JP7295709B2 - 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 cooperative 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 also wirelessly connected to each other, no consideration is given at all to the incorporation or removal of a new wireless communication unit or the change in the connection order of the 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. To provide a wireless communication unit capable of flexibly coping with changes in the order, etc., and a wireless network system using the unit.

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 relay wireless communication unit that can be connected via a wireless communication unit, and the wireless base station unit is a 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 unit on the downstream side. A connection is possible via a radio bearer (hereinafter referred to as a radio bearer between downstream units), and the EPC function part transmits a radio bearer setting request between downstream units to the radio base station part, while the radio base station part performs radio bearer setting between downstream units. In response to the request, a radio bearer between downstream units is constructed together with the downstream relay radio communication section. Upon receipt of the request, a terminal radio bearer is constructed together with the mobile terminal. receiving the upstream unit radio bearer setting request, constructing a radio bearer between upstream units together with the upstream radio base station section, while the EPC function section transmits a terminal radio bearer setting request to the radio base station section The radio base station receives a terminal radio bearer setting request and constructs a terminal radio bearer together with the mobile terminal. When a unit candidate is detected, an attach request for establishing a radio bearer between upstream units is transmitted to the radio base station section of the candidate for the upstream unit, thereby making a radio bearer setting request between the upstream units from the candidate for the upstream unit. and constructing a radio bearer between upstream units. When receiving the attach request, the downstream unit notifies the EPC function unit of the attach request, receives the terminal radio bearer setting request from the EPC function unit, and controls the construction of the radio bearer between downstream units. is provided with an inter-radio bearer construction control unit,
When there is a switching candidate unit which is a wireless communication unit different from the upstream unit and is wirelessly connectable with higher quality than the upstream unit, the relay wireless communication unit connects to the switching candidate unit as a new upstream unit. The EPC function unit instructs the wireless base station unit to temporarily and forcibly disconnect the downstream unit wireless bearer between the downstream unit and the downstream unit. A radio bearer forced disconnection instruction section is provided, while the radio base station section is provided with an inter-downstream unit radio bearer disconnection control section that performs control for disconnection of radio bearers between downstream units in response to the instruction. As the radio bearer is disconnected, communication quality evaluation is performed for each of the old upstream unit, which is a radio communication unit connected as an upstream unit by the inter-upstream unit radio bearer, and the switching candidate unit, and evaluation of communication quality is performed. Based on the result, a radio communication unit to be connected as a new upstream unit is determined. The upstream unit connection switching control section receives a CQI reference signal from each radio communication unit, Information is generated, and communication quality is evaluated based on the contents of the CQI information .

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 relay wireless communication 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). and the wireless base station unit includes a 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 a downstream unit 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 relays the downstream relay wireless. The EPC function unit constructs a radio bearer between downstream units together with the 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 communicates with the mobile terminal. A relay wireless communication section receives a wireless bearer setting request between upstream units issued by an EPC function section of an upstream unit (hereinafter referred to as an upstream EPC function section), and establishes a wireless bearer for a terminal. Upon receiving a radio bearer setting request, a radio bearer between upstream units is constructed together with the upstream radio base station section. In response to the bearer setting request, the terminal radio bearer is constructed together with the mobile terminal. Further, when the relay radio communication section 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 When the radio base station section receives an attach request from a downstream unit candidate to be newly connected while the downstream unit is in a state of non-connection a radio bearer construction control section between downstream units for notifying the attach request to the EPC function section, receiving a terminal radio bearer setting request from the EPC function section, and performing control for constructing a radio bearer between downstream units; The wireless communication unit group is composed of a wireless communication unit group in which a plurality of wireless communication units are arranged, and the wireless communication unit group is connected by an inter-unit wireless bearer in a positional relationship in which the base station cells of pairs of wireless communication units adjacent to each other partially overlap. , the mobile terminal connected to one of the wireless communication unit pairs and the mobile terminal connected to the other perform transmission and reception of IP packets via the wireless communication unit pair and the unit-to-unit wireless bearer connecting the wireless communication unit pair.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 has an upstream unit connection switching control section that switches connection to a candidate unit, and in each wireless communication unit, the EPC function section temporarily and forcibly establishes a wireless bearer between downstream units with respect to the wireless base station section. A downstream inter-unit radio bearer forcible disconnection instruction section is provided for instructing a forced disconnection of the radio bearer between downstream units, while the radio base station section is provided with a downstream inter-unit radio bearer disconnection control section for controlling disconnection of the radio bearer between downstream units in response to the instruction. The unit connection switching control unit, when the upstream unit-to-unit wireless bearer is disconnected, changes the connection between the old upstream unit, which is a wireless communication unit connected as an upstream unit by the upstream unit-to-unit wireless bearer, and the switching candidate unit. A communication quality evaluation is performed, and a wireless communication unit to be connected as a new upstream unit is determined based on the result of the communication quality evaluation, and the upstream unit connection switching control section receives the CQI reference signal from each wireless communication unit. and generate CQI information using the CQI reference signal, and perform communication quality evaluation based on the content of the CQI information.Characterized by The difference between the wireless bearer between upstream units and the wireless bearer between downstream units is only whether it is built upstream or downstream of the wireless communication unit of interest. The functional entity of the radio bearer that interconnects the relay radio communication section and the radio base station section is the same, and hereinafter, when collectively referred to, they are simply referred to as "inter-unit radio bearer".

In the wireless communication unit (and wireless network system) of the present invention, in its subordinate concept, the relay wireless communication unit is a wireless communication unit different from the upstream unit and can be wirelessly connected with higher quality than the upstream unit. If there is a switching candidate unit, it can be configured to have an upstream unit connection switching control section that switches connection to the switching candidate unit as a new upstream unit.

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 reference signal from each wireless communication unit, generates CQI information using the CQI reference signal, and communicates based on the content of the CQI information. It can be configured to do a quality assessment.

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 node registration unit for registering node identification information of a mobile terminal inside the mobile terminal unit; , when indicating a mobile terminal corresponding to any of the node identification information registered in the connected node registration section, the IP packet is forwarded to the mobile terminal in a form of being looped back by the radio base station section, while the destination node is When a node not registered in the connected node registration unit is indicated, control can be performed to transfer the IP packet from at least one of the relay wireless communication unit and the wireless base station unit to a destination outside the wireless communication unit.

In this case, the EPC function unit creates an IP packet forwarding table based on the shared node identification information of the relay wireless communication unit, and refers to the forwarding table to perform IP packet forwarding control. It can be configured to update the contents of the forwarding table when the number of wireless communication units included in the system is increased, decreased, and the connection order is changed.

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 with a plurality of wireless communication units. Then, when the relay wireless communication unit detects a candidate for an upstream unit to be a new connection destination while the upstream unit is in a non-connected state (that is, when forming an edge of the network), By transmitting an attach request for constructing a radio bearer between upstream units to a radio base station section of a candidate upstream unit, a radio bearer setting request between upstream units is received from the candidate upstream unit and a radio bearer between upstream units is established. can build. Further, when the radio base station receives an attach request from a downstream unit candidate to be newly connected while the downstream unit is not connected, the radio base station notifies the EPC function unit of the attach request, can receive a terminal radio bearer setup request from and establish a radio bearer between downstream units. This makes it possible to easily incorporate a new wireless communication unit into the wireless network system.

Further, in the subordinate concept invention, 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 in the relay wireless communication unit, a new As an upstream unit, an upstream unit connection switching control section for switching connection to the switching candidate unit is provided. As a result, the distance and relative positional relationship between multiple wireless communication units that are constructing a wireless network system change, or a new wireless communication unit approaches from the outside, making it possible to secure a higher quality connection state. If a possibility arises, control is performed to switch the upstream unit to be connected to a switching candidate unit that can be wirelessly connected with higher quality, making it easy to optimize the connection topology of the entire wireless network system. It is possible to improve communication quality (in particular, user throughput and throughput per cell).

In another subordinate concept invention, the EPC function unit is configured to, for a plurality of mobile terminals connected to a radio base station via a terminal radio bearer within a communication area of the radio base station unit, A connected node registration part for registering node identification information is provided, and the destination node of the IP packet transferred from the radio base station part is collated with the registered contents of the connected node registration part, and the destination node registers the connected node. When a mobile terminal corresponding to any of the node identification information registered in the unit is indicated, 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 node is connected to the node registration unit. If the node indicates a node not registered in the wireless communication unit, control is performed to transfer the IP packet from at least one of the relay wireless communication unit and the wireless base station unit to a destination outside the wireless communication unit. Each time a mobile terminal is connected, the node identification information is acquired and registered in the connected node registration unit, so that the destination of the IP packet to be transmitted is a subordinate mobile terminal or a mobile terminal outside the unit. It is easy to grasp whether As a result, the EPC function section can execute IP packet transmission control between a plurality of units without obtaining communication path information from the external network.

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. The figure which shows the flow of a transfer table update process. 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 connected to both ends of three cascaded wireless communication units. FIG. 4 is a communication flow diagram showing a control sequence for transferring an IP packet to an external network via a router of a wireless communication unit positioned at the end of three cascaded wireless communication units; FIG. 4 is a communication flow diagram showing a control sequence of simple handover processing; The figure which shows the concept of a UE list (connection node registration part). The figure which shows the flow of a UE list update process. FIG. 4 is a diagram for explaining the process of attaching/connecting a new wireless communication unit to the head wireless communication unit of the wireless communication network system; FIG. 4 is a diagram for explaining a process of attaching/connecting a wireless communication unit at the end of the wireless communication network system to the wireless communication unit; 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. 29 is an explanatory diagram following FIG. 28 ; FIG. 4 is a diagram for explaining a process of periodically disconnecting an inter-unit radio bearer and incorporating it into a network by newly attaching an approaching radio communication unit. FIG. 13 is a diagram for explaining a modification in which the timings of periodically disconnecting inter-unit radio bearers are made different among a plurality of inter-unit radio bearers; The figure which shows an example of a CQI table. 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; 4 is a flow chart showing a flow of processing for temporarily disconnecting an inter-unit wireless bearer according to an inter-unit distance based on unit position information; 4 is a flowchart showing the flow of processing for temporarily disconnecting an inter-unit radio bearer with reference to a disconnect scheduler;

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 consists of wireless communication units 1(A) and 1(B) having the same configuration, which is an embodiment of the present invention (hereinafter also referred to as wireless communication unit pair 1(A) and 1(B)), Each performs wireless communication with UE (mobile terminal) 5 in accordance with the communication protocol stack of the method specified by 3GPP (in this embodiment, LTE is used, but other methods such as WiMAX may be used). is configured as

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. Also, in the drawings attached to this specification, arrow lines indicating radio bearers are indicated by dashed lines, and wired bearers or electrical connection lines are indicated by solid or dashed-dotted arrow lines.

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 relay wireless communication unit 9 (A) connectable via 55 (wireless bearer between upstream units) is wired.

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). An EPC function unit 3(B) and a relay wireless communication unit 9(B) connected to the EPC function unit 3(B) by wire are provided. If another wireless communication unit is arranged on the upstream side of the wireless communication unit 1(B), the relay wireless communication unit 9(B) provides an inter-unit wireless bearer to the wireless base station unit of that wireless communication unit. (See FIG. 11). In addition, the wireless base station section 4 (B) provides a downstream inter-unit wireless communication to the relay wireless communication section 9 (A) (downstream relay wireless communication section) of the wireless communication unit 1 (A) (downstream unit) on the downstream side. It is connectable via a bearer 55 (radio bearer between downstream units). That is, the inter-unit radio bearer 55 is an upstream inter-unit radio bearer when viewed from the radio communication unit 1(A), and a downstream inter-unit radio bearer when viewed from the radio communication unit 1(B). Then, the unit-to-unit radio bearer 55 (the downstream unit-to-unit radio bearer and the upstream unit-to-unit radio bearer) is constructed according to the radio protocol stack of the same method as the terminal-side radio bearer 57, and in the present embodiment, both are based on the LTE radio protocol stack. be done.

Next, in any of the wireless communication units 1(A) and 1(B) (hereinafter collectively referred to as the wireless communication unit 1), the EPC function unit 3 is an MME (Mobility Management Unit) serving as a gateway on the control plane side. Entity) 2, S-GW (Serving Gateway) 6 serving as a gateway on the user plane side, EPC function unit 3, and upstream network elements of the EPC function unit 3 (here, router 8 (described later) and relay wireless communication unit 9), and has a P-GW (PDN (Packet Data Network) Gateway) 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, 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) of 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 forwarding table 305e, a connected node registering section 305f, and a channel map 305g for performing forwarding routing of IP packets.

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 , which will be described in detail in FIGS. 34 and 35).

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 .

The relay wireless communication unit 9 is mainly composed of microcomputer hardware, and includes a CPU 901, a RAM 902 serving as a program execution area, a mask ROM 903, 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: channel Quality Indicator), and, It is a physical channel used to notify the radio base station unit 4 of an uplink data 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 the UE 5 to the radio base station unit 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.

In this embodiment, as shown in FIG. 2, the number of (adjacent) eNodeBs 4 to which the relay wireless communication unit 9 of each wireless communication unit 1 can attach, that is, to which the (upstream) unit-to-unit wireless bearer 55 can be constructed is Only one is defined. Also, the number of relay wireless communication units 9 that can be connected to the eNodeB 4 is also limited to one.

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( C) and 1(D)) base station cells (50(A) and 50(B), 50(B) and 50(C), 50(C) and 50(D)) partially overlap each other. , are cascade-connected by inter-unit radio bearers 55(A), 55(B), 55(C). With this configuration, it can be easily understood that the connection topology between the wireless communication units 1 is extremely simplified. In this case, for example, UE 5 (A) (mobile terminal) connected to one of the pair of wireless communication units 1 (A) and 1 (B) and UE 5 (B) (mobile terminal) connected to the other communicate wirelessly. IP packets can be transmitted and received via the inter-unit radio bearer 55(A) connecting the unit pair 1(A), 1(B) and the radio communication unit pair 1(A), 1(B). 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.

Also, in FIG. 11, the number of wireless communication units cascade-connected by inter-unit wireless bearers 55(A), 55(B), and 55(C) is three or more (four in FIG. 11). In this case, a UE (mobile terminal) 5(A) connected to a first wireless communication unit 1(A) constituting one wireless communication unit of the wireless communication unit groups 1(A) to 1(D) and a wireless In the communication unit group 1 (A) to 1 (D), the second radio communication unit 1 (B), 1 (C) arranged with one or more intermediate radio communication units 1 (B) and 1 (C) apart from the first radio communication unit 1 (A) UEs (mobile terminals) 5(C), 5(D) connected to the wireless communication units 1(C), 1(D) of the first wireless communication unit 1(A), an intermediate wireless communication unit 1 (B), 1 (C) and second wireless communication units 1 (C), 1 (D), and inter-unit wireless bearer 55 (A ), 55(B), and 55(C). In this way, the number of cascade-connected wireless communication units can be easily increased, and IP packets can be transmitted and received by wireless communication between UEs 5 in a wider area.

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. is required to be carried out 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 in which a plurality of wireless communication units 1(A) to 1(D) are cascade-connected as shown in FIG. If there is no significant change, the wireless base station section 4 to which the relay wireless communication section 9 of each wireless communication unit 1 is connected is fixed, and handover processing involving frequency channel switching for the relay wireless communication section 9 is unnecessary. becomes. 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.

Next, in FIG. 11, what is the cell 50(A) of the wireless communication unit 1(A), the cell 50(B) of the wireless communication unit 1(B), and the cell 50(C) of the wireless communication unit 1(C)? overlap each other. In this case, for example, the unit-to-unit channel of the unit-to-unit radio bearers 55(A) and 55(B) connecting the upstream and downstream radio communication units 1(A) and 1(C) from the radio communication unit 1(B) is , by setting them to frequency channels different from each other, when building inter-unit radio bearers 55 (A) and (B), a plurality of cells 50 (A) to 50 (C) that partially overlap each other participate in this can effectively prevent radio wave interference between

More specifically, each of the EPC function units 3 of the wireless communication units 1(A) to 1(D) converts the channel between the downstream units to the wireless communication between the upstream units when the (upstream) unit-to-unit wireless bearer is constructed. A frequency channel different from the upstream inter-unit channel set for the bearer is set, while the terminal channel group is set as a frequency channel group different from both the downstream inter-unit channel and the upstream inter-unit channel. For example, when focusing on the wireless communication unit 1(B), the EPC function unit 3 of the wireless communication unit 1(B) selects the channel between upstream units set for the wireless bearer 55(B) between upstream units. For example, it is set to CH2. 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)). The channel between the upstream units (which is the channel between the downstream units when viewed from the wireless communication unit 1(B)) set for the radio bearer) is set to CH1, which is different from CH2. At this time, by setting the downstream inter-unit channel CH1 and the upstream inter-unit channel CH2 as mutually different frequency channels within the same band, the radio base station section 4 and the relay radio communication section 9 for constructing the inter-unit radio bearer There is an advantage that the 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.

In this case, in a row of a plurality of wireless communication units 1 sequentially cascade-connected as shown in FIG. Regarding the communication units 1(A) to 1(D), it is desirable to set the inter-unit channels of the inter-unit radio bearers 55(A) to 55(C) that connect them to all different frequency channels. On the other hand, when another wireless communication unit is connected upstream or downstream of the wireless communication units 1(A) to 1(D) whose connection path length is within the limit distance L, the other wireless communication unit It is also possible to set the inter-unit channel of the inter-unit radio bearer that connects the radio communication units to the same frequency channel as any of the inter-unit channels allocated to the radio communication units within the limit distance L described above. For example, in FIG. 11, when a new wireless communication unit is to be connected further upstream of the wireless communication unit 1(A), the distance between the upstream units of the wireless communication unit 1(A) that is farthest from the new wireless communication unit The same frequency channel CH1 as the channel can be set as the downstream inter-unit channel of the new wireless communication unit.

Further, in this embodiment, the band 28 defined by 3GPP is adopted as the same band. Band 28 is set to the VHF band (700 MHz band) 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, as a specific method for differentiating the inter-unit channel settings of the adjacent inter-unit radio bearers 55(A) to 55(C) as shown in FIG. The wireless communication units 1(A) to 1(D) can share inter-unit channel information via inter-radio bearers 55(A) to 55(C).

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. In the channel map 305g, the number of wireless communication units 1 participating in the system construction is four, and node addresses MID01 to MID04 are assigned respectively. Then, according to the combination of these node addresses, the channel numbers of the inter-unit channels set between the corresponding wireless communication units 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. In 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 acquired 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. In B104, the available channel numbers (Ch#U1, Ch#U2, . . . ) are reported 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 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 TS11, the UE5 issues an attach request to the MME2 via the 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) cascaded by an inter-unit wireless bearer 55 is connected to each wireless communication unit 1(A). The node addresses (node identification information) of the UEs 5(A) to 5(D) (mobile terminals) connected to the radio base station unit 4 of 1(D) are transferred to the inter-unit radio bearers 55(A) to 55(C). can be transferred to other wireless communication units via As a result, between the wireless communication units 1(A) to 1(D) of the node addresses of the UEs 5(A) to 5(D) being connected between two or more wireless communication units 1(A) to 1(D) It is possible to share with Then, the EPC function unit 3 creates an IP packet forwarding table based on the shared node address (node specifying information), and refers to the forwarding table to perform IP packet forwarding control.

FIG. 16 shows an example of the transfer table. The forwarding table lists node addresses (UEAD11, 12 . . . UEAD21, 22 . 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 (so-called next hopping) are stored in association with each other. In the wireless network system of the present embodiment, the next hopping information indicates that the wireless communication unit to which the UE that is the final packet transmission destination is connected performs next hopping to the adjacent wireless communication unit on the lower side of itself. , and the lower-level wireless communication unit receiving this notifies the lower-level wireless communication units in the same way, so that the next hopping information for each wireless communication unit is the packet transmission source wireless communication unit. is transmitted sequentially until 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 Transfer is performed smoothly (so-called dynamic routing method). In this embodiment, the routing table 305ert shares and stores not only the next hopping but also the addresses of the wireless communication units on the intermediate route, but this may be omitted.

FIG. 17 shows the flow of the forwarding table update process performed by each EPC function unit 3. When the process starts at A201, the arrangement (order and number) of the wireless communication units changes at A202. check whether it has been done. Specifically, it is checked whether the node address of the upstream unit or the downstream unit has changed due to a connection change described later. If the node address has changed, the process proceeds to A203. The node address of the next-hopping wireless communication unit is changed for each node address of the unit. 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 obtained. At A205, the content of the connected node registration unit 305f 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 IP packet transmission processing between UEs 5 (UE(I) and UE(II)) connected to the same wireless communication unit 1 . U1 and U2 are the attach sequences already explained with reference to FIG. 15, and 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 node registration unit 305f of FIG. Check if it matches the destination address. In the case of FIG. 18, 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. 19 shows IP packet transmission processing 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 of The processing from U1 to U3 is the same as in FIG. In U3, the EPC function unit 3 of the wireless communication unit 1(A) refers to the connected node registration unit 305f, and the destination address of the received IP packet is any of the addresses connected to the wireless communication unit 1(A) to which it belongs. 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 node registration section 305f, 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 IP packet transmission source UE is connected to an intermediate group of cascaded wireless communication units, and the transmission destination UE is connected to a wireless communication unit downstream of the wireless communication unit. If it is a UE, the EPC function unit 3 in the UE refers to the connected node registration unit 305f, 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. It also confirms that the next hopping is the wireless communication unit on the downstream side by referring to the routing table 305ert without matching the address. 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. 20 shows IP packets between UE 5 (A) connected to wireless communication unit 1 (A) and UE 5 (C) connected to wireless communication unit 1 (C) two 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 node registration unit 305f, and the destination address recorded in the header of the received IP packet is registered to the wireless communication unit 1(B) to which it belongs. ), and U5 transfers the IP packet to the upstream wireless communication unit 1(C) via the unit-to-unit wireless bearer 55(B). The wireless communication unit 1 (C) receives this IP packet, similarly refers to the connected node registration section 305f, and confirms that the IP address of the UE 5 (C) matches the IP address of the destination. 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.

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

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

It should be noted that the IP packet transfer control process in each wireless communication unit may employ a simpler method using a connected node registration unit instead of the transfer table shown in FIG. FIG. 23 shows an example of this, and only the node identification information of UE 5 currently connected to the wireless communication unit 1 provided with the connected node registration section 305f is stored as a list. The node identification information is the IP address (UEIP01, UEIP02, . identity module) Card IDs (=UE 5 terminal subscriber information: SIMID01, SIMID02, . . . ) and device MAC addresses (MAD01, MAD02, .

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

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

Unlike the method using the forwarding table of FIG. 16, the method using the connected node registration unit 305f has the advantage of not requiring communication processing that cooperates with other wireless communication units for dynamic routing. In other words, each wireless communication unit should concentrate on the process of grasping the state of its own connected UE. FIG. 24 shows the flow of the process. When the process starts at A101, it is checked at A102 whether or not there is an attach request from a new UE. If there is an attach request, the process proceeds to A103, and the node identification information of the corresponding UE is newly registered, while if there is no attach request, A103 is skipped. Next, in A104, it is checked whether there is a disconnected UE. If there is a disconnected UE, the process proceeds to A105, and the node identification information of the corresponding UE is deleted, while if there is no disconnected UE, A105 is skipped.

For example, when focusing on the wireless communication unit 1 (B) in FIG. 11, the relay wireless communication unit 9 transmits the IP packet transferred from the EPC function unit 3 to the upstream side via the upstream inter-unit wireless bearer 55 (B). is transferred as an upstream packet to the radio base station section 4 (upstream radio base station section) of the radio communication unit 1 (C). On the other hand, the radio base station section 4 of the radio communication unit 1(B) transfers the IP packet transferred from the EPC function section 3 to the downstream side radio communication unit 1(A) via the downstream inter-unit radio bearer 55(A). It is transferred as a downstream packet to the radio base station section 4 (downstream radio base station section). By performing this processing in each of the wireless communication units 1(A) to 1(D), when the destination UE exists in the wireless network system, the destination of the IP packet to be transmitted is the uplink It can always be specified in either the link or the downlink. On the side of the uplink and downlink where the destination of the IP packet to be transmitted does not exist, the IP packet reaches the wireless communication unit at the end of the link. If the previous UE cannot be found, the wireless communication unit may perform processing to invalidate (for example, discard) the IP packet.

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

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.

Hereinafter, as shown in FIG. 11, a plurality of wireless communication units 1(A) to 1(D) are connected by inter-unit wireless bearers 55(A) to 55(B) to construct the wireless network system of the present invention. , a specific example of changing the topology of the wireless communication unit connection in the system will be described.

In state A1 of FIG. 25, three wireless communication units 1(B) to 1(D) are connected by inter-unit wireless bearers 55(B) and 55(C), and the leading wireless communication unit 1(B) ), a new wireless communication unit 1(A) is approaching. When the relay wireless communication unit (BTC) 9 enters the range of the eNodeB 4 of the wireless communication unit 1(B), the relay wireless communication unit (BTC) 9 sends an attach request to the eNodeB 4 of the wireless communication unit 1(B). output to. Below, the attach sequence already explained with reference to FIG. 14 is executed, and the unit-to-unit radio bearer 55 (A) is constructed 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.

In state B1 of FIG. 26, 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. Then, when the relay wireless communication unit (BTC) 9 of the wireless communication unit 1(C) enters the range of the eNodeB 4 of the approaching wireless communication unit 1(D), the relay wireless communication unit of the wireless communication unit 1(C) 9 outputs an attach request to the eNodeB 4 of the wireless communication unit 1 (D). Below, the attach sequence already explained with reference to FIG. 14 is executed, and the unit-to-unit radio bearer 55(C) is constructed between the radio communication unit 1(C) and the radio communication unit 1(D) as in state B2. Then, the wireless communication unit 1(D) is incorporated into the wireless network system.

In both FIGS. 25 and 26, the newly added radio communication unit is the head or end of the constructed radio communication network system, that is, the radio communication unit that constitutes the edge of the network. 1(B), and FIG. 26 shows an embodiment in which connection is permitted only to reference numeral 1(C)). 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 a new wireless communication unit is rather poor.

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. 27 shows, as the simplest case, a wireless communication unit 1(C) positioned 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 wireless communication unit 1(C) is separated as described above, the quality of communication between the upstream unit (wireless communication unit 1(D) in FIG. 27) and the wireless communication unit 1(C) deteriorates. The connection of the inter-unit radio bearer 55(C) is disconnected. As a result, the wireless network system 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. 27 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. Further, when another wireless communication unit outside the network approaches a wireless communication unit in the middle of 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 A new inter-unit radio bearer must be re-established between the radio base station section of the radio communication unit to be used. If this inter-unit radio bearer disconnection can be forcibly executed by an instruction from the EPC function section from the upstream radio communication unit side according to the situation, the radio communication unit can It is possible to easily optimize the connection topology between them. 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. 28 and 29. FIG. In state D1 of FIG. 28, three wireless communication units 1(A) to 1(C) are connected by inter-unit wireless bearers 5(A) and 55(B). Towards the middle of (C), a new wireless communication unit 1 (D) is approaching. In this situation, for example, the downstream unit wireless bearer forced disconnection instruction unit of the wireless communication unit 1(C) acquires downstream unit distance information reflecting the distance d1 to the downstream unit 1(B) being connected (downstream unit distance information acquisition unit), and acquires switching candidate unit distance information reflecting the distance dc from the wireless communication unit 1(D) that is a switching candidate unit (switching candidate unit distance information acquisition unit). In state D1, d1>dc.

Then, as in state D2, the distance d1 to the switching candidate unit reflected in the acquired switching candidate unit distance information becomes smaller than the distance dc to the downstream unit reflected in the acquired downstream unit distance information. In this case, the EPC function section 3 of the radio communication unit 1(C) instructs the radio base station section 4 to temporarily and forcibly disconnect the radio bearer between downstream units (55(B)). 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 communication density of the bearer can be greatly enhanced.

The method of acquiring the downstream unit distance information and the switching candidate unit distance information can be selected from various forms and adopted. An acquisition unit is provided, and the downstream unit distance information acquisition unit and the switching candidate unit distance information acquisition unit acquire the respective current positions from the downstream unit and the switching candidate unit, and determine the distance from the downstream unit based on the information of their current positions. and the distance to the switching 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 (D) can acquire the location information of the downstream unit 1 (C) 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. 34 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 D1), it is the EPC function section 3 of the wireless communication unit 1 (D) that performs the processing. In C201, it 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 C202, the location information of the downstream unit 1 (B) (FIG. 28) that is receiving the connection is acquired via the inter-unit radio bearer 55 (B), and the distance dc is calculated based on the location information of itself. Calculate.

Then, in C203, the position information of the surrounding switching candidate unit (wireless communication unit 1(D) in FIG. 23) is acquired via the external network 60 (FIG. 3). In C204, the distance to each switching candidate unit is calculated, and the closest one is identified as d1. Then, in C205, if d1<dc, the process proceeds to C206 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. Then, if the process is not finished in C207, the process returns to C201, 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, the relay wireless communication section 9 of the old downstream unit 1(B), which has been edged by this disconnection, executes the upstream unit connection switching control program 905b. According to (FIG. 3: upstream unit connection switching control section), as in state D3, the old upstream unit 1 (C), which is a wireless communication unit connected as an upstream unit by the wireless bearer between upstream units 55 (B), Communication quality evaluation is performed with respect to each switching candidate unit 1 (D), and a process of determining a wireless communication unit to be connected as a new upstream unit based on the result of the communication quality evaluation 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. 33 shows an example of the flow of upstream unit connection switching control processing. In FIG. 28 (state D3), it is the relay wireless communication section 9 of the wireless communication unit 1 (B) that constitutes the former downstream unit that performs the processing. In C101, disconnection of the wireless bearer between units on the upstream side is detected, and if detected, the process proceeds to C102. 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. Then, 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. 33, at C102, it is confirmed whether or not the CQI reference signal is received. If received, the process proceeds to C103 to determine whether or not CQI reference signals are received from a plurality of nodes. 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, by being closest to the wireless communication unit 1(B), an attach request is made to the wireless communication unit 1(D) that has the best coding rate and frequency utilization efficiency reflected in the CQI information (see FIG. 32). Thus, an inter-unit radio bearer 55 (B') is established with the radio communication unit 1 (D). On the other hand, if the CQI reference signal is not received from multiple nodes in C103, that is, if the CQI reference signal is received only from one node (radio communication unit), proceed to C106, regardless of the CQI measurement result. Make an attach request. If the process is not finished in C107, the process returns to C101, and the following processes are repeated.

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

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 content of the downstream unit-to-unit wireless bearer forced disconnection processing is not limited to the above. For example, as shown in states E1 and E2 in FIG. can be configured to be periodically output at predetermined time intervals. 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. In FIG. 30, all the downstream unit-to-unit wireless bearers (55(A), 55(B)) are disconnected all at once, but as shown in FIG. It is also possible to shift the cycle for each wireless communication unit. In FIG. 31, state F0 indicates a state in which no downstream unit-to-unit radio bearer is disconnected, and states F1 to F3 indicate states in which any downstream unit-to-unit radio bearer is disconnected. In states F1-F3, the downstream inter-unit radio bearers to be disconnected are different from each other.

FIG. 35 shows an example of the flow of processing in that case. At C301, for example, the clock information of the disconnection scheduler incorporated in the network adjustment program 305h is referred to. In C302, it is checked whether or not a predetermined disconnection time has come. If it has arrived, the process advances to C303 to perform processing for temporarily disconnecting from the connected wireless communication unit. If the disconnection time has not come in C302, C303 is skipped. If the process is not finished in C304, the process returns to C301, and the following processes are repeated.

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, 305f' connected node registration unit 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 (9)

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 relay radio communication unit 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 relay wireless communication unit receives an upstream unit-to-unit wireless bearer setting request issued by an EPC function unit (hereinafter referred to as an upstream EPC function unit) of the upstream unit, receives the upstream unit-to-unit wireless bearer setting request, and receives the upstream unit-to-unit wireless bearer setting request. builds a radio bearer between the upstream units together with the radio base station,
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. Yes, and
The relay wireless communication unit constructs the upstream unit-to-unit wireless bearer for the wireless base station unit of the upstream unit candidate when detecting a candidate for the upstream unit to be a new connection destination while the upstream unit is not connected. By transmitting an attach request to establish a radio bearer between upstream units, the upstream unit radio bearer construction control section receives the radio bearer setting request between upstream units from the upstream unit candidate and controls construction of the radio bearer between upstream units. while being prepared,
When the wireless base station section receives an attach request from a downstream unit candidate to be newly connected while the downstream unit is not connected, the wireless base station section notifies the EPC function section of the attach request. an inter-downstream unit radio bearer construction control unit that receives the terminal radio bearer setting request from the unit and performs control for constructing the inter-downstream unit radio bearer ,
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. It has an upstream unit connection switching control unit that switches connection to the 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. performing communication quality evaluation for each unit, and determining a wireless communication unit to be connected as a new upstream unit based on the result of the communication quality evaluation;
The upstream unit connection switching control section receives a CQI reference signal from each wireless communication unit, generates CQI information using the CQI reference signal, and performs the communication quality evaluation based on the content of the CQI information. A wireless communication unit characterized by: 2. The wireless communication according to claim 1 , wherein the upstream unit connection switching control section switches connection to the switching candidate unit when the connection with the upstream unit is cut due to deterioration of communication quality with the upstream unit. unit. 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 downstream unit that is being connected, and a switching unit that reflects the distance to the switching candidate unit. A distance d1 between a switching candidate unit distance information acquisition unit that acquires candidate unit distance information and the switching candidate unit reflected in the acquired switching candidate unit distance information is reflected in the acquired downstream unit distance information. 3. The wireless communication unit according to claim 1 , wherein an instruction to temporarily and forcibly disconnect the wireless bearer between downstream units is issued when the distance becomes smaller than the distance dc from the downstream unit. 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. 4. The radio communication unit according to claim 3 , wherein the distance to the previous downstream unit and the distance to the switching candidate unit are calculated based on the information of their current positions. 2. The wireless communication unit according to claim 1 , wherein the downstream unit-to-unit wireless bearer forced disconnection instruction unit periodically outputs an instruction to disconnect the downstream unit-to-unit wireless bearer at predetermined time intervals. The EPC function unit controls the relay radio communication units of the plurality of mobile terminals and other radio communication units that are connected to the radio base station via the terminal radio bearer within the communication area of the radio base station unit. , a connected node registration unit for registering node identification information of the mobile terminals being connected, and comparing the destination node of the IP packet transferred from the radio base station unit with the registered contents of the connected node registration unit. , when the destination node indicates a mobile terminal corresponding to any of the node identification information registered in the connected node registration section, the IP packet is returned to the mobile terminal by the radio base station section. on the other hand, when the destination node indicates a node not registered in the connected node registration unit, the IP packet is transferred from at least one of the relay wireless communication unit and the wireless base station unit to the wireless communication unit 6. The wireless communication unit according to any one of claims 1 to 5 , wherein control is performed to transfer to an external destination. A radio base station unit configured to be mountable on a mobile body and for performing radio network communication with a mobile terminal, the radio base station section to which the mobile terminal can be connected via a terminal radio bearer; an EPC (Evolved Packet Core) function unit connected by wire to a radio base station unit and functioning as an upper network control unit for the radio base station unit; and a first separate radio communication unit connected by wire to the EPC function unit a radio base station section of an upstream unit (hereinafter referred to as an upstream radio base station section) and a relay radio communication section connectable via an upstream inter-unit radio bearer (hereinafter referred to as an upstream inter-unit radio bearer); The base station section connects the relay wireless communication section of the downstream unit, which is a second separate wireless communication unit (hereinafter referred to as the downstream relay wireless communication section), and the downstream inter-unit wireless bearer (hereinafter referred to as the downstream inter-unit wireless bearer). 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 the downstream relay wireless communication. The EPC function unit transmits a terminal radio bearer setting request to the radio base station unit, while the radio base station unit receives the terminal radio bearer setting request. The relay wireless communication unit receives an upstream unit-to-unit wireless bearer setting request issued by an EPC function unit of the upstream unit (hereinafter referred to as an upstream EPC function unit). and constructs the upstream inter-unit radio bearer together with the upstream radio base station section in response to the upstream unit radio bearer setting request, and the EPC function section transmits the terminal radio bearer setting request to the radio base station section , the radio base station section receives the terminal radio bearer setup request and constructs the terminal radio bearer together with the mobile terminal, and further, the relay radio communication section receives the terminal radio bearer setting request, and further, the relay radio communication section receives the terminal radio bearer setting request, When a candidate for an upstream unit to be a new connection destination is detected in the state of (1), by transmitting an attach request for constructing the radio bearer between the upstream units to the radio base station section of the candidate for the upstream unit, and an upstream unit-to-unit radio bearer construction control section that receives the upstream unit-to-unit radio bearer setup request from the upstream unit candidate and controls to construct the upstream unit-to-unit radio bearer. receives an attach request from a downstream unit candidate to be newly connected in a non-connected state, notifies the attach request to the EPC function unit, and sets the radio bearer for the terminal from the EPC function unit. comprising a wireless communication unit group in which a plurality of wireless communication units having an inter-downstream unit radio bearer construction control section that receives a request and controls construction of the inter-downstream unit radio bearer;
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. and
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. It has an upstream unit connection switching control unit that switches connection to the unit,
In each said wireless communication 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. performing communication quality evaluation for each unit, and determining a wireless communication unit to be connected as a new upstream unit based on the result of the communication quality evaluation;
The upstream unit connection switching control section receives a CQI reference signal from each wireless communication unit, generates CQI information using the CQI reference signal, and performs the communication quality evaluation based on the content of the CQI information. A wireless network system characterized by : 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 unit. a connected node registration unit for registering node identification information of the mobile terminal being connected to the relay radio communication unit of the mobile terminal and the other radio communication unit of the IP packet transferred from the radio base station unit is collated with the registered contents of the connecting node registration unit, and if the destination node indicates a mobile terminal corresponding to any of the node identification information registered in the connecting node registration unit forwarding the IP packet to the mobile terminal by looping it back at the radio base station unit, and relaying the IP packet when the destination node indicates a node not registered in the connected node registration unit; 8. The wireless network system according to claim 7 , wherein control is performed to transfer data from at least one of the wireless communication unit and the wireless base station unit to a destination outside the wireless communication unit. The EPC function unit creates a transfer table for the IP packet based on the shared node identification information of the relay wireless communication unit, refers to the transfer table, and controls transfer of the IP packet, 9. The wireless network system according to claim 8 , wherein the contents of said forwarding table are updated when the number of said wireless communication units included in said wireless network system is increased or decreased and when the order of connection is changed.

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