JP7385485B2 - Wireless communication unit and wireless network system using it - Google Patents

Description

The present invention relates to a wireless communication unit for performing wireless network communication with a mobile terminal, and can easily realize cooperative operation between multiple units and can be suitably used for wide area coverage. The present invention relates to a wireless communication unit and a wireless network system using the same.

For example, in wireless communication networks based on high-speed communication standards based on 3GPP specifications (for example, LTE (Long Term Evolution)) or WiMAX (Worldwide Interoperability for Microwave Access), the EPC (Evolved Packet Core) that accommodates the wireless communication access network is The wireless base station to which the mobile terminal connects receives control of transmission and reception of IP packets via the EPC. On the other hand, with the spread of mobile terminals such as mobile phones, smartphones, and tablet PCs, areas where EPC and wireless base stations are not well-developed, such as offshore areas, depopulated areas, or areas where communication functions have been lost due to disasters, etc. There is also an increasing desire to use mobile terminals in areas (hereinafter referred to as "wireless undeveloped areas").

In order to meet these demands, for example, Patent Document 1 proposes a composite wireless communication unit that integrates a wireless base station and an EPC function unit. By installing such a wireless communication unit in an area with no wireless infrastructure, the wireless base station included in the unit will establish a small communication area, and the EPC function within the unit will control communication. By doing so, it becomes possible to perform wireless communication between a plurality of mobile terminals connected to the wireless base station section. However, the cell that can be covered by one wireless communication unit is small, and the communication capacity is also limited. In this case, it is possible to arrange multiple wireless communication units in an area without wireless infrastructure, but communication coordination between units is not taken into account, and mobile terminals connected to different complex devices cannot communicate with each other. , there is a drawback. Furthermore, when the number of connected mobile terminals increases or large amounts of data such as video data are transmitted and received, and communication traffic within an area becomes excessive, problems such as congestion tend to occur.

Therefore, Patent Documents 2 to 7 disclose configurations in which a plurality of wireless communication units are linked and communication traffic from a mobile terminal is distributed and transferred to each wireless communication unit. Specifically, FIG. 6 of Patent Document 5 discloses a mode in which a satellite device is used as a cooperation route between wireless communication units to offload communication with a mobile terminal.

Unexamined Japanese Patent Publication No. 2016-12841 Japanese Patent Application Publication No. 2018-137661 Japanese Patent Application Publication No. 2018-137662 Japanese Patent Application Publication No. 2018-137663 Japanese Patent Application Publication No. 2018-137664 Japanese Patent Application Publication No. 2018-137665 Japanese Patent Application Publication No. 2018-137666

Patent Documents 2 to 7 illustrate how a plurality of wireless communication units are interconnected (for example, FIG. 1 of Patent Document 2). Except for the offload mode via the satellite device mentioned above, there is no specific disclosure in the literature as to what entity constitutes this connection. However, if we assume that wireless communication units are connected by wire, if we try to distribute the wireless communication units in a fairly wide cell in an area with no wireless infrastructure, the communication cables that connect the devices will be very large. becomes longer. As a result, there is a problem in that signal quality and communication capacity deteriorate, and a relay device is required to prevent this, resulting in an increase in the cost of constructing a connection infrastructure. Furthermore, in applications where wireless communication units are mounted on moving objects such as trains, automobiles, and ships, it is physically impossible to connect each wireless communication unit with a cable.

Further, even if it is assumed that wireless communication units are also wirelessly connected, no specific study has been made on the form of interconnection between these wireless communication units. In particular, there are no countermeasures against congestion when the number of mobile terminals connecting to some wireless communication units increases and the communication traffic with a specific wireless communication unit becomes congested. The current situation is that no technical proposals have been made.

An object of the present invention is to make it possible to wirelessly link a plurality of wireless communication units with a simple structure, thereby easily realizing cooperative operation between the plurality of units, and to reduce communication traffic between specific wireless communication units. An object of the present invention is to provide a wireless communication unit that can make problems such as congestion less likely to occur even when the network is crowded, and a wireless network system using the same.

In order to solve the above problems, a wireless communication unit of the present invention is a wireless communication unit configured to be mounted on a mobile body and for performing wireless network communication with a mobile terminal, the wireless communication unit being configured to be able to be mounted on a mobile body. A wireless base station unit that can be connected via a terminal radio bearer, an EPC (Evolved Packet Core) function unit that is connected by wire to the wireless base station unit and functions as an upper network control unit for the wireless base station unit, and a wired connection to the EPC function unit. and a relay radio communication unit connectable to the radio base station unit of the first external radio communication unit via the first inter-unit radio bearer, the radio base station unit being connected to the radio base station unit of the first external radio communication unit. The EPC function unit connects to the wireless communication unit via the second inter-unit radio bearer, and the EPC function unit connects the same external wireless communication unit that is shared by the first external wireless communication unit and the second external wireless communication unit. As a backhaul construction target wireless communication unit, for at least one of a relay wireless communication unit and a wireless base station unit, for the relay wireless communication unit, a first unit is connected to the wireless base station unit of the backhaul construction target wireless communication unit. In order to construct a second inter-unit radio bearer between the radio base station unit and the relay radio communication unit of the backhaul construction target radio communication unit, A wireless backhaul construction control command section is provided in the wireless backhaul construction control section that issues a control command to construct a wireless backhaul consisting of the first inter-unit radio bearer and the second inter-unit radio bearer.

Further, the wireless network system of the present invention is a wireless communication unit configured to be mounted on a mobile body and for performing wireless network communication with a mobile terminal, wherein the mobile terminal communicates with the mobile terminal via a terminal radio bearer. a connectable wireless base station section, an EPC (Evolved Packet Core) functional section that is wired connected to the wireless base station section and functions as an upper network control section for the wireless base station section; a relay radio communication section connectable to the radio base station section of the external radio communication unit via the first inter-unit radio bearer; Connection is possible via an inter-unit radio bearer, and the EPC function unit connects the same external radio communication unit shared by the first external radio communication unit and the second external radio communication unit to the backhaul construction target radio communication unit. For at least one of the relay radio communication unit and the radio base station unit, the relay radio communication unit transmits a first inter-unit radio bearer between the radio base station unit of the radio communication unit to which the backhaul is to be constructed; For the local area, in order to construct a second inter-unit radio bearer between the relay radio communication unit of the backhaul construction destination wireless communication unit, the first inter-unit radio between the backhaul construction destination wireless communication unit and the a pair of wireless communication units provided with a wireless backhaul construction control command section that issues a control command for constructing a wireless backhaul consisting of a bearer and a second inter-unit radio bearer; the relay radio of one of the pair of wireless communication units; The communication unit and the other radio base station unit are connected by a first inter-unit radio bearer, and one radio base station unit and the other relay radio communication unit of the pair of radio communication units are connected by a second inter-unit radio bearer. Accordingly, a wireless backhaul is constructed between the paired wireless communication units.

In the above wireless communication unit (and wireless network system) of the present invention, the wireless backhaul construction control command unit is configured to control the wireless communication unit when the wireless base station unit is connected to the relay wireless communication unit of the second external wireless communication unit by the second inter-unit radio bearer. In this state, the relay wireless communication unit issues a wireless backhaul construction control command to the relay wireless communication unit, and upon receiving the wireless backhaul construction control command, the relay wireless communication unit issues a command to the wireless base station unit of the first external wireless communication unit. It can be configured to establish a first inter-unit radio bearer by requesting an attach. The wireless backhaul construction control command unit also controls the wireless backhaul construction for the wireless base station unit while the relay wireless communication unit is connected to the wireless base station unit of the first external wireless communication unit by the first inter-unit radio bearer. Upon receiving the control command for wireless backhaul construction, the wireless base station section sends a backhaul construction request to the relay wireless communication section of the second external wireless communication unit, and also sends the request to the relay wireless communication section of the second external wireless communication unit. The second inter-unit radio bearer can be constructed by receiving an attach request as a response to the backhaul construction request from the relay radio communication section.

Further, in the wireless communication unit (and wireless network system) of the present invention, a router can be provided to relay transmission and reception of IP packets between the EPC function section and the external network. The wireless backhaul construction control command unit issues a control command for wireless backhaul construction to at least one of the relay wireless communication unit and the wireless base station unit, with the necessary condition that a public network is connected to the router as an external network. It can be done. In this case, the EPC function section is configured to include a terminal connection number acquisition section that acquires information on the number of mobile terminals connected to the wireless base station section of the first external wireless communication unit or the wireless base station section of the second external wireless communication unit. The wireless backhaul construction control command unit issues a wireless backhaul construction control command to at least one of the relay wireless communication unit and the wireless base station unit, with the necessary condition that the number of connections exceeds a predetermined threshold. can be taken as a thing.

In the wireless communication unit and wireless communication network system of the present invention, a relay wireless communication unit connectable to an upstream unit (upstream wireless base station unit) that is another wireless communication unit on the upstream side via a first inter-unit radio bearer is provided. provided. Further, the radio base station section can be connected to a downstream unit (second external relay radio communication section), which is another radio communication unit on the downstream side, via a second inter-unit radio bearer. As a result, it becomes possible to connect a plurality of wireless communication units using an inter-unit radio bearer, and it is possible to easily construct a wireless network system that covers a wider area using a plurality of wireless communication units. The EPC function section has a first unit between its own relay wireless communication section and the wireless base station section of the backhaul construction destination wireless communication unit, with one of the external wireless communication units as a backhaul construction destination wireless communication unit. By constructing a second inter-unit radio bearer between its own radio base station section and the relay radio communication section of the backhaul construction target radio communication unit, the communication between two radio communication units including itself is achieved. A wireless backhaul construction control command unit is provided to construct a wireless backhaul by making the number of inter-unit radio bearers redundant to interconnect. As a result, in the wireless communication network system that is constructed, the relay wireless communication unit of one of the pair of wireless communication units and the wireless base station unit of the other are connected by the first inter-unit radio bearer, and the relay wireless communication unit of one of the pair of wireless communication units and the wireless base station unit of the other By connecting the wireless base station section of the wireless base station section and the relay wireless communication section of the other side by the second inter-unit radio bearer, a wireless backhaul is constructed between the pair of wireless communication units, and the wireless backhaul between the pair of wireless communication units is Even when communication traffic between the two terminals becomes congested, problems such as congestion can be made less likely to occur.

FIG. 1 is a schematic diagram showing the concept of a pair of wireless communication units that are constituent units of the wireless network system of the present invention. FIG. 2 is a block diagram schematically showing the electrical configuration of a pair of wireless communication units in FIG. 1. FIG. FIG. 2 is a block diagram showing an example of the electrical configuration of a wireless communication unit of the present invention. FIG. 1 is a block diagram showing an example of an electrical configuration of a UE (mobile terminal). A conceptual diagram of an IP packet. FIG. 2 is a diagram conceptually showing a 3GPP control plane protocol stack. FIG. 2 is a diagram conceptually showing a 3GPP user plane protocol stack. FIG. 3 is a diagram conceptually showing 3GPP downlink channel mapping. FIG. 4 is a diagram conceptually showing uplink channel mapping. FIG. 3 is a conceptual diagram showing the relationship between frequency band channels and resource blocks. 4 is a diagram schematically showing an example of a wireless network system constructed by cascading a plurality of wireless communication units of FIG. 3 using inter-unit radio bearers. FIG. FIG. 3 is a communication flow diagram showing an attach sequence of a relay wireless communication unit of a wireless communication unit to another upstream wireless communication unit. FIG. 2 is a communication flow diagram showing an attach sequence of a UE (mobile terminal) to a wireless communication unit. FIG. 3 is a communication flow diagram illustrating an example of a wireless backhaul construction procedure when a first inter-unit radio bearer is previously established with a backhaul construction destination wireless communication unit. FIG. 15 is an explanatory diagram of a wireless backhaul construction procedure according to the flow of FIG. 14; Explanatory diagram following FIG. 15. FIG. 3 is a communication flow diagram illustrating an example of a wireless backhaul construction procedure when a second inter-unit radio bearer is previously established with the backhaul construction destination wireless communication unit. FIG. 18 is an explanatory diagram of a wireless backhaul construction procedure according to the flow of FIG. 17; Explanatory diagram following FIG. 18. FIG. 3 is an explanatory diagram of a processing procedure for constructing a wireless backhaul when the number of mobile terminals connected to a backhaul construction destination wireless communication unit exceeds a threshold value. The block diagram which shows the modification of the wireless communication unit pair when multiple wireless base station parts are provided in one wireless communication unit. 22 is a conceptual diagram showing how a wireless backhaul is constructed in the wireless communication network system using the wireless communication unit pair of FIG. 21. FIG.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described based on the accompanying drawings.
FIG. 1 is a schematic diagram showing, as an embodiment, the concept of a pair of wireless communication units that are constituent units of a wireless network system of the present invention. The wireless communication unit pair includes wireless communication units 1 (A) and 1 (B) having the same configuration, which is an embodiment of the present invention (hereinafter also referred to as wireless communication unit pair 1 (A), 1 (B)). , each performs wireless communication with the UE (mobile terminal) 5 according to a communication protocol stack of a method specified by 3GPP (in this embodiment, LTE is used, but other methods such as WiMAX may be used). It is constructed as a thing.

The wireless communication units 1(A) and 1(B) are installed in large ships WS(A) and WS(B), which are moving bodies, respectively, and are wirelessly connected by an inter-unit radio bearer 55, which will be described in detail later. Each radio communication unit 1(A), 1(B) forms a cell 50(A), 50(B) to which a UE (mobile terminal) 5 can connect, respectively. In addition, small vessels FB (for example, fishing boats, tugboats, etc.) are operating around large vessels WS (A) and WS (B) (for example, fishing mother ships, tankers, etc.), and cell 50 (A) or cell 50 The crew of the small boat FB in (B) is carrying UE5. These UEs 5 are wirelessly connected to the nearest wireless communication units 1 (A) and 1 (B) by a terminal radio bearer 57, respectively. Note that the UE 5 may be carried by the crew members of the large ships WS (A) and WS (B). Further, the wireless communication units 1(A) and 1(B) may be installed in a moving body (such as a vehicle) other than a ship, or may be fixedly installed at a desired installation location on land, for example.

FIG. 2 shows a functional block configuration of wireless communication units 1(A) and 1(B). Wireless communication units 1(A) and 1(B) have the same electrical configuration. In this specification, when a plurality of wireless communication units and their components are shown to be distinguished from each other, the same number is given to the corresponding components, and a capital letter in parentheses is given following the number. Shown. On the other hand, when indicating each component without distinguishing between wireless communication units, the capital letters in parentheses may be omitted. Hereinafter, the description will mainly be made using the symbols on the side of the wireless communication unit 1 (A), but the description on the side of the wireless communication unit 1 (B) will also be made using the corresponding symbols as necessary.

The radio communication unit 1 (A) includes a radio base station section 4 (A) (eNodeB (evolved NodeB)) to which a UE (mobile terminal) 5 can connect via a terminal radio bearer 57, and a radio base station section 4 (A). The EPC (Evolved Packet Core) function section 3 (A) is connected by wire to the wireless base station section 4 (A) and functions as an upper network control section for the wireless base station section 4 (A). The EPC function section 3 (A) also has an upstream inter-unit radio bearer 55 (P) for the radio base station section 4 (B) (upstream radio base station section) of the upstream radio communication unit 1 (B). A relay wireless communication unit 9(A) connectable via a (upstream unit-to-unit wireless bearer) is connected by wire.

On the other hand, the wireless communication unit 1 (B) is connected by wire to a similar wireless base station section 4 (B) and the wireless base station section 4 (B), and functions as an upper network control section for the wireless base station section 4 (B). It includes an EPC function section 3 (B) and a relay wireless communication section 9 (B) connected by wire to the EPC function section 3 (B). If another radio communication unit is arranged upstream of the radio communication unit 1 (B), the relay radio communication unit 9 (B) transmits an inter-unit radio bearer to the radio base station of that radio communication unit. (See FIG. 11). In addition, the wireless base station section 4 (B) transmits the downstream inter-unit wireless communication to the relay wireless communication section 9 (A) (downstream relay wireless communication section) of the downstream wireless communication unit 1 (A) (downstream unit). Connection is possible via a bearer 55 (downstream inter-unit radio bearer). That is, the inter-unit radio bearer 55 becomes an upstream inter-unit radio bearer when viewed from the radio communication unit 1 (A), and becomes a downstream inter-unit radio bearer when seen from the radio communication unit 1 (B).

Next, in both wireless communication units 1(A) and 1(B) (hereinafter collectively referred to as wireless communication unit 1), the EPC function unit 3 is connected to an MME (Mobility Management Entity) 2, an S-GW (Serving Gateway) 6 serving as a gateway on the user plane side, an EPC function unit 3, and upstream network elements of the EPC function unit 3 (here, a router 8 (described later) and a relay wireless communication unit 9), and has a P-GW (PDN (Packet Data Network) Gateway) 7 that manages IP addresses for the upstream network element side (that is, the upstream unit side). Further, a plurality of UEs 5 are wirelessly connected to the radio base station section 4 via a terminal radio bearer 57.

On the control plane side, the radio base station unit (eNodeB) 4 is connected to the MME 2 via the S1-MME interface. Furthermore, on the user plane side, the wireless base station section 4 is connected to the S-GW 6 via the S1-U interface. Further, the S-GW 6 is connected to the P-GW 7 via the S5 interface.

FIG. 3 is a block diagram showing the electrical configuration of the wireless communication unit 1. The EPC function unit 3 is mainly composed of microcomputer hardware, including a CPU 301, a RAM 302 serving as a program execution area, and a mask ROM 303 (stores firmware for microcomputer hardware peripheral control that does not require permanent rewriting); (the same applies hereinafter) and a bus 306 that interconnects them. Further, a flash memory 305 is connected to the bus 306, and communication firmware 305a including an LTE protocol stack for EPC is stored therein, and each of the MME2, S-GW6, and P-GW7 in FIG. 2 uses the LTE protocol stack as a platform. Programs for an MME entity 305b, an S-GW entity 305c, and a P-GW entity 305d, which virtually implement functions, are installed. Furthermore, the flash memory 305 also stores a wireless backhaul construction control command program 305r for realizing the functions of the wireless backhaul construction control command section.

Further, an upstream communication interface 304A and a downstream communication interface 304B are connected to the bus 306. An input/output port for IP packets for P-GW is secured in the upstream communication interface 304A, and an input/output port for IP packets for S-GW is secured in the downstream communication interface 304B. In the above configuration, the MME 2, S-GW 6, and P-GW 7 in FIG. 2 are configured as virtual functional blocks on computer hardware, but each may be configured using independent hardware logic.

The wireless base station unit 4 is mainly composed of microcomputer hardware, and includes a CPU 401, a RAM 402 serving as a program execution area, a mask ROM 403, a bus 406 that interconnects them, and the like. A flash memory 405 is connected to the bus 406, and communication firmware 405a including an LTE protocol stack for wireless base stations is stored therein. Further, a wireless communication unit 412 and a communication interface 404 are connected to the bus 406 for wirelessly connecting to the UE by constructing a terminal radio bearer. The communication interface 404 is connected to the downstream communication interface 304B of the EPC function section 3 via the wired communication bus 31.

Furthermore, the relay wireless communication section is also mainly composed of microcomputer hardware and has the same electrical configuration. Therefore, one of them will be described as a representative (hereinafter, both relay wireless communication units will also be collectively referred to as relay wireless communication unit 9). The relay wireless communication unit 9 includes a CPU 901, a RAM 902 serving as a program execution area, a mask ROM 903, a bus 906 that interconnects them, and the like. A flash memory 905 is connected to the bus 906, and communication firmware 905a including an LTE protocol stack for the relay wireless communication unit is stored therein. Further, a wireless communication section 912 and a communication interface 904 are connected to the bus 906 for wirelessly connecting to an upstream wireless base station section by constructing an inter-unit radio bearer. The communication interface 904 is connected to the upstream communication interface 304A of the EPC function unit 3 by the wired communication bus 30. In the relay wireless communication unit 9, the LTE protocol stack for the relay wireless communication unit incorporated in the communication firmware 905a is , the same protocol stack as that for UE (mobile terminal), which will be described later, is used. In other words, the procedure for connecting the relay radio communication unit 9 to the upstream radio base station is the same as the attach sequence, which is the procedure for connecting a UE (mobile terminal).

Further, a router 8 that relays transmission and reception of IP packets between the EPC function unit 3 and the external network 60 is connected to the communication bus 30 (that is, a router 8 is connected between the EPC function unit 3 and the relay wireless communication unit 9). (A router 8 is installed in the router.) The external network 60 is, for example, a public network, specifically the Internet.

Next, the wireless communication unit 1 includes a removable secondary battery module 21 (for example, a lithium ion secondary battery module, a nickel metal hydride secondary battery module, etc.), a wireless base station section 4, an EPC function section 3, a router 8, and a Each functional circuit block of the relay wireless communication unit 9 and a power supply circuit unit 22 that converts the input voltage from the secondary battery module 21 into a driving voltage of each functional circuit block and outputs the drive voltage are integrated in a portable housing 23. It has an assembled structure. As a result, the wireless communication unit 1 can autonomously procure the driving power supply voltage from the secondary battery module 21, and can be used without problems even in installation locations where external power supply voltage such as commercial AC cannot be used (for example, at sea). be. The portable case 23 has a box shape made of metal or reinforced resin, and in the example shown in FIG. 3, casters 24C are provided at the bottom of the portable case 23, and casters 24C are placed on the back side for convenience of transportation or movement. A handle 24 is provided for use.

If the output voltage of the secondary battery module 21 drops due to discharge, remove the secondary battery module 21 from the portable housing 23 and attach it to a dedicated charger connected to a commercial AC power source or private power generator (not shown), for example. It is possible to charge the battery. Further, the power supply circuit section 22 can also receive power from an external power supply voltage such as the above-mentioned commercial alternating current or a centralized power supply section provided in a moving body, and can convert and output the above-mentioned driving power supply voltage. Furthermore, it is also possible to configure the secondary battery module 21 to be charged using the external power supply voltage. For example, if the power supply circuit section 22 is receiving power from a commercial alternating current or the like and the power reception is interrupted due to a power outage, the operation of the wireless communication unit 1 can be continued by switching to receiving power from the secondary battery module 21. It can also be configured as follows.

Next, FIG. 4 is a block diagram showing an example of the electrical configuration of the UE (mobile terminal) 5. As shown in FIG. UE5 is configured as a smartphone including microcomputer 100 as a processing entity. The microcomputer 100 includes a CPU 101, a RAM 102 serving as a program execution area, a ROM 103, an input/output section 104, a bus 106 interconnecting them, and the like. Further, a flash memory 105 is connected to the bus 106, and an OS (not shown) for constructing the operating environment of the UE 5, a terminal application 105b, etc. are installed therein.

Further, a monitor 109 is connected to the input/output unit 104 via a graphic controller 1091. A touch panel 110 serving as an input unit is superimposed on the monitor 109, and works with various software operation units (buttons, icons, etc.: see FIGS. 13 to 17) displayed on the monitor 109 to control the operation of the UE 5. Various necessary information inputs are made. Touch panel 110 is connected to input/output section 104 via touch panel controller 1101. A camera 111 for taking still images or moving images is connected to the input/output unit 104. Furthermore, a wireless communication section 112 is connected to the bus 106. The UE 5 is wirelessly connected to the radio base station section 4 of the radio communication unit 1 in FIG. 2 via the terminal radio bearer 57 at the radio communication section 112.

FIG. 5 is a schematic diagram showing the structure of an IP packet used for data transmission between the UE 5 and the wireless communication unit 1. The IP packet 1300 consists of an IP header 1301 and a payload 1302, and a PDU identification number, a data source address 1301a, a destination address 1301b, and the like are written in the IP header 1301.

6 and 7 show wireless protocol stacks in the LTE system, FIG. 6 shows a user plane protocol stack, and FIG. 7 shows a control plane protocol stack. The wireless protocol stack is divided into layers 1 to 3 of the OSI reference model, with layer 1 being the PHY (physical) layer. Layer 2 includes a MAC (Medium Access Control) layer, an RLC (Radio Link Control) layer, and a PDCP (Packet Data Convergence Protocol) layer. Layer 3 includes an RRC (Radio Resource Control) layer and a NAS (Non-Access Stratum) layer.

The role of each layer is as follows.
- PHY layer: performs encoding/decoding, modulation/demodulation, antenna mapping/demapping, and resource mapping/demapping. Data and control signals are transmitted between the PHY layer of the UE 5 and the relay radio communication unit 9 and the PHY layer of the radio base station unit (eNodeB) 4 via a physical channel.
- MAC layer: Performs data priority control, HARQ retransmission control processing, random access procedures, etc. Data and control signals are transmitted between the MAC layer of the UE 5 and the relay radio communication unit 9 and the MAC layer of the radio base station unit 4 via a transport channel. The MAC layer of the radio base station unit 4 includes a scheduler that determines uplink and downlink transport formats (transport block size, modulation and coding scheme (MCS)) and resource blocks to be allocated to the UE 5.

- RLC layer: transmits data to the RLC layer on the receiving side using the functions of the MAC layer and PHY layer. Data and control signals are transmitted between the RLC layer of the UE 5 and the RLC layer of the radio base station section 4 via logical channels.
- PDCP layer: Performs header compression/decompression, encryption/decryption of PDU.
- RRC layer: Defined only in the control plane that handles control signals. Messages for various settings (RRC messages) are transmitted between the RRC layer of the UE 5 and the RRC layer of the radio base station section 4. The RRC layer controls logical, transport and physical channels according to the establishment, re-establishment and release of radio bearers. If there is a connection (RRC connection) between the RRC of the UE5 and the RRC of the radio base station unit 4, the UE5 is in RRC connected mode, otherwise it is in RRC idle mode.

The above layers are used in both the control plane and the user plane. On the other hand, only the control plane, the UE 5, the relay wireless communication unit 9, and the MME 2 are provided with a NAS layer that performs session management, mobility management, etc. higher than the RRC layer. Further, a user data transmission interface between the radio base station section 4 and the EPC function section 3 side is provided with a GTP-U (GPRS (General Packet Radio Service) Tunneling Protocol for User Plane) layer. The GTP-U layer is for identifying the connection destination UE 5 or relay radio communication unit 9 and identifying the radio bearer to be used.

Next, FIG. 8 shows downlink channel mapping in the LTE system. Here, a mapping relationship between a logical channel (Downlink Logical Channel), a transport channel (Downlink Transport Channel), and a physical channel (Downlink Physical Channel) is shown. Below, they will be explained in order.
- DTCH (Dedicated Traffic Channel) is a dedicated logical channel for data transmission. DTCH is mapped to DLSCH (Downlink Shared Channel), which is a transport channel.

- DCCH (Dedicated Control Channel): A logical channel for transmitting dedicated control information between the UE 5 and the network. DCCH is used when the UE 5 and the relay radio communication unit 9 have an RRC connection with the radio base station unit 4. DCCH is mapped to DLSCH.
- CCCH (Common Control Channel): A logical channel for transmitting control information between the UE 5, the relay radio communication section 9, and the radio base station section 4. CCCH is used when the UE 5 and the relay radio communication unit 9 do not have an RRC connection with the radio base station unit 4. CCCH is mapped to DLSCH.

- BCCH (Broadcast Control Channel): A logical channel for distributing system information. The BCCH is mapped to a BCH (Broadcast Channel) or DLSCH, which is a transport channel.
- PCCH (Paging Control Channel): A logical channel for notifying paging information and system information changes. The PCCH is mapped to a PCH (Paging Channel), which is a transport channel.

Further, the mapping relationship between transport channels and physical channels is as follows.
- DLSCH and PCH: mapped to PDSCH (Physical Downlink Shared Channel). DLSCH supports HARQ, link adaptation, and dynamic resource allocation.
- BCH: Mapped to PBCH (Physical Broadcast Channel).

Next, FIG. 9 shows uplink channel mapping in the LTE system. Similar to FIG. 8, the mapping relationship between the logical channel (Downlink Logical Channel), the transport channel (Downlink Transport Channel), and the physical channel (Downlink Physical Channel) is shown. Below, they will be explained in order.

- CCCH (Common Control Channel): A logical channel used to transmit control information between the UE 5, the relay radio communication unit 9, and the EPC function unit 3, and is a logical channel used to transmit control information between the UE 5, the relay radio communication unit 9, and the EPC function unit 3, and the EPC function unit 3 and radio resources. Used by UE5 that does not have a control (RRC: Radio Resource Control) connection.
・DCCH (Dedicated Control Channel): A point-to-point bidirectional logical channel that transmits individual control information between the UE 5, the relay radio communication unit 9, and the EPC function unit 3. This is the channel used to transmit. The dedicated control channel DCCH is used by UE5s that have an RRC connection.
- DTCH (Dedicated Traffic Channel): A one-to-one bidirectional logical channel, which is dedicated to a specific UE or relay radio communication unit, and is used to transfer user information.

- It is a transport channel that supports ULSCH (Uplink Shared Channel: HARQ), dynamic adaptive radio link control, and discontinuous transmission (DTX).
- RACH (Random Access Channel): A transport channel on which limited control information is transmitted.

・PUCCH (Physical Uplink Control Channel): Response information for downlink data (ACK (Acknowledge)/NACK (Negative acknowledge)), downlink radio quality information (CQI), and uplink data This is a physical channel used to notify the wireless base station section 4 of a transmission request (scheduling request: SR).
- PUSCH (Physical Uplink Shared Channel): A physical channel used to transmit uplink data.
- PRACH (Physical Random Access Channel): A physical channel mainly used for random access preamble transmission to obtain transmission timing information (transmission timing command) from the UE 5 to the radio base station section 4. Random access preamble transmission is performed during the random access procedure.

As shown in FIG. 9, in the uplink, transport channels and physical channels are mapped as follows. The uplink shared channel ULSCH is mapped to the physical uplink shared channel PUSCH. Random access channel RACH is mapped to physical random access channel PRACH. The physical uplink control channel PUCCH is used as a physical channel alone. Further, the common control channel CCCH, dedicated control channel DCCH, and dedicated traffic channel DTCH are mapped to the uplink shared channel ULSCH.

Next, in the downlink of the LTE system, the UE 5 and the relay radio communication unit 9 wirelessly connect to the radio base station unit 4 using OFDM (Orthogonal Frequency-Division Multiplexing) access (OFDMA). The OFDMA system is characterized as a two-dimensional multiple access system that combines frequency division multiplexing and time division multiplexing. Specifically, orthogonal subcarriers on the frequency axis and time axis are divided and allocated to UE5, and the subcarriers that are orthogonal on the frequency axis are divided so that the signal of each subcarrier becomes zero (0 point). . By dividing subcarriers and allocating them on the frequency axis, even if one subcarrier is affected by fading, it is possible to select another subcarrier that is unaffected. This has the advantage that subcarriers can be used and wireless quality can be maintained.

In the OFDMA system, a resource block (hereinafter also referred to as RB) defined on a virtual plane extending between a frequency axis and a time axis is employed as a radio resource. As shown in Fig. 10, RB is defined as a block obtained by dividing the above plane into a matrix at 180 kHz/0.5 msec, and each block divides 12 adjacent subcarriers at 15 kHz intervals on the frequency axis, and Contains one slot (7 symbols) of the frame. These RBs are assigned to the UE 5 and the relay radio communication unit 9, with two RBs adjacent on the time axis (1 msec) as one set. On the other hand, in the uplink of the LTE system, resource blocks with a similar concept are used as radio resources, except that SC-FDM (Single Career Frequency-Division Multiplexing) access (SC-FDMA) is adopted. In OFDMA, one resource block is divided into 12 subcarriers (bandwidth: 15 kHz) on the frequency axis, whereas SC-FDMA is a single carrier system in which division into subcarriers is not performed.

For example, allocation of resource blocks to the downlink is determined using the following procedure in the normal LTE protocol. The UE 5 and the relay radio communication unit 9 receive the CQI reference signal transmitted from the eNodeB 4 for each predetermined frequency unit, measure the CQI, which is an indicator indicating the reception quality of the downlink channel, and create CQI information. . CQI information expresses the reception quality obtained through measurement using two parameters: coding rate and frequency utilization efficiency for each modulation method, and is transmitted from UE5 to eNodeB4 using the uplink control channel (PUCCH described above). Reported using CQI index.

The eNodeB 4 allocates a radio bearer with each UE 5 or the relay radio communication unit 9 based on the CQI information notified from the plurality of UEs 5 or the relay radio communication unit 9. By optimally allocating frequency blocks with high received signal levels to each UE 5 and relay radio communication unit 9 according to the content of CQI information of each UE 5 and relay radio communication unit 9, 9 diversity effect (multi-user diversity) can be obtained, and user throughput and throughput per cell can be improved.

FIG. 11 shows an example of the configuration of a wireless network system when the wireless communication unit 1 having the above configuration is adopted. In the wireless network system, wireless communication unit groups 1(A) to 1(D) are arranged into adjacent wireless communication unit pairs (1(A) and 1(B), 1(B) and 1(C), 1( C) and 1(D)) base station cells (50(A) and 50(B), 50(B) and 50(C), 50(C) and 50(D)) partially overlap. , are cascade-connected by inter-unit radio bearers 55(A), 55(B), and 55(C). With this configuration, it can be easily understood that the connection topology between the wireless communication units 1 is extremely simplified. In this case, for example, UE 5 (A) (mobile terminal) connected to one of the pair of wireless communication units 1 (A) and 1 (B) and UE 5 (B) (mobile terminal) connected to the other IP packets can be transmitted and received via the unit pair 1(A), 1(B) and the inter-unit radio bearer 55(A) that connects the wireless communication unit pair 1(A), 1(B). For example, all of the wireless communication unit groups 1(A) to 1(D) may be mounted on a moving body such as the above-mentioned ship or vehicle, or only some of them may be mounted on a moving body, The remaining parts may be fixedly installed inside a building or the like.

Further, in FIG. 11, the number of wireless communication units cascade-connected by inter-unit radio bearers 55(A), 55(B), and 55(C) is three or more (four in FIG. 11). In this case, a UE (mobile terminal) 5 (A) connected to the first wireless communication unit 1 (A) forming one wireless communication unit of the wireless communication unit groups 1 (A) to 1 (D) and a wireless In communication unit groups 1(A) to 1(D), a second wireless communication unit disposed with one or more intermediate wireless communication units 1(B) and 1(C) separated from the first wireless communication unit 1(A) The UEs (mobile terminals) 5(C), 5(D) connected to the wireless communication units 1(C), 1(D) are connected to the first wireless communication unit 1(A), the intermediate wireless communication unit 1(B), 1(C) and second wireless communication units 1(C), 1(D), and an inter-unit radio bearer 55(A) that connects these wireless communication units 1(A) to 1(D). ), 55(B), and 55(C). In this way, the number of cascade-connected wireless communication units can be easily increased, and it becomes possible to transmit and receive IP packets by wireless communication between UE5s in a wider area.

In the wireless communication system according to the 3GPP specifications, any one of a plurality of frequency bands defined by the 3GPP is assigned. The assigned frequency bands differ depending on the communication method, and for example, bands 1, 3, 6, 8, 11, 18, 19, 21, 26, 28, 41, and 42 are used as LTE bands. Each band is divided into a plurality of frequency channels with a predetermined bandwidth, and the EPC function unit 3 selects a predetermined frequency channel for the inter-unit radio bearer 55 and the terminal radio bearer 57 in FIG. It will be constructed as follows. That is, the downstream inter-unit channel, the upstream inter-unit channel, and the terminal-side channel are each set as a frequency channel belonging to one of a plurality of bands defined by 3GPP.

In the present embodiment, the EPC function unit 3 fixes the setting frequency channel of the (downstream) inter-unit radio bearer 55 to a (downstream) inter-unit channel that is one specific predetermined frequency channel. Furthermore, the terminal side channel, which is the set frequency channel of the terminal radio bearer 57, is set to the same frequency channel as the (downstream) inter-unit channel. That is, the EPC function section 3 sets the same frequency channel for the wireless base station section 4 directly below the relay wireless communication section 9 of the wireless communication unit 1 on the downstream side and the mobile terminal 5.

Next, in FIG. 11, what are cell 50 (A) of wireless communication unit 1 (A), cell 50 (B) of wireless communication unit 1 (B), and cell 50 (C) of wireless communication unit 1 (C)? They overlap with each other. In this case, for example, the inter-unit channel of the inter-unit radio bearers 55 (A), (B) connecting the upstream and downstream radio communication units 1 (A), 1 (C) as seen from the radio communication unit 1 (B) is By setting these to mutually different frequency channels, when constructing the inter-unit radio bearers 55(A) and (B), a plurality of cells 50(A) to 50(C) that partially overlap each other are connected to each other. It is possible to effectively prevent radio wave interference between

More specifically, each EPC function unit 3 of the wireless communication units 1(A) to 1(D) converts the downstream inter-unit channel into the upstream inter-unit radio when the (upstream) inter-unit radio bearer is constructed. The frequency channel is set to be different from the upstream inter-unit channel set for the bearer, while the terminal channel group is set as a frequency channel group different from both the downstream inter-unit channel and the upstream inter-unit channel. For example, when focusing on the wireless communication unit 1 (B), the EPC function section 3 of the wireless communication unit 1 (B) controls the upstream inter-unit channel set for the upstream inter-unit radio bearer 55 (B). For example, set it to CH2. On the other hand, the EPC function section 3 of the wireless communication unit 1 (A) is configured to provide an upstream inter-unit radio bearer 55 (A) as seen from the wireless communication unit 1 (A) (a downstream unit inter-unit radio bearer as seen from the wireless communication unit 1 (B)). The upstream inter-unit channel (which is the downstream inter-unit channel when viewed from the wireless communication unit 1 (B)) that is set for the radio bearer) is set to CH1, which is different from CH2. At this time, by setting the downstream inter-unit channel CH1 and the upstream inter-unit channel CH2 as mutually different frequency channels within the same band, the radio base station part 4 and the relay radio communication part 9 for constructing the inter-unit radio bearer are There is an advantage that the hardware can be easily configured with a single band specification. Furthermore, the terminal side channel is set to the same channel as the downstream inter-unit channel among the frequency channels belonging to the same band.

Furthermore, in this embodiment, the band 28 defined by 3GPP is adopted as the same band. Band 28 is set to the VHF band (700 MHz band), which has become vacant due to the discontinuation of terrestrial analog television broadcasting. Because Band 28 is a low frequency band and has somewhat slow communication speeds, it has not been actively adopted in areas with many terminal subscribers, such as urban areas, and the usage of radio wave resources is not as tight. Therefore, you can expect a smooth connection. Furthermore, the use of a low frequency band means that radio waves can reach long distances, and it is possible to expand the area (cell) that can be covered by one wireless communication unit. Furthermore, it has the property of being easy to connect even underground or when there are obstacles, and can be said to be suitable for constructing the wireless network system of the present invention, for example, on the sea or in a mine.

The flow of the attach sequence between the relay wireless communication unit 9 and the UE 5 will be described below with reference to FIGS. 12 and 13. FIG. 12 shows the attach sequence of the relay wireless communication unit 9. In the TS1, an attach request is issued from the relay radio communication unit 9 to the MME 2 via the radio base station unit (eNodeB) 4. By receiving the broadcast signal periodically output from the eNodeB4, the relay radio communication unit 9 can recognize that it has entered the cell (that is, within range) of the eNodeB4, and outputs an attach request to the eNodeB4. At this time, the IP address of the wireless communication unit is transmitted to the request source. In response to this, MME2 transmits a bearer setting request to S-GW6 in TS2. The S-GW 6 executes a physical line bearer setting process on the S5 interface with the P-GW 7 in TS3. Once the bearer is set up, the S-GW 6 transmits a bearer setup response to the MME 2 in TS4.

The MME 2 acquires the channel number that the requesting unit is using for the downstream inter-unit radio bearer in TS5, and in TS6 sends a radio bearer configuration request (attach acceptance) to the radio base station 4 with the configured channel number (obtained). the number of the adjacent channel). Upon receiving this, the radio base station unit 4 transmits an MIB (Master Information Block) including the setting channel number of the radio bearer (inter-unit radio bearer) to be set in TS7 to the relay radio communication unit 9. At TS8, the relay wireless communication section 9 fixes the inter-unit channel to the set channel number included in the received MIB, and returns a setting completion notification. In response to this, the wireless base station unit 4 notifies the relay wireless communication unit 9 of a session start request (attach acceptance) at TS9. At TS10, the relay radio communication section 9 sets up an inter-unit radio bearer and returns a session start response to the radio base station section 4. At TS11, the wireless base station unit 4 notifies the MME 2 of a session start response.

On the other hand, FIG. 13 shows the attach sequence of UE5 (mobile terminal). In the TS 11', an attach request is issued from the UE 5 to the MME 2 via the radio base station section (eNodeB) 4. At this time, the IP address of the wireless communication unit is transmitted to the request source. In response to this, MME2 transmits a bearer setting request to S-GW6 in TS12. In TS13, the S-GW 6 executes a physical line bearer setting process on the S5 interface with the P-GW 7. If the bearer is set up, the S-GW 6 transmits a bearer setting response to the MME 2 in TS14. The MME 2 determines a set channel number that can be used as a terminal radio bearer group according to the process shown in FIG. 13 . Then, at TS16, a radio bearer setup request (attach acceptance) is notified to the radio base station unit 4 along with the determined setup channel number. Upon receiving this, the radio base station section 4 transmits an MIB (Master Information Block) including the setting channel number of the radio bearer (inter-unit radio bearer) to be set in TS17 to the UE5. If there is a relay radio communication section of another radio communication unit connected to the radio base station section 4, the same channel number as that of the relay radio communication section 9 is used as this set channel number.

At TS18, the UE 5 sets the terminal side channel to the setting channel number included in the received MIB, and returns setting completion. In response to this, the radio base station unit 4 notifies the UE 5 of a session start request (attach acceptance) at TS19. At TS20, the UE 5 sets up a terminal radio bearer and returns a session start response to the radio base station section 4. At TS21, the wireless base station unit 4 notifies the MME 2 of a session start response. As described above, the attach sequence of the UE 5 and the attach sequence of the relay radio communication unit 9 are executed according to basically the same procedure except for the content of the frequency channel setting.

Next, each of the wireless communication units 1(A) to 1(D) in FIG. 11 has a built-in router 8, and is connected to an external network 60 (for example, the global public network (Internet)) via a satellite communication line 61 or the like. It is possible. With this configuration, it is also possible to transfer IP packets whose destination is a network outside the wireless network system of the present invention.

As shown in FIG. 2, in the present invention, the number of wireless communication bearers to be constructed simultaneously between a wireless communication unit pair consisting of an arbitrary wireless communication unit 1 (A) and a wireless communication unit 1 (B) is set to 2. These two inter-unit radio bearers 55(P) and 55(S) form a radio backhaul. Hereinafter, a case where the wireless communication unit 1 (B) becomes the backhaul construction destination wireless communication unit from the viewpoint of the wireless communication unit 1 (A) will be described as an example. In this case, the relay wireless communication section 9 (A) of the wireless communication unit 1 (A) establishes a wireless communication bearer with the wireless base station section 4 (B) of the wireless communication unit 1 (B) using the first inter-unit wireless Bearer 55 (P), and the relay wireless communication unit 9 (B) of the wireless communication unit 1 (B) (backhaul construction destination wireless communication unit) communicates with the wireless base station unit 4 (A) of the wireless communication unit 1 (A). The radio communication bearer constructed between the two units is referred to as the second inter-unit radio bearer 55(S). The wireless communication unit (upstream unit) that connects to the relay wireless communication section 9 (A) of the wireless communication unit 1 (A) is the first external wireless communication unit, and the wireless communication unit that also connects to the wireless base station section 4 (A). Although the communication unit (downstream unit) is the second external wireless communication unit, in the state of FIG. 2 where the wireless backhaul is constructed, the first external wireless communication unit and the second external wireless communication unit are both wireless communication units. 1(B) and the substance is the same.

The first inter-unit radio bearer 55 (P) and the second inter-unit radio bearer 55 (S) are connected to the relay radio communication section 9 (A) by the radio base station section 4 ( B) is constructed by attaching the relay wireless communication section 9 (B) to the wireless base station section 4 (A). Then, the EPC function section 3 (A) of the wireless communication unit 1 (A) transmits the relay wireless communication section 9 (A) to at least one of the relay wireless communication section 9 (A) and the wireless base station section 4 (A). A first inter-unit radio bearer 55 (P) is established between the wireless base station section 4 (B) of the backhaul construction destination wireless communication unit (wireless communication unit) 1 (B), and the wireless base station section 4 (A ), by similarly constructing a second inter-unit radio bearer 55 (S) with the relay radio communication unit 9 (B), the backhaul construction target radio communication unit (wireless communication unit) 1 (B) A control command is issued to construct a wireless backhaul consisting of the first inter-unit radio bearer 55 (P) and the second inter-unit radio bearer 55 (S). This process is carried out by the aforementioned wireless backhaul construction control command program 305r.

Here, the technical significance of the EPC function unit 3 issuing a control command to construct a wireless backhaul to “at least one” of the relay wireless communication unit 9 (A) and the wireless base station unit 4 (A) is , includes the following three cases.
(1) In the case where the first inter-unit radio bearer 55 (P) has already been constructed between the relay radio communication unit 9 (A) and the radio base station unit 4 (B), the relay radio communication unit 9 (B) and the radio A second inter-unit radio bearer 55 (S) is newly established with the base station section 4 (A) to form a radio backhaul. In this case, a control command for constructing a wireless backhaul is output to the wireless base station section 4(A). Note that the wireless communication unit 1 (B) serving as the backhaul construction destination wireless communication unit corresponds to the first external wireless communication unit (upstream unit) when it is independently connected to the relay wireless communication unit 9 (A).
(2) In the case where the second inter-unit radio bearer 55 (S) has already been constructed between the relay radio communication unit 9 (B) and the radio base station unit 4 (A), the relay radio communication unit 9 (A) and the radio A first inter-unit radio bearer 55 (P) is newly constructed with the base station section 4 (B) to form a radio backhaul. In this case, a control command for constructing a wireless backhaul is output to the relay wireless communication section 9(A). Note that the wireless communication unit 1 (B) serving as the backhaul construction destination wireless communication unit corresponds to a second external wireless communication unit when it is independently connected to the wireless base station section 4 (A).
(3) In a case where no inter-unit radio bearer is formed between the relay radio communication section 9 (A) and the radio base station section 4 (B), between the first inter-unit radio bearer 55 (P) and the second unit Radio bearers 55(S) are sequentially constructed to form a radio backhaul. In this case, a control command for constructing a wireless backhaul is output to both the relay wireless communication section 9(A) and the wireless base station section 4(A).

First, the flow of processing in case (1) will be explained with reference to the communication flow diagram in FIG. 14 and the explanatory diagrams in FIGS. 15 and 16. In LA1, wireless communication unit 1 (A) transmits an attach request to wireless communication unit 1 (B) (backhaul construction destination wireless communication unit), and wireless communication unit 1 (B) ) accepts this, the attach sequence of FIG. 12 is executed in LA2, and the first inter-unit radio bearer 55 (P) is constructed using a specific frequency channel (for example, CH1) (upper part of FIG. 15). .

Subsequently, when the wireless communication unit 1 (A) connects to the external network 60 (in this embodiment, the Internet (public network)) through the router 8 (FIG. 3) (bottom of FIG. 15), the wireless communication unit 1 The mobile terminals 5 currently connected to the wireless base station section 4 (A) in (A) can each connect to the external network 60 via the wireless communication unit 1 (A). On the other hand, the mobile terminal 5 connected to the radio base station section 4 (B) of the radio communication unit 1 (B) (backhaul construction target radio communication unit) is connected to the radio communication unit 1 (B) → first inter-unit radio bearer 55 Access to the external network 60 becomes possible via the route (P)→wireless communication unit 1 (A). When a plurality of mobile terminals 5 connected to the wireless communication unit 1 (B) access the Internet (external network 60) at the same time, all information exchanged through the access passes through the first inter-unit radio bearer 55 (P). Therefore, if the communication traffic of the first inter-unit radio bearer 55(P) increases excessively, problems such as congestion will occur.

Therefore, the EPC function section 3 (A) of the wireless communication unit 1 (A) checks whether an Internet connection via the router 8 (for example, a connection via a communication satellite line, etc.) has been established at LA 3 in FIG. 14. Check whether or not. If it is not connected, LA3 continues the process of monitoring whether or not there is an Internet connection. On the other hand, if the Internet connection is established as shown in the lower part of FIG. 15, the process proceeds to LA4 and notifies the wireless communication unit 1 (B) (backhaul construction destination wireless communication unit) of a wireless backhaul construction request (the upper part of FIG. 16). ). In response to this, the wireless communication unit 1 (B) issues an attach request to the wireless communication unit 1 (A) at LA5 (see FIG. 16). Then, in the LA 6, the attach sequence of FIG. 12 is executed, and the second inter-unit radio bearer 55(S) is constructed using a different frequency channel (for example, CH2) from the first inter-unit radio bearer 55(P). (Figure 16 bottom).

The first inter-unit radio bearer 55 (P) and the second inter-unit radio bearer 55 (S) form a link aggregation, and when the first inter-unit radio bearer 55 (P) is formed alone (Fig. 15 Compared to the above), the two frequency channels CH1 and CH2 provide a wireless backhaul with twice the communication bandwidth. Thereby, problems such as congestion caused by communication traffic congestion between the wireless communication unit 1 (B) and the wireless communication unit 1 (A) due to an increase in Internet access in the wireless communication unit 1 (B) can be effectively resolved.

Next, the flow of processing in case (2) will be explained with reference to the communication flow diagram in FIG. 17 and the explanatory diagrams in FIGS. 18 and 19. In LA51, wireless communication unit 1 (B) (backhaul construction target wireless communication unit) transmits an attach request to wireless communication unit 1 (A), and wireless communication unit 1 (A) accepts this, thereby attaching LA52. The attach sequence of FIG. 12 is executed, and the second inter-unit radio bearer 55(S) is constructed using a specific frequency channel (for example, CH2) (upper part of FIG. 18).

Next, the wireless communication unit 1(A) checks whether an Internet connection has been established via the router 8 at the LA 53 in FIG. 17. If it is not connected, the LA 53 continues the process of monitoring whether or not there is an Internet connection. On the other hand, if the Internet connection is established as shown in the lower part of FIG. 18, the process proceeds to the LA 54, and an attach request is made to the wireless communication unit 1 (B) (backhaul construction target wireless communication unit) (upper part of FIG. 19). Then, in the LA 55, the attach sequence of FIG. 12 is executed, and the first inter-unit radio bearer 55 (P) is constructed using a different frequency channel (for example, CH1) from the second inter-unit radio bearer 55 (S). (Figure 19 bottom). In this case as well, a wireless backhaul is formed in exactly the same way as in the lower part of FIG. 16, and the same effect is achieved.

Finally, in the case of (3) above, the Internet connection is established in the wireless communication unit 1 (A) first, and the inter-unit radio bearer with the wireless communication unit 1 (B) is not available at that point. Not built. Therefore, when the wireless communication unit 1 (B) approaches the wireless communication unit 1 (A) and reaches a distance where they can be attached to each other (that is, when the respective cells overlap), , an attach request is issued from one of the wireless communication unit 1(A) and the wireless communication unit 1(B) to the other, and the first inter-unit radio bearer 55(P) and the second unit are attached according to the attach sequence of FIG. One of the intervening radio bearers 55(S) is first established.

Next, the wireless communication unit 1 (A) is currently connected to the Internet, and in this state attaches itself to the wireless communication unit 1 (B) to establish a first inter-unit radio bearer 55 (P). If so, the second inter-unit radio bearer 55(S) is constructed in exactly the same procedure as the processing from LA4 onwards in FIG. 14, and a radio backhaul is formed. On the other hand, when the second inter-unit radio bearer 55 (S) is constructed in response to the attach from the wireless communication unit 1 (B), the first inter-unit radio A bearer 55(P) is established and a wireless backhaul is formed.

Note that in any of the above cases, when forming a wireless backhaul, it is a necessary condition that a connection with the Internet is established in the wireless communication unit 1 (A). If establishment of a connection with the Internet is confirmed, processing for forming a wireless backhaul is immediately executed (that is, establishment of an Internet connection is a necessary and sufficient condition for forming a wireless backhaul). However, establishing an Internet connection is only a necessary condition for forming a wireless backhaul. A further requirement is that the number of mobile terminals 5 connected to the wireless base station section of one external wireless communication unit (in case of (2), the wireless base station section of the second external wireless communication unit) exceeds a threshold. It is also possible to set it as a condition. In this case, radio backhaul formation will be performed only when traffic congestion of inter-unit radio bearers is expected.

At this time, the EPC function section 3 (A) of the wireless communication unit 1 (A) transmits information on the number of connections of the mobile terminal to the wireless base station section of the first external wireless communication unit or the wireless base station section of the second external wireless communication unit. It is assumed that the device is equipped with a terminal connection number acquisition section. Specifically, when wireless communication unit 1 (A) connects to the Internet, the number of mobile terminals that are currently connected from wireless communication unit 1 (B) using the previously constructed inter-unit radio bearer. get. If the number of connections exceeds a predetermined threshold, as shown in the upper part of Figure 20, a wireless backhaul is formed according to the same procedure as described above, as shown in the lower part of Figure 20. Bye. As a result, while the number of terminals connected to the wireless communication unit 1 (B) is less than the threshold, the number of inter-unit radio bearers established with the wireless communication unit 1 (A) is maintained at only one, and the wireless Room is reserved for communication unit 1 (A) or wireless communication unit 1 (B) to connect with other wireless communication units.

Although the embodiments of the present invention have been described above, they are merely examples, and the present invention is not limited thereto. For example, in the radio communication units 1'(A) and 1'(B) shown in FIG. 21, a plurality of radio base stations 4( AX), 4 (AY) and 4 (BX), 4 (BY). In the state of FIG. 21, a first inter-unit radio bearer is established between the radio base station section 4 (AY) of the radio communication unit 1' (A) and the relay radio communication section 9 (B) of the radio communication unit 1' (B). 55 (P) is a second inter-unit radio bearer between the radio base station section 4 (BX) of the radio communication unit 1' (B) and the relay radio communication section 9 (A) of the radio communication unit 1' (A). 55(S) has been constructed and a wireless backhaul is being formed. In this case, the wireless base station section 4 (AX) of the wireless communication unit 1' (A) and the wireless base station section 4 (BY) of the wireless communication unit 1' (B) are separated from each other. It is possible to construct inter-unit radio bearers. FIG. 22 shows that the wireless base station section 4 (BY) of the wireless communication unit 1' (B) communicates with the relay wireless communication section 9 (C) of another wireless communication unit 1' (C) and a unit that is not involved in wireless backhaul. This shows an example in which the wireless bearer 55 (P) (CH3) is used for connection.

In addition, although the formation of the wireless backhaul was executed with the Internet connection of the wireless communication unit 1 (A) as a necessary condition in the above embodiment, the wireless communication unit 1 (A) in the configuration that does not require the Internet connection, for example, 1(A) is connected to a data server (for example, a video server: not shown), and accesses to this video server from the wireless communication unit 1(B) are concentrated, the same method as above is applied. Forming a wireless backhaul is effective. In this case, for example, if the data distribution period from the video server is predetermined, it is possible to form a wireless backhaul in accordance with the data distribution period when accesses to the video server are concentrated.

1(A), 1(B) Wireless communication unit WS(A), WS(B) Large ship 2 MME
3 EPC function section 301 CPU
302 RAM
303 Mask ROM
304A Upstream communication interface 304B Downstream communication interface 305 Flash memory 305a Communication firmware 305b MME entity 305c S-GW entity 305d P-GW entity 305r Wireless backhaul construction control command program 306 Bus 21 Secondary battery module 22 Power supply circuit section 23 Possible Portable casings 30, 31 Communication bus 4 Wireless base station section 401 CPU
402 RAM
403 Mask ROM
404 Communication interface 405 Flash memory 405a Communication firmware 406 Bus 412 Wireless communication unit 5 UE (mobile terminal)
6 S-GW
7 P-GW
8 Router 9 Relay wireless communication section 901 CPU
902 RAM
903 Mask ROM
905 Flash memory 905a Communication firmware 906 Bus 912 Wireless communication units 50 (A), 50 (B) Cells 55 (P), 55 (S) Inter-unit radio bearer 57 Radio bearer for terminal

Claims (7)

A wireless communication unit configured to be mounted on a mobile body and for performing wireless network communication with a mobile terminal,
a radio base station unit to which the mobile terminal can connect via a terminal radio bearer;
an EPC (Evolved Packet Core) functional unit that is connected by wire to the wireless base station unit and functions as an upper network control unit for the wireless base station unit;
a relay wireless communication unit that is connected by wire to the EPC function unit and connectable to the wireless base station unit of the first external wireless communication unit via a first inter-unit radio bearer;
The radio base station section is connectable to a relay radio communication section of a second external radio communication unit via a second inter-unit radio bearer,
The EPC function unit uses the same external wireless communication unit that is shared by the first external wireless communication unit and the second external wireless communication unit as a backhaul construction destination wireless communication unit, and the EPC function unit uses the same external wireless communication unit that is shared by the first external wireless communication unit and the second external wireless communication unit as a backhaul construction destination wireless communication unit. For at least one of the radio base station sections, for the relay radio communication section, the first inter-unit radio bearer is provided between the radio base station section of the backhaul construction target radio communication unit, and for the radio base station section. In order to construct the second inter-unit radio bearer between the relay radio communication unit of the backhaul construction destination wireless communication unit, the first inter-unit wireless communication unit is connected to the backhaul construction destination wireless communication unit. A wireless communication unit comprising a wireless backhaul construction control command unit that issues a control command to construct a wireless backhaul consisting of a bearer and a second inter-unit radio bearer. The wireless backhaul construction control command unit is configured to provide a wireless backhaul to the relay wireless communication unit in a state where the wireless base station unit is connected to the relay wireless communication unit of the external wireless communication unit by the second inter-unit radio bearer. It is used to issue construction control commands.
The relay wireless communication unit is configured to construct the first inter-unit radio bearer by making an attach request to the wireless base station unit of the first external wireless communication unit upon receiving the control command for constructing the wireless backhaul. 1. The wireless communication unit according to 1. The wireless backhaul construction control command unit is configured to provide wireless backhaul to the wireless base station while the relay wireless communication unit is connected to the wireless base station of the first external wireless communication unit by the first inter-unit radio bearer. It is used to issue hall construction control commands.
Upon receiving the control command for wireless backhaul construction, the wireless base station section transmits a backhaul construction request to the relay wireless communication section of the second external wireless communication unit, and also transmits a backhaul construction request to the relay wireless communication section of the second external wireless communication unit. The wireless communication unit according to claim 1 or 2, wherein the second inter-unit radio bearer is constructed by receiving an attach request as a response to the backhaul construction request from the wireless communication section. A router is provided to relay transmission and reception of IP packets between the EPC function unit and an external network,
The wireless backhaul construction control command unit instructs at least one of the relay wireless communication unit and the wireless base station unit to construct the wireless backhaul, with the necessary condition that a public network is connected to the router as the external network. The wireless communication unit according to any one of claims 1 to 3, wherein the wireless communication unit issues the control command. The EPC function unit includes a terminal connection number acquisition unit that acquires information on the number of connections of the mobile terminal to the wireless base station unit of the first external wireless communication unit or the wireless base station unit of the second external wireless communication unit, The wireless backhaul construction control command unit is configured to instruct at least one of the relay wireless communication unit and the wireless base station unit to configure the wireless backhaul, with the necessary condition that the number of connections exceeds a predetermined threshold. 5. The wireless communication unit according to claim 4, wherein the wireless communication unit issues a control command. A wireless communication unit configured to be mountable on a mobile body and for performing wireless network communication with a mobile terminal, the wireless base station unit being connectable to the mobile terminal via a terminal radio bearer; an EPC (Evolved Packet Core) functional section that is connected by wire to the wireless base station section and functions as an upper network control section for the wireless base station section; and a wireless base of the first external wireless communication unit that is connected to the EPC functional section by wire and serves as an upper network control section for the wireless base station section. a relay radio communication section connectable to the local station via a first inter-unit radio bearer; the radio base station section connectable to the relay radio communication section of a second external radio communication unit via a second inter-unit radio bearer; The EPC function unit uses the same external wireless communication unit shared by the first external wireless communication unit and the second external wireless communication unit as a backhaul construction destination wireless communication unit, and the EPC function unit For at least one of the relay radio communication unit and the radio base station unit, the relay radio communication unit is configured to provide the first inter-unit radio bearer between the relay radio communication unit and the radio base station unit of the backhaul construction target radio communication unit; For the radio base station section, in order to construct the second inter-unit radio bearer between the relay radio communication section of the backhaul construction destination wireless communication unit, a pair of wireless communication units provided with a wireless backhaul construction control command unit that issues a control command to construct a wireless backhaul consisting of the first inter-unit radio bearer and the second inter-unit radio bearer;
The relay radio communication unit of one of the pair of radio communication units and the radio base station unit of the other are connected by the first inter-unit radio bearer, and the radio base station unit of one of the pair of radio communication units and the relay radio communication unit of the other of the pair of radio communication units are connected. The wireless network system is characterized in that the wireless backhaul is constructed between a pair of the wireless communication units by connecting the two units with the second unit-to-unit radio bearer. At least one of the pair of wireless communication units is provided with a router that relays transmission and reception of IP packets between the EPC function section and an external network, and a public network is connected to the router as the external network. 6. The wireless network system according to 6.

Images