JP7545248B2 - Wireless communication unit and wireless network system using the same - Google Patents

Description

This invention relates to a wireless communication unit for performing wireless network communication with a mobile terminal in accordance with a communication protocol stack defined by 3GPP (Third Generation Partnership Project), and to a wireless communication unit that can easily realize coordinated operation between multiple units and can be suitably used for covering a wide area, and a wireless network system that uses the wireless communication unit.

In wireless network systems based on high-speed communication standards based on 3GPP specifications (for example, LTE (Long Term Evolution) or WiMAX (Worldwide Interoperability for Microwave Access)), it is essential to construct an EPC (Evolved Packet Core) that accommodates a wireless communication access network within the area, and wireless base stations to which mobile terminals connect are controlled for sending and receiving IP packets via the EPC. On the other hand, with the spread of mobile terminals such as mobile phones, smartphones, and tablet PCs, there is an increasing demand to use mobile terminals in areas where the infrastructure of EPCs and wireless base stations is not in place, such as at sea, in depopulated areas, or in areas where communication functions have been lost due to disasters, etc. (hereinafter referred to as "wireless undeveloped areas").

In order to meet such demands, for example, Patent Document 1 proposes a combined wireless communication unit that integrates a wireless base station and an EPC function unit. By installing such a wireless communication unit in a wireless non-equipped area as described above, a small communication area is created by the wireless base station unit included in the unit, and wireless communication can be performed between multiple mobile terminals connected to the wireless base station unit by controlling communication with the EPC function unit in the unit. However, the communication area that can be covered by one wireless communication unit is narrow, and the communication capacity is also limited. In this case, it is possible to place multiple wireless communication units in the wireless non-equipped area, but there is a drawback that communication cooperation between the units is not taken into consideration, and mobile terminals connected to different composite devices cannot communicate with each other. In addition, there is a problem that congestion and other problems are likely to occur when communication traffic in the area becomes excessive, such as when the number of connected mobile terminals increases or when large amounts of data such as video data are sent and received.

Patent documents 2 to 7 disclose configurations in which multiple wireless communication units are linked together, and communication traffic from a mobile terminal is distributed to each wireless communication unit for forwarding processing. Specifically, FIG. 6 of patent document 5 discloses a form in which a satellite device is used as a linking path between wireless communication units to offload communication with a mobile terminal.

JP 2016-12841 A 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 show how multiple wireless communication units are interconnected (for example, FIG. 1 of Patent document 2). However, apart from the off-load form via the satellite device described above, the above documents do not disclose how the connection is actually constructed. If it is assumed that the wireless communication units are connected by wire, the communication cables connecting the devices would become very long if the wireless communication units were to be distributed in a reasonably wide communication area in a wireless non-developed area. As a result, signal quality and communication capacity would be reduced, and relay devices would be required to prevent this, resulting in a problem of rising costs for building connection infrastructure. Furthermore, in applications where wireless communication units are mounted on moving objects such as trains, automobiles, and ships, it is physically impossible to connect each wireless communication unit by cable.

The object of the present invention is to provide a wireless communication unit that can wirelessly link multiple wireless communication units with a simple structure, and thus can easily realize linked operations between multiple units, and a wireless network system using the same.

In order to solve the above problems, the wireless communication unit of the present invention is a wireless communication unit for performing wireless network communication with a mobile terminal according to a communication protocol stack defined by 3GPP (Third Generation Partnership Project), and includes a wireless base station unit to which the mobile terminal can be connected via a terminal wireless bearer, and an Evolved Packet Control (EPC) unit that is wired connected to the wireless base station unit and functions as a higher-level network controller for the wireless base station unit. The wireless communication unit includes a wireless base station unit (hereinafter referred to as an upstream wireless base station unit) of an upstream node unit, which is another wireless communication unit on the upstream side, attached to the wireless base station unit so as to be able to establish an association connection with the upstream node unit via an upstream association wireless bearer (hereinafter referred to as an upstream wireless link). The wireless base station unit is attached to a downstream node unit, which is another wireless communication unit on the downstream side, attached to the downstream relay wireless communication unit (hereinafter referred to as a downstream relay wireless communication unit). The EPC functional unit includes a communication firmware storage unit that stores communication firmware incorporating a communication protocol stack, and a communication firmware storage unit that stores a communication firmware by executing the communication firmware. and a communication control unit that controls wireless network communications through the wireless link. A wireless link protocol layer is added as a new protocol layer on the upper layer side of the transport layer on the control plane side of the communication protocol stack, which handles the transmission and reception of linkage notification information, which is notification information used to control the construction and management of a linkage radio bearer between the EPC control unit of the upstream node unit or between the EPC control unit of the downstream node unit. The communication control unit incorporates linkage notification information into a linkage notification packet defined on the wireless link protocol layer, and is characterized by having a linkage notification information transmission and reception control unit that executes the transmission and reception control of the linkage notification information between the upstream node unit or the downstream node unit as the transmission and reception control of the linkage notification packet based on the packet transmission and reception protocol defined on the transport layer.

The wireless network system of the present invention is a wireless communication unit for performing wireless network communication with a mobile terminal according to a communication protocol stack defined by 3GPP (Third Generation Partnership Project), and includes a wireless base station unit to which the mobile terminal can connect via a terminal wireless bearer, and an EPC (Evolved Packet Control Protocol) that is wired to the wireless base station unit and functions as a higher-level network control unit for the wireless base station unit. The wireless communication unit includes a wireless base station unit (upstream wireless base station unit) of an upstream node unit, which is another wireless communication unit on the downstream side, attached to the wireless base station unit (downstream wireless base station unit) of the downstream node unit, which is another wireless communication unit on the downstream side, and is capable of an associated connection with the upstream node unit via an associated wireless bearer (upstream wireless link). The wireless base station unit is capable of an associated connection with the downstream node unit via the associated wireless bearer (downstream wireless link) on the downstream side by receiving an attachment from the relay wireless communication unit (downstream relay wireless communication unit) of the downstream node unit, which is another wireless communication unit on the downstream side. The EPC functional unit includes a communication firmware storage unit that stores communication firmware incorporating a communication protocol stack, and a communication control unit that performs wireless network communication control by executing the communication firmware. The associated wireless bearer is connected between the EPC control unit of the upstream node unit or the EPC control unit of the downstream node unit as a new protocol layer on the upper layer side of the transport layer on the control plane side of the communication protocol stack. A wireless communication unit equipped with a wireless communication information transmission/reception control unit that incorporates the cooperation notification information into a cooperation notification packet defined on the wireless cooperation protocol layer and controls the transmission and reception of the cooperation notification information between an upstream node unit or a downstream node unit as transmission and reception control of the cooperation notification packet in accordance with a packet transmission and reception protocol defined on the transport layer is characterized in that the wireless communication unit comprises a group of wireless communication units mutually connected by a cooperation wireless bearer, and a mobile terminal connected via a terminal wireless bearer to a first wireless communication unit constituting any one of the plurality of wireless communication units, and a mobile terminal connected via a terminal wireless bearer to a second wireless communication unit constituting any one of the other units, transmit and receive user data via two or more wireless communication units extending from the first wireless communication unit to the second wireless communication unit and the cooperation wireless bearer that connects these wireless communication units to each other. The only difference between an upstream wireless link and a downstream wireless link is whether they are constructed on the upstream side or downstream side of the wireless communication unit in question. The functional entity of the associated wireless bearer that interconnects the relay wireless communication unit and the wireless base station unit of adjacent wireless communication units is the same, and hereinafter, when referring to these collectively, they are also referred to simply as "wireless links."

The wireless communication unit of the present invention is provided with a relay wireless communication unit that can be connected to a wireless base station unit (upstream wireless base station unit) of an upstream node unit via an upstream wireless link. In addition, the wireless base station unit can be connected to a relay wireless communication unit (downstream relay wireless communication unit) of a downstream node unit via a downstream wireless link.

In other words, the relay wireless communication unit of a wireless communication unit can wirelessly connect to the wireless base station of another wireless communication unit. As a result, multiple wireless communication units can be linked via wireless links, and the wireless communication area for mobile terminals can be expanded. In addition, the control plane side of the communication protocol stack has a unique configuration in which a new protocol layer, the wireless linking protocol layer, is added to the upper layer of the transport layer. By incorporating linking notification information used to control the construction and management of wireless links (linking wireless bearers) into linking notification packets defined on the wireless linking protocol layer, the form of control of sending and receiving linking notification information between multiple wireless communication units that are targets of linking can be greatly simplified, and control programming can be simplified. As a result, linking connection control via wireless links between wireless communication units can be performed in a fine-grained manner.

1 is a schematic diagram showing the concept of a wireless communication unit pair that is a constituent unit of a wireless network system of the present invention; 2 is a block diagram showing an outline of the electrical configuration of the wireless communication unit pair of FIG. 1; FIG. 2 is a block diagram showing an example of an electrical configuration of a wireless communication unit according to the present invention. FIG. 2 is a block diagram showing an example of the electrical configuration of a UE (mobile terminal). 1 is a conceptual diagram illustrating a structure of a general IP packet in comparison with a structure of an association broadcast packet. FIG. 2 is a diagram conceptually showing a protocol stack on the control plane side used in the present invention. FIG. 13 is a conceptual diagram showing the protocol stack on the user plane side. FIG. 2 is a diagram conceptually showing downlink channel mapping used in the present invention. FIG. 13 is a diagram conceptually showing uplink channel mapping. FIG. 1 is a conceptual diagram showing the relationship between frequency band channels and resource blocks. FIG. 1 is a diagram illustrating an example of a configuration of a wireless network system according to the present invention. A conceptual diagram of a channel map. 12 is a diagram showing the contents of a routing management table of each node unit in the wireless network system of FIG. 11 . FIG. 11 is a communication flow diagram showing the flow of a process of updating the routing management table of each node unit using a cooperation notification packet. 14B is a communication flow diagram following FIG. 14A. FIG. 11 is a communication flow diagram showing the flow of a process of updating wireless connection topology information in each node unit using an association notification packet. 11 is a communication flow diagram showing an attachment sequence of a relay wireless communication section of a wireless communication unit to another wireless communication unit on the upstream side; 1 is a communication flow diagram illustrating an attach sequence of a UE (Mobile Terminal) to a wireless communication unit. FIG. 1 is a communication flow diagram showing an IP packet transfer control sequence between UEs connected to the same wireless communication unit. FIG. 1 is a communication flow diagram showing an IP packet transfer control sequence between UEs each connected to adjacent wireless communication units. FIG. 11 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. 11 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 located at the end of three cascade-connected wireless communication units. FIG. 11 is a communication flow diagram showing a process of determining whether to permit establishment of an associated radio bearer by using a temporary radio link (in the case of non-permission). FIG. 11 is a communication flow diagram showing a process of determining whether to permit establishment of an associated radio bearer by using a provisional radio link (in the case of permission). 11 is a communication flow showing the flow of a process for rejecting attachment to a candidate unit using a rejection list (connection-disallowed unit registration section).

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
1 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, as one embodiment. The wireless communication unit pair is composed of wireless communication units 1(A) and 1(B) having the same configuration as one embodiment of the present invention (hereinafter, also referred to as wireless communication unit pair 1(A) and 1(B)), and is configured to perform wireless communication with a UE (mobile terminal) 5 according to a communication protocol stack of a method defined by 3GPP (LTE in this embodiment, but other methods such as WiMAX may also be used).

The wireless communication units 1(A) and 1(B) are installed on large ships WS(A) and WS(B), which are mobile bodies, and are wirelessly connected by a wireless link 55, which will be described in detail later. Each wireless communication unit 1(A) and 1(B) forms a cell 50(A) and 50(B), to which a UE (mobile terminal) 5 can connect. Small vessels FB (e.g., fishing boats, tugboats, etc.) are operating around the large vessels WS(A) and WS(B) (e.g., fishing mother ships, tankers, etc.), and crew members of the small vessels FB in the cell 50(A) or cell 50(B) carry UE5. The UE5 is wirelessly connected to the nearest wireless communication units 1(A) and 1(B) by a terminal wireless bearer 57. The UE5 may be carried by the crew members of the large vessels WS(A) and WS(B). Furthermore, the wireless communication units 1(A) and 1(B) may be installed on a moving body (such as a vehicle) other than a ship, or may be fixedly installed at a desired location on land, for example.

Figure 2 shows the functional block configuration of the wireless communication units 1 (A) and 1 (B). Both wireless communication units 1 (A) and 1 (B) have the same electrical configuration. In this specification, when multiple wireless communication units and their components are to be distinguished from one another, the corresponding components are given the same numbers, and capital letters in parentheses are added following the numbers. On the other hand, when each component is to be shown without distinguishing between wireless communication units, the capital letters in parentheses may be omitted. In the following, the symbols on the wireless communication unit 1 (A) side are mainly used for the explanation, but the wireless communication unit 1 (B) side will also be explained using the corresponding symbols as necessary. In addition, in the drawings attached to this specification, the arrows indicating the wireless bearers are shown with dashed lines, and the wired bearers or electrical connection lines are shown with solid or dashed arrows.

The wireless communication unit 1(A) has a wireless base station unit 4(A) (eNodeB (evolved NodeB)) to which a UE (mobile terminal) 5 can be connected via a terminal wireless bearer 57, and an EPC (Evolved Packet Core) functional unit 3(A) that is wired-connected to the wireless base station unit 4(A) and functions as a higher-level network control unit for the wireless base station unit 4(A). In addition, a relay wireless communication unit 9(A) that can be connected to the wireless base station unit 4(B) (upstream wireless base station unit) of the upstream wireless communication unit 1(B) (upstream node unit) via an upstream associated wireless bearer (upstream wireless link) 55(A) is wired-connected to the EPC functional unit 3(A).

On the other hand, the wireless communication unit 1(B) includes a similar wireless base station unit 4(B), an EPC function unit 3(B) that is wired to the wireless base station unit 4(B) and functions as a higher-level network control unit for the wireless base station unit 4(B), and a relay wireless communication unit 9(B) that is wired to the EPC function unit 3(B). If another wireless communication unit (upstream node unit) 1(C) is arranged upstream of the wireless communication unit 1(B), the relay wireless communication unit 9(B) can be connected to the wireless base station unit 4(C) of the wireless communication unit 1(C) via a wireless link 55(B) (see FIG. 11), as shown in FIG. 11 for example. In addition, the wireless base station unit 4(B) can be connected to the relay wireless communication unit 9(A) (downstream relay wireless communication unit) of the downstream wireless communication unit 1(A) (downstream node unit) via a downstream associated wireless bearer (downstream wireless link) 55(A). For example, wireless link 55(A) is an upstream wireless link when viewed from wireless communication unit 1(A) and is a downstream wireless link when viewed from wireless communication unit 1(B).

Next, in both wireless communication units 1(A) and 1(B) (hereinafter collectively referred to as wireless communication unit 1), the EPC function unit 3 has an MME (Mobility Management Entity) 2 which serves as a gateway on the control plane side, an S-GW (Serving Gateway) 6 which serves as a gateway on the user plane side, the EPC function unit 3, and a P-GW (PDN (Packet Data Network) Gateway) 7 which is located at the junction of the upstream network elements of the EPC function unit 3 (here, a router 8 (described later) and a relay wireless communication unit 9) and manages IP addresses toward the upstream network elements (i.e., the upstream node unit). A plurality of UEs 5 are wirelessly connected to the wireless base station unit 4 via a terminal wireless bearer 57. In addition, an application server 8' which serves as a distribution source of user data consisting of video data, image data, or voice data is connected to the router 8.

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

Figure 3 is a block diagram showing the electrical configuration of the wireless communication unit 1. The EPC function section 3 is mainly composed of microcomputer hardware, and includes a CPU 301, a RAM 302 which serves as a program execution area, a mask ROM 303 (which stores firmware for controlling the microcomputer hardware peripherals, etc., that does not require permanent rewriting; the same applies below), and a bus 306 which interconnects them. In addition, a flash memory 305 is connected to the bus 306, which stores communication firmware 305a (a program that realizes the functions of the communication control section) including a communication protocol stack for the EPC.

Figures 6 and 7 show the communication protocol stacks used by the wireless communication unit 1, with Figure 6 showing the protocol stack on the control plane side and Figure 7 showing the co-protocol stack on the user plane side. Both protocol stacks are divided into a stack for wired communication and a stack for wireless communication, and in Figures 6 and 7, the part marked "LTE" shows the stack for wireless communication. For ease of explanation, both figures show the wireless communication unit 1 (A) and the wireless communication unit 1 (B) connected by a wireless link. The protocol stack used by the EPC function unit 3 consists of a core network side interface Core and a radio access network side interface RAN. For simplicity of explanation, in Figures 6 and 7, only the core network side interface Core is shown on the wireless communication unit 1 (A) side.

First, the protocol stack on the control plane side of FIG. 6 will be described. The wireless base station unit (eNodeB) 4 is connected to the wireless access network side interface RAN of the EPC function unit 3. The protocol stack in this section consists of a PHY (physical) layer (L1), a MAC (Medium Access Control) layer (L2) which constitutes a data link layer, an IP (Internet Protocol) layer which constitutes a network layer, a UDP (User Datagram Protocol) layer which constitutes a transport layer, and a GTP (GPRS (General Packet Radio Service) Tunneling Protocol) layer which constitutes the top layer. This connection section is wired communication within the unit, and IP packets are exchanged by tunneling using GTP. In addition, the relay wireless communication unit 9 is connected to the core network side interface Core of the EPC function unit 3, and IP packets are exchanged by LAN communication via the IP layer.

On the other hand, the protocol stack of the wireless communication section between the relay wireless communication unit 9 and the wireless base station unit (eNodeB) 4 is made up of a PHY layer, a MAC layer, an RLC layer, a PDCP layer, and an RRC layer. The roles of each layer are as follows:
PHY layer: performs encoding/decoding, modulation/demodulation, antenna mapping/demapping, and resource mapping/demapping. Data and control signals are transmitted between the PHY layers of the UE 5 and the relay wireless communication unit 9 and the PHY layer of the wireless base station unit (eNodeB) 4 via a physical channel.
MAC layer: Performs data priority control, retransmission control processing by HARQ, random access procedure, etc. Data and control signals are transmitted via transport channels between the MAC layers of the UE 5 and relay wireless communication unit 9 and the MAC layer of the wireless base station unit 4. The MAC layer of the wireless base station unit 4 includes a scheduler that determines the uplink and downlink transport formats (transport block size, modulation and coding scheme (MCS)) and the resource blocks to be assigned to the UE 5.

RLC layer: Utilizing the functions of the MAC layer and the PHY layer, data is transmitted to the RLC layer on 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 PDU header compression/decompression, and encryption/decryption.
RRC layer: Defined only in the control plane that handles control signals. Messages (RRC messages) for various settings are transmitted between the RRC layer of the UE 5 and the RRC layer of the radio base station unit 4. The RRC layer controls logical channels, transport channels, and physical channels in response to the establishment, re-establishment, and release of radio bearers. When 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, and otherwise in RRC idle mode.

Next, a cooperation radio bearer (radio link) is constructed between two wireless communication units (upstream node unit) 1 (A) and wireless communication unit (downstream node unit) 1 (B), and the control sequence for connecting them together is executed by transmitting and receiving cooperation notification information used to control the construction and management of the cooperation radio bearer between the EPC function units 3 of the upstream node unit and downstream node unit. A wireless cooperation protocol layer WLP that handles the cooperation notification information is added to the protocol stack that constitutes the core network side interface Core.

The protocol stack constituting the core network side interface Core includes, from the bottom up, the PHY layer (L1), MAC layer (L2), IP layer, UDP layer, and wireless cooperation protocol layer WLP. The wireless cooperation protocol layer WLP is defined as a new protocol layer specific to the present invention that is constructed on the UDP layer (transport layer). The above cooperation notification information is incorporated into a cooperation notification packet defined on the wireless cooperation protocol layer WLP, and the EPC function unit 3 of the upstream node unit and the downstream node unit executes the transmission and reception control of the cooperation notification information as the transmission and reception control of the cooperation notification packet based on the packet transmission and reception protocol defined on the transport layer (here, UDP) (the function of the cooperation notification information transmission and reception control unit is realized). UDP is a simple protocol that excludes states for connection confirmation and does not have a function to detect errors or differences in order of transmitted and received data. For example, in the case of TCP (Transmission Control Protocol), which is a protocol of the same transport layer, in addition to packet communication of the data body, start processing and end processing are performed, but UDP does not execute start processing and end processing. In addition, while TCP returns an ACK (acknowledgement) in response to a received packet, UDP does not return an ACK. The UDP data transmission and reception procedure is simplified in this way, which contributes to accelerating the control of the inter-unit interworking connection. The program that realizes the functions of the wireless interworking protocol layer WLP is incorporated into the communication firmware 305a in FIG. 3 as the wireless interworking protocol layer module 305p.

Next, the protocol stack on the user plane side in Figure 7 will be described. The structure of this protocol stack is in many respects the same as the stack structure on the control plane side in Figure 6, so below, we will mainly explain the differences, and the protocol layers that overlap structurally will be given the same reference numerals as in Figure 6 and will not be described in detail. The core network side interface Core of the EPC function unit 3 is dedicated to passive forwarding processing of received IP packets with respect to user data, so the topmost layer is the IP layer, which is a network layer. In addition, in the UE 5 or application server (APP) 8', which is the source and destination of user data, the topmost protocol layer that handles the transmission and reception of the user data is the application layer APP.

The top of FIG. 5 is a schematic diagram of an IP packet used to transfer user data. The IP packet 1300 is composed of an IP header 1301 and a payload 1302, and the IP header 1301 contains a PDU identification number, a data source address 1301a, a destination address 1301b, and the like. On the other hand, the bottom of the same figure is a schematic diagram of an association notification packet 1350, which is composed of an IP header 1351 and a payload 1352. The difference from an IP packet used to transfer user data is that it is issued as an IP packet with a destination address fixed to a specific address ("172.17.1.1" in the bottom of FIG. 5). This fixed destination address also serves as identification information indicating that the IP packet is an association notification packet. By using such an association notification packet 1350, the association notification information incorporated in the payload 1352 of one association notification packet can be easily shared among multiple wireless communication units that are linked and connected by wireless links.

Next, the wireless cooperation protocol layer module 305p of the communication firmware 305a includes the following three control modules.
Routing management module 305pr
The EPC function unit 3 manages the direction in which the IP packets (user data and control data) received by the wireless base station unit 4 or the wireless communication relay unit 9 are transmitted, as viewed from the EPC function unit 3. Basically, one of the following three operations is performed.
(Management control 1) Transfer the IP packet upstream, that is, in the direction toward the wireless base station unit 4 of the upstream node unit via the relay wireless communication unit 9 of the own node unit and the upstream wireless link.
(Management control 2) Transfer the IP packet downstream, that is, in the direction toward the relay wireless communication unit 9 of the downstream node unit via the wireless base station unit 4 of the own node unit and the downstream wireless link.
(Management control 3) The IP packet is transferred to the application server 8' or UE 5 connected to the own node unit.

A list of the node addresses of the application server 8' and UE 5 connected to the upstream node unit and downstream node unit is shared among all the node units (wireless communication units 1) that make up the wireless network system according to a method described in detail later, and is stored as a routing management table 305f (routing management information). The contents of this routing management table 305f are periodically updated by communication between adjacent node units via cooperation notification packets. The operation of the routing management module 305pr is reduced to a process of simply determining whether the destination address of a received IP packet is on the upstream side (management control 1), downstream side (management control 2), or within the area of the own node unit (management control 3) by referring to the routing management table 305f.

Topology management module 305pt
The wireless connection topology (topological connection form via wireless links) of all node units constituting the wireless network system is managed. The wireless connection topology can be grasped by sharing specific information of the upstream node unit and downstream node unit as seen from the own node unit among all node units (wireless communication units 1), and the contents are stored as a topology management table 305tt (topology management information). The contents of this topology management table 305tt are also periodically updated by communication between adjacent node units via cooperation notification packets. In addition, a rejection list 305rr, which will be described later, is also incorporated in the topology management module 305pt.

Radio link management module 305pj
The relay wireless communication unit 9 or the wireless base station unit 4 manages the state of the wireless link (associated wireless bearer) constructed. Specifically, when the relay wireless communication unit 9 of the own node unit is connected to the wireless base station unit 4 of the upstream node unit via the wireless link 55, or when the relay wireless communication unit 9 of the downstream node unit is connected to the wireless base station unit 4 of the own node unit via the wireless link 55, the association mode is established, and the above-mentioned routing management module 305pr and topology management module 305pt are started. On the other hand, when there is no connection of other node units via the wireless link 55, the isolation mode is established, and each content of the routing management information and the topology management information is cleared. Furthermore, a channel map 305g for determining a channel to be assigned to the wireless link 55 in the association mode is also incorporated in the wireless link management module 305pj.

Figure 11 shows an example of the configuration of the wireless network system of the present invention when the wireless communication unit 1 of the above configuration is adopted. In the wireless network system, the wireless communication unit groups 1(A) to 1(C) are connected by wireless links 55(A) and 55(B) in a positional relationship in which the base station cells (for example, 50(A) and 50(B) in Figure 1 for the wireless communication unit pair 1(A) and 1(B)) of adjacent wireless communication unit pairs (1(A) and 1(B), 1(B) and 1(C)) partially overlap. For example, UE5(A) (mobile terminal) connected to one of the wireless communication unit pair 1(A) and 1(B) and UE5(B) (mobile terminal) connected to the other can transmit and receive IP packets via the wireless communication unit pair 1(A) and 1(B) and the associated wireless bearer 55(A) that connects the wireless communication unit pair 1(A) and 1(B). For example, all of the wireless communication unit groups 1(A)-1(C) may be mounted on a moving body such as the ship mentioned above, or only some may be mounted on a moving body and the rest may be fixedly installed in a building or the like. Also, all of the wireless communication unit groups 1(A)-1(C) may be fixedly installed in areas where wireless communication networks are not deployed.

In addition, in FIG. 11, there are three (or more) wireless communication units connected by wireless links 55(A) and 55(B). For example, UE (mobile terminal) 5(A) connected to wireless communication unit 1(A) can transmit and receive IP packets via UE (mobile terminal) 5(C) connected to wireless communication unit 1(C), wireless communication units 1(A) to 1(C), and associated wireless bearers 55(A) and 55(B) connecting those wireless communication units 1(A) to 1(C). In this way, the number of connected wireless communication units can be easily increased, making it possible to transmit and receive IP packets by wireless communication between UEs 5 in a wider area.

The table shown at the bottom of FIG. 11 shows, for the wireless communication unit groups 1(A)-1(C), the communication frequency/channel number of the wireless links 55(A) and 55(B), the tracking area code, the node addresses of the connected UEs 5(A)-5(C) and application servers 8'(A)-8'(C) (for the sake of simplicity, the node addresses of the multiple UEs 5 and application servers 8' are shown as a subnetwork address), and the destination address of the association notification packet transmitted and received on the wireless association protocol layer WLP. The destination address of the association notification packet is set to be the same for each of the wireless communication units 1(A)-1(C). In addition, the node addresses of all the connected UEs 5(A)-5(C) and application servers 8'(A)-8'(C) in the entire wireless network system are shared between the wireless communication unit groups 1(A)-1(C) and are stored in the routing management table 305f in FIG. 3. The connection topology information ([A] → [B] → [C]) of the wireless communication units 1(A) to 1(C) is also shared in the same manner and stored in the topology management table 305tt. The specific information (above [A], [B], [C]) of each wireless communication unit 1(A) to 1(C) stored in the topology management table 305tt may be an ID uniquely assigned to the wireless communication unit 1(A) to 1(C), or the node address of the wireless communication unit 1(A) to 1(C) (for example, the node address of any of the EPC function unit 3, the wireless base station unit 4, and the relay wireless communication unit 9, or a unit node address assigned separately from these) may be used. In this embodiment, the node address of the EPC function unit 3 is used.

Figure 13 shows an example of the contents of the routing management table 305f, and from the top, shows the routing management tables 305f of the wireless communication units 1(A), 1(B) and 1(C) in the connected state of Figure 11. The node addresses of UEs 5(A)-5(C) and application servers 8'(A)-8'(C) are stored in a form that distinguishes between nodes on the downstream route side and nodes on the upstream route side when viewed from the own node unit.

Flash memory 305 also has installed therein programs for MME entity 305b, S-GW entity 305c, and P-GW entity 305d, which virtually realize the functions of MME2, S-GW6, and P-GW7 in FIG. 2 using the above-mentioned communication protocol stack as a platform. An upstream communication interface 304A and a downstream communication interface 304B are connected to bus 306. An input/output port for IP packets for P-GW is secured in upstream communication interface 304A, and an input/output port for IP packets for S-GW is secured in downstream communication interface 304B. In the above configuration, MME2, S-GW6, and P-GW7 in FIG. 2 are configured as virtual function blocks on computer hardware, but each may be configured with independent hardware logic.

The wireless base station unit 4 is mainly composed of microcomputer hardware, and includes a CPU 401, a RAM 402 which serves as a program execution area, a mask ROM 403, and a bus 406 which interconnects them. A flash memory 405 is connected to the bus 406, which stores communication firmware 405a including an LTE protocol stack for the wireless base station. Also connected to the bus 406 are a wireless communication unit 412 for wirelessly connecting to a UE by establishing a terminal wireless bearer, and a communication interface 404. The communication interface 404 is connected to the downstream communication interface 304B of the EPC function unit 3 by a 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 connecting them to each other. A flash memory 905 is connected to the bus 906, and communication firmware 905a including an LTE protocol stack for the relay wireless communication unit is stored in the flash memory 905. The bus 906 is also connected to a wireless communication unit 912 for wirelessly connecting to an upstream wireless base station unit by establishing a wireless link, and a communication interface 904. The communication interface 904 is connected to the upstream communication interface 304A of the EPC function unit 3 by a wired communication bus 30. The LTE protocol stack for the relay wireless communication unit incorporated in the communication firmware 905a is the same as the protocol stack for a UE (mobile terminal) described later. In other words, the connection procedure of the relay wireless communication unit 9 to the upstream wireless base station unit is the same as the connection procedure of the UE (mobile terminal).

In addition, a router 8 is connected to the communication bus 30, which relays the transmission and reception of IP packets between the EPC function unit 3 and an application server 8' (or an external network such as the Internet).

Next, the wireless communication unit 1 has a structure in which a detachable secondary battery module 21 (for example, a lithium ion secondary battery module or a nickel hydrogen secondary battery module, etc.), each functional circuit block of the wireless base station unit 4, the EPC function unit 3, the router 8, and the relay wireless communication unit 9, and a power supply circuit unit 22 that converts the input voltage from the secondary battery module 21 into a drive voltage for each functional circuit block and outputs it are integrally assembled in a portable housing 23. This allows the wireless communication unit 1 to autonomously obtain a drive power supply voltage from the secondary battery module 21, and can be used without problems even in installation locations where external power supply voltages such as commercial AC cannot be used (for example, at sea). The portable housing 23 is a box-shaped body made of metal or reinforced resin, and in the example shown in FIG. 3, casters 24C are provided on the bottom of the portable housing 23 and a handle 24 for pushing is provided on the back for ease of transportation or movement.

When the output voltage of the secondary battery module 21 drops due to discharge, the secondary battery module 21 can be removed from the portable housing 23 and charged by attaching it to a dedicated charger connected to, for example, a commercial AC power source or a private power generation device (not shown). The power supply circuit unit 22 can also receive external power supply voltages such as the above-mentioned commercial AC or a centralized power supply unit provided in a mobile object, and can convert and output the above-mentioned driving power supply voltage. Furthermore, it can be configured so 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 commercial AC or the like and the power reception is interrupted due to a power outage, it can be configured so that the operation of the wireless communication unit 1 can be continued by switching to receiving power from the secondary battery module 21.

Next, FIG. 4 is a block diagram showing an example of the electrical configuration of UE (mobile terminal) 5. UE 5 is configured as a smartphone equipped with a microcomputer 100 as a processing main body. Microcomputer 100 is composed of a CPU 101, RAM 102 which serves as a program execution area, ROM 103, input/output unit 104, and bus 106 which interconnects them. In addition, flash memory 105 is connected to bus 106, in which an OS (not shown) for constructing the operating environment of UE 5, terminal application 105b, etc. are installed.

The input/output unit 104 is also connected to a monitor 109 via a graphic controller 1091. A touch panel 110, which constitutes an input unit, is superimposed on the monitor 109, and various information required for controlling the operation of the UE 5 is input in cooperation with various software operation units (such as buttons and icons) displayed on the monitor 109. The touch panel 110 is connected to the input/output unit 104 via a touch panel controller 1101. A camera 111 for taking still 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 wireless base station unit 4 of the wireless communication unit 1 in FIG. 3 via a terminal wireless bearer 57 via the wireless communication unit 112.

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

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

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

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

Next, Figure 9 shows uplink channel mapping in an LTE system. As with Figure 8, it shows the mapping relationship between the logical channel (Downlink Logical Channel), the transport channel (Downlink Transport Channel), and the physical channel (Downlink Physical Channel). Each will be explained in order below.

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

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

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

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

In the downlink of the LTE system, the UE 5 and the relay wireless communication unit 9 wirelessly connect to the wireless base station unit 4 by using Orthogonal Frequency-Division Multiplexing (OFDM) access (OFDMA). The OFDMA method is characterized as a two-dimensional multiplexing access method that combines frequency division multiplexing and time division multiplexing. Specifically, subcarriers on the orthogonal frequency axis and time axis are divided and allocated to the UE 5, and the orthogonal subcarriers on the frequency axis are divided so that the signal of each subcarrier becomes zero (0 point). By dividing the subcarriers and allocating them on the frequency axis, it is possible to select another subcarrier that is not affected even if a certain subcarrier is affected by fading, so that the user can use a better subcarrier according to the wireless environment, and the wireless quality can be maintained.

In the OFDMA system, resource blocks (hereinafter also referred to as RBs) defined on a virtual plane spanned by a frequency axis and a time axis are adopted as radio resources. As shown in FIG. 10, RBs are defined as blocks obtained by dividing the above plane into a matrix of 180 kHz/0.5 msec, and each block includes 12 adjacent subcarriers spaced 15 kHz apart on the frequency axis and one slot (7 symbols) of a frame on the time axis. Two adjacent RBs (1 msec) on the time axis are assigned to the UE 5 and the relay radio communication unit 9 as a set. On the other hand, in the uplink of the LTE system, resource blocks of a similar concept are used as radio resources, except that SC-FDM (Single Carrier 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 method in which no division into subcarriers occurs.

In a wireless communication method according to the 3GPP specifications, one of the multiple frequency bands defined in the 3GPP is assigned. The assigned frequency band differs depending on the communication method. 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 multiple frequency channels of a predetermined bandwidth, and the EPC function unit 3 selects a predetermined frequency channel to construct the wireless link 55 and terminal wireless bearer 57 in FIG. 2. In other words, the downstream node unit channel, the upstream node unit channel, and the terminal side channel are each set as a frequency channel belonging to one of the multiple bands defined in 3GPP.

In the embodiment of FIG. 11, the EPC function unit 3 fixes the setting frequency channel of the (downstream) radio link 55 to a (downstream) inter-unit channel, which is a specific predetermined frequency channel. In addition, the terminal side channel, which is the setting frequency channel of the terminal radio bearer 57, is set to the same frequency channel as the (downstream) inter-unit channel. In other words, the EPC function unit 3 sets the same frequency channel for the relay radio communication unit 9 of the downstream radio communication unit 1 and the mobile terminal 5 with respect to the radio base station unit 4 directly below.

In addition, in FIG. 11, the cell of wireless communication unit 1(A), the cell of wireless communication unit 1(B), and the cell of wireless communication unit 1(C) overlap each other. In this case, for example, by setting the inter-unit channels of wireless links 55(A) and (B) connecting wireless communication units 1(A) and 1(C) upstream and downstream from wireless communication unit 1(B) to different frequency channels, radio interference between the multiple overlapping cells involved in the construction of wireless links 55(A) and (B) can be effectively prevented.

More specifically, when an (upstream) wireless link is constructed, the EPC function unit 3 of each of the wireless communication units 1(A) to 1(C) sets the downstream node unit inter-channel to a frequency channel different from the upstream node unit inter-channel set for the upstream wireless link, while the terminal channel group is set as a frequency channel group different from both the downstream node unit inter-channel and the upstream node unit inter-channel. For example, when focusing on the wireless communication unit 1(B), the EPC function unit 3 of the wireless communication unit 1(B) sets the upstream node unit inter-channel set for the upstream wireless link 55(B) to, for example, CH2. On the other hand, the EPC function unit 3 of the wireless communication unit 1(A) sets the upstream node unit inter-channel (the downstream node unit inter-channel as seen from the wireless communication unit 1(B)) set for the upstream wireless link 55(A) as seen from the wireless communication unit 1(A) (the downstream wireless link as seen from the wireless communication unit 1(B)) to CH1, which is different from the above CH2. In this case, by setting the downstream node unit channel CH1 and the upstream node unit channel CH2 as different frequency channels within the same band, the hardware of the wireless base station unit 4 and the relay wireless communication unit 9 for establishing a wireless link can be easily configured with single-band specifications.

The terminal side channel is set to the same channel as the downstream node unit channel among the frequency channels belonging to the same band. For example, when only one band is assigned to the entire wireless network system of FIG. 11, the terminal side channel is set to the same channel as the downstream node unit channel among the frequency channels belonging to the same band, thereby enabling the hardware of the wireless base station unit 4 and the relay wireless communication unit 9 to be specified in a single band, including the construction of the terminal wireless bearer, which contributes to simplifying the device configuration. The terminal side channel may be switchably selected from the remaining frequency channels other than those set as the downstream node unit channel and the upstream node unit channel.

In this embodiment, band 28 defined by 3GPP is used as the same band. Band 28 is set in the VHF band (700 MHz band) that became available following the termination of terrestrial analog television broadcasting. Band 28 is a low frequency band, so the communication speed is somewhat slow, and therefore it has not been actively adopted in areas with many terminal subscribers, such as urban areas, and the utilization situation of radio wave resources is not so tight, so smooth connection can be expected. In addition, being a low frequency band, it has excellent radio wave long-distance reach, and it is possible to expand the cell coverage of one wireless communication unit. In addition, it has the characteristic of being easy to connect even underground or in the presence of obstacles, and it can be said that it is suitable for constructing the wireless network system of the present invention, for example, at sea or in a mine.

Next, in the wireless network system of the present invention, a specific method for making the inter-unit channel settings of adjacent wireless links 55(A) and 55(B) different from each other as shown in FIG. 11 can be achieved by, for example, each wireless communication unit 1(A)-1(C) sharing inter-unit channel information by sending and receiving the above-mentioned link notification packet via wireless links 55(A) and 55(B).

In addition, when the upper limit number of wireless communication units participating in the wireless network system is set, for example, in FIG. 11, it is effective to uniformly determine the type of inter-unit channel to be allocated in the form of a channel map according to the combination of node addresses assigned to each wireless communication unit 1 (A) to 1 (C) and incorporate this channel map into the EPC function unit 3 of each wireless communication unit in order to further simplify the processing. Each EPC function unit 3 can set the inter-unit channels of adjacent wireless links to be different by referring to the channel map. In this case, the EPC function unit 1 has a channel map storage unit that stores a channel map indicating the correspondence between the frequency channel group that can be selected as the downstream node unit channel and the node address of the downstream relay wireless communication unit to which it is connected, and when it receives an attach request from the downstream relay wireless communication unit, it acquires the node address of the downstream relay wireless communication unit, identifies the frequency channel corresponding to the acquired node address on the channel map, and operates to set the identified frequency channel as the downstream node unit channel.

Figure 12 shows an example of a channel map 305g. In this channel map 305g, there are four wireless communication units 1 participating in the system construction, each of which is assigned unit identification information MID01 to MID04. Depending on the combination of unit identification information, the channel numbers of the inter-unit channels set between the corresponding wireless communication units are determined so as not to overlap. The unit identification information may be the authentication information IMSI (International Mobile Subscriber Identity) of the wireless communication unit 1, or it may be a node address.

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. 16 and 17. Fig. 16 shows the attach sequence of the relay wireless communication unit 9. 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. At this time, the relay wireless communication unit 9 transmits an IMSI for authentication. In response to this, the MME 2 transmits a bearer setting request to the S-GW 6 in TS2. In TS3, the S-GW 6 executes bearer setting processing for a physical line on the S5 interface with the P-GW 7. Once the bearer is set, the S-GW 6 transmits a bearer setting response to the MME 2 in TS4.

The MME2 searches for the wireless communication channel corresponding to the requesting unit on the channel map 305g (FIG. 12) in TS5. Then, in TS6, it notifies the wireless base station unit 4 of a wireless bearer setting request (attach acceptance) together with the setting channel number. In response to this, the wireless base station unit 4 transmits to the relay wireless communication unit 9 in TS7 a MIB (Master Information Block) including the setting channel number of the wireless bearer (wireless link) to be set.

At TS8, the relay wireless communication unit 9 sets the inter-unit channel to a fixed channel number included in the received MIB and replies with a notification that the setting is complete. In response, at TS9, the wireless base station unit 4 notifies the relay wireless communication unit 9 of a session start request (touch acceptance). At TS10, the relay wireless communication unit 9 sets a wireless link and returns a session start response to the wireless base station unit 4. At TS11, the wireless base station unit 4 notifies the MME 2 of the session start response.

Meanwhile, Figure 17 shows the attach sequence of UE5 (mobile terminal). In TS11', UE5 issues an attach request to MME2 via wireless base station unit (eNodeB) 4. At this time, the IMSI of the wireless communication unit is transmitted to the request source. MME2 receives this and transmits a bearer setting request to S-GW6 in TS12. S-GW6 executes bearer setting processing of a physical line on the S5 interface with P-GW7 in TS13. Once the bearer is set, S-GW6 transmits a bearer setting response to MME2 in TS14.

The MME2 determines the setting channel number that can be used as the terminal radio bearer group according to the process in FIG. 13. Then, in TS16, it notifies the radio base station unit 4 of a radio bearer setting request (attach acceptance) together with the determined setting channel number. In response to this, in TS17, the radio base station unit 4 transmits to the UE5 a MIB (Master Information Block) including the setting channel number of the radio bearer (radio link) to be set.

At TS18, UE5 sets the terminal-side channel to the setting channel number included in the received MIB and replies with a notification that the setting is complete. In response, at TS19, the radio base station unit 4 notifies UE5 of a session start request (attach acceptance). At TS20, UE5 sets a terminal-side radio bearer and returns a session start response to the radio base station unit 4. At TS21, the radio base station unit 4 notifies MME2 of the session start response. As described above, the attach sequence of UE5 and the attach sequence of relay radio communication unit 9 are executed according to basically the same procedure, except for the contents of the frequency channel setting.

In the LTE system, in order to flexibly change the amount of broadcast information such as the above-mentioned setting channel number for each operation and environment, a fixed broadcast information resource using PBCH and a variably usable radio resource using PDSCH are used in combination. The reason why the fixed resource PBCH is used here is because the broadcast information is defined as the information that the UE 5 (relay radio communication unit 9) acquires first, and the UE 5 (relay radio communication unit 9) needs to be able to receive it without receiving a notification from the radio base station unit (eNodeB) 4. The UE 5 first receives the fixed resource PBCH, obtains the minimum information required to receive the PDSCH from the PBCH, and reads the broadcast information sent on the PDSCH based on that information. Since the PDSCH is a variable resource that can be assigned in RB units, the amount of broadcast information transmitted on the PDSCH is variable. This realizes the change of the amount of resources used for broadcast information, and makes it possible to assign radio resources according to the amount of broadcast information that differs depending on the network operation and environment.

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

Figure 18 shows the flow of IP packet transmission processing between UE5 (UE(I) and UE(II)) connected to the same wireless communication unit 1. U1 and U2 are the attach sequences already explained in Figure 15, and a terminal wireless bearer is constructed. At U3, an IP packet is sent from UE(I) to the wireless base station unit 4 as an uplink packet. The wireless base station unit 4 transfers this to the EPC function unit 3. The EPC function unit 3 checks whether the IP address of any UE connected to its own node unit 1(A) matches the destination address recorded in the header of the received IP packet. In the case of Figure 18, the IP address of UE(II) corresponds to this, and at D1, the IP packet is transferred back to the subordinate wireless base station unit 4 as a downlink packet. The wireless base station unit 4 receives this and transfers it to UE(II), completing the process.

Figure 19 shows the flow of IP packet transmission processing between UE5(A) connected to wireless communication unit 1(A) and UE5(B) connected to adjacent wireless communication unit 1(A) in Figure 11. The processing from U1 to U3 is the same as that in Figure 18. At U3, the EPC function unit 3 of wireless communication unit 1(A) refers to the routing management table 305f in Figure 13, and confirms that the destination address of the received IP packet does not match the IP address of any UE connected to its own node unit 1(A), and confirms whether the destination address is on the upstream route or the downstream route. For example, if the destination address is on the upstream route side, the IP packet is transferred to the wireless communication unit 1(B) on the upstream side at U4 via the wireless link 55(A). The wireless communication unit 1(B) receives this IP packet, and similarly confirms whether the IP address of any UE connected to its own node unit 1(B) matches the destination address recorded in the header of the received IP packet. If there is a match, the IP packet is forwarded as a downstream packet at D2 to the subordinate wireless base station unit 4. The wireless base station unit 4 receives it and forwards it to UE5 (B), completing the process.

For example, if the UE that sends the IP packet is connected to the middle one of a group of cascaded wireless communication units, and the destination UE is a UE connected to a wireless communication unit downstream of the wireless communication unit, the EPC function unit 3 at U3 above will refer to the routing management table 305f and confirm that the destination address of the received IP packet matches the IP address of the UE on the downstream route. The IP packet is transferred as a downlink packet to the wireless base station unit 4, and is further transferred to the wireless communication unit to which the destination UE is connected using the downstream associated wireless bearer.

Figure 20 shows the flow of IP packet transmission processing between UE5(A) connected to wireless communication unit 1(A) and UE5(C) connected to wireless communication unit 1(C), which is two units ahead, in Figure 11. The processing from U1 to U4 is the same as in Figure 19. At U4, the EPC function unit 3 of wireless communication unit 1(B) refers to the routing management table 305f, and if it is confirmed that the destination address recorded in the header of the received IP packet exists, for example, on the upstream route side, it transfers the IP packet to the wireless communication unit 1(C) on the upstream side at U5 via the wireless link 55(B). The wireless communication unit 1(C) receives this IP packet and confirms that the IP address of UE5(C) connected to its own node unit matches the IP address of the destination. Then, at D3, it transfers the IP packet as a downstream packet to the subordinate wireless base station unit 4. The wireless base station unit 4 receives it and transfers it to UE5(C), completing the processing.

Figure 21 shows the processing when an IP packet from UE 5 (A) connected to wireless communication unit 1 (A) has a destination address outside the wireless network system. The processing from U1 to U5 is the same as in Figure 20. At U5, the EPC function unit 3 of wireless communication unit 1 (C) refers to the routing management table 305f and confirms that the destination address recorded in the header of the received IP packet exists on the upstream route, and at U6, forwards the IP packet to router 8.

The communication firmware 305a having the above-mentioned configuration functions as a program for implementing the following functional units related to creating and updating the routing management table 305f (see FIG. 11).
Routing management information reception control command unit: Instructs the linkage notification information transmission/reception control unit to receive, as linkage notification information, from an upstream node unit or downstream node unit, routing management information including the node address of a mobile terminal (UE) 5 connected to the wireless base station unit of a wireless communication unit connected upstream or downstream from the own node unit as the other node unit.
Routing management information integration processing unit: Integrates routing management information including the node address of the mobile terminal 5 connected to the wireless base station unit 4 of the own node unit with routing management information of other node units received from an upstream node unit or downstream node unit.
Routing management information storage control unit: stores the integrated routing management information in a routing management information storage unit (corresponding to the storage area of the routing management table 305f of the flash memory 305 in FIG. 3).
Routing management information transmission control command unit: commands the association notification information transmission/reception control unit to transmit the integrated routing management information as association notification information to a downstream node unit or an upstream node unit.
User data forwarding control unit: By referring to the routing management information stored in the routing management information storage unit, the unit identifies the node address of the mobile terminal 5 to which the user data is to be forwarded, and controls the forwarding of the user data on the user plane side of the communication protocol stack.

With the above configuration, the process of sending and receiving association notification packets on the wireless association protocol layer WLP can smoothly and easily execute the process of sharing routing management information between multiple wireless communication units 1 that are connected in association. An example of a specific process flow will be described below with reference to Figures 14A and 14B. Here, we take as an example a case where wireless communication units 1(A) to 1(C) are in the connection state shown in Figure 11.

The update process of the routing management table 305f is performed back and forth between the wireless communication unit 1 (A) located at the downstream end of the wireless network system and the wireless communication unit 1 (C) located at the upstream end by a bucket brigade-like method using a link notification packet. That is, the wireless communication unit 1 (A) at the downstream end, which is the processing start point, issues a link notification packet that notifies the node address of the UE5 (and application server 8') connected to its own node unit as an update trigger packet and transmits it to the upstream node unit. The upstream node unit that receives this updates the contents of the downstream route side of the routing management table 305f by referring to the contents of the link notification packet, and transmits the updated contents of the downstream route side to the next upstream node unit by a link notification packet (FIG. 14A). Then, when this transmission flow reaches the wireless communication unit 1 (C) at the upstream end, the wireless communication unit 1 (C) at the upstream end updates the contents of the downstream route side of the routing management table 305f, and issues a link notification packet that notifies the node address of the UE5 (and application server 8') connected to its own node unit and transmits it to the downstream node unit. The downstream node unit that receives this updates the contents of the upstream route side of the routing management table 305f by referring to the contents of the association notification packet, and transmits the updated contents of the upstream route side to the next downstream node unit by the association notification packet (FIG. 14B). Then, when this transmission flow returns to the wireless communication unit 1(A) at the downstream end, the wireless communication unit 1(A) updates the contents of the upstream route side of the routing management table 305f, and the series of processes is completed. This sequence is repeated by the wireless communication unit 1(A) at the downstream end periodically (for example, at a predetermined time interval) issuing the above update trigger packet, and the routing management table 305f can be kept up to date.

The following is a more detailed explanation. First, the EPC function unit 3 of the wireless communication unit 1 (A) at the downstream end issues an association notification packet in which the node address (192.168.1.0/24) of the UE 5 connected to its own node unit and the node address (172.16.1.0/24) of the application server 8' are incorporated in the payload. Then, the association notification packet is transmitted to the relay wireless communication unit (BTC) 9 via the upstream wireless link 55 (A) (U101). The wireless communication unit 1 (B) receives this at the wireless base station unit 4, and updates the contents of the downstream route side of the routing management table 305f with the above-mentioned node address written in the association notification packet (U102).

At this time, in this embodiment, it can be obviously identified from any of the following logics that the source of the association notification packet is a downstream node unit as viewed from the wireless communication unit 1(B).
(1) The association notification packet is received by the wireless base station unit 4.
(2) The source address written in the association notification packet indicates the node address of the downstream node unit. The source of the association notification packet is the EPC function unit 3, and it is possible to know whether the source address is that of the downstream node unit or the downstream node unit by referring to the topology management table 305tt.

Then, the EPC function unit 3 of the wireless communication unit 1 (B) integrates the node address (192.168.1.0/24) of the UE 5 connected to its own node unit and the node address (172.16.2.0/24) of the application server 8' received from the wireless communication unit 1 (A) with the node address (192.168.2.0/24) of the UE 5 connected to its own node unit and the node address (172.16.2.0/24) of the application server 8', and issues an association notification packet with these incorporated in the payload. Then, it causes the relay wireless communication unit (BTC) 9 to transmit the association notification packet via the upstream wireless link 55 (B) (U103).

The EPC function unit 3 of the wireless communication unit 1(C) at the upstream end receives the above-mentioned cooperation notification packet at the wireless base station unit 4, and updates the contents of the downstream route side of the routing management table 305f with the above-mentioned node address written in the packet (U104). On the other hand, since no upstream node unit is connected to the wireless communication unit 1(C), the contents of the upstream route side of the routing management table 305f are blank (see bottom of Figure 13). With the sequence up to this point, the update of the contents of the downstream route side of the routing management table 305f of each wireless communication unit 1(A) to 1(C) is completed.

Next, in FIG. 14B, the wireless communication unit 1 (C) at the upstream end issues an association notification packet in which the node address (192.168.3.0/24) of the UE 5 connected to its own node unit and the node address (172.16.3.0/24) of the application server 8' are incorporated in the payload. Then, the wireless base station unit 4 transmits the association notification packet via the downstream wireless link 55 (B) (U105). The wireless communication unit 1 (B) receives this at the relay wireless communication unit 9, and updates the contents of the upstream route side of the routing management table 305f with the above-mentioned node address written in the association notification packet (U106). At this point, the contents of the routing management table 305f of the wireless communication unit 1 (B) are as shown in the center of FIG. 13.

At this time, in this embodiment, it can be obviously identified from any of the following logics that the source of the association notification packet is the upstream node unit as viewed from the wireless communication unit 1(B).
(3) The association notification packet is received by the relay wireless communication unit 9.
(4) The source address written in the association notification packet indicates the node address of the upstream node unit in the topology management table 305tt.

Then, the EPC function unit 3 of the wireless communication unit 1 (B) integrates the node address (192.168.3.0/24) of the UE 5 connected to its own node unit and the node address (172.16.2.0/24) of the application server 8' received from the wireless communication unit 1 (C) with the node address (192.168.2.0/24) of the UE 5 and the node address (172.16.2.0/24) of the application server 8', and issues an association notification packet with these incorporated in the payload. Then, it causes the wireless base station unit 4 to transmit the association notification packet via the downstream wireless link 55 (A) (U107).

The EPC function unit 3 of the wireless communication unit 1(A) at the downstream end receives the above-mentioned cooperation notification packet at the relay wireless communication unit 9, and updates the contents of the upstream route side of the routing management table 305f with the above-mentioned node address written in the packet (U104). On the other hand, since no downstream node unit is connected to the wireless communication unit 1(A), the contents of the downstream route side of the routing management table 305f are blank (see the top of Figure 13). With the above sequence, the content update process of the routing management table 305f of each wireless communication unit 1(A) to 1(C) is completed.

If the connection state of UE5 of each wireless communication unit 1(A) to 1(C) changes, it will be reflected in the routing management table 305f at the time of the next update process. At this time, the contents of the routing management table 305f are replaced with new contents by erasing the old contents (i.e., updated).

It is also possible to obtain the node address of the UE5 (and application server 8') currently connected to the node unit individually by using the association notification packet issued by each wireless communication unit 1 (A) to 1 (C) and update the routing management table 305f. In this case, the topology management table 305tt distinguishes between the upstream and downstream senders of the association notification packet, and the upstream route side and downstream route side of the routing management table 305f are updated each time an association notification packet is received. Here, if a disconnected UE5 occurs, a separate procedure is required to erase the node address of the UE5 from the routing management table 305f. Specifically, it is necessary to either notify the node address of the disconnected UE5 by using an association notification packet, or to manage the node address of the connected UE5 (and application server 8') in association with the node address of the wireless communication unit on the routing management table 305f. However, if the above-mentioned method is used in which the node addresses of UE5 (and application server 8') connected to each node unit are integrated in the intermediate wireless communication unit 1 (B) and notified by a link notification packet, it is possible to significantly simplify the process by simply erasing the existing contents of the routing management table 305f.

Next, the communication firmware 305a also functions as a program for realizing the following functional units related to creating and updating the topology management table 305tt (see FIG. 11).
- Wireless connection topology information reception control command unit: Instructs the linkage notification information transmission/reception control unit to receive, as linkage notification information, wireless connection topology information that identifies each wireless communication unit included in the wireless communication unit group 1 (A) to 1 (C) connected upstream or downstream of the own node unit, together with the connection order, from the upstream node unit or downstream node unit.
Wireless connection topology information update processing unit: updates the contents of the wireless connection topology information received from an upstream node unit or a downstream node unit by incorporating the local node unit into the wireless communication unit group specified by the wireless connection topology information.
Wireless connection topology information storage control unit: stores the updated wireless connection topology information in a wireless connection topology information storage unit (corresponding to the storage area of the topology management table 305tt of the flash memory 305 in FIG. 3).
Wireless connection topology information transmission command unit: issues a command to the association notification information transmission/reception control unit to transmit the updated wireless connection topology information to the downstream node unit or the upstream node unit.
In this case, the user data transfer control unit controls the transfer of user data based on the wireless connection topology information stored in the wireless connection topology information storage unit.

With the above configuration, the sharing process of topology management information between multiple wireless communication units 1 connected in cooperation can be smoothly and easily executed by the transmission and reception process of cooperation notification packets on the wireless cooperation protocol layer WLP. Hereinafter, an example of the specific process flow will be described with reference to FIG. 15. Here again, the case where the wireless communication units 1 (A) to 1 (C) are in the connection state of FIG. 11 will be taken as an example. The basic process flow is performed back and forth between the wireless communication unit 1 (A) located at the downstream end of the wireless network system and the wireless communication unit 1 (C) located at the upstream end by a bucket brigade-like method similar to the update process of the routing management table 305f. That is, the wireless communication unit 1 (A) at the downstream end, which is the processing start point, issues a cooperation notification packet incorporating the node address [A] of its own node unit and the node address [B] of the upstream node unit as wireless connection topology information ([A] → [B]) reflecting, for example, the arrangement order (connection order) from the downstream side to the upstream side, as an update trigger packet and transmits it to the upstream node unit (U201).

The wireless communication unit 1 (B), which is the upstream node unit, updates the contents of the topology management table 305tt with the wireless connection topology information ([A] → [B]) of the received association notification packet (U202). Next, the upstream node unit 1 (B) updates the received wireless connection topology information ([A] → [B]) by adding the node address ([C]) of the next upstream node unit to the upstream side, and transmits the updated wireless connection topology information ([A] → [B] → "C") to the wireless communication unit 1 (C), which is the upstream node unit, using an association notification packet (U203).

When the flow of transmission of the association notification packet reaches the wireless communication unit 1 (C) at the upstream end, the wireless communication unit 1 (C) at the upstream end updates the contents of the topology management table 305tt with the received wireless connection topology information (U204), and the local node unit recognizes this as the latest wireless connection topology information ([A] → [B] → "C"), which it transmits to the downstream node unit, wireless communication unit 1 (B), by association notification packet (U205). The downstream node unit, wireless communication unit 1 (B), which receives this, updates the topology management table 305tt with the contents of the wireless connection topology information in the received association notification packet. The wireless communication unit 1 (A) at the downstream end updates the contents of the topology management table 305tt with the received wireless connection topology information, completing the series of processes. This sequence is repeated by the wireless communication unit 1 (A) at the downstream end periodically (for example, at a predetermined time interval) issuing the update trigger packet described above, and the topology management table 305tt can be kept up to date.

The communication firmware 305a also functions as a program for realizing the following functional sections related to determining and controlling whether or not to accept an attachment when an attachment request is received from a new wireless communication unit (candidate unit) further downstream when the own node unit is the downstream end node unit.
- Provisional wireless link construction control unit: Prior to actually establishing a downstream wireless link with a candidate unit, which is a wireless communication unit that is a candidate for a downstream node unit, a provisional wireless link is constructed with the candidate unit by receiving an attach request from the candidate unit.
- Judgment reference information reception control command unit: Instructs the association notification information transmission/reception control unit to receive judgment reference information, which is used to judge whether to allow the final construction of a downstream wireless link to a candidate unit, as association notification information from the candidate unit via a temporary wireless link.
Downstream radio link final establishment permission determination unit: determines whether or not to permit the final establishment of a downstream radio link for a candidate unit based on the received determination reference information.
Downstream wireless link construction control unit: If the result of the determination as to whether or not to permit this construction is positive, the provisional wireless link is transitioned to a formal construction state as a downstream wireless link, whereas if the result of the determination as to whether or not to permit this construction is negative, a detach sequence is executed to cancel the construction state of the provisional wireless link.

According to the above configuration, by first establishing a provisional wireless link with a candidate unit with which a wireless link has not been established, it is possible to accurately and easily obtain the determination reference information from the candidate unit in the form of an association notification packet, and by referring to this, it is possible to smoothly and accurately determine whether or not an association connection with the candidate unit is possible (determination of whether or not to permit the actual establishment of a downstream wireless link). Furthermore, if the determination result is positive, it is possible to smoothly transition to the actual establishment state of the downstream wireless link by taking over the provisional wireless link, whereas if the determination result is negative, a detach sequence is executed to cancel the establishment state of the provisional wireless link, thereby effectively preventing an association connection with an inappropriate candidate unit.

The determination reference information can include wireless connection topology information that identifies, for a wireless communication unit group including a candidate unit connected downstream or upstream of the own node unit, each wireless communication unit included in the wireless communication unit group together with the connection order. In this case, the downstream wireless link final construction permission determination unit can be configured to determine that the final construction of a downstream wireless link to a candidate unit is not permitted when the connection form of the wireless communication unit group indicated by the wireless connection topology information corresponds to a predetermined prohibited connection form. By referring to the wireless connection topology information, it is possible to effectively prevent a cooperative connection with a candidate unit that attempts to connect to the downstream end node unit through an inappropriate topology.

In this case, the prohibited connection form can be defined as a connection form in which the candidate unit is a wireless communication unit that is the same as one of the other node units connected upstream of the own node unit. If such a candidate unit's cooperative connection is not prohibited, the connection topology of the wireless communication unit via the wireless link will be endless (i.e., form a loop) between at least some of the wireless communication unit groups. For the wireless communication unit belonging to the endless section, it becomes difficult to distinguish between the wireless communication unit group on the upstream route side and the wireless communication unit group on the downstream route side as seen from the own node unit, which causes a problem of complicating the routing management algorithm. In addition, all of the wireless base station units 4 of the wireless communication units belonging to the endless section are always in a state where part of the transmission and reception bandwidth is occupied by the construction of wireless links with other node units, so when the number of connected UEs 5 increases, communication traffic may be strained. Therefore, the above problem can be solved by prohibiting the connection form.

In addition, the attach request from an unqualified candidate unit may be repeatedly executed while the candidate unit is close to the downstream node unit, which may hinder smooth communication processing of the downstream node unit. From the viewpoint of preventing such problems, it is effective to configure the communication control unit to include the following requirements.
Unit identification information acquisition unit: upon receiving an attach request from a candidate unit, acquires from the candidate unit unit-specific unit identification information that is unique to the candidate unit.
Connection-denied unit registration control unit: if the decision as to whether to permit the establishment of a downstream wireless link for a candidate unit is negative, the unit identification information of the candidate unit is registered in the connection-denied unit registration unit (FIG. 3: rejection list 305rr).
Unit identification information matching section: When an attach request is received again from a candidate unit after the execution of a detach sequence, the unit identification information acquired from the candidate unit is matched with the unit identification information registered in the connection unauthorized unit registration section.
In this case, the provisional wireless link construction control unit is configured to accept an attach request from the candidate unit and construct a provisional wireless link if the unit identification information that matches the unit identification information acquired from the candidate unit is not registered in the connection non-permitted unit registration unit, and to reject an attach request from the candidate unit if the unit identification information is registered in the connection non-permitted unit registration unit.

According to the above configuration, when an unqualified candidate unit makes a first attachment request, the unit identification information is obtained from the candidate unit and registered as a connection-unauthorized unit. In the case of a second or subsequent attachment request, the unit identification information is collated to reject the attachment, thereby avoiding a linkage connection with the candidate unit. This prevents the attachment sequence for establishing a tentative wireless link from being executed in the case of a second or subsequent attachment request from an unqualified candidate unit, thereby preventing the communication process of the downstream node unit from being hindered. Note that even if a candidate unit is determined to be "unqualified" at a certain point in time, the cause of the unqualification may be eliminated over time. In this case, the connection-unauthorized unit registration control unit is configured to register the unit identification information in the connection-unauthorized unit registration unit for a predetermined registration validity period, and to invalidate the registration state of the unit identification information when the registration validity period expires, so that a linkage connection via a wireless link from a candidate unit whose cause of unqualification has been eliminated can be accepted without any problems.

The unit identification information acquisition unit can be configured to acquire IMSI information for connection authentication of the candidate unit as unit identification information in the attach sequence for the candidate unit. The IMSI is subscriber identification information written in a SIM (Subscriber Identity Module) card of the candidate unit, for example, which is attached to and detached from the relay wireless communication unit 9. In the LTE attach sequence, in order to authenticate the subscriber of a terminal device such as the UE 5 or the relay wireless communication unit 9, the IMSI is transmitted from the terminal device to the downstream node unit via the PUSCH as a procedure, and by utilizing this, there is an advantage that unit identification information can be easily acquired from the candidate unit.

The virtual wireless link construction control unit can be configured to transmit notification information to the candidate unit, which, when rejecting an attach request from the candidate unit, prompts the candidate unit to extend the period until the next attach request made to the candidate unit. This can prevent a candidate unit that has once rejected an attach request from frequently receiving reattach requests at short intervals (such an operation can also hinder the registration operation of the unit specific information in the rejection list 305rr (FIG. 3)). As the notification information, a cause code for the attachment rejection (Cause Code: transmitted using PDSCH) returned from the downstream node unit to the relay wireless communication unit 9, which is a terminal device on the candidate unit side, can be adopted. For example, in the LTE specification, a candidate unit that has received cause code 22 (Congestion) is permitted to reattach to the wireless base station unit 4 only after a certain period of time has elapsed in anticipation of the resolution of the congestion state, thereby realizing processing that meets the above purpose. It is also effective to use cause code 15 (move to another tracking area candidate). In the LTE specification, a candidate unit that receives a reason code attempts to attach to a wireless base station unit 4 that belongs to another tracking area, so it is possible to extend the time until it again requests attachment from the downstream node unit that was rejected for attachment.

An example of a specific processing flow will be described below with reference to Figs. 22 to 24. Here, an example is taken of a case where a wireless communication unit 1 (A) is a candidate unit and connects to the wireless base station unit 4 of a wireless communication unit 1 (B) which is a downstream node unit. First, as shown in Fig. 22, the wireless communication unit 1 (A) which is a candidate unit has the aforementioned isolated mode state established in the wireless cooperation protocol layer module 305p (wireless link management module 305pj) of the EPC function unit 3 before attachment (M101). Meanwhile, the relay wireless communication unit 9 of the wireless communication unit 1 (A) performs a cell search by transmitting a search radio wave at T101.

The wireless base station unit 4 of the wireless communication unit 1 (B) returns notification information indicating that the search radio wave has been received to the relay wireless communication unit 9 of the wireless communication unit 1 (A) using an MIB or SIB (T102). In response to this, the relay wireless communication unit 9 makes an attach request to the wireless base station unit 4 in T103. In T104, the attach sequence detailed in FIG. 16 is executed, and a tentative wireless link is established.

The relay wireless communication unit 9 of the wireless communication unit 1 (A) notifies the wireless cooperation protocol layer module 305p of wireless link update information indicating the establishment of a tentative wireless link. As a result, the operation mode of the wireless communication unit 1 (A) transitions to the cooperation mode (M102). In response to this, the wireless cooperation protocol layer module 305p starts the routing management module 305pr and the topology management module 305pt, and transmits the routing management information (see U101) described in FIG. 14A and the topology management information (U201) described in FIG. 15 to the wireless cooperation protocol layer module 305p of the EPC function unit 3 of the wireless communication unit 1 (B) by means of an cooperation notification packet. In the figure, the thick dashed lines indicate the flow of information via the cooperation notification packet.

In the wireless cooperation protocol layer module 305p, the topology management module 305pt analyzes the connection topology between the wireless communication unit 1(A) and the wireless communication unit 1(B) indicated in the received topology management information, and determines whether it corresponds to a prohibited connection topology (T107: Topology update inquiry). FIG. 22 shows a case where it corresponds to a prohibited connection topology, such as the formation of the aforementioned endless part (loop), and the topology management module 305pt rejects the topology update (T108). In addition, the IMSI obtained for authentication from the relay wireless communication unit 9 of the wireless communication unit 1(A) is registered in the rejection list 305rr for a certain period of time (T109).

The wireless cooperation protocol layer module 305p receives this flow and requests the EPC function unit 3 to disconnect (detach) the virtual wireless link (T110). The control information related to T107 to T110 is exchanged by the wireless communication unit 1 (B) through the transmission and reception of cooperation notification packets within the EPC function unit 3 on the wireless cooperation protocol layer.

Then, in T111, the EPC function unit 3 of the wireless communication unit 1 (B) executes a detach sequence with the relay wireless communication unit 9 of the wireless communication unit 1 (A), and the virtual wireless link is disconnected. The relay wireless communication unit 9 of the wireless communication unit 1 (A) notifies the wireless cooperation protocol layer module 305p of wireless link update information indicating disconnection of the virtual wireless link. As a result, the wireless link is updated to a disconnected state (T112), and the operation mode transitions to the isolated mode (M103). Note that the IMSI registered in the rejection list 305rr is erased or invalidated after the above-mentioned certain period has elapsed.

Next, FIG. 23 shows an example of processing when the connection topology between wireless communication unit 1(A) and wireless communication unit 1(B) does not correspond to the prohibited connection topology. The processing from T101 to T103 in FIG. 22 is also performed in this case, but is omitted from FIG. 23. Also, the processing from T304 to T306 in FIG. 23 is the same as the processing from T104 to T106 in FIG. 22.

In FIG. 23, after a provisional wireless link is established (T304) and the wireless link is updated (T305), the EPC function unit 3 of the wireless communication unit 1 (B) that has received the routing management information and topology management information (T306) executes a wireless link update indicating the establishment of a provisional wireless link in T307 by the wireless cooperation protocol layer module 305p. In addition, in T308, the connection topology form indicated by the received topology management information is analyzed by the topology management module 305pt (T308: topology update inquiry). In T309, the topology management module 305pt accepts the connection topology form and updates the topology management table 305tt (topology update acceptance). Meanwhile, in T310, the wireless cooperation protocol layer module 305p inquires of the routing management module 305pr whether the contents of the received routing management information are acceptable (routing update inquiry). The routing management module 305pr accepts the contents of the routing management information at T311 and updates the routing management table 305f (routing update acceptance). The EPC function unit 3 (wireless cooperation protocol layer module 305p) of the wireless communication unit 1 (B) transmits the updated topology management information and routing information to the EPC function unit 3 (wireless cooperation protocol layer module 305p) of the wireless communication unit 1 (A) via an cooperation notification packet. The temporary wireless link is taken over as a wireless link (cooperating wireless bearer) in the actual construction state, and transmission of user data via the wireless link is started (M303).

Finally, FIG. 24 shows the flow of processing when a candidate unit (wireless communication unit 1(A)) whose attachment has been rejected according to the flow of FIG. 22 again requests attachment to wireless communication unit 1(B). The wireless communication unit 1(A) is in isolated mode (M201), and its relay wireless communication unit 9 issues an attachment request to the EPC function unit 3 of the wireless communication unit 1(B) at T201. The EPC function unit 3 of the wireless communication unit 1(B) queries the wireless cooperation protocol layer module 305p about the IMSI transmitted at this time. The topology management module 305pt of the wireless cooperation protocol layer module 305p searches the acquired IMSI on the rejection list 305rr. If the received IMSI matches any of the IMSIs registered in the rejection list 305rr, rejection of the attach request is instructed at T204. As a result, a tentative wireless link is not established.

The EPC function unit 3 of the wireless communication unit 1 (B) notifies the relay wireless communication unit 9 of the wireless communication unit 1 (A) of the attachment rejection by adding a reason code at T201. The reason code number at this time is 22 (congestion), but as described above, it may be 15 (move to another tracking area), etc.

The above describes an embodiment of the present invention, but it is merely an example and the present invention is not limited to this.

1(A), 1(B) Wireless communication units WS(A), WS(B) Large ship 2 MME
3 EPC function unit 300 User data packet 350 Linkage notification packet 301 CPU
302 RAM
303 Mask ROM
304A Upstream communication interface 304B Downstream communication interface 305 Flash memory 305a Communication firmware 305p Wireless cooperation protocol layer module 305pr Routing management module 305f Routing management table 305pt Topology management module 305tt Topology management table 305rr Rejection list 305pj Wireless link management module 305b MME entity 305c S-GW entity 305d P-GW entity 305g Channel map 306 Bus 21 Secondary battery module 22 Power supply circuit unit 23 Portable housing 30, 31 Communication bus 4 Wireless base station unit 401 CPU
402 RAM
403 Mask ROM
404 Communication interface 405 Flash memory 405a Communication firmware 406 Bus 412 Wireless communication unit 5 UE (mobile terminal)
6 S-GW
7 P-GW
8 Router 9 Relay wireless communication unit 901 CPU
902 RAM
903 Mask ROM
905 Flash memory 905a Communication firmware 906 Bus 912 Wireless communication unit 50(A), 50(B) Cell 55 Wireless link (associated wireless bearer)
57 Terminal Radio Bearer

Claims (12)

A wireless communication unit for performing wireless network communication with a mobile terminal according to a communication protocol stack defined by 3GPP (Third Generation Partnership Project),
a radio base station unit to which the mobile terminal can be connected via a terminal radio bearer;
an EPC (Evolved Packet Core) function unit that is connected to the wireless base station unit by wire and functions as a higher-level network control unit for the wireless base station unit;
a relay wireless communication unit that is wiredly connected to the EPC function unit and is attached to a wireless base station unit (hereinafter referred to as an upstream wireless base station unit) of an upstream node unit, which is another wireless communication unit on the upstream side, to enable an association connection with the upstream node unit via an upstream association wireless bearer (hereinafter referred to as an upstream wireless link);
the wireless base station unit is attached from a relay wireless communication unit (hereinafter referred to as a downstream relay wireless communication unit) of a downstream node unit, which is another wireless communication unit on the downstream side, and thereby becomes capable of an association connection with the downstream node unit via a downstream association wireless bearer (hereinafter referred to as a downstream wireless link);
The EPC function unit includes a communication firmware storage unit that stores communication firmware in which the communication protocol stack is embedded, and a communication control unit that performs wireless network communication control by executing the communication firmware,
A wireless cooperation protocol layer is added as a new protocol layer on a layer above a transport layer on a control plane side of the communication protocol stack, the wireless cooperation protocol layer handling transmission and reception of cooperation broadcast information, which is broadcast information used for controlling establishment and management of the cooperation radio bearer between an EPC control unit of the upstream node unit or an EPC control unit of the downstream node unit,
the communication control unit includes a cooperation notification information transmission/reception control unit that incorporates the cooperation notification information into a cooperation notification packet defined on a wireless cooperation protocol layer, and executes transmission/reception control of the cooperation notification information between the upstream node unit or the downstream node unit as transmission/reception control of the cooperation notification packet based on a packet transmission/reception protocol defined on the transport layer ;
The association notification packet is issued as an IP packet having a fixed destination address that also serves as identification information indicating that the association notification packet is the association notification packet.
16. A wireless communication unit comprising: The wireless communication unit according to claim 1 , wherein the transport layer in the communication protocol stack on which the wireless cooperation protocol layer is constructed is a User Datagram Protocol (UDP) layer. The communication control unit
a routing management information reception control command unit which commands the association notification information transmission/reception control unit to receive, as the association notification information, from a wireless communication unit connected upstream or downstream of the own node unit as an other node unit, routing management information including a node address of a mobile terminal connected to the wireless base station unit of the other node unit, from the upstream node unit or the downstream node unit;
a routing management information integration processing unit that integrates routing management information including a node address of a mobile terminal currently connected to the wireless base station unit of the node unit itself with routing management information of the other node unit received from the upstream node unit or the downstream node unit;
a routing management information storage control unit that stores the integrated routing management information in a routing management information storage unit;
a routing management information transmission control command unit that instructs the association notification information transmission/reception control unit to transmit the integrated routing management information as the association notification information to the downstream node unit or the upstream node unit;
a user data transfer control unit that identifies a node address of a mobile terminal to which user data is to be transferred by referring to the routing management information stored in the routing management information storage unit, and controls transfer of the user data on a user plane side of the communication protocol stack;
3. A wireless communication unit according to claim 1 or 2 , comprising: The communication control unit
a wireless connection topology information reception control command unit that instructs the association notification information transmission/reception control unit to receive, as the association notification information, wireless connection topology information that identifies each wireless communication unit included in a wireless communication unit group connected upstream or downstream of the own node unit, together with a connection order, from the upstream node unit or the downstream node unit;
a wireless connection topology information update processing unit that updates the content of the wireless connection topology information received from the upstream node unit or the downstream node unit by incorporating the node unit itself into the wireless communication unit group specified by the wireless connection topology information;
a wireless connection topology information storage control unit that stores the updated wireless connection topology information in a wireless connection topology information storage unit;
a wireless connection topology information transmission command unit that instructs the association notification information transmission/reception control unit to transmit the updated wireless connection topology information to the downstream node unit or the upstream node unit;
4. The wireless communication unit according to claim 3 , wherein the user data transfer control section controls transfer of the user data based on the wireless connection topology information stored in the wireless connection topology information storage section. The communication control unit
a provisional wireless link establishment control unit that establishes a provisional wireless link with a candidate unit, which is a wireless communication unit that is a candidate for the downstream node unit, upon receiving an attach request from the candidate unit, prior to establishing the downstream wireless link with the candidate unit;
a determination reference information reception control command unit that instructs the association notification information transmission/reception control unit to receive, as the association notification information, determination reference information to be referred to in determining whether to allow the establishment of the downstream wireless link for the candidate unit from the candidate unit via the provisional wireless link;
a downstream wireless link final establishment permission determination unit that performs a final establishment permission determination for the downstream wireless link for the candidate unit based on the received determination reference information;
A wireless communication unit as described in any one of claims 1 to 4, further comprising a downstream wireless link construction control unit that transitions the provisional wireless link to a formal construction state as the downstream wireless link if the result of the determination as to whether or not the formal construction is permitted is positive, while executing a detach sequence to cancel the construction state of the provisional wireless link if the result of the determination as to whether or not the formal construction is permitted is negative. the determination reference information includes wireless connection topology information for identifying, with respect to a wireless communication unit group including the candidate unit connected downstream or upstream of the own node unit, each wireless communication unit included in the wireless communication unit group together with a connection order;
The wireless communication unit described in claim 5, wherein the downstream wireless link final construction permission determination unit determines that the final construction of the downstream wireless link to the candidate unit is not permitted when the connection form of the group of wireless communication units indicated by the wireless connection topology information corresponds to a predetermined prohibited connection form. 7. The wireless communication unit according to claim 6, wherein the prohibited connection configuration is a configuration in which the candidate unit is the same wireless communication unit as any one of the other node units connected upstream of the own node unit. The communication control unit
a unit identification information acquisition unit that acquires unit identification information inherent to the candidate unit from the candidate unit upon receiving the attach request from the candidate unit;
a connection-disallowed unit registration control unit that registers the unit identification information of the candidate unit in a connection-disallowed unit registration unit when the determination of whether or not the downstream wireless link is allowed to be established for the candidate unit is negative;
a unit identification information matching unit that, when receiving an attach request from the candidate unit again after the execution of the detach sequence, matches the unit identification information acquired from the candidate unit with unit identification information registered in the connection unauthorized unit registration unit;
The wireless communication unit described in claim 6 or claim 7, wherein the virtual wireless link construction control unit accepts an attach request from the candidate unit and constructs the virtual wireless link if the unit identification information that matches the unit identification information acquired from the candidate unit is not registered in the connection non-permitted unit registration unit , and rejects the attach request from the candidate unit if the unit identification information is registered in the connection non - permitted unit registration unit. The wireless communication unit described in claim 8, wherein the non-connection-permitted unit registration control unit registers the unit identification information in the non-connection-permitted unit registration unit for a predetermined registration validity period, and invalidates the registration status of the unit identification information when the registration validity period expires. 10. The wireless communication unit according to claim 8 , wherein the unit identification information acquisition unit acquires, as the unit identification information, IMSI (International Mobile Subscriber Identity) information for connection authentication of the candidate unit in an attach sequence for the candidate unit. The wireless communication unit according to any one of claims 8 to 10, wherein the virtual wireless link construction control unit, upon rejecting an attach request from the candidate unit, transmits notification information to the candidate unit prompting the candidate unit to extend the period until the next attach request made to the candidate unit. A wireless communication unit for performing wireless network communication with a mobile terminal in accordance with a communication protocol stack defined by 3GPP (Third Generation Partnership Project), comprising: a wireless base station unit to which the mobile terminal can be connected via a terminal wireless bearer; and an Evolved Packet Control (EPC) unit that is wired connected to the wireless base station unit and functions as a higher-level network controller for the wireless base station unit. and a relay wireless communication unit that is wired-connected to the EPC functional unit and that is capable of an association connection with the upstream node unit via an upstream association wireless bearer (hereinafter referred to as an upstream wireless link) by receiving an attachment from a wireless base station unit of an upstream node unit, which is another wireless communication unit on the upstream side, and the wireless base station unit is capable of an association connection with the downstream node unit via a downstream association wireless bearer (hereinafter referred to as a downstream wireless link) by attaching to a relay wireless communication unit of a downstream node unit, which is another wireless communication unit on the downstream side, and the EPC functional unit includes a communication firmware storage unit that stores communication firmware in which the communication protocol stack is incorporated, and a communication control unit that performs wireless network communication control by executing the communication firmware. a wireless cooperation protocol layer that handles transmission and reception of cooperation notification information, which is notification information used for controlling establishment and management of the cooperation radio bearer between an EPC control unit of the upstream node unit or an EPC control unit of the downstream node unit, is added as a new protocol layer on the upper layer side of the transport layer on the control plane side of the communication protocol stack, and the communication control unit incorporates the cooperation notification information into an cooperation notification packet defined on the wireless cooperation protocol layer, and controls transmission and reception of the cooperation notification information between the upstream node unit or the downstream node unit as transmission and reception control of the cooperation notification packet in accordance with a packet transmission and reception protocol defined on the transport layer, the wireless communication unit being a group of wireless communication units mutually connected by the cooperation radio bearer;
the mobile terminal connected to a first wireless communication unit constituting any one of the plurality of wireless communication units via the terminal wireless bearer, and the mobile terminal connected to a second wireless communication unit constituting any other one of the plurality of wireless communication units via the terminal wireless bearer transmit and receive user data via two or more wireless communication units extending from the first wireless communication unit to the second wireless communication unit and the association wireless bearer mutually connecting the wireless communication units ;
The association notification packet is issued as an IP packet having a fixed destination address that also serves as identification information indicating that the association notification packet is the association notification packet.
A wireless network system comprising:

Images