JP2013197961A - Communication system, mobile station device, small base station device, and communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication system, mobile station device, small base station device, and communication method that avoid decrease in utilization efficiency of frequency resources.SOLUTION: A communication system comprises a macrocell base station device, a small base station device whose cell covers a part of the cell of the macrocell base station device, and a mobile station device. The mobile station device is provided with: a transmission/reception unit that communicates with the small base station device by using a first frequency band; and a communication control unit that generates request information requesting to use a second frequency band different from the first frequency band to communicate with the small base station device, and transmits the request information to the small base station device.

Description

  The present invention relates to a communication system, a mobile station apparatus, a small base station apparatus, and a communication method.

  In wireless communication, data is transmitted and received using radio waves between a base station device and a mobile station device. In LTE-A (Long Term Evolution-Advanced), which is one of the standards for wireless communication, it is allowed to use various mobile station apparatuses for communication. The types of ranges covered by the base station device include, for example, a macro cell (also called a macro cell) and a micro cell (also called a micro cell, pico cell, femto cell, and H). A macro cell is a cell with a large range in which radio waves reach a mobile station device (for example, a radius of several hundreds to several tens of kilometers). A microcell is a cell that has a smaller range in which radio waves reach a mobile station device (for example, a radius of several meters to several hundred meters).

  As a communication system in which macro cells and micro cells are mixed, there is an access method arrangement method described in Patent Document 1, for example. In Patent Literature 1, when an MME (Mobility Management Entity) receives an overload notification message from the eNB (base station apparatus) that instructs an eNB cell to be overloaded, an MNB (Mobility Management Entity) selects an HeNB corresponding to the eNB cell. It is described that an identification is made (a plurality of identified HeNBs may exist), and an instruction is sent to this HeNB to change the HeNB access method from a closed method to a release method or a hybrid method. ing.

JP 2011-4399 A

  However, according to the communication system described in Patent Document 1, when an overload occurs in a certain base station device, the access methods of all base station devices in which the cell coverage of the base station device overlaps are switched. That is, since the mobile station device cannot access another base station device by specifying it, the frequency resource utilization efficiency may be reduced.

  The present invention has been made in view of the above points, and provides a communication system, a mobile station apparatus, a base station apparatus, and a communication method that do not reduce the use efficiency of frequency resources.

(1) The present invention has been made to solve the above-described problems, and one aspect of the present invention is a small-sized macro cell base station apparatus and a small area of a cell of the macro cell base station apparatus. A communication system comprising a base station device and a mobile station device, wherein the mobile station device communicates with the small base station device using a first frequency band, and the first frequency band Includes a communication control unit that generates request information indicating that communication with the small base station apparatus is requested using a different second frequency band, and transmits the request information to the small base station apparatus. It is the communication system characterized by this.

(2) According to another aspect of the present invention, in the communication system described above, the mobile station device includes a communication measurement unit that measures a communication amount with the small base station device, and the communication control unit includes the communication Whether or not to communicate using the second frequency band is determined based on the communication amount measured by the measurement unit.

(3) According to another aspect of the present invention, in the communication system described above, the communication control unit searches for a macro cell base station apparatus capable of communication using the second frequency band.

(4) According to another aspect of the present invention, in the communication system described above, the communication control unit transmits, as the request information, location information indicating that the communication control unit is located in a cell of the searched macro cell base station device. It is characterized by doing.

(5) According to another aspect of the present invention, in the communication system described above, the communication control unit adds the request information to measurement information related to communication with the small base station apparatus and transmits the measurement information to the small base station apparatus. It is characterized by doing.

(6) According to another aspect of the present invention, in the communication system described above, when the communication control unit detects a plurality of communicable macro cell base station apparatuses, the macro cell base station apparatus having the highest communication quality is selected. It is characterized by.

(7) Another aspect of the present invention is a communication system including a macro cell base station apparatus, a small base station apparatus that uses a partial area of a cell of the macro cell base station apparatus as a cell, and a mobile station apparatus. The small base station device communicates with the mobile station device using a first frequency band, and the macro cell base station device uses a second frequency band different from the first frequency band. A communication system comprising: a communication control unit that generates request information indicating that communication with the mobile station apparatus is requested, and transmits the request information to the mobile station apparatus.

(8) In another aspect of the present invention, the transmitter / receiver that communicates with the small base station device using the first frequency band, and the second frequency band that is different from the first frequency band are used. A communication control unit for generating request information indicating requesting communication with a macro base station device having a cell of the base station device as a part of its own cell, and transmitting the request information to the small base station device; A mobile station apparatus comprising:

(9) In another aspect of the present invention, a transmitting / receiving unit that communicates with a mobile station apparatus using a first frequency band, and a second frequency band different from the first frequency band are used. A communication control unit that generates request information representing a request for communication between the macro base station apparatus and a mobile station apparatus having a partial area of the cell as a cell, and transmits the request information to the mobile station apparatus; It is a small base station apparatus characterized by comprising.

(10) Another aspect of the present invention is a communication method in a mobile station apparatus, wherein the mobile station apparatus communicates with a small base station apparatus using a first frequency band, and the mobile station apparatus Request information representing requesting communication with a macro base station apparatus using a second frequency band different from the first frequency band as a part of the cell of the small base station apparatus. And transmitting the request information to the small base station apparatus.

(11) Another aspect of the present invention is a communication method in a small base station apparatus, wherein the small base station apparatus communicates with a mobile station apparatus using a first frequency band, and the small base station The apparatus requests communication between the macro base station apparatus using a second frequency band different from the first frequency band and having a partial area of its own cell as a cell, and the mobile station apparatus. Generating a request information to be expressed, and transmitting the request information to the mobile station apparatus.

  According to the embodiment of the present invention, the utilization efficiency of frequency resources does not decrease.

1 is a conceptual diagram illustrating a communication system according to a first embodiment of the present invention. It is a conceptual diagram showing an example of the frequency band used for transmission / reception of data. It is a conceptual diagram showing the other example of the frequency band used for transmission / reception of data. It is the schematic showing the structure of the communication system which concerns on this embodiment. It is the schematic showing the structure of UE which concerns on this embodiment. It is the schematic showing the structure of HeNB which concerns on this embodiment. It is the schematic showing the structure of eNB which concerns on this embodiment. It is a sequence diagram showing the communication processing which concerns on this embodiment. It is a flowchart showing the eNB search process which concerns on this embodiment. It is a sequence diagram showing the modification of the communication processing which concerns on this embodiment. It is a sequence diagram showing the other modification of the communication processing which concerns on this embodiment. It is a sequence diagram showing the other modification of the communication processing which concerns on this embodiment. It is the schematic showing the structure of the communication system which concerns on the 2nd Embodiment of this invention. It is the schematic showing the structure of HeNB which concerns on this embodiment. It is a sequence diagram showing the communication processing which concerns on this embodiment.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a conceptual diagram showing a communication system 1 according to the present embodiment.
The communication system 1 includes an eNB 12, a HeNB 13-1, 13-2, 13-3, and a UE. HeNB13-1, 13-2, and 13-3 may be named generically as HeNB13.

The eNB 12 is a macro cell base station apparatus (macro cell eNodeB) that transmits and receives data wirelessly to and from the UE 14. UE (User Equipment) is another name for a mobile station apparatus. In FIG. 1, a cell 32 is a macro cell that represents a range in which radio waves of the eNB 12 reach, that is, a range in which data can be transmitted and received with the UE 14. The radius of the cell 32 is, for example, a relatively wide range of several hundred m to several tens km. That is, the macro cell base station apparatus is a base station apparatus having a wide communication range with the mobile station apparatus (typically, a radius of several hundred m to several tens km).
The HeNBs 13-1, 13-2, and 13-3 are small base station devices (Home eNodeB [indoor base station device], micro cell eNodeB [micro cell base station device]) that transmit and receive data wirelessly with the UE 14. pico cell eNodeB [picocell base station apparatus] and femto cell eNodeB [femtocell base station apparatus]). In the present embodiment, the number of HeNBs is not limited to the three illustrated, and may be one, two, or more than three.
In FIG. 1, cells 33-1, 33-2, and 33-3 represent ranges where radio waves of HeNBs 13-1, 13-2, and 13-3 reach, respectively. The radii of the cells 33-1, 33-2, and 33-3 are, for example, a relatively narrow range of several meters to several tens of meters. The areas of the cells 33-1, 33-2, and 33-3 shown in FIG. The cells 33-1, 33-2, and 33-3 may be collectively referred to as the cell 33. That is, the small base station device is a base station device having a narrow range (typically a radius of several meters to several tens of meters) in which communication with the mobile station device is possible.

  The cell 33 provided by the HeNB 13 may be any of the following types (1) to (3). (1) Open cell: Similar to a macro cell, it is a cell to which all UEs can be connected. As open cell identification information, for example, PCI (Physical Cell Identity) in the same format as that of a macro cell is used. (2) CSG cell (Closed Subscriber Group cell): A cell to which only UEs (CSG members) of subscribers limited in advance can connect. Such a group of subscribers is called a CSG. As the identification information of the CSG cell, for example, PCI dedicated to CSG is used. A CSG-ID is transmitted as part of the system information to UEs located in the CSG cell. The system information is control information common to UEs in the area. The CSG-ID is CSG identification information. (3) Hybrid cell: A cell that can be connected to a CSG member as a CSG cell and to a non-CSG member as an open cell. Therefore, PCI having the same format as that of an open cell is used as hybrid cell identification information. Moreover, CSG-ID is transmitted as a part of system information to UE located in the hybrid cell. The HeNB 13 may allocate frequency resources with priority over CSG members over non-CSG members.

UE14 is a mobile station apparatus (User Equipment) which transmits / receives data by radio | wireless between at least any one of eNB12, HeNB13-1, 13-2, and 13-3. The UE 14 is, for example, a mobile phone or a personal digital assistant (PDA).
In addition, in the following description, when not distinguishing eNB12, HeNB13-1, 13-2, and 13-3, or when these are named generically, it may only call a base station apparatus. Moreover, when not distinguishing HeNB13-1, 13-2, 13-3, or when these are named generically, it may only be called HeNB13.

  The communication system 1 according to the present embodiment includes an eNB 12, a HeNB 13 having a partial region of the cell 32 as a cell, and a UE 14. UE14 communicates with eNB12 using the electromagnetic wave of a certain frequency band A (henceforth the band A). UE14 produces | generates the request information showing requesting | requiring communication with eNB12 using the frequency band B different from the frequency band A. FIG. UE14 transmits the produced | generated request information to HeNB13. Thereby, the communication system 1 performs carrier aggregation (CA).

(Carrier aggregation)
Next, CA will be described. CA is a technology that aggregates (aggregates) two or more different frequency bands (component carriers; component carriers, CCs), and simultaneously transmits and receives data using these frequency bands. CC is a unit of a communication band in which data is allocated for each UE. Each CC includes a plurality of resource blocks (RBs). RB is a unit (for example, 180 kHz) of a frequency band to which data in an OFDM (Orthogonal Frequency Division Multiplexing) signal frame is assigned.

FIG. 2 is a conceptual diagram illustrating an example of a frequency band used for data transmission / reception.
In FIGS. 2A and 2B, the horizontal axis represents frequency.
FIG. 2A shows that the HeNB 13-1 transmits data to the UE 14 using the PCC of the band B before the CA process. FIG. 2B shows that, after CA processing, the HeNB 13-1 transmits data to the UE 14 using PCC (Primary Component Carrier) of the band B to the UE 14, and at the same time, the eNB 12 transmits the SCC of the band A to the UE 14. It represents transmitting data using (Secondary Component Carrier, secondary component carrier). At this time, UE14 receives the data from the same other party apparatus (for example, another mobile station apparatus) using the band A and the band B via HeNB13-1 and eNB12, respectively. Therefore, CA refers to virtually expanding the frequency band by simultaneously using a plurality of CCs for communication with the same counterpart device. CA may also refer to communication using an expanded frequency band. In the above example, the band used from the beginning before extending the band between the HeNB (small base station apparatus) 13-1 and the UE (mobile station apparatus) 14 is the band B (first frequency band). is there. When extending the band, the newly added band is the band A (second frequency band) between the eNB 12 (macro cell base station apparatus) and the UE 14 (mobile station apparatus). That is, CA means that the band B (first frequency band) and the band A (second frequency band) are aggregated to perform communication between the UE 14 and the counterpart device.

  The CCs to be aggregated may be frequency bands separated from each other as shown in FIG. 2, or may be frequency bands adjacent to each other. The band of each CC may be any band (for example, any one of 800 MHz, 2.4 GHz, and 3.4 GHz). The bandwidth of each CC may be any bandwidth (for example, any of 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, and 20 MHz). Further, the bandwidth and center frequency of each CC may be different between the uplink and the downlink.

  Here, the PCC is a frequency band serving as a reference for measurement control such as reception quality performed by the UE 14, detection of a downlink radio link failure, and transmission of an uplink control channel, for example. The PCC is a main band assigned to each UE. The SCC is a frequency band assigned to the UE other than the PCC. System information to be described later may include information representing PCC and information representing SCC used for communication with the UE 14 for each base station apparatus.

The number of CCs to be aggregated is not limited to two, and may be an integer greater than one (for example, three). The number of SCCs is not limited to one, and may be an integer greater than one.
FIG. 3 is a conceptual diagram illustrating another example of a frequency band used for data transmission / reception.
In FIG. 3, the horizontal axis represents frequency. In the example shown in FIG. 3, the number of CCs used is three. Of the three, one is a PCC in band B used in communication between the HeNB 13-1 and the UE. The other two are SCCs used in communication between the eNB 12 and the UE 14. The bands of the two SCCs are bands A and C.

(Physical signal / physical channel)
Next, physical signals and physical channels related to CA will be described.
In the communication system 1, physical signals and physical channels are used in data transmission (downlink) from the base station apparatus to the UE 14 and data transmission (uplink) from the UE 14 to the base station apparatus. The physical signal is a signal used for system synchronization, cell identification, and radio channel prediction. A physical channel is a channel for transmitting information generated at a higher layer (upper layer) than the physical layer. Signals and physical signals assigned to physical channels are assigned to predetermined times and frequencies as part of transmission signals or reception signals. This assignment is called mapping. Also, reconstructing the original signal from the assigned signal is called demapping.

  The downlink physical channel includes, for example, a physical downlink shared channel (PDSCH, Physical Downlink Shared Channel) and a physical downlink control channel (PDCCH, Physical Downlink Control Channel) shared by each UE. The PDSCH is a channel that transmits user data representing information transmitted and received by a user, for example. The PDCCH includes, for example, identification information (ID) of a UE that performs communication using PDSCH, information on transport (transmission) format of user data (that is, downlink scheduling information), a physical uplink shared channel (PUSCH, Physical Up Shared Channel). ) Is used to transmit control information such as the ID of a UE that performs communication using the user ID and information on the transport (transmission) format of user data (uplink scheduling grant). The PDCCH is also referred to as a downlink L1 / L2 control channel (Downlink L1 / L2 Control Channel). The downlink scheduling information and the uplink scheduling grant are also referred to as downlink control information (DCI, Downlink Control Information). Other physical downlink channels include physical broadcast channels (PBCH, Physical Broadcast Channel). PBCH is a channel that transmits information (for example, system information) unique to each base station apparatus to UEs located in the cell.

  The downlink physical signal includes a synchronization signal (SS, Synchronization Signal). The synchronization signal is a signal used for searching (cell search) or identifying a base station apparatus in which UE 14 is located. The synchronization signal includes a cell ID that is information for identifying the base station apparatus. The synchronization signal includes a primary synchronization signal (PSS, Primary Synchronization Signal) and a secondary synchronization signal (SSS, Secondary Synchronization Signal).

  The uplink physical channel includes a physical uplink shared channel (PUSCH, physical uplink shared channel) and a physical uplink control channel (PUCCH, physical uplink control channel) common to each UE. The PUSCH is a channel for transmitting user data, for example. The PUCCH is a channel for transmitting, for example, downlink quality information (CQI, Channel Quality Indicator) used for PUSCH scheduling, adaptive modulation / demodulation, and encoding processing (AMCS, Adaptive Modulation and Coding Scheme), and delivery confirmation information on PUSCH. is there. The downlink quality information may be channel state information (CSI, Channel State Indicator) including CQI, PMI (Precoding Matrix Indicator), and RI (Rank Indicator). The acknowledgment information includes an acknowledgment signal (ACK, Acknowledgment) indicating that the transmission signal has been properly received or a negative acknowledgment signal (NACK, Negative Acknowledgment) indicating that the transmission signal has not been properly received. May be included.

The uplink physical signal includes a demodulation reference signal (DMRS, Demodulation Reference Signal). The demodulation reference signal is a signal used by the base station apparatus for synchronization with the UE 14.
In the communication system 1, the above-described physical signals and physical channel signals may be collected and transmitted in one CC for each pair of one base station apparatus and one UE, or when CA is performed. May be distributed and transmitted to a plurality of CCs for each pair.

(System configuration)
Next, the configuration of the communication system 1 will be described.
FIG. 4 is a schematic diagram illustrating the configuration of the communication system 1 according to the present embodiment.
The communication system 1 includes an eNB 12, a HeNB 13, a UE 14, a MME (Mobility Management Entity) 15, and a RAN (Radio Access Network, radio access network) 11.

The RAN 11 is a network that connects at least one of the eNB 12 or the HeNB 13 and the UE 14 by radio (for example, RRC [Radio Resource Control] connection).
The eNB 12 and the HeNB 13 are each connected to the MME 15 by wire. The HeNB 13 may be connected to the MME 15 using, for example, a wired subscriber communication line such as an optical communication line or a fixed telephone line. Part or all of the HeNB 13 may be connected to the MME 15 via, for example, a HeNB-GW (indoor base station apparatus gateway device).

  The MME 15 includes base station identification information (for example, PCI), which is identification information for each base station apparatus, and registration area information (for example, TAI (Tracking Area Identity)) indicating a registration area including a plurality of base station apparatus cells. It is stored in association with each other in advance. Since all of the cells 33-1 to 33-3 are included in the cell 32, the HeNBs 13-1 to 13-3 all belong to the registration region identified by the same TAI as that of the eNB 12. When any of the HeNBs 13-1 to 13-3 is a CSG cell or a hybrid cell, the MME 15 stores a CSG-ID representing a CSG group including the HeNB related to the cell in association with the PCI of the cell. ing.

  The MME 15 receives a registration request signal from the UE 14 via a base station device (for example, the HeNB 13-1) corresponding to the stored PCI. The registration request signal is a signal indicating that the UE 14 registers as a device located in the cell of the base station device. Thereafter, the MME 15 generates communication path information (also called a bearer or a bearer) between the base station device and the counterpart device. MME15 transmits a registration confirmation signal to the base station apparatus (for example, HeNB13-1) which received the registration request signal.

  The MME 15 receives a communication path setting request signal from a base station apparatus (for example, eNB 12) corresponding to the stored PCI. The communication path setting request signal is a request for setting a communication path between the base station apparatus (or designated base station apparatus) and the counterpart apparatus in order to perform communication between the UE 14 and the counterpart apparatus. It is a signal showing. The MME 15 then generates communication path information between the base station apparatus and the counterpart apparatus related to the base communication path setting request signal. The MME 15 transmits a communication path setting confirmation signal to the base station apparatus (for example, eNB 12) that has received the communication path setting request signal.

  Thereby, the base station apparatus transmits and receives user data between the UE 14 and the counterpart apparatus via the communication path represented by the generated communication path information. However, when the base station apparatus that transmitted the registration request signal or the communication path setting request signal is a CSG cell, the MME 15 determines whether or not the UE 14 belongs to the CSG group corresponding to the CSG cell. The MME 15 generates the above-described communication path information when the UE 14 belongs to the CSG group, and does not generate the above-described communication path information when the UE 14 does not belong to the CSG group. Thereby, a CSG cell implement | achieves communication by UE which belongs to a CSG group, and a CSG cell refuses communication by UE which belongs to a CSG group. Further, the hybrid cell realizes communication by UEs belonging to the CSG group of the cell using parameters dedicated to the CSG group. The hybrid cell realizes communication by UEs not belonging to the CSG group of the cell using other parameters.

(UE configuration)
Next, the configuration of the UE 14 according to the present embodiment will be described.
FIG. 5 is a schematic diagram illustrating the configuration of the UE 14 according to the present embodiment.
The UE 14 includes a transmission / reception unit 141, a communication control unit 142, and a data processing unit 143.

  The transmission / reception unit 141 includes an antenna unit 1411, a wireless reception unit 1412, a demodulation unit 1413, a modulation unit 1414, and a wireless transmission unit 1415.

  The antenna unit 1411 outputs a radio frequency band reception signal (radio frequency reception signal) received from at least one of the eNB 12 and the HeNBs 13-1 to 13-3 to the radio reception unit 1412. The antenna unit 1411 transmits the radio frequency band transmission signal (radio frequency transmission signal) input from the radio transmission unit 1415 as a radio wave to the eNB 12 and the HeNBs 13-1 to 13-3.

  The radio reception unit 1412 down-converts the radio frequency reception signal input from the antenna unit 1411 to a base frequency band (baseband) and generates a modulation reception signal. When the radio reception unit 1412 generates a modulated reception signal, the radio reception unit 1412 performs down-conversion so that the center frequency becomes a base frequency (for example, 0 Hz) for each band represented by the CC information input from the communication control unit 142. This CC information represents a downlink CC that receives a signal from the base station apparatus. The radio reception unit 1412 outputs the modulated reception signal generated for each CC to the demodulation unit 1413.

  The demodulator 1413 demodulates the modulated received signal input from the radio receiver 1412 (for example, CP (Cyclic Prefix) removal, serial-parallel conversion, FFT (Fast Fourier Transform), demapping, parallel-serial conversion). Then, a reception signal is generated. The demodulator 1413 outputs the generated received signal to the communication controller 142 and the data processor 143. In demapping, the demodulator 1413 extracts allocation data determined for each signal included in a physical channel (for example, PDSCH, etc.) and for each type of physical signal (for example, user data signal, control signal, etc.). The received data is reconstructed by permuting the extracted data.

  The modulation unit 1414 modulates the transmission signal input from the communication control unit 142 and the data processing unit 143 (eg, serial-parallel conversion, mapping, IFFT (Inverse Fast Fourier Transform), parallel-serial conversion, CP insertion) ) To generate a modulated transmission signal. In the mapping, the modulation unit 1414 arranges data on the basis of an assignment determined for each signal included in a physical channel (for example, PUSCH and the like) and each type of physical signal (for example, user data and the like). Modulation section 1414 generates a modulated transmission signal for each base station apparatus and frequency band represented by the CC information input from communication control section 142, and outputs the generated modulated transmission signal to radio transmission section 1415.

  Radio transmission section 1415 upconverts the modulated transmission signal input from modulation section 1414 from the base frequency band to the radio frequency band, and generates a radio frequency transmission signal. When generating a modulated transmission signal, the wireless transmission unit 1415 up-converts the center frequency from the base frequency to the center frequency of the band for each band represented by the CC information input from the communication control unit 142. This CC information represents an uplink CC that transmits a signal to the base station apparatus. Radio transmission section 1415 outputs the generated radio frequency transmission signal to antenna section 1411.

  The communication control unit 142 includes a communication measurement unit 1421, a synchronization processing unit 1422, and a bandwidth management unit 1423.

The communication measurement unit 1421 measures a communication amount and communication quality related to communication with each connection destination base station apparatus (for example, the HeNB 13-1) based on the reception signal input from the demodulation unit 1413. For example, the communication measuring unit 1421 calculates the amount of information (communication amount) per unit time (for example, 10 ms) of the received signal.
The communication measuring unit 1421 determines whether the calculated communication amount is greater than a predetermined communication amount (for example, r times the communication amount that can be transmitted by the CC being used, where r is a positive real number smaller than 1). Judge. When it is determined that the communication amount is larger than the predetermined communication amount, the communication measurement unit 1421 generates a CA determination signal indicating that it is determined that CA is required, and outputs the generated CA determination signal to the synchronization processing unit 1422. .

  The communication measurement unit 1421 extracts a synchronization signal from the received signal received from the base station apparatus (for example, in the frequency band B from the HeNB 13-1), and generates quality information based on the extracted synchronization signal. The quality information includes, for example, information indicating a signal to interference noise ratio (SINR, Signal to Interference Ratio). The communication measurement unit 1421 outputs the generated quality information to the modulation unit 1414 as a transmission signal to the connected base station apparatus.

  When the CA determination signal is input from the communication measurement unit 1421, the synchronization processing unit 1422 extracts the synchronization signal from the reception signal input from the demodulation unit 1413, and the UE 14 is located in the cell based on the extracted synchronization signal. The eNB 12 that can use the new CC is detected. The new CC is a CC different from the CC (for example, the band B) used for transmitting / receiving user data to / from the communicating base station apparatus. Here, the synchronization processing unit 1422 determines that the base station identification information (cell ID) represented by the extracted synchronization signal is base station identification information representing the eNB 12 (eNB search, cell search). The synchronization processing unit 1422 extracts system information from the received signal input from the demodulation unit 1413. The synchronization processing unit 1422 reads, as a new CC (for example, band A), a CC that is not used for transmission / reception among the CCs related to the eNB among the extracted system information (band detection). Hereinafter, the description may be made assuming that the new CC is the band A and the eNB that can use the CC is the eNB 12. In the present embodiment, the new CC may be a band other than the band A, and the eNB related to the CC is not limited to the eNB 12.

The synchronization processing unit 1422 generates CA request information indicating that a CA is requested to the eNB 12 that can use the CC of the new band A. Synchronization processing section 1422 outputs CA request information to modulation section 1414 as a transmission signal to HeNB 13-1.
The synchronization processing unit 1422 may generate a PI (Proximity Indicator) as an example of CA request information. The PI is information (location information) indicating that the UE 14 is in the cell 32 of the eNB 12 that performs communication using the CC of the band A, for example. The PI generated by the synchronization processing unit 1422 is, for example, entering proximity indication, that is, information indicating that the UE 14 has entered the cell 32. The synchronization processing unit 1422 outputs the generated PI to the modulation unit 1414 as a transmission signal to the HeNB 13-1.

  The synchronization processing unit 1422 performs synchronization processing with the eNB 12 when the CA preparation notification information is input from the demodulation unit 1413 as a reception signal in the band B from the HeNB 13-1. The CA preparation notification information is information for notifying that the HeNB 13-1 and the eNB 12 perform processing related to CA preparation. In the synchronization processing, the synchronization processing unit 1422 detects the PSS from the synchronization signal received in the band A, for example, and detects the relative position (offset amount) of the SSS from the PSS. The synchronization processing unit 1422 detects the SSS at the detected position, and identifies the range of each frame in the received signal from the eNB 12, that is, the frame timing, based on the detected position of the SSS. After the synchronization processing is completed, the synchronization processing unit 1422 generates CA preparation confirmation information (ACK), and outputs the generated CA preparation confirmation information to the modulation unit 1414 as a transmission signal to the HeNB 13-1. The CA preparation confirmation information is information indicating that the CA preparation process has been completed. The synchronization processing unit 1422 generates a synchronization processing completion signal indicating that the synchronization processing has been completed for the band A, and outputs the generated synchronization processing completion signal to the band management unit 1423.

  Band management section 1423 generates CC information representing a band for communicating with the base station apparatus. Band management section 1423 outputs CC information related to the downlink to radio reception section 1412, and outputs CC information related to the uplink to radio transmission section 1415. Here, the bandwidth management unit 1423 generates CC information representing the bandwidth A to the eNB 12 based on the synchronization processing completion signal input from the synchronization processing unit 1422. Band management section 1423 outputs the generated CC information to radio reception section 1412 and radio transmission section 1415. Thereby, UE14 can receive user data from eNB12 using CC of zone | band A, and can transmit now to eNB12. The band management unit 1423 generates CA start information indicating that CA to the eNB 12 has started using the CC of band A. Band management section 1423 outputs CA start information generated as a transmission signal to eNB 12 to modulation section 1414.

  The data processing unit 143 is a processing unit that performs processing on user data. The data processing unit 143 executes applications such as voice communication and data communication, for example. The data processing unit 143 extracts reception user data from the reception signal input from the demodulation unit 1413, and performs processing related to the extracted reception user data. The data processing unit 143 outputs the transmission user data to the modulation unit 1414 as a transmission signal.

(Configuration of HeNB)
Next, the configuration of the HeNB 13 according to the present embodiment will be described.
FIG. 6 is a schematic diagram illustrating the configuration of the HeNB 13 according to the present embodiment.
The HeNB 13 includes a transmission / reception unit 131, a communication control unit 132, and a data processing unit 133.

  The transmission / reception unit 131 includes an antenna unit 1311, a wireless reception unit 1312, a demodulation unit 1313, a modulation unit 1314, and a wireless transmission unit 1315.

The antenna unit 1311 outputs the radio frequency reception signal received from the UE 14 to the radio reception unit 1312. The antenna unit 1311 transmits the radio frequency transmission signal input from the radio transmission unit 1315 to the UE 14 as a radio wave.
The radio reception unit 1312 generates a modulated reception signal by down-converting the radio frequency reception signal input from the antenna unit 1311 to the base frequency band. The processing performed by the wireless reception unit 1312 is the same as the processing performed by the wireless reception unit 1412. The wireless reception unit 1312 outputs the generated modulated reception signal to the demodulation unit 1313.
The demodulation unit 1313 demodulates the modulated reception signal input from the wireless reception unit 1312 and generates a reception signal. The demodulation unit 1313 outputs the generated reception signal to the communication control unit 132 and the data processing unit 133. The processing performed by the demodulation unit 1313 is the same as that of the demodulation unit 1413.

The modulation unit 1314 modulates the transmission signal input from the communication control unit 132 and the data processing unit 133 to generate a modulated transmission signal. The process performed by the modulation unit 1314 is the same as that of the modulation unit 1414. Modulation section 1314 outputs the generated modulated transmission signal to radio transmission section 1315.
Radio transmission section 1315 upconverts the modulated transmission signal input from modulation section 1314 from the base frequency band to the radio frequency band, and generates a radio frequency transmission signal. The process performed by the wireless transmission unit 1315 is the same as that of the wireless transmission unit 1415. Radio transmission section 1315 outputs the generated radio frequency transmission signal to antenna section 1311.

  In addition, the transmission / reception part 131 transmits the transmission signal to eNB12 or MME15 input from the communication control part 132 or the data processing part 133 to eNB12 or MME15 through a backbone network (not shown). The transmission / reception unit 131 outputs a reception signal received from the eNB 12 or the MME 15 through the backbone network to the communication control unit 132 or the data processing unit 133 (not shown).

The communication control unit 132 includes a preparation processing unit 1321 and a bandwidth management unit 1322.
When the CA request information is input from the demodulation unit 1313 as a reception signal from the UE 14, the preparation processing unit 1321 communicates with the UE 14 using the CC (eg, band A) indicated by the CA request information. CA preparation processing is performed between them. The preparation processing unit 1321 outputs a communication path setting request signal indicating that a communication path between the eNB 12 and the counterpart device is requested to the transmission / reception unit 131 as a transmission signal to the MME 15. The preparation processing unit 1321 identifies the eNB 12 using the CA request information. A communication channel setting confirmation signal corresponding to the above-described communication channel setting request signal is input from the transmission / reception unit 131 to the preparation processing unit 1321 as a reception signal from the MME 15. Then, the preparation processing unit 1321 outputs the input CA request information to the transmission / reception unit 131 as a transmission signal to the eNB 12. The preparation processing unit 1321 receives, from the transmission / reception unit 131, the CA preparation notification information for notifying that processing related to preparation for performing communication with the UE 14 using the CC represented by the CA request information is performed. . The preparation processing unit 1321 outputs the input CA preparation notification information to the modulation unit 1314 as a transmission signal to the UE 14. The preparation processing unit 1321 receives CA preparation confirmation information from the demodulation unit 1313 as a reception signal from the UE 14.

  The band management unit 1322 generates CC information indicating a band for communicating with the UE 14. The bandwidth management unit 1322 outputs downlink CC information to the radio transmission unit 1315 and transmits uplink CC information to the radio reception unit 1312. For example, when performing communication by transmitting user data in the band B to the UE 14, the band management unit 1322 generates CC information indicating the band B to the UE 14. Band management section 1322 outputs the generated CC information to radio transmission section 1315.

  The data processing unit 133 is a processing unit that performs processing on user data. For example, the data processing unit 133 extracts user data from the reception signal input from the demodulation unit 1313, and transmits the extracted user data to the counterpart device via the transmission / reception unit 131. The data processing unit 133 outputs user data received from the counterpart device to the modulation unit 1314 as a transmission signal.

(Configuration of eNB)
Next, the configuration of the eNB 12 according to the present embodiment will be described.
FIG. 7 is a schematic diagram illustrating the configuration of the eNB 12 according to the present embodiment.
The eNB 12 includes a transmission / reception unit 121, a communication control unit 122, and a data processing unit 123.

The transmission / reception unit 121 includes an antenna unit 1211, a wireless reception unit 1212, a demodulation unit 1213, a modulation unit 1214, and a wireless transmission unit 1215.
The configuration and processing of the antenna unit 1211, the wireless reception unit 1212, the demodulation unit 1213, the modulation unit 1214, and the wireless transmission unit 1215 are the same as the above-described antenna unit 1311, wireless reception unit 1312, demodulation unit 1313, modulation unit 1314, and wireless transmission. The configuration and processing of the unit 1315 are the same.
The configuration and processing of the data processing unit 123 are the same as the configuration and processing of the data processing unit 133 described above.

  The communication control unit 122 includes a preparation processing unit 1221, a synchronization processing unit 1222, and a bandwidth management unit 1223.

The CA request information is input from the demodulation unit 1213 to the preparation processing unit 1221 as a reception signal from the HeNB 13. The preparation processing unit 1221 outputs the input CA request information to the synchronization processing unit 1222. Then, the preparation processing unit 1221 generates CA preparation notification information, and outputs the generated CA preparation notification information to the modulation unit 1214 as a transmission signal to the HeNB 13.
Note that the preparation processing unit 1221 outputs a communication path setting request signal for requesting setting of a communication path between the own device (eNB 12) and the counterpart device to the transmission / reception unit 121 as a transmission signal to the MME 15. Good. In this case, after the communication path setting confirmation signal is input as the reception signal from the MME 15 from the transmission / reception unit 121, the CA request information and the CA preparation notification information are output. In that case, the preparation processing unit 1321 of the HeNB 13 may omit the process of outputting the communication path setting confirmation signal.

  The synchronization processing unit 1222 performs synchronization processing with the UE 14 after the CA request information is input from the preparation processing unit 1221. The band related to the synchronization process is a CC (for example, band A) represented by the CA request information. The synchronization processing unit 1222 receives the reception signal from the UE 14 received using the CC from the demodulation unit 1213 and extracts the DMRS from the input reception signal. The synchronization processing unit 1222 calculates a delay time that takes the maximum value (peak value) of the cross-correlation between the DMRS stored in advance and the extracted DMRS. The synchronization processing unit 1222 identifies the range of each frame in the received signal from the UE 14, that is, the frame timing, based on the calculated delay time. The synchronization processing unit 1222 outputs a synchronization processing completion signal indicating that the synchronization processing is completed to the band management unit 1223 after the synchronization processing is completed.

  The band management unit 1223 generates CC information indicating a band for communicating with the UE 14. Band management section 1223 outputs CC information related to the downlink to radio transmission section 1215 and transmits CC information related to the uplink to radio reception section 1212. When CA start information is input from the demodulator 1213 as a received signal from the UE 14, the band management unit 1223 generates CC information (for example, band A to the UE 14) represented by the CA start information. The bandwidth management unit 1223 outputs the generated CC information to the wireless reception unit 1212 and the wireless transmission unit 1215. As a result, the eNB 12 can transmit user data to the UE 14 using the CC of the band A and receive the user data from the UE 14.

  Band management section 1223 may generate CC information after the synchronization processing completion signal is input from synchronization processing section 1222, and output the generated CC information to radio reception section 1212 and radio transmission section 1215. In that case, the band management unit 1223 generates CA start information, and outputs the generated CA start information to the modulation unit 1214 as a transmission signal to the UE 14. Thereby, eNB12 transmits CA start information to UE14. In this case, the UE 14 can omit transmitting the CA start information to the eNB 12.

  The data processing unit 123 is a processing unit that performs processing on user data. The configuration and processing of the data processing unit 123 is the same as that of the data processing unit 133.

(CA processing sequence)
Next, communication processing according to the present embodiment will be described.
FIG. 8 is a sequence diagram illustrating communication processing according to the present embodiment.
Here, communication is initially performed between the HeNB 13-1 and the UE 14 using the CC in the band B as the PCC. FIG. 8 shows a process until communication is performed between the eNB 12 and the UE 14 using the CC of the band A as the SCC. Hereinafter, transmission / reception of information between each base station apparatus and the UE will be mainly described, and processing of the transmission / reception unit 121 and the like will be omitted.

(Step S101) The communication measurement unit 1421 of the UE 14 measures the communication amount of the received signal from the HeNB 13-1, and determines whether the CA is necessary based on the measured communication amount. When it is determined that CA is necessary, the synchronization processing unit 1422 of the UE 14 searches for an eNB that is different from the band B and can use the CC of the unused band A based on the synchronization signal included in the received signal from the eNB 12. To do. Thereafter, the process proceeds to step S102.

(Step S102) The synchronization processing unit 1422 of the UE 14 generates a PI as CA request information for the eNB 12 detected in Step S101, and transmits the generated PI to the HeNB 13-1 using the CC of the band B. Thereafter, the process proceeds to step S103.

(Step S103) After receiving the CA request information from the UE 14, the preparation processing unit 1321 of the HeNB 13-1 performs CA preparation processing. For example, the preparation processing unit 1321 transmits a communication path setting request signal indicating that a communication path between the eNB 12 and the counterpart apparatus represented by the received CA request information is set to the MME 15 (not shown). The preparation processing unit 1321 transmits the received CA request information to the eNB 12 after receiving the communication path setting confirmation signal from the MME 15.
The preparation processing unit 1221 of the eNB 12 outputs the CA request information received from the HeNB 13-1 to the synchronization processing unit 1222. The preparation process part 1221 produces | generates CA preparation notification information, and transmits produced | generated CA preparation notification information to HeNB13-1. Thereafter, the process proceeds to step S104.

(Step S104) The preparation processing unit 1321 of the HeNB 13-1 transmits the CA preparation notification information received from the eNB 12 to the UE 14. Thereafter, the process proceeds to step S105.
(Step S105) After receiving the CA preparation notification information from the eNB 12, the synchronization processing unit 1422 of the UE 14 performs a synchronization process on the CC in the band A with the eNB 12. After the CA request information is input from the preparation processing unit 1221, the synchronization processing unit 1222 of the eNB 12 performs synchronization processing on the CC in the band A with the UE 14. Thereafter, the process proceeds to step S106.

(Step S106) The synchronization processing unit 1422 of the UE 14 generates a synchronization processing completion signal, and outputs the generated synchronization processing completion signal to the band management unit 1423. The synchronization processing unit 1422 of the UE 14 generates CA preparation confirmation information (ACK) and transmits the generated CA preparation confirmation information to the HeNB 13-1. The CA preparation confirmation information is input from the UE 14 to the preparation processing unit 1321 of the HeNB 13-1. Thereafter, the process proceeds to step S107.
(Step S107) After the synchronization processing management signal is input from the synchronization processing unit 1422, the band management unit 1423 of the UE 14 generates CC information indicating the band A to the eNB 12, and the generated CC information is transmitted to the radio reception unit 1412 and The data is output to the wireless transmission unit 1415. The band management unit 1423 generates CA start information indicating that CA with the eNB 12 has started using the CC of band A, and transmits the generated CA start information to the eNB 12 using the CC of band A.
The band management unit 1223 of the eNB 12 generates CC information indicating the band A to the UE 14 and outputs the generated CC information to the radio reception unit 1212 and the radio transmission unit 1215. Thereafter, the process proceeds to step S108.

(Step S108) The eNB 12 and the UE 14 start communication using the CC of the band A. That is, the UE 14 receives user data from the counterpart device as a reception signal via the eNB 12 using the CC in the band A, and transmits user data to the counterpart device as a transmission signal. Thereafter, the process ends.

Next, the eNB search process in step S101 described above will be described.
FIG. 9 is a flowchart showing eNB search processing according to this embodiment.
(Step S1011) The communication measurement unit 1421 of the UE 14 measures the communication amount with the HeNB 13-1 based on the reception signal input from the demodulation unit 1413. Thereafter, the process proceeds to step S1012.
(Step S1012) The communication measuring unit 1421 determines whether or not CA is necessary based on the measured communication volume. For example, when the measured communication volume is larger than the predetermined communication volume, the communication measurement unit 1421 determines that CA is required. The communication measuring unit 1421 determines that the CA is unnecessary when the measured communication volume is equal to or smaller than the predetermined communication volume. If it is determined that CA is required (Y in step S1012), the process proceeds to step S1013. If it is determined that the CA is unnecessary (N in step S1012), the process is terminated.

(Step S1013) The synchronization processing unit 1422 extracts a synchronization signal from the received signal received from the eNB 12. Based on the extracted synchronization signal, the synchronization processing unit 1422 searches for an eNB 12 that has a cell where the UE 14 is located and can use a new CC. When the eNB 12 that can use the new CC can be detected (Y in step S1013), the process proceeds to step S102 (see FIG. 8). When the eNB 12 that can use the new CC cannot be detected (step S1013 N), the process is terminated.

  In addition, the frequency | count of performing the process (eNB search) which detects eNB12 which can use new CC in the synchronous process part 1422 is not restricted to once. The synchronization processing unit 1422 may repeat the eNB search until the eNB 12 is found. However, if the eNB is not found even after repeating the eNB search for a predetermined number of times (for example, three times) or for a predetermined time (for example, 30 seconds), the synchronization processing unit 1422 realizes the CA. Judge that it is not possible. When it is determined that CA cannot be realized, the synchronization processing unit 1422 may repeat the eNB search after a predetermined time (for example, 180 seconds) has elapsed. Further, the synchronization processing unit 1422 may repeat the eNB search at a predetermined time interval (for example, 180 seconds). Also, the synchronization processing unit 1422 may stop the eNB search and output CA impossible information (NACK) to the modulation unit 1414 as a transmission signal to the HeNB 13-1. Note that the synchronization processing unit 1422 may stop the eNB search when the communication amount measured by the communication measurement unit 1421 does not exceed a predetermined communication amount. In that case, the synchronization processing unit 1422 may not output the CA impossibility information.

(Modification 1)
Next, a modification of this embodiment will be described.
In the present modification, the synchronization processing unit 1422 of the UE 14 represents requesting CA with the eNB 12, and generates CA request information (CA request command) represented by a command in a specific format.
FIG. 10 is a sequence diagram illustrating a modification of the communication process according to the present embodiment.
The communication process shown in FIG. 10 is common to the communication process shown in FIG. 8 in that steps S101 and S103-108 are included. However, the communication process illustrated in FIG. 10 includes step S202 instead of step S102 included in the communication process illustrated in FIG. In the communication process shown in FIG. 10, step S202 is executed after step S101.

(Step S202) The synchronization processing unit 1422 of the UE 14 generates CA request information for the eNB 12 discovered in Step S101 and is represented by a command in a specific format. The synchronization processing unit 1422 transmits the generated CA request information to the HeNB 13-1 using the band B CC. Thereafter, the process proceeds to step S103.

(Modification 2)
Next, another modification according to the present embodiment will be described.
In this modification, the CA request information generated by the synchronization processing unit 1422 of the UE 14 is added to other command information and transmitted to the HeNB 13-1. The other command information is, for example, quality information generated by the communication measuring unit 1421. The communication measuring unit 1421 may include communication amount information representing the calculated communication amount in the generated quality information. When the CA request signal is input from the synchronization processing unit 1422, the communication measurement unit 1421 adds the CA request signal to the quality information and outputs the CA request signal to the modulation unit 1414 as an output signal to the HeNB 13-1.

FIG. 11 is a sequence diagram illustrating another modification of the communication process according to the present embodiment.
The communication process shown in FIG. 11 is common to the communication process shown in FIG. 8 in that steps S101 and S103-108 are included. However, the communication process illustrated in FIG. 11 includes step S302 instead of step S102 included in the communication process illustrated in FIG. Here, step S302 is executed after step S101.

(Step S302) The synchronization processing unit 1422 of the UE 14 generates CA request information indicating that a CA is requested with the eNB 12 detected in Step S101, and outputs the generated CA request information to the communication measurement unit 1421. The communication measurement unit 1421 adds the CA request information input from the synchronization processing unit 1422 as a part of the quality information (another command). The communication measuring unit 1421 transmits the CA request information added as part of the quality information to the HeNB 13-1. Thereafter, the process proceeds to step S103.
In step S103, the preparation processing unit 1321 of the HeNB 13-1 extracts CA request information from the quality information received from the UE 14.

(Modification 3)
Next, another modification according to the present embodiment will be described.
In this modification, when the synchronization processing unit 1422 of the UE 14 detects a plurality of eNBs 12 that can use a new CC, one of the detected eNBs 12 (for example, the band A and the eNB 12) is selected. For example, the quality information received from each eNB from the communication measurement unit 1421 is input to the synchronization processing unit 1422, and the eNB 12 (best cell) of the CC having the highest communication quality represented by the input quality information is selected. The synchronization processing unit 1422 generates CA request information for the eNB 12 of the selected CC, and outputs the generated CA request information to the modulation unit 1414 as a transmission signal to the eNB 12.

FIG. 12 is a sequence diagram illustrating another modification of the communication process according to the present embodiment.
The communication process illustrated in FIG. 12 includes steps S101, S401, and S102 to S108. The communication process of FIG. 12 is common to the communication process shown in FIG. 8 in that it includes steps S101-108. However, step S401 is executed after step S101.

(Step S401) When a plurality of eNBs that can use a new CC are detected, the synchronization processing unit 1422 selects one eNB 12 (band A in the example of FIG. 12) having the highest communication quality. For example, the quality information received from each eNB from the communication measurement unit 1421 is input to the synchronization processing unit 1422, and the eNB 12 of the CC having the highest communication quality represented by the input quality information is selected as the best cell. Thereafter, the process proceeds to step S102.
In step S102, the synchronization processing unit 1422 generates the PI of the best cell as CA request information, and transmits the generated PI to the HeNB 13-1.

In the present embodiment, the case has been described as an example where the UE 14 determines whether or not CA is necessary based on the information amount of the downlink received signal, and performs CA for both the downlink and the uplink. In this embodiment, the present invention is not limited to this, and CA may be performed only for the downlink.
In the present embodiment, the UE 14 may determine whether the CA is necessary based on the uplink traffic. Here, the communication measurement unit 1421 communicates with the connection destination base station apparatus (for example, the HeNB 13-1) based on the transmission signal input from the data processing unit 143 instead of the reception signal input from the demodulation unit 1413. The amount of uplink communication related to communication is calculated. In this case, CA may be performed only for the uplink.
Note that the UE 14 may determine whether or not the CA is necessary based on the total communication amount of the uplink communication amount and the downlink communication amount. Here, the communication measurement unit 1421 calculates the total communication amount by adding the downlink communication amount and the uplink communication amount calculated by performing the above-described processing. The communication measuring unit 1421 determines whether or not the CA is necessary based on the calculated total communication amount.

  As described above, the present embodiment relates to the communication system 1 including the eNB 12, the HeNB 13 having the partial region of the cell 32 as the cell 33, and the UE 14. In the present embodiment, the UE 14 communicates with the HeNB 12 using the frequency band B, and the UE 14 generates CA request information indicating that the communication with the eNB 12 is requested using the frequency band A different from the frequency band B. . UE14 transmits the produced | generated request information to HeNB13. Therefore, in this embodiment, since UE14 requests | requires communication with eNB12 which can communicate in UE14 and the frequency band A according to the communication condition in the frequency band B with HeNB13, the utilization efficiency of a frequency resource does not fall.

(Second Embodiment)
Next, a second embodiment according to the present invention will be described. Portions having the same configuration and processing as those of the first embodiment are denoted by the same reference numerals.
The communication system 2 according to the present embodiment relates to a communication system including the eNB 12, HeNBs 23-1 to 23-3 having a partial region of the cell 32 as a cell 33, and the UE 14. Hereinafter, the HeNBs 23-1 to 23-3 may be collectively referred to as the HeNB 23. The HeNB 23 communicates with the UE 14 using the band B, generates CA request information indicating that communication between the eNB 12 and the UE 14 is requested using the band A different from the band B, and transmits the CA request information to the UE 14. .

In the present embodiment, the HeNB is configured to determine whether or not CA is necessary.
FIG. 13 is a schematic diagram illustrating the communication system 2 according to the present embodiment.
The communication system 2 according to the present embodiment includes a RAN 11, an eNB 12, HeNBs 23-1 to 23-3, a UE 14, and an MME 15. That is, the communication system 2 is common to the communication system 1 (see FIG. 4) in that it includes the RAN 11, the eNB 12, the UE 14, and the MME 15. The communication system 2 differs from the communication system 1 in that HeNBs 23-1 to 23-3 are provided instead of the HeNBs 13-1 to 13-3.

FIG. 14 is a schematic diagram illustrating the configuration of the HeNB 23 according to the present embodiment.
The HeNB 23 includes a transmission / reception unit 131, a communication control unit 232, and a data processing unit 133. The communication control unit 232 includes a communication processing unit 2323 in addition to the preparation processing unit 1321 and the bandwidth management unit 1322.
The communication measurement unit 2323 determines whether or not CA is necessary based on the communication amount of the received signal received from the UE 14. The communication measurement unit 2323 measures a communication amount related to communication with the connection destination UE 14 based on the reception signal input from the demodulation unit 1213. The communication measuring unit 2323 determines whether the calculated communication amount is larger than a predetermined communication amount. When it is determined that the communication amount is larger than the predetermined communication amount, the communication measurement unit 2323 generates CA request information. The generated CA request information indicates that the HeNB 23 requests communication between the eNB 12 and the UE 14 using a CC in a new band A different from the CC band B used for communication with the UE 14. Such communication is related to transmission / reception of user data between the UE 14 and the counterpart device.
The communication measurement unit 2323 outputs the generated CA request information to the modulation unit 1314 as a transmission signal to the UE 14.

CA request information is input from the demodulator 1413 to the synchronization processor 1422 of the UE 14 as a received signal from the HeNB 23. The synchronization processing unit 1422 performs the above-described eNB search after the CA request information is input. After completing the eNB search, the synchronization processing unit 1422 generates CA request confirmation information (ACK) indicating that the CA request information has been received, and transmits the generated CA request confirmation information to the modulation unit 1414 as a transmission signal to the HeNB 23. Output.
Thereafter, CA request confirmation information is input from the demodulation unit 1313 to the preparation processing unit 1321 of the HeNB 23 as a reception signal from the UE 14. Thereafter, the preparation processing unit 1321 performs the CA preparation processing described above.

Next, communication processing according to the present embodiment will be described.
FIG. 15 is a sequence diagram illustrating communication processing according to the present embodiment.
The communication process shown in FIG. 15 includes steps S501, S101, S502, and S103-S108. The communication process of FIG. 15 is common to the communication process shown in FIG. 8 in that steps S101 and S103-108 are included. However, in the communication process of FIG. 15, step S101 is executed after step S501, and step S502 is executed after step S101.

(Step S501) The communication measurement unit 2323 determines whether or not the CA is necessary based on the communication amount of the received signal received from the UE 14. When it is determined that the communication amount is larger than the predetermined communication amount, the communication measurement unit 2323 generates CA request information and transmits the generated CA request information to the UE 14. Then, it progresses to step S101. In step S101, the communication measurement unit 1421 of the UE 14 omits the measurement of the traffic volume, and the communication measurement unit 1421 of the UE 14 omits the process related to the traffic volume measurement and the CA necessity determination (see FIG. 9, steps S1011 and S1012). Also good.

(Step S502) After completing the eNB search (see FIG. 9, step S1013), the synchronization processing unit 1422 of the UE 14 generates CA request confirmation information, and transmits the generated CA request confirmation information to the HeNB 23-1. The preparation processing unit 1321 of the HeNB 23-1 receives CA request confirmation information from the UE 14. Thereafter, the process proceeds to step S103.

  In the present embodiment, as in the third modification of the first embodiment described above, in step S101, when the synchronization processing unit 1422 detects a plurality of eNBs 12 that can use a new CC, the communication quality One eNB 12 having the highest CC may be selected.

In the present embodiment, the case has been described by way of example in which the HeNB 23 determines whether or not CA is necessary based on the information amount of the uplink received signal and performs CA for both uplink and downlink. In this embodiment, the present invention is not limited to this, and CA may be performed only for the uplink.
In the present embodiment, the HeNB 23 may determine whether or not CA is necessary based on the downlink traffic. Here, the communication measurement unit 2323 determines the downlink communication amount related to the communication with the UE 14 as the connection destination based on the reception signal input from the data processing unit 133 instead of the reception signal input from the demodulation unit 1313. calculate. In this case, CA may be performed only for the downlink.
Note that the HeNB 23 may determine whether or not the CA is necessary based on the total communication amount of the uplink communication amount and the downlink communication amount. Here, the communication measurement unit 2323 calculates the total communication amount by adding the downlink communication amount and the uplink communication amount calculated by performing the above-described processing. The communication measurement unit 2323 determines whether or not the CA is necessary based on the calculated total communication amount.

  As described above, the present embodiment relates to the communication system 2 including the eNB 12, the HeNB 23 having the partial region of the cell 32 as the cell 33, and the UE 14. In the present embodiment, the HeNB 23 communicates with the UE 14 using the frequency band B, and the HeNB 23 includes CA request information indicating that the HeNB 23 and the UE 14 are requested to communicate using the frequency band A different from the frequency band B. Generate. The HeNB 23 transmits the generated CA request information to the UE 14. Therefore, in this embodiment, since HeNB23 requests | requires communication using UE14 and the frequency band A according to the communication condition in the frequency band B with UE14, the utilization efficiency of a frequency resource does not fall.

Note that a part of the eNB 12, HeNB 13, 23, or UE 14 in the above-described embodiment, for example, the preparation processing unit 1221, the synchronization processing unit 1222, the band management unit 1223, the preparation processing unit 1321, the band management unit 1322, the communication measurement unit 2323 The communication measurement unit 1421, the synchronization processing unit 1422, and the bandwidth management unit 1423 may be realized by a computer. In that case, the program for realizing the control function may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read by a computer system and executed. The “computer system” referred to here is a computer system built in the eNB 12, the HeNB 13, 23, or the UE 14, and includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” is a medium that dynamically holds a program for a short time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, In such a case, a volatile memory inside a computer system serving as a server or a client may be included and a program that holds a program for a certain period of time. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.
Moreover, you may implement | achieve part or all of eNB12, HeNB13, 23, or UE14 in embodiment mentioned above as integrated circuits, such as LSI (Large Scale Integration). Each functional block of the eNB 12, the HeNB 13, 23, and the UE 14 may be individually converted into a processor, or a part or all of them may be integrated into a processor. Further, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. Further, in the case where an integrated circuit technology that replaces LSI appears due to progress in semiconductor technology, an integrated circuit based on the technology may be used.

  As described above, the embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to the above, and various design changes and the like can be made without departing from the scope of the present invention. It is possible to

1, 2, ... communication system,
11 ... RAN, 12 ... eNB,
121 ... Transmission / reception unit, 1211 ... Antenna unit, 1212 ... Radio reception unit, 1213 ... Demodulation unit, 1214 ... Modulation unit, 1215 ... Radio transmission unit,
122, 222 ... communication control unit, 1221 ... preparation processing unit, 1222 ... synchronization processing unit,
1223 ... Band management unit, 123 ... Data processing unit 13 (13-1 to 13-3), 23 (23-1 to 23-3) ... HeNB,
131: Transmission / reception unit, 1311: Antenna unit, 1312 ... Radio reception unit, 1313 ... Demodulation unit, 1314 ... Modulation unit, 1315 ... Radio transmission unit,
132 ... Communication control unit, 1321 ... Preparation processing unit, 1322 ... Band management unit,
2323 ... Communication measuring unit, 133 ... Data processing unit,
14 ... UE,
141 ... Transmitter / receiver, 1411 ... Antenna, 1412 ... Radio receiver, 1413 ... Demodulator, 1414 ... Modulator, 1415 ... Radio transmitter,
142 ... communication control unit, 1421 ... communication measurement unit, 1422 ... synchronization processing unit,
1423 ... Bandwidth management unit, 143 ... Data processing unit,
15 ... MME

Claims (11)

A communication system comprising a macro cell base station device, a small base station device having a partial cell area of the macro cell base station device as a cell, and a mobile station device,
The mobile station device
A transceiver that communicates with the small base station device using a first frequency band;
Communication for generating request information indicating that communication with the small base station apparatus is requested using a second frequency band different from the first frequency band, and transmitting the request information to the small base station apparatus A control unit;
A communication system comprising: The mobile station device
A communication measuring unit that measures the communication amount with the small base station device,
The communication system according to claim 1, wherein the communication control unit determines whether to perform communication using the second frequency band based on a communication amount measured by the communication measurement unit. The communication control unit
The communication system according to claim 1 or 2, wherein a macro cell base station apparatus capable of communication using the second frequency band is searched.   4. The communication system according to claim 3, wherein the communication control unit transmits, as the request information, location information indicating presence in a cell of the searched macro cell base station device. 5.   The communication system according to claim 1, wherein the communication control unit adds the request information to measurement information related to communication with the small base station apparatus and transmits the measurement information to the small base station apparatus.   The communication system according to claim 3, wherein the communication control unit selects a macro cell base station apparatus having the highest communication quality when detecting a plurality of communicable macro cell base station apparatuses. A communication system comprising a macro cell base station device, a small base station device having a partial cell area of the macro cell base station device as a cell, and a mobile station device,
The small base station device is:
A transmission / reception unit that communicates with the mobile station apparatus using a first frequency band;
Generating request information indicating that communication between the macro cell base station apparatus and the mobile station apparatus is requested using a second frequency band different from the first frequency band, and the request information is transmitted to the mobile station apparatus; A communication control unit for transmitting to
A communication system comprising: A transceiver that communicates with the small base station device using the first frequency band;
Request information indicating requesting communication with a macro base station apparatus using the second frequency band different from the first frequency band as a part of the cell of the small base station apparatus. A communication control unit for generating and transmitting the request information to the small base station device;
A mobile station apparatus comprising: A transceiver that communicates with the mobile station device using the first frequency band;
Request information representing requesting communication between a macro base station apparatus using a second frequency band different from the first frequency band as a cell and a partial area of its own cell and the mobile station apparatus And a communication control unit for transmitting the request information to the mobile station device,
A small base station apparatus comprising: A communication method in a mobile station device,
The mobile station apparatus communicates with a small base station apparatus using a first frequency band;
The mobile station apparatus requests communication with a macro base station apparatus that uses a cell of the small base station apparatus as a part of its own cell using a second frequency band different from the first frequency band. Generating request information indicating that, and transmitting the request information to the small base station device,
A communication method characterized by comprising: A communication method in a small base station device,
The small base station device communicates with the mobile station device using the first frequency band;
The small base station apparatus uses a second frequency band different from the first frequency band to perform communication between the macro base station apparatus having a partial area of its own cell as a cell and the mobile station apparatus. Generating request information indicating requesting, and transmitting the request information to the mobile station device;
A communication method characterized by comprising:

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