JP7405530B2 - Relay device, control method, and program for transferring routed signals - Google Patents

Description

The present invention relates to relay communication control technology for transferring routed signals.

The 3rd Generation Partnership Project (3GPP) is currently developing the NR (New Radio) standard, which is a 5th generation (5G) cellular communication standard. Further, in the NR standard, IAB (Integrated Access and Backhaul) is being considered as a technology for executing communication on a backhaul line using radio resources for a base station device to communicate with a terminal device. In IAB, for example, the line between a 5G base station device (IAB donor) directly connected to the core network and a relay device (IAB node) that provides wireless access to terminal devices, or the line between IAB nodes is wireless. established by. The IAB donor manages the IAB nodes that are directly or indirectly connected to its own device, and can recognize which IAB node a terminal device that is not directly connected to its own device is connected to. . Then, the IAB donor sends, for example, a packet containing data addressed to the terminal device to the IAB node to which the terminal device is connected, and the IAB node sends a wireless signal containing the data to the terminal device. Make it. Multiple routes may be set up from the IAB donor to the IAB node.

FIG. 1 shows an example of a wireless communication system using IAB. In the example of FIG. 1, for example, a 5G base station device 101 connected to the core network, a relay device A102 that can be directly connected to the base station device 101, and a relay device A102 that is connected to the base station device 101 at least through the relay device A102. There are relay devices B103 to F107. In one example, the base station device 101 is an IAB donor, and the relay device is an IAB node. For example, when communicating with the terminal device 111, the base station device 101 transfers packets in this order from the base station device 101 to the relay device A102, from the relay device A102 to the relay device B103, and from the relay device B103 to the relay device B103. A wireless signal containing data is transmitted to the terminal device 111. Similarly, a wireless signal transmitted from the terminal device 111 is received by the relay device B103, and a packet containing the data is transmitted to the base station device 101 via the relay device A102. A plurality of routes can be set between the base station device 101 and one relay device. For example, the route between the base station device 101 and the relay device F107 is [Relay device A102, Relay device B103, Three routes are set: a route via [relay device D105], a route via [relay device A102, relay device C104, relay device D105], and a route via [relay device A102, relay device C104, relay device E106]. It is possible.

If multiple routes can be set, the base station device identifies a relay device that directly communicates with the terminal device, and then determines the route to be used with that relay device. For example, the route to be used is determined based on a predetermined criterion such as equalizing the load on multiple routes. Non-Patent Document 1 states that the relayed packet contains identification information of the relay destination node (for example, a base station device in the uplink, and a relay device that directly communicates with the terminal device in the downlink) and the route to be used. It is stated that identification information is included. According to this, each relay device can recognize to which node the received packet should be transferred based on the route identification information.

3GPP contribution, R2-1908363, May 2019

It is assumed that communication may not be possible on part of the relay route. For example, the wireless quality between relay device A 102 and relay device B 103 in FIG. 1 may deteriorate, making it impossible to continue communication. In this case, the relay device A 102 cannot transmit the packet containing the identification information of the route passing through the relay device B 103 received from the base station device 101 to the relay device B 103, and the packet transfer fails. sell.

The present invention provides a technique for appropriately transferring signals to a destination in communication using a relay transmission path.

A relay device according to one aspect of the present invention is a relay device that relays a signal from a base station device or a terminal device to a destination device , and includes a receiving means for receiving the signal , and a receiving device for transmitting data included in the received signal. If it is not possible to specify the transfer destination of the signal based on the route identification information included in the received signal , the relay device and determining means for determining a device with which a connection has been established as a device to which the signal is to be transferred.

According to the present invention, it is possible to appropriately transfer a signal to a destination in communication using a relay transmission path.

1 is a diagram illustrating a configuration example of a wireless communication system. FIG. 2 is a diagram illustrating an example of a hardware configuration of a relay device. FIG. 3 is a diagram showing an example of a functional configuration of a relay device. FIG. 3 is a diagram illustrating an example of the flow of processing executed by a relay device.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the claimed invention, and not all combinations of features described in the embodiments are essential to the invention. Two or more features among the plurality of features described in the embodiments may be arbitrarily combined. In addition, the same or similar configurations are given the same reference numerals, and duplicate explanations will be omitted.

(System configuration)
The wireless communication system of this embodiment has a configuration as shown in FIG. 1 described above. In this system, as described above, communication between the base station device 101 (IAB donor) and the terminal devices 111 to 112 can be performed through a relay path including one or more relay devices (IAB nodes). A plurality of relay routes can be set, and the base station device can determine which route to use for communication. For example, as described above, between the base station device 101 and the relay device F107, the first route via [relay device A102, relay device B103, relay device D105], [relay device A102, relay device C104, relay device Three routes can be set: a second route via [device D105], and a third route via [relay device A102, relay device C104, relay device E106]. For example, the base station device 101 decides to perform communication with the terminal device 112 via the relay device F107, and further changes the route between the base station device 101 and the relay device F107 to one of the three routes described above. Choose from among them.

Note that a new route may be created, for example, when a base station device establishes a connection with a newly installed relay device, or when a relay device establishes a connection with another newly installed relay device. Set. For example, when the relay device F107 is newly installed and the connection with the relay device E106 is established, the relay device F107 is The route leading to is set. In addition, in response to the establishment of the connection between the relay device F107 and the relay device D105, the connection is made from the base station device 101 to the relay device F107 via [the relay device A102, the relay device B103, and the relay device D105]. A route and a route leading to relay device F107 via [relay device A102, relay device C104, and relay device D105] are set. Note that when a route is set, the identification information of the route is notified to the relay devices included in the route. The identification information is associated with information that identifies the devices included in the corresponding route and information that indicates the order in which signals should be transferred between those devices. is memorized. Each relay device can specify a device to which a signal is to be transferred (for example, another relay device or a base station device) based on the identification information. Note that "transfer" here may also be a non-regenerative relay that amplifies the received signal as it is and transmits it to another device, but in the following, it is used to decode the received signal and extract the data. It is assumed that regenerative relay is used in which a transmission signal is generated from data and transmitted to a transfer destination device. Further, "transferring a signal" refers to transferring data included within the signal, and as described below, header information such as route identification information may be changed.

Note that when a plurality of lines are established between two relay devices, the route identification information may include information for specifying the lines between the relay devices. For example, if two lines, line α and line β, are established between relay device A 102 and relay device B 103, information specifying the line to be used (line α or line β) is included in the route identification information. can include.

As an example, in this embodiment, it is assumed that the base station device 101 communicates with the terminal device 112, and in order to perform this communication, the first route via [relay device A102, relay device B103, relay device D105] is selected. It shall be assumed that In this case, a signal transmitted from the base station device 101 to the terminal device 112 is first transmitted to the relay device A102, and the relay device A102 receives the signal and transfers it to the relay device B103. Thereafter, relay device B103 transfers the signal received from relay device A102 to relay device D105, and relay device D105 transfers the signal received from relay device B103 to relay device F107. Then, the relay device F107 transmits the data included in the received signal to the terminal device 112. Note that, in one example, communication between the base station device and the relay device, communication between the relay devices, and communication between the relay device and the terminal device are performed wirelessly.

Note that although an example in which the base station device 101 communicates with a terminal device via a plurality of relay devices will be described below, the base station device 101 may communicate with a terminal device through a single relay device or without using a relay device. , it is also naturally possible to communicate with a terminal device.

When the base station device 101 transmits a signal through the above-mentioned first route, the first identification information indicating the relay device F107 that directly communicates with the terminal device 112 as the destination is added to the signal, and the signal is transferred. and second identification information indicating the first route which is the desired route. Then, when the relay device included in the first route determines that the relay device is the destination by checking the first identification information, the relay device determines that the relay device is the destination device based on the information of the terminal device included in the transferred signal. , transmits a wireless signal containing the transferred data to the terminal device. Further, when the relay device determines that the relay device is not the destination by checking the first identification information, the relay device identifies the device to which the signal is transferred based on the second identification information. For example, in the first route described above, when relay device B103 receives a signal from relay device A102, it checks the first identification information included in the signal and determines whether the relay device B103 is the destination (relay device F107). It is determined that there is no. Then, relay device B103 identifies relay device D105 as a transfer destination device based on the second identification information indicating the first route, and transfers the received signal to relay device D105. Further, in the first route, when the relay device B103 receives a signal from the relay device D105, it checks the first identification information included in the signal and confirms that the relay device B103 is not the destination (base station device 101). It is determined that Then, relay device B103 identifies relay device A102 as a transfer destination device based on the second identification information indicating the first route, and transfers the received signal to relay device A102. In this way, communication between the base station device 101 and the terminal device can be performed using a relay route.

Here, for example, when the base station device 101 transmits a signal including first identification information indicating the relay device F107 and second identification information indicating the first route to the relay device A102, the relay device Assume that a situation has occurred in which A102 cannot transfer the signal to relay device B103. For example, if RLF (Radio Link Failure) occurs in the wireless link between relay device A 102 and relay device B 103, or if the load on that wireless link becomes high and communication with sufficient quality is no longer possible. This condition can occur. At this time, the relay device A 102 can notify the base station device 101 that the first route cannot be used, and can notify that another route should be used. Then, the base station device 101 can retransmit the signal using, for example, the above-described second route or third route that does not use the wireless link between the relay device A 102 and the relay device B 103. On the other hand, for example, if it is determined that a wireless link cannot be used in a relay device near the destination on a route that is in use, and the base station device 101 is notified that the route is unusable, a signal is sent to indicate that the wireless link is unavailable. In addition to the time it takes for the notification to reach the unavailable relay device, it takes time for the notification to reach the base station device 101, and the time it takes for the signal to be transmitted via a different route can become long.

Therefore, in this embodiment, in addition to or in place of the above notification, the relay device transfers the signal to another destination to prevent communication delays caused by the signal being transmitted via a different route. Do it like this. For example, when relay device A102 determines that the wireless link with relay device B103 cannot be used, the signal is transferred to relay device C104 instead of relay device B103. However, in this case, since the relay device C104 does not include its own device in the route specified by the second identification information included in the received signal, the relay device C104 determines the transfer destination device based on this second identification information. Can not do it.

Therefore, in this embodiment, if the relay device does not include the relay device in the route indicated by the second identification information included in the received signal, the relay device determines a specific device as the device to which the signal is transferred. . For example, the relay device C104 determines either the relay device D105 or the relay device E106, with which it has established a connection, as the transfer destination device. For example, the relay device C104 selects a route leading to the relay device F107 based on the first identification information based on the route information stored in itself, and the relay device C104 transmits the signal on that route. The device to be transferred can be determined as the destination device.

Furthermore, the base station device 101 may preset whether or not the relay device C104 can determine the transfer destination device. In this case, the relay device C104 can determine the device to which the received signal is to be transferred, or can discard the received signal without forwarding the received signal, according to the preset settings.

The relay device C104 may determine a predetermined transfer destination device as the specific device. In one example, the relay device C104 selects one of the devices as a predetermined transfer destination device in response to a state in which there are multiple devices that are candidate transfer destinations for transmitting the signal from the base station device 101. Set in advance. For example, in response to establishing a connection with each of the relay device D105 and the relay device E106 (for example, in response to starting Dual Connectivity), the relay device C104 connects one of the devices (for example, the relay device D105) to It can be preset as a predetermined transfer destination device. Which device is to be the predetermined transfer destination device is determined, for example, according to an instruction from the base station device 101. Note that the relay device C104 may determine a predetermined transfer destination device without depending on the instruction from the base station device 101. Further, it is not necessary that there is only one predetermined transfer destination device, and a plurality of predetermined transfer destination devices may be set in advance. At this time, the relay device C104 may hold information that assigns priorities to each of a plurality of predetermined transfer destination devices. Then, the relay device C104 actually performs the transfer based on the priority order from among the devices included in the route reachable to the destination indicated by the first identification information and included in the predetermined transfer destination devices, for example. The specific equipment to do so may be determined. For example, the relay device C104 can determine the device with the highest priority among the predetermined transfer destination devices as the specific device. Further, the relay device C104 may, for example, determine a device having a higher priority than a predetermined priority among the predetermined transfer destination devices as the specific device.

Note that even if the relay device C104 does not include the route indicated by the second identification information included in the received signal, the relay device C104 determines that a device to which the relay device can transmit a signal is included. There are cases where it is possible. For example, since the above-mentioned first path includes the relay device D105 and the relay device C104 has established a connection with the relay device D105, in this case, the relay device C104 connects the relay device D105 to a specific It can be determined as a device. Note that when executing such processing, the base station device 101 provides each relay device with identification information about all routes connecting the base station device and other devices and information indicating devices included in the routes. May be notified. In addition, the base station device 101 identifies routes for each relay device, for all routes including that relay device, as well as all routes including other relay devices connected to that relay device. Information and information indicating devices included in the route may be notified. As a result, when each relay device receives a signal that includes second identification information regarding a route that does not include the relay device, it has established a connection with the relay device itself, and the second identification information If there is a device included in the path indicated by , the signal can be transferred to that device. Note that the relay device can limit the devices that can be selected as the transfer destination depending on whether the signal is an uplink signal or a downlink signal. That is, for example, when relay device C104 receives a downlink signal from relay device A102, other devices existing in the uplink direction, such as relay device A102, can be excluded from candidates for selection of a specific device. Thereby, it is possible to prevent the signal from not reaching the terminal device due to the signal being transferred back to the device from which the signal was sent. In addition, at this time, if the base station device 101 or the relay device F107 (signal transmission destination) is specified as the destination that is the first identification information, the relay device C104 uses the first identification information. Then, it is possible to determine whether the signal is an uplink signal or a downlink signal. There may also be an embodiment in which the relay device C104 determines whether the signal is an uplink signal or a downlink signal based on the route indicated by the second identification information.

The relay device C104 also communicates with multiple devices to which the signal is transferred in the direction opposite to the direction in which the signal is transmitted (that is, if the signal is a downlink signal, uplink communication; A specific device to which a signal is transferred may be determined depending on the frequency of use of each route in downlink communication (in the case of a link signal). In other words, a route that is frequently used in communication on a link in the opposite direction to the direction in which the signal is transferred can be considered to have good radio link conditions such as radio quality, so such a route is used. As such, a specific device may be determined. For example, the relay device C104 determines the first usage frequency of the route from the relay device F107 to the relay device C104 via the relay device D105, and the first frequency of use of the route from the relay device F107 to the relay device C104 via the relay device E106. and the second frequency of use. Then, if the first frequency of use is higher, the relay device C104 determines the relay device D105 as a specific device, and if the second frequency of use is higher, the relay device C104 determines the relay device E106 as a specific device. It can be determined as a device. Note that if the magnitude of the difference between the first frequency of use and the second frequency of use is less than or equal to a predetermined value, the relay device C104 determines, for example, a predetermined transfer destination device as a specific device. You may.

Note that if the relay device C104 does not include the own device in the route indicated by the second identification information included in the received signal, the relay device C104 transfers the signal as described above, and also transfers the signal to the base station device 101 or the relay device F107. (the source of the signal) may be notified that the route is unavailable. Through this notification, the relay device C104 can prompt the device that is the source of the signal to communicate using another route.

Further, the period during which the relay device C104 transfers the signal may be limited to a certain period after the communication to the transmission source device. In this case, after the fixed period has expired, the relay device C104 does not determine the transfer destination device, and if the relay device C104 is not included in the route indicated by the second identification information included in the received signal, the relay device C104 does not determine the destination device. It may be discarded without transmitting the signal.

Note that the relay device C104 may change the second identification information included in the received signal when the relay device C104 does not include the relay device in the route indicated by the second identification information included in the received signal. For example, the relay device C104 can replace the second identification information included in the signal with identification information corresponding to a route that includes the device to which the signal is transferred. Thereby, the device that has received the signal from the relay device C104 can determine the destination of the signal based on the replaced identification information. For example, upon receiving a signal including the second identification information corresponding to the first route described above, the relay device C104 determines the transfer destination device as described above. Then, the relay device C104 replaces the second identification information included in the received signal with the identification information corresponding to the route including the transfer destination device. For example, when the relay device D105 is the transfer destination device, the relay device C104 uses the above-mentioned second path identification information, and when the relay device E106 is the transfer destination device, the relay device C104 uses the above-mentioned third path. The second identification information is replaced by the identification information corresponding to the route. Thereby, relay device D105 or relay device E106 that has received the signal transfer can decide to transfer the signal to relay device F107 based on the replaced identification information. Note that when the relay device C104 uses the relay device D105 as the transfer destination device, the relay device C104 may leave the second identification information corresponding to the first route unchanged. That is, the first route does not include the relay device C104 but includes the relay device D105, so if the relay device D105 is the transfer destination, the second identification information may be left as is. According to this, the signal transfer after the relay device D105 can be performed using the route set by the base station device 101 as is.

Further, the relay device C104 may replace the second identification information with predetermined information, for example. This predetermined information may be information indicating that a route used for signal transfer is not specified. Note that the relay device C104 may delete the second identification information instead of replacing the second identification information with predetermined information. That is, by not including the second identification information, it may be implicitly indicated that the route is not specified. In these cases, the relay device that has received the signal transferred by the relay device C104 cannot specify the destination of the signal based on the second identification information, so as explained with focus on the above-mentioned relay device C104. , determines the transfer destination device, and transfers the signal to the determined transfer destination device.

Note that in the above example, an example was described in which the relay device C104 changes the second identification information when the relay device C104 does not include the relay device in the route indicated by the second identification information included in the received signal. , but not limited to this. That is, in the above example, because the relay device A 102 transmits the signal to the relay device C 104 without transmitting the signal to the relay device B 103 to which the signal should originally be transferred, the relay device C 104 transfers the signal to a route that does not include the own device. A signal containing second identification information corresponding to the second identification information is received. On the other hand, the second identification information may be changed when the relay device A 102 determines the signal transfer destination without depending on the route indicated by the second identification information. This change may be the replacement of the second identification information with predetermined information or the deletion of the second identification information, as in the case described above. In this case, when the relay device C104 receives the signal transferred by the relay device A102, the relay device C104 cannot identify the signal transfer destination using the second identification information, so it determines the transfer destination device as described above. , transfers the signal to the determined transfer destination device. Further, the relay device A102 may replace the second identification information with identification information corresponding to a route including the relay device C104, which is the signal transfer destination. In this case, when the relay device C104 receives the signal transferred by the relay device A102, the relay device C104 can identify the route that includes the device using the second identification information, so the relay device C104 can determine the destination of the signal according to that route. can be determined. Note that the relay device A102 has established a wireless link with the relay device D105 included in the first route indicated by the second identification information, and has decided to transfer the signal directly to the relay device D105. In some cases, the signal may be transferred without changing the second identification information.

Note that the relay device C104 determines the device to which the signal is to be transferred, and when multiple lines are established with the device to which the signal is transferred, the relay device C104 selects the line to be used for transfer, for example, among the available lines. It can be determined by randomly selecting from Note that the selection of the line used for transfer is based on predetermined settings and rules, high line quality (QoS), low load (few nodes or UEs in use, or wireless It may also be based on (low resource utilization).

Although the above explanation focused on the relay device A102 and the relay device C104, all the relay devices execute both the process executed by the relay device A102 and the process executed by the relay device C104. It can be configured as possible.

(Device configuration)
Next, an example of a hardware configuration of a relay device that executes the above-described processing will be described using FIG. 2. These devices include, in one example, a processor 201, a ROM 202, a RAM 203, a storage device 204, and a communication circuit 205. The processor 201 is a computer that includes one or more processing circuits such as a general-purpose CPU (central processing unit) or an ASIC (application-specific integrated circuit), and is stored in a ROM 202 or a storage device 204. By reading and executing the program, the overall processing of the relay device and each of the above-mentioned processing are executed. The ROM 202 is a read-only memory that stores information such as programs and various parameters related to processing executed by the relay device. The RAM 203 is a random access memory that functions as a work space when the processor 201 executes a program and also stores temporary information. The storage device 204 is configured by, for example, a removable external storage device. The communication circuit 205 is configured by, for example, a circuit for wireless communication. The relay device is configured to include, for example, a baseband circuit for cellular communication, an RF circuit, and an antenna as a communication circuit 205 for communicating with a base station device, other relay devices, and terminal devices. Note that the communication circuit 205 of the relay device may include, for example, a circuit for performing wireless or wired communication for transmitting control signals and the like. Note that although one communication circuit 205 is illustrated in FIG. 2, each device may have a plurality of communication circuits.

FIG. 3 shows an example of the functional configuration of the relay device. The relay device includes, for example, a communication section 301, a route information specifying section 302, a transfer destination determining section 303, and a transfer control section 304. Further, the relay device may include a route information change unit 305 and a transfer destination change notification unit 306. Note that these functional units can be realized, for example, by the processor 201 executing a program stored in the ROM 202.

The communication unit 301 is a functional unit for performing wireless communication with a base station device, other relay devices, and terminal devices in accordance with cellular communication standards. The route information specifying unit 302 specifies a route to which a signal received from a base station device or another relay device should be transferred based on identification information included in the signal. The transfer destination determining unit 303 determines the device to which the signal is transferred based on the route specified by the route information specifying unit 302. For example, if the device itself is included in the specified route, the transfer destination determining unit 303 specifies the device to which the signal should be transferred next on that route. Note that the transfer destination determination unit 303 determines to transfer the signal to a device different from the transfer destination device when communication via a wireless link with the transfer destination device determined according to the specified route is not possible. You may. Further, if the own device is not included in the specified route, the transfer destination determining unit 303 can determine a specific device as the transfer destination device. Note that the method for determining a specific device is as described above, so the description will not be repeated here. The transfer control unit 304 controls the communication unit 301 to transfer the received signal to the transfer destination device determined by the transfer destination determination unit 303. Note that in this case, if the signal is transferred to a device different from the next destination device on the route specified by the identification information included in the received signal, the route information changing unit 305 changes the identification information. can be changed. The method of changing this identification information is also as described above, so the description will not be repeated here. The transfer destination change notification unit 306 notifies that the route cannot be used when the signal is transferred to a device different from the next transfer destination device on the route specified by the identification information included in the received signal. A signal for this purpose is transmitted to the base station device 101. Note that the transfer destination change notification unit 306 can notify the device that has determined the route that the route cannot be used. For example, when the base station device 101 determines the route for a signal transmitted from the relay device F107, the forwarding destination change notification unit 306 transmits a notification that the route cannot be used to the base station device 101, and changes the route. If the relay device F107 makes a decision, it can transmit the notification to the relay device F107.

(Processing flow)
The flow of processing executed by the relay device will be outlined using FIG. 4. The process in FIG. 4 is executed, for example, by a relay device that is located in the middle of the path between the base station device and the relay device that is directly connected to the terminal device (that is, a relay device that is not at the end of the path). In this process, the relay device first receives a signal from another device (for example, a base station device or another relay device) (S401). The relay device analyzes the received signal, extracts first identification information indicating the destination device included in the signal and second identification information indicating the route, and based on the second identification information, The route to which the signal should be transferred is specified (S402). Then, the relay device determines a transfer destination device based on the specified route (S403).

For example, if the relay device includes the specified route, the relay device determines the device to which the signal is to be transferred next after the relay device on that route as the transfer destination device. At this time, for example, if a failure occurs in the wireless link between the relay device and the next transfer destination device on the route, the relay device may determine that communication with the next transfer destination device should not be performed. It's possible. In this case, the relay device can determine another device not included in the route as the signal transfer destination. Further, if the relay device does not include the relay device in the specified route, the relay device can independently determine the transfer destination device. The method of determining the transfer destination device in these cases is as described above, so the explanation here will be omitted.

After that, the relay device transfers the signal received in S401 to the destination device determined in S403 (S405). At this time, when the relay device transfers the signal to a device that is not included in the route specified by the second identification information included in the signal, or when the relay device is not included in the route, the relay device transfers the second The identification information can be changed (S404). The process of changing the second identification information is also as described above, so the explanation here will be omitted. Note that the process of S404 does not need to be executed. In addition, when a relay device transfers a signal to a device that is not included in the route specified by the second identification information included in the signal, or when the relay device is not included in the route, the route cannot be used. The base station device 101 may be notified of this (S406). If the relay device identifies that the second identification information has been changed to predetermined information in the received signal, for example, the relay device that changed the information will notify the base station that the route cannot be used. Since it can be assumed that the notification has been sent to the device 101, there is no need to send the notification in S406. Further, if the transfer destination has not been changed, the notification in S406 is not performed. Note that in S406, the device that initially determined the signal transfer route is notified. For example, if the relay device F107 determines the route when transmitting a signal to the base station device 101, a notification is sent to the relay device F107, and the route is determined by the base station device 101. In this case, a notification may be sent to the base station device 101.

In this way, according to the above-mentioned relay device, based on the route identification information included in a signal, in a situation where it is difficult to transfer the signal along that route, it is possible to By continuing the transfer, the signal can be transferred to the destination device. Further, at that time, by appropriately selecting the transfer destination device as described above, efficient signal transfer can be performed. Furthermore, by changing the second identification information indicating the route of the signal to be transferred in accordance with the change of the destination device, it is possible to easily determine the destination of the signal in the destination device. Further, when the transfer destination is changed, by notifying that the initially set route cannot be used, it is possible to prevent signals from being repeatedly transmitted with an unusable route specified.

The present invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the present invention. Therefore, to set out the scope of the invention, the following claims are hereby appended.

Claims (12)

A relay device that relays signals from a base station device or a terminal device to a destination device,
receiving means for receiving the signal;
Destination information indicating a route along which the data included in the received signal is transferred and indicating the destination device included in the received signal when the transfer destination of the signal cannot be specified by the route identification information included in the received signal. determining means for determining a device with which the relay device has established a connection as a device to which the signal is to be transferred based on;
A relay device comprising: If the device to which the signal is transferred can be specified based on the route identification information, the determining means may identify the device with which the relay device has established a connection based on the route identification information. 2. The relay device according to claim 1, wherein the relay device is determined as a transfer destination device. 3. The relay device according to claim 1, wherein the determining means determines the device to which the signal is to be transferred without depending on an instruction from the base station device. 3. The relay device according to claim 1, wherein the determining means determines a device to which the signal is to be transferred in accordance with an instruction from the base station device. In the relay device, a plurality of candidate devices to which the signal is transferred is set,
The determining means determines one of the plurality of signal transfer destination candidate devices as the signal transfer destination device based on the destination information.
The relay device according to any one of claims 1 to 4. 6. The relay device according to claim 5, wherein the relay device establishes a connection with each of a plurality of candidates for transfer destinations of the signal. The route identification information included in the received signal includes information that identifies devices included in the communication path from the base station device or the terminal device to the destination device, and information that indicates the order of devices to which the signal is transferred. The relay device according to any one of claims 1 to 6 , characterized in that it includes the following. further comprising transmitting means for transmitting the signal to the determined transfer destination device,
8. The signal transmitted by the transmitting means includes other route identification information different from the route identification information included in the received signal. relay device. further comprising transmitting means for transmitting the signal to the determined transfer destination device,
8. The relay according to claim 1, wherein the signal transmitted by the transmitting means includes the same route identification information as the route identification information included in the received signal. Device. further comprising transmitting means for transmitting the signal to the determined transfer destination device,
8. The relay device according to claim 1, wherein the signal transmitted by the transmitting means does not include the route identification information. A control method executed by a relay device that relays signals from a base station device or a terminal device to a destination device,
receiving the signal;
Destination information indicating a route along which the data included in the received signal is transferred and indicating the destination device included in the received signal when the transfer destination of the signal cannot be specified by the route identification information included in the received signal. Determining a device with which the relay device has established a connection as a device to which the signal is to be transferred based on;
transmitting the signal to the determined transfer destination device;
A control method characterized by comprising: A computer installed in a relay device that relays signals from a base station device or terminal device to a destination device,
receiving the signal;
Destination information indicating a route along which the data included in the received signal is transferred and indicating the destination device included in the received signal when the transfer destination of the signal cannot be specified by the route identification information included in the received signal. determining the device with which the relay device has established a connection as the device to which the signal is to be transferred based on the
transmitting the signal to the determined transfer destination device;
program.

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