[Document Name] DESCRIPTION
[Ti t le of Invent ion]
COMMUNICATION SYSTEM, RADIO BASE STATION, TRAFFIC
LOAD DISTRIBUTION METHOD, AND STORAGE MEDIUM ON WHICH
PROGRAM HAS BEEN STORE5 D
[Technical Field]
[0001]
The present invent ion relates to a communicat ion sys tem, a radio
base stat ion, a t raff ic load distr ibut ion method, and a storage medium
10 storing a t raffic load distribut ion program, that dist ribute traffic loads
among base stat ions .
[Background Art]
[0002]
A backhaul (hereinaf ter, refer red to as a mobi le ba ckhaul) between
15 radio base stat ions and a mobi le core network may include a plural i ty of
l inks. Fig. 12 is a block diagram i l lust rat ing one example of the mobi le
backhaul . The mobi le backhaul is divided into an access l ink, an
aggregat ion l ink, and a met ro l ink. The access l ink is a l ink that
accommodates a radio base stat ion connected to a relay apparatus disposed
20 in an access area. The aggregat ion l ink is a l ink that accommodates a
plural i ty of radio base stat ions connected to relay apparatuses dispos ed in
the access area and a radio base stat ion (not i l lust rated in Fig. 12) disposed
in an aggregat ion area. The metro l ink is a l ink in a met ro area and is a
l ink to t ransfer a large amount of mobi le data t raffic of the plural i ty of
25 radio base stat ions t ransfer red via the aggregat ion l ink to a mobi le core
network. Hereinafter, a communicat ion resource in the backhaul wi l l be
refer red to as a backhaul resource. Fur ther, a traffic load in the backhaul
resource wi l l be referred to as a backhaul resource lo ad.
[0003]
2
As a method for dist ribut ing backhaul resource loads, there is, for
example, MLB (Mobi l i ty Load Balancing) executed between eNBs
(evolved Node Bs) . The eNB is a radio base stat ion corresponding to LTE
(Long Term Evolut ion). MLB is executed in accordance wi th procedures
indicated in 1 to 4 described below5 .
[0004]
1. Via an X2 l ink between eNBs, there is executed resource status
report ing processing, specifical l y, Resource Status Repor t ing Ini t iat ion
Procedure descr ibed in technical speci ficat i ons (TS 36.423 Version 11.5.0)
10 of 3GPP (3rd Generat ion Partnership Project) .
[0005]
Fig. 13 is a sequence diagram i l lust rat ing resource status report ing
processing between eNBs. In the resource status report ing processing, as
i l lust rated in Fig. 13, a resource status request message (X2: RESOURCE
15 STATUS REQUEST message) is t ransmi t ted f rom an eNB 1 to an eNB
adjacent thereto (hereinafter, refer red to as an adjacent eNB), i .e. an eNB 2.
Then, f rom the eNB 2 to the eNB 1, a response message (X2: RESOURCE
STATUS RESPONSE message) to the resource status request message is
transmi t ted.
20 [0006]
Fig. 14 is an i l lust rat ive diagram i l lustrat ing a st ructure of the
resource status request message. The eNB 1 designates load informat ion
of the adjacent eNB (eNB 2) that establ ishes an X2 l ink as a measurement
object in the resource status request message. Speci fical l y, as i l lust rated
25 i n Fi g . 1 4 , t h e eNB 1 d es i g n at e s “ TN L ( Tr an s p o r t Net wo r k La y er ) l o ad In d
P er i o d i c ” as the parameter “R ep o r t Ch a r a ct e r i s t i cs (me as u r emen t object
i t ems ) ” o f t h e r e s o u r ce s t at u s r eq u es t mes s a g e. T h er eb y, t h e eNB 1
becomes able to periodical ly receive load informat ion of the eNB 2. In
“Re p o r t Ch ar a ct er i s t i cs , ” u p t o f o u r p i e ce s o f l o a d i n f o rma t i o n c an b e
3
designated. In the present example, as o n e t h e r eo f , “TNL l o ad In d
P er i o d i c ” i s i n cl u d e d .
[0007]
2. The eNB 1 receives a resource status update message (X2:
RESOURCE STATUS UPDATE message) f rom the adjacent eNB5 .
[0008]
Fig. 15 is an i l lust rat ive diagram i l lustrat ing a st ructure of the
resource status update message. The resource status update message
r e c ei v ed b y t h e eNB 1 i n cl u d es “S 1 TNL Lo ad In d i c at o r ” as i l l u s t r at ed i n
10 Fi g . 1 5 . “S 1 TNL Lo a d In d i ca t o r ” i s l o ad i n f o rmat i o n o f an S 1 t r a n s p o r t
network layer (hereinafter, referred to as S1 n etwork load informat ion) .
The S1 network load informat ion is informat ion indicat ing a backhaul
resource load of a l ink, i .e. an access l ink between an eNB and a fi rst -hop
relay apparatus f rom the eNB. A value of the S1 network load
15 informat ion is indicat e d b y a n y o n e o f f o u r s t a g es o f “ LowLo a d , ”
“Med i umLo ad , ” “Hi g h Lo ad , ” an d “Ov e r l o ad . ”
[0009]
3. The eNB 1 changes , when a load of TNL exceeds a certain
threshold, a handover at t ribute value (a value of a parameter for
20 control l ing Handover described in the technical specif icat ions) to swi tch a
cel l where a radio terminal is located f rom a cel l of the eNB 1 to a cel l of
an adjacent eNB having a low load, i .e. to execute Handover. At that
t ime, the eNB 1 designates the cel l of the adjacent eNB having a low lo ad
as a handover dest inat ion on the basis of the S1 network load informat ion
25 received from the adjacent eNB. Herein, i t is assumed that the eNB 1
designates a cel l of the eNB 2.
[0010]
4. The eNB 1 handovers the cel l where the radio terminal is located
from the cel l of the eNB 1 to the cel l of the eNB 2 to distribute the
4
backhaul resource load.
[0011]
PTL 1 describes a technique rendering route select ion processing
for appropriately distribut ing traffic possible by adding congest ion
informat ion of l ines to a load distr ibut ion processing condi t ion in an I5 P
network.
[Ci tat ion List]
[Patent Li terature]
[0012]
10 [PTL 1] Japanese Laid-open Patent Publ icat ion No. 2005 -252766
[Summary of Invent ion]
[Technical Problem]
[0013]
Here, i t is assumed that the eNB 1 and the eNB 2 use access l inks
15 differing from each other. Further, i t is assumed that aggregat ion l inks
located ahead of the access l inks used by the eNB 1 and the eNB 2,
respect ivel y, are the same and also, in the aggregat ion l ink, a backhaul
resource load increases and congest ion occurs.
[0014]
20 When a backhaul resource load of the access l ink used by the eNB 1
is high and a backhaul resource load of the access l ink used by the eNB 2 is
low, a load distr ibut ion funct ion works in each eNB. In other words, the
procedures 3 to 4 are executed. Thereby, the cel l where the radio
terminal is located is handovered from the cel l of the eNB 1 to the cel l of
25 the eNB 2. As a resul t , the backhaul resource loads in the access l inks
are dist ributed. However, in the aggregat ion l ink, the backhaul resource
load is unchanged and therefore, congest ion is not el iminated. Therefore,
i t is di fficul t to avoid a throughput decrease of the radio terminal in the
cel l of the eNB 2 of the handover dest inat ion. The reason is that a value
5
i n d i cat e d b y “S 1 TNL Lo ad In d i c at o r ” i n cl u d ed i n t h e r e s o u r c e s t at u s
update message indicates a backhaul resource load of the access l ink. In
other words, load distribut ion considering load informat ion of the
aggregat ion l ink is not executed.
[0015 5]
Fig. 16 is a block diagram i l lustrat ing an out l ine of a radio
communicat ion network. In the radio communicat ion network i l lust rated
in Fig. 16, radio base stat ions (eNBs 103 to 105) are connected to an EPC
(Evolved Packet Core) network (hereinaf ter, r efer red to simply as an EPC)
10 100 via l inks 111 to 115 and relay apparatuses 101 to 102. The eNB 103
and the eNB 104 are connected to the relay apparatus 101. The eNB 105
is connected to the relay apparatus 102. Further, the relay apparatuses
101 to 102 are connected to the EPC 100. The eNB 103 and the eNB 104,
and the eNB 104 and the eNB 105 are connected via an X2 l ink,
15 respect ivel y.
[0016]
Here, it is assumed that a radio terminal 106 is located in a cel l of
the eNB 104 (a cel l 108 i l lustrated in Fig. 16) . The radio terminal 106 is
connected to the EPC 100 via the eNB 104 and the relay apparatus 101.
20 Further, a state of a backhaul resource load in the l ink 111 that connects
t h e E PC 1 0 0 a n d t h e r el a y ap p a r at u s 1 0 1 i s “Hi g h Lo a d . ” A s t at e o f a
backhaul resource load in the l ink 112 that connects the EPC 100 and the
r el a y a p p ar at u s 1 0 2 i s “Med i umLo a d . ” A s t at e o f a b a c k h au l r es o u r c e
load in the l ink 113 that connects the relay apparatus 101 and the eNB 103
25 i s “ LowLo a d . ” A s t at e o f a b a ck h au l r es o u r c e load in the l ink 114 that
co n n e ct s t h e r el a y a p p a r a t u s 1 0 1 an d t h e eNB 1 0 4 i s “Hi g h Lo a d . ” A s t a t e
of a backhaul resource load in the l ink 115 that connects the relay
ap p a r a t u s 1 0 2 an d t h e eNB 1 0 5 i s “Me d i umLo ad . ”
[0017]
6
Fo r ex amp l e , “S 1 TNL Lo a d In d i ct o r , ” i . e. a v al u e o f S 1 n et wo r k
load informat ion received by the eNB 104 f rom the eNB 103 indicates the
backhaul resource load of the l ink 113. Therefore, the eNB 104 acquires
“ LowLo a d ” a s t h e v al u e o f S 1 n et wo r k l o ad i n f o rmat i o n o f t h e eNB 1 0 3 .
In the simi lar manner, a value of S1 network load informat ion received b5 y
the eNB 103 f rom the eNB 1 0 4 i s “Hi g h Lo ad . ” Fu r t h er, a v al u e o f S 1
network load informat ion received by the eNB 104 f rom the eNB 105 is
“Med i umLo ad . ”
[0018]
10 It is assumed that the eNB 103, the eNB 104, and the eNB 105 share
respect ive pieces of load informat ion and the eNBs determine which
adjacent cel l is designated as a handover dest inat ion of the radio terminal
106 on the basis of values indicated by the respect ive pieces of load
informat ion. Herein, the eNBs are assumed to share only S1 network load
15 informat ion. At that t ime, when a load of the eNB 104 increases to some
extent , the eNB 104 determines a cel l of the eNB 103 (a cel l 107 i l lust rated
in Fig. 16) as a handover dest inat ion sinc e the value of S1 network load
i n f o rmat i o n o f t h e eNB 1 0 3 i s “ LowLo a d . ”
[0019]
20 Fig. 17 is an i l lustrat ive diagram i l lust rat ing how the eNBs 103 to
104 handover a radio terminal f rom a cel l where the radio terminal is
located (the cel l 108) to another cel l (the cel l 107). As i l lust rated in Fig.
17, in order to easi ly handover the radio terminal 106 from the cel l 108 to
the cel l 107, the eNB 103 and the eNB 104 cooperate to change a set t ing of
25 a handover at t ribute value. In other words, the eNB 103 and the eNB 104
each change a set t ing of a handover at tr ibute value and move a handover
boundary to cause the cel l 107 to become a handover dest inat ion. An
area of the cel l 107 prior to the change of the handover at t ribute value is
i l lust rated using a dashed l ine in Fig. 17. When the radio terminal 106 is
7
located in the cel l 107, a backhaul resource load of the l ink 114 is reduced
and a backhaul resource load of the l ink 113 is increased. Thereby, the
loads are distributed between the l ink 113 and the l ink 114. However, a
backhaul resource load of the l ink 111 in which those of the l ink 113 and
t h e l i n k 11 4 ar e a g g r e g at ed i s o r i gi n al l y “Hi g h Lo ad . ” T h er e f o r e , ev 5 en
when the loads are distributed between the l ink 113 and the l ink 114, the
load of the l ink 111 is n o t r ed u c ed an d r emai n s “Hi g h Lo ad . ” T h er e f o r e,
even when the cel l where the radio terminal 106 is located is handovered, i t
may be di fficul t to avoid a throughput decrease of the radio terminal 106.
10 [0020]
As an o p t imi z at i o n met h o d o f MLB, t h e r e i s “E n h a nced Mobi l i ty
Lo a d Bal an ci n g Op t imi z at i o n i n LT E ” p r es en t ed b y NS N (No k i a S o l u t i o n s
and Networks) at an internat ional symposium (2012 IEEE 23rd
Internat ional Symposium on Personal , Indoor and Mobi le Radio
15 Communicat ions -(PIMRC) ). In this opt imizat ion meth od, a cel l of a
handover dest inat ion is determined on the basis of a f requency band
ut i l izable for each adjacent radio base stat ion. Here, the f requency band
ut i l izable for each adjacent radio base stat ion is defined by a di fference
between al l of the transport capaci t ies al located to radio base stat ions and
20 a GBR (Guaranteed Bi t Rate) sum of act ive bearers. The GBR sum of
act ive bearers is a sum of GBRs of the act ive bearers including a
communicat ion overhead based on S1 Inter face protocol .
[0021]
The opt imizat ion method uses a transport capaci ty considering only
25 a backhaul resource load of a l ink between a radio base stat ion and a
first -hop relay apparatus f rom the radio base stat ion , i .e. an access l ink.
Therefore, the opt imizat ion method does not con sider a backhaul resource
load of an aggregat ion l ink located ahead of the access l ink. A case in
which a backhaul resource load of the aggregat ion l ink located ahead of the
8
access l ink is considered and a case in which the above mat ter is not
considered are different in a frequency band defined by a di fference
between a transport capaci ty and a GBR sum of act ive bearers. As a
resul t , even when on the basis of the opt imizat ion method, MBL is
executed between radio base stat ions, i t is di fficul t to avoid a ggregat io5 n
l ink congest ion and a throughput decrease of a radio terminal .
[0022]
Accordingl y, the present invent ion is intended to provide a
communicat ion system, a radio base stat ion, a traffic load distr ibut ion
10 method, and a storage medium storing a t ra ffic load dist ribut ion program,
that can avoid backhaul congest ion and a throughput decrease of a
terminal .
[Solut ion to Problem]
[0023]
15 A communicat ion system, according to the present invent ion,
comprises radio base stat ions and a management cont rol app aratus.
The management control apparatus includ es:
a fi rst communicat ion means for col lect ing backhaul resource load
informat ion indicat ing traffic loads of respect ive l inks in a backhaul
20 between the radio base stat ions and a core network from relay appa ratuses
that relay communicat ions between the radio base stat ions and the core
network;
an operat ion means for extract ing, for each radio base stat ion, a
bot t leneck l ink having the highest load among respect ive l inks in a
25 backhaul between a radio base sta t ion and the core network on the basis of
the backhaul resource load informat ion col lected by the fi rst
communicat ion means; and
a second communicat ion means for transmi t t ing backhaul resource
load informat ion of the bot t leneck l ink to the radio base stat ions.
9
The radio base stat ion includes
an execut ion means for execut ing dist ribut ion of traff ic loads
among the radio base stat ions on the basis of backhaul resource load
informat ion of a bot t leneck l ink in a backhaul between an own stat ion and
the core network received f rom the management cont rol apparatus5 .
[0024]
A radio base stat ion, according to the present invent ion, comprises:
a communicat ion means for receiving, f rom a management control
apparatus that manages communicat ion resources in a backhaul between
10 radio base stat ions and a core network, backhaul resource load informat ion
of respect ive l inks in a backhaul between an own stat ion and the core
network;
an operat ion means for extract ing a bot t leneck l ink having the
highest load among respect ive l inks in a backhaul between an own stat ion
15 and the core network on the basis of the backhaul resource load
informat ion received f rom the management cont rol apparatus; and
an execut ion means for execut ing dist ribut ion of traff ic loads
among the radio base stat ions on the basis of backhaul resource load
informat ion of the bot t leneck l ink.
20 [0025]
A traffic load dist ribut ion method, according to the present
invent ion, comprises:
receiving, f rom a management cont rol apparatus that manages
communicat ion resources in a backhaul between radio base stat ions and a
25 core network, backhaul resource load informat ion of respect ive l inks in a
backhaul between an own stat ion and the core network;
extract ing a bot t leneck l ink having the highest load among
respect ive l inks in a backhaul between an own stat ion and the core network
on the basis of the backhaul resource load informat ion received from the
10
management cont rol apparatus; and
execut ing dist ribut ion of t raffic loads among the radio base stat ions
on the basis of backhaul resource load informat ion of the bot t leneck l ink .
[0026]
A storage medium, according to the present invent ion, stores 5 a
traffic load distr ibut ion program, that causes
a computer to execute:
processing for receiving, from a management cont rol appa ratus that
manages communicat ion resources in a backhaul between radio base
10 stat ions and a core network, backhaul resource load informat ion of
respect ive l inks in a backhaul between an own stat ion and the core
network;
processing for extract ing a bot t lene ck l ink having the highest load
among respect ive l inks in a backhaul between an own stat ion and the core
15 network on the basis of the backhaul resource load informat ion received
from the management cont rol apparatus; and
processing for execut ing distribut i on of t raffic loads among the
radio base stat ions on the basis of backhaul resource load informat ion of
the bot t leneck l ink.
20 [Advantageous Effects of Invent ion]
[0027]
According to the present invent ion, i t is possible to avoid backhaul
congest ion and a throughput decrease of a terminal .
[Brief Descript ion of Drawings]
25 [0028]
[Fig. 1] Fig. 1 is a block diagram i l lust rat ing a configurat ion of a
first exemplary embodiment of a radio communicat ion system according to
the present invent ion.
[Fig. 2] Fig. 2 i s a block diagram i l lustrat ing a configurat ion of the
11
first exemplary embodiment of a radio base stat ion according to the present
invent ion.
[Fig. 3] Fig. 3 is a block diagram i l lustrat ing a configurat ion of the
first exemplary embodiment of a management control apparatus according
to the present invent ion5 .
[Fig. 4] Fig. 4 is an i l lust rat ive diagram i l lustrat ing one example of
informat ion represent ing a conversion algorism to convert backhaul
resource load informat ion to S1 network load informat ion.
[Fig. 5] Fig. 5 is a flowchart i l lust rat ing operat ions f rom col lect ing
10 backhaul resource load informat ion of respect ive l inks for an eNB to
extract ing a bot t leneck l ink using an NMS.
[Fig. 6] Fig. 6 is an i l lust rat ive diagram i l lustrat ing one example of
backhaul resource load informat ion of respect ive l inks between an eNB and
an EPC.
15 [Fig. 7] Fig. 7 is a sequence diagram i l lustrat ing an operat ion for
transmi t t ing backhaul resource load informat ion after conversion to an
eNB using an NMS.
[Fig. 8] Fig. 8 is a block diagram i l lust rat ing a configurat ion of a
second exemplary embodiment of a radio base stat ion according to the
20 present invent ion.
[Fig. 9] Fig. 9 is an i l lust rat ive diagram i l lustrat ing one example of
a structure of a resource status request messag e designated wi th addi t ive
IEs.
[Fig. 10] Fig. 10 is a block diagram i l lust rat ing a minimal
25 configurat ion of the communicat ion system according to the present
invent ion.
[Fig. 11] Fig. 11 is a block diagram i l lustrat ing a minimal
configurat ion of the radio base stat ion according to the present invent ion.
[Fig. 12] Fig. 12 is a block diagram i l lustrat ing one example of a
12
mobi le backhaul .
[Fig. 13] Fig. 13 is a sequence diagram i l lust rat ing resource status
report ing processing between eNBs.
[Fig. 14] Fig. 14 is an i l lustrat ive diagram i l lustrat ing a structure of
a resource status request message5 .
[Fig. 15] Fig. 15 is an i l lustrat ive diagram i l lustrat ing a structure of
a resource status update message.
[Fig. 16] Fig. 16 is a block diagram i l lust rat ing an out l ine of a radio
communicat ion network.
10 [Fig. 17] Fig. 17 is an i l lust rat ive diagram i l lust rat ing how an eNB
handovers a radio terminal f rom a cel l where the radio terminal is located
to another cel l .
[Descript ion of Embodiments]
[0029]
15 Fi rst Exemplary Embodiment
A first exemplary embodiment of the present invent ion wi l l be
described wi th reference to the drawings.
[0030]
Fig. 1 is a block diagram i l lust rat ing a configurat ion of the fi rst
20 exemplary embodiment of a radio communicat ion system according to the
present invent ion. The radio communicat ion system i l lust rated in Fig. 1
includes a management cont rol apparatus (hereinafter, refer red to as an
NMS (Network Management System) ) 201 that manages backhaul
resources and radio base stat ions (eNBs 211 to 213). The eNBs 211 to
25 213 are connected to an EPC 240 via relay apparatuses 221 to 226. The
NMS 201 is communicable to each eNB. Fur ther, the NMS 201 is
communicable to each relay apparatus. It should be noted that in Fig. 1,
three eNBs and six relay apparatuses are exempl i fied, but any number of
eNBs and relay apparatuses may be provided.
13
[0031]
Fig. 2 is a block diagram i l lust rat ing a configurat ion of the fi rst
exemplary embodiment of a radio base stat ion according to the present
invent ion. As i l lustrated in Fig. 2, the radio base stat ions (eNBs 211 to
213) each include a radio communicat ion processing uni t 300, an inter -eN5 B
message processing uni t 301, an NMS communicat ion uni t 302, a database
uni t 303, and an execut ion uni t 304.
[0032]
The radio communicat ion processing uni t 300 communicates to a
10 mobi le terminal , for example, a radio terminal .
[0033]
The inter-eNB message processing uni t 301 t ransmi ts and receives
informat ion (hereinafter, referred to as handover informat ion) necessary to
handover a cel l where a mobi le terminal is located.
15 [0034]
The NMS communicat ion uni t 302 communicates to the NMS 201
via an inter face communicable to the NMS 201. In the present exemplary
embodiment , the NMS communicat ion uni t 302 receives, f rom the NMS
201, informat ion (hereinafter, referred to as backhaul resource load
20 informat ion) indicat ing a backhaul resource load in a bot t leneck l ink.
The bot t leneck l ink is a l ink having the highest load between an eNB and
an EPC.
[0035]
The database uni t 303 holds backhaul resource load informat ion
25 received by the NMS communicat ion uni t 302. Further, the database uni t
303 holds, as handover informat ion, informat ion on a terminal located in a
cel l of an own stat ion, informat ion on the own stat ion, informat ion on an
adjacent eNB, and the l ike. These pieces of informat ion held by the
database uni t 303 are updated by the inter -eNB message processing uni t
14
301 and the NMS communicat ion uni t 302, as needed.
[0036]
The execut ion uni t 304 executes MLB on the basis of the
informat ion held by the database uni t 303.
[00375 ]
It should be noted that the radio communicat ion processing uni t 300,
the inter-eNB message processing uni t 301, the NMS communicat ion uni t
302, and the execut ion uni t 304 are real ized, for example, using a CPU
(Central Processing Uni t ) of a computer operat ing in accordance wi th a
10 program. The CPU reads a program f rom a storage apparatus (not
i l lust rated) and operates as the radio communicat ion processing uni t 300,
the inter-eNB message processing uni t 301, the NMS communicat ion uni t
302, and the execut ion uni t 304 in accordance wi th the program. Further,
the radio communicat ion processing uni t 300, the inter -eNB message
15 processing uni t 301, the NMS communicat ion uni t 302, and the execut ion
uni t 304 may be real ized using separate pieces of hardware, respect ivel y.
[0038]
Further, the database uni t 303 is real ized usin g a storage apparatus
such as a RAM (Random Access Memory) of a computer, or the l ike.
20 [0039]
Fig. 3 is a block diagram i l lust rat ing a configurat i on of the fi rst
exemplary embodiment of a management control apparatus according to the
present invent ion. As i l lustrated in Fig. 3, the management cont rol
apparatus (NMS 201) includes a relay apparatus communicat ion uni t 310, a
25 load informat ion operat ion uni t 311, an eNB communicat ion uni t 312, and
a database uni t 313.
[0040]
The relay apparatus communicat ion uni t 310 receives backhaul
resource load informat ion for each l ink f rom respect ive relay apparatuses
15
connected to an own apparatus. As one example of a uni t of a value
indicated by the backhaul resource load informat ion, a bi t rate (bps) or the
number of t ransfer red bytes (MB, GB) per uni t t ime is ci ted.
[0041]
The load informat ion operat ion uni t 311 normal izes the backhau5 l
resource load informat ion of each l ink to percentage of a phys ical speed of
the l ink. The load informat ion operat ion uni t 311 extracts a l ink having
the highest load, i .e. a bot t leneck l ink between an eNB and the EPC 240 for
each eNB on the basis of the normal ized backhaul resou rce load
10 informat ion.
[0042]
The eNB communicat ion uni t 312 t ransmi ts backhaul resource load
informat ion of the bot t leneck l ink extracted for each eNB to a
corresponding eNB. At that t ime, the eNB communicat ion uni t 312
15 transmi ts a value indicated by the backhaul resource load informat ion of
the bot t leneck l ink to the eNBs 211 to 213 via mapping to (associat ion
wi t h ) a n i n d ex o f a n y o n e o f f o u r s t a g es ( “ Low Lo ad , ” “Med i umLo ad , ”
"Hi g h Lo ad , ” an d “Ov e r l o ad ” ) , i n t h e simi lar manner as for S1 network load
informat ion.
20 [0043]
Fig. 4 is an i l lust rat ive diagram i l lustrat ing one example of
informat ion represent ing a conversion algorism to convert backhaul
resource load informat ion to S1 network load informat ion. It should be
noted that informat ion represent ing the conversion algorism i l lust rated in
25 Fig. 4 is stored in advance on a storage uni t (not i l lust rated) included in the
NMS 201. In the example i l lustrated in Fig. 4, when a value indicated by
backhaul resource load informat ion is equal to or greater than 70%, the
v al u e i s as s o ci a t e d t o b e co n v er t ed t o “Ov e r l o ad . ” Fu r t h er, wh en a v a l u e
indicated by backhaul resource load informat ion is equal to or greater than
16
50% and smal ler than 70%, the value is associated to be converted to
“Hi g h Lo a d . ” F u r t h er, wh en a v a lue indicated by backhaul resource load
informat ion is equal to or greater than 20% and smal ler than 50%, the
v al u e i s as s o ci at e d t o b e co n v er t ed t o “Med i umLo a d . ” Fu r t h e r, wh en a
value indicated by backhaul resource load informat ion is equal to o5 r
greater than 0% and smal ler than 20%, the value is associated to be
co n v e r t ed t o “ Low Lo ad . ”
[0044]
The database uni t 313 holds backhaul resource load informat ion of
10 respect ive l inks between an eNB and an EPC and mapping informat ion of
the eNB and the EPC for the respect ive l inks. These pieces of
informat ion held by the database uni t 313 are updated by the relay
apparatus communicat ion uni t 310 and the eNB communicat ion uni t 312, as
needed.
15 [0045]
It should be noted that the relay apparatus communicat ion uni t 31 0,
the load informat ion operat ion uni t 311, and the eNB communicat ion uni t
312 are real ized, for example, using a CPU of a computer operat ing in
accordance wi th a program. The CPU reads a program from a storage
20 apparatus (not i l lustrated) and operates as the relay apparatus
communicat ion uni t 310, the load informat ion operat ion uni t 311, and the
eNB communicat ion uni t 312 in accordance wi th the program. Further,
the relay apparatus communicat ion uni t 310, the load informat ion
operat ion uni t 311, and the eNB communicat ion uni t 312 may be real ized
25 using separate pieces of hardware, respect ivel y.
[0046]
Further, the database uni t 313 is real ized usin g a storage apparatus
such as a RAM (Random Access Memory) of a computer, or the l ike.
[0047]
17
Next , operat ions of respect ive uni ts in the present exemplary
embodiment wi l l be described.
[0048]
Fig. 5 is a flowchart i l lustrat ing operat ions from col lect ing
backhaul resource load informat ion of respect ive l inks for an eNB t5 o
extract ing a bot t leneck l ink using the NMS 201.
[0049]
The relay apparatus communicat ion uni t 310 of the NMS 201
col lects pieces of backhaul resource load informat ion of respect ive l inks
10 for an eNB (step S001). The relay apparatus communicat ion uni t 310
col lects, when col lect ing, for example, pieces of backhaul resource load
informat ion of respect ive l ink for the eNB 211, pieces of backhaul resource
load informat ion of a l ink 231, a l ink 232, a l ink 233, a l ink 234, and a l ink
235.
15 [0050]
The load informat ion operat ion uni t 311 normal izes the pieces of
backhaul resource load informat ion of the resp ect ive l inks to percentage of
physical speeds of the l inks (step S002). Fig. 6 is an i l lustrat ive diagram
i l lust rat ing one example of backhaul resource load informat ion of
20 respect ive l inks between the eNB 211 and an EPC. Fig. 6 i l lustrates
backhaul resource load informat ion normal ized to percentage.
[0051]
The load informat ion operat ion uni t 311 determines, as a bot t leneck
l ink, a l ink in which a value indicated by the normal ized backhaul resource
25 load informat ion is the largest (step S003). At that t ime, the load
informat ion operat ion uni t 311 may extract , as a bot t leneck l ink, a l ink
having the highest load ( the largest value indicated by backhaul resource
load informat ion) among l inks f rom an eNB to an Nth-hop, instead of al l
l inks between the eNB and the EPC.
18
[0052]
The load informat ion operat ion uni t 311 may ext ract , as a
bot t leneck l ink, a l ink having the highest load, for example, among l inks
from an eNB to SeGW (Securi ty Gateway) that is an ent rance of an
operator network or, for example, among l inks from an eNB to a thin l in5 k
that is a l ink l ikely to be relat ively congested in a backhaul network.
Herein, the load informat ion operat ion uni t 311 extracts a l ink having the
highest load among l inks (the l inks 231 to 233) in an access area and an
aggregat ion area. As i l lust rated in Fig. 6, a l ink having the highest load
10 among the l inks (the l inks 231 to 233) in the access area and the
aggregat ion area is the l ink 233 in which a value indicated b y backhaul
r e s o u r ce l o ad i n f o rmat i o n i s “ 55%. ”
[0053]
The eNB communicat ion uni t 312 associates the value indicated by
15 the backhaul resource load informat ion of the l ink 233 wi th the same index
as for S1 network load informat ion in accordance wi th informa t ion
represent ing the conversion algorism exempl ified in Fig. 4. Specif ical l y,
t h e eNB commu n i c at i o n u n i t 3 1 2 c o n v e r t s t h e v al u e “ 55%” i n d i c at e d b y t h e
b a ck h a u l r es o u r c e l o ad i n f o rmat i o n o f t h e l i n k 2 3 3 t o “Hi gh Lo ad . ” Then,
20 the eNB communicat ion uni t 312 t ransmi ts the backhaul resource load
informat ion after the conversion to the eNB 211.
[0054]
Fig. 7 is a sequence diagram i l lustrat ing an operat ion for
transmi t t ing the backhaul resource load informat ion after the conversion to
25 the eNB 211 using the NMS 201.
[0055]
As i l lust rated in Fig. 7, the NMS 201, speci fical l y, the eNB
communicat ion uni t 312 transmi ts backhaul resource load informat ion of a
bot t leneck l ink to the eNB 211. Herein, the eNB communicat ion uni t 312
19
t r a n smi t s “Hi gh Lo a d ” t o t h e eNB 2 11 a s the backhaul resource load
informat ion of the bot t leneck l ink (step S011).
[0056]
Upon receiving the backhaul resource load informat ion of the
bot t leneck l ink, the eNB 211, speci fical ly, the NMS communicat ion uni 5 t
302 stores the received backhaul resour ce load informat ion on the database
uni t 303. Further, the NMS communicat ion uni t 302 t ransmi ts a resource
status update message including S1 network load informat ion set wi th
“Hi g h Lo a d ” t o an a d j a c en t eNB ( e. g . t h e eNB 2 1 2 i l l u s t r at e d i n Fi g. 1 ) .
10 It should be noted that i t may be configured the inter-eNB message
processing uni t 301 t ransmi t s the resource status update message including
S 1 n etwo r k l o a d i n f o rma t i o n s et wi t h “Hi g h Lo ad ” t o a n ad j a ce n t eNB ( e. g .
the eNB 212 i l lustrated in Fig. 1) .
[0057]
15 In the simi lar manner, the eNB 212 receives the backhaul resource
load informat ion of the bot t leneck l ink transmi t ted f rom the NMS 201.
When receiving, for example, backhaul resource load informat ion
i n d i cat i n g “ LowLo a d , ” t h e eNB 2 1 2 t r an smi t s a r es o u r c e s t a tus update
mes s a g e i n cl u d i n g S 1 n e two r k l o ad i n f o rmat i o n s et wi t h “ LowLo ad ” t o a n
20 adjacent eNB (e.g. the eNB 211).
[0058]
Upon receiving a resource status update message f rom the adjacent
eNB, the inter-eNB message processing uni t 301 of each eNB stores
backhaul resource load informat ion included in the message on the
25 database uni t 303. Then, the execut ion uni t 304 of each eNB executes
MLB on the basis of the informat ion held by the database uni t 303.
[0059]
In this manner, when the inter -eNB message processing uni t 301 of
each eNB t ransmi ts a resource status update message, eNBs can share
20
backhaul resource load informat ion of a bot t leneck l ink between each eNB
and the EPC 240. Therefore, this enables the execut ion uni t 304 of each
eNB to designate a cel l of an adjacent eNB having a lower t raffic load of a
bot t leneck l ink as a handover dest inat ion. In other words, i t is possible
to execute MLB considering a backhaul resource load of a l ink locate5 d
ahead of an access l ink.
[0060]
As described above, in the present exemplary embodiment , an NMS
col lects backhaul resource load informat ion of respect ive l inks f rom an
10 eNB to an EPC. Then, a bot t leneck l ink is extracted on the basis of the
col lected backhaul resource load informat ion of the respect ive l inks an d
backhaul resource load informat ion of the extracted bot t leneck l ink is
transmi t ted to eNBs. Thereby, the eNBs can accurately acquire backhaul
resource load informat ion of a l ink having the highest load (bot t leneck
15 l ink) in an access link and an aggregat ion l ink.
[0061]
Further, in the present exemplary embodiment , each eNB reports
backhaul resource load informat ion of a bot t leneck l ink between an own
stat ion and an EPC received f rom an NMS to an adjacent eNB on the basis
20 of a resource status update mess age. Thereby, each eNB can acquire
backhaul resource load informat ion of a bot t leneck l ink between the
adjacent eNB and an EPC. Therefore, i t is possible to cause Handover
between eNBs in MLB to succeed more certainly. Therefore, i t is
possible to avoid backhaul congest ion of an access l ink and an aggregat ion
25 l ink and a throughput decrease of a radio terminal . In other words, MLB
can be executed by considering a congest ion status of a backhaul .
[0062]
Further, in the present exemplary embodiment , a loa d informat ion
operat ion uni t of an NMS may be configured to extract , as a bot t leneck l ink,
21
a l ink having the highest load among l inks from an eNB to an Nth-hop,
instead of l inks f rom the eNB to an EPC. Such a configurat ion makes i t
possible to extract a bot t leneck l ink in a necessary range to avoid backhaul
congest ion and a throughput decrease of a radio terminal and reduce a load
of extract ion processing of the bot t leneck l ink in the NMS5 .
[0063]
It should be noted that the present exemplary embodiment has been
described, as an example, in which the eNB communicat ion uni t 312 of the
NMS 201 converts backhaul resource load informat ion of a bot t leneck l ink
10 to the same index as for S1 network load informat ion, but each eNB may
execute this conversion. To real ize such a form, the eNB communicat ion
uni t 312 may t ransmi t backhaul resource load informat ion of a bot t leneck
l ink normal ized to percentage to each eNB. Then, each eNB (e.g. the
NMS communicat ion uni t 302 of each eNB) may convert the backhaul
15 resource load informat ion normal ized to the percentage to an index of any
one of the same four stages as for S1 network load informat ion and store
the resul t ing index on the database uni t 303. In this case, informat ion
represent ing the conversion algorism exempl i f ied in Fig. 4 is stored in
advance on a storage uni t (not i l lust rated) included in each eNB.
20 [0064]
Further, the eNB communicat ion uni t 312 of the NMS 201 may
transmi t backhaul resource load informat ion of a bot t leneck l ink to cont rol
apparatuses (SON (Self Organizing Network)/EMS (Element Management
System)/HeNB-GW (Home eNB-Gateway) ) that manage eNBs.
25 [0065]
Further, the relay apparatus communicat ion uni t 310 of the NMS
201 may acquire backhaul resource load informat ion of respect ive l inks
from an eNB to an Nth-hop, instead of acqui ring backhaul resource load
informat ion of al l l inks between the eNB to an EPC. Then, the load
22
informat ion operat ion uni t 311 may ext ract a bot t leneck l ink from the
respect ive l inks f rom the eNB to the Nth-hop and the eNB communicat ion
uni t 312 transmi ts backhaul resource load informat ion of the bot t leneck
l ink to eNBs. In this manner, when backhaul resource load informat ion is
acqui red in a range necessary to avoid backhaul congest ion and 5 a
throughput decrease of a radio terminal , a processing load of the NMS 201
can be reduced.
[0066]
Second Exemplary Embodiment
10 A second exemplary embodiment of the present invent ion wi l l be
described wi th reference to the drawings .
[0067]
A configurat ion of a communicat ion system in the se cond
exemplary embodiment is the same as the configurat ion of the first
15 exemplary embodiment i l lustrated in Fig. 1.
[0068]
However, the eNB communicat ion uni t 312 of the NMS 201 of the
present exemplary embodiment transmi ts pieces of backhaul resource load
informat ion of respect ive l inks in a backhaul between each eNB and an
20 EPC 240 and physical speeds of the respect ive l inks to eNBs. Then, each
eNB normal izes the pieces of backhaul resource load informat ion of the
respect ive l inks to percentage of the physical speeds of the l inks .
[0069]
Fig. 8 is a block diagram i l lust rat ing a configurat ion of the second
25 exemplary embodiment of a radio base stat ion according to the present
invent ion. As i l lustrated in Fig. 8, each eNB includes a n operat ion uni t
305 in addi t ion to the configurat ion of the fi rst exemplary embodiment
i l lust rated in Fig. 2.
[0070]
23
The NMS communicat ion uni t 302 of each eNB receives pieces of
backhaul resource load informat ion of respect ive l inks in a backhaul
between an own stat ion and the EPC 240 and physical speeds of the
respect ive l inks. Then, the operat ion uni t 305 normal izes values
indicated by the pieces of backhaul resource load informat ion of th5 e
respect ive l inks to percentage of the phys ical values of the respect ive l inks.
Further, the operat ion uni t 305 ext racts a bot t leneck l ink between an own
stat ion and the EPC 240 on the basis of values indicated by the normal ized
pieces of backhaul resource load informat ion of the respect ive l inks and
10 stores backhaul resource load informat ion of the ext racted bot t leneck l ink
on the database uni t 303.
[0071]
It should be noted that the radio communicat ion processing uni t 300,
the inter-eNB message processing uni t 301, the NMS communicat ion unit
15 302, the execut ion uni t 304, and the operat ion uni t 305 are real ized, for
example, using a CPU of a computer operat ing in accordance wi th a traff ic
load distribut ion program. The t raffic load dist ribut ion program is stored ,
for example, on a storage apparatus (not i l lustrated) of the computer. The
CPU reads the program and operates as the radio communicat ion
20 processing uni t 300, the inter -eNB message processing uni t 301, the NMS
communicat ion uni t 302, the execut ion uni t 304, and the operat ion uni t 305
in accordance wi th the program. Further, the radio communicat ion
processing uni t 300, the inter -eNB message processing uni t 301, the NMS
communicat ion uni t 302, the execut ion uni t 304, and the operat ion uni t 305
25 may be real ized using separate pieces of hardware.
[0072]
In this manner, in the present ex emplary embodiment , the operat ion
uni t 305 of each eNB normal izes values indicated by pieces of backhaul
resource load informat ion of respect ive l inks and extracts a bot t leneck l ink.
24
Therefore, i t is only necessary for the NMS 201 to transmi t pieces of
backhaul resource load informat ion of respect ive l inks and physical speeds
of the respect ive l inks to eNBs. Therefore, a general -purpose
management apparatus that manages l inks between eNBs and a mobi le core
network becomes usable as the NMS 2015 .
[0073]
Thi rd Exemplary Embodiment
A thi rd exemplary embodiment of the present invent ion wi l l be
described wi th reference to the drawings.
10 [0074]
A configurat ion of a communicat ion system in the third exemplary
embodiment is the same as in the f irst exemplary embod iment .
[0075]
However, the eNB communicat ion uni t 312 of the NMS 201 of the
15 present exemplary embodiment t ransmi ts , to eNBs, backhaul resource load
informat ion of respect ive l inks between an eNB and an EPC and backhaul
resource load informat ion of a l ink f rom the eNB to a first -hop, in addi t ion
to backhaul resource load informat ion of a bot t leneck l ink.
[0076]
20 Further, the inter-eNB message processing uni t 301 of each eNB
d es i g n at es b a ck h a u l r es o u r c e l o a d i n f o rmat i o n ( “S 1 TN L Lo ad ” ) o f
respect ive l inks between an eNB and an EPC, backhaul resource load
i n f o rmat i o n ( “ 1 Ho p Li n k S 1 TN L Lo ad ”) of a l ink from an eNB to a
first - h o p , a n d b a ck h au l r e s o u r ce l o a d i n f o rma t i o n ( “ Bo t t l en e ck Li n k S 1
25 TN L Lo a d ” ) o f a b o t t l en e ck l i n k as ad d i t i v e IE s ( In f o rma t i o n E l emen t s ) of
a resource status update message between X2 l inks. Fig. 9 is an
i l lust rat ive diagram i l lust rat ing one example of a st ructure of a resource
status request message designated wi th addi t ive IEs.
[0077]
25
In this manner, in the present exemplary embodiment , each eNB
receives, f rom an NMS, backhaul resource load informat ion of respect ive
l inks between an eNB and an EPC and backhaul resource load informat ion
of a l ink f rom the eNB to a first -hop, in addi t ion to backhaul resource load
informat ion of a bot t leneck l ink. This enables an eNB to acquire mor5 e
accurate backhaul resource load informat ion f rom the NMS. Further, in
the present exemplary embodiment , eNBs share informat ion received by
each eNB f rom the NMS. This enables each eNB to acquire more
accurately backhaul resource load informat ion of l inks between an adjacent
10 eNB and the EPC.
[0078]
It should be noted that the eNB communicat ion uni t 312 of the NMS
201 may t ransmi t , to an eNB, backhaul resource load informat ion of
respect ive l inks between the eNB and the EPC and respect ive l inks
15 between an eNB adjacent to the eNB and the EPC.
[0079]
Further, the eNB communicat ion uni t 312 may extract a bot t leneck
l ink f rom respect ive l inks from an eNB to an Nth -hop. Then, i t is
possible to t ransmi t backhaul resource load informat ion of the bot t leneck
20 l ink to eNBs, together wi th backhaul resource load informat ion of the
respect ive l inks between the eNB to the Nth-hop and backhaul resource
load informat ion of a l ink f rom the eNB to a fi rst -hop.
[0080]
Whi le the invent ion has been part icularly shown and described wi th
25 reference to exemplary embodiments thereof, the invent ion is not l imi ted
to these embodiments. It wi l l be understood by those of ordinary ski l l in
the art that various changes in form and detai ls may be made therein
wi thout depar t ing from the spi ri t and scope of the present invent ion as
defined by the claims.
26
[0081]
Next , a summary of the present invent ion wi l l be described.
[0082]
Fig. 10 is a block diagram i l lust rat ing a minimal configurat ion of
the communicat ion system according to the present invent ion. A5 s
i l lust rated in Fig. 10, the communicat ion system according to the present
invent ion includes radio base stat ions 10 -1 to 10-n (equivalent to the eNBs
211 to 213 i l lustrated in Fig. 1) and a man agement control apparatus 20
(equivalent to the NMS 201 i l lust rated in Fig. 1); the management cont rol
10 apparatus 20 includes a fi rst communicat ion uni t 21 (equivalent to the
relay apparatus communicat ion uni t 310 i l lust rated in Fig. 3) that col lects
backhaul resource load informat ion indicat ing traff ic loads of respect ive
l inks in backhauls between the radio base stat ions 10 -1 to 10-n and a core
network f rom relay apparatuses (equivalent to the relay apparatuses 221 to
15 226 i l lust rated in Fig. 1) that relay communicat ions between the radio base
stat ions 10-1 to 10-n and the core network, an operat ion uni t 22 (equivalent
to the load informat ion operat ion uni t 311 i l lust rated in Fig. 3) that
extracts, for each radio base stat ion, a bot t leneck l ink having the highest
load among respect ive l inks in a backhaul between a radio base stat ion and
20 the core network on the basis of the backhaul resource load informat ion
col lected by the first communicat ion uni t 21, and a second communicat ion
uni t 23 (equivalent to the eNB communicat ion uni t 312 i l lust rated in Fig.
3) that t ransmi ts backhaul resource load informat ion of the bot t leneck l ink
to the radio base stat ions 10-1 to 10-n; and the radio base stat ions 10 -1 to
25 10-n each include an execut ion uni t 11 (equivalent to the e xecut ion uni t
304 and, i l lust rated in Fig. 2) that executes dist ribut ion of the traffic loads
among the radio base stat ions on the basis of the backhaul resource load
informat ion of the bot t leneck l ink in a backhaul between an own base
stat ion and the core network received f rom the management cont rol uni t
27
20.
[0083]
Such a conf igurat ion enables a radio base stat ion to accurately
acqui res backhaul resource load informat ion of a l ink (bot t leneck l ink)
having the highest load in an access l ink and an aggregat ion l ink5 .
Therefore, MLB can be executed by considering a congest ion status of a
backhaul .
[0084]
Further, the operat ion uni t 22 may normal ize a value indicated by
10 backhaul resource load informat ion of each l ink to a percentage of a
physical speed of the each l ink. Such a configurat ion makes i t possible to
apply the present invent ion also to a radio communicat ion network in
which physical speeds of respect ive l inks are di fferent from each other.
[0085]
15 Further, the operat ion uni t 22 may extract a bot t leneck l ink on the
basis of normal ized backhaul resource load informat ion of respect ive l inks.
Such a configurat ion makes i t possible to accurately extract a bot t leneck
l ink even when phys ical speeds of the respect ive l inks are di fferent from
each other.
20 [0086]
Further, the radio base stat ions 10 -1 to 10-n each may include a
message processing uni t 12 (equivalent to the inter-eNB message
processing uni t 301 i l lust rated in Fig. 2) that transmi ts backhaul resource
load informat ion of a bot t leneck l ink in a backhaul between an own stat ion
25 and a core network received f rom the management control apparatus 20 to
an adjacent radio base stat ion. Such a configurat ion enables the radio
base stat ions to share the backhaul resource load informat ion of the
bot t leneck l ink. Therefore, t raffic loads among the radio base stat ions
can be dist ributed more certainly.
28
[0087]
Further, the operat ion uni t 22 may ext ract a l ink having the highest
load among respect ive l inks from a radio base stat ion to an Nth -hop as a
bot t leneck l ink. According to such a configurat ion, since a bot t leneck
l ink is extracted in a necessary range to avoid backhaul congest ion and 5 a
throughput decrease of a radio terminal , a load of extract ion processing of
a bot t leneck l ink in a management cont rol app aratus can be reduced.
[0088]
Further, the execut ion uni t 11 may execute Handover on the basis of
10 backhaul resource load informat ion of a bot t lene ck l ink in a backhaul
between an own stat ion and a core network and backhaul resource load
informat ion of a bot t leneck l ink, received by the message processing uni t
12 f rom an adjacent radio base stat ion, in a backhaul between the adjacent
radio base stat ion and the core network. Wi th such a configurat ion,
15 Handover between radio base stat ions based on MLB can be successful ly
performed more certainl y. Therefore, backhaul congest ion of an access
l ink and an aggregat ion l ink and a throughput decrease of a radio terminal
can be avoided more certainl y.
[0089]
20 Fig. 11 is a block diagram i l lust rat ing a minimal conf igu rat ion of
the radio base stat ion according to the present invent ion. As i l lustrated
in Fig. 11, the radio base stat ion according to the present invent ion
includes: a communicat ion uni t 13 (equivalent to the NMS communicat ion
uni t 302 i l lust rated in Fig. 8) that receives backhaul resource load
25 informat ion of respect ive l inks in a backhaul between an own stat ion and a
core network from the management control apparatus 20 that manages
communicat ion resources in a backhaul between radio base stat ions and the
core network; an operat ion uni t 14 (equivalent to the operat ion uni t 305
i l lust rated in Fig. 8) that extracts a bot t leneck l ink having the highest load
29
among the respect ive l inks in the backhaul between an own stat ion and the
core network on the basis of the backhaul resource load informat ion
received f rom the management cont rol apparatus 20; and an execut ion uni t
11 that executes dist ribut ion of t raffic loads among the radio base stat ions
on the basis of backhaul resource load informat ion of the bot t leneck l ink5 .
[0090]
The whole or part of the exemplary embodiments disclosed above
can be described as, but not l imi ted to, the fol lowing supplementary notes .
[0091]
10 (Supplementary note 1) A communicat ion system comprising radio
base stat ions and a management cont rol apparatus, wherein
the management cont rol apparatus includ es:
a fi rst communicat ion means for col lect ing backhaul resource load
informat ion indicat ing traffic loads of respect ive l inks in a backhaul
15 between the radio base stat ions and a core netwo rk from relay apparatuses
that relay communicat ions between the radio base stat ions and the core
network;
an operat ion means for extract ing, for each radio base stat ion, a
bot t leneck l ink having the highest load among respect ive l inks in a
20 backhaul between a radio base stat ion and the core network on the basis of
the backhaul resource load informat ion col lected by the fi rst
communicat ion means; and
a second communicat ion means for transmi t t ing backhaul resource
load informat ion of the bot t leneck l ink to t he radio base stat ions, and
25 the radio base stat ion includes
an execut ion means for execut ing dist ribut ion of traff ic loads
among the radio base stat ions on the basis of backhaul resource load
informat ion of a bot t leneck l ink in a backhaul between an own stat ion and
the core network received f rom the management cont rol apparatus.
30
[0092]
(Supplementary note 2) The communicat ion system according to
Supplementary note 1, wherein
the operat ion means normal izes pieces of backhaul resource load
informat ion of respect ive l inks to percentage of physical speeds of th5 e
respect ive l inks.
[0093]
(Supplementary note 3) The communicat ion system according to
Supplementary note 2, wherein
10 the operat ion means extracts a bot t leneck l ink on the basis of the
normal ized pieces of backhaul resource load informat ion of the respect ive
l inks.
[0094]
(Supplementary note 4) The communicat ion system according to
15 any one of Supplementary note 1 to Supplementary note 3, wherein
the radio base stat ion comprises a message processing means for
transmi t t ing backhaul resource load informat ion of a bot t leneck l ink in a
backhaul between an own stat ion and a core network to an adjacent radio
base stat ion, the informat ion being received f rom the management cont rol
20 apparatus.
[0095]
(Supplementary note 5) The communicat ion system according to
Supplementary note 4, wherein
the execut ion means executes handover on the basis of backhaul
25 resource load informat ion of a bot t leneck l ink in a backhaul between an
own stat ion and a core network and ba ckhaul resource load informat ion of
a bot t leneck l ink, received by the message processing means f rom an
adjacent radio base stat ion, in a backhaul between the adjacent radio base
stat ion and the core network.
31
[0096]
(Supplementary note 6) The communicat ion system according to
any one of Supplementary note 1 to Supplementary note 5, wherein the
operat ion means t ransmi ts, to the radio base stat ion, backhaul resource
load informat ion of a bot t leneck l ink associated wi t h an i n d e x o f “S 1 TN5 L
Lo a d ” i n a RE S OUR CE STATUS UPDATE message specif ied in technical
speci ficat ions (TS 36.423 Version 11.5.0).
[0097]
(Supplementary note 7) The communicat ion system according to
10 any one of Supplementary note 1 to Supplementary Note 6, wherein the
operat ion means ext racts, as a bot t leneck l ink, a l ink having the highest
load among respect ive l inks f rom the radio base stat ion to an Nth -hop.
[0098]
(Supplementary note 8) The communicat ion system according to
15 any one of Supplementary note 1 to Supplementary note 6, wherein the
second communicat ion means of the management cont rol apparatus
transmi ts, to the radio base stat ion together wi th backhaul resource load
informat ion of a bot t leneck l ink between the radio base stat ion and a core
network, backhaul resource load informat ion of respect ive l inks between
20 the radio base stat ion and the core network and backhaul resource load
informat ion of a l ink from the radio base stat ion to a first -hop; and the
execut ion means of the radio base stat ion transmi ts, to an adjacent radio
base stat ion, backhaul resource load informat ion of a bot t leneck l ink
between an own stat ion and the core network, backhaul resource load
25 informat ion of respect ive l inks between an own stat ion and the core
network, and backhaul resource load informat ion of a l ink f rom the own
stat ion to a fi rst -hop received from the management cont rol apparatus.
[0099]
(Supplementary note 9) A radio base stat ion comprising:
32
a communicat ion means for receiving, f rom a management control
apparatus that manages communicat ion resources i n a backhaul between
radio base stat ions and a core network, backhaul resource load informat ion
of respect ive l inks in a backhaul between an own stat ion and the core
network5 ;
an operat ion means for extract ing a bot t leneck l ink having the
highest load among respect ive l inks in a backhaul between an own stat ion
and the core network on the basis of the backhaul resource load
informat ion received f rom the management cont rol apparatus; and
10 an execut ion means for execut ing dist ribut ion of traff ic loads
among the radio base stat ions on the basis of backhaul resource load
informat ion of the bot t leneck l ink.
[0100]
(Supplementary note 10) The radio base stat ion according to
15 Supplementary note 9, wherein the communicat ion means receives,
together wi th pieces of backhaul resource load informat ion of respect ive
l inks in a backhaul between an own stat ion and the core network, pieces of
informat ion indicat ing physical speeds of the respect ive l inks f rom the
management cont rol apparatus ; and the operat ion means normal izes the
20 pieces of backhaul resource load informat ion of the respect ive l inks to
percentage of the physical speeds of the respect ive l inks on the basis of
pieces of informat ion indicat ing the physical speeds of the respect ive
l inks.
[0101]
25 (Supplementary note 11) The radio base stat ion according to
Supplementary note 10, wherein
the operat ion means extracts a bot t leneck l ink on the basis of the
normal ized pieces of backhaul resource load informat ion of the respect ive
l inks.
33
[0102]
(Supplementary note 12) The radio base stat ion according to any
one of Supplementary note 9 to Supplementary note 11, including
a message processing means for transmi t t ing backhaul
resource load informat ion of a bot t leneck l ink in a backhaul between a5 n
own stat ion and a core network to an adjacent radio base stat ion.
[0103]
(Supplementary note 13) The radio base stat ion according to
Supplementary note 12, wherein
10 the execut ion means executes handover on the basis of backhaul
resource load informat ion of a bot t leneck l ink in a backh aul between an
own stat ion and a core network and backhaul resource load informat ion of
a bot t leneck l ink, received by the message processing means f rom an
adjacent radio base stat ion, in a backhaul between the adjacent radio base
15 stat ion and the core network.
[0104]
(Supplementary note 14) The radio base stat ion according to any
one of Supplementary note 9 to Supplementary note 12, wherein the
operat ion means ext racts, as a bot t leneck l ink, a l ink having the highest
20 load among respect ive l inks f rom a radio base stat ion to an Nth-hop radio
base stat ion.
[0105]
This appl icat ion is based upon and claims the benefi t of pr iori ty
from Japanese patent appl icat ion No. 2013-222923, fi led on October 28,
25 2013, the disclosure of which is incorporated herein in i ts e nt i rety by
reference.
[Reference signs List]
[0106]
10-1 to 10-n Radio base stat ion
34
11 Execut ion uni t
12 Message processing uni t
13 Communicat ion uni t
14 Operat ion uni t
20 Management control apparatu5 s
21 Fi rst communicat ion uni t
22 Operat ion uni t
23 Second communicat ion uni t
100, 240 EPC
10 101, 102, 221 to 226 Relay apparatus
103 to 105, 211 to 213 eNB
106 Radio terminal
107, 108, 109 Cel l
111 to 115, 231 to 235 Link
15 201 NMS
300 Radio communicat ion processing uni t
301 Inter-eNB message processing uni t
302 NMS communicat ion uni t
303 Database uni t
20 304 Execut ion uni t
305 Operat ion uni t
310 Relay apparatus communicat ion uni t
311 Load informat ion operat ion uni t
312 eNB communicat ion uni t
25 313 Database uni t
35

[Document Name] CLAIMS
[Claim 1]
A communicat ion system compr ising radio base stat ions and a
management cont rol apparatus, wherein
the management cont rol apparatus includ 5 es:
a fi rst communicat ion means for col lect ing backhaul resource load
informat ion indicat ing traffic loads of respect ive l inks in a backhaul
between the radio base stat ions and a core network from relay apparatuses
that relay communicat ions between the radio base stat ions and the core
10 network;
an operat ion means for extract ing, for each radio base stat ion, a
bot t leneck l ink having the highest load among respect ive l inks in a
backhaul between a radio base stat ion and the core network on the basis of
the backhaul resource load informat ion col lected by the fi rst
15 communicat ion means; and
a second communicat ion means for transmi t t ing backhaul resource
load informat ion of the bot t leneck l ink to the radio base stat ion s, and
the radio base stat ion includes
an execut ion means for execut ing dist ribut ion of traff ic loads
20 among the radio base stat ions on the basis of backhaul resource load
informat ion of a bot t leneck l ink in a backhaul between an own stat ion and
the core network received f rom the management cont rol apparatus.
[Claim 2]
The communicat ion system according to Claim 1, wherein
25 the operat ion means normal izes pieces of backhaul resource load
informat ion of respect ive l inks to percentage of physical speeds of the
respect ive l inks.
[Claim 3]
The communicat ion system according to Claim 2, wherein
36
the operat ion means extracts a bot t leneck l ink on the basis of the
normal ized pieces of backhaul resource load informat ion of the respect ive
l inks.
[Claim 4]
The communicat ion system according to any one of Claim 1 t5 o
Claim 3, wherein
the operat ion means extracts, as a bot t leneck l ink, a l ink having the
highest load among respect ive l inks f rom the radio base stat ion to an
Nth-hop.
10 [Claim 5]
The communicat ion system according to any one of Claim 1 to
Claim 4, wherein
the radio base stat ion comprises a message processing means for
transmi t t ing backhaul resource load informat ion of a bot t leneck l ink in a
15 backhaul between an own stat ion and a core network to an adjacent radio
base stat ion, the informat ion being received f rom the management cont rol
apparatus .
[Claim 6]
The communicat ion system according t o Claim 5, wherein
20 the execut ion means executes handover on the basis of backhaul
resource load informat ion of a bot t leneck l ink in a backhaul between an
own stat ion and a core network and backhaul resource load informat ion of
a bot t leneck l ink, received by the message processing means f rom an
adjacent radio base stat ion, in a backhaul between the adjacent radio base
25 stat ion and the core network.
[Claim 7]
A radio base stat ion comprising:
a communicat ion means for receiving, f rom a management control
apparatus that manages communicat ion resources in a backhaul between
37
radio base stat ions and a core network, backhaul resource load informat ion
of respect ive l inks in a backhaul between an own stat ion and the core
network;
an operat ion means for extract ing a bot t leneck l ink having the
highest load among respect ive l inks in a backhaul between an own stat io5 n
and the core network on the basis of the backhaul resource load
informat ion received f rom the management cont rol apparatus; and
an execut ion means for execut ing dist ribut ion of traff ic loads
among the radio base stat ions on the basis of backhaul resource load
10 informat ion of the bot t leneck l ink.
[Claim 8]
A t raffic load dist ribut ion method comprising:
receiving, f rom a management cont rol apparatus that man ages
communicat ion resources in a backhaul between radio base stat ions and a
15 core network, backhaul resource load informat ion of respect ive l inks in a
backhaul between an own stat ion and the core network;
extract ing a bot t leneck l ink having the highest load among
respect ive l inks in a backhaul between an own stat ion and the core network
on the basis of the backhaul resource load informat ion received from the
20 management cont rol apparatus; and
execut ing dist ribut ion of t raffic loads among the radio base sta t ions
on the basis of backhaul resource load informat ion of the bot t leneck l ink.
[Claim 9]
A storage medium storing a t raffic load distr ibut ion program that
25 causes a computer to execute:
processing for receiving, from a management cont rol apparatus that
manages communicat ion resources in a backhaul between radio base
stat ions and a core network, backhaul resource load informat ion of
respect ive l inks in a backhaul between an own stat ion and the core
38
network;
processing for extract ing a bot t leneck l ink hav ing the highest load
among respect ive l inks in a backhaul between an own stat ion and the core
network on the basis of the backhaul resource load informat ion received
from the management cont rol apparatus; an5 d
processing for execut ing distribut ion of t raff ic loads among the
radio base stat ions on the basis of backhaul resource load informat ion of
the bot t leneck l ink.