JP7277300B2 - Wireless communication unit and wireless network system using it - Google Patents

Description

TECHNICAL FIELD The present invention relates to a wireless communication unit for performing wireless network communication with a mobile terminal, which can easily realize cooperative operation between a plurality of units, and can be suitably used for covering a wide area. The present invention relates to a wireless communication unit and a wireless network system using it.

For example, in a wireless communication network of a high-speed communication standard based on 3GPP specifications (for example, LTE (Long Term Evolution) or WiMAX (Worldwide Interoperability for Microwave Access), an EPC (Evolved Packet Core) that accommodates the wireless communication access network is placed within the area. The wireless base station to which the mobile terminal connects receives IP packet transmission/reception control via the EPC.On the other hand, with the spread of mobile terminals such as mobile phones, smart phones and tablet PCs, maritime I want to use mobile terminals even in areas where EPC and wireless base stations are not developed as infrastructure (hereinafter referred to as "wireless areas") such as depopulated areas, areas where communication functions have been lost due to disasters, etc. There is a growing demand for

In order to meet such a demand, Patent Document 1, for example, proposes a composite wireless communication unit in which a wireless base station and an EPC function unit are integrated. By installing such a wireless communication unit in the wireless unserviced area as described above, a small but communicable area is constructed by the wireless base station section included in the unit, and the EPC function section in the unit performs communication control. In this manner, wireless communication can be performed among 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 conceivable to place multiple wireless communication units in an area where wireless communication is not available. , there is a drawback. In addition, when the number of connected mobile terminals increases, or when large-capacity data such as video data is transmitted and received, problems such as congestion tend to occur when communication traffic in the area becomes excessive.

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 to each wireless communication unit for transfer processing. Specifically, FIG. 6 of Patent Document 5 discloses a configuration in which a satellite device is used as a cooperation route between wireless communication units for offloading communication with a mobile terminal.

JP 2016-12841 JP 2018-137661 A JP 2018-137662 A JP 2018-137663 A JP 2018-137664 A JP 2018-137665 A JP 2018-137666 A

Patent Documents 2 to 7 illustrate how a plurality of wireless communication units are interconnected (for example, FIG. 1 of Patent Document 2). There is no specific disclosure in the literature as to what entity constitutes this connection, except for the offloading configuration via satellite equipment discussed above. However, assuming that the wireless communication units are connected by wire, if you try to disperse the wireless communication units in a correspondingly wide communication area in an area where wireless communication is not available, the communication cable that connects the devices will be required. gets very long. As a result, the signal quality and communication capacity are degraded, and a repeater device is required to prevent this. Furthermore, in applications where wireless communication units are mounted on moving bodies such as trains, automobiles, and ships, it is physically impossible to connect each wireless communication unit with a cable. Also, if it is assumed that the wireless communication units are wirelessly connected to each other, the connection topology of the wireless communication units is not taken into consideration 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 a plurality of wireless communication units with a simple structure. An object of the present invention is to provide a configurable wireless communication unit and a wireless network system using it.

In order to solve the above problems, a wireless communication unit according to the present invention is configured to be mountable on a mobile body and is a wireless communication unit for performing wireless network communication with a mobile terminal, the mobile terminal comprising: A radio base station unit connectable via a terminal radio bearer, an EPC (Evolved Packet Core) function unit connected by wire to the radio base station unit and functioning as an upper network control unit for the radio base station unit, and a wire connection to the EPC function unit While being connected, via the radio base station section of the upstream unit (hereinafter referred to as the upstream radio base station section), which is a first separate radio communication unit, and the upstream inter-unit radio bearer (hereinafter referred to as the upstream inter-unit radio bearer) and a plurality of relay wireless communication units that can be connected to each other via the wireless base station unit. A connection is possible via a wireless bearer between units (hereinafter referred to as a wireless bearer between downstream units), and the EPC function unit transmits a wireless bearer setting request between downstream units to the wireless base station unit, while the wireless base station unit performs wireless communication between downstream units. In response to a bearer setting request, a wireless bearer between downstream units is constructed together with the downstream relay wireless communication unit. A terminal radio bearer is constructed together with a mobile terminal in response to a bearer setting request. It is characterized by receiving a bearer setting request, and individually constructing an upstream unit-to-unit radio bearer together with an upstream radio base station section in response to the upstream unit-to-unit radio bearer setting request.

Further, the radio network system of the present invention is a radio communication unit configured to be mountable on a mobile object and for performing radio 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 unit, an EPC (Evolved Packet Core) functional unit wired to the wireless base station unit and functioning as an upper network control unit for the wireless base station unit, and a wired connection to the EPC functional unit, a first A plurality of relays that can be connected via a wireless base station section of an upstream unit (hereinafter referred to as an upstream wireless base station section), which is another wireless communication unit of the upstream unit, and an upstream inter-unit wireless bearer (hereinafter referred to as an upstream inter-unit wireless bearer) a wireless communication unit, and the wireless base station unit includes a relay wireless communication unit (hereinafter referred to as a downstream relay wireless communication unit) of a downstream unit that is a second separate wireless communication unit (hereinafter referred to as a downstream relay wireless communication unit) and a downstream inter-unit wireless bearer (hereinafter referred to as The EPC function unit transmits a request for setting a wireless bearer between downstream units to the wireless base station unit, while the wireless base station unit receives the request for setting a wireless bearer between downstream units, and transmits the wireless bearer setting request between downstream units to the downstream unit. It constructs a radio bearer between downstream units together with the relay radio communication section. While the EPC function section transmits a terminal radio bearer setting request to the radio base station section, the radio base station section receives the terminal radio bearer setting request and moves. A terminal radio bearer is constructed together with a terminal, and a plurality of relay radio communication units receive a radio bearer setting request between upstream units issued by an EPC function unit of an upstream unit (hereinafter referred to as an upstream EPC function unit), comprising a radio communication unit group in which a plurality of radio communication units individually configured to independently establish a radio bearer between upstream units together with an upstream radio base station section in response to the radio bearer setting request between upstream units; The communication unit group is connected by an inter-unit radio bearer in a positional relationship in which the base station cells of the wireless communication unit pairs adjacent to each other partially overlap, and is connected to the mobile terminal connected to one of the wireless communication unit pairs and the other. The mobile terminal transmits and receives IP packets via a wireless communication unit pair and an inter-unit wireless bearer connecting the wireless communication unit pair.

In the radio communication unit (and the radio network system) of the present invention, the plurality of relay radio communication sections can be configured so as to be capable of individually constructing radio bearers between upstream units with different upstream radio base station sections. In this case, it is possible to individually establish upstream inter-unit radio bearers between a plurality of relay radio communication units and different upstream radio base station units using mutually different frequency channels.

In the wireless communication unit (and wireless network system) of the present invention, in its subordinate concept, a plurality of relay wireless communication units detects a candidate for an upstream unit to be a new connection destination while the upstream unit is not connected. Then, by transmitting an attach request for constructing a radio bearer between upstream units to the radio base station section of the candidate for the upstream unit, receiving a radio bearer setting request between the upstream units from the candidate for the upstream unit, and performing communication between the upstream units It is possible to configure each unit to include a radio bearer construction control section between upstream units that performs control for constructing a radio bearer.

Also, the radio base station section can be configured so that the relay radio communication sections of a plurality of downstream units can be simultaneously connected via individual downstream unit-to-unit radio bearers. In this case, individual inter-downstream-unit radio bearers constructed between the radio base station section and the relay radio communication sections of a plurality of downstream units can be constructed using the same frequency channel. Furthermore, when the radio base station receives an attach request from a candidate for a downstream unit to be newly connected in a state in which the number of connected downstream units is one or less, the radio base station notifies the EPC function unit of the attach request, It can be configured to include a downstream unit radio bearer construction control section that receives a terminal radio bearer setting request from the EPC function section and performs control for constructing a downstream unit radio bearer with a downstream unit candidate. .

On the other hand, the wireless communication unit of the present invention can also be configured such that a plurality of wireless base station sections are connected to one EPC control section, and each relay wireless communication section of a downstream unit can be connected. In this case, the relay wireless communication units of the downstream units can be configured to be connected to the multiple wireless base station units connected to one EPC control unit by wireless bearers between downstream units set on mutually different frequency channels. .

When there is a switching candidate unit which is a wireless communication unit different from the upstream unit and which 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 have 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 as the connection with the upstream unit is cut due to deterioration of the communication quality with the upstream unit.

The EPC function unit includes a downstream inter-unit radio bearer forced disconnection instruction unit that instructs the radio base station unit to temporarily and forcibly disconnect the radio bearer between downstream units with the downstream unit. a downstream unit connection switching control unit configured to perform disconnection control of a wireless bearer between downstream units in response to an instruction; Perform communication quality evaluation on each of the old upstream unit, which is a wireless communication unit connected as an upstream unit by a bearer, and the switching candidate unit, and wireless communication to be connected as a new upstream unit based on the result of the communication quality evaluation. Can be configured to determine the unit. In this case, more specifically, the upstream unit connection switching control section receives a CQI (Channel Quality Indicator) reference signal from each wireless communication unit, generates CQI information using the CQI reference signal, It can be configured to perform communication quality evaluation based on the content. Further, the EPC function unit instructs the inter-downstream unit wireless bearer forced disconnection instruction unit to It can be configured to issue an instruction to temporarily and forcibly disconnect the radio bearer, while permitting additional connections of the downstream unit if the number of connections of the downstream unit is less than the upper limit.

Further, the downstream unit wireless bearer forced disconnection instruction unit includes a downstream unit distance information acquisition unit that acquires downstream unit distance information that reflects the distance to the currently connected downstream unit, and a switching candidate unit 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 downstream unit that is reflected in the acquired downstream unit distance information. can be configured to issue an instruction to temporarily and forcibly disconnect the wireless bearer between downstream units when the distance dc becomes smaller than the distance dc.

A current position obtaining section for obtaining the current position of the wireless communication unit is provided, and the downstream unit distance information obtaining section and the switching candidate unit distance information obtaining section obtain the respective current positions from the downstream unit and the switching candidate unit, and The distance to the upstream/downstream unit and the distance to the switching candidate unit can be calculated based on the current position information. Further, the downstream inter-unit radio bearer forced disconnection instruction section can be configured to periodically output an instruction to disconnect the downstream inter-unit radio bearer at predetermined time intervals.

In addition, the EPC function unit is configured to connect relay radio communication units of a plurality of mobile terminals and other radio communication units connected to the radio base station via terminal radio bearers within the communication area of the radio base station unit. A connected terminal registration section for registering terminal identification information of mobile terminals inside the network, and the mobile terminal that is the destination of the IP packet transferred from the radio base station section is compared with the registered contents of the connected terminal registration section and transmitted. When the destination mobile terminal indicates a mobile terminal corresponding to any of the terminal identification information registered in the connected terminal registration unit, the IP packet is transferred to the mobile terminal in a form that is looped back at the radio base station unit. On the other hand, when the destination mobile terminal indicates a mobile terminal that is not registered in the connected terminal registration section, the IP packet is sent from at least one of the relay radio communication section and the radio base station section to the destination outside the radio communication unit. It can be configured to control transfer.

In this case, the EPC function unit creates an IP packet forwarding table based on the shared terminal identification information of the relay wireless communication unit, refers to the forwarding table, and performs IP packet forwarding control. When at least one of the number of wireless communication units included in the system and the order of connection is changed, it may be configured to have a transfer table update control section that updates the content of the transfer table according to the content of the change. can.

In the wireless network system of the present invention, in at least one of the wireless communication units, a plurality of relay wireless communication units can be configured to be connected to wireless base station units of different upstream units by inter-unit wireless bearers. . When the radio base station section of the radio communication unit is configured to allow the relay radio communication sections of a plurality of downstream units to be simultaneously connected via individual inter-downstream unit radio bearers, at least In one configuration, a plurality of different downstream units may be connected to the radio base station section by inter-unit radio bearers. In this case, a plurality of wireless communication units can be connected in a mesh pattern by inter-unit wireless bearers.

Each EPC function part of a plurality of radio communication units connected by inter-unit radio bearers is connected to a plurality of mobile terminals and others connected to the radio base station via terminal radio bearers within the communication area of the radio base station part. The relay radio communication unit of the radio communication unit of the above is provided with a connected terminal registration unit that registers terminal identification information of the mobile terminals that are currently connected, and specifies the mobile terminal that is the destination of the IP packet transferred from the radio base station unit. When the destination mobile terminal indicates a mobile terminal corresponding to any of the terminal identification information registered in the connected terminal registration unit, the IP packet is sent to the corresponding mobile terminal. While transferring to the mobile terminal in the form of looping back at the radio base station section, when the destination mobile terminal indicates a mobile terminal that is not registered in the connected terminal registration section, the IP packet is relayed by the radio communication section and the radio 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 terminal identification information of the relay wireless communication unit, refers to the forwarding table, and performs IP packet forwarding control. When at least one of the number of wireless communication units included in the system and the order of connection is changed, it can be configured to have a transfer table update control section that updates the content of the transfer table according to the content of the change.

In addition, the transfer table includes a connected terminal registration section in which addresses of connected mobile terminals are registered in a list form, and a wireless communication unit to be the final transfer destination of the received packet. and a routing table that stores the address of the wireless communication unit to be the next transfer destination of the received packet in association with each other. It can be configured to include a routing table change unit that changes the content of the routing table according to the content of the change when any one of them is changed. In this case, the wireless communication unit to be the final transfer destination of the packet is set as the destination node, and the plurality of wireless communication units leading to the destination node are set as the relay nodes, and the next transfer destination when the packet is sent to the destination node. With each wireless communication unit as the next hopping node, each wireless communication unit updates and sets the next hopping node address corresponding to the destination node in the routing table so that the route is optimized in the direction of decreasing the number of relay nodes. It can be configured as having a table updating unit.

In the radio communication unit of the present invention and the radio network system using the same, relay radio communication that can be connected to an upstream unit (upstream radio base station section), which is another radio communication unit on the upstream side, via a radio bearer between upstream units. Department is provided. Also, the radio base station section is connectable to a downstream unit (downstream relay radio communication section), which is another radio communication unit on the downstream side, via a downstream inter-unit radio bearer. As a result, a plurality of wireless communication units can be connected by inter-unit wireless bearers, and a wireless network system covering a wider area can be easily constructed by the plurality of wireless communication units. In the present invention, one wireless communication unit is provided with a plurality of relay wireless communication units, and these relay wireless communication units receive a wireless bearer setting request between upstream units issued by the EPC function unit of the upstream unit (upstream EPC function unit). are received, and upon receiving the upstream unit radio bearer setting request, the upstream unit radio bearer is individually constructed together with the upstream radio base station section. It is also possible to adopt a unit arrangement in which a plurality of downstream unit-to-unit radio bearers are branched upstream from one radio communication unit. This makes it possible to more flexibly set the connection topology between the wireless communication units and efficiently cover a wide communication area.

FIG. 2 is a schematic diagram showing the concept of a wireless communication unit pair, which is a constituent unit of the wireless network system of the present invention; FIG. 2 is a block diagram showing an outline of an electrical configuration of the wireless communication unit pair in FIG. 1; FIG. 2 is a block diagram showing an example of the electrical configuration of the wireless communication unit of the present invention; FIG. 2 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 protocol stack of a 3GPP control plane; FIG. 2 is a diagram conceptually showing a protocol stack of a 3GPP user plane; FIG. 2 is a diagram conceptually showing 3GPP downlink channel mapping; FIG. 4 is a diagram conceptually showing uplink channel mapping. FIG. 2 is a conceptual diagram showing the relationship between frequency band channels and resource blocks; 1 is a diagram schematically showing an example of the configuration of a wireless network system according to the present invention; FIG. Conceptual diagram of a channel map. 4 is a flowchart showing the flow of channel setting processing for a UE; 4 is a communication flow diagram showing an attach sequence of a relay wireless communication unit of a wireless communication unit to another wireless communication unit on the upstream side; FIG. FIG. 3 is a communication flow diagram showing an attach sequence of a UE (mobile terminal) to a radio communication unit; A conceptual diagram of a forwarding table. FIG. 10 is a flow chart showing the flow of content update processing of a connected node registration unit accompanying an adjacent node change; FIG. 4 is a flowchart showing the flow of processing for updating the contents of a routing table; FIG. 4 is a communication flow diagram showing an IP packet transfer control sequence between UEs connected to the same radio communication unit; 4 is a communication flow diagram showing an IP packet transfer control sequence between UEs respectively connected to adjacent wireless communication units; FIG. FIG. 4 is a communication flow diagram showing an IP packet transfer control sequence between UEs each connected to an opposite end of three in-line wireless communication units. FIG. 4 is a communication flow diagram showing a control sequence of simple handover processing; FIG. 4 is a diagram for explaining a first example of a process for attaching/connecting a new wireless communication unit to the wireless communication network system; The figure similarly explaining a 2nd example. FIG. 11 is a diagram similarly explaining a third example; FIG. 4 is a diagram for explaining a reconnection process when an intermediate wireless communication unit is disconnected in a wireless communication network system; FIG. 4 is a diagram for explaining a process of temporarily disconnecting an inter-unit radio bearer according to the inter-unit distance and incorporating the approaching radio communication unit into the network by newly attaching it. FIG. 27 is an explanatory diagram following FIG. 27 ; FIG. 29 is an explanatory diagram following FIG. 28 ; FIG. 2 is a schematic diagram showing a configuration example of a wireless communication system in which a plurality of wireless communication units are connected in a mesh pattern by inter-unit wireless bearers; FIG. 4 is an explanatory diagram showing the concept of the shortest route when there are multiple routes from a source node to a destination node; The figure which shows an example of a CQI table. 4 is a flowchart showing the flow of processing for temporarily disconnecting an inter-unit radio bearer according to the inter-unit distance; 10 is a flow chart 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; Conceptual diagram of dynamic routing 1 is a diagram showing an example of a wireless network system configured using wireless communication units having a plurality of wireless base station units; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic diagram showing, as an embodiment, the concept of a wireless communication unit pair, which is a constituent unit of the wireless network system of the present invention. The wireless communication unit pair has wireless communication units 1(A) and 1(B) having the same configuration as one embodiment of the present invention (hereinafter also referred to as wireless communication unit pair 1(A) and 1(B)). , each performs wireless communication with a UE (mobile terminal) 5 in accordance with the communication protocol stack of the system defined by 3GPP (in this embodiment, LTE is used, but other systems such as WiMAX may be used). configured as a thing.

The wireless communication units 1(A) and 1(B) are installed on the large ships WS(A) and WS(B), which are mobile bodies, respectively, and are wirelessly connected by an inter-unit wireless 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 be connected. Small vessels FB (eg, fishing boats, tugboats, etc.) are operating around the large vessels WS (A), WA (B) (eg, fishing mother ships, tankers, etc.). The crew of the small vessel FB in (B) carries the UE5. These UEs 5 are wirelessly connected to the closest wireless communication units 1(A) and 1(B) by terminal wireless bearers 57, respectively. The UE 5 may be carried by crew members of the large vessels WS (A) and WA (B). Also, the wireless communication units 1(A) and 1(B) may be installed on a mobile object (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 the functional block configuration of the wireless communication units 1(A) and 1(B). The wireless communication units 1(A) and 1(B) electrically have the same configuration. In this specification, when a plurality of wireless communication units and their constituent elements are distinguished from each other, the same numbers are given to the corresponding constituent elements, followed by parenthesized capital letters. is shown. On the other hand, when each component is indicated without distinguishing between wireless communication units, parenthesized capital letters may be omitted. In the following, the description will be made mainly using the codes on the wireless communication unit 1(A) side, but the corresponding codes on the wireless communication unit 1(B) side will also be used when necessary.

A 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). and an EPC (Evolved Packet Core) function unit 3(A) that is wired to the radio base station unit 4(A) and functions as an upper network control unit for the radio base station unit 4(A). The EPC function section 3(A) also includes 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 plurality of relay wireless communication units 9 (A1) and 9 (A2) connectable via (wireless bearers between upstream units) (two in the present embodiment, but may be three or more) are connected by wire. there is On the other hand, the radio communication unit 1(B) is wired to a similar radio base station section 4(B) and the radio base station section 4(B), and functions as a higher network control section for the radio base station section 4(B). EPC function unit 3(B), and a plurality of relay wireless communication units 9(B1) and 9(B2) (two in this embodiment, but three or more) wired to EPC function unit 3(B). can also be used).

In both the wireless communication unit 1(A) and the wireless communication unit 1(B), the plurality of relay wireless communication units 9(A1), 9(A2) and the plurality of relay wireless communication units 9(B1), 9(B2) ) can be independently connected to the radio base station section of the radio communication unit via the inter-unit radio bearer if another radio communication unit is arranged upstream. Further, in both the wireless communication unit 1(A) and the wireless communication unit 1(B), the wireless base station units 4(A) and 4(B) are configured so that the downstream wireless communication unit (downstream relay wireless communication unit) A plurality (two in this embodiment, but may be three or more) can be simultaneously connected via a downstream inter-unit radio bearer (downstream inter-unit radio bearer).

In FIG. 2, the wireless communication unit 1 (A) is located downstream of the wireless communication unit 1 (B), and the relay wireless communication section 9 (A2) of the wireless communication unit 1 (A) is the inter-unit wireless bearer 55 ( A) is connected to the radio base station section 4 (B) of the radio communication unit 1 (B). When viewed from the radio communication unit 1(B), the radio communication unit 1(A) forms a downstream unit, the unit-to-unit radio bearer 55(A) corresponds to the downstream unit-to-unit bearer, and the radio base station section 4(A) corresponds to the downstream radio unit. Corresponds to the base station. Conversely, the wireless communication unit 1(B) is located upstream of the wireless communication unit 1(A), and the wireless base station section 4(B) of the wireless communication unit 1(B) is the inter-unit wireless bearer 55(A). ) to the relay wireless communication section 9 (A2) of the wireless communication unit 1 (A). When viewed from the radio communication unit 1(A), the radio communication unit 1(B) forms an upstream unit, the unit-to-unit radio bearer 55(A) corresponds to the upstream unit-to-unit bearer, and the radio base station section 4(B) corresponds to the upstream radio unit. Corresponds to the base station.

The wireless communication unit 1(A) and the wireless communication unit 1(B) are also connected to the wireless communication unit 1(C) having the same electrical configuration. Specifically, in the wireless communication unit 1(C), the relay wireless communication unit 9(C1) communicates with the wireless base station unit 4(A) of the wireless communication unit 1(A) via the inter-unit bearer 55(B1). The relay radio communication section 9 (C2) is independently connected to the radio base station section 4 (B) of the radio communication unit 1 (B) via the inter-unit bearer 55 (B2). The wireless communication unit 1(C) also includes a wireless base station section 4(C) and an EPC function section 3(C). When viewed from the wireless communication unit 1(C), the wireless communication unit 1(A) and the wireless communication unit 1(B) are both upstream units, and the inter-unit bearers 55(B1) and 55(B2) are between the upstream units. Applicable to bearers. The unit-to-unit radio bearers 55(A), 55(B1), 55(B2) are constructed according to the radio protocol stack of the same method as the terminal-side radio bearer 57, and in the present embodiment, all are constructed according to the LTE radio protocol stack. be.

As described above, a plurality of relay wireless communication units are capable of individually constructing upstream unit-to-unit wireless bearers between different upstream wireless base station units. Further, the radio base station section is configured such that the relay radio communication sections of a plurality of downstream units can be simultaneously connected via individual downstream unit-to-unit radio bearers. This makes it possible to more flexibly set the connection topology between the wireless communication units and efficiently cover a wide communication area. Also, regardless of whether the wireless communication unit is on the upstream side or the downstream side, a plurality of other wireless communication units and the three wireless communication units 1(A), 1(B), and 1(C) are three inter-unit wireless bearers. 55(A), 55(B1), and 55(B2) form a "mesh" of the network. For example, in a wireless network system including more wireless communication units, by connecting (attaching) two relay wireless communication units of each wireless communication unit to the wireless base station units of different wireless communication units, as shown in FIG. A plurality of wireless communication units 1 are connected in a mesh form by inter-unit wireless bearers 55 (the arrow indicates the direction of attachment, the starting point of the arrow corresponds to the relay wireless communication section, and the end point of the arrow corresponds to the wireless base station section). A network system can be constructed.

Next, in any of the wireless communication units 1(A), 1(B), 1(C) (hereinafter collectively referred to as wireless communication unit 1), the EPC function unit 3 functions as a gateway on the control plane side. An MME (Mobility Management Entity) 2, an S-GW (Serving Gateway) 6 serving as a user plane side gateway, an EPC function unit 3, and an upstream network element of the EPC function unit 3 (here, a router 8 (described later) and relay wireless communication unit 9) and has a P-GW (Packet Data Network) Gateway (P-GW) 7 that performs IP address management toward the upstream network element side (that is, the upstream unit side). A plurality of UEs 5 are wirelessly connected to the radio base station unit 4 via terminal radio bearers 57 . On the control plane side, the radio base station unit (eNodeB) 4 is connected to the MME 2 via the S1-MME interface. Also, on the user plane side, the radio base station unit 4 is connected to the S-GW 6 via the S1-U interface. Also, S-GW6 is connected to P-GW7 via an S5 interface. On the other hand, in a general LTE network, multiple radio base stations are connected to a common core network, and when a UE moves between adjacent radio base station cells, the control plane side connects the radio base stations. Handover control is performed via the X2 interface on the side of the core network or the S1 interface on the core network side. However, in this embodiment, for example, when the UE moves between the cells 50(A) and 50(B) of the radio communication units 1(A) and 1(B), both radio communication units 1(A) and 1(B) The radio 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 of each other. Therefore, the conventional handover control described above is not performed. Instead, a specific 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. As shown in FIG. The EPC function unit 3 is mainly composed of microcomputer hardware, and includes a CPU 301, a RAM 302 serving as a program execution area, and a mask ROM 303 (permanently storing firmware for microcomputer hardware peripheral control that does not require rewriting; hereinafter, etc.) and a bus 306 or the like that interconnects them. Also, a flash memory 305 is connected to the bus 306, and communication firmware 305a including an LTE protocol stack for EPC is used here. Programs of an MME entity 305b, an S-GW entity 305c and a P-GW entity 305d that virtually realize functions are installed. Further, the flash memory 305 also stores a transfer table 305e, a transfer table update program 305f, and a channel map 305g for performing IP packet transfer routing.

Furthermore, the flash memory 305 stores a network adjustment program 305h. The program 305h has a function of instructing the radio base station section 4 to temporarily and forcibly disconnect the downstream unit-to-unit radio bearer with the downstream unit (the specific processing flow is , FIG. 33 and FIG. 34).

The bus 306 is also connected to an upstream communication interface 304A and a downstream communication interface 304B. An input/output port for IP packets for the P-GW is secured in the upstream side communication interface 304A, and an input/output port for IP packets for the S-GW is secured in the downstream side 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 they may be configured by 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 interconnecting them, and the like. A flash memory 405 is connected to the bus 406, and communication firmware 405a including the LTE protocol stack for the wireless base station is stored therein. Also, the bus 406 is connected to a radio communication unit 412 and a communication interface 404 for radio connection with the UE by constructing a terminal radio bearer. The communication interface 404 is connected to the downstream side communication interface 304B of the EPC function unit 3 via the wired communication bus 31 .

In addition, a plurality of relay wireless communication units are provided, two sets of 9 (A1) and 9 (A2) in FIG. there is Therefore, the description will be made on the other hand (both relay wireless communication units will be collectively referred to as a relay wireless communication unit 9 hereinafter). The relay wireless communication unit 9 includes a CPU 901, a RAM 902 serving as a program execution area, a mask ROM 903, and a bus 906 interconnecting them. 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. Also connected to the bus 906 are a wireless communication unit 912 for wirelessly connecting with an upstream wireless base station unit by constructing an inter-unit wireless bearer, and a communication interface 904 . The communication interface 904 is connected to the upstream side 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 connection procedure of the relay radio communication unit 9 to the upstream radio base station unit is the same as the attach sequence, which is the connection procedure of the UE (mobile terminal). In addition, the upstream unit connection switching control program 905b, when the relay wireless communication unit 9 attaches to the wireless base station unit of the upstream unit, if there are two or more wireless communication units as candidates for the connection destination, the higher quality A process of selecting a wireless communication unit that can be connected as an upstream unit to be finally connected, or a switching candidate unit that is a wireless communication unit that is different from the upstream unit and that can be wirelessly connected with higher quality than the upstream unit. If it exists, it is responsible for the processing of switching connection to the switching candidate unit as a new upstream unit.

Also, the communication bus 30 is connected to 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 (that is, the EPC function unit 3 and the relay wireless communication unit 9 are connected). and a router 8 is provided between them).

Next, the wireless communication unit 1 includes a detachable secondary battery module 21 (for example, a lithium ion secondary battery module, a nickel hydrogen secondary battery module, etc.), a wireless base station section 4, an EPC function section 3, a router 8 and Each functional circuit block of the relay wireless communication unit 9 and a power supply circuit unit 22 that converts an input voltage from the secondary battery module 21 into a driving voltage for each functional circuit block and outputs the 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 drive power supply voltage from the secondary battery module 21, and can be used without problems even in installation locations (for example, on the sea) where external power supply voltages such as commercial alternating current cannot be used. be. The portable housing 23 has a box shape made of metal or reinforced resin, and in the example shown in FIG. A handle 24 is provided for.

When the output voltage of the secondary battery module 21 drops due to discharge, the secondary battery module 21 is removed from the portable housing 23 and mounted on a dedicated charger connected to, for example, a commercial AC power supply (not shown) or a private power generator. It is possible to charge by The power supply circuit unit 22 can also receive the commercial alternating current and the external power supply voltage such as a centralized power supply unit provided in a moving body, and can convert and output the drive power supply voltage. Furthermore, it is also possible to configure such that the secondary battery module 21 can be charged by the external power supply voltage. For example, when the power supply circuit unit 22 is receiving power from a commercial alternating current or the like and the power supply is interrupted due to a power failure, the operation of the wireless communication unit 1 can be continued by switching to power reception from the secondary battery module 21. It can also be configured as

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 comprised as the smart phone provided with the microcomputer 100 as a processing subject. The microcomputer 100 includes a CPU 101, a RAM 102 serving as a program execution area, a ROM 103, an input/output unit 104, and a bus 106 interconnecting them. A flash memory 105 is connected to the bus 106, and an OS (not shown) for building an operating environment for the UE 5, a terminal application 105b, and the like are installed therein.

A monitor 109 is connected to the input/output unit 104 via a graphic controller 1091 . A touch panel 110 that forms an input unit is superimposed on the monitor 109, and cooperates with various software operation units (such as buttons and icons: see FIGS. 13 to 17) displayed on the monitor 109 to control the operation of the UE 5. Various necessary information inputs are made. A touch panel 110 is connected to the input/output unit 104 via a touch panel controller 1101 . A camera 111 for capturing still images or moving images is connected to the input/output unit 104 . Furthermore, a wireless communication unit 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 of FIG.

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

6 and 7 show radio protocol stacks in the LTE system, with FIG. 6 showing a user plane protocol stack and FIG. 7 showing a control plane protocol stack. The wireless protocol stack is partitioned 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 via physical channels between the PHY layer of the UE 5 and the relay wireless communication unit 9 and the PHY layer of the wireless base station unit (eNodeB) 4 .
MAC layer: Performs data priority control, retransmission control processing by HARQ, random access procedure, and the like. 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 transport channels. 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: uses functions of the MAC layer and the PHY layer to transmit data to the RLC layer of the receiving side. Data and control signals are transmitted between the RLC layer of the UE 5 and the RLC layer of the radio base station unit 4 via logical channels.
- PDCP layer: Performs header compression/decompression and encryption/decryption of PDUs.
• RRC layer: defined only in the control plane that handles control signaling. A message (RRC message) for various settings is transmitted between the RRC layer of the UE 5 and the RRC layer of the radio base station unit 4 . The RRC layer controls the 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 UE 5 and the RRC of the radio base station unit 4, the UE 5 is in RRC connected mode, otherwise it is in RRC idle mode.

These 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. above the RRC layer. A GTP-U (GPRS (General Packet Radio Service) Tunneling Protocol for User Plane) layer is provided in the user data transmission interface between the radio base station unit 4 and the EPC function unit 3 side. The GTP-U layer is for identifying the connected UE 5 or the 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, the mapping relationship among logical channels (Downlink Logical Channels), transport channels (Downlink Transport Channels) and physical channels (Downlink Physical Channels) is shown. They will be described in order below.
- DTCH (Dedicated Traffic Channel) is a dedicated logical channel for the transmission of data. The DTCH is mapped to a 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 UE 5 and relay radio communication unit 9 have an RRC connection with radio base station unit 4 . DCCH is mapped to DLSCH.
• CCCH (Common Control Channel): a logical channel for transmission control information between the UE 5 and the relay radio communication unit 9 and the radio base station unit 4 . CCCH is used when UE 5 and relay radio communication unit 9 do not have an RRC connection with radio base station unit 4 . CCCH is mapped to DLSCH.

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

Also, 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, it shows the mapping relationship between logical channels (Downlink Logical Channels), transport channels (Downlink Transport Channels) and physical channels (Downlink Physical Channels). They will be described in order below.

CCCH (Common Control Channel): A logical channel used for transmitting control information between the UE 5 and the relay radio communication unit 9 and the EPC function unit 3, and the EPC function unit 3 and radio resources Used by UEs 5 that do not have a radio resource control (RRC) connection.
DCCH (Dedicated Control Channel): A one-to-one (point-to-point) two-way logical channel, individual control information between UE 5 and relay wireless communication unit 9 and EPC function unit 3 This is the channel used to send the A dedicated control channel DCCH is used by UEs 5 that have an RRC connection.
• DTCH (Dedicated Traffic Channel): A one-to-one bi-directional logical channel, dedicated to a particular UE or relay radio, used for the transfer of user information.

ULSCH (Uplink Shared Channel: HARQ), dynamic adaptive radio link control, and discontinuous transmission (DTX: Discontinuous Transmission) are supported transport channels.
RACH (Random Access Channel): transport channel in which limited control information is transmitted.

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

As shown in FIG. 9, in the uplink, mapping of transport channels and physical channels is performed as follows. The uplink shared channel ULSCH is mapped to the physical uplink shared channel PUSCH. A random access channel RACH is mapped to a physical random access channel PRACH. A physical uplink control channel PUCCH is used as a physical channel alone. Also, the common control channel CCCH, the dedicated control channel DCCH, and the 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 by OFDM (Orthogonal Frequency-Division Multiplexing) access (OFDMA). The OFDMA system is characterized as a two-dimensional multiplexed access system that combines frequency division multiplexing and time division multiplexing. Specifically, the orthogonal frequency axis and time axis subcarriers are divided and allocated to UE 5, and the orthogonal subcarriers on the frequency axis are divided so that the signal of each subcarrier is zero (0 points). . By dividing subcarriers and allocating them on the frequency axis, even if a subcarrier is affected by fading, it is possible to select another subcarrier that is not affected by fading. There is an advantage that subcarriers can be used and radio quality can be maintained.

In the OFDMA system, a resource block (hereinafter also referred to as RB) defined on a virtual plane defined by a frequency axis and a time axis is adopted as a radio resource. As shown in FIG. 10, RB is defined as a block in which the above plane is divided into a matrix of 180 kHz/0.5 msec. It contains one slot (7 symbols) of the frame. These RBs are assigned to the UE 5 and the relay wireless communication unit 9 as a set of two adjacent RBs (1 msec) on the time axis. On the other hand, also 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 by the following procedure in a 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 FIG. 32, the CQI information represents the reception quality obtained by measurement with two parameters, the coding rate and the frequency utilization efficiency, for each modulation scheme. is reported from UE5 to eNodeB4 using the CQI index.

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

FIG. 11 shows a configuration example of the wireless network system of the present invention when the wireless communication unit 1 having the above configuration is adopted. In the wireless network system, the wireless communication unit groups 1(A) to 1(D) are adjacent wireless communication unit pairs (1(A) and 1(B), 1(B) and 1(C), 1( B) and 1(D)) base station cells (50(A) and 50(B), 50(B) and 50(C), 50(B) and 50(D)) partially overlap each other. , are connected by inter-unit radio bearers 55(A), 55(B), 55(D). Also, the relay wireless communication section 9 (B1) of the wireless communication unit 1 (B) is connected to the wireless base station section 4 (D) of the wireless communication unit 1 (D) via the unit-to-unit wireless bearer 55 (D). 9 (B2) is independently and individually connected to the radio base station section 4 (C) of the radio communication unit 1 (C) by the inter-unit radio bearer 55 (B).

For example, the plurality of relay radio communication units 9 (B1) and 9 (B2) of the radio communication unit 1 (B) are different upstream radio base station units, ie, the radio base station unit 4 (D) and the radio base station unit 4 (C). ) by upstream unit radio bearers 55(D) and 55(B), which are constructed using different frequency channels CH5 and CH2. It is Also, the inter-unit radio bearer 55(A) is set to a frequency channel (CH1 in FIG. 11) different from any of these. Furthermore, when viewed from the wireless communication unit 1(B), the wireless bearer 55(A) between the downstream units and the wireless bearers 55(B) and 55(D) between the upstream units are different frequency channels (CH1, CH2 and CH5 in FIG. 11). ). On the other hand, for example, in the connection form shown in FIG. Radio bearers 55(A) and 55(B2) can be established using the same frequency channel.

For example, the UE 5 (A) (mobile terminal) connected to one of the wireless communication unit pairs 1 (A) and 1 (B) and the UE 5 (B) (mobile terminal) connected to the other are connected to the wireless communication unit pair 1. (A), 1(B) and the wireless communication unit pair 1(A), 1(B) can be transmitted and received via the unit-to-unit wireless bearer 55(A). The wireless communication unit groups 1(A) to 1(D) may be all mounted on a mobile body such as the aforementioned ship or vehicle, or only some of them may be mounted on a mobile body, The remainder may be fixedly installed in a building or the like.

In the wireless communication system of the 3GPP specifications, any one of a plurality of frequency bands defined by the 3GPP is assigned. The assigned frequency band differs depending on the communication system. 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 predetermined bandwidths, and the EPC function unit 3 selects predetermined frequency channels for the unit-to-unit radio bearer 55 and terminal radio bearer 57 in FIG. It will be constructed by That is, each of the downstream inter-unit channel, the upstream inter-unit channel, and the terminal-side channel is set as a frequency channel belonging to one of a plurality of bands defined by 3GPP.

In this embodiment, the EPC function unit 3 fixedly sets the set frequency channel of the (downstream) unit-to-unit radio bearer 55 to the (downstream) unit-to-unit channel, which is a predetermined specific frequency channel. Also, 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) unit-to-unit channel. That is, the EPC function unit 3 sets the same frequency channel for the relay radio communication unit 9 of the radio communication unit 1 on the downstream side and the mobile terminal 5 for the radio base station unit 4 directly below.

The terminal radio bearer 57 appropriately changes the number of frequency channels used within the same band according to the number of UEs 5 connected to the radio base station unit 4 and the state of communication traffic congestion caused by the amount of data to be transmitted. There is a need to. Further, when the UE moves between cells having overlapping adjacent radio communication units, the frequency channel used by the terminal radio bearer 57 when connecting to each radio base station section in the cell before movement and in the cell after movement is Being identical creates inter-cell interference problems. Therefore, when the UE (mobile terminal) 5 moves to a cell on the downstream side, the distance between the (downstream) units seen from the radio base station section 4 to the radio base station section 4 of the radio communication unit 1 in the destination cell is Handover processing, which will be described later, is performed by switching to the set frequency channel ((downstream) unit-to-unit channel) of the radio bearer 55 . On the other hand, when the UE (mobile terminal) 5 moves to an upstream cell, the radio base station section 4 of the radio communication unit 1 of the destination cell receives (upstream) unit-to-unit radio from the radio base station section 4. Handover processing, which will be described later, is performed by switching to the set frequency channel ((upstream) unit-to-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 the terminal-side channel. However, regarding the unit-to-unit radio bearer 55, transmission of IP packets from each communication unit 1 to which a large number of UEs 5 are connected is aggregated, and the amount of communication traffic becomes extremely large. It is required to do At this time, if a situation arises in which the frequency channel setting of the inter-unit radio bearer 55 is frequently changed according to the connection status of the UE 5 in each cell, IP packet transmission across a plurality of radio communication units 1 is performed. When trying to do so, problems such as interruption of communication in the inter-unit radio bearer 5 tend to occur.

In the configuration of a wireless network system connecting a plurality of wireless communication units 1(A) to 1(D) as shown in FIG. If there is no change, the radio base station section 4 to which the relay radio communication section 9 of each radio communication unit 1 is to be connected is fixed, and handover processing involving frequency channel switching for the relay radio communication section 9 is unnecessary. Become. Therefore, by fixedly setting the inter-unit radio bearer 55 to an inter-unit channel, which is a predetermined specific frequency channel, it is possible to effectively prevent communication interruptions and the like caused by channel switching of the inter-unit radio bearer 55. , the stability of IP packet transmission across multiple wireless communication units 1 can be greatly improved.

When the (upstream) unit-to-unit radio bearer is constructed, each EPC function unit 3 of the radio communication units 1(A) to 1(D) sets the downstream unit-to-unit channel to the upstream unit-to-unit radio bearer. On the other hand, 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 unit 3 of the wireless communication unit 1(B) is set for the upstream unit wireless bearers 55(B) and 55(D). Channels between upstream units are set to CH2 and CH5, respectively. On the other hand, the EPC function unit 3 of the wireless communication unit 1(A) has a wireless bearer 55(A) between upstream units viewed from the wireless communication unit 1(A) (a wireless bearer 55(A) between downstream units viewed from the wireless communication unit 1(B)). A channel between upstream units (which is a channel between downstream units when viewed from the wireless communication unit 1(B)) set for a radio bearer) is set to CH1, which is different from CH2 and CH5. At this time, by setting the downstream inter-unit channel CH1 and the upstream inter-unit channels CH2 and CH5 as mutually different frequency channels within the same band, the radio base station section 4 and the relay radio communication section for constructing the inter-unit radio bearer 9 hardware can be easily configured with a single band specification.

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

Further, 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) that has become available due to the termination of terrestrial analog television broadcasting. Since band 28 is a low-frequency band, the communication speed is somewhat slow, so it has not been actively adopted in areas such as urban areas where there are many terminal subscribers, and the utilization of radio wave resources is so tight. A smooth connection can be expected. In addition, the low frequency band has excellent long-distance reachability of radio waves, and it is possible to expand the area (cell) that can be covered by one wireless communication unit. In addition, it has a characteristic that it is easy to connect even if there is an underground or obstacle, and it can be said that it is 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, wireless bearers between units adjacent to each other in upstream/downstream positional relationship as viewed from a certain wireless communication unit as shown in FIG. B) and 55(D), for example, by way of the unit-to-unit radio bearers 55(A), 55(B), 55(D). This can be done by sharing inter-unit channel information between the wireless communication units 1(A) to 1(D).

Further, when the upper limit of the number of wireless communication units participating in the wireless network system is defined, in FIG. Therefore, it is effective to uniformly determine the type of inter-unit channel to be allocated in the form of a channel map and incorporate this channel map into the EPC function section 3 of each wireless communication unit for further simplification of processing. is. Even if each EPC function part 3 does not share the channel setting information with the EPC function part 3 of another wireless communication unit, the inter-unit channel of the wireless bearer between adjacent units is different by referring to the embedded channel map. It is possible to set so as to be In this case, the EPC function unit 1 has a channel map storage unit that stores a channel map indicating the correspondence relationship between the group of frequency channels that can be selected as channels between downstream units and the node address of the downstream relay wireless communication unit that is the connection destination. and acquires the node address of the downstream relay wireless communication unit upon receiving an attach request from the downstream relay wireless communication unit, identifies the frequency channel corresponding to the acquired node address on the channel map, and identifies it. It operates to set the determined frequency channel as a downstream inter-unit channel.

FIG. 12 shows an example of a channel map 305g. The channel map 305g exemplifies a case where the number of wireless communication units 1 participating in the system construction is four, and each wireless communication unit 1 is given a node address MID01 to MID04 (in FIG. 11, Wireless communication units 1(A), 1(B), 1(C) and 1(D) correspond in this order). Then, according to the combination of these node addresses, the channel numbers of the inter-unit channels set between the corresponding wireless communication units 1 are determined so as not to overlap. 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 flow chart 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 channel between downstream units 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 channel between units on the upstream side (this channel number CH#B may be plural) is obtained from the wireless communication unit on the upstream side. In B103, UE channel numbers CH#U1, CH#U2, . . . are selected from the remaining channel numbers other than CH#M/CH#B. Then, in B104, the available channel numbers (CH#U1, CH#U2, . . . ) are notified to the radio base station section and the UE. This notification is performed in the attach sequence of the radio base station and the UE.

The flow of the attach sequence between the relay wireless communication unit 9 and the UE 5 will be described below with reference to FIGS. 14 and 15. FIG. FIG. 14 shows the attach sequence of the relay wireless communication unit 9. As shown in FIG. In this embodiment, each wireless communication unit 1 is equipped with two relay wireless communication units. It can be independently attached to the radio base station section 4 . In TS1, an attach request is issued from the relay wireless communication unit 9 to the MME 2 via the wireless base station unit (eNodeB) 4. FIG. By receiving the notification signal periodically output from the eNodeB 4, the relay wireless communication unit 9 can recognize that it has entered the cell of the eNodeB 4 (that is, within the range), and outputs an attach request to the eNodeB 4. At this time, the IP address of the wireless communication unit is transmitted to the request source. MME2 receives this and transmits a bearer setup request to S-GW6 in TS2. At TS3, S-GW6 executes bearer setting processing of a physical line on the S5 interface with P-GW7. If the bearer is set, S-GW 6 transmits a bearer setting response to MME 2 in TS4.

At TS5, the MME 2 searches the wireless communication channel corresponding to the IP address of the requesting unit on the channel map 305g (FIG. 12). Then, in TS6, a radio bearer setting request (acceptance of attach) is notified to the radio base station unit 4 together with the set channel number. The radio base station section 4 receiving this transmits to the relay radio communication section 9 MIB (Master Information Block) including the setting channel number of the radio bearer (inter-unit radio bearer) to be set in TS7. In TS8, the relay wireless communication section 9 sets the unit-to-unit channel fixedly to the setting channel number included in the received MIB, and returns setting completion. In response to this, the radio base station section 4 notifies the relay radio communication section 9 of a session start request (touch acceptance) at TS9. At TS 10 , relay radio communication section 9 sets up an inter-unit radio bearer and returns a session start response to radio base station section 4 . At TS11, the radio 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). At TS 11 ′, an attach request is issued from UE 5 to MME 2 via radio base station unit (eNodeB) 4 . At this time, the IP address of the wireless communication unit is transmitted to the request source. MME2 receives this and transmits a bearer setup request to S-GW6 in TS12. At TS13, S-GW6 executes bearer setting processing of a physical line on the S5 interface with P-GW7. When the bearer is set, S-GW6 transmits a bearer setting response to MME2 in TS14. The MME 2 determines setting channel numbers that can be used as the terminal radio bearer group according to the process of FIG. Then, in TS16, a radio bearer setup request (acceptance of attach) is notified to the radio base station section 4 together with the determined setup channel number. The radio base station section 4 receiving this transmits to the UE 5 MIB (Master Information Block) including the set channel number of the radio bearer (inter-unit radio bearer) to be set in TS17.

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 TS 20 , 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 radio 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 wireless communication unit 9 are basically executed according to the same procedure except for the contents of frequency channel setting.

In the LTE system, fixed broadcast information resources using PBCH and variably using PDSCH can be used in order to flexibly change the transmission amount of broadcast information such as the set channel number for each operation/environment. are used in combination with radio resources. The PBCH, which is a fixed resource, is used here because the broadcast information is defined as the information that the UE 5 (relay wireless communication unit 9) acquires first, and the UE 5 (relay wireless communication unit 9) uses the wireless base station unit ( This is because it needs to be able to receive without being notified by the eNodeB) 4. The UE 5 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 by the PDSCH is variable. This makes it possible to change the amount of resources used for broadcast information, and to allocate radio resources according to the amount of broadcast information that varies depending on network operation and environment.

Of the broadcast information transmitted by this PBCH, the above MIB is transmitted at the beginning of a radio frame (that is, subframe number = 0), and the time resources and frequency resources are always fixed. assigned. The transmission information is usually, for example, information for receiving other broadcast information (for example, SIB (System Information Block)) by PDSCH, a radio frame number (SFN: System Frame Number), and the like. However, in this embodiment, using this MIB, the radio base station section 4 distributes the channel information of the terminal radio bearer or inter-unit radio bearer to the UE 5 (relay radio communication section 9). The size of the MIB is fixed at 24 bits, 10 bits of which is a spare area. For example, this spare area can be used to incorporate the setup channel information of the radio bearer.

Next, as shown in FIG. 11, each EPC function section 3 of two or more wireless communication units 1(A) to 1(D) connected by an inter-unit wireless bearer 55 is connected to each of the wireless communication units 1(A) to 1(D). The addresses (terminal identification information) of the UEs 5(A), 5(D), etc. (mobile terminals) connected to the radio base station section 4 of 1(D) are sent to the unit-to-unit radio bearers 55(A), 55(B), 55(D) to another wireless communication unit. As a result, between the wireless communication units 1(A) to 1(D) of the addresses of the UEs 5(A) and 5(D) being connected between two or more wireless communication units 1(A) to 1(D) can be shared. Then, the EPC function unit 3 creates an IP packet forwarding table based on the shared address (terminal specifying information), and refers to the forwarding table to perform IP packet forwarding control.

FIG. 16 shows an example of the transfer table 305e. The forwarding table 305e includes a connected terminal registration unit 305rt in which the addresses of UEs (UEAD11, 12, . unit), the address of the wireless communication unit that is the final transfer destination of the received packet, and the address of the wireless communication unit that is the next transfer destination of the received packet ( and a routing table 305ert that stores so-called next hopping in association with each other. The neighboring unit list 305nt is for specifying the next hopping node registered in the routing table 305ert, and can be broadly regarded as forming a part of the routing table 305ert.

The information of the next hopping node indicates that, in the wireless network system of the present embodiment, the wireless communication unit to which the UE, which is the final packet transmission destination, is connected, automatically performs next hopping to the adjacent wireless communication unit on the lower side of itself. By notifying that it is a node, and receiving this, the wireless communication unit on the lower side notifies the wireless communication unit on the lower side in the same way, so that the next hopping information for each wireless communication unit is the wireless communication of the packet transmission source. It is transmitted sequentially until it reaches the unit. Each wireless communication unit writes the notified next hopping information to the routing table 305ert, and thereafter, when a packet to the same destination is transmitted, this routing table 305ert is referred to so that the next packet to the wireless communication unit Transfers run smoothly. The content of the routing table 305ert employs a dynamic routing method in which the contents are updated according to changes in the network topology, as will be described later.

FIG. 17 shows the flow of update processing of the adjacent node performed by each EPC function unit 3, and the associated update processing of the forwarding table 305e (FIG. 16). This process is realized by executing the transfer table update program 305f, and has the function of a transfer table update control unit. The outline is as follows.
(1) An IP packet forwarding table is created based on the shared terminal specifying information of the relay wireless communication unit, and IP packet forwarding control is performed by referring to the forwarding table.
(2) When at least one of the number of wireless communication units included in the wireless network system and the order of connection is changed, the content of the transfer table is updated according to the content of the change.
As a result, even when the topology of the connection state by the inter-unit bearer 55 is reversed due to changes in the number of wireless communication units 1 and the connection order, the contents of the transfer table 305e are always maintained in the optimum state. be able to.

First, when the process starts in A201, it is checked in A202 whether or not the arrangement (order or number) of the wireless communication units has changed. Specifically, it confirms whether the node address of the upstream unit or the downstream unit has changed due to a change in connection, which will be described later. On the other hand, if it has not changed, A203 is skipped. At A204, the IP address of the UE currently connected to its own node is acquired. At A205, the content of the connected terminal registration unit 305rt is updated with the obtained IP address. At A206, it is determined whether or not to end the process. If not, after waiting for a certain period of time at A207, the process returns to A202 to repeat the following processes.

FIG. 18 shows the flow of routing table update processing in each wireless communication unit 1 . The processing is performed according to the so-called RIP (Routing Information Protocol). First, when a packet is received in A101, the connected terminal registration unit 305rt is referred to in A102 to check whether the own node is a UE connection node (radio communication unit to which the UE is connected) to which the packet is addressed. to judge. In A102, if the own node is the packet destination UE connection node, the process proceeds to A103 to transfer the packet to the destination UE. In addition, in A104, to all adjacent nodes (generally plural) which are wireless communication units connected to itself, the self node is the connection node of the UE, which is the final destination of the packet, that is, the destination node. , by transmitting the address of its own node (NHP address to be described later), and in S105 it is notified that the hopping number n is 1.

On the other hand, if the own node is not the packet destination UE connecting node at A102, the process proceeds to A106 to refer to the routing table 305erf (FIG. 16), and at A107 whether the next hopping node corresponding to the destination node is registered. to examine. If not registered, proceed to A108, determine one of the adjacent nodes as the next hopping node, associate it with the address of the destination node, and register it in the routing table. On the other hand, if the next hopping node corresponding to the destination node is registered in A107, A108 is skipped. In either case, at A109, the packet is transferred to the next hopping node corresponding to the destination node.

A110 receives notifications from all neighboring nodes indicating that they are the next hopping nodes to the destination node together with the node address (next hopping address: also referred to as NHP address) and the hopping number n. At A111, it is checked whether or not the received hopping number n includes a value smaller than the value already registered in the routing table. If there is a hopping number smaller than the registered value, proceed to A112 and update the NHP address and hopping number corresponding to the destination node on the routing table using the received value. Then, in A113, all adjacent nodes (excluding the adjacent node that has made the notification) are notified that they are next hopping nodes by transmitting their own node addresses (NHP addresses), and furthermore, the number of hopping 1 is added to and notified. If the process is not finished in A114, the process returns to A101, and the following processes are repeated.

According to RIP, as shown in FIG. 35, when the packet reaches the destination node, the destination node DT directs to all the adjacent nodes NT11 to NT13 by steps A104 and A105 in FIG. It notifies that it is the destination node by sending the NHP address, and also notifies that the hopping (HP) number n is one. Each of the adjacent nodes NT11 to NT13 that has received this notification informs the adjacent node NT21 other than the source node of the notification that it is the next hopping node to the destination node DT using its own node address (NHP address). , and adds 1 to the received hopping number n and notifies it. When this process is successively executed for subsequent adjacent nodes, finally, each adjacent node corresponding to a plurality of routes from the destination node DT to the packet transmission source node ST is provided to the packet transmission source node ST. NHP addresses and hopping numbers n1 to n3 are notified from NS1 to NS3, respectively. In the packet source node ST, the NHP address of the adjacent node corresponding to the route with the smallest number of hops n1 to n3 is associated with the address of the destination node DT along with the number of hops, and is stored in the routing table 305ert of FIG. Remember.

For example, in the example shown in FIG. 31, the number of wireless communication units 1 passing through from the wireless communication unit 1 forming the source node ST to the wireless communication unit 1 forming the destination node DT, that is, the number of hops is 9, 6 for route RT2, 8 for route RT3, and 9 for route RT4. Information on the next hopping node of route RT2 with the smallest number of hops is automatically registered in the routing table of each node. becomes. That is, the wireless communication unit that is the final transfer destination of the packet is the destination node DT, and the plurality of wireless communication units 1 leading to the destination node DT are the relay nodes VT. With the wireless communication unit to be the transfer destination as the next hopping node, each wireless communication unit 1 selects the next hopping node corresponding to the destination node DT in the routing table so that the route is optimized in the direction of decreasing the number of relay nodes VT. It is clear that the function of the routing table updating unit for updating and setting the address of the router is provided. As a result, in a wireless network system in which a plurality of moving wireless communication units 1 are wirelessly connected, dynamic routing of packet transfer can be performed without any problem even when the connection topology changes.

Next, FIG. 19 shows the flow of IP packet transmission processing between UEs 5 (UE(I) and UE(II)) connected to the same wireless communication unit 1. In FIG. U1 and U2 are the attach sequences already explained with reference to FIG. 15, and the radio bearer for the terminal is established. At U3, an IP packet is sent from UE(I) to the radio base station unit 4 as an uplink packet. The radio base station section 4 transfers this to the EPC function section 3 . The EPC function unit 3 refers to the connected terminal registration unit 305rt in FIG. Check if it matches the destination address. In the case of FIG. 19, the IP address of UE (II) corresponds to this, and at D1, the IP packet is forwarded back to the subordinate radio base station section 4 as a downstream packet. The radio base station section 4 receives this and transfers it to UE (II), and the process is completed.

FIG. 20 shows an 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. It shows the flow. The processing from U1 to U3 is the same as in FIG. At U3, the EPC function unit 3 of the wireless communication unit 1(A) refers to the connected terminal registration unit 305rt, and the destination address of the received IP packet indicates which of the wireless communication units 1(A) to which it belongs is currently connected. Also, by referring to the routing table 305ert, it is confirmed that the next hopping is the wireless communication unit 1 (B) on the upstream side. Then, in U4, the IP packet is transferred to the wireless communication unit 1(B) on the upstream side by the inter-unit wireless bearer 55(A). The wireless communication unit 1 (B) receives this IP packet, similarly refers to the connected terminal registration section 305rt, and confirms that the IP address of the UE 5 (B) matches the IP address of the destination. Then, at D2, the IP packet is transferred to the subordinate wireless base station section 4 as a downstream packet. The radio base station section 4 receives this and transfers it to the UE 5 (B), completing the process.

For example, the source UE of the IP packet is connected to an intermediate one of the connected wireless communication units, and the destination UE is connected to a wireless communication unit downstream of the wireless communication unit. , the EPC function unit 3 in the UE refers to the connected terminal registration unit 305rt, and the destination address of the received IP packet is the IP address of any UE connected to the wireless communication unit to which it belongs. , and by referring to the routing table 305ert, it is confirmed that the next hopping is the wireless communication unit on the downstream side. Then, the IP packet is transferred to the radio base station section 4 as a downstream packet, and further transferred to the radio communication unit to which the UE, which is the destination, is connected using the unit-to-unit radio bearer on the downstream side.

FIG. 21 shows an IP packet between UE 5 (A) currently connected to wireless communication unit 1 (A) and UE 5 (C) currently connected to wireless communication unit 1 (C) two ahead in FIG. It shows the flow of transmission processing. The processing from U1 to U4 is the same as in FIG. In U5, the EPC function unit 3 of the wireless communication unit 1(B) refers to the connected terminal registration unit 305rt, and the destination address recorded in the header of the received IP packet is registered to the wireless communication unit 1(B) to which the unit belongs. ), and U5 transfers the IP packet to the upstream wireless communication unit 1(C) via the unit-to-unit wireless bearer 55(B). The wireless communication unit 1 (C) receives this IP packet, similarly refers to the connected terminal registration section 305rt, and confirms that the IP address of the UE 5 (C) matches the destination IP address. Then, at D3, the IP packet is transferred to the subordinate wireless base station section 4 as a downstream packet. The radio base station unit 4 receives this and transfers it to the UE 5 (C), completing the process.

Further, 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 (for example, a global public network (Internet)) via a satellite communication line 61, for example. is. With this configuration, it is also possible to transfer IP packets whose destination is a network other than the wireless network system of the present invention. In FIG. 11, router 8 of wireless communication unit 1 (D) is connected to external network 60 .

Next, the aforementioned simple handover processing will be described.
As already explained using FIG. 2, in this embodiment, one wireless communication unit 1 (A) and the other wireless communication unit 1 (B) forming a wireless communication unit pair are connected only by the unit-to-unit wireless bearer 55. It is configured to be connected for communication. That is, between the radio base station sections 4, 4 of the radio communication unit pair 1(A), 1(B), the control interface for directly connecting them is omitted (that is, the conventional X2 interface is not provided). . Therefore, when the mobile terminal 5(A) connected to the radio communication unit 1(A) in FIG. 11 moves into the communication cell 50B of the radio communication unit 1(B), normal handover processing using the X2 interface is performed. cannot be implemented. 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 to the radio communication unit 1(A) to establish 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 that connects the radio base station section 4 of the radio communication unit 1 (A) and the UE5 (mobile terminal). When the UE 5 detects the communication unit 1(B), the UE 5 issues a new attach request to the wireless communication unit 1(B) in U1'. By receiving this attach request, the radio communication unit 1 (B) establishes a new terminal radio bearer with the UE 5 based on the same processing as that of U2. That is, based on a command from the EPC function unit 3 of the wireless communication unit 1(B), the terminal is placed between the wireless base station unit 4 of the wireless communication unit 1(B) and the UE 5(A) (mobile terminal) after movement. radio bearer is reconstructed. It can be seen from the above processing that the substantial handover processing accompanying the inter-cell movement of the UE 5 can be realized even in an environment where there is no inter-base-station interface.

A specific example of changing the topology of the connection of wireless communication units in the system in a state where the wireless network system of the present invention is constructed will be described below. Here, a case is taken as an example in which the upper limit of the number of other wireless communication units (relay wireless communication sections of) that can be connected to the wireless base station section of one wireless communication unit is set to two. In state A1 of FIG. 23, three wireless communication units 1(B) to 1(D) are connected by inter-unit wireless bearers 55(B) and 55(C). The eNodeB 4 of the wireless communication unit 1 (B) is in a state in which no other wireless communication unit is connected, and up to two new wireless communication units can be connected.

In addition, a plurality of (here, two) relay wireless communication units 9 (represented as A1/A2, B1/B2, etc. in the figure) of each wireless communication unit 1(B) to 1(D) are wireless One of the communication units 1(B) to 1(C) is attached to the wireless base station section 4 of the upstream unit, and the others are not connected. Moreover, all the relay wireless communication sections 9 of the wireless communication unit 1 (D) at the end are in a non-connected state. If there is any other connectable wireless communication unit, these unconnected relay wireless communication units 9 can be attached to the wireless base station of the wireless communication unit. At this time, an identification ID is assigned to a plurality of relay wireless communication units 9 belonging to the same wireless communication unit 1, and when attaching to another wireless communication unit, which relay wireless communication unit 9 is preferentially attached. The order of attachment indicating whether to continue is determined among the identification IDs (in the present embodiment, the order of attachment of the relay wireless communication unit 9 with the smaller number indicated by the identification ID is determined higher). Further, when a plurality of relay wireless communication units 9 are not connected and there are a plurality of wireless communication unit candidates to be attached, the relay wireless communication unit 9 having a higher attach order is selected by CQI, which will be described later. It is defined that priority should be given to wireless communication units with better communication quality.

In FIG. 23, a new wireless communication unit 1(A) is approaching the leading wireless communication unit 1(B). When the relay wireless communication unit 9 enters the range of the eNodeB 4 of the wireless communication unit 1(B), the relay wireless communication unit 9 outputs an attach request to the eNodeB 4 of the wireless communication unit 1(B). 14 is executed, and the inter-unit radio bearer 55(A) is established between the radio communication unit 1(A) and the radio communication unit 1(B) as in state A2. Then, the wireless communication unit 1(A) is incorporated into the wireless network system. For example, in state A2, the wireless communication unit 1 (A) newly includes three (two in the wireless base station section 4 and one in the relay wireless communication section 9) wireless communication units 1 (B) to 1 ( As for D), it is possible to newly connect two wireless communication units (one to the wireless base station section 4 and one to the relay wireless communication section 9).

In state B1 of FIG. 24, three wireless communication units 1(A) to 1(C) are connected by inter-unit wireless bearers 55(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 another new wireless communication unit can be connected. Then, when the relay wireless communication section 9 of the approaching wireless communication unit 1(D) enters the range of the wireless base station section 4 of the approaching wireless communication unit 1(C), the relay of the wireless communication unit 1(D) The wireless communication unit 9 transmits an attach request to the eNodeB 4 of the wireless communication unit 1(C). After that, the attach sequence already explained in FIG. 14 is executed, and the unit-to-unit radio bearer 55 ( C1) is constructed and taken into the wireless network system in the form of branching wireless communication unit 1(D). Furthermore, in the same way, by attaching the unconnected one (A2) of the relay wireless communication section 9 of the wireless communication unit 1 (A) to the wireless base station section 4 of the wireless communication unit 1 (D), the inter-unit wireless bearer 55 ( C2) is constructed, and the three wireless communication units 1(A) to 1(D) form a ring-shaped wireless communication net. FIG. 25 also shows a situation where wireless communication unit 1(C) attaches to yet another wireless communication unit 1(E).

For example, in FIG. 23, the newly added wireless communication unit is connected to a wireless communication unit (reference numeral 1 (A) in FIG. 23) that constitutes the head of the established wireless communication network system, that is, the edge of the network. 1 shows an embodiment for This method has the advantage that the addition of the wireless communication unit does not affect the connection order of the wireless communication units in the existing network and is simple. However, since the wireless communication unit to be added is attached and connected only when it approaches the wireless communication unit that constitutes the edge, there is a drawback that the flexibility for adding new wireless communication units is rather poor. However, if a plurality of relay wireless communication units 9 can be independently attached to the wireless base station unit 4 of another wireless communication unit 1, wireless communication is possible in which some of the relay wireless communication units 9 are already blocked due to attachment. A unit can be attached to another wireless communication unit as long as another relay wireless communication section 9 has a vacant space, and the connection topology can be changed very easily as the number of wireless communication units increases. On the other hand, since a plurality of (relay wireless communication units of) wireless communication units (relay wireless communication units) that can be attached/connected to the wireless base station unit 4 are allowed, there is a degree of freedom in changing the connection topology as the number of wireless communication units increases. is increasing further.

On the other hand, when there is a switching candidate unit that is a wireless communication unit different from the upstream unit and that 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 the connection to FIG. 26 shows, as the simplest case, 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), as in state C1. In the case of moving apart as in state C2 and leaving the network system as in state C3 (or when communication becomes impossible due to a failure or the like: this can also be said to be a kind of "leaving"), the remaining wireless It shows the reconnection process of communication units 1(A), 1(B), 1(D).

When the radio communication unit 1(C) is disconnected as described above, the quality of communication between the upstream unit (the radio communication unit 1(D) in FIG. 26) and the radio communication unit 1(C) deteriorates. The connection of the inter-unit radio bearer 55(C) is disconnected. As a result, the wireless network system is divided into two network clusters CR1 and CR2 each having two new edges, the two wireless communication units 1(B) and 1(D) connected to the disconnected wireless communication unit 1(C). decompose into Also, the wireless communication unit 1(D) once isolated due to the disconnection becomes a switching candidate unit when viewed from the nearest remaining wireless communication unit 1(B). In this case, as in state C3, the wireless communication unit 1 (B) that forms the edge of one network cluster CR1 issues an attach request to the wireless communication unit 1 (D) that forms the edge of the other network cluster CR2. As in state C4, a new inter-unit radio bearer 55 (B') is constructed between the radio communication unit 1 (B) and the radio communication unit 1 (D), and the two network clusters CR1 and CR2 are reconnected. complete.

FIG. 26 shows a simple case in which the wireless communication unit 1 (B) is the only switching candidate unit resulting from the withdrawal of the wireless communication unit 1 (C). Due to the movement of (A), 1(B), and 1(D), for example, a plurality of switching candidate units seen from the wireless communication unit forming the edge of either network cluster CR1 or CR2 may occur. Also, 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 approaching point become switching candidate units. There is also

Here, in order to change the connection from the radio base station section that is the connection destination of the relay radio communication section to the radio base station section of another radio communication unit, the inter-unit radio bearer that has already been established is once disconnected, and In some cases, a new inter-unit radio bearer must be re-established between the radio base station section of the radio communication unit to be used. At this time, when another wireless communication unit outside the network approaches a wireless communication unit whose number of downstream unit connections has reached the upper limit (two in this embodiment), the unit-to-unit wireless bearer is disconnected. , depending on the situation, the upstream wireless communication unit side can be forcibly executed by the instruction of the EPC function unit, and the optimization of the connection topology between the wireless communication units by restructuring the wireless bearer between units can be performed. It is easy to plan. Specifically, the EPC function section instructs the radio base station section to temporarily and forcibly disconnect the radio bearer between the downstream units (FIG. 3: function of the network adjustment program 305h). Upon receipt of the instruction, the base station section performs disconnection control of the radio bearer between downstream units. In this case, the upstream unit connection switching control section, along with the disconnection of the upstream unit wireless bearer, controls the former upstream unit, which is a wireless communication unit connected as an upstream unit by the upstream unit wireless bearer, and the switching candidate unit. , and a wireless communication unit to be connected as a new upstream unit is determined based on the result of the communication quality evaluation (function of the upstream unit connection switching control program 905b).

An example is shown in FIGS. 27 to 29. FIG. In state D1 of FIG. 27, five wireless communication units 1(A), 1(B), 1(C), 1(E), and 1(F) are inter-unit wireless bearers 55(A), 55(B). , 55(D) and 55(E), with a new wireless communication unit 1(D) approaching midway between wireless communication unit 1(B) and wireless communication unit 1(C). . The two relay radio communication sections 9 (B1, B2) of the radio communication unit 1(B) are attached to the radio communication units 1(E) and 1(C), and the radio base of the radio communication unit 1(B) The number of connections of downstream units to the local section 4 has also reached its upper limit. Therefore, it is impossible for the wireless communication unit 1(D) to connect to the wireless communication unit 1(B) and the wireless communication unit 1(C). In this situation, for example, the downstream unit-to-unit wireless bearer forced disconnection instruction section of the wireless communication unit 1(C) to which the two downstream units 1(B) and 1(F), which are the upper limit number, are already connected acquires downstream unit distance information reflecting the distances dc1 and dc2 from the downstream units 1(B) and 1(F) (downstream unit distance information acquisition section), and wireless communication unit 1(D) which becomes a switching candidate unit (switching candidate unit distance information acquiring section). In state D1, d1>dc1, dc2.

Then, as in state D2 in FIG. 28, the distance d1 to the switching candidate unit reflected in the acquired switching candidate unit distance information is the distance (for example, When the distance to the downstream unit 1(B) is smaller than dc1, the EPC function unit 3 of the wireless communication unit 1(C) sends the wireless base station unit 4 a wireless bearer between downstream units (55(B)). is temporarily and forcibly disconnected. As a result, as in state D3, when the switching candidate unit (1(D)) comes closer than the already connected downstream unit (1(C)), the above distance determination determines whether the wireless bearer between the downstream units is forcibly disconnected, and as in state D4 of FIG. The communication quality and throughput of bearers can be greatly enhanced.

Various methods for acquiring the downstream unit distance information and the switching candidate unit distance information can be selected. is provided, a downstream unit distance information acquisition unit and a switching candidate unit distance information acquisition unit acquire the current positions of the downstream unit and the switching candidate unit, and based on the information of their current positions, the distance to the downstream unit and switching A method of calculating each distance to a candidate unit can be exemplified. In this embodiment, as shown in FIG. 3, the radio base station section 4 of each radio communication unit 1 is provided with a GPS 413 (connected to the bus 405) serving as a current position acquisition section. The unit 1 (C) can acquire the location information of the downstream unit 1 (B) as GPS information via the wireless bearer between downstream units (55 (B)). Further, 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. 33 shows an example of the flow of processing for forcibly disconnecting the wireless bearer between downstream units in this case by the network adjustment program 305h. In FIG. 28 (state D2), it is the EPC function section 3 of the wireless communication unit 1 (D) that performs the processing. C200 acquires its own location information from GPS 413 (FIG. 3). Note that this location information is uploaded to an external network 60 (FIG. 3) for use by other wireless communication units in distance calculations. In C201, it is determined whether or not the number of downstream units receiving attachment/connection has reached the upper limit (eg, 2 in this embodiment). If the number has reached the upper limit, the process advances to C202 to acquire the location information of the connected downstream unit 1(B) (FIG. 28) via the unit-to-unit radio bearer 55(B), A distance dc is calculated based on the information.

Then, in C203, the position information of the surrounding switching candidate unit (wireless communication unit 1(D) in FIG. 3) 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 to temporarily disconnect the unit-to-unit wireless bearer 55(B) with the connected downstream unit 1(B) (FIG. 28) (FIG. 28: state D2). In C205, if d1<dc, C206 is skipped. On the other hand, in C201, if the number of downstream units that are attached/connected has not reached the upper limit, a new bearer between downstream units can be additionally constructed, so forced disconnection processing is unnecessary, and the process jumps to C207. If the process is not completed in C207, the process returns to C200 and the following processes are repeated.

As in the state D2 of FIG. 28, when the inter-unit wireless bearer is disconnected as described above, one (B2) of the relay wireless communication units 9 of the old downstream unit 1 (B) edged by this is transferred to the upstream unit According to the connection switching control program 905b (FIG. 3: upstream unit connection switching control section), the old upstream unit 1, which is a wireless communication unit connected as an upstream unit by the wireless bearer between upstream units 55(B), as in state D3. (C) and the switching candidate unit 1 (D) are each evaluated for communication quality, and based on the result of the communication quality evaluation, a process for determining a wireless communication unit to be connected as a new upstream unit is performed. 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, communication quality evaluation. In the case of LTE terminals (UE and relay radio communication unit), the CQI information measurement and generation processing function is indispensable for the resource block scheduling algorithm as described above, and is also incorporated in the 3GPP protocol as a standard specification. There is an advantage that this can be diverted. However, in the LTE protocol, the CQI is measured after the terminal attaches to the radio base station. It is necessary to devise the processing of

FIG. 34 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 constitutes the former downstream unit that performs the processing. The radio base station sections 4 of the radio communication units 1(C) and 1(D), which are candidates for connection, output notification information for accepting attachment of the UE 5 or the relay radio 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. In the resource block matrix of FIG. 10, this reference signal is a specific symbol (for example, symbols "0" and "4") in each slot on the time axis, and uses subcarriers of predetermined frequencies. inserted. Therefore, if the symbol number in the slot for acquiring the reference signal and the frequency subcarrier specific information are incorporated in the broadcast information, the relay wireless communication unit 9 of the wireless communication unit 1(B) can can be read and reception setting processing of the reference signal for CQI measurement can be performed.

Returning to FIG. 34, at C102, it is confirmed whether or not the CQI reference signal is received. If so, the process proceeds to C103 to determine whether or not CQI reference signals are received from a plurality of wireless communication units. If so, proceed to C104 and perform CQI measurements for each CQI reference signal. Then, proceeding to C105, 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, as a result of being closest to the wireless communication unit 1 (B), the wireless communication unit 1 (D) having the best coding rate and frequency utilization efficiency reflected in the CQI information (see FIG. 32) is requested to attach. , an inter-unit radio bearer 55 (B') is established between the radio communication unit 1 (D) and the radio communication unit 1 (D). On the other hand, if the CQI reference signal is not received from a plurality of wireless communication units in C103, that is, if the CQI reference signal is received only from one wireless communication unit, the process proceeds to C106, and regardless of the CQI measurement result, the Make an attach request. If the process is not finished in C107, the process returns to C101, and the following processes are repeated.

Although the embodiment of the present invention has been described above, it is merely an example, and the present invention is not limited to this. For example, the contents of the downstream unit-to-unit wireless bearer forced disconnection processing are not limited to those described above, and the EPC function unit of the upstream unit periodically outputs an instruction to disconnect the downstream unit-to-unit wireless bearer at predetermined time intervals. It can also be configured as The radio base station section periodically disconnects the radio bearer between the downstream units (for example, once every hour to a year, preferably every three hours to three months, etc., so as to minimize the impact on communication quality). The flow of processing after the downstream inter-unit radio bearer is disconnected is the same as that already described.

Further, in the radio communication units 1′(A) to 1′(C) shown in FIG. are provided. In FIG. 36, the wireless communication unit 1'(A) is the upstream unit, and the wireless communication unit 1'(B) as the downstream unit is connected to the wireless base station section 4(X) by an inter-unit wireless bearer 55. (X), and the radio communication unit 1'(C) is connected to the radio base station section 4(Y) by constructing an inter-unit radio bearer 55(Y). In this case, the unit-to-unit radio bearer 55(X) and the unit-to-unit radio bearer 55(Y) can be set to different frequency channels. As a result, the communication capacity (throughput) between the inter-unit radio bearer 55(X) and the inter-unit radio bearer 55(Y) can be greatly increased.

1(A), 1(B) Wireless communication unit WS(A), WS(B) Large vessel 2 MME
3 EPC function unit 301 CPU
302 RAMs
303 Mask ROM
304A upstream side communication interface 304B downstream side 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 transfer table update program 305g channel map 306 bus 21 secondary battery module 22 Power supply circuit unit 23 Portable housings 30, 31 Communication bus 4 Wireless base station unit 401 CPU
402 RAMs
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 unit 901 CPU
902 RAM
903 Mask ROM
905 Flash memory 905a Communication firmware 906 Bus 912 Wireless communication units 50(A), 50(B) Communication area 55 Wireless bearer between units 57 Wireless bearer for terminal

Claims (20)

A wireless communication unit configured to be mountable on a mobile object 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 connected by wire to the radio base station unit and functioning as an upper network control unit for the radio base station unit;
The wireless base station section of the upstream unit (hereinafter referred to as the upstream wireless base station section) and the upstream inter-unit wireless bearer (hereinafter referred to as the upstream unit a plurality of relay radio communication units connectable via a radio bearer),
The radio base station section includes a relay radio communication section of a downstream unit, which is a second separate radio communication unit (hereinafter referred to as a downstream relay radio communication section) and a downstream inter-unit radio bearer (hereinafter referred to as a downstream inter-unit radio bearer). ) and can be connected via
The EPC function unit transmits a wireless bearer setting request between downstream units to the wireless base station unit, while the wireless base station unit receives the wireless bearer setting request between downstream units and performs wireless communication between downstream units together with the downstream relay wireless communication unit. which constructs the bearer,
The EPC function unit transmits a terminal radio bearer setting request to the radio base station unit, and the radio base station unit receives the terminal radio bearer setting request and constructs the terminal radio bearer together with the mobile terminal. can be,
The plurality of relay wireless communication units receive a wireless bearer setting request between upstream units issued by an EPC function unit of the upstream unit (hereinafter referred to as an upstream EPC function unit), and receive the wireless bearer setting request between upstream units. A wireless communication unit that independently builds the wireless bearer between upstream units together with the upstream wireless base station section. 2. The wireless communication unit according to claim 1, wherein the plurality of relay wireless communication units are capable of individually constructing the upstream unit-to-unit wireless bearer between different upstream wireless base station units. The plurality of relay radio communication sections, when detecting a candidate for an upstream unit to be a new connection destination while the upstream unit is in a non-connected state, transmit the radio bearer between the upstream units to the radio base station section of the candidate for the upstream unit. By transmitting an attach request for constructing a radio bearer construction control between upstream units, receiving the radio bearer setting request between upstream units from the upstream unit candidate and constructing the radio bearer between upstream units. 3. A wireless communication unit as claimed in claim 1 or claim 2, each comprising a section. 4. The radio base station section according to any one of claims 1 to 3, wherein the relay radio communication section of a plurality of the downstream units can be simultaneously connected via individual inter-downstream-unit radio bearers. wireless communication unit. When the radio base station unit receives an attach request from a candidate for a downstream unit to be newly connected in a state in which the number of downstream units connected is one or less, the radio base station unit notifies the EPC function unit of the attach request. an inter-downstream unit radio bearer construction control section that receives the terminal radio bearer setup request from the EPC function section and performs control for constructing the inter-downstream unit radio bearer with the candidate for the downstream unit. A wireless communication unit according to claim 4. 4. The radio communication unit according to any one of claims 1 to 3, wherein a plurality of said radio base station sections are connected to one EPC control section, each of which can be connected to a relay radio communication section of said downstream unit. . 7. A plurality of said radio base station sections connected to one said EPC control section are connected to said relay radio communication sections of said downstream units by said inter-downstream unit radio bearers set on mutually different frequency channels respectively. A wireless communication unit as described. When there is a switching candidate unit which is a wireless communication unit different from the upstream unit and which can be wirelessly connected with higher quality than the upstream unit, the relay wireless communication unit selects the switching candidate as a new upstream unit. 8. The wireless communication unit according to any one of claims 1 to 7, further comprising an upstream unit connection switching control section that switches connection to the unit. 9. The wireless communication unit according to claim 8, wherein the upstream unit connection switching control section switches the connection to the switching candidate unit as the connection with the upstream unit is cut due to deterioration of communication quality with the upstream unit. . The EPC function unit includes a downstream inter-unit radio bearer forced disconnect instruction unit that instructs the radio base station unit to temporarily and forcibly disconnect the inter-downstream unit radio bearer with the downstream unit; The radio base station section includes a downstream unit radio bearer disconnection control section that receives the instruction and performs control to disconnect the radio bearer between downstream units,
The upstream unit connection switching control unit, when the upstream unit-to-unit wireless bearer is disconnected, controls the former upstream unit, which is a wireless communication unit connected as the upstream unit by the upstream unit-to-unit wireless bearer, and the switching candidate. 10. The wireless communication unit according to claim 8, wherein communication quality evaluation is performed for each of the units, and a wireless communication unit to be connected as a new upstream unit is determined based on the result of the communication quality evaluation. The upstream unit connection switching control unit receives a CQI (Channel Quality Indicator) reference signal from each wireless communication unit, generates CQI information using the CQI reference signal, and performs the communication based on the content of the CQI information. 11. The wireless communication unit of claim 10, wherein quality assessment is performed. The EPC function unit is configured for the relay radio communication units of the plurality of mobile terminals and other radio communication units connected to the radio base station via the terminal radio bearers within the communication area of the radio base station. is provided with a connected terminal registration unit for registering the terminal identification information of the connected mobile terminals, and the mobile terminal to be the destination of the IP packet transferred from the radio base station unit is registered in the connected terminal registration unit. When the destination mobile terminal indicates a mobile terminal corresponding to any of the terminal identification information registered in the connected terminal registration unit, the IP packet is sent to the mobile terminal. When the mobile terminal to be the transmission destination indicates a mobile terminal that is not registered in the connected terminal registration unit, the IP packet is transferred to the relay wireless communication unit and the wireless communication unit. 12. The radio communication unit according to any one of claims 1 to 11, wherein control is performed to transfer data from at least one of base station sections to a destination outside said radio communication unit. A wireless network system configured to be mountable on a mobile object and comprising a wireless communication unit 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 connected by wire to the radio base station unit and functioning as an upper network control unit for the radio base station unit;
The wireless base station section of the upstream unit (hereinafter referred to as the upstream wireless base station section) and the upstream inter-unit wireless bearer (hereinafter referred to as the upstream unit a plurality of relay radio communication units connectable via a radio bearer),
The radio base station section includes a relay radio communication section of a downstream unit, which is a second separate radio communication unit (hereinafter referred to as a downstream relay radio communication section) and a downstream inter-unit radio bearer (hereinafter referred to as a downstream inter-unit radio bearer). ) and can be connected via
The EPC function unit transmits a wireless bearer setting request between downstream units to the wireless base station unit, while the wireless base station unit receives the wireless bearer setting request between downstream units and performs wireless communication between downstream units together with the downstream relay wireless communication unit. While the EPC function unit transmits a terminal radio bearer setting request to the radio base station unit, the radio base station unit receives the terminal radio bearer setting request and transmits the terminal together with the mobile terminal. builds a radio bearer for
The plurality of relay wireless communication units receive a wireless bearer setting request between upstream units issued by an EPC function unit of the upstream unit (hereinafter referred to as an upstream EPC function unit), and receive the wireless bearer setting request between upstream units. comprising a radio communication unit group in which a plurality of radio communication units configured individually so as to individually construct radio bearers between upstream units together with the upstream radio base station section are arranged;
The radio communication unit group is connected by the inter-unit radio bearer in a positional relationship in which base station cells of pairs of radio communication units adjacent to each other partially overlap,
A mobile terminal connected to one of the wireless communication unit pair and a mobile terminal connected to the other wireless communication unit pair transmit and receive IP packets via the wireless communication unit pair and the unit-to-unit wireless bearer connecting the wireless communication unit pair. A wireless network system characterized by performing 14. The radio network system according to claim 13, wherein in at least one of said radio communication units, a plurality of said relay radio communication sections are connected to said radio base station sections of said different upstream units by said inter-unit radio bearers. The radio base station section allows the relay radio communication sections of a plurality of the downstream units to be simultaneously connected via individual inter-downstream-unit radio bearers, and at least one of the radio communication units includes: 15. The wireless network system according to claim 14, wherein a plurality of said downstream units different from each other are connected by said unit-to-unit radio bearer. 16. The wireless network system according to claim 15, wherein a plurality of said wireless communication units are connected in mesh form by said inter-unit wireless bearer. Each of the EPC function units of the plurality of wireless communication units connected by the inter-unit wireless bearer is connected to the wireless base station via the terminal wireless bearer within the communication area of the wireless base station. IP transferred from the radio base station unit, comprising a connected terminal registration unit for registering terminal identification information of the mobile terminals being connected to the relay radio communication units of the plurality of mobile terminals and other radio communication units; The destination mobile terminal of the packet is collated with the registration contents of the connected terminal registration unit, and the destination mobile terminal corresponds to any of the terminal identification information registered in the connected terminal registration unit. When indicating a mobile terminal, the IP packet is forwarded to the mobile terminal in the form of being looped back by the radio base station unit, while the destination mobile terminal is not registered in the connected terminal registration unit. 17. Control is performed to transfer the IP packet from at least one of the relay radio communication unit and the radio base station unit to a destination outside the radio communication unit when indicating The wireless network system according to . The EPC function unit creates a forwarding table of the IP packet based on the shared terminal identification information of the relay wireless communication unit, refers to the forwarding table, and performs forwarding control of the IP packet, A transfer table update control unit for updating the contents of the transfer table in accordance with the change when at least one of the number of the wireless communication units included in the wireless network system and the order of connection is changed . 18. The wireless network system of claim 17. In each wireless communication unit, the transfer table includes a connected terminal registration section in which addresses of mobile terminals currently connected are registered in a list form, and a wireless communication unit as a final transfer destination of a received packet. and a routing table that stores the address of the wireless communication unit to be the next transfer destination of the received packet in association with each other. 19. The wireless network system according to claim 18, further comprising a routing table changing unit that changes the content of said routing table in accordance with said change when at least one of (1) is changed . A wireless communication unit to be the final transfer destination of the packet is defined as a destination node, and a plurality of the wireless communication units leading to the destination node are defined as relay nodes, and a next transfer destination when the packet is transmitted to the destination node. with each wireless communication unit as the next hopping node, each wireless communication unit receives the address of the next hopping node corresponding to the destination node in the routing table so that the route is optimized in the direction of decreasing the number of the relay nodes. 20. The wireless network system according to claim 19, further comprising a routing table updating unit that updates and sets the .

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