[0041]
Although in the above explanation, propriety determination of
establishment of the X2 links in step S12 is performed based on the eNB types
10 of the eNBs, similarly to the first embodiment of the present invention,
determination criterion is not limited to the cNB types, and various attribution
information of the eNBs can he used. When the number of users that can be
accommodated by the eNB, the number of users, and the Reference signal
power (dBm) are used, the eNB 101 may perform propriety determination by
15 comparing values of the above attribution information with predetermined
threshold values, or may disconnect the established X2 link with the eNB
having a lowest value.
100421
As explained above, since in the second embodiment of the present
20 invention, establishing the X2 links also with the eNBs of the eNB types in
which establishment of the X2 link should be restricted until the number of
established X2 links reaches the upper limit, and determining the propriety of
establishment of the established X2 links when the number of established X2
links reaches the upper limit, the eNB 101 can disconnect the useless X2 links
25 to establish an X2 link with a newly detected neighboring eNB, even when the
number of established X2 links reaches the upper limit.
[0043]
Next, a third embodiment of the present invention will be explained.
Although in the first and second embodiments of the present invention,
30 notification of attribution information of the opposing eNB is performed only
in the X2 link being established between the eNBs 101 and 102, in the third
embodiment of the present invention, each eNB regularly notifies of
attribution information of the self-eNB an eNB in which an X2 link has been
established with the self-eNB in consideration of a case where the attribution
information, notification of which is performed, dynamically changes. It is
to be noted that although a basic configuration of the third embodiment o l thc
present invention is the same as that of the first embodiment of the present
invention, in the following explanation, the number of users of the eNB (the
5 number of users having been in the service area of the cell of the eNB) is used
instead of the eNB type, and thus the eNBs 101 and 102 need not hold the
databases of Figs. 3 and 4, respectively. In addition, each of the eNBs 101
and 102 holds the database of Fig. 7.
[0044]
10 Fig. 10 is a sequence diagram showing operation of the eNBs in the
third embodiment of the present invention. Notification of the number of
users is performed using an X2 message. In an ALT 1, shown is operation of
exchanging information of the number of users between the eNBs 101 and 102
at the time of establishment of the X2 link. In an ALT 2, shown is operation
15 of notifying the opposing eNB of the information of the number of users of the
self-eNB on an established X2 link using an ENB CONFIGURATION UPDATE
message. In an ALT 3, operation of disconnecting the X2 IinkISCTP link is
shown. An opportunity of the each ALT will be mentioned later.
[0045]
20 Fig. 11 is a table showing information elements added to an X2 SETUP
REQUEST message in the third embodiment of the present invention. Unlike
Fig. 5, an IE called a Number of users (the number of users) 3 11 is specified
in Fig. 11. Fig. 12 is a table showing information elements added to an X2
SETUP RESPONSE message in the third embodiment of the present invention.
25 Unlike Fig. 6, an IE called a Number of users 312 is specified in Fig. 12.
The eNBs 101 and 102 can know the mutual number of users by exchanging
the messages of Figs. 11 and 12 at the time of establishment of the X2 link.
[0046]
Fig. 13 is a table showing information elements added to an ENB
30 CONFIGURATION UPDATE message in the third embodiment of the present
invention. An IE called a Number of users 313 is newly specified in the ENB
CONFIGURATION UPDATE message described in 9.1.2.8 of Non Patent
Literature 1. The eNBs 101 and 102 transmit this message on the X2 link,
and thereby can inform the opposing eNB of the information of the number of
users o f the self-eNB.
[0047]
It is to be noted that although the Number of users (the number of
users) specified in Figs. 11 to 13 is, as mentioned above, the number of users
5 having been in the service area of the cell of the self-eNB (the number o f UE
o f the IDLE MODE and the CONNECTED MODE, refer to Non Patent
Literature 6 for details o f the each mode), may be employed a method for
notifying o f the number of users o f the IDLE MODE and the CONNECTED
MODE by means of different parameters, respectively. In addition, since it
10 is also considered that one eNB has a plurality of cells, in that case, the
number o f users for each cell may be specified.
[0048]
Fig. 14 is a database held by the eNB in the third embodiment o f the
present invention. In the database o f Fig. 14, stored are identifiers (eNB
16 I D S ) and information o f the number o f users o f opposing eNBs in which X2
links have been established with the self-eNB. Newest information o f the
number of users received for eacheNB is recorded. The number o f users, 10
i s shown in an eNB ID#2, and it is the smallest number o f users.
[0049]
2 0 Fig. 15 is a flow chart showing operation of the eNB after
establishment of an X2 link in the third embodiment o f the present invention.
When establishing the X2 link with the opposing eNB, the eNB starts
timekeeping by means o f a timer, which is not shown (step S31), and when a
predetermined time elapses (step S32), the eNB notifies o f the opposing eNB
25 an ENB CONFIGURATION UPDATE message including the number of users
(step S33). The above operation is repeated during establishment of the X2
link with the opposing eNB, and thereby the ENB CONFIGURATION UPDATE
message is regularly transmitted to the opposing eNB. From this, a database
can be updated in the opposing eNB. It is to be noted that step S33 o f Fig. 15
30 corresponds to step S26 of Fig. 10.
[0050]
Fig. 16 is a database held by the eNB in the third embodiment o f the
present invention. In the database, a timer value o f the timer explained in
F i g . 15 is specified. In this case, the timer value is set as 60 seconds. That
is, notification of the information o f the number of users of the self-eNB is
performed to the opposing eNB after elapse o f 60 seconds.
roo5 I ]
Fig. 17 is a flow chart showing operation of the eNB in information o f
5 the number of users being received in the third embodiment o f the present.
invention. When receiving an X2 SETUP REQUEST message, an X2 SETUP
RESPONSE message, and an ENB CONFIGURATION UPDATE message from
an opposing eNB, the eNB updates the database o f Fig. 14 held by the
self-eNB (step S41). It is to be noted that step S41 of Fig. 17 corresponds to
10 steps S23, S25, and S27 of F i g . 10. After steps S23 and S27 o f Fig. 10, the
eNB 102 transmits to the eNB 101 the X2 SETUP RESPONSE message of step
S24 and an ENB CONFIGURATION UPDATE ACK message of step S28,
respectively.
[0052]
15 Fig. 18 is a flow chart showing operation o f the eNB in a neighboring
eNB being newly detected in the third embodiment of the present invention.
When detecting the eNB 102 by means o f the ANR function, the eNB 101
confirms whether or not the number o f established X2 links of the eNB 101
reaches a number obtained by subtracting 1 from the maximum number o f X2
20 links of Fig. 7 (step S 5 1 ) . I f the number o f established X2 links of the eNB
101 reaches the number obtained by subtracting 1 from the maximum number
of X2 links, the eNB 101 establishes an X2 link with the detected eNB 102
(step S52). It is to be noted that step S52 of Fig. 18 corresponds to steps S21
to S25 o f Fig. 10.
25 [0053]
Next, the eNB 101 determines propriety of establishment o f the
established X2 links based on the information of the number o f users o f the
database o f F i g . 14, and selects the X2 link that should be disconnected (step
S53). Here, selected is the neighboring eNB having the lowest number of
50 users in the database of F i g . 14. The eNB 101 then disconnects the
established X2 link with the selected eNB (step S54). It is to be noted that
step S54 o f Fig. 18 corresponds to the SCTP link disconnection operation of
step S29 o f Fig. 10. When the number of established X2 links does not reach
the number obtained by subtracting 1 from the maximum number o f X2 links
in step S51, the cNB 101 cstablislies the X2 link with the detected eNB 102
similarly to step S52 (step S55).
lo0541
Although in the above explanation, propriety determination of
5 establishment of the X2 links in step S53 is performed based on the number of
users of the eNB, determination criterion is not limited to the number of
users, and various attribution information of the eNB can be used. For
example, may be used the cell radius of the eNB (for example, values, such as
the Very Large, the Large, the Medium, and the Small, are taken); the number
10 of users that can be accommodated by the eNB; the load condition of the eNB
(for example, values, such as the High load, the medium load, and the low
load, are taken); and the cell radius of the eNB (unlike the above-mentioned
cell radius, it is represented by means of the Reference signal power (dBm) of
the eNB).
15 [0055]
As explained above, in the third embodiment of the present invention,
the eNB 101 establishes the X2 link with the neighboring eNB until the
number of established X2 links reaches the number obtained by subtracting 1
from the maximum number of X2 links, and when the number of established
20 X2 links reaches the number obtained by subtracting 1 from the maximum
number of X2 links, the eNB 101 determines the propriety of establishment of
the established X2 links, and can disconnect the useless X2 link. In
addition, since each eNB regularly notifies of the attribution information of
the self-eNB the eNB in which the X2 link has been established with the
25 self-eNB, the third embodiment of the present invention is more suitable than
a case of using dynamically changing information, such as the number of
users, for the propriety determination of establishment of the X2 link.
[0056]
Next, a fourth embodiment of the present invention will be explained.
30 Although in the first to third embodiments of the present invention, propriety
of establishment of the X2 link is determined based on thc attribution
information of the eNB acquired via the X2 link, in the fourth embodiment of
the present invention, each eNB holds a database in which attribution
information of each of the eNBs in the mobile communication system is
previously stored, and determines propriety of establishment of an X2 link
using the databasc. It is to be noted that although a basic configuration of
the fourth embodiment of the present invention is the same as that of the first
embodiment of the present invention, the above-described databases are used
5 in the following explanation, and thus the eNBs 101 and 102 need not hold the
databases of Figs. 3 and 4, respectively.
[0057]
Fig. 19 is a sequence diagram showing operation of the eNBs in the
fourth embodiment o i the present invention. Figs. 20 and 21 are databases
10 held by the eNB in the fourth embodiment of the present invention. In the
database of Fig. 20, previously stored are an identifier (eNB ID) of each of
eNBs in the mobile communication system and an eNB type thereof. In the
database of Fig. 21, registered are the eNB types in which establishment of
the X2 link should be restricted.
15 [0058]
Fig. 22 is a table showing elements added to Cause included in an X2
SETUP FAILURE message in the fourth embodiment of the present invention.
In Cause described in 9.2.6 of Non Patent Literature 1, a cause called a
"prohibited eNB Type" is added in >>Transport Layer Cause.
20 [0059]
Hereinafter, with reference to Fig. 19, will be explained operation in
the eNB 101 detecting the eNB 102 by means of the ANR function and trying
to establish an X2 link.
[0060]
2 5 Establishment of an SCTP link is performed between the eNBs 101 and
102 (step S61). The eNB 101 transmits an X2 SETUP REQUEST message to
the eNB 102 (step S62). This message does not include eNB type
information.
[0061]
30 When receiving the X2 SETUP REQUEST message, the eNB 102
determines propriety of establishment of the X2 link with the eNB 101 using
the holding databasc (step S63). Namely, the eNB 102 acquires an eNB type
of the eNB 101 from the database of Fig. 20 held by the eNB 102 based on an
eNB ID of the source eNB 101 included in the X2 SETUP REQUEST message.
18
In addition, the eNB 102 refers to the database of Fig. 21 that the eNB 102
has, and confirms whether or not the eNB type of the eNB 101 is included in
the eNB types in which establishment of the X2 link should be restricted.
[0062]
5 If in step S63, the eNB type of the eNB 101 falls under the eNB types
in which establishment of the X2 link should be restricted, the eNB 102
transmits the X2 SETUP FAILURE message to the eNB 101 in order to reject
the establishment of the X2 link (step S64). In this case, it is necessary to
include Cause in the X2 SETUP FAILURE message, and Cause shown in Fig.
10 22 is proposed as new Cause. It is to be noted that if in step S63, the eNB
type of the eNB 101 does not fall under the eNB types in which establishment
of the X2 link should be restricted, the eNB 102 transmits an X2 SETUP
RESPONSE message to the eNB 101, and establishes the X2 link.
[0063]
15 After step S64, the eNB 102 can start disconnection of the SCTP link to
release a resource of a transport layer between the eNB 101 and the eNB 102
itself (step S65). The eNB 101 may start disconnection of the SCTP link.
[0064]
The databases of Figs. 20 and 21 are updated when an operator changes
20 a policy (for example, an eNB type that has not been registered until now is
added to the database of Fig. 21), when a value is input to the each database
for the first time, etc. Taking the opportunity of such update of the
databases of Figs. 20 and 21, when there exists an established X2 link with an
eNB of the eNB type in which establishment of the X2 link should be
25 restricted, disconnection of the SCTP link may be started in order to
disconnect the X2 link (step S66).
[0065]
Although in the above explanation, the eNB 102 that has received the
X2 SETUP REQUEST message determines the propriety of establishment of
30 the X2 link in step S63, in the eNB 101 detecting the eNB 102 by means of the
ANR function and trying to establish the X2 link, the eNB 101 may determine
the propriety of establishment of the X2 link with the detected eNB 102 using
the databases of Figs. 20 and 21 held by the self-eNB 101. Here, if an eNB
type of the eNB 102 falls under the eNB types in which establishment of the
X2 link should be restricted, the eNB 101 does not transmit the X2 SETUI'
REQUEST message to the eNB 102 or does not establish an SC'1'P link with thc
eNB 102, or when the SCTP link has been already established with thc eNB
102, the eNB 101 can start disconnection of the SCTP link.
5 - LO0661
In addition, although in the above explanation, propriety determination
of establishment of the X2 link is performed based on the eNB type of the
eNB, similarly to the other embodiments of the present invention,
determination criterion is not limited to the eNB type, and various attribution
10 information of the eNB can be used.
[0067]
As explained above, in the fourth embodiment of the present invention,
each eNB holds the database in which the eNB type of each of the eNBs in the
mobile communication system is previously stored, and determines the
15 propriety of establishment of the X2 link based on the eNB type of the
opposing eNB acquired from the database. Accordingly, since each eNR can
select whether to establish the X2 link according to the eNB type of the
opposing eNB, it becomes possible to save resources for the X2 link/SCTP
link.
20 [0068]
It is to be noted that although in the fourth embodiment of the present
invention, propriety of establishment of an X2 link with a neighboring eNB
whenever the neighboring eNB is detected by the ANR function, the propriety
of establishment of the established X2 links may be determined only when the
25 number of established X2 links reaches a predetermined value as in the second
embodiment of the present invention.
[0069]
In this case, each eNB is provided with the database of Fig. 7 in
addition to the databases of Figs. 20 and 21. Additionally, in detecting the
30 neighboring eNB by means of the ANR function, the eNB may just perform
similar operation to the flow chart of Fig. 9. However, in step S12 of Fig. 9,
propriety of establishment of the established X2 links is determined using the
databases of Figs. 20 and 21.
[0070]
Next, a fifth embodiment of the present invention will be explained.
Although in the fourth embodiment of the present invention, each eNB holds
the database in which attribution information of each of the eNBs in the
mobile communication system is previously stored, in the fifth embodiment oi
5 the present invention, a server different from the eNB is made to hold a
database, and the server determines propriety of establishment of an X2 link
in each eNB using the database.
[0071]
Fig. 23 is a diagram showing a configuration of a mobile
10 communication system according to the fifth embodiment of the present
invention. As shown in Fig. 23, there exist the eNBs 101 and 102 in the fifth
embodiment of the present invention similarly to the first to fourth
embodiments of the present invention. The fifth embodiment is different
from the first to fourth embodiments of the present invention in a point where
15 the eNBs 101 and 102 are connected to a management server 150.
[0072]
Fig. 24 is a diagram showing a configuration of the management server
150 of Fig. 23. A determination unit 23 determines propriety of
establishment of an X2 link between eNBs based on eNB types of the eNBs.
20 A control unit 21 performs communication with the eNBs using a
communication unit 22. A storage unit 24 includes various databases, which
will be mentioned later.
[0073]
Fig. 25 is a database held by the management server 150 in the fifth
25 embodiment of the present invention. In the database of Fig. 25, previously
registered are an identifier (eNB ID) of each of eNBs in the mobile
communication system, an eNB type thereof, and eNB types in which
establishment of the X2 link should be restricted.
[0074]
30 Fig. 26 is a sequence diagram showing operation of the mobile
communication system according to the fifth embodiment of the present
invention. Hereinafter, with reference to Fig. 26, will be explained
operation in the eNB 101 detecting the eNB 102 by means of the ANR function
and trying to establish an X2 link.
[0075]
When an X2 link establishmcnt trigger by means of the ANR function
is gcnerated in the eNB 101 (step S7I), the eNB 101 inquires of the
management server 150 propriety of establishment of the X2 link with the
5 eNB 102 (step S72).
[0076]
When receiving the inquiry from the eNB 101, the management server
150 determines the propriety of establishment of the X2 link with the eNB 102
using the holding database (step S73). For example, the management server
10 150 refers to the database of Fig. 25 that the management server 150 has based
on an eNB ID of the source eNB 10 1 included in the inquiry from the eNB 10 1
and an eNB ID of the opposing eNB 102, and confirms whether or not an eNB
type of the opposing eNB 102 is included in the eNB types in which
establishment of the X2 link should be restricted in the eNB 101. It is to be
15 noted that the management server 150 may confirm whether or not an eNB
type of the eNB 101 is included in the eNB types in which establishment of
the X2 link should be restricted in the opposing eNB 102 to thereby determine
the propriety of establishment of the X2 link.
[0077]
20 If in step S73, the eNB type of the eNB 102 does not fall under the eNB
types in which establishment of the X2 link should be restricted, the
management server 150 transmits to the eNB 101 a response of approving
establishment of the X2 link with the eNB 102 (step S74). When receiving
the response, the eNB 101 performs an X2 link establishment procedure
25 (exchange of an X2 SETUP REQUEST message and an X2 SETUP RESPONSE
message after establishment of an SCTP link) with the eNB 102 (step S75).
[0078]
If in step S73, the eNB type of the eNB 102 falls under the eNB types
in which establishment of the X2 link should be restricted, the management
30 server 150 transmits to the eNB 101 a response of disapproving establishment
of the X2 link with the eNB 102 (step S74). When receiving the response,
the eNB 101 does not try to establish the X2 link with the eNB 102.
[0079]
Although in the above explanation, propriety determination of
establishment of the X2 link is performed based on the eNB type of the cNB,
similarly to the other embodiments of the prescnt invention, determination
criterion is not limited to the eNB type, and various attribution information of
the eNB can be used.
5 [0080]
As explained above, in the fifth embodiment of the present invention,
the management server 150 holds the database in which the eNB type of each
of the eNBs in the mobile communication system is previously stored, and
determines the propriety of establishment of the X2 link based on the eNB
10 type of the target eNB acquired from the database. Accordingly,
determination processing in the eNB becomes unnecessary, and it becomes
possible to save resources for the X2 link1SCTP link. In addition, unlike the
fourth embodiment of the present invention, it becomes unnecessary to
construct the above-described database inside the each eNB.
15 [0081]
It is to be noted that although in the fifth embodiment of the present
invention, propriety of establishment of an X2 link with a neighboring eNB is
determined by the management server 150 whenever the neighboring eNB is
detected by means of the ANR function, propriety of establishment of the
20 established X2 links may be determined by the management server 150 only
when the number of established X2 links reaches a predetermined value as in
the second embodiment of the present invention.
[0082]
In this case, each eNB is provided with the database of Fig. 7.
25 Additionally, in detecting the neighboring eNB by means of the ANR function,
the eNB inquires of the management server 150 propriety of establishment of
the established X2 links when the number of established X2 links has reached
the maximum number of X2 links in the self-eNB. The management server
150 determines the propriety of establishment of the established X2 links
30 using the database held by the self-server (compares eNB types in which
establishment of the X2 link should be restricted in the eNB as an inquiry
source with eNB types of the opposing eNBs having the established X2 links),
and returns a determination result to the eNB as the inquiry source. The eNB
as the inquiry source disconnects the X2 link in accordance with the
determination result of the management server 150.
[0083]
Next, a sixth embodiment of the present invention will be explained.
Although in the fifth embodiment of the present invention, the management
5 server 150 holds the database in which attribution information of each of the
eNBs in the mobile communication system is previously stored, in the sixth
embodiment of the present invention, the management server 150 need not
hold such database, and when receiving from the eNB an inquiry of propriety
of establishment of an X2 link with a neighboring eNB, the management
10 server 150 inquires attribution information of the neighboring eNB, and
determines the propriety of establishment of the X2 link. It is to be noted
that although a basic configuration of the sixth embodiment of the present
invention is the same as that of the fifth embodiment of the present invention,
the management server 150 inquires attribution information of the eNB and
15 acquires it in the following explanation, and thus it need not hold the database
of Fig. 25.
[0084]
Fig. 27 is a sequence diagram showing operation of a mobile
communication system according to the sixth embodiment of the present
20 invention. Fig. 28 is a database held by the management server 150 in the
sixth embodiment of the present invention. In the database of Fig. 28,
previously registered are an identifier (eNB ID) of each of eNBs in the mobile
communication system and an eNB type thereof in which establishment of the
X2 link should be restricted.
25 [0085]
Hereinafter, with reference to Fig. 27, will be explained operation in
the eNB 101 detecting the eNB 102 by means of the ANR function and trying
to establish an X2 link.
[0086]
30 When an X2 link establishment trigger by means of the ANR function
is generated in the eNB 101 (step S81), the eNB 101 inquires of the
management server 150 propriety of establishment of the X2 link with the
eNB 102 (step S82). When receiving the inquiry from the eNB 101, the
management server 150 inquires an eNB type of the eNB 102 (step S83). The
eNB 102 reports the eNB type of the eNB 102 to the management server 150
(step S84).
[0087]
The management server 150 determines propriety of establishment of
5 the X2 link between the eNBs 101 and 102 based on the acquired eNB type of
the eNB 102 (step S85). Namely, the management server 150 confirms the
eNB types in which establishment of the X2 link should be restricted in the
eNB 101 from an eNB ID of the source eNB 101 included in the inquiry from
the eNB 101, and the database of Fig. 28. The management server 150 then
10 confirms whether or not the eNB type of the eNB 102 is included in the eNB
typcs in which establishment of the X2 link should be restricted in the eNB
101 to thereby determine the propriety of establishment of the X2 link.
[0088]
If in step S85, the eNB type of the eNB 102 does not fall under the eNB
15 types in which establishment of the X2 link should be restricted, the
management server 150 transmits to the eNB 101 a response of approving
establishment of the X2 link with the eNB 102 (step S86). When receiving
the response, the eNB 101 performs an X2 link establishment procedure
(exchange of an X2 SETUP REQUEST message and an X2 SETUP RESPONSE
20 message after establishment of an SCTP link) with the eNB 102 (step S87).
[0089]
If in step S85, the eNB type of the eNB 102 falls under the eNB types
in which establishment of the X2 link should be restricted, the management
server 150 transmits to the eNB 101 a response of disapproving establishment
25 of the X2 link with the eNB 102 (step S86). When receiving the response,
the eNB 101 does not try to establish the X2 link with the eNB 102.
[0090]
Although the management server 150 holds the database of Fig. 28 in
the above explanation, it may hold a database of Fig. 29 instead of the
30 database of Fig. 28. In the database of Fig. 29, registered is information of
eNB type combinations in which establishment of the X2 link should be
restricted. In an example of Fig. 29, establishment of X2 links between
eNBs of the Macro eNB and the Pico eNB, e ~ Bosf the Macro eNB and the
HeNB, and eNBs of the Micro eNB and the HeNB is disapproved, respectively.
If an eNB type of the eNB 101 is included in the inquiry of step S82, the
management server 150 can determine propriety of establishment of the X2
link between the eNBs 101 and 102 using the database of Fig. 29 in step S85.
[009 11
5 In addition, although i n t h e above explanation, propriety determination
of establishment of the X2 link is performed based on the eNB type of the
eNB, similarly to the other embodiments of the present invention,
determination criterion is not limited to the eNB type, and various attribution
information of the eNB can be used.
10 [0092]
As explained above, in the sixth embodiment of the present invention,
when receiving from the eNB the inquiry of propriety of establishment of the
X2 link k i t h the neighboring eNB, the management server 150 inquires
attribution information of the neighboring eNB, and determines the propriety
15 of establishment of the X2 link. Accordingly, determination processing in
the eNB becomes unnecessary, and it becomes possible to save resources for
the X2 link/SCTP link. In addition, unlike the fifth embodiment of the
present invention, it becomes unnecessary to construct inside the management
server a database in which attribution information of each of the eNBs in the
20 mobile communication system is previously stored. In addition, the
management server 150 inquires attribution information of the eNB and
acquires i t , the sixth embodiment of the present invention is suitable also for
the case of using dynamically changing information, such as the number of
users, for the propriety determination of establishment of the X2 link.
25 [0093]
It is to be noted that although in the sixth embodiment of the present
invention, propriety of establishment of an X2 link with a neighboring eNB is
determined by the management server 150 whenever the neighboring eNB is
detected by means of the ANR function, propriety of establishment of the
30 established X2 links may be determined by the management server 150 only
when the number of established X2 links reaches a predetermined value as in
the second embodiment of the present invention.
[0094]
In this case, each eNB is provided with the database of Fig. 7.
Additionally, in detecting the neighboring eNB by means of the AN11 function,
the eNB inquires of the management server 150 propriety of establishment of
the established X2 links when the number of established X2 links has reached
the maximum number of X2 links in the self-eNB. The management server
5 150 inquires an eNB type of each of opposing eNB? having the established X2
links and acquires it, determines the propriety of establishment of the
established X2 links (compares eNB types in which establishment of the X2
link should he restricted in the eNB as an inquiry source with the eNB types of
the opposing eNBs having the established X2 links), and returns a
10 determination result to the eNB as the inquiry source. The eNB as the
inquiry source disconnects the X2 link in accordance with the determination
result of the management server 150.
[0095]
' Next, a seventh embodiment of the present invention will be explained.
15 Although in the sixth embodiment of the present invention, the management
server 150 inquires and acquires attribution information of the neighboring
eNB when receiving from the eNB the inquiry of propriety of establishment of
the X2 link with the neighboring eNB, in the seventh embodiment of the
present invention, each eNB regularly reports attribution information to the
20 management server 150, or the management server 150 regularly acquires the
attribution information of the each eNB.
[0096]
It is to be noted that a basic configuration of the seventh embodiment
of the present invention is the same as that of the fifth embodiment of the
25 present invention. However, since attribution information is regularly
acquired from each eNB in the seventh embodiment of the present invention,
the embodiment is more suitable for the case of using dynamically changing
information, such as the number of users. Therefore, the number of users is
used as attribution infdrmation in the following explanation. Accordingly,
30 in the seventh embodiment of the present invention, unlike the fifth
embodiment of the present invention, the management server 150 is provided
with a database in which the number of users of each eNB is stored instead of
the database of Fig. 25, and the database is updated whenever information of
the number of users is acquired from the each eNB.
100971
Fig. 30 is a sequence diagram showing operation of a mobile
communication system according to the seventh embodiment of thc present
invention. Fig. 31 is a database held by the management server 150 in the
5 seventh embodiment of the present invention. In the database of Fig. 3 1,
stored are an identifier (eNB ID) of each of eNBs in the mobile
communication system and information of the number of users thereof. As
mentioned above, the database is updated whenever information of the number
of users is acquired from each eNB.
10 [0098]
Hereinafter, with reference to Fig. 30, will be explained operation of
the mobile communication system according to the seventh embodiment of the
present invention.
[0099]
15 Each of the eNBs 101 and 102 regularly reports the number of users of
the self-eNB to the management server 150 (steps S91 and S92). As
described above, instead of each eNB autonomously reporting the number of
users to the management server 150, the management server 150 may regularly
inquire of the each eNB. In this case, the management server 150 regularly
20 sends a report request of the number of users to the eNBs 101 and 102 (steps
S93 and S95). In contrast with this, each of the eNBs 101 and 102 regularly
reports the number of users of the self-eNB to the management server 150
(steps S94 and S96). It is to be noted that when receiving a report of the
number of users, the management server 150 updates the database of Fig. 31.
25 [OlOO]
Next, will be explained operation in the eNB 101 detecting the eNB
102 by means of the ANR function and trying to establish an X2 link. When
an X2 link establishment trigger by means of the ANR function is generated in
the eNB 101 (step S97), the eNB 101 inquires of the management server 150
30 propriety of establishment of the X2 link with the eNB 102 (step S98).
[OlOl]
The management server 150 determines propriety of establishment of
the X2 link between the eNBs 101 and 102 based on the information of the
number of users in the database of Fig. 31 (step S99). Namely, the
management server 150 confirms thc number of users of the eNB 102 from an
eNB ID of the eNB 102 included in the inquiry from the cNB 101, and the
database of Fig. 3 1. The management server 150 compares the number of
users of the eNB 102 with a predetermined threshold value, and performs
5 propriety determination of establishment of the X2 link.
[O 1021
If the number of users of the eNB 102 is not less than the threshold
value in step S99, the management server 150 transmits to the eNB 101 a
response of approving establishment of the X2 link with the eNB 102 (step
10 S100). When receiving the response, the eNB 101 performs an X2 link
establishment procedure (exchange of an X2 SETUP REQUEST message and
an X2 SETUP RESPONSE message after establishment of an SCTP link) with
the eNB 102 (step S101).
[0103]
15 If the number of users of the eNB 102 is less than the threshold value
in step S99, the management server 150 transmits to the eNB 101 a response
of disapproving establishment of the X2 link with the eNB 102 (step S100).
When receiving the response, the eNB 101 does not try to establish the X2
link with the eNB 102.
20 [O104]
Although in the above explanation, propriety determination of
establishment of the X2 link is performed based on the number of users of the
eNB, similarly to the other embodiments of the present invention,
determination criterion is not limited to the number of users, and various
25 attribution information of the eNB can be used.
[0 10.51
As explained above, in the seventh embodiment of the present
invention, the management server 150 regularly acquires the attribution
information of the each eNB, and when receiving from the eNB an inquiry of
30 propriety of establishment of an X2 link with a neighboring eNB, the
management server 150 determines the propriety of establishment of the X2
link. : Accordingly, determination processing in the eNB becomes
unnecessary, and it becomes possible to save resources for the X2 link/SCTP
link. In addition, the management server 150 need not inquire attribution
information of the eNB at the time of receiving the inquiry of propricly of
establishment of the X2 link as in the sixth embodiment of the present
invention. In addition, since attribution information is regularly acquired
from each eNB, the embodiment is.more suitable for the case of using
5 dynamically changing information, such as the number of users..
[0106]
It is to be noted that although in the seventh embodiment of the present
invention, propriety of establishment of an X2 link with a neighboring eNB is
determined by the management server 150 whenever the neighboring eNB is
10 detected by means of the ANR function, propriety of establishment of the
established X2 links may be determined by the management server 150 only
when the number of established X2 links reaches a predetermined value as in
the third embodiment of the present invention.
[0 1 071
15 In this case, each eNB is provided with the database of Fig. 7.
Additionally, in detecting the neighboring eNB by means of the ANR function,
the eNB inquires of the management server 150 propriety of establishment of
the established X2 links when the number of established X2 links, for
example, has reached the maximum number of X2 links in the self-eNB. In
20 this inquiry, included is an eNB ID of each of opposing eNBs having the
established X2 links. The management server 150 confirms the number of
users of each of the opposing eNBs from the eNB ID and the database of Fig.
3 1, determines propriety of establishment of the established X2 links based on
the number of users, and selects the X2 link that should be disconnected.
25 Specifically, selected is the X2 link with the opposing eNB that has the lowest
number of users or the lowest number of users less than the threshold value.
The management server 150 returns the determination result to the eNB as an
inquiry source. The eNB as the inquiry source disconnects the X2 link in
accordance with the determination result of the management server 150.
30 [0108]
While the present invention has been described above with reference to
exemplary embodiments, the present invention is not limited to the exemplary
embodiments stated above. The configuration and details of the present
invention can be modified in various manners which can be understood by
those skillcd in the art within the scope of the invention. For example, the
following forms may he employed.
[O109]
(Supplementary note 1)
5 A radio base station in a mobile communication system, including
determination means for determining propriety of establishment of an
established logical interface based on attribution information of a neighboring
radio base station notification of which is performed from the neighboring
radio base station in establishment of the established logical interface, when
10 the number of established logical interfaces with the neighboring radio base
station has reached a predetermined value.
[OllO]
(Supplementary note 2)
A radio base station in a mobile communication system, including:
transmission means for regularly notifying of attribution information
of the self-base station a neighboring radio base station in which a logical
interface has been established with the self-base station; and
determination means for determining propriety of establishment of an
established logical interface based on the attribution information notification
20 of which is performed from the transmission means of the neighboring radio
base station, when the number of established logical interfaces with the
neighboring radio base station has reached a predetermined value.
[ O l l l ]
(Supplementary note 3)
25 A radio base station in a mobile communication system, including:
storage means for storing attribution information of each of other radio
base stations; and
determination means for determining propriety of establishment of an
30 established logical interface based on the attribution information of a
neighboring radio base station stored in the storage means, when the number
of established logical interfaces with the neighboring radio base station has
reached a predetermined value.
[0112]
(Supplementary note 4)
A server that is connected to radio base stations in a mobile
communication system, including:
storage means for storing attribution information of each of the radio
5 base stations; and
determination means for determining propriety of establishment of an
established logical interface based on the attribution information of a
neighboring radio base station stored in the storage means, when a request of
propriety determination of establishment of the established logical interface
10 is received from a radio base station in which the number of established
logical interfaces with the neighboring radio base station has reached a
predetermined value among the radio base stations.
[0113]
(Supplementary note 5)
15 A server that is connected to radio base stations in a mobile
communication system, including:
means for acquiring attribution information of a neighboring radio
base station from the neighboring radio base station, when a request of
propriety determination of establishment of an established logical interface is
20 received from a radio base station in which the number of established logical
interfaces with the neighboring radio base station has reached a predetermined
value among the radio base stations; and
determination means for determining propriety of establishment of the
established logical interface based on the acquired attribution information.
25
[OI 141
(Supplementary note 6)
A server that is connected to radio base stations in a mobile
communication system, including:
3 0 means for regularly acquiring attribution information of each of the
radio base stations; and
determination means for determining propriety of establishment of a
logical interface based on the acquired attributio~i nformation of a
neighboring radio base station, when a request of propriety determination of
establishment of the logical interface with the neighboring radio base station
is received from one of the radio base stations.
[0115]
(Supplementary note 7)
5 A server that is connected to radio base stations in a mobile
communication system, including:
means for regularly acquiring attribution information of each of the
radio base stations; and
determination means for determining propriety of establishment of an
10 established logical interface based on the acquired attribution information of
a neighboring radio base station, when a request of propriety determination of
establishment of the established logical interface is received from a radio base
station in which the number of established logical interfaces with the
neighboring radio base station has reached a predetermined value among the
15 radio base stations.
[0116]
(Supplementary note 8)
A mobile communication system including a radio base station, in
which the radio base station includes determination means for determining
20 propriety of establishment of a logical interface with a neighboring radio base
station based on attribution information of the neighboring radio base station.
[OI 173
(Supplementary note 9)
The mobile communication system according to Supplementary note 8,
25 in which the determination means determines propriety of establishment of a
logical interface based on the attribution information notification of which is
performed from a neighboring radio base station in establishment of the
logical interface with the neighboring radio base station.
[0118]
30 (Supplementary note 10)
The mobile communication system according to Supplementary note 8,
in which
the radio base station includes storage means for storing attribution
information of each of other radio base stations, and in which
the determination means determines propriety of establishment of a
logical interface based on attribution information of a neighboring radio base
station stored in the storage means in establishment of the logical interface
with the neighboring radio base station.
5 [0119]
(Supplementary note 11)
A mobile communication system, including:
radio base stations; and
a server that is connected to the radio base stations, in which
thc server includes determination means for determining propriety of
establishment of a logical interface between the radio base stations based on
attribution information of the radio base stations.
[0120]
(Supplementary note 1'2)
15 The mobile communication system according to Supplementary note
11, in which
the server includes storage means for storing attribution information of
each of the radio base stations, and in which
when receiving from one of the radio base stations a request of
20 propriety determination of establishment of a logical interface with a
neighboring radio base station, the determination means determines propriety
of establishment of the logical interface based on attribution information of
the neighboring radio base station stored in the storage means.
[0121]
25 (Supplementary note 13)
The mobile communication system according to Supplementary note
11. in which
the server includes means for acquiring attribution information of a
neighboring radio base station from the neighboring radio base station, when
30 receiving from one of the radio base stations a request of propriety
determination of establishment of a logical interface with the neighboring
radio base station, and in which
the determination means determines propriety of establishment of the
logical interface based on the acquired attribution information.
[O 1221
(Supplementary note 14)
Thc mobile communication system according to Supplementary note
11, in which
5 the server includes means for regularly acquiring attribution
information of each of the radio base stations, and in which
when receiving from one of the radio base stations a request of
propriety determination of establishment of a logical interface with a
neighboring radio base station, the determination means determines propriety
10 of establishment of the logical interface based on the acquired attribution
information of the neighboring radio base station.
[O 1231
The present application claims priority rights of and is based on
Japanese Patent Application No. 201 1-272879 filed on December 14, 201 1 in
15 the Japanese Patent Office, the entire contents of which are hereby
incorporated by reference.
Reference Signs List
[0 1241
20 11, 21 Control Unit
12, 22 Communication Unit
13, 23 Determination Unit
14, 24 Storage Unit
15 Radio Communication Unit
25 101,102 eNB
150 Management Server
35
CLAIMS
1. A radio base station of a mobile communication system,
the radio base station comprising a determination means for
5 determining whether it is proper or not to establish a logical interface with a
neighboring radio base station by using a attribution information of the
neighboring radio base station.
2. The radio base station according to Claim 1,
10 wherein, the determination means determines, befqre establishing a
logical interface with the neighboring radio base station, whether it is proper
or not to establish the logical interface by using the attribution information
notification of which is performed from the neighboring radio base station.
15 3 . The radio base station according to Claim 1, comprising storage means
for storing attribution information of each of other radio base stations,
wherein, the determination means determines, before establishing a
logical interface with the neighboring radio base station, whether it is proper
or not to establish the logical interface by using the attribution information
20 stored in the storage means.
4. An operation control method for a radio base station of a mobile
communication system,
the operation control method comprising a step of determining whether
25 it is proper or not to establish a logical interface with a neighboring radio
base station by using a attribution information of the neighboring radio base
station.
5. A server that is connected to radio base stations of a mobile
30 communication system,
the server comprising a determination means for determining whether
it is proper or not to establish a logical interface with a neighboring radio
base station by using a attribution information of the neighboring radio base
station.
6 . Thc server according to Claim 5, comprising storage means for storing
attribution information of each of the radio base stations,
wherein, when receiving from one of the radio base stations a request
5 whether it is proper or not to establish a logical interface with a neighboring
radio base station, the determination means determines the logical interface
by using a attribution information of the neighboring radio base station stored
in the storage means.
10 7. The server according to Claim 5, comprising means for acquiring
attribution information of a neighboring radio base station from the
neighboring radio base station, when receiving from one of the radio base
stations a request whether it is proper or not to establish a logical interface
with the neighboring radio base station,
15 wherein, the determination means determines the logical interface by
using the acquired attribution information.
8. An operation control method for a server that is connected to radio
base stations of a mobile communication system,
2 0 the operation control method comprising a step of determining whether
it is proper or not to establish a logical interface with a neighboring radio
base station by using a attribution information of the neighboring radio base
station.
25 9. A mobile communication system, comprising:
radio base stations; and
determination means for determining whether it is proper or not to
establish a logical interface with the radio base stations by using a attribution
information of the radio base stations.
30
10. An operation control method for a mobile communication system,
the operation control method comprising a step of determining whether it is
proper or not to establish a logical interface with the radio base stations by
using a attribution information of the radio base stations.