COMMUNICATION CONTROL DEVICE, COMMUNICATION CONTROL 3 , 5 METHOD, AND COMMUNICATION CONTROL PROGRAM [000l] The present disclosure relates to a communication control device, a 10 conu1111nication control method, and a conunt1nication control prograrli. Background Art [0002] Recently, high-speed cellular radio co~ll~nunicatiosnc henies such as Long 15 Term Evolution (LTE) and WiMAX are being practically imnple~liented, and the communication rate of radio co~nmunication service's enjoyed by mobile users has greatly improved. Furthermore, if fourth-generation cellular radio conlullunication schemes sucll as LTE-Advanced (LTE-A) are introduced, an even greater improvenie~iitn con~municationr ate is anticipated. 20 [0003] 011 the other hand, the nunlber of mobile users is increasing rapidly, and the usage of applications demanding high data rates is becoming Illore widespread. As a result, the development of cellular radio co~nniunication schemes is not fi~lly satisfying all mobile users' needs. Consequently, in order to supplement macro cells \ 25 and increase con~munication capacity, the introduction of small cells is being advanced. Small cells are a concept that enconlpasses femto cells, nano cells, pic0 cells, micro cells, and tlie like. Small cells are typically introduceci by installing a base station (also called an access point) that is small cornpared to a macro cell base station (for exari~plea, n evolved Node B (eNB) in LTE). However, in areas where a 30 macro cell ancl a small cell overlap, there is a risk of radio signals transmitted and received by the small cell interfering with a tenninal connected to the macro cell. [0004] In order to avoid tlie risk of interference due to tlie introduction of small cells, Patent Literature 1 below proposes a technique that cooperatively controls tlie transmit power and transmission rate of a nlacro cell and a sniall cell. 5 Citation List PaiC',i Li[Criiii,ii: [OOOS] Patent Literature 1 : JP 2011-211369A 10 Summary of Invention Technical Problem [00061 However, when ellvisioning conditions in wl~clir in~ltiples niall cells are 15 present, the technique of moderating interference by considering only the relationship between macro cell and small cell is insufficient at avoiding tlie risk of interference. [0007] Conseq~~entlyit, is desirable to provide a mechanism enabling inter-cell 20 interference to be suitably moderated under conditions in wliicli multiple small cells are present. Solution to Problem [OOOS] 25 According to the present disclosure, there is provided a conimunication control device including an allocation unit that allocates trarisniit power to each of one or more srnall cells so as to moderate interference on a macro cell of a radio communication system from each small cell that at least partially overlaps with the macro cell, a judgrnent unit that, in a case in which there exists a second sruall cell 30 that exerts interference exceeding an allowed level on a first small cell, judges whether the interference is unidirectional or bidirectional, and a control unit that controls the interrerence between tbe first small cell and the second small cell with a technique tbat differs according to a judgment result by the judgtnent unit. [0009] According to the present disclosure, there is provided a connnullication 5 co~itrol metl~od including allocating transmit power to each of one or more small cells so as to moderate interference on a macro cell of a radio conullnnication system ,i.oil, cati~, Y,iii,ii CC'i (hi,[ lcasi pariii,iiy '*iii: iiiC ji ,ac.o cci!, judgiiig, jii a case in which there exists a second stnall cell that exerts interference exceeding an allowed level on a first s~ilall cell, wllether the interference is unidirectional or 10 bidirectional, and controlling the interference between the first small cell and the second small cell with a technique that differs according to a result of the judging. [OOlO] According to the present disclosure, there is provided a communication control system including base stations of a first small cell and a second small cell that 15 at least partially overlap with a macro cell of a radio conmunication systein, and a co~nlnunicationc ontrol device that includes an allocation unit that allocates transrnit power to each of the first small cell and the second small cell so as to moderate interference from the first small cell and the second small cell on the macro cell, a judgment unit that, in a case in wluch one of the first small cell and the second small 20 cell exerts interference exceeding an allowed level on the other, judges wlletlier the interference is unidirectioiial or bidirectional, and a control unit that controls the interference between the first small cell and the second snmll cell with a technique that differs according to a judgtnent result by the judgment unit. 25 Advantageous Effects of Invention [OOll] According to teclnlology in accordance with the present disclosure, it is possible to suitably moderate inter-cell interference under conditions in wllicll multiple small cells are present. 30 Brief Description of Drawings [0012] [FIG. 11 FIG. 1 is an explanatory diagratn for describing an overview of a system. [FIG. 2A] FIG. 2A is an explanato~y diagram for describing a first case of interference that nlay occur whet1 multiple s~nalcl ells are present. 5 [FIG 2B] FIG. 2B is an explanatory diagratn for describing a second case of interference tliat may occor when nlultiple stnall cells are present. l.i.;.ic~.:. zc, 2c is exij~ui,.apory Ji ayr.'*.,.r ' - hi.(p cscri:iiig illiiJ ciiso [ o interference tliat niay occur when multiple sniall cells are present. [FIG. 31 FIG. 3 is an explanato~y diagram for describing several examples of tlie 10 placement of a cooperation manager for tlie purpose of interference control. [FIG. 41 FIG. 4 is a block diagram illustrating an example of a configuration of a cooperation manager according to an etnbodiment. [FIG 5A] FIG 5A is a first explanatory diagram for describing the estimation of cumulative interference caused by multiple small cells. 15 [FIG. 5B] FIG. 5A is a second explanatory diagram for describing the esti~nationo f cunlulative interference caused by multiple small cells. [FIG. 61 FIG. 6 is a table illustrating an example of interference control schemes tliat may be selected according to the type of interference. [FIG. 71 FIG. 7 is a flowchart illustrating an example of the flow of a conniiunication 20 control process according to an emboditnetit. [FIG. 81 FIG. 8 is a flowchart illustratingan example of a detailed flow of the interference classification process illustrated in FIG. 7. [FIG. 91 FIG. 9 is a block diagram illustrating an example of a configuration of a base station according to an embodirnent. 25 Description of E~nbodiments [0013] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the appended drawings. Note tliat, in this 30 specification and the drawings, elements that have substantially the same fi~nction and structure are denoted with the same reference signs, and repeated explanation is omitted. [OOI 41 Also, tlie description will proceed in the followirig ordel: 1. Ovel-view of system 5 1-1. Exanlples of small cells 1-2. Types of interference ' 7 " :: ...<. ... ..#... I.- -1.. .,........ ! 1"'d. uUUb;bL&lLtULi * . L < L : 8 & i & i (b?\4) ,;~.i6;,iz~b'i~ 2. Cooperation manager config~~ration 2-1. Exemplaly fi~~ictioncaol nfiguration 10 2-2. Process flow 3. Small cell base station configuratioti 4. Co~iclusion lo0151 <1. Overview of system> 15 /I-1. Examples of small cells] First, FIGS. 1 to 3 will be used to describe an overview of a system. FIG. 1 illustrates a radio communication system 1 as an example. The radio communication system 1 may be a system based on an arbitrary cellular radio cotntnunication scheme, such as LTE, W-CDMA, CDMA2000, WiMAX, or LTE-A, 20 for example. [00 161 Referring to FIG. 1, a base station 11 (for example, an eNB in LTE) that provides a radio co~nmunication service to a terminal within a macro cell 10 is illustrated. 'flie radius of the macro cell is typically from several hundred meters to 25 over ten kilometers. However, in spaces such as near the boundary of tlie macro cell, in the shadow of a building, underground, or indoors, a problem may occur in which com~liunicationb ecomes unavailable or the data rate becomes insufficient, as a result of lowered strength of the radio signal from the macro cell base station. Ulider such conditions, small cells may be introduced in order to snpplenleilt the 30 macro cell and increase communication capacity. As discussed earlier, small cells are a concept that encompasses femto cells, nano cells, pico cells, micro cells, and the like, and are introduced by installing various types of small- to medium-scale base stations. Table 1 exemplifies several categories of small cell base stations. [00 171 Table 1. Categories and features of small cell base stations. Base station IF type Access type I Expected location I category (PPY! Remote radio llead I . . T.y- p e 2 Outdoors statiou In Table 1, "IF type" is a classification related to the interface witli a macro Open station cell base station. An RRH and a hot zone base station with an X2 interface witli a I .- - Fetnto cell base I Type 1 Indoors macro cell base station may be classified as Type 2, while a femto cell base station Hot zone base Closed Relay node 10 and a relay node lacking an X2 interface may be classified as Type 1. "Access Type 2 Open Outdoors 5 Type 1 Open type" is a classification related to how tlie small cell is accessed from UE. The Outdoors access type of an RRH, a hot zone base station, and a relay node is open, and as a general mle, all user devices are able to connect to the small cells of these base stations. On tlie othe'r hand, the access type of a femto cell base station is closed, 15 and as a general rule, only a limited group of user devices are able to connect to a fe~ntoce ll. [0019] FIG. 1 illustrates small cell base stations 16a, 16b, 16c, and 16d. The small cell base stations 16a, 16b, 16c, and 16d respectively provide radio communication 20 service to terminals within small cells 14a, 14b, 14c, and 14d that at least partially overlap with tlie macro cell 10. In FIG. 1, terminals that connect to the macro cell are indicated by black circles, whereas ternlinals that connect to the small cells are indicated by white circles. 25 In the case in which a small cell is placed within a niacro cell in this way, there is a risk of radio signals transniitted and received by the small cell interfering with a terminal coni~ected to the macrocell. In order to avoid such risk, several interference control schenies are usable. The simplest interference control schenie may be separation of tlie frequency bands in use. However, under conditions in 5 , which frequency resources are depleted, it is not necessarily possible to always assign to the small cell a frequency band that differs from the frequency band in use by iiii.,,k ,&Lblu ... ;:. ,,,., Lwt1i3, ~otlsupi~,;;[;~iaj ri,a tKL.fi;rcliu; 2Jfl~:G~ s c ~ c ~ i[hlac; csoilcr;i~~~~rc;~,, controls the trans~nitp ower or trans~nissionr ate of the macro cell and the small cell is beneficial, such as that proposed by the above Patent Literature 1. However, in 10 the case in which multiple small cells are present, an interference co~~trsoclh eme that considers only the relationship between macro cell and small cell is insufficient. [0021] [I-2. Types of interference] FIGS. 2A to 2C illustrate thee typical cases of interference that may occur 15 in the case in which multiple small cells are present. 111 the first case illustrated in FIG. 2A (interference case A), bidirectional interference occurs between two mnutually neighboring small cells 14a and 14b. More specifically, in the area where the small cells 14a and 14b overlap, a terminal 18a connected to tlie small cell 14a receives interference caused by radio signals translilitted and received within the 20 small cell 14b. Sin~ilarly,a terminal 18b connected to the small cell 14b receives interference caused by radio signals transmitted and received within tlie small cell 14a. [0022] 111 the second case illustrated in FIG. 2B (interference case B), unidirectional 25 interference from a small cell 14c to a small cell 14b occurs. More specifically, radio signals transmitted and received within the s~nalcl ell 14b do not reach any of the terminals 18c connected to the small cell 14c. Radio signals transmitted fro111 the base station 16c of the small cell 14c may exert interference exceeding an allowed level on a terminal 18b connected to the small cell 14b. This may occur 30 because excessively large transmit power is allocated to tlie base station 16c as a result of the presence of an obstacle between the base station 11 of the macro cell and the base station 16c of the small cell 14c. [0023] In the third case illustrated in FIG. 2C (interference case C), cumulative interference from two small cells 14a and 14d negatively influences a terrilinal 5 connected to the macro cell. More specifically, for a terminal 12a positioned at a place between the small cells 14a and 14d, the sum of the interference causetl by ~ n d i i :s ignals ;I". 3 t c m i n l 183 c-,2n5cted to tllc rmr:!! cell 143 2nd iiitcrfci..~i;cc caused by radio signals from a terminal 18d connected to the small cell 14d exceeds an allowed level. 10 100241 In order to suitably moderate the interference that is characteristic to these conditions ill which multiple small cells are present, it1 the tecllnology according to the present disclosure, a functional entity called a cooperation manager (CM) is introduced. 15 [0025] [I-3. Cooperatio~ml anager (CM) placemeni] The cooperation manager may be placed on any con~munication node able to com~nunication with the base station of a small cell. FIG. 3 is an explanatory diagram for describing several examples of the placement of a cooperation manager. 20 In FIG. 3, an LTE-based network architecture is illustrated as an example. In an LTE-based network architectore, the base station (eNB) 11 of a macro cell 10 is comlected to a core network 20. The core network 20 is implemented as the Evolved Packet Core (EPC), includi~lga P-GW, an S-GW, and an MME, for example. The core network 20 is additionally connected to an external network 30. The 25 external network 30 is an Internet Protocol (IP) network, also called a packet data network (PDN), and varioious application (AP) servers may be implemented on the external network 30. [0026] Each of the nodes illustrated in FIG. 3 respectively has a role like the 30 following. Note that although only representative nodes are illustrated herein, other types of nodes may also be included the network architecture. - Home Subscriber Server (HSS): a sewer that manages subscriber identification information, profile information, authentication infomlation, and the like. - Mobility Management Entity (MME): an entity that exchanges non-access 5 stratum @AS) signals with UE, and conducts rnobility management, session management, paging, and the like. The MME is connected to multiple eNBs. - pD$J-Gii[cwdy (p-G:j;;); g.,i c\,,aj,?, p ~ s ~ ~ ~(~olcijb~ii(c.[;o~ibi cp \.,, [z.;, xciylpi arj, FLilItiti bria leGlfii~:.i.l.r i<::81ic d*,,i s .ii itu ., ~,l~crfc.c'p"c jL{ kka; !A,~SJ c scr iOcd Lis;llg FIG. 2A. On the other hand, in the case of unidirectional interference, the judgment unit 134 classifies the interrerence between the lirst and second small cells into the 10 interference case B that was described using FIG. 2B. Note that the above designated ratio may be statically configured (such as 10% to 20%, for example), or dynamically configured according to a parameter such as the transmission duty cycle per small cell. [0043] 15 Also, in the present embodiment, the judgment unit 134 may additionally judge whetl~er or not the cumulative interference from multiple small cell onto a terminal connected to the macro cell exceeds an allowed level. For example, the judgment unit 134 estimates the interference level caused by radio signals fiont each of the mdtiple small cells at a place between the base stations of the multiple sniall 20 cells, and compares the culllulative value of the estimated interference level to an allowed level. In the example of FIG. 5A, the normal line dropped fiom the eNB 11 to the line joining the base station 16a of the srnall cell 14a and the base station 16d of the small cell 14d is extended to the edge of the macro cell 10. The cumulative interference may also be evaluated by supposing that a terminal connected to the 25 macro cell is present on a reference line RT, along such a normal line. Such an evaluation is valuable in the case in which interference caused by downlink signals of the small cells is dominant. On the other hand, in the example of FIG 58, boundaries 15a and 15d of the areas in which a designated signal level (-1 10 dBm / 6 MHz, for example) is detected are computed for the small cells 14a and 14d, 30 respectively. The cuimnlative interference may also be evaluated by supposing that a terminal cormected to the macro cell is present in the overlapping portion of these areas (the shaded portion in the drawing). Such an evaluation is valuable in the case in which tlie cause of the dominant iriteifererice is not specified. The judgment unit 134 follows such' a procedure to detect a pair of small cells that exerts cumulative interference exceeding an allowed level on a macro cell terminal, and 5 classifies the cumulative interference into the interference case C that was described using FIG. 2C. juu44j (3-3) Interference control unit The interference control unit 136 controls inter-cell interference in 10 conditions in which multiple small cells are present, according to a technique that differs depending on the judgment result by the judgment unit 134. FIG. 6 illustrates an example of interference control schetnes that may be selected by the interference control unit 136 according to a judgment result (that is, an illterference classification) by the jjudgme~lt unit 134. 15 [0045] For example, the interference control unit 136 controls the scheduling of at least one of the first and second small cells so that the same radio resource (that is, a resource block) is not sunultaneously used by a pair of s~nallc ells involved in the interference case A. I The s~llalcl ell base station 200 constitutes a conmlunication control system together with the cooperation inanager 100 discussed above. FIG. 9 is a block diagram illustrating an example of a configuration of a small cell base station 200 25 according to the present erubodiment. Referring to FIG. 9, the base station 200 is equipped with a radio conmlunication unit 210, a ~~etwocrok~ l~muilicatiounn it 220, a storage unit 230, and a control unit 240. [0060] (I) Radio communication unit 30 The radio cornnlunication unit 210 is a radio co~~ununicationnlo dule for providing a radio connllunication service to a terminal com~ecteclt o the small cell. The radio communication unit 210 includes an antenna and an RF circt~it. The transmit power of a radio signal transmitted from the radio connl~unication unit 210 is moderated to be within a range controlled by the cooperation manager 100. [0061] 5 (2) Network con~municationu nit The network con~munication unit 220 is a connnunication nlodule for coliiii.,uii~cxc:ioni iI >. LI I'i ~ iI u,I.L (.z1 bawds [Li&,ii2 c0 r;..*i i,L1 .;'I b. ..i.i.L.' li :u; s the cooperation manager 100. The network con~mnnicationu nit 220 may include a wireless conl~nunicationm odule that may be shared with the radio con~muoication 10 unit 210, or include a wired cotn~nunicationm odule silch as a LAN port. KO0621 (3) Storage unit The storage unit 230 uses a storage medium such as a hard disk or se~niconductor nlelnory to store programs and data for the operation of the base 15 station 200. For example, the storage unit 230 may store allocations of resources and transmit power designated by the cooperation manager 100. [0063] (4) Control unit The control unit 240 corresponds to a processor such as a CPU or DSP. 20 The control unit 240 causes various functions of the base station 200 to operate by executing a program stored in the storage unit 230 or another storage nlediun~. In ,- the present embodiment, the control unit 240 includes two fi~nction idodules: a configuration unit 242 and a comn111nication control unit 244. [0064] 25 (4-1) Configuration unit The configuration unit 242 configures communication parameters for radio comn~unicationw ith a ternlninal connected to the snlall cell, in accordance with an interference control signal received by the network con~municationu nit 220. For example, the configuration unit 242 configures a broadcast channel in a resource 30 block specified by the interference control signal. Also, the configuration unit 242 configures the transmit power of the radio communication n i t 210 to a value specified by the interference control signal. In the case of receiving a request to decrease the transmit power from the cooperation manager 100, the configuration unit 242 decreases the transmit power configured in the radio conm~~~nicatuionnit 210. Note that the configuration unit 242 may also not accept the above request in 5 the case of judging that a desired conmlunication quality cannot be lnaintained if the transmit power is decreased. jliilb5] (4-2) Conmlunication control unit The communication control unit 244 controls radio communication with a 10 terminal connected to the small cell. For example, the cotn~nunicationc ontrol unit 244 broadcasts a synchronization signal for cell search and synchronization as well as system information on a broadcast channel config~~rebdy the config~lrationu nit 242. Also, the communication control nnit 244 allocates to each terminal resource blocks on data channels that nlay be positioned between broadcast channels. 15 Subsequently, the conlmunication control unit 244 causes the radio communication unit 210 to receive uplink signals and transmit downlink signals in accordance with the resource block allocation. Additionally, the con~nlunication control unit 244 controls the transmit power of each terminal connected to the small cell, to be within a range allowed by the cooperation manager 100. 20 [0056] <4. Conclusion> The foregoing thns describes an embodiment of technology according to the present disclosure in detail using FIGS. 1 to 9. According to the e~nbodiment discussed in the foregoing, interference between small cells is at least classified 25 according to whether the interference is unidirectional or bidirectional, and interference is moderated with a technique that differs depending on the classification. Consequently, compared to an interference control scheme that does not depend on interference classification, it is possible to more suitably moderate inter-cell interference under conditions in which lnultiple snlall cells are present. 30 [0057] For example, in the case of unidirectional interference, the base station of tlie small cell on the interfering side may be requested to decrease the transmit power. Consequently, by decreasing the transmit power of the small cell tliat is obtained too many com~nu~licatioonp portunities, it is possible to moderate interference while maintaining the co~nmunicationo pportunities of the small cell on the interfered side. 5 [0068] As another example, in the case of bidirectional interference, the scheduling .. "{ hos i,iii'i cciis ;:ivo;v;c( .wi[i; iiIi iil[ei,,%i ;ciiz bC con$i.o!:;s~c ; tis; small cells do not use tlie same radio resource sinlultaneously. Consequently, interference may be moderated by fairly reducing com~nunication opportunities for 10 small cells that are equally responsible for interference. [0069] As another example, in the case in which the cunlulative interference from multiple small cells exerts interference exceeding an allowed level on a macro cell terminal, the cumulative interference is also nloderated. Consequently, it is possible 15 to safely introduce mnltiple small cells while suitably protecting communication by macm cell terminals. For example, by increasing the interference immunity of a radio signal on the macro cell side, the relative level of cunlulative interference with respect to the allowed interference level may be moderated. In this case, it is possible to prevent tlie adverse effects of interference without reducing the 20 communication oppol-htnities of the small cells involved with tlie cumnulative interference. [0070] According to the embodiment discussed in the foregoing, resources and transmit power are first allocated to a broadcast channel of a small cell, and then the 25 interference caused by transmission on a data channel from the small cell is estimated in units of single or n~ultipler esource blocks on the basis of the allocation. Consequently, compared to a technique that does not disti~iguish types of channels when estimating interference, it is possible to rationally estimate the interference level tliat may vary per resource block, 30 [0071] Note that the series of control processes conducted by the devices described in this specification may be realized in any of software, liardware, and a combination of software and hardware. A program constituting software is stored in advance in a storage medium (a non-transitory mediu~il)p rovided internally or exter~iallyto each device, for example. Each program is then loaded into RAM at runtinie and 5 executed by a processor such as a CPU, for example. [0072] 77,.1i. iti [GKtigoiI,g [I u, lu: ~sL. .L,. ;>ji..b: l,..~p ier,r[i;d ;x;';"&iilcii[s i;c ;:lG ->-- .,..,.- -.' ,,"">.Gil> disclosure in detail and with reference to the attached drawings. I-Iowever, the technical scope of the present disclosure is not limited to such examples. It is clear 10 to persons ordinarily skilled in the technical field of the present disclosure that various modifications or alterations may occur insofar as they are within tlie scope of the technical ideas stated in the claims, and it is to be understood that such modifications or alterations obviously belong to the technical scope of tlie present disclosure. 15 [0073] Additionally, the present technology may also be co~lfigureda s below. (1) A conimunication control device including: an allocation unit that allocates tra~lsnlitp ower to each of one or more small 20 cells so as to moderate interference on a macro cell of a radio communication system from each sn~alcle ll that at least pastially overlaps with the macro cell; a judgment unit that, in a case in which there exists a second small cell that exerts interference exceeding an allowed level on a first small cell, judges whether tlie interference is unidirectional or bidirectional;.and 25 a control unit that controls the interference between the first small cell and the second small cell with a technique that differs according to a judgment restllt by the judgment unit. (2) The communication control device according to (I), wherein 30 in a case in which the interference between tlie first small cell and the second small cell is unidirectional, the control unit requests a base station of the second small cell to decrease transmit power. (3) The comnlunication control device according to (1) or (2), wherein in a case in which the interference between the first small cell and the 5 second small cell is bidirectional, the control unit controls scheduling of at least one of the first s~lialcl ell and the second small cell so that the same radio resource is not si-;lj$anc.;tisly ;;I t:lc first smn!! ell 2nd tl:~r rso=d smn!! cc;!!. (4) l'he commonication co~ltrodl evice accorditig to (2), wherein 10 in a case in which the base station of the second small cell does not accept the request, the control unit controls scheduling of at least one of tlie first small cell and the second srnall cell so that the same radio resource is not used simultaneously in the first sillall cell and the second small cell. (5) 15 The communication control device according to ally one of (1) to (4), wherein the judgment unit additionally judges whether or not cuni~~lative interference fiom a plurality of small cells on a terminal connected to the macro cell exceeds an allowed level, and 20 in a case in which the cumulative interference is judged to exceed the allowed level, the control unit controls at least one base station of the macro cell or base station of the plurality of small cells so that the cumulative interference is moderated. (6) 25 The con~municationc ontrol device according to (9, wherein the judgment unit estimates an interference level caused by a radio signal from each of the plurality of small cells at a place between the base stations of the plurality of small cells, and compares a cumulative value of the estimated interference level to tlle allowed level. 30 (7) The communication control device according to (5) or (6), wherein in a case in which the cumulative interference is judged to exceed the allowed level, the control unit increases an interference imnlunity of a radio signal transmitted between the terminal and base station of the lmacro cell. (8) 5 The conn~lunicationc ontrol device according to (5) or (6),w herein in a case in which the cumulative interference is judged to exceed the .. 2iLio .we J icvc;, ihc cuIliici usit c"t-,~ro~ss~ 2~13~ktLif ~ii~lci igL 8rliat, ! s; y.2 1,.iu: >:. f ' i. ~l ~. .i!il .i iS ti that a radio resource used by the termiilal in the macro cell is not used simulta~leouslyi n the plurality of s~llalcl ells. 10 (9) Tl~e com~nunication control device according to any one of (1) to (8), wherein the allocation unit allocates a resource and transmit power to a broadcast channel of each small cell on the basis of allowed transmit power for each s~llalcl ell 15 conlputed per resource block, and the judgment unit estimates interference caused by transmission of a radio signal fron~ each small cell on the basis of the allocation of the resource and the transnlit power to each small cell. (10) 20 The communication control device according to (9), wherein the allocation unit allocates the resource and the transmit power so that a conmlunication opportunity of an open-access type small cell is prioritized over a closed-access type small cell. (11) 25 A com~nunicationc ontrol method including: allocating tra~ls~llipto wer to each of one or more srllall cells so as to moderate iuterference on a ulacro cell of a radio communication system from each small cell that at least partially overlaps wit11 the nlacro cell; judging, in a case in which there exists a second small cell that exerts 30 interference exceeding an allowed level on a first small cell, whether the interference is u~lidirectional or bidirectional; and controllitig tlie interference between the first small cell and tlie second small cell with a technique that differs according to a result of the judging. (12) A co~nrnunicationc ontrol system incloding: 5 base stations of a first small cell and a second small cell that at least partially overlap with a macro cell of a radio commurtication system; and I .. . a coiniiiiii:iciiii~iic uiliioi ilcvi~cii iiii ;iicititics an allocation unit that allocates trans~nitp ower to each of tlie first small cell and the second small cell so as to nloderate interference from the first 10 small cell and the second small cell on the macro cell, a jndgment unit that, in a case in which one of the first small cell and the second small cell exerts interference exceeding an allowed level on the other, judges whether the interference is unidirectional or bidirectional, and a control unit that controls the interference between tlie first snlall 15 cell and the second small cell with a technique that differs according to a judgment result by the judgment unit. Reference Signs List to0741 20 10 nlacro cell 11 macro cell base station 14a to 14d small cell 100 cooperation manager (comnlunication control device) 132 allocation unit 25 134 judgment unit 136 interference control unit 16a to 16d. 200 small cell base station CLAIMS Claim 1 A con~mn~~nicatcioonnt rol device comprising: an allocation unit that allocates transmit power to each of one or more stnall 5 cells so as to moderate interference on a macro cell of a radio communication systeni from each small cell that at least partially overlaps with the macro cell; . :., ',..i .. .,:c !?,.,: ' it, .ll,,ll, u , , t L uiuh3 ~~~~~c ir'25ri~L;; ;i: tiic((: cxisi:; :! sr:;;clrir? ::iiifillG ~'lb1i3 i exerts interference exceeding an allowed level on a first small cell, judges whether the interference is unidirectional or bidirectional; and 10 a control unit that controls the interference between the first small cell and the second small cell with a technique that differs according to a judgment result by the judgment unit. Claim 2 15 The con~municationc ontrol device according to claim 1, wherein in a case in which tlie interference between the first sniall cell and the second small cell is unidirectional, the control unit requests a base station of the second small cell to decrease transmit power. 20 Claim 3 The communication control device according to claim 1, wherein in a case in which the interference between the first small cell and the second small cell is bidirectional, the control unit controls scheduling of at least one of the first small cell and the second small cell so that the satne radio resource is not 25 used simultaneously in the first small cell and the second small cell. Claim 4 Ihe conimunication control device according to clairn 2, wherein in a case in which the base station of the second srnall cell does not accept 30 the reqnest, the control unit controls scheduling of at least one of the first small cell and tlie second snlall cell so that the sanle radio resource is not used sirnultaneously in the first small cell and the second small cell. Claim 5 The comtliunication control device according to clailii 1, wherein 5 the judgment unit additionally judges whether or not cumulative interference from a plurality of small cells on a tenninal connected to the macro cell exc.eeds en al!nwrd k~rle;n d in a case in which the cumulative interference is judged to exceed the allowed level, the control unit controls at least one base station of tlie macro cell or 10 base station of the plurality of small cells so that the cumulative interference is moderated. Claim 6 The co~iununicationc ontrol device according to claim 5, wherein 15 the judgment unit estimates an interference level caused by a radio signal from each of the plurality of sniall cells at a place between the base stations of the plurality of small cells, and compares a cumulative value of the estiniated interference level to tlie allowed level. 20 Clailii 7 Tlie comtilunication control device according to claim 5, wherein in a case in which the cumulative interference is judged to exceed tlie allowed level, the control unit increases an interference immunity of a radio signal transmitted between the te~minaal nd base station of the macro cell. 25 Claim 8 'fie conununication control device according to claim 5, wherein in a case in which the cuniulative interference is judged to exceed the allowed level, the control unit controls sclieduling of the plurality of small cells so 30 that a radio resource used by the terminal in tlie macro cell is not used simultaneously in the plurality of small cells. Claini 9 The con~municationc ontrol device according to claim 1, wherein the allocation unit allocates a resource arid transmit power to a broadcast 5 channel of each small cell on the basis of allowed transmit power for each small cell computed per resource block, and i.h c j.i ijgiiieii; it es,in*iics iiiici~ci' caiiscJ by ir<.-u isiiiis-*."; l . cla nx[..; o signal fiom each small cell 011 the basis of the allocation of the resource and the transmit power to each s~nalcle ll. 10 Claini 10 The comnlunication control device according to claim 9, wherein the allocation unit allocates the resource and tlie transmit power so that a cornmunication opport~~niotyf an open-access type small cell is prioritized over a 15 closed-access type s~nalcl ell. Claim 11 A communication control metliod comprising: allocating transmit power to each of one or Inore sniall cells so as to 20 moderate interference on a macro cell of a radio conimunication system from each small cell that at least partially overlaps with tlie macro cell; judging, in a case in which there exists a second small cell that exerts interference exceeding an allowed level on a first small cell, whether the interference is unidirectional or bidirectional; and 25 controlling the interference between the first snlall cell and the second sniall cell with a technique that differs according to a result of the judging. Claini 12 A conm~~nicatiocnon trol systenl comprising: 30 base stations of a first small cell and a second srnall cell that at least partially overlap with a luacro cell of a radio cornmunication system; and a co~llcnunicationc ontrol device that includes an qllocation unit that allocates transmit power to each of the first small cell and the second srllall cell so as to moderate interference fiom the first small cell and the second snlall cell on the macro cell, 5 a judgment unit that, in a case in which one of the first small cell and the second small cell exerts interference exceeding an allowed level on the other, juJgcs whc.iicr :Iii: il;;cr~erci;cc is i i i i i J i r ~ ~ i ; i ; ; r ~ or bi(-j:i.<;Liiuiitl!, iiii:j a control unit that controls the interference between the first small cell and the second snlall cell with a technique t h t differs according to a judgment 10 result by the judgment unit.