JP7341735B2 - 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)), EPC (Evolved Packet Core) that accommodates the wireless communication access network is The wireless base station to which mobile terminals connect is controlled to send and receive IP packets via the EPC.On the other hand, with the spread of mobile terminals such as mobile phones, smartphones, and tablet PCs, You want to use your mobile terminal even in areas where EPC and wireless base stations are not well-developed (hereinafter referred to as "wireless undeveloped areas"), such as in depopulated areas, areas where communication functions have been lost due to disasters, etc. There is a growing demand for this.

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 communication area that can be covered by one wireless communication unit is narrow, 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). Other than the above-mentioned offloading via the satellite device, there is no specific disclosure in the literature as to what kind of entity this connection is made of. However, if we assume that wireless communication units are connected by wire, if we try to distribute the wireless communication units in a relatively wide communication area in an area without wireless infrastructure, the communication cables that connect the devices It becomes very long. 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. Furthermore, if it is assumed that wireless communication units are also wirelessly connected, no consideration is given to the connection topology of the wireless communication units when covering a wide communication area with a plurality of wireless communication units.

An object of the present invention is to make it possible to wirelessly link multiple wireless communication units with a simple structure, thereby easily realizing cooperative operation between multiple units, and to make the connection topology between the wireless communication units more flexible. An object of the present invention is to provide a configurable wireless communication unit 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. 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 the wireless base station section of the upstream unit (hereinafter referred to as the upstream wireless base station section), which is a first another wireless communication unit, and the upstream inter-unit radio bearer (hereinafter referred to as the upstream inter-unit radio bearer). The wireless base station unit is equipped with a relay wireless communication unit that can be connected to a downstream unit, which is a second separate wireless communication unit (hereinafter referred to as “downstream relay wireless communication unit”), and a downstream unit. Connection is possible via a radio bearer (hereinafter referred to as a downstream inter-unit radio bearer), and the EPC function section sends a downstream inter-unit radio bearer setting request to the radio base station section, while the radio base station section performs downstream inter-unit radio bearer setting. In response to a request, the EPC function unit constructs a downstream inter-unit radio bearer together with the downstream relay radio communication unit, and the EPC function unit transmits a terminal radio bearer setting request to the radio base station unit, while the radio base station unit configures the terminal radio bearer setting. Upon receiving a request, the relay radio communication unit constructs a terminal radio bearer together with the mobile terminal, and the relay radio communication unit receives an inter-upstream unit radio bearer setting request issued by the EPC function unit of the upstream unit (hereinafter referred to as the “upstream EPC function unit”). and constructs an upstream inter-unit radio bearer together with the upstream radio base station in response to the upstream unit-to-unit radio bearer setting request. It is characterized in that it can be connected via an inter-downstream unit radio bearer that corresponds one-to-one with downstream units.

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 unit that can be connected to a radio base station unit of an upstream unit (hereinafter referred to as an upstream radio base station unit) which is another radio communication unit of the upstream unit via an upstream inter-unit radio bearer (hereinafter referred to as an upstream inter-unit radio bearer). The radio base station unit includes a relay radio communication unit of a downstream unit (hereinafter referred to as a downstream relay radio communication unit), which is a second separate radio communication unit, and a downstream inter-unit radio bearer (hereinafter referred to as a downstream unit inter-unit radio bearer). The EPC function section sends a downstream inter-unit radio bearer setting request to the radio base station section, while the radio base station section receives the downstream inter-unit radio bearer setting request and performs downstream relay radio communication. The EPC function unit constructs a downstream inter-unit radio bearer together with the mobile terminal, and the EPC function unit sends a terminal radio bearer setting request to the radio base station unit, while the radio base station unit receives the terminal radio bearer setting request and constructs the terminal radio bearer together with the mobile terminal. The relay radio communication unit receives an upstream unit-to-unit radio bearer setting request issued by an upstream unit's EPC function unit (hereinafter referred to as upstream EPC function unit), and constructs an upstream unit-to-unit radio bearer. Upon receiving a bearer setting request, the radio base station constructs an upstream inter-unit radio bearer together with the upstream radio base station , and the radio base station also allows the relay radio communication sections of multiple downstream units to correspond one-on-one to those downstream units. A wireless communication unit is configured by arranging a plurality of wireless communication units, a wireless communication unit group is configured by arranging a plurality of wireless communication units , and a wireless communication unit group is configured such that connection is possible via a radio bearer between downstream units. is a mobile terminal that is connected by the inter-unit radio bearer in a positional relationship in which the base station cells of a pair of radio communication units that are configured by mutually adjacent radio communication units partially overlap, and is connected to one of the pair of radio communication units. and a mobile terminal connected to the other transmit and receive IP packets via a pair of wireless communication units and an inter-unit radio bearer connecting the pair of wireless communication units.

In the wireless communication unit (and wireless network system) of the present invention, in its subordinate concept, when the relay wireless communication unit detects a candidate for an upstream unit to be a new connection destination in a state where the upstream unit is not connected, By transmitting an attach request for constructing an upstream inter-unit radio bearer to the radio base station section of the upstream unit candidate, an upstream inter-unit radio bearer setting request is received from the upstream unit candidate, and the upstream inter-unit radio bearer is established. It can be configured to include an upstream unit-to-unit radio bearer construction control section that controls the construction of the upstream unit.

Further, the radio base station section can be configured such that the relay radio communication sections of a plurality of downstream units can be connected to one radio base station section at the same time. In this case, the relay radio communication sections of the plurality of downstream units can be configured to be simultaneously connected to one radio base station section by downstream inter-unit radio bearers set on the same frequency channel. Further, when the radio base station section receives an attach request from a candidate for a newly connected downstream unit in a state where the number of connected downstream units is one or less, the radio base station section notifies the EPC function section of the attach request, and It can be configured to include a downstream inter-unit radio bearer construction control section that receives a terminal radio bearer setting request from the EPC functional section and performs control to construct a downstream inter-unit radio bearer with a downstream unit candidate. .

On the other hand, the wireless communication unit of the present invention can be configured such that a plurality of wireless base station sections are connected to one EPC function section, and each of the wireless base station sections can be connected to a relay wireless communication section of a downstream unit. In this case, the relay wireless communication units of the downstream units can be configured to be connected to a plurality of wireless base station units connected to one EPC functional unit by downstream inter-unit radio bearers set on mutually different frequency channels. . Further, when the wireless base station section receives an attach request from a candidate for a newly connected downstream unit while the downstream unit is not connected, the radio base station section notifies the EPC function section of the attach request, and The configuration may include a downstream inter-unit radio bearer construction control section that receives a terminal radio bearer setting request from the downstream unit candidate and performs control to construct a downstream inter-unit radio bearer with a downstream unit candidate.

If there is a switching candidate unit that is a wireless communication unit different from the upstream unit and can be wirelessly connected with higher quality than the upstream unit, the relay wireless communication unit connects to the switching candidate unit as a new upstream unit. It can be configured to include an upstream unit connection switching control section for switching.

Further, the upstream unit connection switching control section can be configured to switch the connection to the switching candidate unit when the connection with the upstream unit is cut due to a decrease in communication quality between the upstream unit and the upstream unit.

The EPC function section includes a downstream inter-unit radio bearer forced disconnection instruction section that instructs the radio base station section to temporarily and forcibly disconnect the downstream inter-unit radio bearer with the downstream unit. The upstream unit connection switching control section includes a downstream inter-unit radio bearer disconnection control section that performs disconnection control of the downstream inter-unit radio bearer in response to an instruction, and an upstream unit connection switching control section that disconnects the upstream inter-unit radio bearer when the upstream inter-unit radio bearer is disconnected. The communication quality of the old upstream unit, which is the wireless communication unit that was connected as the upstream unit by the bearer, and the switching candidate unit are evaluated, and the wireless communication that should be connected as the new upstream unit based on the results of the communication quality evaluation is performed. Can be configured to determine units. In this case, more specifically, the upstream unit connection switching control section receives a CQI reference signal from each wireless communication unit, generates CQI information using the CQI reference signal, and communicates based on the content of the CQI information. It can be configured to perform quality evaluation. In addition, if the number of connections of downstream units to the wireless communication unit to which the EPC function unit belongs has reached a predetermined upper limit, the EPC function unit transmits a forced disconnection instruction unit for the downstream unit radio bearer to the wireless communication unit to which the EPC function unit belongs. While issuing an instruction to temporarily and forcibly disconnect a radio bearer, if the number of connected downstream units is less than the upper limit number, it can be configured to allow additional downstream units to be connected.

In addition, the downstream unit inter-unit radio bearer forced disconnection instruction section includes a downstream unit distance information acquisition section that acquires downstream unit distance information that reflects the distance to the connected downstream unit, and a switching candidate that reflects the distance to the switching candidate unit. The distance d1 between the switching candidate unit distance information acquisition unit that acquires the unit distance information and the switching candidate unit reflected in the acquired switching candidate unit distance information is the distance d1 between the switching candidate unit that is reflected in the acquired downstream unit distance information and the downstream unit that is reflected in the acquired downstream unit distance information. When the distance dc becomes smaller than the distance dc, an instruction can be issued to temporarily and forcibly disconnect the downstream inter-unit radio bearer.

A current position acquisition unit that acquires the current position of the wireless communication unit is provided, and the downstream unit distance information acquisition unit and the switching candidate unit distance information acquisition unit acquire the current positions of the downstream unit and the switching candidate unit, and It can be configured to calculate the distances to the upstream and downstream units and the distances to the switching candidate unit, respectively, based on current position information. Further, the downstream inter-unit radio bearer forced disconnection instruction section may be configured to periodically output an instruction to disconnect the downstream inter-unit radio bearer at predetermined time intervals.

Furthermore, the EPC function unit connects the relay radio communication units of a plurality of mobile terminals and other radio communication units that are connected to the radio base station via the terminal radio bearer within the communication area of the radio base station unit. The device is equipped with a connected node registration unit that registers node identification information of mobile terminals in the wireless base station unit, and compares the destination node of the IP packet transferred from the wireless base station unit with the registered contents of the connected node registration unit, and determines whether the destination node is the destination node. , when indicating a mobile terminal corresponding to any of the node identification information registered in the connected node registration unit, the IP packet is forwarded to the mobile terminal by loopback at the wireless base station unit, while the destination node When indicating a node that is not registered in the connected node registration section, the IP packet can be configured to be controlled to be transferred from at least one of the relay wireless communication section and the wireless base station section to a destination outside the wireless communication unit.

In this case, the EPC function unit creates an IP packet forwarding table based on the shared node identification information of the relay wireless communication unit, refers to the forwarding table to control the IP packet forwarding, and also controls the wireless network. The system may be configured to include a transfer table update control unit that updates the contents of the transfer table according to the change when at least one of the number and connection order of wireless communication units included in the system is changed. can.

In the wireless communication unit of the present invention and the wireless network system using the same, relay wireless communication connectable with an upstream unit (upstream wireless base station section) that is another wireless communication unit on the upstream side via a radio bearer between the upstream units A section will be established. Further, the radio base station section can be connected to a downstream unit (downstream relay radio communication section), which is another radio communication unit on the downstream side, via an inter-downstream 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. In the present invention, the relay radio communication sections of a plurality of downstream units can be connected to the radio base station section of each radio communication unit via downstream unit-to-unit radio bearers that correspond one-to-one to those downstream units. be done. In other words, since multiple downstream units can be connected to one wireless communication unit, it is not limited to a configuration in which multiple wireless communication units are arranged in a linear chain, and multiple downstream units can be connected downstream from one wireless communication unit. It is also possible to adopt a star-shaped unit arrangement in which bearers are branched. Thereby, the connection topology between wireless communication units can be set more flexibly, and even a wide communication area can be efficiently covered.

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. 1 is a diagram schematically showing an example of a configuration of a wireless network system of the present invention. Conceptual diagram of a channel map. 5 is a flowchart showing the flow of channel setting processing for a UE. 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. Conceptual diagram of a transfer table. FIG. 3 is a diagram showing the flow of transfer table update processing. FIG. 3 is a communication flow diagram showing an IP packet transfer control sequence between UEs connected to the same wireless communication unit. FIG. 3 is a communication flow diagram showing an IP packet transfer control sequence between UEs connected to adjacent wireless communication units. FIG. 3 is a communication flow diagram showing an IP packet transfer control sequence between UEs connected to both ends of three connected wireless communication units. The communication flow diagram which shows the control sequence which transfers an IP packet to an external network via the router of the wireless communication unit located at the end of three connected wireless communication units. FIG. 3 is a communication flow diagram showing a control sequence of simple handover processing. The figure which shows the concept of UE list (connected node registration part). The figure which shows the flow of UE list update processing. FIG. 3 is a diagram illustrating an example of a process for attaching and connecting a new wireless communication unit to the first wireless communication unit of the wireless communication network system. The figure explaining an example of the process of attaching and connecting the wireless communication unit at the end of the wireless communication network system to the wireless communication unit. FIG. 3 is a diagram illustrating a reconnection process when an intermediate wireless communication unit leaves the wireless communication network system. FIG. 3 is a diagram illustrating a process of temporarily disconnecting an inter-unit radio bearer depending on the inter-unit distance and incorporating an approaching radio communication unit into the network by newly attaching it. Explanatory diagram following FIG. 28. FIG. 3 is a diagram illustrating a process of periodically disconnecting inter-unit radio bearers and incorporating them into the network by newly attaching approaching radio communication units. FIG. 7 is a diagram illustrating a modification example in which the timing of periodically disconnecting an inter-unit radio bearer is made different between a plurality of inter-unit radio bearers. The figure which shows an example of a CQI table. 12 is a flowchart showing the flow of connection adjustment processing for determining a final connection destination based on CQI when a plurality of wireless communication units compete as new connection destination candidates due to disconnection of an inter-unit radio bearer. 7 is a flowchart showing a process flow for temporarily disconnecting an inter-unit radio bearer according to an inter-unit distance based on unit position information. 10 is a flowchart showing the flow of processing for temporarily disconnecting an inter-unit radio bearer with reference to a disconnection scheduler. FIG. 3 is a diagram illustrating a process of incorporating a wireless communication unit whose number of connections to a wireless base station unit has not reached the upper limit into a network by newly attaching an approaching wireless communication unit. FIG. 1 is a diagram showing an example of a wireless network system in which a plurality of wireless communication units are connected in a tree configuration. FIG. 1 is a diagram showing an example of a wireless network system in which three wireless communication units are connected to one wireless communication unit. FIG. 1 is a diagram showing an example of a wireless network system configured using a wireless communication unit including a plurality of wireless base station sections.

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 consists of 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 device performs wireless communication with the UE (mobile terminal) 5 according to a communication protocol stack of a method defined by 3GPP (in this embodiment, LTE is used, but other methods such as WiMAX may be used). It is configured as.

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 WA (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 WA (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. Further, in the drawings attached to this specification, arrow lines indicating radio bearers are shown as broken lines, and wired bearers or electrical connection lines are shown as solid lines or dashed-dotted arrow lines.

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 for the radio base station section 4 (B) (upstream radio base station section) of the upstream radio communication unit 1 (B) (upstream unit). A relay wireless communication section 9 (A) connectable via a wireless bearer 55 (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). The inter-unit radio bearer 55 (downstream inter-unit radio bearer and upstream inter-unit radio bearer) has the same radio protocol stack as the terminal side radio bearer 57, and in this embodiment, both are constructed according to the LTE radio protocol stack. be done.

In both the wireless communication unit 1 (A) and the wireless communication unit 1 (B), the wireless base station sections 4 (A) and 4 (B) are configured so that the relay wireless communication sections of the plurality of downstream units communicate with each other. Connection is possible via radio bearers between downstream units that correspond one-to-one. In FIG. 2, the relay radio communication unit 9 (A) of the radio communication unit 1 (A) communicates with the radio base station unit 4 (B) of the radio communication unit 1 (B) using the inter-unit radio bearer 55 (A). Further, the relay wireless communication sections 9 (C) of the wireless communication unit 1 (C) are connected to each other by an inter-unit radio bearer 55 (C). In other words, the radio base station section is such that the relay radio communication sections of a plurality of downstream units can be connected to one radio base station section at the same time. Note that the wireless communication unit 1 (C) also includes a wireless base station section 4 (C) and an EPC function section 3 (C).

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. On the other hand, in a general LTE network, multiple wireless base stations are connected to a common core network, and when a UE moves between cells of adjacent wireless base stations, the wireless base stations are connected to each other on the control plane side. Handover control is performed via the X2 interface or the S1 interface on the core network side. However, in this embodiment, when a UE moves between cells 50(A) and 50(B) of radio communication units 1(A) and 1(B), both radio communication units 1(A) and 1( The wireless base station units 4(A) and 4(B) in B) are not connected by the X2 interface, and the EPC function units 3(A) and 3(B) corresponding to the core network are independent from each other. Therefore, the conventional handover control described above is not performed. Instead, a unique simple handover process is performed, the details of which will be described later.

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 that virtually implement functions are installed. Furthermore, the flash memory 305 also stores a transfer table 305e for performing IP packet transfer routing, a connected node registration section 305f, and a channel map 305g.

Furthermore, the flash memory 305 stores a network adjustment program 305h. The program 305h has the function of instructing the radio base station section 4 to temporarily and forcibly disconnect the downstream inter-unit radio bearer with the downstream unit (the specific process flow is as follows). , detailed in FIGS. 34 and 35).

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.

The relay wireless communication unit 9 is mainly composed of microcomputer hardware, and 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 stores communication firmware 905a including an LTE protocol stack for the relay wireless communication unit and an upstream unit connection switching control program 905b. 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 via 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 as the protocol stack for the UE (mobile terminal) described later. 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). In addition, the upstream unit connection switching control program 905b allows for higher quality if there are two or more wireless communication units as connection destination candidates when the relay wireless communication unit 9 attaches to the wireless base station unit of the upstream unit. A process of selecting a wireless communication unit that can be connected to as the upstream unit to be finally connected, or a process of selecting a switching candidate unit that is a wireless communication unit different from the upstream unit and capable of wireless connection with higher quality than the upstream unit. If it exists, it is responsible for the process of connecting and switching to the switching candidate unit as a new upstream unit.

Further, a router 8 that relays transmission and reception of IP packets between the EPC function unit 3 and an external network 60 such as the Internet is connected to the communication bus 30 (that is, a router 8 is connected to the EPC function unit 3 and an external network 60 such as the Internet). (A router 8 is provided between the two.)

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: channel Quality Indicator), and This is a physical channel used to notify the wireless base station section 4 of a request for transmission of uplink data (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. . As shown in Figure 32, CQI information represents the reception quality obtained through measurement using two parameters: coding rate and frequency utilization efficiency for each modulation method. The CQI index is reported from the UE5 to the eNodeB4 using the 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 of the present invention in which the wireless communication unit 1 having the above configuration is employed. 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 connected by inter-unit radio bearers 55(A), 55(B), and 55(C). Furthermore, the radio base station section 4 (C) of the radio communication unit 1 (C) has two radio communication units, specifically, the relay radio communication section 9 (B) of the radio communication unit 1 (B) is an inter-unit radio bearer. 55(B), and the relay wireless communication section 9(D) of the wireless communication unit 1(D) is connected by the inter-unit radio bearer 55(C). The inter-unit radio bearer 55 (B) and the inter-unit radio bearer 55 (C) are set to the same frequency channel (both CH2 in FIG. 11). On the other hand, from the perspective of the wireless communication unit 1 (B), the downstream inter-unit radio bearer 55 (A) and the upstream inter-unit radio bearer 55 (B) are set to different frequency channels (CH1 and CH2 in FIG. 11). .

For example, when a UE 5 (A) (mobile terminal) connected to one of the pair of wireless communication units 1 (A) and 1 (B) and a UE 5 (B) (mobile terminal) connected to the other, the pair of wireless communication units 1 (A), 1(B) and the inter-unit radio bearer 55(A) connecting the pair of wireless communication units 1(A) and 1(B), IP packets can be transmitted and received. 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.

Moreover, in FIG. 11, the number of wireless communication units connected by the inter-unit radio bearers 55(A) and 55(B) 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, it becomes possible to send and receive IP packets through wireless communication between the five devices.

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.

The terminal radio bearer 57 changes the number of frequency channels used within the same band as appropriate, depending on the number of UEs 5 connected to the radio base station section 4 and the congestion status of communication traffic caused by the amount of data to be transmitted. There is a need to. In addition, when a UE moves between cells with overlapping adjacent radio communication units, the frequency channel used by the terminal radio bearer 57 when connecting to each radio base station section between the cell before movement and the cell after movement is If they are the same, a problem of inter-cell interference will occur. Therefore, when the UE (mobile terminal) 5 moves to a cell on the downstream side, the radio base station section 4 of the radio communication unit 1 of the cell to which the UE (mobile terminal) 5 has moved is located, and the inter-unit (downstream) unit as seen from the radio base station section 4 Handover processing, which will be described later, is performed by switching to the set frequency channel ((downstream) inter-unit channel) of the radio bearer 55. On the other hand, when the UE (mobile terminal) 5 moves to an upstream cell, the (upstream) inter-unit radio Handover processing, which will be described later, is performed by switching to the set frequency channel ((upstream) inter-unit channel) of the bearer 55. That is, as the UE (mobile terminal) 5 moves between cells, the terminal radio bearer 57 is constructed by sequentially switching terminal-side channels. However, regarding the inter-unit radio bearer 55, the transmission of IP packets from each communication unit 1 to which a large number of UEs 5 are connected is aggregated, resulting in a very large amount of communication traffic, so the IP packet transmission process is made as smooth as possible. You are required to do so. At this time, if a situation arises in which the frequency channel settings of the inter-unit radio bearer 55 are frequently changed depending on the connection status of the UE 5 in each cell, IP packet transmission across multiple radio communication units 1 may be interrupted. When attempting to do so, problems such as communication breakdown in the inter-unit radio bearer 5 are likely to occur.

In the configuration of a wireless network system that connects a plurality of wireless communication units 1(A) to 1(D) as shown in FIG. If there is no change, the wireless base station section 4 to which the relay wireless communication section 9 of each wireless communication unit 1 is connected is fixed, and handover processing involving frequency channel switching is not required for the relay wireless communication section 9. Become. Therefore, by fixedly setting the inter-unit radio bearer 55 to an inter-unit channel that is one specific predetermined frequency channel, it is possible to effectively prevent communication interruptions caused by channel switching of the inter-unit radio bearer 55. , the stability of IP packet transmission when crossing multiple wireless communication units 1 can be greatly improved.

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. For example, if only one band is assigned to the entire wireless network system in FIG. The hardware of the radio base station section 4 and the relay radio communication section 9 including the construction of a radio bearer can be made into a single band specification, contributing to the simplification of the device configuration. Note that the terminal side channel may be switchably selected from the remaining frequency channels other than those set as the downstream inter-unit channel and the upstream inter-unit channel.

In this case, in a row of a plurality of wireless communication units 1 that are sequentially connected as shown in FIG. For units 1(A) to 1(D), it is desirable to set all the inter-unit channels of the inter-unit radio bearers 55(A) to 55(C) that connect these units to different frequency channels. On the other hand, when another wireless communication unit is connected upstream or downstream of wireless communication units 1(A) to 1(D) whose connection path lengths are within the limit distance L, It is also possible to set the inter-unit channel of the inter-unit radio bearer that connects the wireless communication units to the same frequency channel as any of the inter-unit channels allocated to the wireless communication units within the limit distance L. For example, in FIG. 11, when connecting a new wireless communication unit further upstream of wireless communication unit 1(A), the distance between the upstream units of wireless communication unit 1(A) that is farthest from the new wireless communication unit The same frequency channel CH1 as the channel can be set as the downstream inter-unit channel of the new wireless communication unit. In addition, inter-unit wireless communication between a plurality of wireless communication units 1(B) and 1(D) having the same wireless base station unit to connect to (the wireless base station to connect to is the wireless base station unit 4(C) in FIG. 11). Bearers 55(B) and 55(D) can be set to the same frequency channel (CH2 in FIG. 11), and channel control can be simplified.

Furthermore, in this embodiment, the band 28 defined by 3GPP is adopted as the same band. The 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.

Next, in the wireless network system of the present invention, inter-unit radio bearers that are adjacent in the upstream/downstream positional relationship from a certain radio communication unit as shown in FIG. 11, for example, the inter-unit radio bearers 55(A) and 55( As a specific method for making inter-unit channel settings different from each other in B), for example, each wireless communication unit 1(A) to 1( D) can be achieved by sharing channel information between units.

In addition, if the upper limit number of wireless communication units that participate in the wireless network system is determined, depending on the combination of node addresses assigned to individual wireless communication units 1(A) to 1(D) in FIG. Therefore, it is effective to uniformly define the types of inter-unit channels to be allocated in the form of a channel map, and to incorporate this channel map into the EPC function section 3 of each wireless communication unit, in order to further simplify the process. It is. Each EPC function unit 3 does not have to share channel setting information with the EPC function unit 3 of other wireless communication units, but by referring to the built-in channel map, the inter-unit channels of adjacent inter-unit radio bearers can be different. It is possible to set it so that. In this case, the EPC function section 1 has a channel map storage section that stores a channel map indicating the correspondence between a frequency channel group that can be selected as a downstream inter-unit channel and a node address of a downstream relay wireless communication section to be connected. Upon receiving an attach request from a downstream relay wireless communication unit, the node address of the downstream relay wireless communication unit is acquired, and the frequency channel corresponding to the acquired node address is specified on the channel map. The selected frequency channel is set as the downstream inter-unit channel.

FIG. 12 shows an example of the channel map 305g. In the channel map 305g, the number of wireless communication units 1 participating in system construction is four, and node addresses MID01 to MID04 are assigned to each of them. Then, according to the combination of these node addresses, channel numbers of inter-unit channels set between corresponding wireless communication units are determined so as not to cause duplication. This channel map 305g is updated at any time as the number of wireless communication units 1 increases or decreases and the arrangement changes.

FIG. 13 is a flowchart showing the flow of channel setting processing by the EPC function unit 3 using the channel map 305g. At B101, the channel number Ch#M of the downstream inter-unit channel is obtained from the node address of the downstream wireless communication unit by referring to the channel map 305g. In B102, the channel number Ch#B of the upstream inter-unit channel (this channel number Ch#B may be plural) is acquired from the upstream wireless communication unit. At B103, UE channel numbers Ch#U1, Ch#U2, etc. are selected from the remaining channel numbers other than Ch#M/Ch#B. Then, in B104, the radio base station unit and the UE are notified of the usable channel numbers (Ch#U1, Ch#U2, etc.). This notification is performed in the attach sequence of the radio base station unit and the UE.

The flow of the attach sequence between the relay wireless communication unit 9 and the UE 5 will be described below using FIGS. 14 and 15. FIG. 14 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.

MME2 searches channel map 305g (FIG. 12) for a wireless communication channel corresponding to the IP address of the requesting unit in TS5. Then, at TS6, a radio bearer setup request (attach acceptance) is notified to the radio base station section 4 along with the setup channel number. 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 (touch 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. 15 shows the attach sequence of UE5 (mobile terminal). In TS11, an attach request is issued from UE5 to MME2 via 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.

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.

In the LTE system, in order to flexibly change the transmission amount of broadcast information such as the set channel number mentioned above depending on the operation and environment, there are two types of broadcast information resources: fixed broadcast information resources using PBCH and variable usage using PDSCH. Wireless resources are used in combination. The reason why the fixed resource PBCH is used here is that the broadcast information is determined as the first information that the UE5 (relay radio communication unit 9) acquires, and the UE5 (relay radio communication unit 9) uses the radio base station unit ( This is because the eNodeB) 4 needs to be able to receive the notification without receiving it. The UE5 first receives the PBCH, which is a fixed resource, obtains the minimum information for receiving the PDSCH from the PBCH, and reads broadcast information sent on the PDSCH based on that information. Since the PDSCH is a variable resource that can be allocated in RB units, the amount of broadcast information transmitted on the PDSCH is variable. This makes it possible to change the amount of resources used for broadcast information, making it possible to allocate radio resources according to the amount of broadcast information, which varies depending on network operation and environment.

Of the broadcast information transmitted by this PBCH, the above-mentioned MIB is transmitted at the beginning of the radio frame (that is, subframe number = 0), and the time resources and frequency resources are always fixed. Assigned. The transmission information usually includes, for example, information for receiving other broadcast information (for example, SIB (System Information Block)) through PDSCH, and a radio frame number (SFN: System Frame Number). However, in this embodiment, the radio base station section 4 uses this MIB to distribute channel information of the terminal radio bearer or the inter-unit radio bearer to the UE 5 (relay radio communication section 9). The size of the MIB is fixed at 24 bits, of which 10 bits are a reserved area, so it is possible, for example, to incorporate the setting channel information of the radio bearer using this reserved area.

Next, as shown in FIG. 11, each EPC function section 3 of the two or more wireless communication units 1(A) to 1(D) connected by the inter-unit radio bearer 55 connects the individual wireless communication units 1(A) to 1(D) to each other. The node addresses (node identification information) of UEs 5 (A) to 5 (D) (mobile terminals) connected to the radio base station section 4 of 1 (D), and the inter-unit radio bearers 55 (A) to 55 (C). can be transferred to other wireless communication units via the As a result, between the wireless communication units 1(A) to 1(D) of the node address of UE5(A) to UE5(D) that are connected between two or more wireless communication units 1(A) to 1(D) It becomes possible to share the information. Then, the EPC function unit 3 creates an IP packet forwarding table based on the shared node address (node identification information), and performs IP packet forwarding control by referring to the forwarding table.

FIG. 16 shows an example of a transfer table. The forwarding table lists the node addresses (UEAD11, 12..., UEAD21, 22...) of connected UEs in each wireless communication unit (MAD01 to MAD04 indicate their node addresses). The currently connected node registration unit 305f registers the address of the wireless communication unit that is the final destination of the received packet, and the address of the wireless communication unit that is the next destination of the received packet (so-called next routing table 305ert stored in association with each other (hopping). In the wireless network system of this embodiment, the next hopping information indicates that the wireless communication unit to which the UE, which is the final packet transmission destination, is connected performs next hopping to its own node with respect to the wireless communication unit adjacent to its own lower side. The lower-level wireless communication unit that receives this broadcasts the same notification to the lower-level wireless communication units, so that the next hopping information for each wireless communication unit can be transmitted to the wireless communication unit that sent the packet. It will be transmitted sequentially until it reaches. Each wireless communication unit writes the broadcasted next hopping information in the routing table 305ert, and thereafter, when a packet to the same destination is transmitted, by referring to this routing table 305ert, the packet to the next wireless communication unit is Transfer is executed smoothly (so-called dynamic routing method). In this embodiment, the routing table 305ert shares and stores not only the next hopping information but also the addresses of wireless communication units on intermediate routes, but this may be omitted.

FIG. 17 shows the flow of the transfer table update process performed by each EPC function unit 3 (corresponding to the function of the transfer table update control unit). When the process is started in A201, it is checked in A202 whether the arrangement (order and number) of wireless communication units has changed. Specifically, it is checked whether the node address of the upstream unit or the downstream unit has changed due to the connection change described below. If it has changed, the process advances to A203, and the wireless communication to which the packet is sent is determined on the routing table 305ert. The node address of the next hopping wireless communication unit is changed for each node address of the unit. On the other hand, if there is no change, skip A203. At A204, the IP address of the UE connected to the local node is acquired. In A205, the contents of the connected node registration section 305f are updated with the acquired IP address. In A206, it is determined whether or not to end the process. If not, the process waits for a certain period of time in A207, then returns to A202, and repeats the following process.

FIG. 18 shows the flow of the IP packet transmission process between the UEs 5 (UE(I) and UE(II)) connected to the same wireless communication unit 1. U1 and U2 are the attach sequences already explained with reference to FIG. 15, and a terminal radio bearer is constructed. At U3, the IP packet is sent from the UE (I) to the wireless base station section 4 as an uplink packet. The wireless base station section 4 transfers this to the EPC function section 3. The EPC function unit 3 refers to the connected node registration unit 305f in FIG. 16 and determines whether the IP address of any UE connected to the wireless communication unit to which it belongs is recorded in the header of the received IP packet. Check whether it matches the destination address. In the case of FIG. 18, this corresponds to the IP address of UE (II), and in D1, the IP packet is transferred back to the subordinate wireless base station section 4 as a downlink packet. The radio base station unit 4 receives this and transfers it to the UE (II), and the process is completed.

FIG. 19 shows the IP packet transmission process between UE 5 (A) connected to wireless communication unit 1 (A) and UE 5 (B) connected to adjacent wireless communication unit 1 (A) in FIG. 11. It shows the flow. The processing from U1 to U3 is the same as in FIG. In U3, the EPC function unit 3 of the wireless communication unit 1(A) refers to the connected node registration unit 305f, and determines whether the destination address of the received IP packet is any of the connected nodes to the wireless communication unit 1(A) to which it belongs. It is confirmed that the next hop is the upstream wireless communication unit 1 (B) by referring to the routing table 305ert. Then, in U4, the IP packet is transferred to the upstream wireless communication unit 1 (B) by the inter-unit radio bearer 55 (A). The wireless communication unit 1 (B) receives this IP packet, similarly refers to the connected node registration unit 305f, and confirms that the IP address of the UE 5 (B) matches the destination IP address. Then, in D2, the IP packet is transferred to the subordinate wireless base station section 4 as a downlink packet. The radio base station unit 4 receives this and transfers it to the UE 5 (B), and the process is completed.

For example, a UE that is a source of an IP packet is connected to an intermediate one of a group of connected wireless communication units, and a UE that is a destination is a UE that is connected to a wireless communication unit downstream of the wireless communication unit. If so, the EPC function unit 3 in the UE refers to the connected node registration unit 305f, and determines whether the destination address of the received IP packet is the IP address of any UE currently connected to the wireless communication unit to which the UE belongs. Also, by referring to the routing table 305ert, it is confirmed that the next hopping is the downstream wireless communication unit. Then, the IP packet is transferred as a downlink packet to the radio base station section 4, and further transferred to the radio communication unit to which the destination UE is connected using a downstream inter-unit radio bearer.

FIG. 20 shows IP packets between UE 5 (A) connected to wireless communication unit 1 (A) and UE 5 (C) connected to wireless communication unit 1 (C) two places ahead in FIG. 11. This shows the flow of transmission processing. The processing from U1 to U4 is the same as in FIG. At U5, the EPC function unit 3 of the wireless communication unit 1 (B) refers to the connected node registration unit 305f, and determines whether the destination address recorded in the header of the received IP packet is the wireless communication unit 1 (B) to which it belongs. ), and U5 transfers the IP packet to the upstream wireless communication unit 1 (C) via the inter-unit radio bearer 55 (B). The wireless communication unit 1 (C) receives this IP packet, similarly refers to the connected node registration unit 305f, and confirms that the IP address of the UE 5 (C) matches the destination IP address. Then, in D3, the IP packet is transferred to the subordinate wireless base station section 4 as a downlink packet. The radio base station unit 4 receives this and transfers it to the UE 5 (C), and the process is completed.

FIG. 21 shows processing when an IP packet from UE 5 (A) connected to wireless communication unit 1 (A) has a destination address outside the wireless network system. The processing from U1 to U5 is the same as in FIG. 20. At U5, the EPC function unit 3 of the wireless communication unit 1 (C) refers to the connected node registration unit 305f, and determines whether the destination address recorded in the header of the received IP packet is the wireless communication unit 1 (C) to which it belongs. ), and the IP packet is transferred to the router 8 at U6. That is, when the destination node of the transferred IP packet indicates a node that is not included in the connected node registration section 305f, the EPC function section 3 of the wireless communication unit 1 (C) equipped with the router 8 The IP packet is transferred to the external network 60 via the router 8.

Each of the wireless communication units 1(A) to 1(D) in FIG. 11 has a built-in router 8, and can be connected to an external network 60 (eg, global public network (Internet)) via, for example, a satellite communication line 61. . It can be seen that with this configuration, the transfer processing of IP packets whose destination is a network outside the wireless network system of the present invention can be realized using a simple algorithm.

Note that for the IP packet transfer control processing in each wireless communication unit, a method using a simpler connected node registration unit may be used instead of the transfer table shown in FIG. 16. FIG. 23 shows an example of this, in which only the node identification information of the UE 5 currently connected to the wireless communication unit 1 in which the currently connected node registration section 305f' is provided is stored as a list. The node identification information is the IP address (UEIP01, UEIP02,...) of the connected UE, but is not limited to this as long as it is information that can identify the UE5 as a connected node, for example, the SIM (subscriber It is also possible to use the ID of the card (=terminal subscriber information of UE5: SIMID01, SIMID02, . . . ) and the MAC address of the device (MAD01, MAD02, . . . ).

That is, in FIG. 11, the EPC function section 3 of each radio communication unit 1(A) to 1(D) has a terminal radio bearer assigned to the radio base station section 4 within the cell (communication area) of the radio base station section 4. Regarding the plurality of UE5(A) to 5(D) (mobile terminals) connected via 57(A) to 57(D), the node identification information of the connected UE5(A) to 5(D) is A connected node registration unit 305f' for registration is provided. The EPC function section 3 compares the destination node (destination address) of the IP packet transferred from the wireless base station section 4 with the registered contents of the connected node registration section 305f', and confirms that the destination node is registered as a connected node. When indicating a UE (mobile terminal) corresponding to any of the node identification information registered in the section 305f', the IP packet is forwarded to the UE in a looped manner at the radio base station section 4.

On the other hand, if the destination node indicates a node that is not registered in the connected node registration section 305f', the IP packet is transferred to both the relay wireless communication section 9 and the wireless base station section 4. In other words, in this method, the EPC function unit 3 that has received an IP packet indicating an external destination can determine whether the destination node is on the upstream side or the downstream side based only on the contents of the connected node registration unit 305f'. I can't tell. Therefore, this problem is solved by transferring IP packets indicating external destinations to both the upstream and downstream sides without particularly limiting the transmission direction.

The method using the connected node registration unit 305f' has the advantage that, unlike the method using the forwarding table of FIG. 16, there is no need for communication processing to cooperate with other wireless communication units for dynamic routing. In other words, each wireless communication unit only needs to concentrate on the process of grasping the state of the UE to which it is connected. FIG. 24 shows the flow of the process. When the process starts at A101, it is checked at A102 whether there is an attach request from a new UE. If there is an attach request, the process proceeds to A103 and new node identification information of the corresponding UE is registered, while if there is no attach request, A103 is skipped. Next, in A104, it is checked whether there is any UE that has been disconnected. If there is a UE that has been disconnected, the process proceeds to A105 and the node identification information of the corresponding UE is deleted, whereas if there is no UE that has been disconnected, A105 is skipped.

For example, when focusing on the wireless communication unit 1 (B) in FIG. 11, the relay wireless communication unit 9 transmits the IP packet transferred from the EPC function unit 3 to the upstream The packet is transferred as an upstream packet to the wireless base station section 4 (upstream wireless base station section) of the wireless communication unit 1 (C). On the other hand, the radio base station section 4 of the radio communication unit 1 (B) transmits the IP packet transferred from the EPC function section 3 to the downstream radio communication unit 1 (A) via the downstream inter-unit radio bearer 55 (A). The packet is transferred to the wireless base station section 4 (downstream wireless base station section) as a downlink packet. By performing this process in each wireless communication unit 1(A) to 1(D), if the destination UE exists in the wireless network system, the destination of the IP packet to be transmitted is It can always be identified by either link or downlink. Of the uplink and downlink, on the side where there is no destination for the IP packet to be transmitted, the IP packet will reach the wireless communication unit at the end of the link (edge), but the wireless communication at the end If the unit cannot find the destination UE, the wireless communication unit may perform processing to invalidate the IP packet (eg, discard it).

Considering the case where the IP packet to be transmitted indicates a destination address outside the wireless network system, the wireless communication units 1(A) to 1(D) connected as shown in FIG. The units located at one end (referred to as wireless communication units 1(A) and 1(C) in FIG. 11) are defined as the units that execute the process of discarding the above IP packet, and the units located at the other end (referred to as wireless communication units 1(A) and 1(C) in FIG. A wireless communication unit 1 (C) in FIG. 11) is configured to be connectable to an external network 60 via a router 8. For example, an IP packet whose transmission source is a UE connected to the intermediate wireless communication unit 1 (B) and whose destination is specified as the external network 60 is transferred to the downlink side in this method by wireless communication. Since the packet is discarded by the communication unit 1 (A), only the IP packet transmitted to the uplink side survives and finally reaches the wireless communication unit 1 (C). In the wireless communication unit 1 (D), referring to FIG. 19, the destination address recorded in the header of the received IP packet is the IP address of any UE in the connected node registration unit 305f'. After confirming that they do not match, U6 transfers the IP packet to router 8. The IP packet is sent to the external network 60 via the router 8.

Next, the above-mentioned simple handover process will be explained.
As already explained using FIG. 2, in this embodiment, one wireless communication unit 1 (A) and the other wireless communication unit 1 (B) of the wireless communication unit pair are connected only by the inter-unit radio bearer 55. It is configured to be connected for communication. That is, the control interface that directly connects the wireless base station units 4 and 4 of the wireless communication unit pair 1(A) and 1(B) is omitted (that is, the configuration in which the conventional X2 interface is not provided). . Therefore, in FIG. 11, when the mobile terminal 5 (A) connected to the wireless communication unit 1 (A) moves into the communication cell 50B of the wireless communication unit 1 (B), normal handover processing using the X2 interface is performed. cannot be carried out. Therefore, in this embodiment, the following simple handover process is executed according to the sequence shown in FIG. That is, the UE 5 (A) executes the attach sequence shown in FIG. 15 in U1 and U2 with respect to the radio communication unit 1 (A), and establishes a terminal radio bearer with the radio communication unit 1 (A). This enables the UE 5 (A) to transmit and receive uplink packets (U3) and downlink packets (D1) to and from the wireless communication unit 1 (A).

Then, in S101, the UE5 (mobile terminal) detects disconnection of the terminal radio bearer connecting the radio base station section 4 of the radio communication unit 1 (A) and the UE5 (mobile terminal), and further in S102, the radio When the UE5 detects the communication unit 1(B), the UE5 makes a new attach request to the wireless communication unit 1(B) at U1'. Upon receiving this attach request, the radio communication unit 1 (B) establishes a new terminal radio bearer with the UE 5 based on the same process as U2. That is, based on a command from the EPC function section 3 of the wireless communication unit 1 (B), a terminal is installed between the wireless base station section 4 of the wireless communication unit 1 (B) and the UE 5 (A) (mobile terminal) after movement. radio bearer is reestablished. It can be seen that through the above processing, substantial handover processing can be realized as the UE 5 moves between cells, even in an environment where no inter-base station interface exists.

Hereinafter, a specific example in which the topology of wireless communication unit connections within the system is changed while the wireless network system of the present invention is being constructed will be described. Here, we will take as an example a case where the upper limit of the number of other wireless communication units (relay wireless communication units) that can be connected to the wireless base station unit of one wireless communication unit is set to two. In state A1 of FIG. 25, three wireless communication units 1 (B) to 1 (D) are connected by inter-unit radio bearers 5 (B) and 55 (C), and the first wireless communication unit 1 (B ) A new wireless communication unit 1 (A) is approaching. The eNodeB 4 of the wireless communication unit 1 (B) is in a state where other wireless communication units are not connected, and up to two new wireless communication units can be connected. Then, when the relay wireless communication unit (BTC) 9 enters the range of the eNodeB4 of the wireless communication unit 1 (B), the relay wireless communication unit (BTC) 9 sends an attach request to the eNodeB4 of the wireless communication unit 1 (B). Output toward the target. Below, the attach sequence already explained in FIG. 14 is executed, and as in state A2, an inter-unit radio bearer 55 (A) is established between the radio communication unit 1 (A) and the radio communication unit 1 (B). The wireless communication unit 1 (A) is then incorporated into the wireless network system. For example, in state A2, two new wireless communication units can be connected to wireless communication unit 1(A), and one new wireless communication unit can be connected to wireless communication units 1(B) to 1(D).

In state B1 of FIG. 26, three wireless communication units 1 (A) to 1 (C) are connected by inter-unit radio bearers 5 (A) to 55 (B), and the terminal wireless communication unit 1 (C ) A new wireless communication unit 1 (D) is approaching. One wireless communication unit 1 (B) is already connected to the wireless base station section 4 of the wireless communication unit 1 (C), and one new wireless communication unit can be connected thereto. When the relay wireless communication unit) 9 of the approaching wireless communication unit 1 (D) enters the range of the eNodeB 4 of the approaching wireless communication unit 1 (C), the relay wireless communication unit 1 (D) of the wireless communication unit 1 (D) The unit 9 transmits an attach request to the eNodeB 4 of the wireless communication unit 1 (C). In the following, the attach sequence already explained in FIG. (C) is constructed, and a wireless communication unit 1 (D) is incorporated into the wireless network system in a branched form.

For example, in FIG. 25, a newly added wireless communication unit connects to the wireless communication unit (symbol 1 (A) in FIG. 25) that constitutes the head of the already constructed wireless communication network system, that is, the edge of the network. An embodiment is shown. This method has the advantage that adding a wireless communication unit does not affect the connection order of wireless communication units in an existing network and is simple. However, since the attachment/connection is performed only when the wireless communication unit to be added approaches the wireless communication unit forming the edge, there is a drawback that flexibility for adding a new wireless communication unit is somewhat lacking. However, if the configuration allows multiple wireless communication units (relay wireless communication units) that can be attached and connected to the eNodeB4 as in the present invention, the wireless communication unit for which the bearer between downstream units has already been constructed In contrast, new wireless communication units can be attached until the number of downstream inter-unit bearers reaches the upper limit, and the connection topology can be extremely easily changed as the number of wireless communication units increases.

Note that, as shown in state B2 in FIG. 26, if a new wireless communication unit 1 (E) is approaching the end wireless communication unit 1 (C), the relay of the wireless communication unit 1 (C) When the wireless communication unit 9 enters the range of the approaching eNodeB4 of the wireless communication unit 1(D), the relay wireless communication unit 9 of the wireless communication unit 1(C) sends an attach request to the eNodeB4 of the wireless communication unit 1(D). By outputting to , an inter-unit radio bearer 55 (C) is constructed between them, and the wireless communication unit 1 (E) can be similarly incorporated into the wireless network system. In addition, as shown in FIG. 37, a plurality of wireless communication units 1 (B1) and 1 (B2) are branch-connected to the wireless communication unit 1 (A) which forms the starting point, and furthermore, on the downstream side thereof, a plurality of wireless communication units By sequentially repeating branching and connecting the communication units 1 (C11), 1 (C12) and 1 (C21), 1 (C22), it is possible to construct a wireless network system that follows a tree-like topology. Further, the upper limit of the number of wireless communication units (relay wireless communication units) that can be connected to one wireless base station unit is not limited to two, and for example, as shown in FIG. It is also possible to branch connect three (or more) wireless communication units 1 (B1) to 1 (B3) to the local area (eNodeB) 4.

On the other hand, when there is a switching candidate unit that is a wireless communication unit different from the upstream unit and can be wirelessly connected with higher quality than the upstream unit, the relay wireless communication unit selects the switching candidate unit as a new upstream unit. It can also be configured to switch connections. In FIG. 27, as the simplest case, as in state C1, a wireless communication unit 1 (C) located in the middle of a wireless communication network system consisting of a plurality of wireless communication units 1 (A) to 1 (D), The remaining radio when moving apart as in state C2 and leaving the network system as in state C3 (or when communication becomes impossible due to failure etc.; this can also be said to be a type of "leaving"). It shows the reconnection process of communication units 1(A), 1(B), and 1(D).

When the wireless communication unit 1 (C) leaves as described above, the quality of communication between the upstream unit (wireless communication unit 1 (D) in FIG. 27) and the wireless communication unit 1 (C) deteriorates. The connection of the inter-unit radio bearer 55(C) is disconnected. As a result, the wireless network system creates two network clusters CR1 and CR2, each of which has new edges as the two wireless communication units 1 (B) and 1 (D) that were connected to the wireless communication unit 1 (C) that left. Decompose into. Further, the wireless communication unit 1 (D) that is once isolated due to the disconnection becomes a switching candidate unit when viewed from the remaining wireless communication unit 1 (B) closest to it. In this case, as in state C3, when the wireless communication unit 1 (B) forming the edge of one network cluster CR1 makes an attach request to the wireless communication unit 1 (D) forming the edge of the other network cluster CR2, As in state C4, a new inter-unit radio bearer 55 (B') is established between radio communication unit 1 (B) and radio communication unit 1 (D), and the two network clusters CR1 and CR2 are reconnected. Complete.

Although FIG. 27 shows a simple case in which the only switching candidate unit resulting from the departure of wireless communication unit 1 (C) is wireless communication unit 1 (B), in reality, the remaining wireless communication unit 1 Due to the movement of (A), 1(B), and 1(D), a plurality of switching candidate units may occur, for example, as seen from the wireless communication unit forming the edge of either network cluster CR1 or CR2. Additionally, when another wireless communication unit outside the network approaches an intermediate wireless communication unit in the wireless communication network system, two or more of the wireless communication units located at the approach point become switching candidate units. There is also.

To change the connection of the wireless base station section to which the relay wireless communication section connects to the wireless base station section of another wireless communication unit, first disconnect the already established inter-unit radio bearer, and then In some cases, it may be necessary to re-establish a new inter-unit radio bearer between the radio base station section of the radio communication unit. Specifically, when another wireless communication unit outside the network approaches a wireless communication unit for which the number of connections of downstream units has reached the upper limit (2 in this embodiment), this inter-unit radio bearer is disconnected. If this can be forcibly executed from the upstream wireless communication unit according to the instructions from the EPC function unit depending on the situation, the connection topology between wireless communication units can be optimized by reconfiguring the inter-unit radio bearer. can be easily achieved. Specifically, the EPC function unit instructs the radio base station unit to temporarily and forcibly disconnect the downstream inter-unit radio bearer with the downstream unit (FIG. 3: Function of the network adjustment program 305h), and Upon receiving the instruction, the base station section performs control to disconnect the radio bearer between downstream units. In this case, as the upstream unit-to-unit radio bearer is disconnected, the upstream unit connection switching control unit connects the old upstream unit, which is the wireless communication unit that was connected as the upstream unit by the upstream unit-to-unit radio bearer, and the switching candidate unit. The configuration is such that a communication quality evaluation is performed for each of the wireless communication units and a wireless communication unit to be connected as a new upstream unit is determined based on the results of the communication quality evaluation (function of the upstream unit connection switching control program 905b).

An example is shown in FIGS. 28 and 29. In state D1 of FIG. 28, three wireless communication units 1(A) to 1(C) are connected by inter-unit radio bearers 5(A) and 55(B), and wireless communication units 1(B) and 1 A new wireless communication unit 1 (D) is approaching towards the middle of (C). In this situation, for example, the downstream inter-unit radio bearer forced disconnection instruction section of the wireless communication unit 1 (C) to which two downstream units 1 (B) and 1 (E), which are already connected to the upper limit number, indicates that the The downstream unit distance information that reflects the distances dc1 and dc2 from the downstream units 1(B) and 1(E) is acquired (downstream unit distance information acquisition section), and the wireless communication unit 1(D) becomes the switching candidate unit. The switching candidate unit distance information reflecting the distance d1 from the switching candidate unit is acquired (switching candidate unit distance information acquisition unit). In state D1, d1>dc1, dc2.

Then, as in state D2, the distance d1 to the switching candidate unit reflected in the acquired switching candidate unit distance information is different from the distance d1 to the downstream unit reflected in the acquired downstream unit distance information (for example, downstream unit 1 (B)), the EPC function section 3 of the wireless communication unit 1 (C) temporarily transfers the downstream inter-unit radio bearer (55 (B)) to the wireless base station section 4. and issue an instruction to forcibly disconnect. As a result, as in state D3, when the switching candidate unit (1 (D)) approaches so that it is closer than the already connected downstream unit (1 (C)), the distance determination described above allows the downstream unit-to-downstream unit radio bearer to be is forcibly disconnected, and as shown in state D4 in FIG. 29, the inter-unit radio bearer 55 (B') is reconfigured so that a new connection with the closer switching candidate unit (1 (D)) is created, and the inter-unit radio Bearer communication quality and throughput can be significantly improved.

The acquisition method of the downstream unit distance information and the switching candidate unit distance information can be selected from various forms, but for example, the simplest method is to acquire the current position of the wireless communication unit from the wireless communication unit. An acquisition unit is provided, and the downstream unit distance information acquisition unit and the switching candidate unit distance information acquisition unit acquire the current positions of the downstream unit and the switching candidate unit, and determine the distance to the downstream unit based on the information on the current positions. and a method of calculating the distance to the switching candidate unit. In this embodiment, as shown in FIG. 3, the wireless base station section 4 of each wireless communication unit 1 is provided with a GPS 413 (connected to the bus 405) which serves as a current position acquisition section. The unit 1 (D) can acquire the position information of the downstream unit 1 (C) as GPS information via the downstream inter-unit radio bearer (55 (B)). Furthermore, the position information of the switching candidate unit (1(D)) for which no inter-unit radio bearer has been established is obtained by GPS via the external network 60 connected to the router 8 via the satellite communication line 61 in FIG. It can be obtained as information.

FIG. 34 shows an example of the flow of the downstream inter-unit radio bearer forced disconnection process in this case by the network adjustment program 305h described above. In FIG. 28 (state D1), it is the EPC function section 3 of the wireless communication unit 1 (D) that performs this process. The C200 acquires its own position information from the GPS 413 (FIG. 3). Note that this position information is uploaded to the external network 60 (FIG. 3) so that other wireless communication units can use it for distance calculation. In C201, it is determined whether the number of downstream units that have been attached and connected has reached the upper limit (for example, 2 in this embodiment). If the upper limit has been reached, the process advances to C202, and the position information of the connected downstream unit 1 (B) (FIG. 28) is acquired via the inter-unit radio bearer 55 (B), and the position information of the above-mentioned own position is acquired. The distance dc is calculated based on the information.

Then, in C203, position information of a nearby switching candidate unit (wireless communication unit 1 (D) in FIG. 23) is acquired via the external network 60 (FIG. 3). In C204, the distance to each switching candidate unit is calculated, and the closest one is identified as d1. Then, in C205, if d1<dc, the process proceeds to C206, and the inter-unit radio bearer 55(B) with the connected downstream unit 1(B) (FIG. 28) is temporarily disconnected (FIG. 28: Status D2). Furthermore, if d1<dc does not hold in C205, C206 is skipped. On the other hand, in C201, if the number of downstream units receiving attachment/connection has not reached the upper limit, a new inter-downstream unit bearer can be newly constructed, so forced disconnection processing is not necessary, and the process jumps to C207. If the processing is not completed at C207, the process returns to C201 and the following processing is repeated.

When the inter-unit radio bearer is disconnected as described above, as in state D2 of FIG. (FIG. 3: Upstream unit connection switching control section), as in state D3, the old upstream unit 1 (C), which is a wireless communication unit that was connected as an upstream unit by the upstream unit inter-unit radio bearer 55 (B), Communication quality evaluation is performed for each switching candidate unit 1 (D), and processing is performed to determine a wireless communication unit to be connected as a new upstream unit based on the result of the communication quality evaluation. This makes it possible to further improve the quality of communication with the wireless communication unit after reconnection and the throughput of communication between the wireless communication units.

In this embodiment, a CQI reference signal is received from each wireless communication unit 1(C) and 1(D), CQI information (FIG. 32) is generated using the CQI reference signal, and based on the content of the CQI information, The communication quality is evaluated using the following methods. As mentioned above, the CQI information measurement and generation processing function is essential for the resource block scheduling algorithm in the case of LTE terminals (UE and relay radio communication unit), and is also incorporated into the 3GPP protocol as a standard specification. This has the advantage of being reusable. However, in the LTE protocol, CQI is measured after the terminal attaches to the radio base station, and in order to apply the present invention, it is necessary to perform CQI measurement outside the standard protocol before attaching. It is necessary to devise ways to handle this.

FIG. 33 shows an example of the flow of upstream unit connection switching control processing. In FIG. 28 (state D3), it is the relay wireless communication section 9 of the wireless communication unit 1 (B) that constituted the old downstream unit that performs this process. The wireless base station sections 4 of the wireless communication units 1 (C) and 1 (D) that are connection candidates output broadcast information for accepting the attachment of the UE 5 or the relay wireless communication section 9, respectively, according to the LTE protocol. In this embodiment, as a process outside the standard protocol, a reference signal for CQI measurement is transmitted following this broadcast information. This reference signal uses subcarriers of predetermined frequencies in specific symbols (for example, symbols "0" and "4") in each slot on the time axis in the resource block matrix of FIG. It has been inserted. Therefore, if the symbol number in the slot for acquiring the reference signal and the frequency subcarrier identification information are incorporated into the broadcast information, the relay wireless communication section 9 of the wireless communication unit 1 (B) can use this information. can be read to perform reception setting processing for reference signals for CQI measurement.

Returning to FIG. 33, in C102, it is checked whether the CQI reference signal is being received. If it has been received, the process advances to C103, and it is determined whether or not CQI reference signals are being received from multiple nodes. If received, the process proceeds to C104, and CQI measurement is performed for each CQI reference signal. Then, the process proceeds to C105, and as in state D4 in FIG. 29, the wireless communication unit with the best communication quality indicated by the measured CQI among the plurality of units (1(C), 1(D)), for example, in FIG. , for example, by requesting to attach to the wireless communication unit 1 (D) that is closest to the wireless communication unit 1 (B) and has the best coding rate and frequency usage efficiency reflected in the CQI information (see FIG. 32). , an inter-unit radio bearer 55 (B') is constructed between the radio communication unit 1 (D) and the radio communication unit 1 (D). On the other hand, in C103, if the CQI reference signal is not received from multiple nodes, that is, if it is received only from one node (wireless communication unit), the process proceeds to C106, and the CQI reference signal is sent to the unit regardless of the CQI measurement result. Make an attach request. If the process does not end at C107, the process returns to C101 and the following process is repeated.

In state D5 of FIG. 29, the wireless communication unit 1 (D) uses a similar algorithm to attach to the wireless communication unit 1 (C) closest to itself, and an inter-unit radio bearer 55 (C') is constructed. Reconnection is complete.

Note that, as shown in state G1 in FIG. 36, wireless communication units 1 (B) and 1 (C), which are the approach destinations of wireless communication unit 1 (D), are both connected when the number of downstream units connected is less than the upper limit number. If so, as shown in state G2, wireless communication unit 1 (D) receives CQI reference signals from both wireless communication units 1 (B) and 1 (C). Then, as shown in state G3, by requesting the wireless communication unit 1 (C) with the best communication quality indicated by the CQI measured based on this, an attach request is made to the wireless communication unit 1 (D). This is a simple sequence in which an inter-unit radio bearer 55 (C') is constructed.

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, the contents of the downstream inter-unit radio bearer forced disconnection process are not limited to those described above, and for example, as shown in states E1 and E2 in FIG. can be configured to output periodically at predetermined time intervals. The radio base station section disconnects the downstream inter-unit radio bearer periodically (for example, once every hour to once a year, preferably once every three hours to every three months, etc.) to reduce the impact on communication quality. The flow of processing after the downstream inter-unit radio bearer is disconnected is similar to that already described. In addition, in FIG. 30, all the downstream inter-unit radio bearers (55(A), 55(B)) are disconnected at the same time, but as shown in FIG. 31, the downstream inter-unit radio bearers are disconnected. It is also possible to shift the period for each wireless communication unit. In FIG. 31, state F0 indicates a state in which no downstream inter-unit radio bearer is disconnected, and states F1 to F3 indicate states in which any downstream inter-unit radio bearer is disconnected. In states F1 to F3, the downstream inter-unit radio bearers to be disconnected are different from each other.

FIG. 35 shows an example of the processing flow in that case, and in C301, for example, timekeeping information of a disconnection scheduler incorporated in the network adjustment program 305h is referred to. In C302, it is checked whether a predetermined cutting time has arrived. If it has arrived, the process advances to C303, where processing is performed to temporarily disconnect the connection state with the connected wireless communication unit. Furthermore, if the cutting time has not arrived at C302, C303 is skipped. If the process does not end at C304, the process returns to C301 and the following process is repeated.

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 wireless communication units 1'(A) to 1'(C) shown in FIG. It is set up. In FIG. 39, the wireless communication unit 1'(A) is an upstream unit, and the wireless communication unit 1'(B) is a downstream unit, and the inter-unit radio bearer 55 is connected to the wireless base station section 4(X). (X), and the wireless communication unit 1' (C) is connected to the wireless base station section 4 (Y) by establishing an inter-unit radio bearer 55 (Y). In this case, the inter-unit radio bearer 55 (X) and the inter-unit radio bearer 55 (Y) can be set to different frequency channels. Thereby, the communication capacity (throughput) between the inter-unit radio bearer 55 (X) and the inter-unit radio bearer 55 (Y) can be significantly expanded.

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 305e Transfer table 305ert Routing table 305f Connected node registration unit 305g Channel map 306 Bus 21 Secondary battery Module 22 Power supply circuit section 23 Portable housings 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 section 50(A), 50(B) Communication area 55 Inter-unit radio bearer 57 Terminal radio bearer

Claims (19)

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;
The radio base station section of the upstream unit (hereinafter referred to as the upstream radio base station section) is connected to the EPC function section by wire, and is a first separate wireless communication unit, and the upstream unit radio bearer (hereinafter referred to as the upstream unit inter-unit radio bearer) A relay wireless communication unit that can be connected via a radio bearer (referred to as a radio bearer),
The radio base station unit communicates with a relay radio communication unit of a downstream unit (hereinafter referred to as a downstream relay radio communication unit), which is a second separate radio communication unit, and a downstream inter-unit radio bearer (hereinafter referred to as a downstream inter-unit radio bearer). ) can be connected via
The EPC function section transmits a downstream inter-unit radio bearer setting request to the radio base station section, while the radio base station section receives the downstream inter-unit radio bearer setting request and transmits the downstream inter-unit radio bearer setting request together with the downstream relay radio communication section. It constructs a bearer,
The EPC function unit transmits a terminal radio bearer setting request to the radio base station unit, and the radio base station unit constructs the terminal radio bearer together with the mobile terminal in response to the terminal radio bearer setting request. can be,
The relay radio communication unit receives an upstream unit radio bearer setting request issued by an EPC function unit (hereinafter referred to as upstream EPC function unit) of the upstream unit, and upon receiving the upstream unit radio bearer setting request, the relay radio communication unit The upstream unit-to-unit radio bearer is constructed together with the radio base station section , and further,
The radio base station section is a radio communication unit characterized in that the relay radio communication sections of the plurality of downstream units can be connected to the downstream units via inter-downstream unit radio bearers that correspond one-to-one to the downstream units. When the relay radio communication unit detects a candidate for an upstream unit to be a new connection destination in a state where the upstream unit is not connected, the relay radio communication unit constructs the upstream unit-to-unit radio bearer for the radio base station unit of the candidate upstream unit. an upstream inter-unit radio bearer construction control unit that performs control to receive the upstream inter-unit radio bearer setting request from the upstream unit candidate and construct the upstream inter-unit radio bearer by transmitting an attach request for the upstream unit candidate; The wireless communication unit according to claim 1. 3. The radio communication unit according to claim 1, wherein the radio base station section is configured such that relay radio communication sections of a plurality of downstream units can be connected to one radio base station section at the same time. 4. The radio communication unit according to claim 3, wherein the relay radio communication sections of the plurality of downstream units are simultaneously connected to the one radio base station section by the downstream inter-unit radio bearer set on the same frequency channel. When the radio base station section receives an attach request from a candidate for a newly connected downstream unit in a state where the number of connections of the downstream unit is one or less, the radio base station section notifies the EPC function section of the attach request. , comprising a downstream inter-unit radio bearer construction control section that receives the terminal radio bearer setting request from the EPC functional section and controls construction of the downstream inter-unit radio bearer with the downstream unit candidate. The wireless communication unit according to claim 3 or 4. 3. The wireless communication unit according to claim 1, wherein a plurality of said wireless base station sections are connected to one said EPC function section, each of which is connectable to a relay wireless communication section of said downstream unit. 6. A relay radio communication section of the downstream unit is connected to a plurality of radio base station sections connected to one EPC function section by the downstream inter-unit radio bearer set on a different frequency channel. The wireless communication unit described. When the wireless base station section receives an attach request from a candidate for a downstream unit to be newly connected while the downstream unit is not connected, the radio base station section notifies the EPC function section of the attach request, and Claim 7, further comprising a downstream inter-unit radio bearer construction control section that receives the terminal radio bearer setting request from the functional section and performs control to construct the downstream inter-unit radio bearer with the downstream unit candidate. The wireless communication unit described. When there is a switching candidate unit that is a wireless communication unit different from the upstream unit and can be wirelessly connected with higher quality than the upstream unit, the relay wireless communication unit selects the switching candidate unit as a new upstream unit. The wireless communication unit according to any one of claims 1 to 8, further comprising an upstream unit connection switching control section that switches connection to the unit. The wireless communication unit according to claim 9, wherein the upstream unit connection switching control section switches the connection to the switching candidate unit when the connection with the upstream unit is disconnected due to a decrease in communication quality with the upstream unit. . The EPC function section includes a downstream inter-unit radio bearer forced disconnection instruction section that instructs the radio base station section to temporarily and forcibly disconnect the downstream inter-unit radio bearer with the downstream unit, The radio base station section includes a downstream inter-unit radio bearer disconnection control section that receives the instruction and performs disconnection control of the downstream inter-unit radio bearer,
When the upstream unit-to-unit radio bearer is disconnected, the upstream unit connection switching control unit is configured to connect the old upstream unit, which is a wireless communication unit that was connected as the upstream unit by the upstream unit-to-unit radio bearer, and the switching candidate. The wireless communication unit according to claim 9 or 10, wherein the wireless communication unit evaluates communication quality with respect to each unit, and determines the wireless communication unit to be connected as a new upstream unit based on the result of the communication quality evaluation. The upstream unit connection switching control section receives a CQI reference signal from each of the wireless communication units, generates CQI information using the CQI reference signal, and performs the communication quality evaluation based on the content of the CQI information. 12. The wireless communication unit according to item 11. When the number of connections of the downstream units to the wireless communication unit to which the EPC function unit belongs has reached a predetermined upper limit, the EPC function unit instructs the downstream unit-to-downstream unit radio bearer forced disconnection instruction unit to Claim 11 or claim 11, wherein an instruction is given to temporarily and forcibly disconnect the inter-unit radio bearer, while allowing additional connections of the downstream units when the number of connections of the downstream units is less than the upper limit number. 13. The wireless communication unit according to item 12. The EPC function unit is configured to provide information about the relay radio communication units of the plurality of mobile terminals and other radio communication units that are connected to the radio base station via the terminal radio bearer within the communication area of the radio base station unit. , a connected node registration unit that registers node identification information of the connected mobile terminals, and compares the destination node of the IP packet transferred from the wireless base station unit with the registered contents of the connected node registration unit. , when the destination node indicates a mobile terminal corresponding to any of the node identification information registered in the connected node registration unit, the IP packet is returned to the mobile terminal at the wireless base station unit. On the other hand, if the destination node indicates a node that is not registered in the connected node registration unit, the IP packet is transferred from at least one of the relay wireless communication unit and the wireless base station unit to the wireless communication unit. The wireless communication unit according to any one of claims 1 to 13, which controls transfer to an external destination. 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 unit that is connected by wire to the wireless base station and functions as an upper network control unit for the wireless base station; The radio base station includes a radio base station section of a certain upstream unit (hereinafter referred to as an upstream radio base station section) and a relay radio communication section connectable via an upstream inter-unit radio bearer (hereinafter referred to as an upstream inter-unit radio bearer); The base station section connects a relay radio communication section of a downstream unit (hereinafter referred to as a downstream relay radio communication section), which is a second separate radio communication unit, and a downstream inter-unit radio bearer (hereinafter referred to as a downstream inter-unit radio bearer). The EPC function section transmits a downstream inter-unit radio bearer setting request to the radio base station section, while the radio base station section receives the downstream inter-unit radio bearer setting request and performs the downstream relay radio communication. The EPC functional unit is configured to construct the downstream inter-unit radio bearer with the EPC function unit, and the EPC function unit transmits a terminal radio bearer setting request to the radio base station unit, while the radio base station unit receives the terminal radio bearer setting request. The relay radio communication unit constructs the terminal radio bearer together with the mobile terminal, and the relay radio communication unit receives an inter-upstream unit radio bearer setting request issued by the EPC function unit of the upstream unit (hereinafter referred to as upstream EPC function unit). and constructs the upstream inter-unit radio bearer together with the upstream radio base station in response to the upstream inter-unit radio bearer setting request; The communication unit is connectable to the downstream units via a downstream unit radio bearer that corresponds one-to-one , and comprises a plurality of the radio base station units to constitute a radio communication unit, and a plurality of the radio communication units arranged to form a wireless communication unit group,
The radio communication unit group is connected by the inter-unit radio bearer in a positional relationship in which base station cells of a pair of radio communication units constituted by the radio communication units adjacent to each other partially overlap, and
A mobile terminal connected to one of the pair of wireless communication units and a mobile terminal connected to the other pair of wireless communication units transmit and receive IP packets via the pair of wireless communication units and the inter-unit radio bearer connecting the pair of wireless communication units. A wireless network system characterized by performing the following. 16. The radio network system according to claim 15, wherein in at least one of the radio communication units, a plurality of the downstream units are connected to the radio base station section by different inter-unit radio bearers. Each of the EPC function units of the plurality of radio communication units connected by the inter-unit radio bearer is connected to the plurality of radio communication units connected to the radio base station via the terminal radio bearer within the communication area of the radio base station unit. The relay wireless communication unit of the mobile terminal and other wireless communication unit includes a connected node registration unit that registers node identification information of the mobile terminal that is connected to the mobile terminal, and the relay wireless communication unit of the mobile terminal and the other wireless communication unit includes a connected node registration unit that registers node identification information of the connected mobile terminal, The destination node of is compared with the registered contents of the connected node registration section, and if the destination node indicates a mobile terminal corresponding to any of the node identification information registered in the connected node registration section. , the IP packet is forwarded to the mobile terminal in a looped manner at the wireless base station section, while if the destination node indicates a node that is not registered in the connected node registration section, the IP packet is transferred to the mobile terminal by the relay. The wireless network system according to claim 15 or 16, wherein control is performed to transfer the information from at least one of the wireless communication unit and the wireless base station unit to a transmission destination outside the wireless communication unit. The EPC function unit creates a forwarding table for the IP packet based on the shared node identification information of the relay wireless communication unit, and controls the forwarding of the IP packet by referring to the forwarding table. A transfer table update control unit that updates the contents of the transfer table according to the change when at least one of the number and connection order of the wireless communication units included in the wireless network system is changed. The wireless network system according to claim 17. The transfer table includes a connected node registration section in which the addresses of connected mobile terminals are registered in a list in each wireless communication unit, and a wireless communication unit to which the received packet is ultimately transferred. and a routing table in which the address of the wireless communication unit to which the received packet is next transferred are stored in association with each other, and the EPC function section stores the number and connection order of the wireless communication units. 19. The wireless network system according to claim 18, further comprising a routing table changing unit that changes the contents of the routing table according to the change when at least one of the above is changed.

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