Communication system and transmitting device

Abstract

To reduce the possibility of occurrences of retransmission.SOLUTION: A communication system includes a transmitting device that transmits the same data multiple times and a receiving device that discards data other than the first received data from the same data.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a communication system and a transmission device. [Background technology]

[0002] Communication systems are equipped with a function that retransmits packets when the range of error correction is exceeded. When a retransmission occurs, it appears as if the order of packets has been changed at the receiving end.

[0003] Retransmissions can slow down the data transfer speed. For example, the data window size gradually increases after communication begins, but if an error occurs and a retransmission occurs, the window size returns to a value close to the initial value. Therefore, in order to improve the data transfer speed, it is necessary to change the order of packets and prevent retransmissions. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2020-523897 [Non-patent literature]

[0005] [Non-Patent Document 1] FY2020 L5G Development and Demonstration Results Report_No.8_Realization of wireless in factories (https: / / go5g.go.jp / carrier / l5g / ) Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a communication system and a transmitting device which reduce the possibility of retransmission occurring. [Means for solving the problem]

[0007] One aspect of the present invention is a communication system including a transmitting device that transmits the same data multiple times, and a receiving device that discards data other than the first received data of the same data. Effect of the Invention

[0008] According to the present invention, the possibility of retransmission occurring can be reduced. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram showing a configuration of a communication system according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a diagram showing a sequence diagram of a communication system according to the first embodiment. [Diagram 3] FIG. 11 is a sequence diagram of a communication system according to a second embodiment. [Figure 4] 13 is a flowchart showing the operation of a transmitting device in the third embodiment. [Diagram 5] 13 is a flowchart showing the operation of a receiving device in the third embodiment. [Figure 6] FIG. 13 is a sequence diagram of a communication system according to a fourth embodiment. [Figure 7] FIG. 13 is a sequence diagram of a communication system according to the fifth embodiment. [Figure 8] 13 is a diagram illustrating an example of implementation of a transmitting device and a receiving device in the fourth and fifth embodiments. FIG. [Figure 9] 13 is a diagram illustrating an example of implementation of a transmitting device and a receiving device in the fourth and fifth embodiments. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 is a diagram showing a configuration of a communication system 1 according to this embodiment. The communication system 1 includes a transmitting device 2 and a receiving device 3. The transmitting device 2 transmits data to the receiving device 3.

[0011] Fig. 2 is a diagram showing a sequence diagram of the communication system 1 in the first embodiment. The transmitting device 2 transmits the same data multiple times. In the sequence diagram shown in Fig. 2, the transmitting device 2 transmits data A three times to the receiving device 3. The transmitting device 2 transmits an identification code indicating that the data is A at the same time as the data A.

[0012] The receiving device 3 receives data from the transmitting device 2. The receiving device 3 discards the same data except for the data that was received first. The receiving device 3 judges whether the data is the same or not based on the identification code. This increases the possibility that the data transmitted first (data A in FIG. 2) is received before the data transmitted later (data B in FIG. 2), and reduces the possibility of retransmission.

[0013] The receiving device 3 stores the identification code of the received data and discards data having the same code as the stored identification code. The same identification code may be used repeatedly. In this case, the receiving device 3 discards the stored identification code after a predetermined time has elapsed.

[0014] The process of transmitting multiple times by the transmitting device 2 is realized, for example, by middleware of the transmitting device 2. The middleware of the transmitting device 2, for example, encapsulates data, assigns an identification code, and creates a UDP segment. The process by the transmitting device 2 is not limited to being realized by middleware, and may be realized, for example, by firmware, software, or an application. The discarding of data by the receiving device 3 is achieved by the middleware of the receiving device 3. The middleware of the receiving device 3 discards UDP segments based on, for example, an identification code, decapsulates the remaining UDP segments, and extracts the data.

[0015] 3 is a diagram showing a sequence diagram of the communication system 1 in the second embodiment. In the second embodiment, the transmitting device 2 transmits a sequence number indicating the order of the data together with the data A. The sequence number is a subordinate concept to the identification code in the first embodiment, and indicates that the data is the same and indicates the order of the data.

[0016] In the second embodiment, the receiving device 3 determines whether the data are identical based on the sequence number, and discards the identical data other than the data that was received first. Also, the receiving device 3 in the second embodiment organizes the order of the data based on the sequence number.

[0017] As described above, in the second embodiment, the receiving device 3 rearranges the order of data, thereby preventing the order of data from being reversed due to a difference in the timing of receiving data, and reducing the possibility of retransmission.

[0018] 3, the order of data from the beginning is data A, data B, and data C. In the example shown in Fig. 3, data C is the first data to arrive at the receiving device 3 before data B. At this time, the receiving device 3 swaps the order of data B and data C based on the sequence number, and data B comes before data C. In the receiving device 3, for example, middleware rearranges the order of the data and transfers it to a higher-level configuration.

[0019] In the third embodiment, the communication system 1 uses the identification code according to the first embodiment and the sequence number according to the second embodiment appropriately. When the communication protocol is TCP, a retransmission request occurs if the data order is changed, but when the communication protocol is UDP or ICMP, there is often no problem even if the data order is changed. In the third embodiment, the communication system 1 may perform a process that considers the data order only when the communication protocol is TCP.

[0020] More specifically, the transmitting device 2 and the receiving device 3 perform the following processes. The transmitting device 2 acquires communication protocol information from the data to be transmitted. The transmitting device 2 acquires the upper protocol type by, for example, referring to protocol information in the IP header of the data. If the communication protocol of the data to be transmitted is TCP, the transmitting device 2 assigns a flag to the data to be transmitted indicating that the communication protocol is TCP. This process is performed, for example, when data is encapsulated by middleware to create a UDP segment. Note that if the communication protocol is not TCP, for example UDP or ICMP, the transmitting device 2 may simply send an identification code together with the data.

[0021] The receiving device 3 determines whether the communication protocol is TCP based on a flag included in the data indicating that the communication protocol is TCP. If the communication protocol is TCP, the receiving device 3 arranges the order of the data based on the sequence number. If the communication protocol is not TCP, the receiving device 3 does not need to arrange the order of the data.

[0022] FIG. 4 is a flowchart showing the operation of the transmitting device 2 in the third embodiment. FIG. 4 shows a case where the transmitting device 2 in the third embodiment changes the process depending on the communication protocol. The transmitting device 2 receives a packet as data to be transmitted (step S21). Then, the transmitting device 2 judges whether the protocol information included in the packet is TCP or not (step S22). If the protocol information included in the packet is TCP (step S22: YES), the transmitting device 2 assigns a sequence number and a flag indicating that the packet is TCP to the packet (step S23). If the protocol information included in the packet is not TCP (step S22: NO), the transmitting device 2 assigns an identification number to the packet (step S24). Then, the transmitting device 2 encapsulates the packet including the assigned data, and transmits the packet to the receiving device 3 (step S25).

[0023] FIG. 5 is a flowchart showing the operation of the receiving device 3 in the third embodiment. FIG. 5 shows a case where the receiving device 3 in the second embodiment changes the process depending on the communication protocol. The receiving device 3 receives a packet from the transmitting device 2 (step S31). The receiving device 3 judges whether or not the received packet has a flag indicating that it is TCP (step S32). If the received packet has a flag indicating that it is TCP (step S32: YES), the receiving device 3 performs sequence processing to arrange the order of the packets based on the sequence number (step S33). If the received packet has a flag indicating that it is TCP (step S32: YES), the receiving device 3 performs sequence processing to arrange the order of the packets based on the sequence number (step S33). If the received packet does not have a flag indicating that it is TCP (step S32: NO), the receiving device 3 does not perform the operation of step S33. After that, the receiving device 3 decapsulates the packet and transmits the packet to another device (step S34).

[0024] Furthermore, if the communication protocol is not TCP, for example UDP or ICMP, the transmitting device 2 need only allow the data to pass through without transmitting the data multiple times or performing encapsulation processing. In the third embodiment, the communication system 1 does not perform a process of changing the order of data depending on the type of communication protocol of the data, which makes it possible to reduce the capacity required for data processing.

[0025] 6 is a diagram showing a sequence diagram of the communication system 1 in the fourth embodiment. In the fourth embodiment, when the receiving device 3 receives data indicating a later order first, the receiving device 3 prioritizes reading of already received data over a retransmission notification of unreceived data. In FIG. 6, the transmitting device 2 transmits data to the receiving device 3 in the order indicated by the IDs, simultaneously with IDs 1 to 6 indicating the order of data. The receiving device 3 receives the data of ID 4 transmitted in step S304-1 after the data of ID 1 transmitted in step S301-1. The receiving device 3 reads the data of ID 1 in step S401. Thereafter, the receiving device reads the data of ID 4 in step S402. At the time of completion of step S402, the receiving device has received the data of ID 3 in step S303-1, but has not received the data of ID 2 before the data of ID 4. At this time, the receiving device 3 prioritizes the reading of the already received data of ID 3 over the retransmission notification of the data of ID 2 that has not been received. Therefore, the receiving device 3 reads the data of ID 3 in step S403. This eliminates the need for the receiving device 3 to notify retransmission when the missing data arrives while the data is being read.

[0026] Moreover, the transmitting device 2 in the fourth embodiment transmits information indicating the order of the last transmitted data as a response to the retransmission notification. After reading the data of ID3, the receiving device 3 transmits a retransmission notification of the data of ID2 in step S404. Thereafter, in step S307, the transmitting device 2 transmits the ID of the last transmitted data as information indicating the order of the last transmitted data as a response to the retransmission notification. This allows the receiving device 3 to transmit a retransmission notification of the data if the last data has not arrived.

[0027] Furthermore, the receiving device 3 in the fourth embodiment determines the spectrum efficiency based on the modulation scheme and coding rate (MCS (Modulation and Coding Scheme)), thereby limiting the bandwidth of the data to be received.

[0028] 7 is a diagram showing a sequence diagram of the communication system 1 in the fifth embodiment. In the fifth embodiment, the receiving device 3 estimates unreceived data and generates data.

[0029] 7, in steps S501 to S504, the transmitting device 2 transmits data to the receiving device 3 in the order indicated by the IDs, simultaneously with IDs 1 to 4 indicating the data order. In step S503, the transmitting device 2 fails to transmit the data, and the receiving device 3 does not receive the data of ID 3. The receiving device 3 reads the data of ID1 in step S601, reads the data of ID2 in step S602, and reads the data of ID4 in step S603. In step S604, the receiving device 3 detects that the data of ID3 is missing, and estimates the data of ID3. The receiving device 3 estimates the unreceived data based on, for example, data before and after the ID. The estimation of the unreceived data based on the data before and after the ID is performed, for example, by machine learning the data received in the past and creating a model that complements the data missing from the data pattern.

[0030] In the fifth embodiment, the receiving device 3 can complement the unreceived data by estimating the unreceived data.

[0031] The receiving device 3 in the fifth embodiment may determine whether or not to estimate the missing data based on the received data. When the receiving device 3 determines not to estimate the missing data, it transmits a retransmission notification to the transmitting device 2 in the same manner as in the fourth embodiment. The determination of whether or not to estimate the missing data is made based on the correspondence between the received data and whether or not to estimate the missing data. The correspondence between the received data and whether or not to estimate the missing data is determined, for example, by the type of the received data and whether the type of the data requires urgency, or the ease or accuracy of estimating the missing data from the received data.

[0032] 8 is a diagram showing an example of implementation of the transmitting device 2 and the receiving device 3 in the fourth and fifth embodiments. In the transmitting device 2 and the receiving device 3, UDP is implemented as a lower-level protocol of the General Inter-ORB Protocol (GIOP) of the Common Object Request Broker Architecture (CORBA) standard, and data is transmitted and received using UDP.

[0033] 9 is a diagram showing an example of implementation of the transmitting device 2 and the receiving device 3 in the fourth and fifth embodiments. The transmitting device 2 and the receiving device 3 are provided with a serializer, and the transmitting device 2 converts a structure into a byte sequence using the serializer and transmits the byte sequence from the OutPort to the InPort of the receiving device 3 using a new protocol, and the receiving device 3 converts the byte sequence into a structure using the serializer.

[0034] In addition, the communication system 1 in the fourth and fifth embodiments may perform some of the processing performed by the communication system 1 in the first to third embodiments. For example, the transmitting device 2 may transmit the same data multiple times, or the transmitting device 2 and the receiving device 3 may determine whether the communication protocol is TCP or not and change the processing.

[0035] Other Embodiments Although one embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to the above, and various design changes, etc. are possible within the scope that does not deviate from the gist of the present invention. [Explanation of symbols]

[0036] 1 communication system, 2 transmitting device, 3 receiving device

Claims

1. A transmitting device that transmits the same data multiple times; a receiving device that discards data other than the initially received data among the same data; A communication system comprising:

2. The data includes information indicating a sequence, The receiving device arranges the order of the data based on the order. The communication system according to claim 1 .

3. The data includes information indicating whether the communication protocol is TCP, the receiving device rearranges the order of the data when the data includes information indicating that the communication protocol is TCP, and does not rearrange the order of the data when the data includes information indicating that the communication protocol is not TCP; The communication system according to claim 2 .

4. The receiving device includes: When data indicating a later order is received first, the reading of already received data is prioritized over a resend notification of data that has not been received. The communication system according to claim 1 .

5. the transmitting device transmits information indicating the order of the last transmitted data in response to the retransmission notification.

5. The communication system according to claim 4.

6. Determine the spectral efficiency based on the modulation and coding scheme (MCS); The communication system according to claim 1 .

7. The receiving device includes: When data indicating a later order is received first, data that has not been received is estimated based on data that has already been received. The communication system according to claim 1 .

8. the receiving device, when receiving data indicating a later order first, determines whether or not to estimate data that has not been received based on data that has already been received; If it is determined that the unreceived data should not be estimated, a retransmission notification of the unreceived data is transmitted to the transmitting device.

8. The communication system according to claim 7.

9. Duplicate the data to be sent and send multiple pieces of data. Transmitting device.

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