COMMUNICATION CONTROL DEVICE, COMMUNICATION CONTROL METHOD, AND TERMINAL DEVICE
Technical Field [0001]
The present disclosure relates to a communication control device, a communication control method, and a terminal device.
Background Art [0002]
At present, 4G radio communication systems have been standardized by the Third Generation Partnership Project (3GPP). In 4G, technologies such as carrier aggregation, relay, and Multi-User Multiple-Input Multiple-Output (MU-MIMO) have been noticed. [0003]
In particular, carrier aggregation is a technology capable of collectively handling, for example, five frequency bands with a bandwidth of 20 MHz to handle a bandwidth of 20 MHzx5=IOO MHz. According to carrier aggregation, an advance in the maximum throughput is expected. Various technologies related to such carrier aggregation have been investigated. [0004]
For example, Patent Literature 1 discloses a technology for suppressing deterioration in throughput by controlling assignment of a measurement gap for each component carrier (CC) based on a determination result of urgency of handover.
Citation List Patent Literature [0005]

Patent Literature 1: JP2011-120196A
Summary of Invention Technical Problem [0006]
On the other hand, in Release 11 of the 3GPP, new carrier types (NCTs) have been investigated as new component carriers apart from legacy CCs (existing CCs) capable of maintaining backward compatibility. Here, the NCTs are assumed to be new types of CCs as well as the types of CCs. Further, as the NCTs, an NCT (Synchronized New Carrier Type: SNCT) synchronized with the legacy CCs and an NCT (Unsynchronized New Carrier Type: UNCT) not synchronized with the legacy CCs have been investigated. [0007]
The SNCT is synchronized with any legacy CC. Therefore, when a user equipment (UE) establishes synchronization in one CC between the mutually synchronized SNCT and the legacy CC, a synchronization result of the UE in the one CC can be used for the other CC. That is, the UE does not have to establish separate synchronization with a synchronization signal (for example, a common reference signal (CRS)) in the other CC. [0008]
The UNCT is not synchronized with any legacy CC, but can be synchronized with different UNCTs. When the UE establishes synchronization in one UNCT among two or more mutually synchronized UNCTs, a synchronization result of the UE in the one UNC'f can be utilized for the diflerent CCs. That is, the UE does not have to establish separate synchronization with a synchronization signal in the other CCs. [0009]
However, in order for the UE to use the synchronization result of the UE in a certain CC for another CC, there is a concern of a large load being applied to the UE. [0010]

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For example, since a frequency band separate from the SNCT can be present in the legacy CC, the SNCT is not synchronized with all of the legacy CCs. Therefore, the UE verifies the synchronization regarding various conbinations between the SNCT and legacy CCs in order to use the synchronization result of the UE in the legacy CC for the SNCT. In this way, a large load may be applied to the UE. [0011]
For example, there is a possibility of the UNCT being synchronized with another UNCT, but not all of the UNCTs are necessarily synchronized. Therefore, the UE verifies the synchronization regarding various combinations between the UNCTs in order to use the synchronization result of the UE in a certain UNCT for another UNCT. In this way, a large load may be applied to the UE. [0012]
In particular, when a macro cell and a small cell partially or entirely overlapping with the macro cell are present, the number of combinations of the synchronizable CC is considerably large. Therefore, a larger load may be applied to the UE in order to verify the synchronization. [0013]
Originally, when the UE does not use a synchronization result of a UE in a certain CC for a different CC, it is necessary to establish synchronization with a synchronization signal in each CC. In this way, a large load may be applied to the UE. [0014]
Based on the above description, the inventors of the present specification conceived of supplying information indicating a synchronization relationship (that is, which CCs are mutually synclironized) between CCs to a UE. However, even when the information "indicating the synchronization relationship is reported to the UE, valuable radio resources in a macro cell may be consumed when a considerable amount of information is supplied by the macro cell. [0015]
Accordingly, it is desirable to provide a configuration in which consumption

of radio resources of a macro eel! can be suppressed while reducing a load in a UE in carrier aggregation when the macro cell and a small cell are deployed.
Solution to Problem [0016]
According to the present disclosure, there is provided a communication control device including: a communication control unit configured to control radio communication in a small cell partially or entirely overlapping with a macro cell; and an acquisition unit configured to acquire first synchronization relationship information indicating whicli frequency bands are mutually synchronized among a plurality of frequency bands used for the small cell. The first synchronization relationship information is supplied in the small cell by the communication control unit and is not supplied in the macro cell by a base station of the macro cell. [0017]
According to the present disclosure, there is provided a communication control method including: controlling radio communication in a small cell partially or entirely overlapping with a macro cell; and acquiring first synchronization relationship information indicating which frequency bands are mutually synchronized among a plurality of frequency bands used for the small cell. The fu'st synchronization relationship information is supplied in the small cell by a base station of the small cell and is not supplied in the macro cell by the base station of the macro cell. [0018]
According to the present disclosure, there is provided a communication control device including: a communication control unit configured to control radio communication in a macro cell partially or entirely overlapping with a small cell; and an acquisition unit configured to acquire synchronization relationship information indicating which frequency bands are mutually synchronized among a plurality of frequency bands. The connnunication control unit supplies the synchronization relationship information in the macro cell, the synchronization relationship information does not include first synchronization relationship information indicating

which frequency bands are mutually synchronized among a plurality of frequency bands used for the small cell, and the first synchronization relationship information is supplied by a base station of the small cell. [0019]
According to the present disclosure, there is provided a terminal device including: a radio communication unit configured to perform radio communication in a macro cell or a small cell partially or entirely overlapping with the macro cell, and an acquisition unit configured to acquire first synchronization relationship information indicating which frequency bands are mutually synchronized among a plurality of frequency bands used for the small cell from information supplied in the small cell by a base station of the small cell and configured not to acquire the first synchronization relationship information from information supplied in the macro cell by a base station of the macro cell.
Advantageous Effects of Invention [0020]
According to the present disclosure described above, it is possible to suppress consumption of radio resources of a macro cell while reducing a load in a UE in carrier aggregation when the macro cell and a small cell arc deployed.
Brief Description of Drawings [0021]
[FIG, 1] FIG. 1 is an explanatory diagram illustrating an example of a PCC of each UE.
[FIG. 2] FIG 2 is an explanatoiy diagram illustrating an example of a CRS transmitted in a CC on a downlink.
[FIG. 3] FIG. 3 is an explanatory diagram illustrating examples of NCTs. [FIG. 4] FIG. 4 is an explanatory diagram illustrating an example of a reduction in CRSs in a frequency direction.
[FIG. 5] FIG. 5 is an explanatory diagram illustrating an example of a reduction in CRSs in the time direction.

[FIG. 6] FIG. 6 is an explanatory diagram illustrating examples of three deployment
scenarios of a small cell.
[FIG 7] FIG 7 is an explanatory diagram illustrating characteristics of system
information and RRC signaling.
[FIG. 8] FIG 8 is an explanatory diagram illustrating time synchronization between
component carriers.
[FIG 9] FIG 9. is an explanatory diagram illustrating frequency synchronization
between component carriers.
[FIG. 10] FIG. 10 is an explanatoiy diagram illustrating an example of a schematic
configuration of a communication system according to an embodiment.
[FIG. 11] FIG. U is a block diagram illustrating an example of the configuration of a
pico eNodeB according to the embodiment.
[FIG. 12] FIG. 12 is an explanatory diagram illustrating examples of kinds of
suppliable synchronization relationship information.
[FIG. 13] FIG. 13 is an explanatory diagram illustrating examples of kinds of
synchronization relationship information supplied by a serving pico eNodeB.
[FIG. 14] FIG. 14 is a block diagram illustrating an example of the configuration of a
macro eNodeB according to the embodiment.
[FIG. 15] FIG. 15 is an explanatory diagram illustrating examples of kinds of
synchronization relationship information supplied by a serving macro eNodeB.
[FIG. 16] FIG. 16 is a block diagram illustrating an example of the configuration of a
UE according to the embodiment.
[FIG. 17] FIG. 17 is an explanatory diagram illustrating an example of a first
communication control process on the side of a pico eNodeB according to the
embodiment.
[FIG 18] FIG. 18 is an explanatory diagram illustrating an example of a second
communication control process on the side of the pico eNodeB according to the
embodiment.
[FIG. 19] FIG. 19 is an explanatory diagram illustrating an example of a
communication control process on the side of the macro cNodcB according to the
embodiment.

[FIG. 20] FIG. 20 is an explanatory diagram illustrating an example of a
communication control process on the side of a UE according to the embodiment.
[FIG. 21] FIG. 21 is an explanatory diagram illustrating examples of kinds of
synchronization relationship information supplied by a serving pico cNodeB
according to a first modification example of the embodiment.
[FIG. 22] FIG. 22 is an explanatory diagram illustrating examples of kinds of
synchronization relationship information supplied by a serving macro eNodeB
according to the first modification example of the embodiment.
[FIG. 23] FIG. 23 is an explanatory diagram illustrating examples of kinds of
suppliable synchronization relationship information according to a second
modification example of the embodiment.
[FIG. 24] FIG. 24 is an explanatory diagram illustrating examples of kinds of
synchronization relationship information supplied by a serving pico eNodeB
according to the second modification example of the embodiment.
[FIG 25] FIG. 25 is an explanatory diagram iHustrating examples of kinds of
synchronization relationship information supplied by a serving pico eNodeB
according to the second modification example of the embodiment.
[FIG. 26] FIG. 26 is an explanatory diagram illustrating an example of a first
comnuinication control process on the side of a pico eNodeB accordnig to a third
modification example of the embodiment.
[FIG. 27] FIG. 27 is an explanatory diagram illustrating an example of a second
communication control process on the side of the pico eNodeB according to the third
modification example of the embodiment.
[FIG. 28] FIG. 28 is an explanatory diagram illustrating an example of a
communication control process on the side of the macro eNodeB according to the
third modification example of the embodiment.
[FIG. 29] FIG. 29 is an explanatory diagram illustrating an example of a
communication control process on the side of a UB according to the third
modification example of the embodiment.
[FIG. 30] FIG. 30 is an explanatory diagram illustrating examples of kinds of
synchronization relationships when pico cells 11 are deployed as in a third scenario.

[FIG. 31] FIG. 31 is a block diagram illustrating a first example of a schematic
configuration of an eNodeB to which technology according to an embodiment of the
present disclosure may be applied.
[FIG 32] FIG. 32 is a block diagram illustrating a second example of a schematic
configuration of an eNodeB to which technology according to an embodiment of the
present disclosure may be applied.
[FIG 33] FIG. 33 is a block diagram illustrating an example of a schematic
configuration of a smartphone to which technology according to an embodiment of
the present disclosure may be applied.
[FIG. 34] FIG. 34 is a block diagram illustrating an example of a schematic
configuration of a car navigation device to which technology according to an
embodiment of the present disclosure may be applied.
Description of Embodiments [0022]
Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the appended drawings. Note that, in this specification and the appended drawings, structural elements that have substantially the same function and structure are denoted with the same reference numerals, and repeated explanation of these structural elements is omitted. [0023]
The description will be made in the following order.
1. Technology for radio communication in 3GPP
2. Technical problems according to embodiment of the present disclosure

2.1. Examination of synchronization between frequency bands
2.2. Technical problems
3. 'Schematic configuration of communication system according to
embodiment
4. Configuration of each device
4.1. Configuration of pico eNodeB
4.2. Configuration of macro eNodeB

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4.3. Configuration of UE
5. Flow of process
6. First modification example
7. Second modification example 5 8. Third modification example
9. Others
10. Application examples
11. Applications related to pico cNodeB and macro eNodcB
12. Applications related to UE 10 II. Conclusion
[0024]
«<1. Technology for radio communication in 3GPP»>
First, a technology for radio communication in the 3GPP will be described as a premise. 15 [0025]
(Carrier aggregation of Release 10)
- Component carrier
In carrier aggregation of Release 10, up to five component carriers (CCs) are bundled and used by a UE. Each CC is a bandwidth of up to 20 MHz. In 20 carrier aggregation, CCs continuing in a fiequency direction are used in some cases and CCs separated in the ft'cquency direction are used in some cases. In carrier aggregation, the CCs to be used can be set for each UE. [0026]
- Priinaiy CC and secondary CC
25 In carrier aggregation, one of the plurality of CCs used by the UE is a
special CC. The one special CC is referred to as a primary component carrier (PCC). Of the plurality of CCs, the remaining CCs are referred to as secondary component carriers (SCCs). The PCC can differ for each UE. This point will be described more specifically below with reference to FIG. 1.
30 [0027]
FIG. I is an explanatory diagram illustrating an example of the PCC of each

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UE. A UE 30A, a UE 30B, and five CCs 1 to 5 are illustrated in FIG I. In this example, the UE 30A uses two CCs, the CC I and the CC 2. The UE 30A uses the CC 2 as the PCC. On the other hand, the UE 30B uses two CCs, the CC 2 and the CC 4. The UE 30B uses the CC 4 as the PCC. In this way each UE can use a 5 different CC as the PCC. [0028]
. Since the PCC is the most important CC among the plurality of CCs, the CC for which communication quality is the stablest is preferable. Which CC is used as the PCC actually depends on the way in whicii they are installed.
10 [0029]
The CC with which a UE initially establishes connection is the PCC for the UE. The SCC is added to the PCC. That is, the PCC is a main frequency band and the SCC is an auxiliary frequency baiid. The SCC is changed by deleting the existing SCC and adding a new SCC. The PCC is changed in an inter-frequency
15 handover sequence of the related att. In carrier aggregation, a UE cannot use only the SCC, but necessarily uses one PCC. [0030]
The PCC is also referred to as a primary cell. The SCC is also referred to as a secondary cell.
20 [0031]
- Synchronization by UE in CRS
In carrier aggregation, a common reference signal (CRS) is transmitted in each CC. A UE establishes synchronization in each CC by the CRS. In the present specification, "synchronization (by the UE in the CC)" means that the UE
25 adjusts (for example, tracks synchronization) a timing and/or a frequency in reception of a signal so that a signal can be correctly received in the CC. 'fhc common reference signal is also referred to as a cell-specific reference signal. [0032] (NCT of Release 12)
30 In carrier aggregation, each CC has been assumed to be able to be used by a
legacy UE (that is, an existing UE) from the viewpoint of guarantee of backward

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compatibility. However, the definition of a CC that cannot be used by a legacy UE but is more efficient has started to be investigated. That is, definition of new CCs referred to as new carrier types (NCT) or additional carriers has started to be investigated. 5 [0033]
The ultimate motivation for the NCT is to reduce overhead of the CCs. Overhead is radio resources other than radio resources utilized to transmit user data. That is, overhead is radio resources utilized for control. When overhead increases, the radio resources that can be utilized to transmit user data may decrease.
10 Therefore, the increase in overhead is not preferable. One cause of overhead is a CRS present in each CC in a downlink. This point will be described more specifically below with reference to FIG. 2. [0034]
FIG. 2 is an explanatory diagram illustrating an example of a CRS
15 transmitted in a CC on a downlink. Several radio resource blocks (RBs) corresponding to the CCs of 20 MHz are illustrated in FIG 2. Each RB has a width of 12 subcarriers in a frequency direction and a width of 7 Orthogonal Frequency Division Multiplexing (OFDM) symbols in a time direction. The CRSs are transmitted in each RB. That is, the CRSs are transmitted in all of the RBs present
20 across the bandwidth of the CCs in the frequency direction and present for each slot in the time direction. Accordingly, the CRS is transmitted in each CC and each subframe. [0035]
One objective of the CRS is for a UE to establish synchronization. As the
25 synchronization, there is time synchronization (or timing synchronization) which is synchronization in the time direction and frequency synchronization which is synchronization in the frequency direction. Tlie UE can establish synchronization with high precision in the frequency direction and the time direction by the CRS. Further, the UE continues to establish synchronization by the CRS.
30 [0036]
Another objective of the CRS is that the UE properly demodulates a

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downlink signal. The UE demodulates different received signals based on the
phases of the CRSs.
[0037]
The common reference signal (CRS) is the most fundamental reference 5 signal (RS) introduced in Release 8. On the other hand, at present, there is an intermittently transmitted RS such as a channel state information-refeienee signal (CSI-RS). The RS is used to demodulate a downlink signal. Accordingly, a current objective of the CRS is mainly that the UE can establish synchronization. Therefore, as far as the UE can establish synchronization, the interval at which the
10 CRS is transmitted can be decreased. [0038]
(Reduction in CRSs investigated in NTC in Release 11) -Kinds of NCTs
As the NCTs investigated in Release II, there are broadly two kinds of
15 NCTs. [0039]
One of the two kinds of NCTs is an NCT that is synchronized with a legacy CC (that is, an existing CC). When the UE establishes synchronization in a legacy CC, the UE can utilize a synchronization result of the UE in the legacy CC for the
20 NCT synchronized with the legacy CC. Such an NCT is referred to as a synchronized NCT (hereinafter referred to as an "SNCT"). Further, in the present specification, "utilize the synchronization result (of the UE in the CC) (for a different CC)" means that a reception timing and a reception frequency in the different CC are acquired from a reception timing and a reception frequency in the CC.
25 [0040]
The other of the two kinds of NCTs is an NCT that is not synclironized with a legacy CC. The UE necessarily establishes synchronization in an NCT. Such an NCT is referred to as an unsynchronized NCT (hereinafter referred to as an "UNCT"). Since the synchronization process is necessary in the UNCT, the CRSs are
30 transmitted in the UNCT. [0041]

SP352097WO00 3/104
As described above, as the NCT, there are the SNCT and the UNCT.
Hereinafter, specific examples of the SNCT and the UNCT will be described with
reference to FIG. 3.
[0042]
5 FIG. 3 is an explanatory diagram illustrating an example of the NCT. Five
CCs 40 are illustrated in FIG 3. Of the five CCs 40, a CC 40A and a CC 40B arc
legacy CCs. In this example, the CC 40A and the CC 40B are mutually
synchronized. A CC 40C, a CC 40D, and a CC 40E are the NCTs. More
specifically, the CC 40C is an SNCT that is synchronized with both of the CC 40A 10 and the CC 40B which are the legacy CCs. The CC 40D and the CC 40E are
UNCTs that are synchronized with neither the CC 40A nor the CC 40B. In this
example, the CC 40D and the CC 40E are not mutually synchronized.
[0043]
- Reduction in CRSs in unsynchronized NCT
15 Since the CRS transmitted in the legacy CC is transmitted not only to
establish synchronization of the UE but also to demodulate a received signal, the
CRS is redundant. On the other hand, since the CIS-RS is standardized as an RS
for demodulation in releases after Release 10, it is possible to reduce the CRSs.
Accordingly, an extent to which CRSs can be reduced while enabling the UE to 20 continuously establish synchronization has been investigated. In particular, a
reduction in the CRSs in the frequency direction and a reduction in the CRSs in tlie
time direction have been investigated as the reduction in the CRSs of the
unsynchronized NCT (that is, the UNCT).
[0044]
25 As the reduction in the CRSs in the frequency direction, for example, the
RBs in which the CRSs are transmitted is reduced to 6 RBs, 25 RBs, or 50 RBs.
Hereinafter, this point will be described specifically with reference to FIG. 4.
[0045]
FIG 4 is an explanatory diagi'am illustrating an example of a reduction in 30 the CRSs in the frequency direction. A case in wliich the RBs in which the CRSs
are transmitted arc reduced to 6 RBs in the frequency direction and a case in which

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the RBs in which the CRSs are transmitted are reduced to 25 RBs in the frequency
direction are illustrated in FIG. 4. In this way, not all of the CRSs in the RBs in the
frequency direction are transmitted, but the CRSs in a limited number of the RBs are
transmitted. 5 [0046]
On the other hand, as the reduction in the CRSs in the time direction, for
example, a transmission period of the CRSs is considered to be 5 ms or 10 ms. This
point will be described specifically with reference to FIG. 5.
[0047]
10 FIG. 5 is an explanatory diagram illustrating an example of a reduction of
the CRSs in the time direction. A case in which the transmission period of the CRS
is 5 ms and a case in which the transmission period of the CRS is 10 ms are
illustrated in FIG. 5. In this way, not all of the CRSs of the slots or the subframes in
the time direction are transmitted, but the CRSs of a limited number of the subframes 15 are transmitted.
[0048]
As described above, a method of combining the reductions in the CRSs in
the fiequency direction and the reductions in the CRSs in the time direction has been
investigated. As an evaluation of whether the UE establishes synchronization, 20 whether accuracy of about 500 Hz is maintained in an environment of an SNR of-8
dB was evaluated. As a result, in the environment of an SNR of -8 dB, it is
necessary to transmit the CRS in 25 RBs every 5 ms.
[0049]
- Reduction in CRSs in synchronized NCT
25 On the other hand, since the synchronized NCT (SNCT) is synchronized
with the legacy CC, the existing CRSs can be basically deleted in the SNCT.
[0050]
(Synchronization monitoring procedure)
The UE monitors whether the UE establishes synchronization based on a 30 block error rate (BLER) of a physical downlink control channel (PDCCH). In other
words, the UE detects synchronization deviation of the UE based on the BLER of the

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PDCCH. For example, when the BLER of the PDCCH is equal to or greater than
10%, the UE detects the synchronization deviation.
[0051]
When the synchronization deviation is detected a predetermined number of 5 times, a timer staits. Then, when a period of time of the timer expires, radio link failure (RLF) is recognized. When the RLF is recognized, the UE stops all of the transmission within 40 nis from the recognition of the RLF in order to avoid interference with another UE. Thereafter, the UE performs a procedure of RRC reestablishment including cell selection and random access.
10 [0052]
The UE performs the above-described synchronization monitoring on the PCC, but does not perform the synchronization monitoring on the SCC. The UE deactivates the SCC when the PDCCH is not detected in the SCC. [0053]
15 (NCT of Release 12)
NCT of Release 12 is a study item (SI) that was approved in September 2012 as RP-12I415 at the 3GPP RAN #57 Plenaty meeting. This SI is divided into phase 1 and phase 2. In phase 1, enhancement of NCT of Release 11 is scheduled to be investigated. In phase 2, the enhancement is scheduled to be investigated in
20 consideration of scenarios of small cells. Specific examples of small cells include a pico cell, a nano cell, and a femto cell. In the present specification, the description will be made exemplifying a pico eel! as the small cell. [0054]
As the scenarios of a small cell, three deployment scenarios of a small cell
25 are considered at present in 3GPP. In a first deployment scenario (that is, Deployment Scenario 1), a small cell is entirely overlapping with a macro cell. In a second deployment scenario (that is, Deployment Scenario 2), a small cell is paitially overlapping with a macro cell. In a third deployment scenario (that is. Deployment Scenario 3), a small cell is not overlapping with a macro cell. That is, there is no
30 macro cell near the small cell and only the small cell is operated. Hereinafter, specific examples of the deployment scenarios will be described with reference to

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FIG. 6.
[0055]
FIG. 6 is an explanatory diagram illustrating examples of three deployment
scenarios of a small cell. Referring to FIG. 6, three pico cells IIA, I IB, and IIC 5 and a macro cell 21 are illustrated. Pico eNodeBs 10 which are base stations of the
pico cells 11 and a macro eNodeB 20 which is a base station of the macro cell 21 are
also illustrated. First, the pico cell llA is entirely overlapping with the macro cell
21, the pico cell I IB is partially overlapping with the macro cell 21, and the pico cell
1IC is not overlapping with the macro cell 21. That is, the deployment of the pico 10 cell llA corresponds to the first deployment scenario, the deployment of the pico cell
I IB corresponds to the second deployment scenario, and the deployinent of the pico
cell lie corresponds to the third deployment scenario. In the example, radio
communication is performed using a frequency band Fl in the macro cell 21.
Further, radio communication is performed using a frequency band F2 in the pico 15 cell 11.
[0056]
(Supply methods for control information to UE)
The eNodeB uses, for example, system information or radio resource
control (RRC) signaling when the eNodeB supplies control infonnation to the UE. 20 Hereinafter, characteristics of t\vo supply methods will be described with reference to
FIG. 7.
[0057]
FIG. 7 is an cxplanatoiy diagram illustrating characteristics of system
information and RRC signaling. Referring to FIG. 7, a UE state necessary for the 25 eNodeB to supply the control information to the UE, a supply target UE (and
supplied information), and a suppliable information amount are illustrated for the
system information and the RRC signaling.
[0058]
First, in order for the eNodeB to supply the control information with the 30 system information, the UE may be in one of RRCConnected (that is, a connection
state) and RRC_Idle (that is, an idle state). On the other hand, in order for the

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eNodeB to supply the control information with the RRC signaling, the UE has to be
in RRCConnected (that is, the connection state).
[0059]
Second, the control information is supplied with the system information to 5 ail of the UEs rather than an individual UE. That is, the control information
supplied with the system information can be said to be information common to the
UEs. On the .other hand, the control information is basically supplied with the RRC
signaling to the individual UE. That is, the control information supplied with the
RRC signaling can be said to be basically the control information of the separate UE. 10 However, by transmitting the control information common to other UEs with the
RRC signaling, the common information can also be supplied to the UEs with the
RRC signaling.
[0060]
Third, the system information includes restricted control information and is 15 transmitted using restricted radio resources. Therefore, an information amount of
control information supplied with the system information is small. On the other
hand, the RRC signaling is transmitted with a Physical Downlink Shared CHannel
(PDSCH) relatively freely. Therefore, an information amount of control
information supplied with the RRC signaling is large. 20 [0061]
<2. Technical problems according to embodiment of the present disclosure>
Next, technical problems in an embodiment of the present disclosure will be
described.
[0062] 25 <2.1 Examination ofsynchronization between frequency bands>
First, examination of synchronization between frequency bands will be
described.
[0063]
(Synchronization between frequency bands)
30 Here, the synchronization between frequency bands will be described more
specifically. As the synchronization between the frequency bands, there arc

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synchronization in a time direction (hereinafter referred to as "time synchronization") and synchronization in a frequency direction (hereinafter referred to as "frequency synchronization"). Hereinafter, specific examples of this point will be described with reference to FIGS. 8 and 9. 5 [0064]
FIG. 8 is an explanatoiy diagram illustrating tiie time synchronization between component carriers. Referring to FIG. 8, reception timings of the CC 1 and the CC 2 are illustrated. For example, as in the example illustrated in FIG. 8, deviation can occur in the time direction between the reception timing of a signal
10 with the CC I in the UE and the reception timing with the CC 2 in the UE. For example, when the deviation in the time direction is less than a guard interval length of the OFDM, the CC 1 and the CC 2 can be considered to be mutually synchronized in the time direction. [0065]
15 FIG. 9 is an explanatoiy diagram illustrating frequency synchrotiization
bet\veen component carriers. Refening to FIG 9, the frequency band of the CC 1 and the frequency band of the CC 2 are illustrated. A center frequency of the CC 1 and a center frequency of the CC 2 are also illustrated. The center frequency of the CC I is separated from the center frequency of the CC 2 by a predetermined
20 frequency width. However, in practice, for example, deviation can occur in the frequency direction between the center frequency of the CC 2 and a frequency separated from the center frequency of the CC 1 by the predetermined frequency width. For example, when the deviation in the frequency direction is within a predetermined frequency width (for example, 500 Hz in LTE), the CC I and the CC
25 2 can be considered to be mutually synchronized in the frequency direction. [0066]
As described above, the synchronization between the frequency bands includes the time synchronization and the frequency synchronization. Therefore, there are tlie following four cases of the synchronization between the frequency
30 bands:
Case 1: both the time synchronization and the frequency synchronization are

SP352097WO00 '9/i04
achieved;
Case 2: the time synchronization is achieved, but the frequency synchronization is not achieved;
Case 3: the time synchronization is not achieved, but the frequency 5 synchronization is achieved; and
Case 4: neither the time synchronization nor the frequency synchronization is achieved. [0067]
In genera!, the mutually synchronized frequency bands are the frequency 10 bands corresponding to Case 1. However, the frequency bands corresponding to Case 2 or Case 3 may be considered to be the mutually synchronized frequency bands (in the time direction or the frequency direction). [0068]
(Synchronization on eNodeB side and synchronization on UE side)
15 From a different viewpoint, as the synchronization between the frequency
bands, there are synchronization on an eNodeB side (that is, a network side) and synchronization in a UE. Further, even when the time synchronization and the frequency synchronization are achieved for two CCs on the eNodeB side, it is not clear that the time synchronization and the frequency synchronization are achieved 20 on the UE side when the UE receives signals in the two CCs. [0069]
For example, when the CC 1 and the CC 2 are separated in the frequency direction, a propagation path of the CC 1 and a propagation path of the CC 2 arc diftfereiU. As a result, arrival times of the signals may be different. In this case, 25 the time synchronization is not achieved. [0070]
For example, a radio wave of the CC 1 and a radio wave of the CC 2 can
arrive at the UE from different directions. In this case, when the UE moves in the
arrival direction of the radio wave of the CC 1, the frequency of the CC I transitions
30 from a frequency f to a frequency f+Af by the Doppler eflect. Further, when the UE
moves in a direction opposite to the arrival direction of the radio wave of the CC 2,

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the frequency band of the CC 2 transitions from a frequency f to a frequency f-Af
due to the Doppler effect. In this way, the frequency synchronization is not
achieved due to the Doppler effect.
[0071]
5 As described above, since the time synchronization and the frequency
synchronization may not be achieved, it is not clear that the two CCs are mutually synchronized on the UE. side even if the two CCs are synchronized on the network side. [0072]
10 <2.2 Technical problems>
Next, technical problems will be described. [0073] - Utilization of Synchronization result
In Release 11 of 3GPP, as described above, NCTs have been investigated as
15 new component carriers apart from legacy CCs (existing CCs) capable of maintaining backward compatibility. Here, the NCTs are assumed to be new types of CCs and the CCs of the types. Further, an NCT (SNCT) synchronized with the legacy CC and an NCT (UNCT) not synchronized with the legacy CC have been investigated as the NCTs.
20 [0074]
Because the SNCT is synchronized with any legacy CC, when a UE establishes synchronization in one CC between the mutually synchronized SNCT and legacy CC, a synchronization result of the UE in the one CC can be utilized for the other CC. That is, the UE may not establish separate synchronization with a
25 synchronization signal in the other CC. [0075]
The "UNCT is not synchronized with any legacy CC, but can be synchronized with different UNCTs. When the UE establishes synchronization in one CC among two or more mutually synchronized UNCTs, a synchronization result
30 of the UE in the one CC can be utilized for the different CCs. That is, the UE does not have to establish separate synchronization witii a synchronization signal in the

SP352097WO00 21/104
other CCs. [0076]
- Load for use of synchronization result
However, in order for the UE to use the synchronization result of the UE in 5 a certain CC for another CC, there is a concern of a large load being applied to the UE. [0077]
For example, since a frequency band separate from the SNCT can be present in the legacy CC, the SNCT is not synchronized with all of the legacy CCs.
10 Therefore, tlie UE verifies the synchronization regarding various combinations between the SNCT and legacy CCs in order to use the synchronization result of the UE in the legacy CC for the SNCT. In this way, a large load may be applied to the UE. [0078]
15 For example, there is a possibility of the UNCT being synchronized with
another UNCT, but not all of the UNCTs are necessarily synchronized. Therefore, the UE verifies the synchronization regarding various combinations between the UNCTs in order to use the synchronization result of the UE in a certain UNCT for another UNCT. In this way, a large load may be applied to the UE.
20 [0079]
In particular, when a macro cell and a small cell partially or entirely overlapping with the macro cell are present, the number of combinations of the synchronizable CC is considerably large. Therefore, a larger load may be applied to the UE in order to verify the synchronization.
25 [0080]
Originally, when the UE does not use a synchronization resuh of a UE in a certain CC for a different CC, it is necessary to establish synchronization with a synchronization signal in each CC. In this way, a large load may be applied to the UE.
30 [0081]
- Supply of information indicating synchronization relationship

SP352097WO00 22/104
Based on the above description, the inventors of the present specification
conceived of supplying information indicating a synchronization relationship (that is,
which CCs are mutually synchronized) between CCs to a UE.
[0082]
5 As described above, even when two CCs are mutualiy synchronized on the
network side, it is not clear that the two CCs are mutually synchronized on the UE
side. Therefore, even when the UE comprehends the synchronization relationship,
the UE actually verifies the synchronization. Nonetheless, when the UE
comprehends the synchronization relationship (in other words, candidates of pairs of 10 synchronized CCs), it is possible to reduce resources of time and calculation
consumed to verity the synchronization. Therefore, it is useful to provide
information indicating the synchronization relationship to the UE.
[0083]
However, even when the information indicating the synchronization 15 relationship is reported to the UE, valuable radio resources in a macro cell may be
consumed when a considerable amount of information is supplied by the macro cell.
[0084]
Accordingly, an embodiment of the present disclosure makes it possible to
suppress consumption of radio resources of a macro cell while reducing a load in a 20 UE in carrier aggregation when the macro cell and a small cell are deployed.
[0085]
«3. Schematic configuration of communication system according to embodiment» Next, a schematic configuration of a communication system according to an
embodiment of the present disclosure will be described with reference to FIG. 10. 25 FIG. 10 is an explanatory diagram illustrating an example of the schematic
configuration of a communication system I according to the embodiment.
Referring to FIG. 1, the communication system 1 includes pico eNodeBs 100, a
macro eNodeB 200, and a UE 300. For example, the communication system I is a
system that conforms to LTB-Advanced. 30 [0086]
(Pico eNodeB 100)

SP352097WO00
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The pico cNodeB 100 performs radio communication with the UE 300
located in the pico cell 11 partially or entirely overlapping with the macro cell 21.
The pico cNodeB 100 performs the radio communication using a plurality of
component carriers (CCs). 5 [0087]
For example, the plurality of same CCs are used between different pico cells
11 (different pico eNodcBs 100). Specifically, for example, the pico eNodeB lOOA
and the pico eNodeB lOOB perform radio communication using the plurality of same
CCs. 10 [0088]
The pico eNodeB 100 can simultaneously use the plurality of CCs for radio
communication with one UE 300. That is, the pico eNodeB 100 supports the carrier
aggregation.
[0089]
15 For example, the plurality of CCs used in the pico cells U include one or
more CCs with which the CRS is not transmitted in at least one subframe among
subfranies which are units of times in the radio communication. More specifically,
for example, the plurality of CCs include at least one NCT.
[0090]
20 In the embodiment, the pico cells 11 are deployed as in the first deployment
scenario (that is, Deployment Scenario i) or the second deployment scenario (that is,
Deployment Scenario 2).
[0091]
(Macro cNodeB 200)
25 Ihc macro eNodeB 200 performs radio communication with the UE 300
located in the macro ceil 21. The macro eNodeB 200 performs the radio
communication using one or more CCs. For example, each of the one or more CCs
is the CC different from any of the plurality of CCs used in the pico cells li. For
example, the one or more CCs are a plurality of CCs. That is, the macro eNodeB 30 200 also performs radio communication using the plurality of CCs.
[0092]

SP352097WO00 24/104
For example, the plurality of same CCs are used between different macro cells 21 (different macro eNodeBs 200). Specifically, for example, the macro eNodeBs 200 in two mutually adjacent macro cells 21 perform radio communication using the plurality of same CCs. 5 [0093]
For example, the macro cNodeB 200 can simultaneously use a plurality of
CCs for radio communication with one UE 300. That is, the macro eNodcB 200
supports the carrier aggregation.
[0094]
10 For example, the plurality of CCs used in the macro cells 21 include one or
more CCs with which the CRS is not transmitted in at least one subframe among subframes which are units of times in the radio communication. More specifically, for example, the plurality of CCs include at least one NCT. [0095] 15 (UE 300)
The UE 300 performs radio communication with the pico cNodeB 100 in
the pico cell II. The UE 300 performs radio communication with the macro
cNodeB 200 in the macro cell 21.
[0096]
20 The UE 300 can simultaneously use a plurality of CCs for the radio
communication. Specifically, for example, the UE 300 can simultaneously use the plurality of CCs to perform the radio communication with the pico eNodeB 100 or the macro eNodeB 200. That is, the UE 300 supports the carrier aggregation. [0097] 25 «4. Configuration of each device»
Next, the configuration of each device included in the communication system "1 according to the embodiment of the present disclosure will be described with reference to FIGS. 11 to 16. [0098] 30 <4.i. Configuration of pico eNodeB>
First, the configuration of the pico eNodeB 100 according to the

SP352097WO00 25/104
embodiment will be described with reference to FIGS. 1 to 13. FIG. 11 is a block
diagram illustrating an example of the configuration of the pico eNodeB 100
according to the embodiment. Referring to FIG. II, the pico eNodeB 100 includes
an antenna unit 110, a radio communication unit 120, a network communication unit 5 130, a storage unit 140, and a control unit 150.
[0099]
(Antenna unit 110)
The antenna unit HO receives a radio signal and outputs the received radio
signal to the radio communication unit 120. The antenna unit HO transmits a 10 transmission signal output by the radio communication unit 120.
[0100]
(Radio communication unit 120)
The radio communication unit 120 performs the radio communication with
the UE 300 located in the pico cell 11. For example, the radio communication unit 15 120 performs the radio communication simultaneously using the plurality of CCs.
For example, the plurality of CCs are frequency bands different from the CCs used in
the macro cell 21. For example, the plurality of CCs include one or more NCTs.
[0101]
For example, the radio communication unit 120 can perform the radio 20 communication with one UE 300 simultaneously using the plurality of CCs. That is,
the pico cNodeB 100 supports carrier aggregation.
[0102]
(Network communication unit 130)
The network communication unit 130 communicates with another 25 communication node. For example, the network communication unit 130
communicates whh the macro eNodeB 200, another pico eNodcB 100, a mobility
management entify (MME), or the like.
[0103]
(Storage unit 140)
30 I1ic storage unit 140 stores a program and data for an operation of the pico
eNodeB 100.

SP352097WO00 26/104
[0104]
For example, the storage unit 140 stores the synchi'onization relationship information indicating which CCs are mutually synchronized among the plurality of CCs used for the radio communication. 5 [0105]
(Control unit 150)
The control unit 150 supplies various ftinctions of the pico eNodeB 100. [0106]
The control unit 150 includes a synchronization relationship information 10 acquisition unit 151 and a communication control unit 153. [0107] (Synchronization relationship information acquisition unit 151)
The synchronization relationship information acquisition unit 151 acquires synchronization relationship information indicating wiiich CCs are mutually 15 synchronized among the pluraMty of CCs (that is, a synchronization relationship between the CCs). [0108] - Kinds of synchronization relationship information which can be supplied to UE
First, kinds of synchronization relationship information which can be 20 supplied by the serving pico cNodeB lOOA or the serving macro eNodeB 200 in the certain UE 300 in the communication system 1 will be described with reference to FIG. 12. [0109]
FIG. 12 is an explanatory diagram illustrating examples of kinds of 25 suppliable synchronization relationship information. Referring to FIG. 12, the pico eNodeBs 100, the pico cells 11, the macro eNodeB 200, and the macro cell 21 are illustrated as iii FIG. 10. In this example, the UE 300 is located in the pico cell 11 A, the pico cell llA is a serving pico cell for the UE 300, and the macro cell 21 is a serving macro cell for the UE 300. In FIG 12, two CCs (CC I and CC 2) used for 30 the macro cell 21 and two CCs (CC 3 and CC 4) used for each pico cell 11 are illustrated. For example, in this way, difierent CCs are used between the macro cell

SP352097WO00 27/104
21 and the pico cells 11 and the same CCs are used between the pico cells 11.
[0110]
In the deployment of these cells, for example, information indicating the
following kinds of synchronization relationships (SR) can be supplied by the pico 5 eNodcB lOOA or the macro eNodeB 200:
SRI: a synchronization relationship between the CCs of the serving macro
cell 21;
SR2: a synchronization relationship between the CCs of the serving macro
cell 21 and the CCs of the serving pico cell IIA;
10 SR3: a synchronization relationship between the CCs of the serving macro
cell 21 and the CCs of the other pico cell 1 IB overlapping with the serving macro
cell 21;
SR4: a synchronization relationship between the CCs of the serving pico
cell IIA; and
15 SR5: a synchronization relationship between the CCs IIA of the serving
pico cell and the CCs of the other pico cell IIB overlapping with the serving macro
cell 21.
[0111]
-Acquisition of synchronization relationship information 20 - - SR4
First, in particular, in the embodiment, the synchronization relationship
information acquisition unit 151 of the pico eNodeB lOOA acquires the
synchronization relationship information indicating which CCs are mutually
synchronized among the plurality of CCs used for the pico cell IIA. 'fhat is, the 25 synchronization relationship information acquisition unit 151 acquires the
synchronization relationship information (hereinafter referred to as "SR4
information") indicating the SR4 among the synchronization relationships illustrated
in FIG. 12.
[0112]
30 More specifically, for example, the synchronization relationship information
acquisition unit 151 of the pico eNodeB 1OOA acquires the synchronization

SP352097WO00 28/104
relationship information (that is, the SR4 information) indicating which CCs are niutually synchronized between the CC 3 and the CC 4 of the pico cell 11 A. For example, when the CC 3 and the CC 4 of the pico cell IIA are mutually synchronized, the SR4 information indicates that the CC 3 and the CC 4 of the pico 5 cell llA are mutually synchronized. [0113] - - SR5
Second, for example, the synchronization relationship information acquisition unit 151 of the pico eNodeB lOOA acquires the synchronization
10 relationship information indicating which CC of the plurality of CCs used for the pico cell 11A is synchronized with which CC of one or more CCs used for different cells other than the macro cell 21 and the pico cell 11 A. [0114]
For example, the different cells include the different pico cell IIB partially
15 or entirely overlapping with the macro cell 21. That is, the synchronization relationship information acquisition unit 151 acquires synchronization relationship information (hereinafter referred to as "SR5 information") indicating the SR5 among the synchronization relationships illustrated in FIG. 12. [0115]
20 More specifically, for example, the synchronization relationship information
acquisition unit 151 of the pico eNodeB lOOA acquires the synchronization relationship information (that is, the SR5 information) indicating which CC of the CC 3 and the CC 4 of the pico cell 1 lA is synchronized with which CC of the CC 3 and the CC 4 of the pico cell I IB. For example, when theCC 3 of the pico cell 11A
25 and the CC 4 of the pico cell IIB are mutually synchronized, the SR5 information indicates that the CC 3 of the pico cell llA and the CC 4 of the pico cell IIB are mutually synchronized. Further, when the CC 4 of the pico cell I lA and the CC 3 of the pico cell IIB are mutually synchronized, the SR5 information indicates that the CC 3 of the pico cell llA and the CC 3 of the pico cell IIB are mutually
30 synchronized. [0116]

SP352097WO00 29/104
For example, as described above, the synchronization relationship information acquisition unit 151 acquires the SR4 information and the SR5 information as the synchronization relationship information. The SR4 information and the SR5 information are stored in the storage unit 140, and the synchronization 5 relationship information acquisition unit 151 acquires the SR4 information and the SR5 information from the storage unit 140. [0117] (Communication control unit 153)
The communication control unit 153 controls the radio communication in 10 the pico cell 11. For example, the communication control unit 153 supplies control information to the UE 300 located in the pico cell U. [0118] - Supply of synchronization relationship information
In particular, in the embodiment, the communication control unit 153 15 supplies the synchronization relationship information indicating the synchronization relationship bet^veen the plurality of CCs in the pico cell II. In other words, the comnuinieation control unit 153 supplies the synchronization relationship information to the UE 300 located in the pico cell 11. [0119] 20 - - SR4
First, the communication control unit 153 of the pico cNodeB lOOA supplies, in the pico cell IIA, the synchronization relationship information (that is, the SR4 information) indicating which CCs are mutually synchronized among the plurality of CCs used for the pico cell 11 A. 25 [0120]
The SR4 information is not supplied in the niaero cell 21 by the macro eNodeB 200. [0121]
The supply of the SR4 information results in a reduction in a load of the UB
30 300 in the carrier aggregation when the macro cell 21 and the pico ceiis 11 are
deployed. That is, when the SR4 information is not supplied to the UE 300, the UE

SP352097WO00 30/104
300 can separately verify all of the synchronization relationships between the CCs used for the pico cell 11. Conversely, when the SR4 information is supplied to the UE 300, the UE 300 may verify only the restricted synchronization relationships. For this reason, the supply of the SR4 information can result in the reduction in the 5 load oftheUE 300. [0122]
The SR4 information is not supplied by the macro eNodeB 200 but is supplied by the pico eNodeB 100. Thus, radio resources of the macro ceU 21 are not used to supply the SR4 information. That is, the supply of the SR4 information
10 by the pico eNodeB 100 can result in suppression of consumption of the radio resources of the macro cell 21. [0123] --SR5
Second, for example, the communication control unit 153 of the pico
15 eNodeB lOOA supplies, in the pico cell 11, the synchronization relationship information indicating which CC of the plurality of CCs used for the pico cell 1 lA is synchronized with which CC of one or more CCs used for different cells other than the macro eell 21 and the pico cell I lA. [0124]
20 For example, the different cells are different pico cells II partially or
entirely overlapping with the macro ccH 21. For example, the plurality of CCs are used for the different pico cells II. That is, the communication control unit 153 of the pico cNodeB lOOA supplies the synchronization relationship information (that is, the "SR5 information") indicating which CC of the plurality of CCs used for the pico
25 cell 11A is synchronized with which CC of the plurality of CCs used for the pico cell IIB. [0125]
For example, the SR5 information is not supplied in the macro cell 21 by the macro eNodeB 200.
30 [0126]
The supply of the SR5 information can result in the reduction in the load of

SP352097WO00
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the UE 300 in the carrier aggregation when the macro cell 21 and the pico cell 11 are deployed. For example, when two pico cells 11 are adjacent and the UE 300 is located near the boundary of the two pico cells, the UE 300 can also perform the radio communication simultaneously using the CC of one pico cell 11 and the CC of 5 the other pico cell 11. For example, even when t\vo pieo cells II overlap and separate CCs are used between the two pico cells 11, the UE 300 can also peiform the radio communication simultaneously using the CC of one pico cell 11 and the CC of the other pico cell 11. In this case, when the SR5 information is not supplied to the UE 300, the UE 300 can separately verify all of the synchronization relationships
10 bet\veen the CCs used for one pico cell 11 and the CCs used for the other pico cell 11. Conversely, when the SR5 information is supplied to the UE 300, the UE 300 may verify only the restricted synchronization relationships. For this reason, the supply of the SR5 information can result in the reduction in the load of the UE 300. [0127]
15 The SR5 information is not supplied by the macro eNodeB 200 but is
supplied by the pico eNodeB 100. Thus, radio resources of the macro cell 21 are not used to supply the SR5 information. That is, the supply of the SR5 information by the pico eNodeB 100 can result in suppression of consumption of the radio resources of the macro cell 21.
20 [0128]
--SRl,SR2,and SR3
On the other hand, for example, synchronization relationship information (hereinafter referred to as "macro SR information") indicating which CC of one or more different CCs used for the macro cell 21 is synchronized with which CC is
25 supplied in the macro cell 21 by the macro eNodeB 200. For example, the macro SR information is not supplied in the pico cell II by the pico eNodeB 100 (the communication control unit 153). [0129] - - SR2 and SR3
30 For example, the macro SR information indicates which CC of one or more
different CCs used for the macro cell 21 is synchronized with which CC of the

SP352097WO00 32/104
plurality of CCs used for the pico cell 11. That is, the macro SR information
includes synchronization relationship information (hereinafter referred to as "SR2
information") indicating the SR2 among the synchronization relationships illustrated
in FIG. 12. In other words, the SR2 information is supplied in the macro cell 21 by 5 the macro eNodeB 200 and is not supplied in the pico cell HA by the pico cell
eNodeB lOOA.
[0130]
As in the SR2 information, synchronization relationship information
(hereinafter referred to as "SR3 information") indicating the SR3 can also be 10 supplied in the macro cell 21 by the macro eNodeB 200. The SR3 information is
not supplied in the pico cell 11A by the pico eNodeB lOOA.
[0131]
--SR1
For example, the one or more different CCs used for the macro cell 21 15 include two or more CCs, and the macro SR information indicates which CCs are
mutually synchronized among the one or more different CCs. That is, the macro
SR information includes synchronization relationship information (hereinafter
referred to as "SRI information") indicating the SRI among the synchronization
relationships illustrated in FIG. 12. That is, the SRI information is supplied in the 20 macro cell 21 by the macro eNodeB 200 and is not supplied in the pico cell 11 by the
pico eNodeB 100.
[0132]
As described above, the various kinds of synchronization relationship
information are supplied in the pico cells 11 or not supplied. Hereinafter, the kinds 25 of synchronization relationship information supplied by the serving pico eNodeB
lOOA and the kinds of synchronization relationship information that are not supplied
will be confirmed with reference to FIG 13.
[0133]
FIG 13 is an explanatory diagram illustrating examples of kinds of 30 synchronization relationship information supplied by a serving pico eNodeB lOOA.
As illustrated in FIG. 13, for example, the serving pico eNodeB lOOA (the

SP352097WO00 33/i04
communication control unit 153) supplies the SR4 information and the SR5 information in the pico cell IIA. Conversely, serving pico cNodeB lOOA (the communication control unit 153) does not supply the SRI information, the SR2 information, and the SR3 information in the pico cell 11 A. 5 [0134]
- Supply method for synchronization relationship information
As a specific supply method, for example, the communication control unit 153 supplies the synchronization relationship information via the radio communication unit 120 using the system information. More specifically, for
10 example, the communication control unit 153 generates the system information including the SR4 information and the SR5 information and causes the radio communication unit 120 to transmit the system information in the pico cell 11. The coiumunication control unit 153 may transmit the SR4 information and the SR5 information to the UE using the RRC signaling in the pico cell 11.
15 [0135]
- Supply order of synchronization relationship information
For example, the communication control unit 153 supplies tAvo or more kinds of synchronization relationship information in an order according to importance of the kinds of information. The two or more kinds of synchronization
20 relationship information include the SR4 information. Futther, the two or more kinds of synchronization relationship information include the SR5 information. [0136]
For example, the SR4 information and the SR5 information are transmitted using the system information. In this case, the communication control unit 153
25 generates the system information so that the SR4 information and the SR5 information are lined up in the system information in the order according to the impoitance of the SR4 information and the impoitance of the SR5 information. For example, (he impoitance of the SR4 information is higher than the importance of the SR5 information. In this case, the communication control unit 153 generates the
30 system information so that the SR4 information and the SR5 information are lined up in this order. Then, the communication control unit 153 causes the radio

34/104

SP352097WO00

communication unit 120 to transmit the system information.
[0137]
The various kinds of synchronization relationship information are supplied
in the order according to the importance in this way. Thus, the UE 300 can verify 5 the synchronization relationships in order from the synchronization relationship with
the high importance. As a result, it is possible to reduce a process in which the UE
300 can establish the synchronization.
[0138J
The SR4 information and the SR5 information may be transmitted using the 10 RRC signaling. When the SR4 information and the SR5 information are
transmitted at the same time, as in the example of the system information, the SR4
information and the SR5 information may be lined up in the order according to the
importance in the transmitted information. On the other hand, when the SR4
information and the SR5 information are separately transmitted, the SR4 information 15 and the SR5 information may be supplied using the RRC signaling in the order
according to the importance of the SR4 information and the importance of the SR5
information.
[0139]
- Supply of supply spot information
20 For example, the communication control unit 153 supplies, in the pico cell
11, information (hereinafter referred to as "supply spot information") indicating a
spot between the macro cell 21 and the pico cell 11 where each of the two or more
kinds of synchronization relationship information is supplied.
[0140]
25 Specifically, for example, the communication control unit 153 supplies the
supply spot information indicating that the SR4 information and the SR5 information
are transmitted in the pico cell II and the SRI information, the SR2 information, and
the SR3 information are transmitted in the macro cell 21.
[0141]
30 As a specific supply method, for example, when the UE 300 is in
RRCConnected in the pico cell 11, the communication control unit 153 supplies the

SP352097WO00 35/104
supply spot information to the UE 300 via the radio communication unit 120 using
the RRC signaling. The supply spot information may be suppMcd usnig the system
information.
[0142]
5 When the supply spot information is supplied, the UE 300 can comprehend
where the UE 300 may acquire the various kinds of synchronization relationship
information between the macro cell 21 and the pico cell 11. Therefore, it is not
necessary for the UE 300 to search for the synchronization relationship information
in both of the macro ceil 21 and the pico ceil 11. For example, when the necessary 10 synchronization relationship information is supplied in one of the pico cell 11 and the
macro cell 21, the synchronization relationship information may be acquired only in
the one cell, and thus a process performed to acquire the synchronization relationship
information is reduced.
[0143] 15 <4.2. Configuration of macro eNodeB>
Next, the example of the configuration of the macro eNodeB 200 according
to the present embodiment will be described with reference to FIGS. 14 and 15.
FIG. 14 is a block diagram illustrating an example of the configuration of the macro
eNodeB 200 according to the present embodiment. Referring to FIG. 14, the macro 20 eNodeB 200 includes an antenna unit 210, a radio communication unit 220, a
network communication unit 230, a storage unit 240, and a control unit 250.
(Antenna unit 210)
The antenna unit 210 receives a radio signal and outputs the received radio
signal to the radio communication unit 220. The antenna unit 210 transmits the 25 transmitted signal output by the radio communication unit 220.
[0144]
(Radio communication unit 220)
The radio communication unit 220 performs the radio communication with
the UE 300 located in the macro cell 21. For example, the radio communication 30 unit 220 performs the radio communication simultaneously using the plurality of
CCs. For example, the plurality of CCs are fiequency bands different fi'oiii the CCs


SP352097WO00 36/104
used in the pico cell 11. For example, the plurality of CCs include one or more
NCTs.
[0145]
For example, the radio communication unit 220 can perform the radio 5 communication with one UE 300 simultaneously using the plurality of CCs. That is, the macro eNodeB 200 supports carrier aggregation. [0146] (Network communication unit 230)
The network communication unit 230 communicates with other 10 communication nodes. For example, the network communication unit 230 communicates with the pico eNodeB 100, other macro eNodeB 200 and MME, and the like. [0147]
(Storage unit 240)
15 The storage unit 240 stores a program and data for an operation of the
macro eNodeB 200. [0148]
For example, the storage unit 240 stores the synchronization relationship information indicating which CCs are mutually synchronized among the plurality of 20 CCs used for the radio communication. [0149] (Control unit 250)
The control unit 250 supplies various functions of the macro eNodeB 200.
[0150]
25 The control unit 250 includes a synchronization relationship information
acquisition unit 251 and a communication control unit 253. [0151] (Synchronization relationship information acquisition unit 251)
The synchronization relationship information acquisition unit 251 acquires
30 synchronization relationship information indicating which CCs are mutually
synchronized among the plurality of CCs (that is, a synchronization relationship

SP352097WO00 37/104
between the CCs). [0152]
For example, the synchronization relationship information acquisition unit 251 acquires synchronization relationship information (that is, macro SR 5 information) indicating which CC is synchronized with which CC among one or more CCs used for the macro cell 21. [0153] - - SR2 and SR3
For example, the macro SR information indicates which CC of one or more
10 different CCs used for the macro cell 21 is synchronized with which CC of the plurality of CCs used for the pico cell 11. That is, the macro SR information includes synchronization relationship information (hereinafter referred to as "SR2 information") indicating the SR2 and synchronization relationship information (hereinafter referred to as "SR3 information") indicating the SR3 among the
15 synchronization relationships illustrated in FIG. 12. [0154]
More specifically, for example, the synchronization relationship information acquisition unit 251 acquires the synchronization relationship information (that is, the SR2 information and the SR3 information) indicating which CC of the CC i and
20 the CC 2 of the macro cell 21 is synchronized with which CC of the CC 3 and the CC 4 of one or more pico ceils 11. For example, when the CC I of the macro cell 21 is synchronized with the CC 3 of the pico cell 11 A, the SR2 information indicates that the CC 1 ofthe macro cell 21 is synchronized with the CC 3 of the pico cell 1 lA. [0155]
25 --SR1
For example, the one or more CCs used for the macro cell 21 include two or more CCs, and the macro SR information indicates which CCs are mutually synchronized among the one or more different CCs. That is, the macro SR information includes the synchronization relationship information (hereinafter
30 referred to as "SRI information") indicating SRI among the synchronization relationships illustrated in FIG. 12.

SP352097WO00 38/104
[0156]
More specifically, for example, the synchronization relationship information
acquisition unit 251 acquires the synchronization relationship information (that is,
the SRI information) indicating which CCs are mutually synchronized between the 5 CO 1 and the CC 2 of the macro cell 21. For example, when the CC I and the CO 2
of the macro cell 21 are mutually synchronized, the SRI information indicates that
the CC 1 and the CC 2 of the macro cell 21 are mutually synchronized.
[0157]
For example, as described above, the synchronization relationship 10 information acquisition unit 251 acquires the SRI information, the SR 2 information,
and the SR3 information as the synchronization relationship information, 'fhe SRI
information, the SR 2 information, and the SR3 information are stored in the storage
unit 240, and the synchronization relationship information acquisition unit 251
acquires the SRI information, the SR 2 information, and the SR3 information from 15 the storage unit 240.
[0158]
(Communication control unit 253)
The communication control unit 253 controls the radio communication in
the macro cell 21. For example, the communication control unit 253 supplies 20 control information to the UE 300 located in the macro cell 21.
[0159]
- Supply of synchronization relationship information
hi particular, in the embodiment, the communication control unit 253
supplies the synchronization relationship information indicating the synchronization 25 relationship between the plurality of CCs in the macro cell 21. In other words, the
communication control unit 253 supplies the synchronization relationship
information to the UE 300 located in the macro cell 2 i.
[0160]
--SR1,SR2, andSR3
30 For example, the communication control unit 253 supplies, in the macro cell
21, synchronization relationship hiformation (that is, the macro SR information)

SP352097WO00 39/104
indicating which CC is synchronized with which CC among one or more CCs used
for the macro cell 21.
[0161]
For example, the macro cell SR information is not supplied in the pico cell 5 11 bythepicoeNodeB 100. [0162] --SR2andSR3
As described above, for example, the macro SR information indicates which CC of one or more different CCs used for the macro cell 21 is synchronized with
10 which CC of the plurality of CCs used for the pico cell II. That is, the macro SR information includes the SR2 information and the SR3 infonnation. Therefore, the communication control unit 253 supplies the SR2 information and the SR3 information in the macro cell 21. [0163]
15 The supply of the SR2 information and the SR3 information can result in a
leduction in a load of the UE 300 in tiie carrier aggregation when the macro cell 21 and the pico cell 11 are deployed. For example, the UE 300 can also perform the radio communication simultaneously using the CC of the pico cell 11 and the CC of the macro cell 21. In this case, when the SR2 infonnation and the SR3 information
20 are not supplied to the UE 300, the UE 300 can separately verify all of the synchronization relationships between the CCs used for the pico cells 11 and the CC used for the macro cell 21. Conversely, when the SR2 information and the SR3 information are supplied to the UE 300, the UE 300 may verify only the restricted synchronization relationships. For this reason, the supply of the SR2 information
25 and the SR3 information can result in the reduction in the load of the UE 300. [0164]
The SR2 information and the SR3 information are supplied by the macro eNodeB 200. Thus, the UE 300 can reliably comprehend which CC is preferable to use among the CCs of the pico cell 11 in view of the use of the synchronization resuh
30 when the UE 300 enters the pico cell II, before the UE 300 enters the pico cell II. As a result, when the UE 300 enters the pico eel! 11, the UE 300 can more rapidly

SP352097WO00 40/104
use the CC (for example, the CC synchronized with the CC of the macro cell 21 during the use, the CC synchronized with the different CC of the pico eel! 11, or the like) that is preferable in view of the use of the synchronization result among the CCs of the pico cell H. 5 [0165]
Specifically, for example, the pico eNodeB 100 is assumed to supply the SR2 information using the system information. In this case, to use the CC that is preferable in view of the use of the synchronization result, the UE 300 receives the system information from tiie pico eNodeB 100. Then, after the UE 300 receives the
10 system information and then acquires and confirms the SR2 information, the UE 300 eventually uses the CC that is preferable in view of the use of the synchronization result. Therefore, when the UE 300 enters the pico cell 11, there is a probability' of the UE 300 not being connected to the pico eNodeB 100 when it attempts to use the CC that is preferable in view of the use of the synchronization result among the CCs
15 of the pieo eel! 1 i from the beginning. In paiticular, when the UE 300 is moving at a high speed, a situation in which the UE 300 is not connected to the pico eNodeB 100 despite having entered the pico cell 11 can also occur. On the other hand, as described above, when the macro eNodeB 200 supplies the SR2 information and the SR3 information, the UE 300 can acquire the SR2 information In advance from the
20 macro eNodeB 200 out of the pico cell 11. Therefore, the UE 300 can be connected to the pico eNodeB 100 using the CC that is preferable in view of the use of the synchronization result without receiving the system information from the pico eNodeB 100 again. That is, the UE 300 can use the CC that is preferable in view of the use of the synchronization result more rapidly.
25 [0166]
For example, the pico eNodeB 100 is assumed to supply the SR2 information using the RRC signaling. In this ease, the UE 300 uses one CC to establish connection to tiie pico eNodeB 100 without comprehending which CC is the CC that is preferable in view of the use of the synchronization result. Therefore,
30 to use the CC that is preferable in view of the use of the synchronization result, the UE 300 acquires the R2 information from the RRC signaling after the connection,

SP352097WO00 4i/i04
and then can use the CC that is preferable in view of the use of the synchronization
result again. On the other hand, as described above, when the macro eNodeB 200
supplies the SR2 information, the UE 300 can establish the connection to the pico
eNodeB 100 using the CC that is preferable in view of the use of the synchronization 5 result from the beginning. That is, the UE 300 can use the CC that is preferable in
view of the use of the synchronization result more rapidly.
[0167]
--SR1
As described above, for example, the macro SR information indicates which 10 CCs are mutually synchronized among one or more different CCs used for the macro
cell 21. That is, the macro SR information inchides the SRI information.
Therefore, the communication control unit 253 supplies the SRi information in the
macro cell 21.
[0168]
15 The supply of the SRI information results in a reduction in a load of the UE
300 in the carrier aggregation when the macro cell 21 and the pico cells 11 are
deployed. That is, when the SRI information is not supplied to the UE 300, the UE
300 can separately verify all of the synchronization relationships between the CCs
used for the macro cell 21. Conversely, when the SRI information is supplied to 20 the UE 300, the UE 300 may verify only the restricted synchronization relationships.
For this reason, the supply of the SRI information can result in the reduction in the
load oftheUE 300.
[0169]
1 he SRI information is supplied by the macro cNodcB 200. Thus, the UE 25 300 can acquire the SRi information without being located in one pico cell 11.
Accordingly, it is possible to reduce the load of the UE 300 independently of the
position of the UE 300.
[0170]
--SR4andSR5
30 The synchronization relationship information supplied in the macro cell 21
by the coninuinication control unit 253 does not include the synchronization

SP352097WO00 42/104
relationship infonnation (that is, that SR4 information) indicating which CCs are
mutually synchronized among the plurality of CCs used for the pico cell 11. That is,
the communication control unit 253 does not supply the SR4 information in the
macro ceil 21. 5 [0171]
For example, the synchronization relationship information supplied in the
macro cell 21 by the communication control unit 253 does not include the
synchronization relationship information (that is, the SR5 information) indicating
which CC of the pluralit}' of CCs used for the pico cell 11 is synchronized with 10 which CC of one or more CCs used for the different pico cell 11. That is, the
communication control unit 253 does not supply the SR5 information in the macro
cell2i.
[0172]
As described above, the various kinds of synchronization relationship 15 information are supplied in the macro cells 21 or not supplied. Hereinafter, the
kinds of synchronization relationship information supplied by the serving macro
eNodeB 200 and the kinds of synchronization relationship infonnation that are not
supplied will be confirmed with reference to FIG. 15.
[0173]
20 FIG. 15 is an explanatory diagram illustrating examples of kinds of
synchronization relationship infonnation supplied by the serving macro eNodeB 200.
As illustrated in FIG. 15, for example, the serving macro eNodeB 200 (the
communication control unit 253) supplies the SRI information, the SR2 information,
and the SR3 information in the macro cell 21. On the other hand, the serving macro 25 eNodeB 200 (the coinmunication control unit 253) does not supply the SR4
information and the SR5 information in the macro cell 2].
[0174]
- Supply method for synchronization relationship information
As a specific supply method, for example, the coinmunication control unit 30 253 supplies the synchronization relationship infonnation via the radio
communication unit 220 using the system information. More specifically, for


SP352097WO00 43/104
example, the communication control unit 253 generates the system information including the SRI information, the SR2 information, and the SR3 information and causes the radio communication unit 220 to transmit the system information in the macro cell 21. The communication control unit 253 may transmit the SRI 5 information, the SR 2 information, and the SR3 information to the UE 300 using the RRC signaling in the pico cell 11. [0175]
- Supply order of synchronization relationship information
For example, the communication control unit 253 supplies two or more 10 kinds of synchronization relationship information in an order according to importance of the kinds of synchronization relationship information. For example, the two or more kinds of synchronization relationship information include the SRI information, tlie SR2 information, and the SR3 information. The specific supply method has been described above in regard to the pico cNodeB 100. 15 [0176]
- Supply of supply spot information
For example, the communication control unit 253 supplies, in the macro cell 21, information (hereinafter referred to as "supply spot information") indicating a spot between the macro cell 21 and the pico cell 11 where each of the two or more
20 kinds of synchronization relationship information is supplied. The specific content of the supply spot information and the specific supply method have been described above in regard to the pico cNodeB 100. [0177] <4.3. Configuration of UE>
25 First, the configuration of the UE 300 according to the embodiment will be
described with reference to FIG. 16. FIG. 16 is a block diagram illustrating an example of the configuration of the UE 300 according to the embodiment. Referring to FIG. 16, the UE 300 includes an antenna unit 310, a radio communication unit 320, a storage unit 330, and a control unit 340.
30 [0178]
(Antenna unit 310)

SP352097WO00 44/104
The antenna unit 3!0 receives a radio signal and outputs the received radio
signal to the radio communication unit 320. The antenna unit 310 transmits a
transmission signal output by the radio communication unit 320.
[0179] 5 (Radio communication unit 320)
The radio communication unit 320 performs radio communication in the
pico ceil II and/or the macro cell 21. That is, the radio communication unit 320
perfomis the radio communication with the pico eNodeB 100 and/or the macro
eNodeB 200. For example, the radio communication unit 320 can simultaneously 10 use the plurality of CCs. Specifically, for example, the radio communication unit
320 can perform the radio communication with the pico eNodeB 100 and/or the
macro eNodeB 200 simultaneously using the plurality of CCs. That is, the UE 300
supports the carrier aggregation.
[0180] 15 (Storage unit 330)
The storage unit 330 stores a program and data for an operation of the UE
300.
[0181]
(Control unit 340)
20 The control unit 340 supplies various functions of the UE 300.
[0182]
The control unit 340 includes a synchronization relationship information
acquisition unit 341 and a communication control unit 343.
[0183] 25 (Synchronization relationship information acquisition unit 341)
- Acquisition of synchronization relationship information
The synchronization relationship information acquisition unit 341 acquires
the synchronization relationship information indicating whicli frequency bands are
mutually synchronized among the plurality of frequency bands. 30 [0184]
--SR4

SP352097WO00 45/104
In particular, in the embodiment, the synchronization relationship information acquisition unit 341 acquires synchronization relationship information (that is, the SR4 information) indicating which CCs are mutually synchronized among the pUuality of CCs used for the pico cell 11 from the information supplied in 5 the pico cell 11 by the pico eNodeB 100. The synchronization relationship information acquisition unit 341 does not acquire the SR4 information from the information supplied in the macro cell 21 by the macro eNodeB 200. [0185] --SR5
10 For example, the synchronization relationship information acquisition unit
341 acquires the SR5 information from the information supplied by the pico eNodeB 100 and does not acquire the SR5 information from the information supplied by the macro eNodeB 200. [0186]
15 --SR1,SR2, andSR3
For example, the synchronization relationship information acquisition unit 341 acquires the SRI information, the SR2 information, and the SR3 information from the information supplied by the macro eNodeB 200 and does not acquire the SRI information, the SR2 information, and the SR3 information from the
20 information supplied by the pico eNodeB 100. [0187] - Method of acquiring synchronization relationship information
As a specific supply method, for example, the synchronization relationship information acquisition unit 341 acquires various kinds of synchronization
25 relationship information from the system information transmitted by the macro eNodeB 200 or the pico eNodeB 100 via the communication unit 320. The synchronization relationship information acquisition unit 341 may acquire various kinds of synchronization relationship information from the RRC signaling via the radio communication unit 320.
30 [0188]
-Acquisition of supply spot information


SP352097WO00 46/104
For example, the synchronization relationship information acquisition unit 341 acquires information (that is, supply spot information) indicating a spot between the macro cell 21 and the pico cell 11 where each of the two or more kinds of synchronization relationship information is supplied. 5 [0189]
As a specific acquisition method, for example, when the UE 300 is in RRCConnected in the pico cell 11 or the macro cell 21, the synchronization relationship information acquisition unit 341 acquires the supply spot information using the RRC signaling via the radio communication unit 320. The supply spot
10 information may be acquired from the system information. [0190]
For example, the synchronization relationship information acquisition unit 341 comprehends the kinds of synchronization relationship information supplied by the macro eNodeB 200 from the supply spot information. Further, the
15 synchronization relationship information acquisition unit 341 also comprehends the kinds of synchronization relationship information supplied by the pico eNodeB 100 from the supply spot information. Then, the synchronization reiationship information acquisition unit 341 decides the kinds of synchronized relationship information to be acquired and acquires the kinds of decided synchronization
20 relationship information as described above. [0191] (Communication control unit 343)
The communication control unit 343 controls the radio communication by the UE 300.
25 [0192]
For example, the communication control unit 343 performs a synchronization procedure based on the acquired synchronization relationship information. More specifically, for example, the communication control unit 343 establishes synchronization with the CC that is preferable in view of the use of the
30 synchronization result based on the acquired synchronization relationship information and verifies the synchronization relation between the CCs. When the

47/104

SP352097WO00

number of mutually synchronized CCs is two or more, the communication control
unit 343 uses the synchronization result of the UE 300 in one CC of the two or more
CCs for another CC of the two or more CCs.
[0193] 5 «5. Flow of process»
Next, an example of the communication control process according to the
embodiment will be described with reference to FIGS. 17 to 20.
[0194]
(Supply of supply spot information)
10 FIG. 17 is an explanatory diagram illustrating an example of a first
communication control process on the side of a pico eNodeB 100 according to the
embodiment. The first communication control process is a process performed to
supply the supply spot information.
[0195]
15 In step S4I0, the communication control unit 153 of the pico eNodeB 100
determines whether there is the UE 300 entering RRCConnected in the pico cell 11.
When there is the UE 300, the process proceeds to step S420. Othenvise, the
process of step S4I0 is repeated.
[0196]
20 In step S420, the communication control unit 153 of the pico eNodeB 100
supplies the supply spot information using the RRC signaling to the UE 300 entering
RRCConnected in the pico cell 11 via the radio communication unit 120. Then,
the process returns to step S410.
[0197]
25 The first communication control process can be performed similarly in the
macro eNodeB 200.
[0198]
(Supply of synchronization relationship information by pico eNodeB)
FIG. 18 is an explanatory diagram illustrating an example of a second 30 communication control process on the side of the pico eNodeB 100 according to the
embodiment. The second communication control process is a process performed to

SP352097WO00 48/104
supply the synchronization relationship information. [0199]
In step S510, the synchronization relationship information acquisition unit 151 acquires the synchronization relationship information supplied by the pico 5 eNodeB 100. [0200]
In step S520, the communication control unit 153 supplies the synchronization relationship information using the system information via the radio communication unit 120. Then, the process returns to step S510. 10 [0201]
(Supply of synchronization relationship information by macro eNodeB)
FIG. 19 is an explanatory diagram illustrating an example of a communication control process on the side of the macro eNodeB 200 according to the embodiment. The communication control process is a process performed to 15 supply the synchronization relationship information. [0202]
In step S610, the synchronization relationship information acquisition unit 251 acquires the synchronization relationship information supplied by the macro eNodeB 200. 20 [0203]
In step S620, the communication control unit 253 supplies the synchronization relationship information using the system information via the radio communication unit 220. Then, the process returns to step S610. [0204] 25 (Communication control process by UE)
FIG. 20 is an explanatory diagram illustrating an example of a communication control process on the side of the UE 300 according to the embodiment. The communication control process starts, for example, when the UE 300 enters RRC_Connected in the pico cell 11 or the macro cell 21. 30 [0205]
First, in step 5710, the synchronization relationship information acquisition

SP352097WO00 49/104
unit 341 acquires the supply spot information from the RRC signaling via the radio
communication unit 320.
[0206]
Then, in step S720, the synchronization relationship information acquisition 5 unit 341 comprehends the kind of synchronization relationship information supplied
by the macro eNodeB 200 from the supply spot information.
[0207]
In step S730, the synchronization relationship information acquisition unit
341 comprehends the kind of synchronization relationship information supplied by 10 the pico eNodeB 100 from the supply spot information.
[0208]
Then, in step S740, the synchronization relationship information acquisition
unit 341 decides the kinds of synchronization relationship information to be acquired.
[0209]
15 Thereafter, in step S750, the synchronization relationship information
acquisition unit 341 acquires the kinds of decided synchronization relationship
information via the communication unit 320 from the system information transmitted
by the macro eNodeB 200 or the pico eNodeB 100.
[0210]
20 Then, in step S760, the communication control unit 343 performs the
synchronization procedure based on the acquired synchronization relationship
information. Then, the process ends.
[0211]
«6. First modification example»
25 Next, a first modification example of the embodiment will be described with
reference to FIGS. 21 and 22.
[0212]
In the example of the above-described embodiment, the macro cNodeB 200
supplies the synchronization relationship information (that is, the SR2 information 30 and the SR3 information) indicating which CC of one or more CCs used for the
macro cell 21 is synchronized with which CC of the pluraiity of CCs used for the

SP352097WO00 50/104
pico cell 11.
[0213]
However, when the synchronization relationship information is supplied by
the macro eNodeB 200, valuable radio resources in the macro cell 21 may be 5 consumed.
[0214]
Accordingly, the first modification example of the embodiment is
configured to further suppress consumption of radio resources of the macro cell.
Specifically, in the fnst modification example, the SR2 information and tiie SR3 10 information are transmitted by the pico eNodeB 100 instead of being transmitted by
the macro eNodeB 200.
[0215]
(Pico eNodeB 100 - synchronization relationship information acquisition unit 151)
-Acquisition of synchronization relationship information
15 A synchronization relationship information acquisition unit 151 of the pico
eNodeB lOOA acquires synchronization relationship information (that is, the SR2
information) indicating which CC of one or more CCs used for the macro cell 21 is
synchronized with which CC of the plurality of CCs used for the pico cell 11 A.
[0216]
20 hi addition, for example, the synchronization relationship information
acquisition unit 151 of the pico eNodeB lOOA acquires the synchronization
relationship information (that is, the SR3 information) indicating which CC among at
least one CC used in the macro cell re is synchronized with which CC among the
plurality of CCs used in another pico cell IIB. 25 [0217]
(Pico eNodeB 100 - communication control unit 153)
- Supply of synchronization relationship information
--SR2
The communication control unit 153 supplies the SR2 information in the 30 pico cell 11. The SR2 information is not supplied in the macro cell 21 by the macro
eNodeB 200. That is, of the macro SR information, the SR2 information is supplied

51/104

SP352097WO00

by the pico eNodeB 100 rather than the macro eNodeB 200. [0218J
Accordingly, the radio resources of the macro cell 21 are not used to supply the SR2 information. That is, the supply of the SR2 information by the pico 5 cNodeB 100 can result in the suppression of the consumption of the radio resources of the macro cell 21. [02I9J --SR3
The communication control unit 153 supplies the SR3 information in the 10 pico cell II. The SR3 information is not supplied in the macro cell 21 by the macro eNodeB 200. That is, of the macro SR information, the SR3 information is supplied by the pico eNodeB 100 rather than the macro eNodeB 200. [0220]
Accordingly, the radio resources of the macro cell 21 arc not used to supply 15 the SR3 information. That is, the supply of the SR3 information by the pico eNodcB 100 can result in the suppression of the consumption of the radio resources of the macro cell 21. [0221J
By supplying the SR3 information by the pico eNodeB 100, at the time of 20 movement fiom the serving pico cell llA to the pico cell HB, the UE 300 can acquire the SR3 information in advance in the pico cell I lA before the UE 300 enters the pico cell I IB. Accordingly, the UE 300 can use the CC that is preferable in view of the use of the synchronization result among the CCs used for the pico cell I IB more rapidly. 25 [0222] --SRI
For example, the macro eNodeB 200 supplies the synchronization relationship information (that is, the SRI information) indicating which CCs arc mutually synchronized among the plurality of CCs used for the macro cell 21, as in 30 the above-described embodiment. [0223]

SP352097WO00 52/104
As described above, various kinds of synchronization relationship information are supplied or not supplied in the pico cell II. Hereinafter, kinds of synchronization relationship information supplied by the serving pico cNodeB lOOA and kinds of synchronization relationship information not supplied in the first 5 modification example will be confirmed with reference to FIG. 21. [0224]
FIG. 21 is an explanatory diagram illustrating examples of kinds of synchronization relationship information supplied by a serving pico eNodeB lOOA according to a first modification example of the embodiment. As illustrated in FIG. 10 21, for example, the serving pico eNodeB lOOA (the communication control unit 153) supplies the SR2 information, the SR3 information, the SR4 information, and the SR5 information in the pico cell UA. Conversely, the serving pico eNodeB lOOA (the communication control unit 153) does not supply the SRI information in the pico cell 11 A. 15 [0225]
(Macro eNodeB 200 - synchronization relationship information acquisition unit 251)
The synchronization relationship information acquisition unit 251 of the macro eNodeB 200 does not acquire the SR2 information among the macro SR infonnation. For example, the synchronization relationship information acquisition 20 unit 251 does not acquire the SR3 information among the macro SR infonnation either. Conversely, for example, the synchronization relationship information acquisition unit 251 acquires the SRI information among the macro SR information. [0226]
(Macro eNodeB 200 - communication control unit 253) 25 - Supply of synchronization relationship information
The communication control unit 253 does not supply the SR2 information among the macro SR information in the macro cell 21. For example, the communication control unit 253 does not supply the SR3 information among the macro SR information in the macro cell 21. Conversely, for example, the 30 communication control unit 253 supplies the SRI information among the macro SR information in the macro cell 21.

SP352097WO00 53/104
[0227]
As described above, various kinds of synchronization relationship
information are supplied or not supplied in the macro cell 21. Hereinafler, kinds of
synchronization relationship information supplied by the serving macro eNodeB 200 5 and kinds of synchronization relationship information not supplied in the first
modification example will be confirmed with reference to FIG. 22.
[0228]
FIG. 22 is an explanatoiy diagram illustrating examples of the kinds of
synchronization relationship information supplied by the serving macro eNodcB 200 10 according to the first modification example of the embodiment. As illustrated in
FIG. 22, for example, the serving macro eNodeB 200 (the communication control
unit 253) supplies the SRI information in the macro cell 21. Conversely, the
serving macro eNodeB 200 (the communication control unit 253) does not supply the
SR2 information, the SR3 information, the SR4 information, and the SR5 15 information in the macro cell 21.
[0229]
The first modification example of the embodiment has been described above.
According to the first modification example, the SR2 information and the SR3
information are not transmitted by the macro eNodeB 200. Accordingly, it is 20 possible to further suppress the consumption of the radio resources of the macro ceil.
[0230]
«7. Second modification example»
Next, a second modification example of the embodiment will be described
with reference to FIGS. 23 to 25. 25 [0231]
In the above-described embodiment, the synchronization relationship
information related to the CC used in the serving macro cell 21 and the pico cell 11
overlapping with the macro cell 21 is supplied.
[0232]
30 However, in this case, to use the CC that is preferable in view of the use of
the synchronization result even after handover to the adjacent macro cell 21, the UE

SP352097WO00 54/104
300 acquires the synchronization relationship information in the adjacent macro cell 2i again after the handover. As a result, a considerable amount of time may be necessary until the CC that is preferable in view of the use of the synchronization result is used. 5 [0233]
Accordingly, in the second modification example of the embodiment, the CC that is preferable in view of the use of the synchronization result can be used more rapidly even after the handover to the adjacent macro cell 21. Specifically, in the second modification example, the synchronization relationship information
10 related to a different macro cell 21 adjacent to the serving macro cell 21 is ftnther supplied. [0234] (Synchronization relationship information suppliable to UE)
First, in the second modification example of the embodiment, the kinds of
15 synchronization relationship information which can be supplied by the serving pico eNodeB lOOA or the serving inacro eNodeB 200 in a certain UE 300 will be described with reference to FIG. 23. [0235]
FIG. 23 is an explanatory diagram illustrating examples of kinds of
20 suppliable synchronization relationship information according to a second modification example of the embodiment. Referring to FIG. 23, pico eNodeBs 100, pico cells li, macro eNodeBs 200, and macro cells 21 are illustrated. The macro ceil 21A and the macro ceil 21B are adjacent to each other. In this example, the UE 300 is located in the cell llA, the pico cell I lA is a serving pico cell in the UE 300,
25 and the macro cell 21A is a serving macro cell in the UE 300. In FIG. 23, two CCs (CC 1 and CC 2) used for the macro cells 21 and two CCs (CC 3 and CC 4) used for the pico cells 11 are illustrated. [0236]
According to the second modification example, in the deployment of these
30 cells, for example, information indicating the following kinds of synchronization relationships (SR) can be supplied by the pico eNodeB lOOA or the macro eNodeB

SP352097WO00 55/104
200A:
SRI; a synchronization relationship between the CCs of the serving macro cell 21 A;
SR2: a synchronization relationship between the CCs of the serving macro 5 cell 21Aand the CCs of the serving pico cell 11 A;
SR3: a synchronization relationship between the CCs of the serving macro cell 2IA and the CCs of the other pico cell UB overlapping with the serving macro celi21A;
SR4: a synchronization relationship between the CCs of the serving pico 10 cell 11 A;
SR5: a synchronization relationship between the CCs llA of the serving pico cei! and the CCs of the other pico cell UB overlapping with the serving macro cell 21 A;
SR6: a synchronization relationship between the CC of the serving pico cell 15 llAand the CC ofthe adjacent macro cell 21B;
SR7: a synchronization relationship between the CC ofthe other pico cell 1 IB overlapping with the serving macro cell 21A and the CC ofthe adjacent macro cell21B;
SR8: a synchronization relationship between the CCs ofthe adjacent macro 20 cell 21B; and
SR9: a synchronization relationship between the CC ofthe adjacent macro
cell 21B and the CC ofthe pico cell IIC overlapping with the adjacent macro cell
21B.
[0237]
25 The above-described SRI lo SR5 have been described with reference to FIG.
12. hi pailicular, in the second modification example, for example, SR6 to SR9 are further supplied by the serving pico eNodeB 1OOA or the serving macro eNodeB 200. [0238]
(Pico eNodeB 100-Synchronization relationship information acquisition unit 151) 30 - - SR6
As described above, the synchronization relationship information

SP352097WO00 56/104
acquisition unit 151 of the pico eNodeB lOOA acquires the synchronization relationship information indicating which CC of the plurality of CCs used for the macro cell 21A is synchronized with which CC of one or more CCs used for different cells other than the macro cell 21 and the pico cell 11 A. 5 [0239]
hi particular, in the second modification example, for example, the different cells include the macro cell 21B adjacent to the macro cell 21A. That is, the synchronization relationship information acquisition unit 151 acquires synchronization relationship information (hereinafter referred to as "SR6
10 information") indicating SR6 among the synchronization relationships illustrated in FIG. 23. [0240] -SR7
The synchronization relationship information acquisition unit 151 of the
15 pico eNodeB lOOA acquires synchronization relationship information indicating which CCs are mutually synchronized among a plurality of CCs used for a different cell other than the macro cell 21A and the pico cell 11 A. [0241]
For example, the different cells are the different pico cell 1 IB partially or
20 entirely overlapping with the macro cell 21A and the macro cell 2IB adjacent to the macro cell 21 A. The synchronization relationship information indicates which CC of one or more CCs used for the pico cell I IB is synchronized with which CC of one or more CCs used for the macro ceil 21B. That is, the synchronization relationship information acquisition unit 151 acquires synchronization relationship information
25 (hereinafter referred to as "SR7 information") indicating SR7 among the synchronization relationships illustrated in FIG. 23. [0242]
(Pico eNodeB lOO-Comnuinication control unit 153) - Supply of synchronization relationship information
30 - - SR6
As described above, the communication control unit 153 of the pico


SP352097WO00 57/104
eNodeB lOOA supplies in the pico cell 11 the synchronization relationship information indicating which CC of the plurality of CCs used for the macro cell 21A is synchronized with which CC of one or more CCs used for different cells other than the macro cell 21 and the pico cell 11 A. 5 [0243]
In particular, in the second modification example, as described above, for example, the different cells include the macro cell 21B adjacent to the macro cell 2IA. That is, the communication control unit 153 of the pico eNodeB lOOA supplies, in the pico cell 11 A, the synchronization relationship information (that is,
10 the SR6 information) indicating which CC of the plurality of CCs used for the pico cell llA is synchronized with which CC of one or more CCs used for the macro cell 2IB. [0244]
The SR6 information is not supplied in the macro cell 21A by the macro
15 eNodeB 200A. [0245]
The supply of the SR6 information can result in a reduction in a load of the UE 300 in the carrier aggregation when the macro cell 21 and the pico cell II are deployed. For example, the pico cell HA can be overlapping with both of the
20 macro cell 21A and the macro cell 2IB. In this case, when the UE 300 performs handover from the macro cell 21A to the macro cell 21B, the UE 300 can communicate with the pico eNodeB lOOA using the CC of the pico cell 1 lA even after the handover. In this case, when the SR6 information is not supplied to the UE 300, the UE 300 can separately verify all of the synchronization relationships
25 between the CCs used in the pico cell 11A and the CCs used for the macro cell 2!B. Conversely, when the SR6 information is supplied to the UE 300, the UE 300 may verify only the restricted synchronization relationships. Therefore, the supply of the SR6 information can result in the reduction in the load of the UE 300.

CLAIMS
Claim I
A communication control device comprising;
a communication control unit configured to control radio communication in a small cell partially or entirely overlapping with a mj^cro cell; and
an acquisition unit configured to acquire fnst synchronization relationship information indicating which frequency bands are mutually synchronized among a phirality of frequency bands used for the small cell,
wherein the first synchronization relationship information is supplied in the small cell by the communication control unit and is not supplied in the macro cell by a base station of the macro cell.
Claim 2
The communication control device according to claim 1, wherein second synchronization relationship information indicating which frequency band is synchronized with which frequency band among one or more different frequency bands used for the macro cell is supplied in the macro cell by the base station of the macro cell.
Claim 3
The communication control device according to claiin 2, wherein the second synchronization relationship information indicates which frequency band of the one 01' more different frequency bands used for the macro cell is synchronized with which frequency band of the plurality of frequency bands used for the small cell.
Claim 4
The communication control device according to claim 2,
wherein the one or more different frequency bands used for the macro cell
include two or more frequency bands, and
wherein the second synchronization relationship information indicates
which frequency bands are mutually synchronized among the one or more different

Claim 5
The communication control device according to claim I,
wherein the acquisition unit acquires second synchronization relationship
information indicating which frequency band of one or more different frequency
bands used for the macro cell is synchronized with which frequency band of the
plurality of frequency bands used for the small cell, and
wherein the second synchronization relationship information is supplied in
the small cell by the communication control unit and is not supplied in the macro cell
by the base station of the macro cell.
Claim 6
The communication control device according to claim 1, wherein the acquisition unit acquires third synchronization relationship information indicating which frequency band of the plurality of frequency bands is synchronized with which frequency band among one or more fi-equeney bands used for a different ceil other than the macro cell and the small cell, and
wherein the third synchronization relationship information is supplied in the small ceil by the communication control unit and is not supplied in the macro cell by the base station of the macro eell.
Claim 7
The communication control device according to claim 6, wherein the different cell includes a different small cell paitially or entirely overlapping with the macro cell.
Claim 8
The communication control device according to claim 6, wherein the different cell includes a different macro cell adjacent to the macro cell.

Claim 9
The communication control device according to claim I,
wherein the acquisition unit acquires fourth synchronization relationship
information indicating which frequency bands are mutually synchronized among a
plurality of frequency bands used for a different cell other than the macro ceil and the
small cell, and
wherein the fourth synchronization relationship information is supplied in
the small cell by the communication control unit and is not supplied in the macro cell
by the base station of the macro cell.
Claim 10
The communication control device according to claim 9,
wherein the different cell is a different macro cell adjacent to the macro cell
and a different small cell partially or entirely overlapping with the macro cell, and
wherein the fourth synchronization relationship information indicates which
frequency band of one or more frequency bands used for the different small cell is
synchronized with which frequency band of one or more frequency bands used for
the different macro ceil.
Claim 11
The communication control device according to claim I, wherein the communication control unit supplies, in the small cell, information indicating that each of two or more kinds of synchronization relationship information including the first synchronization relationship information is supplied to one of the macro cell and the smali cell.
Claim 12
The communication control device according to claim I, wherein each of two or more kinds of synchronization relationship information including the first synchronization relationship information is supplied using one of signaling to a separate terminal device and system information common to terminal devices

according to a kind of synchronization relationship information.
Claim 13
The communication control device according to claim I, wherein each of two or more kinds of synchronization relationship information including the first synchronization relationship information is supplied in the small cell by the communication control unit using signaling to a separate terminal device or is supplied in the macro cell by the base station of the macro cell using system information common to terminal devices.
Claim 14
The communication control device according to claim 12, wherein the communication control unit supplies, in the small cell, information indicating that each of the two or more kinds of synchronization relationship information including the first synchronization relationship information is supplied using one of the signaling to the separate terminal device and the system information common to the terminal devices.
Ciaim15
The communication control device according to claim 1, wherein the communication control unit supplies each of two or more kinds of synchronization relationship information including the first synchronization relationship information in order according to importance of the kinds of synchronization relationship information.
Claim 16
A communication control method comprising:
controlling radio communication in a small cell partially or entirely overlapping with a macro cell; and
acquiring first synchronization relationship information indicating which frequency bands are mutually synchronized among a plurality of frequency bands

used for the small cell,
wherein the first synchronization relationship information is supplied in the small cell by a base station of the small cell and is not supplied in the macro cell by the base station of the macro cell.
Claim 17
A communication control device comprising;
a communication control unit configured to control radio communication in a macro cell partially or entirely overlapping with a small cell; and
an acquisition unit configured to acquire synchronization relationship information indicating which frequency bands are mutually synchronized among a plurality of frequency bands,
wherein the communication control unit supplies the synchronization relationship information in the macro cell,
wherein the synchronization relationship information does not include first synchronization relationship information indicating which frequency bands are mutually synchronized among a plurality of frequency bands used for the small cell, and
wherein the first synchronization relationship information Is supplied by a base station of the small cell.
Claim 18
The communication control device according to claim 17,
wherein the acquisition unit acquires fifth synchronization relationship
information indicating which frequency bands are mutually synchronized among a
plurality of frequency bands used for a different cell other than the macro cell and the
small ceil, and
wherein the communication control unit supplies the fifth synchronization
relationship information in the macro cell.
Claim 19

The communication control device according to claim 18, ^^'hercin the different cell is a different macro cell adjacent to the macro cell
Claim 20
A terminal device comprising:
a radio communication unit configured to perform radio connnunication in a
macro cell or a small cell paitially or entirely overlapping with the macro cell, and
<
an acquisition unit configured to acquire first syncln"onization relatipnslup information indicating which fiequency bands are mutually synclnonized among a plurality of frequency bands used for the small cell from infonnation supplied in tlie small ceil b)' a base station of the small cell and configured not to acquire the first S3'nchronization relationship infoiniation fi'om information supplied in the macro cell by a base station of the macro cell.