JP6824027B2 - Communication equipment, its control method, and programs - Google Patents

Description

Regarding communication devices, their control methods, and programs.

In recent years, network communication by Ethernet has been generally used, and the range of application has expanded from the Internet to local area networks and inter-device communication. For example, in addition to conventional file sharing and forwarding, file data transmission using applications such as mail and HTTP (Hypertext Transfer Protocol), stream data communication such as Audio / Video represented by VOD (Video On Demand). The application to is increasing. Furthermore, Ethernet AVB, which is a protocol standard that uses Ethernet to transmit stream data such as Audio / Video (hereinafter referred to as AV data) in real time and enables synchronous playback with other communication nodes, is available for professional audio and in-vehicle equipment. , Industrial and broadcasting systems are beginning to attract attention.

Ethernet AVB defines a function for synchronizing time between nodes and a QoS (Quality of Service) function for transmitting data within a predetermined delay amount as functions provided by each communication node. Further, in Ethernet AVB, a group of a plurality of communication nodes capable of communicating with a predetermined delay and being able to synchronize time with each other is called an AVB domain. In the AVB domain, a delay of up to 7 hops and 2 ms is guaranteed between nodes connected at a communication link speed of 100 Mbit Ethernet (hereinafter, 100 MbE) or higher.

In Ethernet AVB, in order to ensure real-time performance, a transmitting node (hereinafter, transmitting node) among communication nodes transmits a message to a receiving node (hereinafter, receiving node) whose delay amount can be grasped. Further, the relay node that transfers (relays) the message transmitted from the transmitting node to the receiving node adds, updates, and transmits the cumulative delay amount in the message when transferring the message. Therefore, the receiving node can grasp the cumulative delay amount from the received message and determine whether or not real-time communication is possible. The amount of delay between each communication node is calculated based on the device internal delay, transfer frame size, communication link speed, and available bandwidth.

Patent Document 1 proposes a method for determining whether or not real-time communication is possible during packet relay. Specifically, the relay node compares the scheduled transmission time calculated from the information contained in the received packet with the transmission startable time held by the relay node, and determines whether or not the relay is possible. Then, when the relay node determines that the relay is not possible, the relay node discards the received packet. As a result, unnecessary forwarding of packets on the network is avoided, and real-time communication can be efficiently performed.

Japanese Unexamined Patent Publication No. 2009-260888

Even in a system intended for real-time communication, if the default number of hops from the transmitting node is exceeded, the processing performance is low, or the processing load is high on the receiving node, the default delay amount may not be satisfied and real-time communication may break down. .. When the real-time communication is broken, the receiving node deteriorates the reproduction quality in the stream reproduction of AV data and the like. In addition, since the set data reproduction time is not met, there is a problem that synchronization with other receiving nodes occurs during reproduction.

The present invention has been made in view of the above problems, and an object of the present invention is to realize real-time communication satisfying a specified delay amount in a network having a plurality of communication devices.

As one means for achieving the above object, the communication device of the present invention has the following configuration. That is, a communication device that receives data from a transmission device in a network, and a determination means for determining whether or not the data transmitted from the transmission device can be received within a predetermined time, and the determination means. When it is determined that the data cannot be received from the transmitting device within a predetermined time, a device satisfying a predetermined condition is selected as the transfer device among a plurality of other communication devices in the network. A selection means, a transmission means for transmitting transfer information including information for identifying the transfer device to the transmission device and the transfer device, and a receiving means for receiving the data from the transmission device via the transfer device. When having a predetermined condition is a condition for the time from the transmitter to the transfer the communication device via the device receives the data to be within the predetermined time period is there.

According to the present invention, real-time communication satisfying a predetermined delay amount is realized in a network having a plurality of communication devices.

The schematic block diagram of the communication system in an embodiment. The figure which shows the example of data transmission in Embodiment 1. FIG. The figure which shows the node list example. Schematic internal block diagram of the transmitting node in the embodiment. Schematic internal block diagram of the receiving node in the embodiment. The processing flowchart of the transmission node in Embodiment 1. The processing flowchart of the receiving node in Embodiment 1. A sequence chart showing the operation of each node in the communication system according to the first embodiment. The processing flowchart of the transmission node according to Embodiment 2.

Hereinafter, the present invention will be described in detail based on the embodiments with reference to the accompanying drawings. The configuration shown in the following embodiments is only an example, and the present invention is not limited to the illustrated configuration.

[Embodiment 1]
FIG. 1 shows a schematic configuration diagram of the communication system 10 according to the embodiment of the present invention. The communication system 10 shown in FIG. 1 has a configuration assuming a real-time communication system in a broadcasting system site. The communication system 10 is composed of eight communication nodes (communication devices) 101 to 108, four relay nodes 111 to 114, and a content source 110. An example of the communication node 101 is a video camera having an imaging function. Examples of communication nodes 102 to 108 are a projector for viewing a video, a liquid crystal display for checking a video, editing equipment for editing a video, a PC for performing video processing calculations such as analysis and composition of a video, and the like.

The video data captured by the communication node 101 is temporarily buffered in the content source 110. After that, the communication node 101 takes out the video data from the content source 110 and delivers it to the communication nodes 102 to 108 while satisfying the predetermined delay amount (delay time). Each of the communication nodes 102 to 108 executes various applications such as video output, editing, analysis, and video composition in real time according to each device. Further, for example, the communication node 102 and the communication node 103 may be configured to form a multi-projection and output video in synchronization with each other.

In the network, the communication nodes 101 to 108 are connected to each other via the relay nodes 111 to 114, which are network hubs that support real-time communication. Here, it is assumed that each of the communication nodes 101 to 108 and the relay nodes 111 to 114 corresponds to a protocol standard capable of real-time synchronous communication such as Ethernet AVB. Further, the communication nodes 101 to 108 are provided with communication interfaces corresponding to different communication speeds. For example, as shown in FIG. 1, communication nodes 103, 105, and 107 have a 1 GbE communication interface, and communication nodes 102, 104, 106, and 108 have a 100 MbE communication interface. Further, the communication node 101 and the relay nodes 111 to 114 shall be provided with a communication interface of 1 GbE or more.

In the communication system 10 as shown in FIG. 1, before the start of real-time communication, the communication nodes 102 to 108 determine whether or not the AV data from the communication node 101, which is a transmission node, can be received within a predetermined delay amount. It is necessary to judge. As an example of the delay condition in the communication system 10, the delay amount is defined as 2 ms or less, and the operation of determining whether or not the delay condition is satisfied in the communication nodes 102 to 108 will be described below.

The communication node 101 transmits a message including the required bandwidth of the AV data to be transmitted to the communication nodes 102 to 108. At that time, each relay node 111 to 114 adds (updates) the delay amount generated in each hop to the same message as the cumulative delay amount and transfers it. The transferred message may include an AV stream ID and a VLAN (Virtual Local Area Network) ID specified by Ethernet AVB in addition to the required bandwidth and cumulative delay amount. The communication nodes 102 to 108 determine whether or not real-time communication is possible based on the cumulative delay amount of the received message, the required bandwidth, and the like, and notify the communication node 101 of the determination result.

In the example of FIG. 1, it is assumed that the communication node 101 transmits AV data with a bandwidth of 75 Mbps. Further, the amount of delay generated in each hop is calculated based on information such as the required bandwidth, and in this example, it is assumed to be 0.5 ms per hop. Under such conditions, it takes 5 hops from the communication node 101 to the communication node 108, so that the communication node 108 has a cumulative delay amount of 2.5 ms. As described above, since the delay amount specified for real-time communication is 2 ms or less, the cumulative delay amount (2.5 ms) at the communication node 108 cannot satisfy the specified delay amount. In this case, the communication node 108 notifies the communication node 101 that the delay amount cannot be satisfied.

Hereinafter, when a communication node (hereinafter, delay node) that does not satisfy the predetermined delay amount such as the communication node 108 in FIG. 1 occurs, the method of relieving the delay node so as to satisfy the specified delay amount will be described. To do. In the present embodiment, in order to relieve the delayed node, a communication node (hereinafter referred to as a transfer node) that transfers data to the delayed node so that the delay condition can be achieved is provided.

Here, the configurations of the communication node 101, which is a transmission node, and the communication nodes 102 to 108, which are reception nodes, will be described with reference to FIGS. 4 and 5.

FIG. 4 shows an internal block diagram of the communication node 101, which is a transmitting node. Processor 405 controls each functional block. The memory 404 is a memory space shared and used by each block. The processor 405 is composed of a CPU or MPC, and controls the entire communication node 101 by executing a program stored in the memory 404. For example, the flowcharts of FIGS. 6 and 9 described later are realized by the processor 405 executing the program stored in the memory 404. The address data bus 403 is used to exchange data between functional blocks. The communication unit 400 is used for data communication between other communication nodes 102 to 108 and relay nodes 111 to 114 and the content source 110. The communication unit 400 may be configured to include a communication interface independent of communication with other communication nodes 102 to 108 and relay nodes 111 to 114 for data communication with the content source 110.

The AV data (video data) acquired by the imaging unit 407 is subjected to processing such as compression as necessary in the AV data processing unit 408, and is temporarily stored in the content source 110 via the communication unit 400. The AV data stored in the content source 110 is read from the communication unit 400 at a predetermined read speed, and is output to the other communication nodes 102 to 108 and the relay nodes 111 to 114. However, if the waiting time until data transmission is short and the AV data can be buffered in the memory 404, it does not necessarily have to be temporarily stored in the content source 110.

Here, the read speed by the communication unit 400 is determined by the compression rate of AV data in the AV data processing unit 408, the bandwidth that the communication node 101 can use for real-time communication, the delay condition in the communication system 10, the presence or absence of the transfer node, and the like. Can be done.

The transfer node candidate selection unit 401 creates a node list 300 as described with reference to FIG. 3, and transmits the node list 300 to the communication node 108, which is a delay node, via the communication unit 400.

Here, the node list created by the transfer node candidate selection unit 401 will be described. Generally, as the forwarding node, the communication node having a high communication link speed between the transmitting node and the delay node and having the shortest number of hops (shortest distance) is suitable. Therefore, the transfer node candidate selection unit 401 first, as a transfer node candidate, has a communication link speed (100 MbE in the example of FIG. 1) or more secured between the communication node 101 and the communication node 108. Select a communication node that can communicate with. The transfer node candidate selection unit 401 refers to the communication link speed to each communication node 102 to 108, for example, that is stored in the memory 404 when the communication link with each communication node 102 to 108 is established. The transfer node candidate selection unit 401 creates a node list 300 as shown in FIG. 3 from the selected communication nodes (transfer node candidates). As shown in FIG. 3, in the configuration of FIG. 1, the candidates for the transfer node are communication nodes 103, 105, and 107 having a communication link speed of 100 MbE or more with the communication node 101.

The node list 300 created by the transfer node candidate selection unit 401 is transmitted by the communication unit 400 to the communication node 108, which is a delay node. The communication node 108 determines as the transfer node the node having the smallest number of hops with the communication node 108 in the node list 300 received from the communication node 101. In the configuration of FIG. 1, since the number of hops between the communication node 108 and the communication nodes 103, 105, and 107 is 5, 3, and 2 hops, respectively, the communication node 107 having the smallest number of hops is selected as the transfer node. .. Here, when a plurality of communication nodes having the same number of hops are selected, a communication node having a communication link speed with the transmitting node as high as possible may be selected as the transfer node.

Next, the configurations of the communication nodes 102 to 108, which are the receiving nodes, will be described. FIG. 5 shows an internal block diagram of communication nodes 102 to 108, which are receiving nodes. The processor 505 controls each functional block in the same manner as the transmission node configuration shown in FIG. The memory 504 is a memory space shared and used by each block. The processor 505 is composed of a CPU or MPC, and controls the entire communication node 101 by executing a program stored in the memory 504. For example, the flowchart of FIG. 7, which will be described later, is realized by the processor 505 executing the program stored in the memory 504. The address data bus 503 is used for exchanging data between each functional block.

The communication nodes 102 to 108 include a communication unit 500 for data communication with other communication nodes 101 to 108 and relay nodes 111 to 114. The AV data from the communication node 101 received by the communication unit 500 is temporarily stored in the memory 504. The AV processing unit 508 reads the AV data stored in the memory and converts it into data that can be displayed by the video output unit 507. In the present embodiment, the configuration of the receiving node is a configuration in which a liquid crystal projector or a display is used as an example, but the configuration is not limited to this and may be editing equipment. In the case of editing equipment, the video output unit 507 may be a monitor output and a user interface such as a switch or a volume.

When the own station is a delay node, the transfer node determination unit 501 determines (selects) the transfer node from the node list 300 received from the transmission node. Subsequently, the transfer node determination unit 501 creates transfer information. The transfer node determination unit 501 includes the determined transfer node identification information in the transfer information. The identification information is information that can be identified by the transfer node, such as an IP address. Further, the transfer information may include identification information of the delay node such as the IP address of the delay node. Further, the transfer node determination unit 501 derives the communication speed between the transmission node and the transfer node and the communication speed between the transfer node and the delay node, and includes them in the identification information. These communication speeds are calculated based on, for example, the number of hops, the amount of delay, the communication link speed, and the like between the transmission node and the transfer node, and between the transfer node and the delay node.

Here, when calculating each communication speed, the bandwidth occupancy rate and the like that can be secured in each route may be included. Further, although the number of hops or the delay amount between each communication node is grasped in advance by the receiving node, the above-mentioned cumulative delay amount acquisition method between each communication node is described after the transfer information is transmitted. It may be measured in the same manner as above.

It is assumed that the configuration of the transfer node (communication node 107 in the example of FIG. 1) is the same as that of the receive node in FIG. However, the communication unit 500 shall be able to transfer the AV data transmitted from the transmitting node to the delay node.

Subsequently, FIG. 2 shows an example of data transmission in this embodiment. In FIG. 2, the delay node is the communication node 108, and the transfer node is the communication node 107. Here, it is assumed that the communication node 107 can form a communication link of 1 GbE with the communication node 101 that transmits data, and the communication node 101 and the communication node 108 form a communication link of 100 MbE.

In order to achieve the delay condition of the communication node 108, the communication node 101 transmits AV data to the communication node 107 at 375 Mbps, which is five times the communication speed of the transmission example shown in FIG. Since AV data can be transmitted at a high rate (375 Mbps) from the communication node 101 to the communication node 107, the delay amount per hop is 0.15 ms. Therefore, the cumulative delay amount from the communication node 101 to the communication node 107 is 0.75 ms. For the sake of simplification of calculation, it is assumed that the delay amount generated in the internal processing in each relay node 111 to 114 is the same, but each relay node 111 to 114 has a different delay amount. You may be doing it.

The communication node 107 buffers the received AV data for an application to be executed by its own station, and at the same time transfers it to the communication node 108. At this time, since the communication node 107 and the communication node 108 have a communication link speed of 100 MbE, communication is performed at a low rate (75 Mbps). Therefore, between the communication node 107 and the communication node 108, the delay amount per hop is 0.5 ms, which is the same as in the case of the transmission example in FIG. Therefore, the cumulative delay amount from the communication node 101 to the communication node 108 is 1.75 ms including the transfer path, and the communication node 108 can achieve the delay condition of the specified delay amount of 2 ms or less.

FIG. 6 shows a processing flowchart of the transmission node (communication node 101 in FIG. 2) in the present embodiment. In the S600, the transmitting node determines whether or not the delay node exists based on whether or not the receiving node (communication nodes 102 to 108 in FIG. 2) has received a notification indicating that the delay amount is not satisfied. For example, if it is determined that the delay node does not exist by not receiving the notification within a certain period of time (No in S600), the transmitting node transmits the AV data to each receiving node or to the broadcast, and this The flow chart ends. On the other hand, if it is determined that a delay node exists (Yes in S600), the delay node is identified, and in S601, the transmission node communicates with the transmission node at a speed higher than the communication link speed with the delay node. Select possible nodes (ie, transfer node candidates) and create a node list 300. In S602, the transmitting node transmits the node list 300 to the deferred node.

In S603, the transmitting node receives the identification information of the selected transfer node, the communication speed between the transmitting node and the transfer node, and the transfer information including the communication speed between the transfer node and the delay node from the delay node. In this flowchart, the delay node derives the communication speed between the transmission node and the transfer node and the communication speed between the transfer node and the delay node, and includes each communication speed in the transfer information. However, this is not the case, and the transmitting node may calculate each communication speed. When the transmitting node calculates each communication speed, information on the number of hops or the amount of delay between the delay node and the transfer node and between the transmission node and the transfer node may be received from the delay node. Furthermore, even if the forwarding node specifies (adds) the number of hops or the delay amount when the information on the number of hops or the delay amount between the transmitting node and the forwarding node is transmitted to the transmitting node via the forwarding node. Good.

In addition, the transfer information transmitted from the delay node to the transmission node in S603 can also be received by other receiving nodes, and a specific receiving node grasps from the transfer information that its own station has been selected as the transfer node. To do. At this time, if the transfer information includes the identification information of the delay node, the transfer node can grasp the transfer destination of the AV data. Further, the transfer node may grasp the transfer destination of the AV data by transmitting the information about the delay node from the transmission node.

In S604, the transmitting node transmits data to the transfer node at a high rate according to the transfer information. Here, the high rate is assumed to be a communication speed higher than the communication link speed between the transmitting node and the delay node.

FIG. 7 shows a processing flowchart of the receiving nodes (communication nodes 102 to 108 in FIG. 2) in the present embodiment. In the S700, the receiving node receives a message from the transmitting node (communication node 101 in FIG. 2) including the cumulative delay amount by each relay node (relay nodes 111 to 114 in FIG. 2) and the required bandwidth of AV data. Then, it is determined whether or not the own station satisfies the specified delay amount (whether or not it is equal to or more than the threshold value). If it is determined that the predetermined delay amount is satisfied (not above the threshold value) (No in S700), the receiving node receives the AV data from the transmitting node and reproduces it in real time through a predetermined process. This flowchart ends. On the other hand, if it is determined that the predetermined delay amount is not satisfied (greater than or equal to the threshold value) (Yes in S700), the receiving node notifies the transmitting node that the own station is a delay node in S701.

In S702, the receiving node receives the node list 300 from the transmitting node. In S703, the receiving node selects the communication node having the smallest number of hops with its own station or the minimum amount of delay from the node list 300 as a transfer node, and creates transfer information by the method described above. In S704, the receiving node transmits the transfer information to the transfer node and the transmission node. In S705, the receiving node receives the AV data from the transmitting node from the forwarding node. Here, it is assumed that the transmission speed at the time of transfer follows the transfer information. AV data is transferred from the transfer node to the delay node at a low rate, but the AV data is transmitted from the transmission node to the transfer node at a high rate, and as a result, the delay node satisfies the predetermined delay amount. It becomes possible.

FIG. 8 shows a sequence chart showing the operation of each node in the communication system 10 according to the present embodiment. In the S800, the communication node 101 transmits a message including the required bandwidth and cumulative delay amount of the AV data to be transmitted to each communication node. In S801, each relay node 111 to 114 adds and updates the delay amount to the delay amount field in the message. In S802 to S804, communication nodes 102 to 108 receive a message including the cumulative delay amount. In S805, the communication node 108 determines from the cumulative delay amount of the message that the predetermined delay amount cannot be satisfied by the own station, and notifies the communication node 101 that the specified delay amount (delay condition) cannot be satisfied.

In S806, the communication node 101 recognizes that the communication node 108 is a delay node. In S807, the communication node 101 selects a candidate transfer node that can rescue the delay node and creates a node list 300. In S808, the communication node 101 transmits the created node list 300 to the communication node 108, which is a delay node, and the communication node 108 receives this in S809.

In the S810, the communication node 108 determines the communication node 107 having the smallest number of hops and its own station as a transfer node from the node list 300. Further, the communication node 108 derives the communication speed at the time of data transfer between the communication node 101 and the communication node 107, and between the communication node 107 and the communication node 108, and includes the communication speed in the transfer information. The transfer information also includes the identification information of the communication node 107 (and the identification information of the communication node 108). In S811, the communication node 108 transmits the transfer information to the communication node 107 and the communication node 101. In S812, the communication node 107 that has received the transfer information recognizes that its own station is the transfer node of the communication node 108.

In S813, the communication node 101 grasps that the communication node 107 has been selected as the transfer node from the transfer information received from the communication node 108. In S814, the communication node 101 transmits AV data to the communication node 107 at a high rate according to the transfer information. The communication rate at this time is determined so that a predetermined delay amount is achieved with respect to the number of hops between the transmission node and the transfer node, the number of hops between the transfer node and the reception node, or the delay amount.

In the S815, the communication node 107 buffers the received AV data for an application to be executed by its own station, and at the same time, transmits data to the communication node 108, which is a delay node, at a low rate. Here, the low rate means that the communication speed is lower than the communication between the communication node 101 and the communication node 107. Further, the low rate in the present embodiment is assumed to be a communication speed that can be received at a communication link speed of 100 MbE.

In the S816, the received AV data is buffered in the memory 504 until the communication node 108 receives the AV data within the specified delay amount and performs synchronous playback of the received data. In S817, the communication node 101 retransmits the same AV data to the communication nodes 102 to 106 at a low rate. Here, when transferring AV data from the communication node 107 to the communication node 108 at a low rate, the communication nodes 102 to 106 may also receive the AV data, but some communication nodes do not satisfy the predetermined delay amount. there is a possibility. Therefore, here, the communication node 101 retransmits the AV data at a low rate. Further, in this sequence chart, high-rate transmission and low-rate transmission of AV data are performed in chronological order, but they may be transmitted at the same time if there is a margin in the communication band.

In S819, execution of various applications such as data reproduction is started in synchronization with each communication node 102 to 108. Here, since there was a projector that performs multi-projection in the communication system, a sequence chart in which all receiving nodes perform synchronous playback was described. However, this is not limited to this, and other applications such as video analysis and video processing operations such as compositing may be started immediately after receiving the AV data.

[Embodiment 2]
In the first embodiment, in S601 of FIG. 6, the transmitting node simply selects a communication node whose communication link speed with the transmitting node is equal to or higher than the communication link speed with the delayed node as a transfer node candidate, and creates a node list 300. In the second embodiment, a method will be described in which the transmitting node selects a communication node with better conditions as a transfer node candidate. Hereinafter, a part different from the first embodiment will be described.

FIG. 9 shows a processing flowchart of the transmitting node in the second embodiment. In the S600, the transmitting node determines the presence or absence of the delayed node. In S601, the transmitting node selects a node capable of communicating with the transmitting node at a speed higher than the communication link speed with the delay node. In the S900, the transmitting node selects a communication node whose occupancy ratio of the communication band allocated to communication with the transmitting node is equal to or greater than the threshold value from the nodes selected in S601.

In S901, the transmitting node selects a communication node belonging to a high priority group from the communication nodes selected in S900. As a premise for this, each communication node shall belong to one of a plurality of priority groups. For example, in Ethernet AVB, the AVB domain is formed for each delay condition and priority of the stream (data) to be transmitted. Therefore, each communication node belongs to a different AVB domain if the stream priority is different. Here, the priority group is the same as the above AVB domain in Ethernet AVB.

Needless to say, any one of the processes of S601, S900, and S901 may be adopted, or the processing order may be changed. Since the following processing flow is the same as that in FIG. 6, the description thereof will be omitted.

As described above, according to the embodiment described above, in a communication system in which a plurality of communication nodes having different communication link speeds transmit data within a predetermined delay amount, the communication nodes that do not satisfy the delay amount are relieved. Is possible. Specifically, when the transmitting node detects a delayed node that cannot receive the communication packet with the predetermined delay amount, the forwarding node that can rescue the delayed node forwards the communication packet received at high speed from the transmitting node to the delayed node. The default amount of delay can be achieved with.

That is, it is possible to make the receiving node that does not satisfy the predetermined delay amount communicate in real time by providing the forwarding node that can receive the packet from the transmitting node at high speed. In addition, in a real-time communication system including 100MbE, which is slower than 1GbE (Gigabit Ethernet) or 2.5GbE, it is possible to perform communication with a further reduced delay by providing a transfer node that assists the low-speed communication node. It will be possible. Since the amount of delay is reduced, it is possible to prevent synchronization deviation with other receiving nodes during playback.

The above communication system has been described assuming a broadcasting site where real-time communication is indispensable, but it is not limited to this, and it is not limited to this, and multi-projection, home theater system, industrial system, and in-vehicle system composed of other types of devices are used. It may be an application of.

Further, in the flowcharts of FIGS. 6, 7 and 9 described above, the processors of the transmitting node or the receiving node execute the control program stored in the memory, calculate and process the information, and control each hardware. It was explained as being realized. However, a configuration may be configured in which some or all of the steps shown in these flowcharts are realized by hardware such as an ASIC.

<Other Embodiments>
The present invention supplies a program that realizes one or more functions of the above-described embodiment to a system or device via a network or storage medium, and one or more processors in the computer of the system or device reads and executes the program. It can also be realized by the processing to be performed. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

101-108 communication node, 111-114 relay node, 110 content source, 300 node list, 401 transfer node candidate selection unit, 501 transfer node determination unit

Claims (13)

A communication device that receives data from a transmitter in a network.
A determination means for determining whether or not the data transmitted from the transmission device can be received within a predetermined time, and
When the determination means determines that the data cannot be received from the transmission device within a predetermined time, the transfer device transfers a device that satisfies a predetermined condition among a plurality of other communication devices in the network. And the selection method to select as
A transmission means for transmitting transfer information including information for identifying the transfer device to the transmission device and the transfer device, and
A receiving means for receiving the data from the transmitting device via the transfer device, and
Have,
The predetermined condition is a condition for ensuring that the time from the transmitting device to the communication device receiving the data via the transfer device is within the predetermined time. Communication device. When the determination means determines that the data transmitted from the transmission device cannot be received within the predetermined time, the transmission device indicates that the data cannot be received within the predetermined time. Has more notification means to notify
The selection means selects the transfer device from a list of the other communication devices that satisfy the first condition regarding the communication speed among the predetermined conditions received from the transmission device in response to the notification by the notification means. The communication device according to claim 1, wherein the communication device is selected. The selection means uses a communication device that satisfies the second condition regarding the distance from the communication device among the predetermined conditions from the other communication device that satisfies the first condition in the list as the transfer device. The communication device according to claim 2, wherein the communication device is selected. The first condition is that the communication speed in communication with the transmission device is faster than the communication speed secured between the transmission device and the communication device, and the second condition is from the communication device. The communication device according to claim 3, wherein the distance is the shortest among the devices that are candidates for the transfer device. The transfer information includes information for identifying the transfer device, a communication speed in communication between the transmission device and the transfer device, and a communication speed in communication between the transfer device and the communication device. The communication device according to any one of claims 1 to 4, wherein the communication device is characterized by the above. A communication device that sends data to other communication devices in the network.
Among other communication devices in the network, a specific means for identifying a communication device that cannot receive data transmitted from the communication device within a predetermined time, and
Among the other communication devices, a notification means for notifying the specified communication device of information on a communication device capable of communicating at a speed higher than a predetermined communication speed, and
Wherein the specified communication device, wherein a communication device selected based on the information notified by the notification unit, wherein the communication device receiving the said data the specified communication device via the transfer device from A receiving means for receiving transfer information including information of the transfer device selected so that the time required for the transfer is within the predetermined time.
A transmission means for transmitting the data to the transfer device based on the transfer information, and
A communication device characterized by having. The communication device according to claim 6, wherein the predetermined communication speed is a communication speed secured between the communication device and the specified communication device. 6. The transfer information is characterized in that the communication speed between the communication device and the transfer device and the communication speed between the transfer device and the specified communication device are included in claim 6. The communication device described. The information notified by the notification means is that of a communication device capable of communicating at a speed higher than the predetermined communication speed, in which the occupancy ratio of the communication band allocated for communication with the communication device is equal to or higher than a predetermined threshold value. The communication device according to any one of claims 6 to 8, wherein the communication device includes information. Any one of claims 6 to 9, wherein the information notified by the notification means includes a communication device having a high priority among communication devices capable of communicating at a speed higher than the predetermined communication speed. The communication device described in the section. A control method for a communication device that receives data from a transmitter in a network.
A determination step of determining whether or not the data transmitted from the transmission device can be received within a predetermined time, and a determination step.
When it is determined in the determination step that the data cannot be received from the transmission device within a predetermined time, a transfer device that satisfies a predetermined condition among a plurality of other communication devices in the network. The selection process to select as
A transmission step of transmitting transfer information including information for identifying the transfer device to the transmission device and the transfer device, and
A receiving step of receiving the data from the transmitting device via the transfer device, and
Have,
The predetermined condition is a condition for ensuring that the time from the transmitting device to the communication device receiving the data via the transfer device is within the predetermined time. Control method. A control method for a communication device that sends data to other communication devices in the network.
A specific step of identifying a communication device that cannot receive data transmitted from the communication device within a predetermined time among other communication devices in the network.
A notification step of notifying the specified communication device of information on a communication device capable of communicating at a speed higher than a predetermined communication speed among the other communication devices.
A transfer device that is a communication device selected based on the information notified in the notification process by the specified communication device, wherein the specified communication device is transmitted from the communication device via the transfer device. A receiving step of receiving transfer information including information of the transfer device selected so that the time until receiving the data is within the predetermined time, and
A transmission step of transmitting the data to the transfer device based on the transfer information,
A control method characterized by having. A program for causing a computer to function as the communication device according to any one of claims 1 to 10.

Images