JP7386254B2 - Relay device, relay method, and relay system - Google Patents

Description

The present invention relates to a relay technology that relays communication between a terminal device and a macro cell base station.

In Release 8 of 3GPP (The 3rd Generation Partnership Project ), which formulates standards related to mobile communications, LTE ( Long Term Evolution ) is defined as a communication standard and is in operation (non-patent document 1). ). In mobile communication systems compliant with LTE and other communication standards, in order to improve the coverage of user equipment (UE), small cells (macro-cells), which have a smaller coverage area than macro - cell base stations, are used to improve the coverage of user equipment (UE). Small-cell) base stations are used. A small cell base station connects to a terminal device via an access (AC: Access Link) communication path. Small cell base stations also connect to core networks operated by mobile network operators ( MNOs ) via backhaul (BH: Backhaul Link) communication paths. As a technology related to such small cell base stations, a relay device that allocates different frequency bands to an access channel and a backhaul channel has been devised (Patent Document 1). Furthermore, a standard for sharing a wireless communication channel among multiple mobile communication networks has also been proposed (Non-Patent Document 2).

http://www.3gpp.org/technologies/keywords-acronyms/98-lte http://www.3gpp.org/news-events/3gpp-news/1592-gush

Japanese Patent Application Publication No. 2016-171536

Mobile communication systems such as those described in prior art documents use relay devices that are easier to install than base stations to expand the coverage area of the entire system.

However, the cells formed by the relay device have a narrow frequency band in the relay device, communication congestion between the terminal device and the backhaul, generation of weak electricity, etc., compared to the cells of nearby base stations. Throughput was sometimes low.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a relay device, a relay method, and a relay system that can suppress a decrease in throughput.

A relay device according to one aspect of the present invention is a relay device that relays communication between a donor cell base station and a terminal device using a first cell, and includes cell identification information that associates a cell with a base station forming the cell. a management unit that manages registration of the second cell, the management unit that registers cell identification information of a second cell different from the first cell; a notification unit that notifies the terminal device of the cell identification information of the second cell; a first acquisition unit that acquires synchronization information for synchronizing communication using a second cell between a base station and a terminal device associated with the cell identification information of the donor cell base station; A timing control unit that controls frame timing when relaying communication to a terminal device.

A relay method according to one aspect of the present invention is a relay method that uses a first cell to relay communication between a donor cell base station and a terminal device, and includes cell identification information that associates a cell with a base station forming the cell. a step of registering cell identification information of a second cell different from the first cell, a step of notifying the cell identification information of the second cell to the terminal device, and a step of managing the registration of the cell identification information of the second cell. a step of acquiring synchronization information for synchronizing communication using a second cell between a base station and a terminal device associated with the information; and a step of controlling communication from the donor cell base station to the terminal device based on the synchronization information. and controlling the timing of frames when relaying.

A relay system according to one aspect of the present invention includes a relay device that relays communication between a donor cell base station and a terminal device using a first cell, and a cell formed by the base station and a relay device that relays communication between a donor cell base station and a terminal device using a first cell. A base station management device that manages cell identification information that associates a base station with a base station and location information that indicates a location of the base station, the base station management device managing cell identification information that associates a base station with a base station, and that responds to a request from a relay device by a base station management device that responds with cell identification information of a cell to be formed; the relay device is a management unit that manages registration of cell identification information; A management unit for registering, a notification unit for notifying the terminal device of cell identification information of the second cell, and communication using the second cell between a base station associated with the cell identification information of the second cell and the terminal device. A management unit includes an acquisition unit that acquires synchronization information for synchronization, and a timing control unit that controls frame timing when relaying communication from the donor cell base station to the terminal device based on the synchronization information. , the cell identification information included in the response from the base station management device is registered as the cell identification information of the second cell.

A relay system according to one aspect of the present invention includes a relay device that uses a first cell to relay communication between a donor cell base station and a terminal device, and provides reference time information indicating a reference time to each of a plurality of base stations. a time management device; the relay device is a management unit that manages registration of cell identification information that associates a cell with a base station forming the cell; a management unit that registers the cell identification information of the second cell, a notification unit that notifies the terminal device of the cell identification information of the second cell, and communication using the second cell between the base station associated with the cell identification information of the second cell and the terminal device. an acquisition unit that acquires synchronization information for synchronizing with the terminal device; and a timing control unit that controls frame timing when relaying communication from the donor cell base station to the terminal device based on the synchronization information. acquires reference time information as synchronization information, and the timing control unit receives information from the donor cell base station based on the deviation time from the reference time and the propagation delay time in communication with the time management device, which are calculated from the reference time information. To advance the frame timing when relaying communication to a terminal device.

According to the present invention, reduction in throughput can be suppressed.

FIG. 1 is a schematic diagram showing an example of the configuration of a mobile communication system according to the first embodiment. FIG. 2 is a schematic diagram showing a modified example of the configuration of the mobile communication system in the first embodiment. FIG. 3 is a configuration diagram illustrating the hardware configuration of the relay device centering on the division/integration unit. FIG. 4 is a schematic diagram illustrating the operation of the backhaul communication unit. FIG. 5 is a schematic diagram illustrating the basic operation of the division and integration section. FIG. 6 is a flowchart illustrating the general operation of carrier aggregation by the relay device. FIG. 7 is a configuration diagram illustrating the software configuration of the control unit. FIG. 8 is a schematic diagram illustrating an example of the first method of selecting the second cell. FIG. 9 is a schematic diagram illustrating another example of the first method of selecting the second cell. FIG. 10 is a schematic diagram illustrating a second method of selecting a second cell. FIG. 11 is a schematic diagram illustrating a third method of selecting the second cell. FIG. 12 is a schematic diagram illustrating an example of the fourth method of selecting the second cell. FIG. 13 is a schematic diagram illustrating another example of the fourth method of selecting the second cell. FIG. 14 is a schematic diagram illustrating an example of the operation of the synchronization information acquisition section. FIG. 15 is a schematic diagram illustrating another example of the operation of the synchronization information acquisition section. FIG. 16 is a schematic diagram illustrating still another example of the operation of the synchronization information acquisition unit. FIG. 17 is a schematic diagram schematically showing the configuration of a relay system in the second embodiment. FIG. 18 is a configuration diagram illustrating the software configuration of the control unit. FIG. 19 is a schematic diagram illustrating the operation of the synchronization information acquisition section. FIG. 20 is a schematic diagram schematically showing the configuration of a relay system in the third embodiment. FIG. 21 is a configuration diagram illustrating the software configuration of the control section. FIG. 22 is a schematic diagram illustrating the operation of the timing control section.

Embodiments of the present invention will be described below. In the description of the drawings below, the same or similar parts are represented by the same or similar symbols. However, the drawings are schematic. Therefore, specific dimensions, etc. should be determined in reference to the following description. Furthermore, it goes without saying that the drawings include portions with different dimensional relationships and ratios. Furthermore, the technical scope of the present invention should not be interpreted as being limited to the embodiments.

[First embodiment]
<Relay device>
A first embodiment of the present invention relates to a basic form of a relay device that can be simultaneously connected to mobile communication networks MN ( M obile Network Operator) operated by different mobile communication carriers (MNO: M obile Network Operator ). It is something. In the following description, different mobile communication carriers will be identified by lowercase letters of the alphabet. For example, device XY, which is a system or configuration associated with mobile communication carrier a, is written as device XYa with a lowercase letter a added thereto.

(Whole system)
FIG. 1 is a schematic diagram showing an example of the configuration of a mobile communication system 100 in the first embodiment. FIG. 2 is a schematic diagram showing a modification of the configuration of the mobile communication system 100 in the first embodiment. As shown in FIG. 1, the mobile communication system 100 includes terminal devices 10a and 10b, a relay device 20, and mobile communication networks MNa and MNb.

The terminal devices 10a and 10b are mobile communication terminals such as smartphones and mobile phones, and are also referred to as UE ( User Equipment ) in the drawings. Hereinafter, if no association with a mobile communication carrier is required, it will simply be referred to as "terminal device 10."

The mobile communication network MNa is an infrastructure system operated by a mobile communication carrier a, and the mobile communication network MNb is an infrastructure system operated by a mobile communication carrier b. In order to simplify the explanation, FIG. 1 illustrates a case where only a mobile communication network MNa managed by a mobile communication carrier a and a mobile communication network MNb managed by a mobile communication carrier b are connected. are doing. However, the mobile communication system 100 may be further connected to a mobile communication network managed by another mobile communication carrier.

Hereinafter, in order to simplify the explanation, it is assumed that the mobile communication network MNa and the mobile communication network MNb have the same configuration. In addition, if there is no particular need to distinguish between mobile communication networks, the numerical codes will be described without lowercase letters.

(Mobile communication network)
The mobile communication network MN comprises a donor-cell base station 30, a macro-cell base station 35, and a core network 70.

The donor cell base station 30 has a configuration as a so-called macro-cell base station. The donor cell base station refers to one of the many macro cell base stations 35 that has established a backhaul communication path with a terminal device or a relay device through a radio bearer. In particular, in the LTE standard, a donor cell base station is sometimes referred to as DeNB ( Donor eNode B ). The donor cell base station 30 and the macro cell base station 35 each operate to form a radio access network ( RAN ) . The donor cell base station 30 is configured not only to establish a backhaul communication path BH with the relay device 20 but also to establish a direct access communication path AC with the terminal device 10. The donor cell base station 30 and the macro cell base station 35 each provide a macro cell, which is a service area with a radius of several hundred meters to more than ten kilometers, by generating relatively high-power radio waves.

The core network 70 includes a first core network 40, a second core network 60, and a virtual base station device 50. The second core network 60 is connected to an external network 80 (public data network). Each of the first core network 40 and the second core network 60 is also called EPC ( Evolved Packet Core ), especially in the LTE standard. FIG. 1 shows an example in which the first core network 40a and the second core network 60a are constructed on the same network EPCa.

The first core network 40 is connected to the donor cell base station 30, and is a network that mainly controls the donor cell base station 30 and manages the establishment and release of the backhaul communication path BH.

The second core network 60 is a network that mainly manages the relay device 20 and the terminal devices 10 directly connected to the relay device 20. For example, the second core network EPC 60 performs location management of the relay device 20, connection control for calling and receiving calls to the terminal device 10 connected to the relay device 20, billing management, and the like.

The virtual base station device 50 is connected to the first core network 40 and the second core network 60. The virtual base station device 50 is provided attached to the relay device 20 and has a configuration as a computer device. The virtual base station device 50 realizes the following functions by executing a predetermined software program.

The functions executed by the virtual base station device 50a include a function of recognizing parameters including the first identification information IDa assigned to the first mobile communication network MNa, and a function of recognizing parameters including the first identification information IDa assigned to the second mobile communication network MNb. This function converts a parameter including the second identification information IDb into a parameter including the first identification information IDa. Similarly, the functions executed by the virtual base station device 50b (not shown) include a function of recognizing parameters including the second identification information IDb assigned to the second mobile communication network MNb, and a function of recognizing parameters including the second identification information IDb assigned to the second mobile communication network MNb. This is a function of converting a parameter including the first identification information IDa assigned to MNa into a parameter including the second identification information IDb. The converted parameters are provided to the relay device 20. The virtual base station device 50 connects the relay device 20, the donor cell base station 30a of the first core network 40a, the macrocell base station 35a of the network EPCa, the donor cell base station 30b, and the macrocell base station 35b on the same EPC. It can be regarded as a base station.

The external network 80 is a broadband network connected via an IP transmission device (such as a router) not shown, and is typically the Internet.

Note that the configuration of the mobile communication network MN described above is an example and is not limited thereto. For example, as shown in FIG. 2, the first core network 40 and the second core network 60 may not be constructed on the same network, but may be different networks. The second core network 60 is connected to the macro cell base station 35. The virtual base station device 50 is installed between the first core network 40 and the second core network 60. In this case, the virtual base station device 50 allows the relay device 20, the macro cell base station 35a, and the macro cell base station 35b of the second core network 60a to be regarded as base stations on the same EPC.

(Relay device)
As shown in FIG. 1, the relay device 20 is a relay device that relays communication between the terminal device 10 and the donor cell base station 30, and includes an access communication section 22, a division and integration section 24, and a backhaul communication section 26. Equipped with In the drawings, the relay device 20 is also referred to as UR ( User Equipment Relay ).

With the above-mentioned components, the relay device 20 of this embodiment is configured to be able to implement the following relay method for relaying communication between the terminal device 10 and the donor cell base station 30.
(1) Step of connecting with one or more terminal devices 10 (access communication unit 22).
(2) Step of establishing each backhaul communication path BH associated with a specific identification information ID with the donor cell base station 30 associated with a specific identification information ID (backhaul communication unit 26).
(3) A step of connecting the terminal device 10 associated with the specific identification information ID to the specific backhaul communication path BH associated with the specific identification information ID (dividing/integrating unit 24).

Hereinafter, the components that execute each step will be specifically explained.
The access communication unit 22 is a communication device that connects to one or more terminal devices 10. In FIG. 1, the access communication unit 22 is commonly connected to a terminal device 10a associated with a mobile communications carrier a and a terminal device 10b associated with a mobile communications carrier b. The access communication unit 22 constructs a small cell, which is a service area with a radius of several meters to several tens of meters, by generating relatively low-power radio waves with respect to the terminal device 10. For this reason, the access communication unit 22 is also called a pico eNB ( evolved Node B ), femto eNB, or home eNB in the LTE standard. In the drawings, the access communication unit 22 is expressed as SC ( Small Cell ). The access communication unit 22 is connected to any of the terminal devices 10 via radio waves in the same frequency band to form an access communication path AC. The access communication unit 22 demodulates the uplink data received from each terminal device 10 and outputs it as a block of packet data in the order of reception. Further, the access communication unit 22 modulates a block of packet data, which is downlink data provided from the division/integration unit 24, with a carrier wave of a common frequency band, and transmits the modulated block through the access channel AC. Both uplink data and downlink data are composed of multiple blocks of packet data. The corresponding mobile communication carrier can be identified by the identification information ID given to each block. The access communication unit 22 is mainly composed of hardware. However, it is also possible to configure the access communication section 22 so that a control section, which will be described later, performs the same function by executing a software program.

Note that among the packets, the packets flowing through the data link layer of the OSI basic reference model are also called frames. In this case, packet data is also called frame data.

The backhaul communication unit 26 establishes each backhaul communication path BH associated with the specific identification information ID with the donor cell base station 30 associated with the specific identification information. In FIG. 1, the backhaul communication unit 26a establishes a backhaul communication path BHa with the donor cell base station 30a associated with identification information IDa that identifies the mobile communication carrier a. Further, the backhaul communication unit 26b establishes a backhaul communication path BHb with the donor cell base station 30b associated with the identification information IDb identifying the mobile communication carrier b. Uplink data and downlink data transmitted and received via the backhaul communication path BH are radio waves modulated with a carrier wave in a frequency band designated by the corresponding donor cell base station 30, respectively. The backhaul communication unit 26 is also called customer premises equipment ( CPE ). The backhaul communication unit 26 is mainly composed of hardware. However, it is also possible to configure the backhaul communication section 26 so that a control section, which will be described later, performs the same function by executing a software program.

The backhaul communication path BH formed by the backhaul communication unit 26 is a path for transmitting packet data via an antenna. The packet data may be modulated with a carrier wave in a predetermined frequency band according to a predetermined modulation method according to a communication standard.

A splitting and combining unit ( SCU ) 24 connects the terminal device 10 associated with a specific identification information ID to a specific backhaul communication path BH associated with a specific identification information ID. is configured to do so. The division and integration unit 24 is functionally realized, for example, by operating predetermined hardware using software.

Next, the hardware configuration of the relay device 20 will be described with reference to FIG. 3. FIG. 3 is a configuration diagram illustrating the hardware configuration of the relay device 20 centering on the division/integration unit 24. As shown in FIG. 3, the division/integration section 24 includes a control section 200, a storage section 204, and interface circuits 206 and 210.

The control unit 200 includes a processor 201 such as a CPU ( Central Processing Unit ), an ASIC ( Application Specific Integrated Circuit ), an FPGA ( Field Programmable Gate Array ), and a ROM ( Read Only memory ), RAM ( Random Access Memory ), etc. The control unit 200 realizes the functions of the division and integration unit 24 by the processor 201 executing a computer software program stored in the memory 202. However, it is also possible to configure the division/integration unit 24 only by hardware so as to perform the same function.

The interface circuit 206 is a connection means for transmitting and receiving integrated data CD to and from the access communication section 22. The interface circuit 210 is a connection means for transmitting and receiving divided data SD to and from each backhaul communication section 26.

The storage unit 204 is a memory configured such that data is read out in the order in which it is written. Specifically, in the uplink, the storage unit 204 sequentially stores packet data that the access communication unit 22 receives from the terminal device 10 via the antenna 222 and supplies to the internal bus via the interface circuit 206. The packet data sequentially read from the storage unit 204 under the control of the control unit 200 is sent to the backhaul communication unit via the interface circuit 210 associated with the identification information ID in block units associated with the identification information ID. 26 and is transmitted from the antenna 262 toward the donor cell base station 30. Further, in the downlink, the storage unit 204 stores the packet data that the backhaul communication unit 26 receives from the antenna 262 and supplies to the internal bus via the interface circuit 210 in the order in which it is received. The packet data sequentially read out from the storage unit 204 under the control of the control unit 200 is transferred to the access communication unit 22 via the interface circuit 206 as an integrated data CD in blocks associated with the identification information ID. 222 to the terminal device 10.

Note that the block diagram shown in FIG. 3 is merely an example, and it is also possible to configure a different configuration to perform the same function. For example, in the above block diagram, uplink data and downlink data are supplied to the internal bus managed by the control unit 200, but the access communication unit 22 and backhaul communication unit 26 may be directly connected via a buffer memory. , the control unit 200 can also be configured to perform only the overall control function. Such a configuration is appropriate when the communication speed is relatively high or the traffic capacity is large.

Next, the functions of the backhaul communication section 26 will be explained with reference to FIG. 4. FIG. 4 is a schematic diagram illustrating the operation of the backhaul communication unit 26. As shown in FIG. 4, a plurality of backhaul communication units 26 are provided in parallel in correspondence with identification information IDs that identify mobile communication carriers.

The identification information ID is unique information that identifies a mobile communication carrier, and for example , a public land mobile network (PLMN) number can be used. A PLMN number consists of a 3-digit country code and a 2-3 digit network number that identifies the operator. However, the identification information ID may be assigned using a system other than the PLMN number. Hereinafter, in order to simplify the explanation, the identification information of mobile communication carrier a will be expressed as IDa.

In FIG. 4, the backhaul communication unit 26a establishes a backhaul communication path BHa with the donor cell base station 30a associated with the identification information IDa that specifies the mobile communication carrier a, and communicates with the access communication unit 22. A connecting terminal device 10a is connected to a mobile communication network MNa. Further, the backhaul communication unit 26b establishes a backhaul communication path BHa with the donor cell base station 30b associated with the identification information IDb that specifies the mobile communication carrier b, and connects to the access communication unit 22. A terminal device 10b is connected to a mobile communication network MNb. Furthermore, the backhaul communication unit 26c establishes a backhaul communication path BHc with the donor cell base station 30c associated with the identification information IDc that specifies the mobile communication carrier c, and connects to the access communication unit 22. A terminal device 10c is connected to a mobile communication network MNc. In this way, it is possible to provide a backhaul communication unit 26x that can establish a specific backhaul communication path BHx for any mobile communication carrier x whose business is permitted.

Note that each of the backhaul communication units 26 is provided with means for restricting connection destinations. The connection destination restriction means has a function of permitting connection only to a specific mobile communication carrier and prohibiting connection to other mobile communication carriers. A typical example of such a restriction means is a SIM ( Subscriber Identity Module ). By providing a SIM in each backhaul communication unit 26, the donor cell base station 30 recognizes the backhaul communication unit 26 corresponding to each mobile communication carrier as a UE.

Identification information IDx for identifying a specific mobile communication carrier x is assigned to the SIM. The SIM can only be connected to the mobile communication network MNx operated by mobile communication carrier Connection to network MNy is restricted. In this embodiment, identification information IDa, IDb, and IDc are assigned to the SIMs provided in each of the backhaul communication units 26a, 26b, and 26c. Thereby, the backhaul communication units 26a, 26b, and 26c are exclusively connected to the mobile communication networks MNa, MNb, and MNc, respectively. The SIM may be configured to be removably attached to each backhaul communication unit 26 in the form of a SIM card that is hardware, or configured to set arbitrary identification information IDx as an eSIM (embedded SIM) that is software. may have been done.

SIM cards are provided in various formats such as standard SIM, micro SIM, and nano SIM. By replacing SIM cards to which different identification information IDs have been assigned, it is possible to change the connection destination to a different mobile communication network MN.

When the eSIM is applied, it is attached to the card reader of the backhaul communication unit 26, for example, as a rewritable memory card. It is configured such that the identification information ID can be downloaded to the memory card of the corresponding backhaul communication unit 26 from a remote location. For example, the identification information IDa is downloaded to the memory card of the backhaul communication unit 26a. By this operation, the backhaul communication unit 26a is set to exclusively connect to the mobile communication network MNa. According to eSIM, even if a specific identification information IDx is once downloaded to the memory card to connect exclusively to the mobile communication network MNx, other identification information IDy can later be downloaded and rewritten to connect to a different mobile communication network. It is possible to change it so that it connects exclusively to the communication network MNy.

Next, the basic functions of the division/integration section 24 will be explained with reference to FIG. 5. FIG. 5 is a schematic diagram illustrating the basic operation of the division and integration section 24. As shown in FIG. 5, the division/integration unit 24 is provided between the access communication unit 22 and the plurality of backhaul communication units 26.

The division/integration unit 24 supplies the uplink data provided from the access communication unit 22 to the backhaul communication unit 26x that has established the backhaul communication path BHx associated with the identification information IDx included in the uplink data. do. Specifically, the identification information determination unit 242 of the division and integration unit 24 refers to the identification information IDx included in the uplink data. Then, the block of packet data to which the identification information IDx is attached is supplied to the corresponding backhaul communication unit 26x. Through this operation, the integrated data CD is sorted into divided data SD for each mobile communication carrier.

Furthermore, the division and integration unit 24 sequentially supplies downlink data from one or more backhaul communication paths BH to the access communication unit 22. Specifically, the packet data received and transferred by the backhaul communication unit 26 is integrated block by block in the order of arrival to generate integrated data CD. Through this operation, blocks of packet data transmitted individually from each mobile communication carrier are integrated.

The cell formed by the relay device 20 configured as described above is limited to the bases existing in the vicinity due to reasons such as the narrow frequency band in the relay device 20, communication congestion between the terminal device 10 and the backhaul, and the occurrence of weak electricity. There is a possibility that the throughput will be lower than that of the station's cell.

In this case, the relay device 20 applies ( performs ) carrier aggregation ( CA ). Carrier aggregation is a technology that performs communication by bundling radio waves (carriers) in multiple frequency bands. In carrier aggregation, a cell that ensures the connection between the terminal device 10 and the core network 70 is also called a primary cell ( PCell ). Furthermore, in carrier aggregation, a cell that provides radio resources in addition to the primary cell is also called a secondary cell ( SCell ). The first frequency band used in the primary cell and the second frequency band used in the secondary cell may be the same or different frequency bands.

Dual connectivity ( DC ) technology is applied when carrier aggregation is performed between multiple base stations with backhaul delays. Dual connectivity, which bundles radio waves (carriers) between different base stations, is specified in 3GPP Release 12. Dual connectivity uses radio resources of two base stations called a master base station (MeNB: Master - eNB ) and a secondary base station (SeNB: Secondary - eNB ). Therefore, it may be difficult to reflect UCI ( Uplink Control Information ) and scheduling requests received by the primary cell of the master base station to the secondary base station via the backhaul in real time. Therefore, dual connectivity stipulates that the terminal device 10 transmits the UCI and scheduling request to one cell under the secondary base station in addition to the primary cell. This cell is also called a primary secondary cell (PSCell: Primary SCell ). Dual connectivity also allows simultaneous communication between cells under the same base station. Control of the secondary cell is performed by the primary cell when the secondary cell is under a master base station, and is performed by the primary secondary cell when the secondary cell is under the secondary base station. In the following, to simplify the explanation, it is assumed that the secondary cell is under the master base station unless otherwise specified.

Next, the general operation of carrier aggregation by the terminal device 10 and the relay device 20 will be described with reference to FIG. 6. FIG. 6 is a flowchart illustrating the general operation of carrier aggregation by the terminal device 10 and the relay device 20.

For example, when the terminal device 10 establishes an RRC connection in a radio resource control (RRC) layer via the relay device 20 and camps on a cell established by the access communication unit 22, the terminal device 10 and the relay The device 20 executes CA processing S300 shown in FIG.

Note that before executing the CA processing S300, or in parallel with or in parallel with the execution of the CA processing S300, the relay device 20 performs access communication with the terminal device 10 using the radio wave (carrier) of the first cell using the above-mentioned function. The communication section 22 performs communication. The first cell is a cell formed by the relay device 20.

First, the relay device 20 transmits cell identification information of the second cell to notify the terminal device 10 that has camped on the first cell formed by the relay device 20 (S301). The second cell is a cell different from the first cell described above. The cell identification information is information that associates a cell with a base station forming the cell, and is, for example, a cell ID. The number of cell identification information transmitted to the terminal device 10 is not limited to one, and may be plural.

Next, the relay device 20 determines whether the terminal device 10 has detected the second cell identified by the cell identification information notified in step S301 (S302). Relay device 20 receives a report indicating cell detection from terminal device 10 and makes a determination based on the received report. The report includes cell identification information of the cell detected by the terminal device 10. The relay device 20 repeats the determination in step S302 until the terminal device 10 detects the second cell identified by the cell identification information notified in step S301.

As a result of the determination in step S302, if the terminal device 10 detects the second cell identified by the cell identification information notified in step S301, the relay device 20 uses the radio waves (carrier) of the second cell to The terminal device 10 is instructed to communicate with the base station associated with the identification information of the two cells (S303). The relay device 20 sends and notifies the terminal device 10 of a communication instruction including the identification information of the second cell detected by the terminal device 10. This instructs communication using the second cell with the base station associated with the identification information of the second cell.

For example, in the configuration shown in FIG. 1, when the relay device 20 that communicates with the terminal device 10a using the radio wave (carrier) of the first cell executes the CA processing S300, the terminal device 10a Communication can be performed between the donor cell base station 30a or the macrocell base station 35a using the radio waves (carrier) of the second cell.

In this way, the terminal device 10 and the relay device 20 can realize carrier aggregation using two cells including the access communication unit 22, improving communication speed and realizing stable high-speed communication. I can do it.

Note that, to simplify the explanation, an example of carrier aggregation using radio waves (carrier waves) in two frequency bands is shown, but the present invention is not limited to this. For example, the relay device 20 may perform carrier aggregation using radio waves (carriers) of three or more cells.

The terminal device 10 and the relay device 20 need to hold the cell identification information of the second cell in advance in order to execute the CA processing S300 shown in FIG. In addition, when relaying communication between the donor cell base station 30 and the terminal device 10 using the radio waves (carrier) of the first cell, the relay device 20 relays the communication using the radio waves (carrier) of the second cell and the frame It is necessary to synchronize the timing.

Next, the software configuration of the control unit 200 will be described with reference to FIG. 7. FIG. 7 is a configuration diagram illustrating the software configuration of the control unit 200.

As shown in FIG. 7, the control unit 200 includes a management unit 211, a communication quality information acquisition unit 212, a determination unit 213, a notification unit 214, a synchronization information acquisition unit 215, and a timing control unit. 216.

With the above-mentioned components, the relay device 20 of this embodiment is configured to be able to implement the following relay method of relaying communication between the donor cell base station 30 and the terminal device 10 using the first cell.
(1) A step of managing the registration of cell identification information that associates a cell with a base station forming the cell, and a step of registering cell identification information of a second cell different from the first cell (management unit 211).
(2) A step of notifying the terminal device 10 of the cell identification information of the second cell (notifying unit 214).
(3) A step of acquiring synchronization information for synchronizing communication using the second cell between the base station associated with the cell identification information of the second cell and the terminal device 10 (synchronization information acquisition unit 215).
(4) A step of controlling frame timing when relaying communication from donor cell base station 30 to terminal device 10 based on synchronization information (timing control unit 216).

Hereinafter, the components that execute each step will be specifically explained.

The management unit 211 is configured to manage registration of cell identification information that associates cells with base stations forming the cells. Furthermore, the management unit 211 is configured to register cell identification information of the second cell. The cell identification information of the second cell to be registered is stored in the memory 202 or the storage unit 204, for example. The number of cell identification information of the second cell to be registered is not limited to one, but may be plural. When the second cell is a cell formed by the master base station, that is, the donor cell base station 30, the management unit 211 stores the cell identification information of the second cell as an SCell Index, and stores the second cell as the secondary base station. That is, if the cell is formed by a base station other than the donor cell base station 30, the management unit 211 stores the cell identification information of the second cell as a PSCell Index.

The cell identification information of the second cell registered by the management unit 211 is registered in units of PLMNs or groups, for example, for each PLMN number. Thereby, it is possible to register cell identification information of a different second cell for each mobile communication carrier. Furthermore, the management unit 211 may periodically review the cell identification information of the second cell to be registered. For example, the management unit 211 may control cells that have not been used for a predetermined period of time, cells that have fallen below a predetermined communication quality, cells formed by the donor cell base station 30, cells of specific cells listed in a blacklist, etc. The identification information may be deleted from the registered cell identification information of the second cell.

The second cell in which the management unit 211 registers cell identification information is selected from among the plurality of cells by applying at least one of the following first to fourth methods, for example.

(First method)
First, a first method of selecting a base station will be described with reference to FIGS. 8 and 9. FIG. 8 is a schematic diagram illustrating an example of the first method of selecting the second cell. FIG. 9 is a schematic diagram illustrating another example of the first method of selecting the second cell.

The first method is to select a second cell based on communication quality. The communication quality information acquisition unit 212 is configured to acquire communication quality information regarding the communication quality of the cell associated with the cell identification information. Specifically, as shown in FIG. 8, for example, the communication quality information acquisition unit 212 performs Network Listening to search for cells around the relay device 20, and acquires communication quality information for each cell. Furthermore, as shown in FIG. 9, for example, the communication quality information acquisition unit 212 receives an MR ( Measurement Report ) executed by a terminal device 10 residing in a cell formed by the relay device 20 from the terminal device 10. , acquires communication quality information of the cell where the terminal device 10 is located. Communication quality information includes, for example, RSRP ( Reference Signal Received Power ) , RSSI ( Received Signal Strength Indicator ), RSRQ ( Reference Signal Received Quality ), and SINR ( Signal to Interference ). plus Noise Ratio ), etc.

The determination unit 213 is configured to determine, based on the communication quality information, whether or not to register the cell identification information of the cell from which the communication quality information has been acquired. Specifically, the determination unit 213 compares the communication quality indicated by the communication quality information with a predetermined standard, and if the quality is equal to or higher than the predetermined quality, determines to register the cell identification information, and if the quality is less than the predetermined quality, determines to register the cell identification information. It is determined that the cell identification information is not registered. Then, the management unit 211 registers the cell identification information as the cell identification information of the second cell according to the determination result of the determination unit 213. Thereby, the relay device 20 can use a cell whose communication quality is equal to or higher than a predetermined quality as the second cell.

(Second method)
Next, a second method for selecting the second cell will be described with reference to FIG. 10. FIG. 10 is a schematic diagram illustrating a second method of selecting a second cell.

The second method is to select cell identification information of a cell stored in an NRT (Neighbor Relation Table). The NRT is stored, for example, in the memory 202 or the storage unit 204, and mainly stores information on handover destination candidates for the terminal device 10. The relay device 20 stores information on cells formed in the vicinity of the relay device 20 in the NRT, and the NRT includes cell identification information. Further, the relay device 20 periodically reviews and updates the cell identification information stored in the NRT.

The management unit 211 registers the cell identification information of the cell stored in the NRT as the cell identification information of the second cell. For example, as shown in FIG. 10, "Cell A" is stored in the NRT as the cell identification information of the cell formed by the macro cell base station 35A, and "Cell B" is stored as the cell identification information of the cell formed by the macro cell base station 35B. If so, the management unit 211 stores “Cell A” and “Cell B” in the SCell Index. Thereby, a cell formed near the relay device 20 can be used as the second cell.

(Third method)
Next, a third method for selecting the second cell will be described with reference to FIG. 11. FIG. 11 is a schematic diagram illustrating a third method of selecting the second cell.

The third method is to select a cell of a donor cell base station.

The management unit 211 registers the cell identification information of the cell formed by the donor cell base station as the cell identification information of the second cell. For example, as shown in FIG. 11, the management unit 211 stores cell identification information “DeNB Cell” of the donor cell base station 30 in the SCell Index. Thereby, the cell formed by the donor cell base station 30 can be used as the second cell.

(Fourth method)
Next, a fourth method for selecting the second cell will be described with reference to FIGS. 12 and 13. FIG. 12 is a schematic diagram illustrating an example of the fourth method of selecting the second cell. FIG. 13 is a schematic diagram illustrating another example of the fourth method of selecting the second cell.

The fourth method is to select a cell associated with cell identification information possessed by a donor cell base station.

Similarly to the relay device 20, the donor cell base station 30 performs network listening to search for surrounding cells, receives MR executed by the terminal device 10 located in the donor cell from the terminal device 10, etc. The cell identification information of the cell obtained by this is stored in the SCell Index or the PSCell Index. Furthermore, the donor cell base station 30 stores cell identification information of cells formed nearby in the NRT.

The management unit 211 of the relay device 20 registers the cell identification information received from the donor cell base station 30 as the cell identification information of the second cell. For example, as shown in FIG. 12, "Cell A" is the cell identification information of the cell formed by the macro cell base station 35A, "Cell B" is the cell identification information of the cell formed by the macro cell base station 35B, and the donor cell base station 30, the management unit 211 receives these cell identification information and stores "Cell A" and "Cell B" in the SCell Index, for example. Further, as shown in FIG. 13, "Cell A" is the cell identification information of the cell formed by the macro cell base station 35A, and "Cell B" is the cell identification information of the macro cell base station 35B, which is the cell identification information of the donor cell base station 30. If stored, the management unit 211 receives these cell identification information and stores "Cell A" and "Cell B" in, for example, SCell Index. Thereby, the cell associated with the cell identification information held by the donor cell base station 30 can be used as the second cell.

Returning to the explanation of FIG. 7, the notification unit 214 is configured to notify the terminal device 10 of the identification information of the second cell. The identification information of the second cell notified by the notification unit 214 is registered by the management unit 211. When there is a plurality of cell identification information of the second cells registered by the management unit 211, the notification unit 214 transmits each of the identification information of the plurality of second cells to the terminal device 10 to notify it. In this case, the notification unit 214 may transmit the identification information of the plurality of second cells at once, or may transmit the identification information several times. Further, the timing at which the notification unit 214 notifies the terminal device 10 of the identification information of the second cell is, for example, when the terminal device 10 camps on the first cell formed by the access control unit 22 of the relay device 20. The cell identification information of the second cell is transmitted to the terminal device 10 to notify it. In this way, by notifying the identification information of the second cell to the terminal device 10, the terminal device 10 can use the radio wave (carrier) of the second cell in addition to the radio wave (carrier) of the first cell by the relay device 20. This makes it possible to carry out carrier aggregation. Therefore, compared to the case where only the first cell is used, a decrease in throughput can be suppressed, and a throughput equivalent to that of cells formed by base stations existing in the vicinity can be maintained.

The notification unit 214 is configured to notify the terminal device 10 of an instruction to communicate with a base station associated with the identification information of the second cell using radio waves (carriers) of the second cell. Good too. The notification unit 214 notifies the instruction by transmitting an instruction, for example, when the terminal device 10 receives a report indicating that the second cell has been detected from the terminal device 10.

The synchronization information acquisition unit 215 is configured to acquire synchronization information. The synchronization information is information for synchronizing communication between the base station associated with the cell identification information of the second cell and the terminal device 10 using the second cell.

More specifically, the synchronization information acquisition unit 215 is configured to acquire propagation delay time information as the aforementioned synchronization information. The propagation delay time information is information indicating the propagation delay time in communication with a predetermined base station.

The timing control unit 216 is configured to control frame timing when relaying communication from the donor cell base station 30 to the terminal device 10 based on synchronization information. Thereby, it becomes possible to synchronize communication between the base station associated with the cell identification information of the second cell and the terminal device 10 using the second cell. Therefore, carrier aggregation can be performed by the relay device 20 in which the radio waves (carrier) of the first cell and the radio waves (carrier) of the second cell are synchronized.

More specifically, the timing control unit 216 is configured to advance the frame timing when relaying communication from the donor cell base station 30 to the terminal device 10 based on the propagation delay time information.

Specifically, the synchronization information acquisition unit 215 acquires propagation delay time information by performing NDT (Network Derived Timing) with a predetermined base station. That is, in NDT, the base station transmits a TA ( Timing Advance ) Command to the relay device 20. The TA Command includes information on the total delay time of downlink and uplink between the base station and the relay device 20, and the synchronization information acquisition unit 215 extracts this information from the received TA Command. to obtain propagation delay time information.

The timing control unit 216 calculates, for example, a value of 1/2 of the propagation delay time information acquired by the synchronization information acquisition unit 215. Then, the timing control unit 216 advances the frame timing by the calculated value in the downlink that relays communication from the donor cell base station 30 to the terminal device 10 using the radio wave (carrier) of the first cell. In this way, by advancing the frame timing when relaying communication from the donor cell base station 30 to the terminal device 10 based on the propagation delay time information, the delay time due to propagation can be reflected in the frame timing control. This makes it possible to easily synchronize communication using the second cell.

In the above description, an example was given in which the timing control unit 216 calculates a value of 1/2 of the propagation delay time information, but the present invention is not limited to this. For example, in a communication system where a base station that performs NDT has the same propagation delay time for downlink and uplink, such as time division duplex (TDD: Time Division Duplex ) - LTE, the propagation delay time The base station that calculates 1/2 the value of the information and performs NDT uses frequency division duplexing ( FDD ) - as in LTE, the downlink and uplink propagation delay times are different. In the communication method, the timing control unit 216 may advance the timing of the communication frame by the calculated value using another value or another method. For example, if a base station that attempts to perform NDT uses the FDD-LTE communication method, the relay device 20 searches for a base station that uses the TDD-LTE communication method and changes the base station that is the target of NDT. Alternatively, synchronization information other than propagation delay time information may be acquired using a method other than NDT. Further, the timing control unit 216 approximates the delay of the communication frame in the downlink by half the value of the propagation delay time information, or approximates it from time information based on the clocks of the base station and the relay device 20, A deviation may be allowed.

Next, a predetermined base station where the synchronization information acquisition unit 215 performs NDT will be described with reference to FIGS. 14 to 16. FIG. 14 is a schematic diagram illustrating an example of the operation of the synchronization information acquisition unit 215. FIG. 15 is a schematic diagram illustrating another example of the operation of the synchronization information acquisition unit 215. FIG. 16 is a schematic diagram illustrating still another example of the operation of the synchronization information acquisition unit 215.

As shown in FIG. 14, when the terminal device 10 communicates with the macro cell base station 35 using radio waves (carriers) of the second cell, the synchronization information acquisition unit 215 performs NDT communication with the donor cell base station 30, for example. may be performed to obtain propagation delay time information.

Further, as shown in FIG. 15, when the terminal device 10 communicates with the macro cell base station 35 using radio waves (carriers) of the second cell, the synchronization information acquisition unit 215 communicates with the macro cell base station 35, which is an SCell, for example. Propagation delay time information may be obtained by performing NDT between the two terminals.

Furthermore, as shown in FIG. 16, when the terminal device 10 communicates with the macro cell base station 35 using radio waves (carriers) of the second cell, the synchronization information acquisition unit 215 uses, for example, the macro cell base station that exists in the vicinity. 35B to obtain propagation delay time information.

In the above description, an example has been shown in which there is one predetermined base station that performs NDT, but the present invention is not limited to this. For example, the synchronization information acquisition unit 215 may perform NDT with multiple base stations. In this case, the synchronization information acquisition unit 215 may calculate an average value or a median value of the total delay times of a plurality of downlinks and uplinks extracted from each TA command. Furthermore, the base stations that perform NDT may be limited to base stations that have the same PLMN number as the PLMN that performs carrier aggregation, in units of PLMNs or groups. Furthermore, the base station that performs NDT may be a base station with good communication quality, such as a base station with RSRP of a predetermined value or higher, or a base station with a specific PLMN number or a base station forming a specific cell. You may.

[Second embodiment]
<Relay system>
Next, a relay system according to a second embodiment of the present invention will be described with reference to FIGS. 17 to 19. Note that the same or similar configurations as those in the first embodiment are given the same or similar symbols. Hereinafter, points different from the first embodiment will be explained. Further, similar effects due to similar configurations will not be mentioned sequentially.

First, the configuration of a relay system according to a second embodiment of the present invention will be described with reference to FIG. 17. FIG. 17 is a schematic diagram schematically showing the configuration of a relay system 400 in the second embodiment.

As shown in FIG. 17, relay system 400 includes a relay device 20A and a base station management device 410.

The base station management device 410 stores, for each of the plurality of base stations managed by the device, cell identification information that associates the cell formed by the base station with the base station, and location information indicating the location of the base station. configured to manage. The location information is, for example, latitude and longitude information. In the example shown in FIG. 17, base station management device 410 stores cell identification information and location information of donor cell base station 30, and cell identification information and location information of macro cell base station 35A.

Furthermore, when the base station management device 410 receives a request from the relay device 20A, the base station management device 410 responds to the request with cell identification information of cells formed by base stations within a predetermined distance from the location of the relay device 20. It is configured. In the example shown in FIG. 17, the relay device 20A is configured to acquire position information from a GPS ( Global Positioning System ) satellite GS. The location information is, for example, latitude and longitude information, as in the example described above. The request from the relay device 20A includes position information acquired from the GPS satellite GS. The base station management device 410 transmits cell identification information of each of the donor cell base station 30 and the macro cell base station 35A located within the radius RA from the location indicated by the location information to the relay device 20A.

Note that the base station management device 410 stores the identification information and location information of the relay device 20A in advance, and refers to the location information of the relay device 20A in response to a request from the relay device 20A, and determines the location indicated by the referenced location information. Cell identification information of each of the donor cell base station 30 and the macro cell base station 35A located within the radius RA from the position may be transmitted to the relay device 20A.

Next, the software configuration of the control unit of the relay device in the second embodiment will be described with reference to FIG. 18. FIG. 18 is a configuration diagram illustrating the software configuration of the control unit 200A.

As shown in FIG. 18, the control unit 200A of the second embodiment includes a management unit 211A, a synchronization information acquisition unit 215A, and a timing control unit 216A instead of the management unit 211, the synchronization information acquisition unit 215, and the timing control unit 216. The control unit 200 is different from the control unit 200 of the first embodiment in that the control unit 200 includes the following.

For example, the management unit 211A transmits a request including position information acquired from the GPS satellite GS to the base station management device 410. The management unit 211A then receives a response from the base station management device 410.

Furthermore, the management unit 211A is configured to register the cell identification information included in the response from the base station management device 410 as the cell identification information of the second cell. Thereby, a cell formed by base stations within a predetermined range from the position of the relay device 20 can be used as the second cell.

Next, the operation of the synchronization information acquisition unit 215A will be described with reference to FIG. 19. FIG. 19 is a schematic diagram illustrating the operation of the synchronization information acquisition unit 215A.

The synchronization information acquisition unit 215A is configured to acquire time information from a GPS transmitter as synchronization information. For example, as shown in FIG. 19, the synchronization information acquisition unit 215A receives and acquires time information from the GPS satellite GS. Furthermore, the macro cell base station 35A similarly receives time information from the GPS satellite GS. The macro cell base station 35A operates based on the time information. Although FIG. 19 shows an example of receiving time information from the GPS satellite GS, the present invention is not limited to this. For example, in order to obtain more accurate time, the synchronization information obtaining unit 215A may receive and obtain time information from a plurality of GPS satellites.

The timing control unit 216A is configured to advance the frame timing when relaying communication from the donor cell base station 30 to the terminal device 10 based on the time information. In this way, by advancing the frame timing when relaying communication from the donor cell base station 30 to the terminal device 10 based on the time information acquired from the GPS satellite GS, the macro cell base station 35A operates with the same time information. This makes it easy to synchronize frame timing.

[Third embodiment]
<Relay system>
Next, a relay system according to a third embodiment of the present invention will be described with reference to FIGS. 20 to 22. Note that the same or similar configurations as those in the first embodiment are given the same or similar symbols. Hereinafter, points different from the first embodiment will be explained. Further, similar effects due to similar configurations will not be mentioned sequentially.

First, the configuration of a relay system according to a third embodiment of the present invention will be described with reference to FIG. 20. FIG. 20 is a schematic diagram schematically showing the configuration of a relay system 500 in the second embodiment.

As shown in FIG. 20, relay system 500 includes a relay device 20B and a time management device 510.

The time management device 510 is configured to supply reference time information indicating a reference time to each of a plurality of base stations managed by the device. The time management device 510 includes, for example, a GMC (Grandmaster Clock) that supplies highly accurate time. In the example shown in FIG. 20, reference time information is supplied to each of the time management device 510, donor cell base station 30, and macro cell base station 35A. Furthermore, as will be described later, the time management device 510 also supplies reference time information to the relay device 20B.

Next, the software configuration of the control unit of the relay device in the third embodiment will be described with reference to FIG. 21. FIG. 21 is a configuration diagram illustrating the software configuration of the control unit 200B.

As shown in FIG. 21, the control unit 200B of the second embodiment differs from the first embodiment in that it includes a synchronization information acquisition unit 215B and a timing control unit 216B instead of the synchronization information acquisition unit 215 and timing control unit 216. It is different from the control section 200.

The synchronization information acquisition unit 215B is configured to acquire reference time information supplied by the time management device 510 as synchronization information.

Next, the operation of the timing control section 216B will be described with reference to FIG. 22. FIG. 22 is a schematic diagram illustrating the operation of the timing control section 216B.

The timing control unit 216B relays communication from the donor cell base station 30 to the terminal device 10 based on the deviation time from the reference time and the propagation delay time in communication with the time management device 510, which is calculated from the reference time information. It is configured to advance the timing of the frame. The time difference from the reference time and the propagation delay time in communication with the time management device 510 are calculated using, for example, NTP ( Network Time Protocol ), PTP ( Precision Time Protocol ), or the like. Specifically, when the time management device 510 is the master and the relay device 20B is the slave, if the master and the slave are asynchronous as shown in FIG. 22, the respective reference times T0 There is a gap between them. In the example shown in FIG. 22, the slave time Ts is ahead of the master time Tm by the amount of Offset. The slave receives a Sync message stamped with time Tm1 from the master at time Ts2, and compares time Ts2 and time Tm1. As a result, the value α (=Ts2−Tm1) shown in FIG. 22 is calculated. Next, the slave transmits a Sync message to the master at time Ts3, and the master records time Tm4 at which the Sync message is received. Then, the slave receives a Sync message including time Tm4 from the master, and compares time Tm4 and time Ts3. As a result, the value β (=Tm4-Ts3) shown in FIG. 22 is calculated.

Here, assuming that the downlink delay time DL Delay from the master to the slave is the same as the uplink delay time UL Delay from the slave to the master, the reference time of the relay device 20B and the time management device 510 The time difference Offset from the reference time is expressed as in the following equation (1) using a value α and a value β.
Offset=(α-β)/2…(1)

Similarly, the propagation delay time Delay in communication between the relay device 20B and the time management device 510 is expressed as the following equation (2) using the value α and the value β.
Delay=(α+β)/2…(2)

In this way, from the donor cell base station 30 to the terminal device 10 based on the offset time from the reference time of the time management device 510 and the propagation delay time Delay in communication with the time management device 510, which are calculated from the reference time information. By advancing the timing of the frame when relaying the communication, it is possible to easily synchronize the frame timing with the macro cell base station 35A based on the same reference time information.

Exemplary embodiments of the invention have been described above. According to the relay device 20 and relay method according to the first embodiment, the identification information of the second cell is notified to the terminal device 10. This allows the terminal device 10 to perform carrier aggregation using the second cell's radio wave (carrier) in addition to the first cell's radio wave (carrier) by the relay device 20. Therefore, compared to the case where only the first cell is used, a decrease in throughput can be suppressed, and a throughput equivalent to that of cells formed by base stations existing in the vicinity can be maintained. Further, based on the synchronization information, the timing of frames when relaying communication from the donor cell base station 30 to the terminal device 10 is controlled. Thereby, it becomes possible to synchronize communication between the base station associated with the cell identification information of the second cell and the terminal device 10 using the second cell. Therefore, carrier aggregation can be performed by the relay device 20 in which the radio waves (carrier) of the first cell and the radio waves (carrier) of the second cell are synchronized.

Furthermore, according to the relay system 400 according to the second embodiment, the cell identification information included in the response from the base station management device 410 is registered as the cell identification information of the second cell. Thereby, a cell formed by base stations within a predetermined range from the position of the relay device 20 can be used as the second cell.

Further, according to the relay system 500 according to the third embodiment, the time difference Offset from the reference time of the time management device 510 and the propagation delay time Delay in communication with the time management device 510 are calculated from the reference time information. , the frame timing when relaying communication from the donor cell base station 30 to the terminal device 10 is advanced. Thereby, it is possible to easily synchronize the frame timing with the macro cell base station 35A based on the same reference time information.

The embodiments described above are for facilitating understanding of the present invention, and are not intended to be interpreted as limiting the present invention. The present invention may be modified/improved without departing from its spirit, and the present invention also includes equivalents thereof. In other words, the scope of the present invention includes modifications to each embodiment by those skilled in the art as long as they have the characteristics of the present invention. For example, each element provided in the embodiment, its arrangement, material, conditions, shape, size, etc. are not limited to those illustrated and can be changed as appropriate. Further, the embodiments are merely illustrative, and it goes without saying that partial substitutions or combinations of the configurations shown in different embodiments are possible, and these are also included within the scope of the present invention as long as they include the characteristics of the present invention.

10, 10a, 10b, 10c... terminal device, 20, 20A, 20B... relay device, 22... access communication section, 24... division and integration section, 26, 26a, 26b, 26c, 26x... backhaul communication section, 30, 30a , 30b, 30c... Donor cell base station, 35, 35A, 35B, 35a, 35b... Macro cell base station, 40, 40a first core network, 50, 50a, 50b... Virtual base station device, 60, 60a... Second core network , 70... Core network, 80... External network, 100... Mobile communication system, 200, 200A, 200B... Control unit, 201... Processor, 202... Memory, 204... Storage unit, 206... Interface circuit, 210... Interface circuit, 211, 211A... Management unit, 212... Communication quality information acquisition unit, 213... Judgment unit, 214... Notification unit, 215, 215A, 215B... Synchronization information acquisition unit, 216, 216A, 216B... Timing control unit, 222... Antenna, 242...Identification information determination unit, 262...Antenna, 400...Relay system, 410...Base station management device, 500...Relay system, 510...Time management device, Delay...Propagation delay time, GS...GPS satellite, Offset...Shift time, RA...Radius, S300...CA processing.

Claims (9)

A relay device that relays communication between a donor cell base station and a terminal device using a first cell,
a management unit that manages registration of cell identification information that associates a cell with a base station forming the cell, the management unit that registers the cell identification information of a second cell different from the first cell;
a notification unit that notifies the terminal device of the cell identification information of the second cell;
a first acquisition unit that acquires synchronization information for synchronizing communication between a base station associated with the cell identification information of the second cell and the terminal device using the second cell;
a timing control unit that controls frame timing based on the synchronization information in a downlink that relays communication from the donor cell base station to the terminal device ;
The first acquisition unit acquires, as the synchronization information, a plurality of pieces of propagation delay time information each indicating a propagation delay time in communication with a predetermined base station,
The timing control unit advances frame timing when relaying communication from the donor cell base station to the terminal device based on the plurality of propagation delay time information.
Relay device. a second acquisition unit that acquires communication quality information regarding the communication quality of the cell associated with the cell identification information;
further comprising a determination unit that determines whether or not to register the cell identification information based on the communication quality information,
The management unit registers the cell identification information as the cell identification information of the second cell according to the result of the determination.
The relay device according to claim 1. The management unit registers the cell identification information of a cell formed in the vicinity of the relay device as the cell identification information of the second cell.
The relay device according to claim 1 or 2. The management unit registers the cell identification information of a cell formed by the donor cell base station as the cell identification information of the second cell.
The relay device according to any one of claims 1 to 3. The management unit registers the cell identification information received from the donor cell base station as the cell identification information of the second cell.
The relay device according to any one of claims 1 to 4. The first acquisition unit acquires time information from a GPS transmitter as the synchronization information,
The timing control unit advances the timing of a frame when relaying communication from the donor cell base station to the terminal device based on the time information.
The relay device according to any one of claims 1 to 5. A relay method for relaying communication between a donor cell base station and a terminal device using a first cell, the relay method comprising:
a step of managing registration of cell identification information that associates a cell with a base station forming the cell, the step of registering the cell identification information of a second cell different from the first cell;
Notifying the cell identification information of the second cell to the terminal device;
acquiring synchronization information for synchronizing communication between a base station associated with the cell identification information of the second cell and the terminal device using the second cell;
In a downlink that relays communication from the donor cell base station to the terminal device , controlling frame timing based on the synchronization information,
The step of acquiring the synchronization information includes acquiring, as the synchronization information, a plurality of pieces of propagation delay time information each indicating a propagation delay time in communication with a predetermined base station,
The step of controlling the timing includes advancing the timing of a frame when relaying communication from the donor cell base station to the terminal device based on the plurality of propagation delay time information.
Relay method. a relay device that relays communication between the donor cell base station and the terminal device using the first cell;
A base station management device that manages, for each of a plurality of base stations, cell identification information that associates a cell formed by the base station with the base station, and location information that indicates the location of the base station, the relay device a base station management device that responds to a request from the relay device with the cell identification information of a cell formed by a base station within a predetermined distance from the location of the relay device;
The relay device is
a management unit that manages registration of the cell identification information, the management unit that registers the cell identification information of a second cell different from the first cell;
a notification unit that notifies the terminal device of the cell identification information of the second cell;
an acquisition unit that acquires synchronization information for synchronizing communication between a base station associated with the cell identification information of the second cell and the terminal device using the second cell;
a timing control unit that controls frame timing when relaying communication from the donor cell base station to the terminal device based on the synchronization information;
The management unit registers the cell identification information included in the response from the base station management device as the cell identification information of the second cell,
The acquisition unit acquires, as the synchronization information, a plurality of pieces of propagation delay time information each indicating a propagation delay time in communication with a predetermined base station,
The timing control unit advances frame timing when relaying communication from the donor cell base station to the terminal device based on the plurality of propagation delay time information.
Relay system. a relay device that relays communication between the donor cell base station and the terminal device using the first cell;
a time management device that provides reference time information indicating a reference time to each of the plurality of base stations;
The relay device is
a management unit that manages cell identification information that associates a cell with a base station forming the cell, the management unit that registers the cell identification information of a second cell different from the first cell;
a notification unit that notifies the terminal device of the cell identification information of the second cell;
an acquisition unit that acquires synchronization information for synchronizing communication between a base station associated with the cell identification information of the second cell and the terminal device using the second cell;
a timing control unit that controls frame timing when relaying communication from the donor cell base station to the terminal device based on the synchronization information;
The acquisition unit acquires the reference time information as the synchronization information,
The timing control unit controls communication from the donor cell base station to the terminal device based on a time difference from the reference time and a propagation delay time in communication with the time management device, which is calculated from the reference time information. Advance frame timing when relaying,
The acquisition unit acquires, as the synchronization information, a plurality of pieces of propagation delay time information each indicating a propagation delay time in communication with a predetermined base station,
The timing control unit advances frame timing when relaying communication from the donor cell base station to the terminal device based on the plurality of propagation delay time information.
Relay system.

Images