SP34d708WO00 1/37
Description
Title of Invention
COMMUNICATION CONTROL DEVICE, COMMUNICATION CONTROL METHOD, BASE STATION, AND COMMUNICATION CONTROL SYSTEM"
Technical Field
[0001]
The present disclosure relates to a communication control device, a 10 communication control method, a base station, and a communication control system,
Background Art
[0002] -
Recently, a high-speed cellular wireless communication scheme such as
15 LTE (Long Term Evolution) and WiMAX has been used practically, which has
significantly improved a communication rate of wireless communication sei-vice
received by mobile users. Moreover, when a fourth-generation cellular wireless
__.T communication scheme such as LTE-A (LTE-Advanced) is introduced, it is expected
", that the communication rate further improves. - : :
20 [0003]
- _ In addition, the number of mobile users is increasing.rapidly, andean
application requiring a high data rate is being used more widely. As a result, the progress of the cellular wireless communication scheme has not satisfied all needs of mobile users. Thus, the introduction of small cells is promoted in order to
25 complement macro cells and increase communication capacity. Tlie small cell is a
~_^_ concept including a"femtocelL a nanoccll, apicoccil. and a micro cell, forjcxample. _
r~: Thcsmall cell is typicaLJy introduced by arrangingji base station (also referred to as
- " ran access point) smaller than a base station of a nuicro cell (eNH (evolved Node B)
_- ._ ' -in^.Tli^^ror example). However, in an area-wherc a-macro ceil and-a small celi-
'30 ' overlap, "there occurs arisk that radio signals.lransmitted^and received by the small "c"cll will cause interference to terminals connected to the macr6'cell.

S1M44708W()00 2/37
[0004]
In order to avoid the risk of Interfeiencc with introduction of a small cell,
J,Iic following Patent Liteiatiire 1 proposes a method of cooperatively controlling
.transmission po^'er and transmission lates of a macro cell "and a shiall cell. The
following~Patent Liteiatnrc 2 proposcs"a method of cooperatively controlling
transmission beams of a macro and a small cell, - .^,_._^
Citation List
Patent Literature
10 [0005] " "_ '"
Patent Literature 1: - , . JP 2011-211369A
Patent Literature 2; • ' JP 2011-211368A
—'.- Summary of Invention
15 Technical Problem .i
[0006] " . ovv. : , .
However, to achieve cooperative mterference control between a macro cell
and a small cell, high-speed and low-latency signaling between base stations of such
cells is required. For example, to effectively operate the method proposed in Patent
20 Document 1 or 2 described above, it is considered that the latency not exceeding
several radio frames, that is,.several 10 msec is desirable. However, there may be
actually a case in which the above-described desirable communication performance
cannot be obtained for interference control, depending on a form of a small cell or
arrangement of an interference control function.
25"~ [0007f ~~ ~" ~_"~
_ r~ 'Iheiefore, It is dcsiiablc to piovide a m'echanism allowing.j1exibjc_
,switching between interference_controf schemes foj' controlling intcrfcience between.
— a macio cell and a small cell. " . 1 '
30 -Solution to Pi-oblcm ," [0008J

SP344708WO00
3/37
According to the present disclosure, there is provided""a~commiimcation control device including a performance acquisition unit thtit__acquires a parameter
Jndicatingj;^mmunicatipn_p^.rfo on a_signah"ng path-of a base statioii__of a
"..".:_ small reel! that at. least, partially overlaps _wilh a macro _ccll in "a wireless
5 communication system, a selection unit that selects an inteilercncc~control scheme
- -for Gontrolling interference between the macro cell i^rid the STT!?JI cell based on the-
parameter acquired by the performance acquisition-unit, and an interference control
unit that transmits an interference control signal to the base station of the small cell
in accordance with the interference control scheme selected by the selection unit. -
10 [0009]
According to the present disclosure, there is provided a communication
control method including, by a control node in a wireless cotmmmication system,
acquiring a parameter indicating communication performance on a signaling path of
a base station of a small cell that at least partially overlaps with a macro cell,.-
15. selecting an interference control scheme for controlling interference between the
macro cell and the small cell, based on the acquired parameter, and transmitting an
interference control signal to the base station of the small cell in accordance with the
selected interference control scheme, - "-
[0010] .._:..-..
20 According to the present disclosure, there is provided a base station of a
small celLthat. at least. partially overlaps with. a. macro cell in. _a_wirelessl^ communication system, the base station including a communication unit that receives, from a control node controlling interference between the macro cell and the small cell, an interference control signal of an interference control scheme selected based
25 on a parameter indicating coumninicalion performance on a signaling path between
the base station of the sniail cell and a base station of the macro cell, ajid a cotiupher
thai "controls wireless communication bet^^'ccn the base station of the small ceil.and a-tcrminal connected to the small cell in accordance with the interferencc-ControL
,slgnal received by-the communication uiiit.' - - - 1 i_
30 [00.11] ~ -- . " S-^-„ -^ - . '-^' ■"■:_":""
Accoi"ding to the present disclosure, llieic is provided a commuhicatipn

SP344708WOC)0 4/37
eonln)l system including a base station of a small cell that at least partially overlaps --with a macro cell in a wireless communication system, and a control node including
: a pefformance_iicquisition uniLthat acqiiires^pjrameteHndicaJmg.coirLi^^
performanec_on a signaling "path of the base station of the small cell, a selection unit.
_ "5 ^Ihal selects an"interference control scheme for controlling interference between the
macro cell and the small cell, based on the parameter acquired by the performance
—acquisition unit, and an interference control unitlhat transmits an interference control"
signal to the base station of the small cell in accordance with the interference control
-scheme selected by the selection unit.
10
Advantageous Effects of Invention
[0012] """' ^" : "
The technique according to the disclosure" enables flexible switching between interference control schemes for controlling interference between a micro 15 cell and a small cell.
Brief Description of Drawings
;" [0013] . --: :-.,._::: ::.. :■ _
[FIG 1] FIG 1 is an explanatory diagi'am for explaining existing network architecture 20 ofanLTE-based wireless communication system. ..._.__[FIG. 2] FIG. 2 is an explanatory diagram for explaining various bearers established on communication paths bet^veen iiodes illustrated in FIG I.
[FIG 3] FIG. 3 is an explanatory diagriam for explaining an example of atrangement
of small cells.
25 [I'lG. 4A] FKT. 4A Is an explanatoiy diagranTHlustraling a first~~example_of
_T a'''atigemcntofacooperMion_managerfor_intci face control ~__ :
[FIG. 4li] FIG. 4B is an explanatory diagram iliirsliating a second example ofj
auangcment ofthccoopeuition manager for interface conltol, , _ _,
—[i'lG. 4C]'FIG,—4C is an explanatoiy diagiani-illustrating a'^. third^examplc of
30 arrangement.oTthe cooperation nianagefTor interface control. -'-■ ' " - -
[FIG. 4l)j 'FIG. _4D is an explanatoiy diagram ilkTstiating a four'ftf cxa"mple of

■SPS44708\V{)00 5/37 -"
arrangement of the cooperation manager for interface control.
[FIG. 4E] FIG. 4E is an expIanatoiyTdiagram-illiisiriiling a filih example of
arrangement of the cooperation manager for inlerface control. - ^
[FIG. 5] FIG. "5, is a block.diagrain.illustrating an example of a confignration of the 5 cooperation manager according to a tirsfcmhoTliment.
[FIG. 6] FIG. 6 is a block diagram illustrating an example of a configuration of a base
station according to the first embodiment.— — - - -. ..
[FIG. 7] FIG. 7 is a sct|iiencc diagram illustrating an example of a flow of
communication control processing according to the first embodiment. 10 [FIG. 8] FIG. 8 is a flowchart illustrating an example of a flow of performance
measurement processing accordmg to the first embodiment. ■ -----
[FIG. 9] FIG. 9 is a flowchart illustrating an example of a flow of interference control
scheme selection processing according to the first embodiment.
[FIG. lOA] FIG. lOA is an explanatory diagram for explaining a first example of an 15 interface for interference control.
[FIG. lOB] FIG. 1 OB is an explanatory diagram for explaining a second example of
the interface for interference control. ■ •
[FIG. IOC] FIG. IOC is an explanatory diagram for explaining a third exiample of the
interface for interference control. : : , — ._^. — - - _ -..--
20 [FIG. lOD] FIG. lOD is an explanatory diagiam for explaining a fourth example of
__ the interface for interference control.:.; ..-:., •■■• • '- ' ; ' "' ' '" ". ■''/_
[FIG, lOE] FIG. lOE is an explanatoiy diagraifi'for explaining a fifth example of the
intei face for hitcrferencc control.
[FIG. 11] FIG. 11 is a block diagiam illustrating an example of a configurafion of the
25 cooperation manager according to a second embodiment.
[FIG. .I2J FIG. 12 is "a Howchart illustj'ating an example of a flow of .interference
control scheme selection piocesslng according to the second cnibodimcnt. .r"^_^"r'
" _——Description of Embodiments --^ '-2 --_^—i—
Hereinafter, ptdfcried embodiments of the present disclosuic will 'be ^, ~'

SP34'1708WO00 6/37 /
described in detail with reference to the appended drawings, Note that, in this — spccilicalion and the drawings, elements that have substantially the same fiinctum and structure are denoted with the same reference signs, and repeated explatiation_is_
omitted. ~~_ " ~TS_~~. 7 " ~_
—5 [0015] : ■ -:v:
Morpfiver, the e'^'nlanjifirm will he criyen In thp. follo^vi"" nvAf^f
■ 1. System overview . T
1-1, Configuration ofexisting system
1-2. Arrangement of cooperation manager (CM)
_10 1-3. Explanation of problem
2. First embodiment --
2-1. Configuration example of cooperation manager
2-2. Configuration example of base station
2-3. Processing flow
15 3. Second embodiment
3 -1. Deployment of interface for interference control
3-2. Configuration example of cooperation manager
; ^- ^ :-" 3-3. Processing flow -
"■ 4. Conclusion - . --
20 [0016]
<1. System overview>
[1-1. Configm-ation ofexisting system]
First, an example of a configuration of an existing cellular wiieless communication system will be described using FTG. 1 to FIG, 3. Note thai a
25 wireless communication system-based'~on LTE (also referred~to as E-UTRA
(Evolvcd-UMTS Teri-cstrial Radicr'Access)) will be dcscrib'ed heie as aii example of
the existingzsysicn^. "l[owevcr,'_Lhb technique according to the disclosure is not-
—=— -^ limited to" sucii an example, and'caifbc-widely applied to a wireless communication
— system" based- on-various ccljiilar-wireless coinhiunication- .schemes such as W-
J9,_ ^ COMA, GDMA200p,'^'iJVlAx,'andiTE-A.

SP344708VVO00 7/37 ,
FIG. 1 is an explanatory diagram for explaining existing network
architecture of an LTE-bascd wireless cornrniinicEition system. Wiih reference to
■__, FIG. 1, a wireless access network 10, a core network 20,' and an external networkilO
are illustrated. The wireless access~net\voik^lO is a network inckiding a radio Jink
5 between a user terminal (Uhl) and a base station (eN13), which is implemented as E-
UTRAN (Evolvcd-UTRA Network), for example. The core network 20 is a
network having various-fiinctioiis such as position registration, billing, and QoS
(Quality of Service) numagenient of a user terminal, which is implemented as EPC
(Evolved Packet Core) including P-GW, S-GW, and MKIE, for example. The
10 external network 30 is an IP (Internet Protocol) network also referred to as a PDN
(Packet Data Network), and various application (AP) servers can be implemented on
the external net\vork 30.
[0018]
Each node illustrated in FIG. I has the following function. Note that FIG. 1 15 illustrates only representative nodes in a wireless communication system, and other kinds of nodes can be also included in the wireless communication system.
- HSS (Home Subscriber^ Server): Server managing .identification
information, profile information, and authentication information of subscriber, etc;^-;
- MME (Mobility Management Entity): Entity transmitting and receiving
20 NAS (Non Access Stratum) signals to and from UE and performing mobility.
management, session control, and paging, etc. The MME is connected to a plurality
ofeNBs. " " ■ .:; '■";■:■...; ...^^ ^■.■^-■ ■ ;
- P-GW (PDN-Gateway): Gateway positioned at a connection pnint between
the EPC and the PDN to perform ai location of IP addresses to UEs, provision and
25 deletion of IP headers, etc. The P-GW*^ may perform billing management.
- S-GW (Serving-Gateway): Gateway positioned at a connection~pomt
between the ]l-\] ll^ANjmdihc TiPCto perform routing of_a packet_oii_a_user_pJatie,,:
When an UE performs handover between eNBs or between'UTPANs, the S-GW_
-becomes an anchor point. - - - - - - ■'-'.'' _ - '
30 " .''"' '~ - eNB (evolved Node B): Base station achieving a radio'liiik-in a macro cell.' Perform iadio resource management (KI^M: Keidio Resource Management),_iadio

SP34't708WC)00 8/37
bearer control, and scheduling, etc.
- ^ - UE (User Equipment): User; terminal using wireless comniunicatioti serviceprpvided^by eNB. '--^'" /'- ' ' . .' -- ' .. _ ___
:[ooi9] ;: ii_ " ":': T:^^:^^ "^^^ :_.:.
: 5 "" Between the nodes illustrated in FIG. 1, the following logical interface can"
be formed using a GTP (GPRS Tunnelintr Protocol") ti
■> " - SGi: Interface betweeiTtlieP-GW and the PDN "
- S5/S8: Interface for mainly transmitting user packets between the S-GW
andtheP-GW
10 - SI I: Interface for mainly transmitting control signals for inobility
management and session management bet^veen the S-GW and the MME.
- S6a: Interface between the MME and the HSS -
- S1-U: Interface on a user plane between the eNB and the S-GW
-SI-MME: Interface on a control plane between the eNB and the MME
15 - X2: Interface on a user plane and a control plane between base stations ,
Note that the details of these interfaces are mentioned in "Overall description; Stage
(Release 11)" (3GPPTS 36.300 Vll.0.0 (2011-12)).
[0020] ::y-- " ■ . ; "_
_...I FIG. 2 is an explanatory diagram for explaining various bearers established 20 on communication paths between the nodes illustrated in FIG. 1. In the example of FIG. .2,_an EPS (Evolved Packet System) bearer is established .between the UE and._ the P-GW. The EPS bearer and an external bearer can constitute an end-to-end communication path. An E-RAB (EPS-Radio Access Bearer) is established between the UE and the S~GW. A radio bearer is established between the UE and
25 the eNU. The ladio bearer and an SI bearer constitulc the K-RAIi, Moreover, the
racLlorbearer, the SEbcarer. and an~S5/S8 bearer constitute the EPS bearer." The"
id.entificrof the liPS' bearer is al locate) by_ the MMH7 .the packet iransTtiitted fiom_
the UJI oKfcccived by tii^UE is Iransferied tluough these bearers. _ -
- -Y00211- - ' "-" -.^Vl ' :--"' "■"- ^^ -
30 ■ _-- The hase"stationofacellular wireless coiniiiunlcation system represented by
the eNB ilhislraled in riGfJ and FIG. 2 provide"s 'wireless communication service to

9/37

SP344708WO00

terminals connected to tiiclnacro cell.^Thc radius of a macro cell is generally
several hundreds of meters "to over ten kilometers. However, near the boundary
— bet\vee_n niacrp cells, behind buildings, and in space suchiis undergi-ound or indoor,
the sti'ehgth of radio signals from the base station of a macro ceil is reduced, which
5 " can consequently cause a problem that the"comniunication is disabled or the data rate
IS msulTicient. In such a .situation Ihft <;mftll ccH c-m he '"t'^orl'i'^ed to comnleiTient
the macro cell and increase-communication capacity. 'The small cell is a concept
including a femtocell, a nanoceil, a picocell, and a micro cell, for example, and
introduced by arranging various kinds of small and medium scale base stations, as
10 described above,. Table 1 exemplifies some kinds of base stations of a small cell.
[0022] - --- _ _ .
[Table 1] . ""'
Table 1. Kinds and characteristics of base station of small cell

Kinds of base station IF type Access type Assumed place
RRH (Remote Radio Head) type-2 open outdoor
hot zone base station type-2 . open outdoor
femtocell base station type-i closed indoor
relay station type-1 open outdoor
[0023]

15
In Table. 1, the "IF type" is classification regarding anjnterface with a base station of a macro cell. The RRH and hot zone base stations having an X2 interface with a base station of a macro cell can be categorized ..to type-2, and the. femtocell base station and the relay station not having an X2 interface can be categorized to type-1. The "access type" is classification regarding acceptance of access from UEs.
20 The access type of the RRH, the hotzonc base statioji, and the relay station is open,
and all user terminals can be connected to small cells of such base~stations in -
.pmiciple. JJy_cmirast, the access type of thcJemtdcell basc_s_t.atiori is closed, and" -""-
oui)'_nmited user terminals can be connected to thcTcmloceMs in principle. - -}k
-- r0024J:---- _-_. - -' - ~':1-^ ' "'■

-25

" Lj —MG. 3 ,is an explanatoiy diagram-forcxplaining-an cxample'of-arrangcmcnt - of sniajiicells. With reference to FIG. 3, ajiiacro cell 12 r'eccTving .service from a-single-bas^ station (cNB) is illustrated. The'base station of a mlK-ro" ceil is

S1';M4708WOOO 10/37
coimected to a core network through a wired link. Moreover, FIG. 3 also^ illustrates
- four small cells 14a to 14d at least partially overlapping-with the macro cell 12.
___ The base station (S-BS) of the small cell 14a_is connected to the core network
through a wired link;... The base station of the small celLMblis.connectcd to the base
5 station ofthertiacro cell through a wired link. The base station "of the small "cell t"4c
is connected to the ba.se station of the macro cell through a radio link. The base
station of the small cell l4d is connected to the core network through an external
network (PDN). . ;. . ; ;
[0025]
10 When small ceils are arranged in a macro cell in this mamier, there occurs a
risk that radio signals transmitted and received by -the small cells -will cause interference to terminals connected to the macro cell. In order to avoid such a risk, some interference control schemes can be used. The most simple interference control scheme may be separation of operating frequency band. However, under
15 the shuation in which frequency resources are depleted, the frequency band different from an operating frequency band of a macro cell cannot be necessarily allocated to a small cell. Therefore, the interference control scheme for cooperatively controlling transmission power or transmission rates of a macro cell and a small cell, which is proposed in Patent Literature 1 described above, or the interference control scheme
20 for cooperatively controlling transmission and reception beams of a macro cell and a
small cell, which is proposed in Patent Literature 2 described above, is also effective.
The cooperation manager (CM: Cooperation Manager) is a fimction entity introduced
to achieve such cooperative control between a macro cell and a small cell.
[0026]
25 [1-2. An angement of cooperation manager (CM)]
._ _. Tlic coopcralion manager may be arranged onany orcommunication nodes
_- capable of communication with a base station.of a.small cell.-"FIG. 4A lo FIG. 4E —^illuslratc some typical examples of arrangement of the cooperation manager. _ -
..:._^[oo27y- .-''■=_' : . __ " ■_ ~r:. ■ ^
Tit) _l [Ui the example ofMG. 4A, the cooperation manager (CM) is arranged as a
\~hcw contiol node in the corc"nclwo)-k 20, In this cas^ signaling between the

SP344708WO00 1/37
cooperation jnanager and a typc-1 base station of a small cell can be performed
_through the external network 30. iiy contrast, signaling between the cooperation
manager "and a t>'pe-2 base station ojji small cell ca_n_be perfonned thi'ough the base
station (eNB) of a macrojccll. " "_ '_"" ;_ ,. v~A \ ~
5- L0028]— -- - — :.:";. ■;:>:ir:C^^
In the example of FIG, 4. the (■of^neration manager (CM) is arranged ns a
new function on a control node (an MMI2, for example) in the core net^vork 20.
Also in this case,'signal! rig'bet ween the cooperation manager and a type-1 base
station of a small cell can be performed thi'oiigh the external network 30. By 10 contrast, signaling between the cooperation manager and a type-2 base station of a
small cell can be performed through the base station (eNB) of a macro cell.
[0029] ' ... -:
In the example of FIG, AC, the cooperation manager (CM) is arranged as a
new function on the base station (eNB) of a macro cell. In this case, signaling
15 between the cooperation manager and a type-1 base station of a small cell can be
performed through the core network 20 and the external net^vork 30, By contrast,
signaling between the cooperation manager and a type-2 base station of a small cell
can be performed on an X2 interface.
[0030] .^ --: y „ " ;
20 In the example of FIG. 4D, the cooperation manager (CM) is aiTanged as a
: ,. new function on a base station of a small cell. In this case, signaling between Jhe
cooperation manager aiid a different type of another base station of a small cell can
be performed tlii-ough the wireless access network 10, the core net\york'20, and the
external net\vork 30. When the coopciation manager is airangcd on a typc-2 base
25 station, signaling between the cooperation manager and the base station of a macro
" cell can be performed on an X2'interface: ,._^ _~ __""
-"~ j[003ii " -_~ ~ -^_'-~~ [ '-r:_-~-'^^zzr -^~\ j __
- In the example of-FiG. 4, the cootTeiation-maiiagei (CM)-is arranged as' a — - new server-de_v ice in tlieexternal network-30.- In-this:casc, signaling bet^veen the "30 coopcjation manager ■ancl_a'type-i-base yiUatioirbf asmall cell can be performed j tluxHigh a c"ommunication link_betwcen thc^exteinalliehvork 30 andlhe type-rbase

SP3'M708W(X)0
12/37
station. By contrast, signaling between the cooperation manager and a type-2 base'
station of a small eel 1 can be performed tlirough the core network 20.,
^^[0032]^' J: __ ,___ ^ "" ' _ _
l^J: •""■;;: iNote that in any of FIG 4A to FIG. 4E, the cobpcration manager niayjbc. 5: controlled by an application server of the "IMS" (IP Multimedia-Subsystem). The" . anpIicatfQn sei'ver Goni'"ollitig t\iQ mo ivmn-^rii^i' ;■:■ .■....^.orii.Y-i ;., +i,« ,^,,(,,...,.,1
■network 30, for example." 'I hen, setting "of-the cooperation manager can be" perforined thi'oiigh the application server.
[0033]
10 [1-3. Explanation of problem]
In general, the scheme allowing closer cooperation between cells can suppress interference while using frequency sources more efficiently. However, high-speed and low-latency signaling is required for close cooperation. For example, to effectively operate the method proposed in Patent Literature I or 2 15 - described above, it is considered that the latency not exceeding several radio fi-ames, that is, several 10 msec is desirable. However, there may be actually" a case in which the desirable communication performance cannot be obtained for interference control, depending on a form of a small cell or arrangement of the cooperation"
manager. - ■ _.. - - — -::...
20 [0034]
As.understood from Table 1 and FIG, 3, there are "various examples of the _ kinds of small cells and the forms of arrangement thereof. Even when the base station of a small cell has a wired link, the wired link is possibly a high speed link such as I "tTH (Fiber To The Hojnc), or the wired link is possibly a low speed link 25 such as ISDN (Inlegiated~S"erviccs DigitarNctwoik), depelKlmg on an area. ^ - jVlofO-OVcr. as understoo"d~rrom VIG. 4A krFTG A\i, signaling paths for int"erfcrcnce ^ ciaitrol also vary depending on arumgemcnt of the cooperationjnanager. ~ _~r
X0035J - _ _ __ ___ - "' :,:
-Tlien, two embodiments to'be ""described from the following section provide-'60'- a^mcchanism for "flexibly switchirig,^rfo"r'interference control, interference ^control schemes depending on actually obtained communication performance. 1 ' /' r

SPy4'1708WO00 13/37
[0036J "
<2, First cmbodiment>
[2-L Configuration example of cooperation manager]
—. _ FIG, 5 is a block diagram ilhistrating an" example of a configuration of a _.
~5 " cooperation manager 100 according to a first embodiment. With reference to FIG 5,
the cooperation, manager 100 includes a rnnimiinication uni' 110 ^i ctprfjge unit 12.0,
-^; and a controller 130. - ~ _ " " " "
[0037] ;:
(1) Communication unit
10 The communication unit 110 is a communication module for
-communication of the cooperation manager 100 with other nodes. The
communication unit 110 may include a wireless communication module including an
antenna and an RF (Radio Frequency) circuit, or include a wired communication
- module such as a LAN (Local Ai'ea Network) connection terminal.
15 [0038] ■ _. :
(2) Storage unit
The storage unit '120 stores programs and data for operation of the
"cooperation manager 100, using a storing medium such as a hard disk or a
-semiconductor memory. For example, the storage 120 may store thi'esholds to be
20 compared with communication performance parameters when a selection unit 124
described later selects an interference control scheme ■i__
■ [0039]
(3) Controller '
Tlie ctintrollcr 130 corresponds to a ptocessor such as a CPU (Central
2o Processing IJnit) or a DSP (Digital SignafProccssor). ~fhe controllcri30 operates ~ various function_s of the cooperation managei' 100:fay executing programs'storcd in_ _ - the storage_unit 120 or other storing' media, - In Jhe embodiment,_the .controller 130 -
- includes-threc functioii-niodutes of a performance acquisition unit 132, a selection ,_
— unit 134, and an interference control'uiiil-136 =" : — -- - -
30 [0040];^~^^^'' -■ -_:"^'^>^_ "1_^> "^v"'*' ^, -■ -
(3i:I)Perfoi'manccac'quisition'ufiit ■' ^ '' "_

SP3dd708WO00
14/37 ■■■■■■:. ^
The perforinancc acquisition unit 132 acqitires a communication performance parameter indicating cojiimunication performance on a signaling path of
_,^ base station of a small cell that is specified _as a target of interference control. The
communication performance parameter is a parameter typically indicating at least 5 one of throughput and latcTicy. ^When "si'gnaling for interference control is performed through the-cooperation manager, the nerformance acnuisition unit 132 itself may measure communication -perfoimancc -regarding the signaling. Alternatively, the performance acquisition unit 132 may request another control node such as a P-GW, an S-GW, or an eNB, for-example, to measure communication
10 performance. The communication performance may be measured by repeatedly transmitting and receiving test signals (ping signals, for example) a plurality of number of times, or measured based on the statistics of actual traffic, for example. [0041]
The communication performance can be measured between different nodes
15 in accordance with the kind of a base station of a small cell. When the base station
of a small cell is a type-2 base station; for example, the base station has an X2
interface, and thus can perform .signaling without an external network interposed.
- In such a case, the communication performance is measured with respect to at least
one bearer constituting the EPS bearer exemplified in FIG. 2. Which bearer is
20 measured regarding communication performance depends on aitangement of the cooperation manager. By contrast, when the_base station of a small cell is a type-1 base station, the base station does not have an X2 interface, and thus signaling is normally perfonned tlu'ough an external network. Tn such a case, the communication pertbrmance is measured in an eiid-to-end manner (between the base
25 station of a small cell and the cooperation manager or between the base station of a
small ceil and the base station of ajnacro cei!,"for exainpLe). ___
" [00421 - ~"-lrT^"----- - '""■ , 7" - ^ " ~z ' '"
The peifornian'ce acquisition unit-132, outputs -the -communication
performance parapieler indicating communication perfoiniancc measured in this-'
30"- manner to the sclcciiouimit'134. ^__ <- ' '^ "?r -~'
' ~ [00431 . ^'" : '~ ' ~: '~ "■■-:' V- "

SPn4470«WO00 15/37
(3-2) Selection unit .
The selection unit 134 selects an interference control scheme for controlling
__:__.,: .ilterfereiice of radio signals j?etween a macro cell and a small cell, based on t\\Q_
:.._.' communication performance pafameter acquired by the performance"acquisition iinit_
~""5" 132. The candidate for an interference control scheme that can be selected by the
selection unit 134 may be two or more arbitrai'y interference c^til^'o! 'schemes efirh
—having a different signaling overhead amount or resistance to'latency. For exami^le,
as the first standard, when the communication performance parameter indicates that
communication performance (throughput, for example) is higher, the selection unit
10 134 can select an interference control scheme requiring larger signaling overhead.
Moreover, as the second standard, when the conununlcation performance parameter
indicates that communication performance is lower (high latency, for example), the
selection unit 134 can select an interference control scheme having higher resistance
to latency. These standards may be used Individually or in combination.
16 [0044] " .1- ""
As an example, a first interference control scheme that can be selected by
the selection unit 134 is a. frequency band separation scheme. In the first
interference'control scheme, "the macro cell and the small cell are provided
respectively with operating frequency bands different from each other. When
20 frequency resources are sufficiently available, and operating frequency bands can be
allocated in a quasi-static manner (that is, in a fixed manner with a span of several.
hundreds of msec or longer), it is possible to suppress overhead of signaling in the
first interference control scheme to significantly small. In addition, even when the
latency of signaling is relatively high, the fiist interference control scheme can
25 opciate elTectivcly. -
10045]
—A-secondiintcrferenceicbntiol schenic that can bcsclccted^y. the selection unit 134 is a powe"fAatc adju'sfmcnt scheme. In the secojid interference-control scheme, tjansmrssion-power or-transmlssion uites arc adjusted-betiveen-a macro cell
r-JO and a small cell, ~ Regarding the details of the second intcifeience c6ntu)I scheme, it is suggested to refer to Patent Liteiature_i desciibed above. ~ Jinhc second

VSP;M4708WO00 16/37
interference control scheme, signaling of control data such as a transmission power value, an al!()wed interference amount and an-assumed interference amount is
pcrjormed, The data amoirnt of control data can depend on tlie number of user links,
the.mimber ofLrcsource_blocks for_cach channel, and tlic number of channels,. for 5 example, in addition"to the number of b1l5"of a transmission power value, an allowed interference amount, and an assumed interference amoimt, As comnared with the first interference control scheme, higher -throughput and lower latency on signaling paths are requested ill the second inteiference control scheme.
[0046] - -^ - : -: - - " -
10 A third interference control scheme that can be selected by the selection unit
134 is-a beam adjustment scheme.- In the third interference control scheme, transmission beams or reception beams are adjusted between a macro cell and a small cell. Regarding the details of the third interference control scheme, it is suggested to refer to Patent Literature 2 described above. In the third interference
15 control scheme, signaling of control data such as a beam steering matrix, an allowed interference amount, and an assumed interference amount is performed. The data amount of control data can depend on the number of user links, the number of resource blocks for each channel, and the number of channels, for example, in addition to the number of bits of a beam steermg matrix, an allowed interference
20 amount, and an assumed interference amount. Moreover, the data size of a beam
.. steering matrix becomes larger as the.number of transmission and reception antennas
is increased. As compared with the second interference control schenie, higher
throughput and same or lower latency on signaling patlis arc rct|uestcd in the third
interference control scheme.
25 [00471 " ~
.~ Note that the intcrreiencc control scheme is notliniited to these examples,
_ _and anotIier_interfcrcnce control scheme,maybe sclccted.r,"Moreover,-it is possiiblc"
. to "select an interference control schememsing the coiiibinatiou olMwo^or more of the .
___ 'labove-described first to third interference-control-schemes;--- -"- _—
■ /' Wlien the selection iJnlt 134 selects an interference controrsclicme based on

SP344708WO00 17/37
the communication performance parameter, it outputs an identifier identifying the
selectedschemeto the interference control unit 136. - - — -
■ 1 .._="_ (3-3) Ihteiference contro ._ -
.5 'The interference controL unit 136 cooperatively controls intCTfcrcnce"
between a macro cell and a small cell in accordance with ihe hiferfrrcnf'*' roritfo! scheme selected by the selection unit 134. When the selection-unit 134 selects the first interference control scheme, for example, the interference control unit 136 transmits interference control signals specifying, as an operating frequency band, a
10 frequency band different from a frequency band allocated to the macro cell, to the
base station of the small cell. Moreover, when the selection unit 134 selects the
second interference control scheme, for example, the interference control unit. 136
transmits, to the base station of the macro cell and the base station of the small cell,
. interference control signals instructing them to mutually adjust transmission power
15 . and transmission rates in accordance with the method described In Patent Literature I.
■Furthermore, when the selection unit 134 selects the ■third interference control
scheme, for example, the interference control unit 136 transmits, to the base station
of the macro cell and the base station of the small cell, interference control signals
instructing them to mutually adjust transmission beams^and reception beams in
20 accordance with the method described in Patent Literature 2. As a result, it is possible to suppress interference between the macro cell and the small cell.,
-;;-[oo50] ■" -;:^:. v;
The acq\iisition of a commimication perforrnance parameter by the performance acquisition unit 132, and the selection of an interference control scheme
25 by the selection unit 134 may be repeated periodically in a fixed cycle.
Alteniatively,Jn lesponsc to a iequcst'from a base station or a~user.terminal iiaying
: -detected interference exceeding a giycn-lcvelr-thcipcjformancc acquisition unit 132
- - ."-may acquire-aTcoimminication performance pjiiameter, and the selection imit 134-
—-may-seiect an interference control scheme.— ■':'_- - -
^0 """[00511 ■-'^ -^_.' "■_._ ^"frr"'^'' -
~[2-2. Configuiatioif example of base statioilj^ ' ' ,

SP344708WO00 18/37
A base statfbn 200 of a small cell constitutes a communication control
_ system-together with the cooperation manager 100 described above. FIG. 6 is a
- -_bkicl<_ diagram illustuiting an cxampie_o_f a coiitiguralion of the base station 200 of a
Jsmall cell according to Hie first _cmbodiment. With reference "to FIG. 6, the base
5 station"200 includcs"a~\vireless communication unit 210, a network communication
unit 220, a storage u!iit 230, and a controller 240.
[00521 "" — - " - - ""
(1) Wireless communication unit
The wireless communication unit 210 is a wireless communication module
10 for providing wireless communication service to terminals connected to the small
cell, The wireless communication unit 210 includes an antenna and an RF circuit.
The transmission power of radio signals transmitted from the wireless
communication unit 210 can be controlled such that interference caused to a macro
cell is suppressed within an allowed range. Moreover, the wireless communication
15 unit 210 typically includes a plurality of antennas, and can direct transmission beams
and reception beams to a direction identified by a beam steering matrix (or precoding
matrix).
.- . [0053].. '. - -- .:/-/■ ..~^^::/:..TH:./■-;: ;...;. _ .
(2) Network communication unit i:~:/
20 The network communication unit 220 is a communication module for
. communication between the base station 200 of a small cell and a control node such
as a cooperation manager, The network comrnimication unit 220 may include a
wireless communication module that can be made common with the wireless
cotnnuinication u^it 210, or may jncludc a wited communication module such as a
25 LAN comicction teiminal. '
1"_[00541 1"_ -' - "~^- y- --
, (3) Storage unit _::r_" zzr'", ".L~ _ ~
- The sto) age-unit 230 stores progranis_and data for'operation-of-the base station 200, using a,storing mcdium^uch^asa^hafd disk or a scmiconductorincniory.' 30 For example, the stqrage^unit 230 can sfoiFtraffsniissKm power values, transmission rates,"or beam steering matrices, for cxaniple, that_aie specified by the eo'opeiation

SP344708WOnO 19/37 ':::--
manager or adjusted bet\veen the base station of the"smaTl^eUaiicra""basesFation of a
macro cell, for example. -
•^" T00551 ; : ^ ^
.:.:::_: (4) Controller " ~_ ~ -- - _
-5 The conti'oller 240 corresponds to a processor such as-a"CPU or a DSP.
■ -- The control nnit 240 nnc'ii'e* vqi'[nii<: fimcdfinc r»+'tiin K.I<;,-. ...t-.tJo" I^^A I^T, «^r„^.,<;„,,
.-■■■-.' • ^
- programs stored in the storage" unit 230 or other storing media. Tn the emboduncnl,
the controller 240 includes two function modules of a setting unit 242, and a
communication control unit 244. . '. .
10 [0056] " " ""
(4-1) Setting unit - - -
The setting unit 242 sets a communication parameter for wireless communication with teiminals connected to the small cell in accordance with interference control signals received by the network communication rmit 220..
15 When the interference control is started, the cooperation manager specifies any of interference control schemes. The subsequent interference control may be performed throiigh the cooperation manager, or performed directly between the base-station of a small cell and a base station of a macro cell. For example, when the first interference control scheme is specified, the setting unit 242 sets an operating
20 frequency band of the wireless communication unit 210 to a frequency band different from an operating frequency band of the macro cell. Moreov.er,.when the second I interference control scheme is specified, the setthig unit 242 sets transmission power or a transmission rate of the wireless communication unit 210 to a value adjusted so that the inteifercncc caused_to the macio cell is suppicssed witliin an allowed lange.
25 MOI cover, wiien the third inteFteicnce contio"nchcmc is specified,*" the setting unit"
242 sets a direction ol' transmissiQn__bcams-or reception beams of the wTtcless
conimmiication unit 210_using a specified beam sleeThglnatrix, . '_ z"'
11-"- [00571 -- _ -—- -- '" ~1
, (4-2) Communication control unit --" ^
.10 ' --The communication control unit 244 controls wireless C()ifinuinication witlv
terminalsjcofincctedtothe small celL I'orexample, the commnnicalion contt'olunit'

SPH44708WO00 20/37
244 allocates frequency resources within a range of operating frequency band set liy the setting unit 242, lo each terminal, and delivers scheduling information in the small cell, 'i'lien. the communication control unit 244 controls the wireless
cohihiunication unit 210.to receive up-Iink signals and transmit down-Hnk signals in
; 5"accordance" "with the . allocation of Trequehcy" resources. ' Moreover, the
. ^'P^^fi^i-'iication control unit 244 can RISO control transml^ssion Dower. ^ +rf;nsml"R?'"'^
- rate, or directivity of transmission beams"'oi~reception beams of."each terminal
" "" connected to the small cell in accordance with interference control signals received
by the network communication unit 220.
lo joossT" _ ;
: [2-3. Processing flow] -
(1) Entire flow
FIG. 7 is a sequence diagram illustrating an example of a flow of
communication control processing according to the first embodiment.
15 [0059] ^.-^ " ;
The communication control processing exemplified in FIG. 7 is started with
initial setup at Step SIOO. In the initial setup, the base station 200 of a small cell is
arranged Iti a macro cell, arid the communication connection is typically.established
after authentication processing between one cooperation manager (CM) 100 and the
20 base station 200 of the small cell.
: [0060] 1^__. ___ _
Once""the initial setup is completed, communication performance on a signaling path of the base station 200 of the small cell is measured. In the example of FIG. 7, the cooperation manager 100 transmits a performance measurement
25 request to a P-GW (or an S-GW) (Step SI 10), liTTesponsc lo the perfonnancc
measurement request from "the cooperatioTi 'manager 100. the" P-GW measures.
communication perfortnancc^on the signajing-path of the base statiouz200.6f the small cell (Stcp-S120). 'Iheh;the P-GW informs the cooperation manager 100-of a value of a communication .performance parainetej- indicatiiig throughput andJatency
HO" ofcachbearer as funeasurcmqnljju get, for example (Step SI 30).' - ,- - ^!"-, -
-'[0061] - "^- " " ■-:--- ' ■" " ' " - -^^ -'-'.

SP;M4708WOOO 21/37
When the communication performance parameter is acquired, the
cooperation manager-iOO selects an intcrrerence_control _scheme based on the
_ acquii-ed communication .peiformance --paaimctcr_(Step _S14Q).__jrhen, _the
cooperation"manager 100 transmits interference.controLsignals to the base station of
5 the small, cell. 200 and lhe"b"ase station of the "macro "cell in accordance with the
selected interference control scheme (Step SI 50). : In this jnanner, the interference is
suppressed between the base station 200 of the sTnall cell and the base station of the
macro cell in accordance with the interfercnce""con(rol scheme selected by the
cooperation manager 100. .._.__..
10 [0062] _ .. -.--_-.--..
Thereafter, the measurement of communication performance and the interference control can be repeated periodically or based on a request. [0063]
(2) Performance measurement processing _. _
15 FIG. 8 is a flowchart IHustrating an example of a flow of the performance
measurement processing performed at Step S120 in FIG.7. In the example of FIG, 8, it is determined first whether the base station 200 of a small cell has an X2 interface (Step SI22). When it is determined here that the base station 200 of the small cell has an X2 interface, communication performance is measured regarding at least one
20 bearer constituting an EPS bearer (Step S124). By contrast, when it is determined . that the base station 200. of the small cell_.does_not have an X2 interface, communication performance is measured in an end-to-end "manner (Step S126). [0064]
(3) Interference control scheme selection processing
2ft FKi. 9 is a flowchart illuslrating an example of a flow of the interference
~ conU-ol scheme selection pj'ocessing performed al_Step S140 in MQ 7.- In the ;:
— _i-example__of-FIG, 9, the performance acquisition unit J 32 of the coopeiation matiager - j
' 100 .acquires-a .communication performance .parameter-indicating communication
performance-on a .signaling path of the base station 200 of-tlic small cell (^Step Si41). " -
,30 -'[(X)651 zlKsl-'l ' ■ ~-\'_' ' '^ '-"'" —~i-- ' '■-''
• ' Ncxlr llic selection unit 134 determines" whether the com-mun'icatidn

SP34'1708WO00 22/37
performance indicated by the communication performance parameter satisfies the first condition (Step SI42), The. first condition may be a condition tliat-thc
\:_L througliput is higher than a first througliput threshold, and the latency is sjnaller than
, "a "fii'st latency threshold (the comparison with a threshold regarding one of them may
" 5 be omitted). Here, when' it is determined that the communication performancc~does not satisfy the first condition, the selection unit 134 selects the first interference
control scheme (fi-equency band separation scheme) (Step 8143).""-:—.-
[0066]
When it is determined at Step SI42 that the communication performance
10 satisfies the first condition, the selection imit 134 further determines whether the
communication performance satisfies the second condition (Step 8144). The
second condition is a severer condition than the first condition, and may be a
condition that the tln-oughput is higher than a second throughput threshold, and the
latency is smaller than a second latency threshold (the comparison with a threshold
15 regarding one of them may be omitted). Here, when it is determined that the
coinmunication performance does not satisfy the second condition, the selection unit
134 selects the second interference control scheme (power/rate adjustment scheme)
(Step-S145). By contrast, - when - it is determined that the communication
perfonnance satisfies the severer second condition, the selection unit 134 selects the
20 third interference control scheme (beam adjustment scheme) (Step 8146).
[0067J
<3. Second embodiment"-
[3-1, Deployment of interface for interference control]
The problem of communication pciformance for interference control
25 signaling can be solved by deploying, in a base station of a small cell, a high-speed
interface v^'ith'a cooperation tnaU'igef- Tlic interface for inteijcrcnce control may be
. deployed byncwly arranging a phj'sical couununicatloirlinelsuch as optical fiber.
Alternatively, the interfa'cclfor interference control may be deployed as a logical
- interface on an-existing communication line (a GTP tunnel-ox a VI^NXVirtimi-Privatc
HO ' ^lSiefwoik),"^ctcV [or example). The interface for interference control may be a
dedicated interlace for signaling ibr"interference control or an'interface used also for

SP;H44708WOOO
23/37 :
signaling for another purpose. [00681 ' --- - __:
EIO- lOA to-FIG^_LOH illustrate examples of the interface for interference
control in each of arrangement of cooperation managers exemplified in FIG.14A to
5 ITG. 4Errc5pectively. _ ■ _ -
r00691 'T" -■-' -~r'--- :-.:'_
In the example of FIG-IOA, the interface for interference'control can be deployed betvyeen the cooperation manager arranged as a new control node and each base station of a small cell. -.-=:
10 [0070]" 7 "^;^ 7
- In the example of FIG. 1 OB, the interface for interference control can be
deployed between the cooperation.manager arranged on the MME and the type~l base station. The type-2 base station can perform communication with the cooperation manager through an X2 interface and an SI -MME interface.
15 [0071]" r""■ .
In the example of FIG. IOC, the interface for interference control can be
deployed between the cooperation manager arranged on the eNB and the type-1 base
station. The type-2 base station can perform communication with the cooperation
manager through an X2 interface. -
20 [0072] :^
. In the examplelof FIG. lOD, the interface for interference control can be
deployed between the base station of a small cell on which the cooperation manager
is arranged and another base station ofa small cell. -
[0073]
25 In the example of FIG. lOE, the interface for interference control can be
clcployed between the cNB and thc_t>'p_cM_base station. ThcTvpe-2 base station can
... perform communication with the eNBithrough an~_X2 Tntcrfacc. The'eNJi'caii-
perform communication with the cooperation manager throiigh-an SU\J intclface, an
S5AS8-interfacc, and an SGi-intcifacc. —iJ , ' "--^\ " ■ , '"
^?[0074]' ^ " "._; =:"='-^^^^^'"'r-'"^'"r^"^\ -^v-
, " When the interface Tor interference control exenipllfled in_FIG. lOA to h'lG.

SP344708WO00
24/37 ;.:>■: ^•
lOE is deployed, it is assumed that sufficient comnninicatlon perfolmaticc can be obtained.between the base station of a small_cell and the _coopcration niaiiagcr. Therefore; communication performance is not measured again rcgardmg such a small _ cell, arid any of preliminarily defined effective interference contipl schem.cs may be selected. ::By contrast, regarding a base station of a smiill cell in which"thcTnterface" for interference control is not deployed, it is effective to select an infcrterence contrn)
scheme:-in accordance with communication performance, as described in the first — embodiment. Then, the cooperation manager according to llic second embodhnefit described In the following switches modes between a mode for fixedly-selecting an ^ 10 interference control scheme and a mode for dynamically selecting an interference control scheme in accordance with communication performance, depending on whether a base station of a small cell has an interface for interference control. [0075]
[3-2. Configuration example of cooperation manager] . .„ _
15 - FIG. 11 is a block diagram illustrating an example of a configuration of a
cooperation manager 300 according to a second embodiment. With reference to
FIG. 11, the cooperation manager 300 includes a communication unit 310, the
storageunit 120, and a controller 330, _; ;:' ;:; .- ;
[0076] " - 1 .;:----■; "
20 (1) Communication unit
— The. communication . unit 310 is a . comrnxmlcation j tnodule for. communication of the cooperation manager 300" with othei* nodes." The communication unit 310 may include a wireless communication module, or ma>' include a wired communication module, hi the embodiment, the communication 25 unit 310 can also terminate an intci face for interference with a^base station of a small"
" _cdl_ _-' ^- - , J '_ _2^ Jl _1 -
^■^' [007 f\^'- -_ ~ -—'_"' - }r~~' -~' ", _^~,
"--", V(^) Conttoljer -._''. . __ ___.
^-_^:- - —^rhe-controller 330-corrcsponds4;o_ a pri)ccssor such as a CPU or-a DSR—-■JJO- The controller 330 *^op'erates various ftinctions "of the coopeiatiori manager 300 by ~~ ~^_' executin'g progtams_stored'in the stoia'gc unit 120 oi other storing media." In'the '

Sr344708WO00 25/37
embodiment, tivc controller 330 includes four function modules of the performance
acquisition unit 132. a selection unit 334, the interference control unit 136, and an IF
determination unit 338.
[0078] - __ ::_ _: - -- ";
~~5 (2-1 )"IF determination unit
The IF determination tinit 338 determines whether a base station of a small
cell -specified-as a -target of interference control has a logical or physical
communication interface for interference control. Then, the IF determination unit 338 outputs a result of determination to the selection unit 334. The determination 10 by the IF determination unit 338 may be performed based on identification information or capability information, for example, of the base station of the small cell acquired in the initial setup exemplified in FIG. 7, for example. [0079]
(2-2) Selection unit
15 When the IF determination unit 338 determines that the base station of the
small cell has an interface for interference control, the selection unit 334 selects a
preliminarily defined interference control scheme for Interference control of the base
station of the small cell.-^ The interference control scheme selected here may be the
above-described second interference control scheme or the third interference control
20 scheme, or another arbitrary scheme effective for interference control. By contrast,
when the IE.determination unit 338 determines that the base station of the small cell
" does not have an interface for interference control, the selection unit 334 selects an
interference control scheme based on a communication performance parameter
acquired by the performance acquisition unit 132, similarly to the selection unit 134
25 accordhig to the first cmbodimenl. The, candidate for an intcilcrence control scheme to_be selected by the selection unit 334 may be (he first to third intcifcrcncc" control .schemes described jibove, foi-_exaihj3lc, 'liiesclectioirunit 334_-o_utputs an identiilcr identifying-the selected iiiterfeieiice control "scheme to the interfeience — control unit-136. Then, the ■interference''control unit-'l36 performs-cooperative-j)() ihterference'control betweeii tKeTuacfo cell atid the sniall cell in accordance with the ■ interference control scheme selected by the selection unit 334. "' " _

smsmimmm
SP344708WO00 26/37
[0080] " " ~ . "
[3-3. Processing flow] - "_____"_
FIG^12 is a flowchart illustrating an example of a flow of inloilerence
.;;._ control scheme selection proce"ssing according to the second_emb6dimcnt. "C!
5- [0081] - .' - - ._ - - - — ,..:..
In the example of l
The two embodiments of the technique according to the present disclosure have been described in detail using FIG. 5 to FIG. 12. According to the 15 embodiments described above, an interference control scheme for controlling interference between a macro cell and a small cell is selected based on communication performance on a signaling path of a base station of the small cell. This enables flexible switching of schemes in the manner that a simpler interference control scheme is selected when communication perfomiance is not sufficient, and a 20 closer interference control scheme is selected when sufficient communication
performance can be obtained. Therefore, no matter how the small cell is arranged,'.
. it is possible to maintain preferable communication quality using . an optimal interference control scheme and increase coinmunication capacity. Moreover, i\o matter wheie the coopeiation manager is positioned in nctwoik architecture, it is 25 possible to select an optimal intcrfcience control scheme.
7" _[^088j I""_^ .- IT — Is " ^.. _r r ^
_"!. ' For_example,-_"\v'iicn the communication performance paiameter indicates
- - that communication perfonnance is higher, the interference control scheme requiring -
larger signaling overhead^can bcsclected. When the conununicalion performance
iiO_ is high, it is possible to transmit large signaling ovcihekd at^a high-speed andwith small delay. Therefofc7in_this case, it is possible,'with the use of the intcrtefcnce

SP34d708W()00 28/37
control scheme based on closer signaling," to~effectively suppress interference using
. frequency resources cfilciently-- _ -
[0089] 1 --- ■__
Moreover, whehjhc communication performance parameter indicates "that -' 5 communication performance 1s"Io\\er, the intcffcrence control scheme having higher . resistance to latency can be selected. When the communication performance is low, the interference control scheme requirhig immediacy does not operate appropriately Therefore, in this case, it is effective to securely suppress interference using the interference control scheme having high resistance to latency (frequency separation 10 scheme, for example).
[0090] --; - - - ._._„
Furthermore, according to the second embodiment, when a base station of a
small cell does not have an interface for interference control, an interference control
scheme can be selected based on a communication performance parameter.
15 Therefore, it is possible to use, when an interface for interference control exists, an
interference control scheme high in resource efficiency utilizing the interface, and
use, when an interface for interference control does not exist, an appropriate
interference control scheme in accordance with communication performance.
[0091] . - .. .—: 1
20 Note that the sequence of control processing by each device described in the
description may be achieved using any of software, hardware, and the combination
of software and hardware. A program constituting software is preliminarily stored in a storing medium provided inside or outside of each device, for example. Then, each progrtim is read in a IMM when executed, and executed by a processor such as
25 a CPU.
- 100921" ~ 11":" - - ^_ - -_ z
- -"- The prefened embodiments of thc.prcscnl disclosure have been descjibcd_—_7v
- - above wjth reference to the accompanying drawhigs, whilst the teclmical scope of the -'—
disclosure is not limited to the above examples It is clear"that-a-person-skilled in' 1
■ 30 _the art-canTnid various alteration examples and modification examples withm the technical id6a described in the claim.s, and~lt should be understood that they will.

SPH44708WO00 29/37
naturally come under the technical scope of the present disclosure.
[0093] ■ V:;/^ V;/:-'^ ,^ - - —
, Additionally,jhe_pi;esentteclmolgg> be contlgurcd as belowi
5 AcomniunicatipncohtroldeviceiiichKling:
a performance acquisition nnit tl1,^t communication perforrnance on a signaling"path of a base station ofa small cell tliat at least paitially overlaps with a macro cell in a wireless comnuinication system;
a selection unit that selects an interference control scheme for controlling 10 interference between the macro cell and the small cell, based on the parameter - acquired by the performance acquisition unit; and
an interference control unit that transmits an mterference control signal to the base station of the small cell in accordance with the interference control scheme selected by the selection unit.
:i5 (2) - " : :_::
The communication control device accordmg to (1), wherein the selection unit selects the interference control scheme requiring larger signaling overhead when the parameter indicates that the communication performance is higher.
._ (?) ___ . . . ._ .. :_,._: : -I:..::r:- ---
20 The communication control device according to (1), wherein the selection
unit selects the interference control scheme having higher resistance to.latency when
the parameter indicates that the commimication performance is lower. -
The communication conliol device according to any one of (1) to (3).
25 wherein the selection unit selects the inteifciencc contiol schemybascd on the parameter when the base station of the small cell does not liavc a logical or physical
: - ■ communication interface for interfeience contiol. - _r--
--V--(5) - . _
~-' - '^. The communication control device-accoi-ding" to any-one of (1) to (4),
30' wherein^thc selection unit selects, bakt[on the parameter, the interfeience control
ischeme among candidates including two ormore of '" _""

SP3'14708WO00 30/37
a first scheme in which operating frequency bands dilTercnt from each otiier arc each allocated to the jnacn) cell and the_small cell,
__ _a'_sccond scheine_in which Lransniission power or a Jnuismissionjiiite is
adjustedJjctvvcen thejnacro cell and the shial! coll, and _
~ 5 " " a third schemcin which afransmission beam or a reception beam is adjusted
between the macro ell and the smalj ceil.
- (6) - - - -" _ - - - ^ -
The communication cbhti'ol device according to any one of (1) to (5),
wherein the performance acquisition unit acquires, when the base station of the small
10 cell has an X2 interface, the parameter indicating communication performance of at
- least one bearer constituting an EPS (Evolved Packet System) bearer on the signaling
path.
(7) ; ^ ■___:_
The communication control device according to any one of (1) to (6), 15 wherein the peiformance acquisition unit acquires, when the base station of the small cell does not have an X2 interface, the parameter indicating end-to-end communication performance on the signaling path.
" The communication control device according to any one of (1) to (7),
20 wherein the parameter includes at least one of throughput and latency.
^M^ /..-■■I- .-...,;-_._..::_..,■„;..„__ .^_...__ . ^ ..
The cominunication control device accordihg to any one of (1) to (8),
wherein the communication control device is positioned in a core networic in the
wireless communication system.
To (10) ~~ "~" "~ "~
I ~ The communication contjol device accojding to any one".of (1) to (8),_
~ whei ein the communication .control devicejs positiohcdjn the macro_ccl I.
-^.(11) - - _ ^.-^/. __. 1"- ;__!-:'- . _'^- ' :
_ _ __ '.liie cpmniimication conliol device accojdin'glto any i-onej)f (1) to-(8),
30 wheiein the communicationcontrol deviccris positioned jn'an exlel iial IP netwtn k in^
~ the wireless communication^ystem^ -- — = - - -

SP344708WO00 31/37
(12) -
A communication control method inchiding:-
.__ by a coni'ol node in a wireless communication system. - -
— acquiring a paranxeter Indicating coimminication pertormancc on a signaling
5 palh ofa base station ofa small cell that at least partially overlaps withn macro cell; sclcctina^ an rnlorferenff cnntro' vichc"? +'"'■ r'MT*'-'^"'"" ifitf>,-i',M'<-ii-,,.«i betweeji the macro eel I and thc'sma! I cell, basc'd on the acquired parameter; and ■ "; ' transmitting an interference control signal to the base station of thesmall
cell in accordance with the selected interference control scheme. / ; . .
10 (13) "_ _ ' ~ " " ' "^
A base station of a small cell that at least partially overlaps with a macro cell in a wireless communication system, the base station including:
a communication unit that receives, from a control node controlling interference between the macro cell and the small cell, an interference control signal. 15 of an interference. control scheme selected based on a parameter indicating communication performance on a signaling path between the base station of the small cell and a base station of the macro cell; and
a controller that controls wireless communication between the base statioii" of the small cell and a terminal connected to the small cell in accordance with the 20 interference control signal received by the communication unit.
04)-- .-. ----- --... ..:_./_ -^\ .:::_.;: r:i_:_...z_
A communication control system including;"
• a base station ofa small ceil that at least partially overlaps with a macro cell in a wireless communication system: and
'■^5 a control node including
- _ -. , a performance acquisition_unit that acguircs:a"parameter Indicating
- communication pei formancc.on a signaling path of tlie base station of the smalLccll, -:
'— ' --a selection unit-thai selects an-interference control scheme for —
:' controlling interference belween-tlic'lriacro cell and the sniaM cell,-bascd on^he-^
"C_30 J parameter acqiiii^ by the performance acquisition unit, and- - ' " s^-T-^I' ~ an interference control unit thai transmits an interference contror':-

SP344708WO00 32/37
signal to the base station of the small cell in accordance with the interference control
scheme selected by the selection unit. :: r -_: ;. :_.
Reference Signs List__::_
100, 300coope.ration manager ^communication control device)
132—-performance acquisition unit __:_..;;
134, 334s"election unit 136 interference control unit 10 338 IF determination unit ... 200 base station
220 communication unit 240 controller
:njiF:][iti:ryr^.:^^^

Sr3'14708WO00 33/37

CLAIMS
Claim 1 - ____--__ "-"
,. A communication control device coiiiprising;
'' performance acqlilsilion unltjhal acquires__a_ paiameter "indicating 5 communication performance on a~signaling pattrof a base station of a small cell that at least partially overlaps with^ rnacro ceil ui a wireless communication .svstem-
-a selection unit that-selects-an interference control scheme for cont^^^^^
interference between the macro cell and the small cell, based on the parameter
acquired by the performance acquisition unit; and
10 an interference control unit that transimts an interference control signal to
the base station of the small cell in accordance with the interference control scheme selected by the selection unit.
Claim 2 ._. __ _
15 The communication control device according to claim 1, wherein the
selection unit selects the interference control sclieme requiring larger signaling
overhead when the parameter indicates that the communication performance is
higher. - :, ::'::: ,
20 Claims
The communication .control device„according to__claim 1, wherein the
selection unit selects the interference control scheme having higher resistance to latency when the parameter indicates that the communication performance is lo^^er.
25 C:iaini 4
_Tlie commujijcMLOii control device' according" to claim 1, wherein the
_ _ selection unitselccts the interference coutrobscheme .based on the parameter when,!":—
the base station of-thc small cell docs not have a logical oi-physical comtnufiication "" ^''
-interface for interference control. . 1- • j /-"- ' ~'lt~^
'-"Claims ' ' -' ' '-'^-:<----_ _\U".- ■ - 7''. '

SP344708WO00 34/37
The communication control device according to claim I, wherein Ihe selection unit selects, based on the paiamclcr, the interference control scheme among
:.:: ^candidates^including two or more of ' ' ■-- ' ■'
^ _ ' "-~.a first scheme in which opciating frequency bands different fi-6m_cach other
~ 5 are each allocated to the macro cell and the small cell, ' _
a-second schLTiio in whirh transmission power or a iT"j';'''r»" s-it'^ ii
adjusted between the macro cell and the small ceil, and
a third scheme in which a liansmission beam or a reception beam is adjusted
between the macro ell and the small cell.
10 "
Claim 6 ..__._. ^ __ .__.; .
The communication control device according to claim 1, wherein the performance acquisition unit acquires, when the base station of the small cell has an X2 interface, the parameter indicating communication performance of at least one 15 bearer constituting an EPS (Evolved Packet System) bearer on the signaling path. ..
Claim 7
The communication "control device according to claim 1, wherein the-performance acquisition unit acquires, when the base station of the small cell does 20 not have an X2 interface, the parameter indicating end-to-end cominunication performance on the signaling path..
Claims
The commiinicalion control device according to claim 1, wherein tlic
25 parameter includes at least one of throughput and latency.
Claim 9-T- ^- " " —±- " _ -_ " ' r^.-
The-communication coiitrol device according to claini^ 1, wherein the communication-control dcvice-is-positioncd in a-core-nctvvork' In the-wireless
^30 ' com'miihication sy.stemT

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'■^^.■^MWB''=:-:U'::^i'''^ SP344708WO00
^,^^:^^■-.■u::^^'^v::l'■:'■■;:■; V 35/37 : ■:_-■:■
Claim 10 - ^ - -
The commimication control device according to. claim 1, wherein the
commimication cpntroljdcvice is positioned in the^maero cell,
5 Claim 11- — " " --
The communication control device accordinc to claim 1, wherein the communication control device is positioned in an external IP network in the wireless communication system.
10 Claim 12
A communication control method comprising:
by a control node in a wii'eless communication system,
acquiring a parameter indicating communication performance on a signaling
path of a base station of a small cell that at least partially overlaps with a macro cell;
15 selecting an interference control scheme for controlling interference
between the macro cell and the small cell, based on the acquired parameter; and .
transmittmg an.interference control signal to the base station of the small cell in accordance with the selected interference control scheme."
20 Claim 13
...A base station of a small cell.that at least partially overlaps with a macro celL. in a wireless communication system, the base station comprising:
a communication unit that receives, from a control node controlling ■
interference between thd macro cell and the small cell, an interference control signal
25 of an interference control scheme selected based on a pauimetcr indicating
communication performance on a signaling_path between the, base station of the
T^ small cell an_d a base station of the macro cell: and :— - z.z r.-'^'
-_ - a controller that controls whcless communication between the base station__ —!— oTthcsmall cell and a-tciminal connected to the small cell in accordance-with the — ao diiterfeiencccoiitiol sigijalicceivedby'thc.cwmmmiealioiiimif. — ~ ,-

36/37

SP344708WO00

Ciahn 14 : T
- A communication control system comprising:: 777-/: :i__i:.._:.:.:.. :„.. .' ■ a base station of a smalt cell that at least partially overlaps with'a macro cell In a 'wii'eless.conimlmication system; "and. . ' ', ~i; -:—----■■-■■-. r--,-------- ■ -- .
^control node including ' . " ::v:/": :' ' .rr^
■ a perfonnance acquisition unit that acquires a parameter indicating

10

communication performance on a signaling path ofthe base station of the small cell, .
a selection unit that selects an interference control scheme for controlling interference between the macro cell and the small cell, based on the parameter acquued by the performance acquisition unitj and
an interference control unit that transmits an interference control signal to the base station ofthe small cell in accordance with the interference control scheme selected by the selection unit.

Dated this 12,08.2014

[RANJNA MEHTA-DUrr]
OF REMFRY & S AGAR
ATTORNEY FOR THE APPLICANT[S]

r > '

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