JP5799716B2 - Relay station, route guidance method, and program - Google Patents

Description

  The present invention relates to a relay station, a route guidance method, and a program in a wireless multi-hop communication system.

  Mobile WiMAX is a technology that applies a wireless communication standard called “WiMAX (Worldwide Interoperability for Microwave Access)” to mobile communication. Currently, in this mobile WiMAX, standardization (IEEE 802.16j) for realizing a multi-hop relay (MMR) is underway.

  Since the frequency band used in WiMAX has high straightness, it is possible to transmit a larger amount of information, but it is difficult to get around obstacles and the transmission range (coverage) is narrow. In order to solve this problem, the multi-hop relay uses a relay station (RS: Relay Station) that can be realized at a lower cost than a base station between a mobile terminal (MS: Mobile Station) and a base station (BS: Base Station). This is a communication method that is installed between the base station and the mobile terminal via a relay station.

  IEEE 802.16j supports the use of nomadic (non-residential) relay stations and mobile relay stations in addition to fixed relay stations. This makes it possible to temporarily expand coverage by installing a nomadic relay station in the event of a disaster or event, or to install a mobile relay station in a train or car. Typically, it is assumed that the operator owns a fixed relay station and the user owns a nomadic relay station.

  In such a wireless multi-hop network, there are a plurality of relay routes. An example of a typical wireless multi-hop network will be described with reference to FIG.

  FIG. 1 shows the configuration of a cell that is within the range of one base station. The cell is composed of relay stations 2-1 and 2-2 and mobile terminals 3-1 to 3-3 for one base station 1. When it is not necessary to distinguish between them, they are simply referred to as relay station 2 and mobile terminal 3 as appropriate. Although the numbers of relay stations 2 and mobile terminals 3 are described as two and three, respectively, the numbers are not limited to this.

  The base station 1, the relay station 2, and the relay station 2 are connected to each other by wireless or wired connection, and the mobile terminal 3 is connected to the base station 1 and the relay station 2 by wireless. Furthermore, the base station 1 is typically connected to another base station 1 (not shown) via a wired network.

In the case of the example illustrated in FIG. 1, for example, the following may be considered as a communication path between the mobile terminal 3-1 and the base station 1.
1) Terminal 3-1 ⇔ Relay station 2-1 ⇔ Base station 1
2) Terminal 3-1 ⇔ Relay station 2-1 ⇔ Relay station 2-2 ⇔ Base station 1
Alternatively, since the mobile terminal 3-1 is at the boundary between relay stations and can communicate with the relay station 2-2 (link shown by a dotted line),
3) Mobile terminal 3-1⇔Relay station 2-2⇔Base station 1
There is also a possible route. Of course, a route in which each mobile terminal directly communicates with the base station is also conceivable.

  In a cellular communication system using such a multi-hop relay scheme, a mobile terminal disclosed in Patent Literature 1 is used to adjust a cell load amount and to relocate a relay station (serving station (with a mobile terminal). In response to a request from a connected base station or relay station, handover is performed to a candidate node. Here, the candidate node includes a base station of an adjacent cell, a relay station of the adjacent cell, a serving base station, and an adjacent relay station of the serving cell. The terminal determines whether to hand over to one of the candidate nodes based on the reception intensity obtained by scanning.

Japanese Patent Application Laid-Open No. 2007-116697

  However, in Patent Document 1, although the mobile terminal is handed over to one of the candidate nodes, the entire route is not switched in consideration of the state of the comprehensive communication route. For example, when the candidate node is a relay station and the reception strength from the relay station is high, a handover is performed to the relay station. However, since the transmission rate with the base station to which the relay station is connected is low, the communication quality of the entire path may be low.

  Further, Patent Document 1 performs a handover process of a relay station for adjusting a load amount of a cell and rearrangement of the relay station, but does not consider maintenance of communication quality. In consideration of the overall state of the communication path between the base station and the mobile terminal, there is a need for a technique for maintaining the connection quality between the base station and the mobile terminal even after the connection is established.

  The present invention has been made in view of such a situation, and in a wireless multi-hop network, suitable for maintaining the quality of connection between a base station and a mobile terminal, a relay station, a route guidance method, and The purpose is to provide a program.

In order to achieve the above object, a relay station according to the first aspect of the present invention provides:
The base station and the mobile terminal are connected directly or via one or more relay stations, the relay station in a wireless multi-hop network system ,
A route guidance unit for guiding the mobile terminal to establish a connection between the base station and the mobile terminal in a predetermined procedure;
For each link constituting a route between the communicable the mobile terminal and previous SL base station of the relay station, and link information collecting section link information is attribute information of the link, collect Jo Tokoro timing ,
The collected link information is different from the collected link information at the time the connection is established, on the basis of the collected link information, from among the path connecting the said mobile terminal and the base station 1 A route selection section for selecting one;
With
The route guidance unit guides the mobile terminal to switch the established connection to the selected route;
It is characterized by that.

Further, the route guidance method according to the second aspect of the present invention includes:
A route guidance method by a relay station in a wireless multi-hop network system , in which a base station and a mobile terminal are connected directly or via one or more relay stations,
The relay station includes a route guidance unit, a link information collection unit, and a route selection unit,
A route guidance step in which the route guidance unit guides the mobile terminal to establish a connection between the base station and the mobile terminal in a predetermined procedure;
The link information collection section for each link constituting a route between the communicable the mobile terminal and previous SL base station of the relay station, the link information is attribute information of the link, in Jo Tokoro timing A link information collection step to collect,
The route selection unit, the collected link information is different from the collected link information at the time the connection is established, on the basis of the collected link information, and the mobile terminal and the base station A route selection step for selecting one of the connecting routes;
The route guidance unit guiding the mobile terminal to switch the established connection to the selected route; and
Comprising
It is characterized by that.

A program according to the third aspect of the present invention is:
A program that causes a computer to function as a relay station in a wireless multi-hop network system , in which a base station and a mobile terminal are connected directly or via one or more relay stations,
The computer,
A route guidance unit for guiding the mobile terminal to establish a connection between the base station and the mobile terminal in response to a request from the mobile terminal;
For each link constituting a route between the communicable the mobile terminal and previous SL base station of the relay station, and link information collecting section link information is attribute information of the link, collect Jo Tokoro timing ,
The collected link information is different from the collected link information at the time the connection is established, on the basis of the collected link information, from among the path connecting the said mobile terminal and the base station 1 A route selection section for selecting one;
To function,
The route guidance unit guides the mobile terminal to switch the established connection to the selected route;
It is characterized by that.

  According to the present invention, it is possible to provide a relay station or the like suitable for maintaining the quality of connection between a base station and a mobile terminal in a wireless multi-hop network.

It is a block diagram which shows the structural example of a general wireless multihop network system. It is a block diagram which shows the structural example of the radio | wireless multihop network system which concerns on this Embodiment. It is a block diagram which shows the structural example of the route guidance type | mold relay station which concerns on this Embodiment. It is a figure which shows the table structural example of a link information database. It is a flowchart which shows the flow of the connection process between the mobile terminal which concerns on this Embodiment, and a base station. It is a figure which shows the path | route between a radio | wireless terminal and a base station. It is a flowchart which shows the flow of the hand-over process to the optimal path | route by the route guidance type | mold relay station which concerns on this Embodiment. It is a figure which shows the change of the state of link information. It is a figure which shows the table structural example of the policy information database which concerns on the modification of this Embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
A wireless multi-hop network system according to the present embodiment is shown in FIG. Compared with the general wireless multi-hop network system shown in FIG. 1, this system has a route guidance type relay station 12 (only one is shown in FIG. 2, but the number is not limited to this), and the relay station 2-1 It has become a configuration that has been replaced.

  The route guidance relay station 12 not only performs wireless multi-hop communication between the base station 1 and the mobile terminals 3-1 to 3-3, but also performs handover, that is, switches the relay station to which the mobile terminal is connected. The mobile terminals 3-1 to 3-3 are guided to a suitable route. Hereinafter, the components of the route guidance relay station 12 will be described with reference to FIG.

  As shown in FIG. 3, the route guidance relay station 12 includes a link information collection unit 21, a route selection unit 22, a route guidance unit 23, a link information database 24, and the like.

  Of the mobile terminals 3 that can communicate with the route guidance type relay station 12, the link information collection unit 21 performs communication between the mobile terminal 3 and the base station 1 for the connection established with the base station 1. Collect link information for the links that make up the route. For example, in the example of FIG. 2, the link information collection unit 21 of the route guidance relay station 12 collects link information for the mobile terminals 3-1 and 3-2 that have established connection with the base station 1. To do. Here, the link information is, for example, at least one of reception strength, BER (Bit Error Rate), transmission rate, communication traffic amount, and the like.

  The link information collection unit 21 monitors the link adjacent to the route guidance relay station 12 and collects link information. On the other hand, for links where the route guidance relay station 12 is not adjacent, each of the nodes adjacent to the link, that is, the base station 1, the relay station 2, another route guidance relay station 12, and the mobile terminal 3, respectively. Is requested to return information on the link adjacent to the node. In response to the request, the other nodes return link information to the link information collection unit 21.

  The link information collection unit 21 collects link information at a predetermined time interval after the mobile terminal 3 capable of communicating with the route guidance type relay station 12 establishes connection with the base station 1, for example.

  When the connection route between the mobile terminal 3 and the base station 1 is determined, the link information database 24 stores the link information of each route existing between the mobile terminal 3 and the base station 1 at that time. Remember. The link information is collected by the link information collection unit 21 as described above. As shown in FIG. 4, the link information database 24 includes the mobile terminal 3 and the base station 1 that are connected to the base station 1 among the mobile terminals 3 that can communicate with the route guidance relay station 12. And a table composed of one or a plurality of records having identification information of each link constituting each route between the link and uplink and downlink link information corresponding to each link.

  Here, uplink link information is link information when data is transmitted from the mobile terminal 3 to the base station 1, and downlink link information is link information when data is transmitted from the base station 1 to the mobile terminal 3. is there. In the example, uplink link information and downlink link information are individually stored and managed, but uplink or downlink link information may be used for the other. That is, uplink link information may be used as downlink link information, or downlink link information may be used as uplink link information.

  When the connection between the base station 1 and the mobile terminal 3 is established, the route selection unit 22 stores the link information stored in the link information database 24 at the time when the connection is established, and the collected links When there is a change in state between the information, a route suitable for the mobile terminal 3 is selected from among the routes between the base station 1 and the mobile terminal 3 based on the collected link information. For example, when a transmission rate is used as link information, a route with the minimum number of hops that achieves the highest transmission rate is selected as the most suitable route. If there are multiple suitable routes, one of them may be selected. The selected route may be the same for the uplink and the downlink or may be different.

  Note that the route selection unit 22 exists between the mobile terminal 3 and the base station 1 when, for example, the mobile terminal 3 moves within or outside the communicable area of the route guidance relay station 12. A process for grasping each of the routes is performed. For example, each node in the cell broadcasts at a predetermined timing and exchanges information about communicable parties with each other, and the route selection unit 22 collects the information to collect the base station 1 and the mobile terminal 3. Grasp the path configuration between The path configuration information is also used when the link information collection unit 21 collects link information.

  The route guidance unit 23 guides the mobile terminal 3 to establish a connection between the base station 1 and the mobile terminal 3 according to a predetermined procedure in response to a request such as a call from the mobile terminal 3. Further, after the connection is established between the base station 1 and the mobile terminal 3, the mobile terminal 3 is guided to switch the connection established to the optimum route selected by the route selection determining unit 22.

  Next, an operation process of the route guidance type relay station 12 according to the present embodiment will be described.

(Establish connection)
First, for example, when the mobile terminal 3 calls (calls) another mobile terminal 3, connection processing is started between the mobile terminal 3 and the base station 1. A flow of connection processing will be described with reference to FIG.

  In the connection process, the mobile terminal 3 first scans a channel of defined frequencies, and among the nodes (route-guided relay 12, relay station 2, or base station 1) constituting the cell to which the mobile terminal 3 belongs. , One that can communicate with the strongest reception strength is selected (step S101). Then, connection processing is performed with the selected node (step S102a if the selected node is the route guidance type relay station 12 or relay station 2, and S102b if the selected node is the base station 1). Here, the connection processing includes, for example, ranging and parameter negotiation.

  Similarly, the node (other than the base station 1) that has performed connection processing with the mobile terminal 3 selects a node that can communicate with the strongest reception strength among the links adjacent to the mobile terminal 3 (step S104). (S105a if the selected node is the base station 1, step S105b if the selected node is the route guidance relay station 12 or the relay station 2). Here, in the route guidance type relay station 12, the route guidance unit 23 performs connection processing. Note that the processing in step S103 indicates processing when the route guidance relay station 12 or the relay station 2 is selected from another route guidance relay station 12 or the relay station 2 and performs connection processing. .

  When the connection is established up to the base station 1, the base station 1 is in charge of the area where the mobile terminal 3 (not shown) of the call destination (the receiving side) is located (ie, the serving base station, not shown). And a predetermined process are performed to establish a connection to the called mobile terminal 3 (step S106). As a result, communication is possible between the mobile terminals 3 on the calling side and the incoming side, but in the present embodiment, only the connection from the mobile terminal 3 to the base station 1 will be described.

  Here, the above processing will be described using the wireless multi-hop network system shown in FIG. 6 having the same configuration as that shown in FIG. However, in order to facilitate understanding, only 3-1 of the mobile terminal 3 is shown.

  For example, in FIG. 6, when the reception strength of the signal from the route guidance relay station 12 is stronger than that of the relay station 2-2, the mobile terminal 3-1 first selects the link 3 and then performs the route guidance relay. In order to establish a connection with the station 12, the connection request is transferred to the route guidance type relay station 12. Similarly, when it is determined that the reception strength from the base station 1 is stronger than the relay station 2-2, the route guidance type relay 12 selects the link 4 and transfers the connection request to the base station 1.

  In FIG. 6, a solid line indicates a connected link, and a dotted line indicates other links. That is, the path 1 composed of the link 3 and the link 4 is connected. In the case of call processing, the connection destination node may be selected from the base station 1 to the mobile terminal 3-1 by selecting the connection destination node in the reverse procedure. Further, as a route selection criterion for establishing a connection, other than the reception strength may be used, and the route selection method is not limited to the above.

  Returning to FIG. 5, when the connection with the receiving-side mobile terminal 3 is successfully established, a response arrives at the calling-side mobile terminal 3 from the serving base station of the receiving-side mobile terminal 3. On the other hand, the calling-side mobile terminal 3 is connected to the route guidance relay station 12 in consideration of the case where the communication-guided route guidance relay station 12 is not included in the connection route. Notify that it has been established. When the link information collection unit 21 of the route guidance type relay station 12 receives the notification, the link (connected link) configuring each route existing between the mobile terminal 3 on the calling side and the base station 1 at that time. Link information is collected and stored in the link information database 24 (step S107).

  The link information collection unit 21 collects link information by monitoring the link adjacent to the route guidance relay station 12 among the links constituting the route. On the other hand, among the links, the link that is not adjacent to the route guidance relay station 12 is a node adjacent to the link, that is, the base station 1, the relay station 2, the other route guidance relay station 12, and the movement. Each terminal 3 is requested to return information on the link adjacent to the node, and link information is received from each node. The collected link information is stored in the link information database 24.

  For example, in FIG. 6, link information of link 1 to link 5 is collected for the mobile terminal 3-1. When the link information collection unit 21 collects link information between the mobile terminal 3-1 and the base station 1, the link information about the link 2 is performed from the relay station 2-2 or the mobile terminal 3-1. However, other links are collected by themselves because they are adjacent.

(Handover processing to the optimal route)
Next, the process of the path mobile relay station 12 for handing over to the optimum path after the connection is established will be described with reference to the flowchart of FIG.

  First, when a predetermined time elapses (step S201; YES), the link information collection unit 21 links links that configure each path existing between each of the mobile terminals 3 to which connection is established and the base station 1. Information is collected (step S202). While the predetermined time has not elapsed (step S201; NO), the process of step S201 is repeated and waited. That is, collection of link information is performed periodically. In the process of step S202, the procedure for collecting link information is the same as the procedure described in the process of step S107.

  Next, the route selection unit 22 compares the link information stored in the link information database 24 with the collected link information (step S203). If there is no change in the link information (step S203; NO), the process is terminated. On the other hand, when link information has changed (step S203; YES), the route selection unit 22 selects a route suitable for the mobile terminal 3-1 based on the collected link information (step S204).

  For example, a link information table as shown in FIG. 8A is stored in the link information database 24 as link information of the link between the mobile terminal 3-1 and the base station 1 by executing the process of step S 107. Has been. Further, link information shown in FIG. 8B is collected for the link between the mobile terminal 3-1 and the base station 1 by executing the process of step S <b> 202. In FIGS. 8A and 8B, a transmission rate is used as link information.

  Comparing FIG. 8 (A) and FIG. 8 (B), the state of the link 4 is changed due to the deterioration of the radio wave condition or the like. The route selection unit 22 of the route guidance type relay station 12 selects a route having the minimum number of hops that realizes the highest transmission rate suitable for the mobile terminal 3-1, based on the link information collected in the process of step S202. Calculate as route 2.

  That is, the transmission rate of the entire route is shifted to the link having the lowest transmission rate in the route. Therefore, the transmission rate of the path 1 composed of the link 3 and the link 4 is 10 Mbps in the state shown in FIG. 8B. On the other hand, in the path 2 composed of the link 1 and the link 2, the transmission rate is 15 Mbps. Therefore, the route with the minimum number of hops that achieves the highest transmission rate is route 2. In the example of FIG. 8, the uplink and downlink transmission rates are the same, but if they are different, an optimum route may be selected according to the communication direction.

  Returning to FIG. 7, the route guiding unit 23 makes a handover request to the base station 1 to switch the connection path to the route 2 (step S205). In response to the request, the base station 1 starts a handover process, and executes a process of switching the connection path between the mobile terminal 3-1 and the base station 1 to the route 2. In this way, the link 4 can be switched to a path that achieves the highest transmission rate as a whole, instead of simply switching to the link 5 having a higher transmission rate.

  The handover process may be requested by the mobile terminal 3-1, and performed by the mobile terminal 3-1. Alternatively, the route guidance relay station 12 may perform the initiative. Further, after the handover process is completed, the link information collection unit 21 stores the link information collected in the process of step S202 in the link information database (step S206). Then, the process returns to step S201. In the process of step S203 in the next loop, the stored link information and the newly collected link information are compared, and it is determined whether or not the route state has changed.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment mentioned above, A various deformation | transformation and application are possible. Moreover, it is also possible to freely combine the constituent elements of the above-described embodiments.

  In the above embodiment, the route selection unit 22 selects the route based on only the link information with the base station 1 for the mobile terminal 3 to which the route guidance type relay station 12 guides the route. . However, the present invention is not limited to this. For example, each mobile terminal 3, a user who uses each mobile terminal 3, and a policy composed of one or a plurality of records having three items of policy information corresponding to each user. The information table may be stored in the link information database 24. In this case, the policy information may be set in advance by the user, or may be set by the operator according to the state of the mobile terminal 3 of the user. The route selection unit 22 may select a route based on the policy information in addition to the link information.

  As policy information, for example, as shown in FIG. 9, “radio throughput emphasis” indicating that emphasis is placed on improving the throughput of the user as much as possible, and when the remaining battery level is low, It is only necessary to be able to set “power saving emphasis” or the like indicating that importance is placed on connecting to a good base station 1 or relay station 2 to suppress power consumption. For example, when “emphasis on power saving” is set, the route selection unit 22 selects a route from the mobile terminal 3 to the base station 1 or the relay station 2 that has a good radio wave condition in the vicinity as a suitable route. Thereby, the route guidance type relay station 12 can select a route suitable for the user of the mobile terminal 3.

  Moreover, in the said embodiment, when establishing the connection between the mobile terminal 3 and the base station 1, it was set as the structure which selects the node which can obtain the highest receiving intensity sequentially as a connection destination. The link information collection unit 21 is not limited to this. For example, the link information collection unit 21 periodically and not only establishes the connection but also periodically establishes the mobile terminal 3 and the base station 1 for all the mobile terminals 3 that can communicate with the route guidance relay station 12. Link information of the route between the mobile terminal 3 and the route selection unit 22 may select a route suitable for the mobile terminal 3 as in step S204. Then, the route guiding unit 23 may guide the mobile terminal 3 so that the connection is made through the selected route. As a result, it is possible to select an optimum route when establishing a connection.

  Moreover, although the case where the transmission rate is used as the link information has been described in the above embodiment, other parameters may be used as the link information.

  In addition to WiMAX, this route guidance type relay station is a wireless multi-hop in mobile networks such as 3GPP (Third Generation Partnership Project) / 3GPP2 (Third Generation Partnership Project 2) and 4th generation mobile communication system (IMT-Advanced). The present invention can also be applied to a system using a communication method.

  The route guidance relay station 12 can be realized as dedicated hardware, or may be realized by causing a general computer having a wireless interface to execute a control program for the route guidance relay station 12, for example. . The control program for the route guidance relay station 12 may be stored in advance in a storage unit of a computer, or may be a flexible disk, a CD-ROM (Compact Disk Read-Only Memory), a DVD (Digital Versatile Disk). The program may be distributed by being stored in an MO (Magneto-Optical disk), a USB memory, or the like. In the latter case, the computer may be provided with a device that reads one of the storage media to be used, and the computer may be configured to read the program so as to execute the above-described processing operation.

  A part or all of the above-described embodiment can be described as in the following supplementary notes, but is not limited thereto.

(Appendix 1)
The base station and the mobile terminal are connected directly or through one or more relay stations, the relay station in a wireless multi-hop network,
A route guidance unit for guiding the mobile terminal to establish a connection between the base station and the mobile terminal in a predetermined procedure;
For each link constituting a route between the mobile terminal that can communicate with the relay station and the base station, link information that is attribute information of the link is connected to the mobile terminal and the base station. Link information collection unit that collects at a predetermined timing from the established time point,
If the collected link information is different from the link information collected at the time when the connection is established, one of the paths connecting the base station and the mobile terminal is selected based on the collected link information. A route selection section for selecting one;
With
The route guidance unit guides the mobile terminal to switch the established connection to the selected route;
A relay station characterized by that.

(Appendix 2)
The link information collection unit collects link information at a predetermined timing even before connection is established,
The route guidance unit guides the mobile terminal to establish a connection between the base station and the mobile terminal based on the collected link information.
The relay station according to Supplementary Note 1, wherein

(Appendix 3)
The route selection unit of the relay station selects one of routes connecting the base station and the mobile terminal based on at least one of the link information and a preset user request. select,
The relay station according to Supplementary Note 1, wherein

(Appendix 4)
The route guidance unit of the relay station performs a handover on its initiative, or requests a handover to the base station or the mobile terminal,
The relay station according to appendix 1 or 2, characterized in that.

(Appendix 5)
A route guidance method by a relay station in a wireless multi-hop network, in which a base station and a mobile terminal are connected directly or via one or more relay stations,
The relay station includes a route guidance unit, a link information collection unit, and a route selection unit,
A route guidance step in which the route guidance unit guides the mobile terminal to establish a connection between the base station and the mobile terminal in a predetermined procedure;
The link information collection unit establishes a connection with link information, which is attribute information of the link, for each link constituting a route between the mobile station capable of communicating with the relay station and the base station. Link information collection step to collect at a predetermined timing from the time,
When the collected link information is different from the link information collected at the time when the connection is established, the route selection unit determines whether the base station and the mobile terminal are based on the collected link information. A route selection step for selecting one of the connecting routes;
The route guidance unit guiding the mobile terminal to switch the established connection to the selected route; and
Comprising
A route guidance method characterized by that.

(Appendix 6)
A program that causes a computer to function as a relay station in a wireless multi-hop network, in which a base station and a mobile terminal are connected directly or via one or more relay stations,
The computer,
A route guidance unit for guiding the mobile terminal to establish a connection between the base station and the mobile terminal in response to a request from the mobile terminal;
For each link constituting a route between the mobile terminal capable of communicating with the relay station and the base station, link information, which is attribute information of the link, is determined at a predetermined timing from the time when the connection is established. A link information collection unit to collect,
If the collected link information is different from the link information collected at the time when the connection is established, one of the paths connecting the base station and the mobile terminal is selected based on the collected link information. A route selection section for selecting one;
To function,
The route guidance unit guides the mobile terminal to switch the established connection to the selected route;
A program characterized by that.

DESCRIPTION OF SYMBOLS 1 Base station 2 Relay station 3 Mobile terminal 12 Route guidance type relay station 21 Link information collection part 22 Path selection part 23 Route guidance part 24 Link information database

Claims (7)

The base station and the mobile terminal are connected directly or via one or more relay stations, the relay station in a wireless multi-hop network system ,
A route guidance unit for guiding the mobile terminal to establish a connection between the base station and the mobile terminal in a predetermined procedure;
For each link constituting a route between the communicable the mobile terminal and previous SL base station of the relay station, and link information collecting section link information is attribute information of the link, collect Jo Tokoro timing ,
The collected link information is different from the collected link information at the time the connection is established, on the basis of the collected link information, from among the path connecting the said mobile terminal and the base station 1 A route selection section for selecting one;
With
The route guidance unit guides the mobile terminal to switch the established connection to the selected route;
A relay station characterized by that. The route selection unit of the relay station selects one of routes connecting the base station and the mobile terminal based on at least one of the link information and a preset user request. select,
The relay station according to claim 1. The route guidance unit of the relay station performs a handover on its initiative, or requests a handover to the base station or the mobile terminal,
The relay station according to claim 1 or 2. The route selection unit selects one of the routes connecting the base station and the mobile terminal regardless of whether the relay station is included in the route used at that time,
The route guidance unit performs a handover or requests a handover from the base station or the mobile terminal regardless of whether the relay station is included in the route selected by the route selection unit. ,
The relay station according to claim 1, wherein the relay station is a relay station. The relay station according to any one of claims 1 to 4,
A relay station that does not perform route guidance;
A wireless multi-hop network system. A route guidance method by a relay station in a wireless multi-hop network system , in which a base station and a mobile terminal are connected directly or via one or more relay stations,
The relay station includes a route guidance unit, a link information collection unit, and a route selection unit,
A route guidance step in which the route guidance unit guides the mobile terminal to establish a connection between the base station and the mobile terminal in a predetermined procedure;
The link information collection section for each link constituting a route between the communicable the mobile terminal and previous SL base station of the relay station, the link information is attribute information of the link, in Jo Tokoro timing A link information collection step to collect,
The route selection unit, the collected link information is different from the collected link information at the time the connection is established, on the basis of the collected link information, and the mobile terminal and the base station A route selection step for selecting one of the connecting routes;
The route guidance unit guiding the mobile terminal to switch the established connection to the selected route; and
Comprising
A route guidance method characterized by that. A program that causes a computer to function as a relay station in a wireless multi-hop network system , in which a base station and a mobile terminal are connected directly or via one or more relay stations,
The computer,
A route guidance unit for guiding the mobile terminal to establish a connection between the base station and the mobile terminal in response to a request from the mobile terminal;
For each link constituting a route between the communicable the mobile terminal and previous SL base station of the relay station, and link information collecting section link information is attribute information of the link, collect Jo Tokoro timing ,
The collected link information is different from the collected link information at the time the connection is established, on the basis of the collected link information, from among the path connecting the said mobile terminal and the base station 1 A route selection section for selecting one;
To function,
The route guidance unit guides the mobile terminal to switch the established connection to the selected route;
A program characterized by that.

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