JP6973511B2 - Communication equipment, communication systems, communication methods and programs - Google Patents

Description

The present invention is based on the priority claim of Japanese patent application: Japanese Patent Application No. 2018-01571 (filed on January 25, 2018), and all the contents of the application are incorporated in this document by citation. It shall be.
The present invention relates to communication devices, communication systems, communication methods and programs.

In recent years, with the spread of smartphones and the like, traffic on mobile networks has been increasing. One of the technologies for dealing with the increase in traffic is Carrier Aggregation (CA) introduced from LTE (Long Term Evolution) -Advanced. CA is a technology that realizes high-speed mobile communication as compared with the case of a single CC by using a plurality of frequency lines called component carriers (CC) at the same time.

However, in communication to which CA technology is applied, the communication performance may not be maximized. This is because the communication device on the Internet side, which controls the transport layer independently of the data link layer of the base station, cannot grasp the status of the base station.

For example, TCP (Transmission Control Protocol) is known as a transport layer communication protocol used as standard on the Internet and the like. In a general transport layer protocol represented by TCP, it is not possible to grasp the communication status of the base station such as whether or not the base station and the terminal are retransmitted. Therefore, inconsistency may occur between the communication control of the base station and the communication control of the upper layer of the Internet, and a predetermined communication performance may not be achieved.

For example, when the base station transmits data to the terminal, the data to be transmitted is stored in the transmission buffer of the base station. Here, the transmission buffer of the base station is a storage area of the base station itself. When the transmission buffer of the base station is temporarily empty, the base station has no choice but to stop the transmission. However, it is not possible to grasp the situation where the transmission buffer of the base station is temporarily empty. Therefore, the communication device on the Internet side cannot complete the data transmission to the base station. As a result, the wireless resources transmitted from the communication device on the Internet side are wasted. Therefore, if the transmission buffer of the base station becomes empty during data transmission from the communication device on the Internet side, the time required for data transmission becomes large, and the throughput, which is the end-to-end communication speed, becomes small.

To deal with such problems, there is a technique for controlling the transport layer that improves the end-to-end throughput.

For example, in Patent Document 1, the bandwidth of the path between the communication device on the transmitting side and the communication device on the receiving side is wide, the path is long, and the RTT (Round Trip Time) is large (referred to as high delay). ), Technologies such as communication devices that can improve throughput are disclosed. Specifically, the communication device of Patent Document 1 transitions from the first state to the second state when it is determined that the environment is a wide band and a high delay environment. Here, the first state is a state in which the transmission window size is a window size (first window size) that does not exceed the reception window size. The second state is a state in which the transmission window size exceeds the reception window size (second window size). Next, when the communication device of Patent Document 1 transitions to the second state, it transmits a packet having a size exceeding the reception window size. As a result, the transmitting device of Patent Document 1 can improve the end-to-end throughput by transmitting data exceeding the maximum amount of data that can be transmitted notified from the receiving side.

Japanese Unexamined Patent Publication No. 2012-095190 International Publication No. 2016/0239335

The disclosures of the above prior art documents shall be incorporated into this document by citation. The following analysis was made by the present inventors.

In the technique disclosed in the above-mentioned patent document, data is additionally transmitted when it is determined that the environment is wide band and high delay. This prevents the transmission buffer from becoming empty in the device on the communication path. However, this technique cannot solve the problem that the transmission buffer of the base station becomes empty. This is because the technology may not be able to additionally transmit data at an appropriate timing. Hereinafter, the above problems will be described in detail.

In general communication standards, it is inevitable that an error will occur during the communication process. Therefore, a general communication standard defines a transmission error detection method and a retransmission control method.

For example, a general communication standard defines a method for detecting an error when transmission fails in the lower layer. Further, in a general communication standard, when a retransmission occurs, a method of controlling the retransmission is defined so that the communication of the upper layer is not completed until the retransmission is successful. Further, in a general communication standard, when a retransmission occurs in a lower layer, a method is also specified in which subsequent packets wait until the retransmission is completed to control the retransmission.

Hereinafter, a case where the terminal device on the transmitting side transmits data to the terminal device on the receiving side via the base station using the TCP protocol will be described as an example with reference to FIG.

FIG. 2 is a block diagram showing an example of the protocol configuration of the base station 103 and an example of the protocol configuration of the terminal device.

Base station 103 is a 3GPP Rel. It has a general configuration of 10 or later. Specifically, the base station 103 includes a base station PDCP (Packet Data Convergence Protocol) layer 1031, a base station RLC (Radio Link Control) layer 1032, one or more MAC (Media Access Control) layers, and one. Alternatively, it comprises two or more physical layers. The base station PDCP layer 1031 is a PDCP layer of the base station 103. The base station RLC layer 1032 is the RLC layer of the base station 103.

In addition, in FIG. 2, in order to clarify the relationship between the base station 103 and the terminal device, the description regarding the configuration of the base station 103 other than the U-Plane protocol is omitted. In FIG. 2, two MAC layers of the base station 103 (base station MAC layers 1033a and 1033b) are shown, but this does not mean that the number of MAC layers of the base station 103 is limited to two. Similarly, in FIG. 2, two physical layers of the base station 103 (base station physical layers 1034a and 1034b) are shown, but this is not intended to limit the number of physical layers of the base station 103 to two. In the following description, the MAC layer of the base station 103 will be referred to as the base station MAC layer 1033 when it is not necessary to distinguish them from each other. Similarly, in the following description, the physical layer of the base station 103 is referred to as the base station physical layer 1034 when it is not necessary to distinguish them from each other.

Similarly, the terminal device communication unit 121, which is a communication means of the terminal device, has 3GPP Rel. It has a general configuration of 10 or later. The terminal device communication unit 121 includes a terminal transport layer 1210, a terminal PDCP layer 1211, a terminal RLC layer 1212, one or more MAC layers, and one or more physical layers. The terminal transport layer 1210 is a transport layer of the terminal device. The terminal PDCP layer 1211 is a PDCP layer of the terminal device. The terminal RLC layer 1212 is an RLC layer of the terminal device.

In FIG. 2, two MAC layers (terminal MAC layers 1213a and 1213b) of the terminal device are shown, but this does not mean that the number of MAC layers of the terminal device is limited to two. Similarly, in FIG. 2, two physical layers of the terminal device (terminal physical layers 1214a and 1214b) are shown, but this is not intended to limit the number of physical layers of the terminal device to two. In the following description, the MAC layer of the terminal device will be referred to as the terminal MAC layer 1213 when it is not necessary to distinguish them from each other. Similarly, in the following description, the physical layer of the terminal device is referred to as the terminal physical layer 1214 when it is not necessary to distinguish them from each other.

In the standard model of 3GPP (Third Generation Partnership Project), the base station RLC layer 1032 is connected to at least one base station MAC layer 1033. Further, the RLC layer (terminal RLC layer 1212) of the terminal device is connected to at least one MAC layer (terminal MAC layer 1213).

When the base station MAC layer 1033 completes transmission of data to the terminal MAC layer 1213, the terminal MAC layer 1213 transmits the transmission completion data to the terminal RLC layer 1212. At the same time, the terminal MAC layer 1213 transmits a transmission completion notification to the base station MAC layer 1033. After that, the terminal RLC layer 1212 notifies the base station RLC layer 1032 that the data has been normally received.

If a transmission error occurs between the base station MAC layer 1033 and the terminal MAC layer 1213, the terminal MAC layer 1213 cannot transmit data to the terminal RLC layer 1212. Therefore, if a transmission error occurs between the base station MAC layer 1033 and the terminal MAC layer 1213, the terminal MAC layer 1213 cannot transfer data to the terminal RLC layer and the terminal PDCP layer 1211 above it.

In LTE, the order of data arrival is guaranteed even when retransmission occurs (RLC ACK (Acknowledgement) mode). Therefore, when a packet is retransmitted between the base station RLC layer 1032 and the terminal RLC layer 1212, even if the succeeding packet arrives normally at the terminal RLC layer 1212, the succeeding packet is received until the reception of the retransmitted packet is completed. Data is not transferred to the terminal PDCP layer 1211. Further, no data is transferred to the terminal transport layer 1210, which is higher than the terminal PDCP layer 1211. Therefore, the terminal transport layer 1210 cannot transmit the notification (ACK) indicating that the data has been received to the TCP transmission device.

In addition, TCP congestion control has a function to limit the amount of unconfirmed ACK data during transmission to the upper limit, so unless a transmission completion notification (ACK) is received from the terminal transport layer 1210, the transmitting device will use new data. Do not send. Therefore, when the packet between the base station RLC layer 1032 and the terminal RLC layer 1212 is retransmitted, the subsequent data is not transmitted until the transmitting device receives the ACK packet.

On the other hand, when the packet between the base station RLC layer 1032 and the terminal RLC layer 1212 is retransmitted, there is a function of sequentially transmitting the packet after the packet retransmitted to the base station RLC layer 1032 and the terminal RLC layer 1212. The purpose is not to stop data transmission between the base station 103 and the terminal device even if the RLC layer or the MAC layer is retransmitted. Therefore, even if retransmission occurs between the RLC layers, the data stored in the transmission buffer of the base station 103 (buffer of the base station PDCP layer 1031) is sequentially transmitted. As a result, the amount of data stored in the transmission buffer of the base station 103 (the amount of data staying in the transmission buffer of the so-called base station 103) is reduced.

As a result, a problem occurs between the terminal transport layer 1210 of the terminal device on the transmitting side and the base station RLC layer 1032. When a problem occurs between the terminal transport layer 1210 of the terminal device on the transmitting side and the base station RLC layer 1032, when RLC retransmission occurs, the terminal transport layer 1210 of the terminal device on the transmitting side receives ACK. Unable to send new data. As a result, the amount of data stored in the buffer of the base station 103 (hereinafter referred to as the transmission buffer of the base station 103) decreases and is exhausted. In order to avoid this, a method in which the base station 103 notifies the terminal device on the transmitting side of the buffer status has been proposed [Patent Document 2], but implements a function capable of notifying the base station of the buffer status. Not only that, it is necessary to implement a function that can receive the buffer state notified to the terminal device on the transmitting side, and the problem cannot be solved by the device alone. In addition, the practical cost is high. Further, according to Patent Document 2, the base station information can be notified to the transmitting side, but since the radio information is notified on the ACK, the transmitting device cannot transmit new data until the ACK is received, and the problem cannot be solved. If this state continues and the amount of data stored in the transmission buffer of the base station 103 becomes zero, even if the radio band has a transmission capacity, there is no data to be transmitted, so that the communication speed deteriorates. ..

In the technique of Patent Document 1, the timing of additional transmission of data is determined by using the change in the relationship between the congestion window size of TCP in the communication device and the reception window size notified by the terminal by TCP ACK. As described above, retransmission in the RLC layer suddenly occurs triggered by an error in wireless transmission. Therefore, the communication device described in Patent Document 1 cannot detect that the data in the buffer of the base station has decreased to 0 even if the changes in the congestion window size and the reception window size are observed. As a result, the communication device described in Patent Document 1 cannot additionally transmit data, and the communication speed may deteriorate.

Further, a method of executing additional data transmission processing simply by increasing the communication delay can be considered. However, when such a method is used, the communication device cannot appropriately set the timing for starting the additional data transmission process and the amount of data to be additionally transmitted.

If the amount of data for additional transmission becomes too small, the communication speed may deteriorate due to the data in the base station buffer becoming 0. On the other hand, if the amount of data for additional transmission becomes excessive, the amount of data exceeding the wireless transmission capacity may be transmitted, which may cause deterioration of communication quality due to an increase in packet loss and communication delay.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a communication device, a communication system, a communication method, and a program that contribute to preventing deterioration of communication speed.

According to the first aspect, a communication device is provided. The communication device transmits data to the terminal device via the base station.
The communication device includes a response signal receiving unit that receives an acknowledgment from the terminal device.
Further, the wireless communication speed between the base station and the terminal device is calculated, the amount of data accumulated in the transmission buffer of the base station is calculated as the accumulated data amount, and the wireless communication speed, the accumulated data amount, and the said. A buffer status estimation unit that predicts fluctuations in the amount of stagnant data based on the reception time of the confirmation response is provided.
Further, the communication device includes a transmission time calculation unit that calculates a time at which new data is transmitted to the terminal device as an additional transmission time based on the fluctuation predicted by the buffer status estimation unit.
Further, the communication device includes a new data transmission unit that transmits the new data to the terminal device at a predetermined transmission rate, provided that at least the additional transmission time has elapsed.

From a second perspective, a communication system is provided. The communication system includes a terminal device, a base station, and a communication device.
The terminal device includes a terminal device communication unit connected to a network.
The base station includes a transmission buffer for storing data to be transmitted in the terminal device.
The communication device transmits data to the terminal device via the base station.
Further, the communication device includes a response signal receiving unit that receives an acknowledgment from the terminal device.
Further, the communication device calculates the wireless communication speed between the base station and the terminal device, calculates the amount of data accumulated in the transmission buffer of the base station as the accumulated data amount, and calculates the wireless communication speed and the said. A buffer status estimation unit that predicts fluctuations in the amount of stagnant data based on the amount of stagnant data and the reception time of the confirmation response is provided.
Further, the communication device includes a transmission time calculation unit that calculates a time at which new data is transmitted to the terminal device as an additional transmission time based on the fluctuation predicted by the buffer status estimation unit.
Further, the communication device includes a new data transmission unit that transmits the new data to the terminal device at a predetermined transmission rate, provided that at least the additional transmission time has elapsed.

According to the third viewpoint, a communication method is provided. The communication method includes a step of receiving an acknowledgment from a terminal device.
Further, the communication method includes a step of calculating a wireless communication speed between the base station and the terminal device.
Further, the communication method includes a step of calculating the amount of data accumulated in the transmission buffer of the base station as the amount of accumulated data.
Further, the communication method includes a step of predicting a fluctuation of the stagnant data amount based on the radio communication speed, the stagnant data amount, and the reception time of the confirmation response.
Further, the communication method includes a step of calculating a time at which new data is transmitted to the terminal device as an additional transmission time based on the fluctuation.
Further, the communication method includes a step of transmitting the new data to the terminal device at a predetermined transmission rate, provided that at least the additional transmission time has elapsed.
It should be noted that this method is linked to a specific machine called a communication device that transmits data to a terminal device via a base station.

According to the fourth perspective, the program is provided. The program is a program to be executed by a computer that controls a communication device that transmits data to a terminal device via a base station.
The program causes the computer to execute a process of receiving an acknowledgment from the terminal device.
Further, the communication method causes the computer to execute a process of calculating the wireless communication speed between the base station and the terminal device.
Further, in the communication method, the computer is made to execute a process of calculating the amount of data accumulated in the transmission buffer of the base station as the amount of accumulated data.
The program causes the computer to execute a process of predicting fluctuations in the amount of stagnant data based on the radio communication speed, the amount of stagnant data, and the reception time of the confirmation response.
The program causes the computer to execute a process of calculating a time at which new data is transmitted to the terminal device as an additional transmission time based on the fluctuation.
The program causes the computer to execute a process of transmitting the new data to the terminal device at a predetermined transmission rate, provided that at least the additional transmission time has elapsed.
This program can be recorded on a storage medium that can be read by a computer. The storage medium may be a non-transient such as a semiconductor memory, a hard disk, a magnetic recording medium, or an optical recording medium. The present invention can also be embodied as a computer program product.

According to each viewpoint, communication devices, communication systems, communication methods and programs that contribute to preventing deterioration of communication speed are provided.

It is a figure for demonstrating the outline of one Embodiment. It is a block diagram which shows an example of a protocol configuration example. It is a figure which shows an example of the whole structure of the wireless communication system which concerns on 1st Embodiment. It is a block diagram which shows an example of the hardware composition of the communication apparatus 11 which concerns on 1st Embodiment. It is a block diagram which shows an example of the hardware composition of the terminal apparatus 12 which concerns on 1st Embodiment. It is a block diagram which shows an example of the structure of the communication apparatus 11 which concerns on 1st Embodiment. It is a block diagram which shows an example of the structure of the response signal receiving part 111. It is a flowchart which shows an example of the operation of the communication apparatus 11 which concerns on 1st Embodiment. It is a figure which shows an example of the processing time. It is a block diagram which shows an example of the structure of the communication device 21 which concerns on 2nd Embodiment. It is a flowchart which shows an example of the operation of the communication apparatus 21 which concerns on 2nd Embodiment.

First, an outline of one embodiment will be described with reference to FIG. It should be noted that the drawing reference reference numerals added to this outline are added to each element for convenience as an example for assisting understanding, and the description of this outline is not intended to limit anything. Further, the connection line between the blocks in each block diagram includes both bidirectional and unidirectional. The one-way arrow schematically shows the flow of the main signal (data), and does not exclude bidirectionality. Further, in the circuit diagram, block diagram, internal configuration diagram, connection diagram, etc. shown in the disclosure of the present application, although not explicitly stated, an input port and an output port exist at the input end and the output end of each connection line, respectively. The same applies to the input / output interface.

As described above, a communication device that contributes to preventing deterioration of communication speed is desired.

Therefore, as an example, the communication device 1 shown in FIG. 1 is provided. The communication device 1 transmits data to the terminal device via the base station. The communication device 1 includes a response signal receiving unit 2, a buffer status estimation unit 3, a transmission time calculation unit 4, and a new data transmission unit 5.

The response signal receiving unit 2 receives the confirmation response from the terminal device.

The buffer status estimation unit 3 calculates the wireless communication speed between the base station and the terminal device, calculates the amount of data transmitted by the base station as the amount of stagnant data, and receives the wireless communication speed, the amount of stagnant data, and the confirmation response. Predict fluctuations in the amount of stagnant data based on the time.

The transmission time calculation unit 4 calculates the time at which new data is transmitted to the terminal device as an additional transmission time based on the fluctuation of the retention data of the base station predicted by the buffer status estimation unit 3. In the following description, the process of transmitting additional data is also referred to as the process of transmitting additional data.

The new data transmission unit 5 transmits new data to the terminal device at a predetermined transmission rate, provided that at least the additional transmission time has elapsed.

That is, the communication device 1 determines the timing of transmitting new data in consideration of the amount of stagnant data of the base station, with at least the case where the additional transmission time has elapsed as a necessary condition. Therefore, the communication device 1 contributes to prevent the transmission buffer of the base station from becoming empty. As a result, the communication device 1 contributes to prevent new data from becoming untransmittable in the wireless layer. Therefore, the communication device 1 contributes to prevent deterioration of the communication speed.

[First Embodiment]
The first embodiment will be described in detail with reference to the drawings.

FIG. 3 is a diagram showing an example of the overall configuration of the wireless communication system according to the first embodiment.

The wireless communication system according to the first embodiment includes a network 101-1 to 101-n (n is a natural number; hereinafter the same). The network 101-1-101-n includes communication types (wired or wireless) of different terminal terminals. The network 101-1-11-1n is, for example, an LTE public mobile phone network, a home Wi-Fi (Wireless Fidelity) (registered trademark, the same applies hereinafter), a LAN (Local Area Network) in a building, or the like.

For example, networks 101-1 and 101-2 are mobile networks. The terminal device 12-1 is connected to the network 101-1 via the base station 103-1. The terminal device 12-2 is connected to the network 101-2 via the base station 103-2. In the following description, the terminal devices 12-1 and 12-2 are referred to as terminal devices 12 when it is not necessary to distinguish them from each other. Further, in the following description, the base stations 103-1 and 103-2 will be referred to as a base station 103 when it is not necessary to distinguish them from each other. Further, in the following description, when it is not necessary to distinguish between networks 101-1 to 101-n, they are referred to as network 101.

The terminal device 12 accesses the server 105 on the Internet 104 via the corresponding network 101 and performs data communication. The communication device 11 of the present invention is not applied only to the terminal device 12 using the LTE network, and also supports terminals using other wireless communication formats. For example, the terminal device 12 may communicate with the communication device 11 via the Wi-Fi repeater station. Hereinafter, for convenience of explanation, the terminal device 12 will be described by way of exemplifying a case where an LTE network is used. However, this is not intended to be limited to the case where the terminal device 12 according to the present embodiment uses the LTE network.

In the present embodiment, the case where the communication device 11 is installed at the connection portion between the network 101 and the Internet 104 on the communication path will be taken as an example. Of course, the installation location of the communication device 11 is not limited to the connection portion between the mobile network and the Internet, and may be a device on a communication path other than the connection portion. For example, the communication device 11 may be installed on the server 105 on the communication path.

[Hardware configuration]
Next, the hardware configurations of the various devices according to the first embodiment will be described. FIG. 4 is a block diagram showing an example of the hardware configuration of the communication device 11 according to the first embodiment.

[Communication device configuration]
The communication device 11 is configured to include, for example, the configuration illustrated in FIG. For example, the communication device 11 includes a CPU (Central Processing Unit) 81, a memory 82, an input / output interface 83, and a NIC (Network Interface Card) 84 which is a communication means, which are connected to each other by an internal bus.

However, the configuration shown in FIG. 4 is not intended to limit the hardware configuration of the communication device 11. The communication device 11 may include hardware (not shown), or may not include an input / output interface 83 if necessary. Further, the number of CPUs and the like included in the communication device 11 is not limited to the example of FIG. 4, and for example, the communication device 11 may be configured to include a plurality of CPUs.

The memory 82 is a RAM (Random Access Memory), a ROM (Read Only Memory), and an auxiliary storage device (hard disk or the like).

The input / output interface 83 functions as an interface of a display device or an input device (not shown). The display device is, for example, a liquid crystal display or the like. The input device accepts user operations such as a keyboard and a mouse.

The function of the communication device 11 is realized by various processing modules described later. The processing module is realized, for example, by the CPU 81 executing a program stored in the memory 82. In addition, the program can be downloaded via a network or updated using a storage medium in which the program is stored. Further, the processing module may be realized by a semiconductor chip. That is, the communication device 11 is configured to include means for executing the function performed by the processing module by some hardware and / or software.

[Terminal device configuration]
The terminal device 12 includes, for example, the configuration illustrated in FIG. The terminal device 12 includes an RF (Radio Frequency) circuit 94 including an antenna 95. The RF circuit 94 is a circuit for realizing wireless communication, and exchanges wireless signals with and from the base station 103 via the antenna 95. Of the hardware included in the terminal device 12, the description of the hardware common to the communication device 11 will be omitted.

Since the hardware configuration of the base station 103 is obvious to those skilled in the art, the description thereof will be omitted.

Subsequently, the processing configuration (processing module) of the communication device 11 and the terminal device 12 will be described.

FIG. 6 is a block diagram showing a configuration example of a system including a communication device 11, a terminal device 12, and a network 101. The terminal device 12 includes a terminal device communication unit 121. The network 101 includes a base station 103. The communication device 11 includes a response signal receiving unit 111, a buffer status estimation unit 112, a transmission time calculation unit 113, and a new data transmission unit 114.

The terminal device communication unit 121 of the terminal device 12 is communicably connected to the base station 103 of the network 101. The network 101 is communicably connected to the response signal receiving unit 111 of the communication device 11. The response signal receiving unit 111 is communicably connected to the buffer status estimation unit 112, the transmission time calculation unit 113, and the new data transmission unit 114. The transmission time calculation unit 113 is communicably connected to the buffer status estimation unit 112 and the new data transmission unit 114.

The response signal receiving unit 111 receives the response signal from the terminal device 12.

The buffer status estimation unit 112 determines the transmission buffer of the base station 103 based on the wireless communication speed between the base station 103 and the terminal device 12, the amount of data retained in the transmission buffer of the base station 103, and the reception time of the acknowledgment. Predict fluctuations in the amount of retained data within.

The transmission time calculation unit 113 calculates the additional transmission time of new data to the terminal device 12 based on the fluctuation of the amount of accumulated data in the transmission buffer of the base station 103.

The new data transmission unit 114 transmits new data to the terminal device 12 at a predetermined transmission rate at least when the additional transmission time has elapsed.

Hereinafter, the configuration of the communication device 11 will be described in more detail with reference to FIG. 7.

FIG. 7 is a block diagram showing an example of the configuration of the response signal receiving unit 111 shown in FIG. The response signal receiving unit 111 is configured to include a general configuration of an OSI (Open Systems Interconnection) reference model. Specifically, the response signal receiving unit 111 includes a communication device application layer 1110, a communication device transport layer 1111, a communication device network layer 1112, a communication device MAC layer 1113, and a communication device physical layer 1114. It is composed. Note that FIG. 7 relates to a configuration other than the configuration related to the response signal receiving unit 111 in order to clarify the connection relationship between the buffer status estimation unit 112, the transmission time calculation unit 113, and the new data transmission unit 114. The description is omitted.

The buffer status estimation unit 112 calculates the buffer status of the base station 103 based on the information (for example, transmission packet, reception packet) obtained from the communication device transport layer 1111 of the response signal reception unit 111. Specifically, the buffer status estimation unit 112 calculates the time at which the amount of stagnant data in the base station 103 is estimated to be equal to or less than a predetermined threshold value as the buffer exhaustion time. After that, the buffer status estimation unit 112 transmits the calculated buffer exhaustion time to the transmission time calculation unit 113.

Further, the buffer status estimation unit 112 is not limited to being connected to the communication device transport layer 1111 but may be connected to another layer of the response signal receiving unit 111 (for example, the communication device application layer 1110). For example, in a communication protocol based on UDP such as QUIC, the acknowledgment signal is not transmitted to the communication device transport layer 1111 but is transmitted to the communication device application layer 1110.

The transmission time calculation unit 113 calculates an additional transmission time based on the transmission delay between the self-communication device 11 and the terminal device 12, the reception time of the acknowledgment, and the buffer exhaustion time. The transmission time calculation unit 113 transmits the calculated additional transmission time to the new data transmission unit 114. Further, the transmission time calculation unit 113 calculates the transmission rate of the additional transmission (hereinafter referred to as the additional transmission rate).

The new data transmission unit 114 transmits data to the terminal device 12 via the base station 103 based on the additional transmission time received from the transmission time calculation unit 113 and the additional transmission rate received from the transmission time calculation unit 113. Send.

[Operation of communication device]
FIG. 8 is a flowchart showing an example of the operation of the communication device 11 according to the first embodiment.

First, the terminal device 12 starts data communication with the communication device 11. The communication protocol between the communication device 11 and the terminal device 12 according to the present embodiment is a protocol having a response confirmation function. For example, the communication protocol between the communication device 11 and the terminal device 12 according to the present embodiment may be TCP or the like for transmitting an acknowledgment in the communication device transport layer 1111. Of course, the communication protocol between the communication device 11 and the terminal device 12 according to the present embodiment is not limited to the protocol for transmitting the acknowledgment in the communication device transport layer 1111, and corresponds to the protocol for transmitting the acknowledgment in the other layers. You may.

The buffer status estimation unit 112 acquires the round-trip delay, the amount of in-flight data, the TCP throughput, and the like as communication information from the response signal receiving unit 111 (step S11). Here, the amount of in-flight data means the amount of unconfirmed data that has been successfully transmitted and successfully received in TCP. Further, here, the TCP throughput means the throughput within the latest predetermined time in TCP.

For example, the buffer status estimation unit 112 may use the value obtained by dividing the total number of bits of the received packet by the predetermined time within the latest predetermined time as the TCP throughput. Alternatively, the buffer status estimation unit 112 may calculate the TCP throughput per unit time and use the calculated average value of the TCP throughput per unit time. Alternatively, the buffer status estimation unit 112 may calculate the TCP throughput per unit time and use the calculated moving average value of the TCP throughput per unit time.

Then, the buffer status estimation unit 112 calculates the amount of stagnant data in the base station 103 and the buffer exhaustion time (step S12). Specifically, the buffer status estimation unit 112 uses the acquired communication information to calculate the amount of stagnant data in the base station 103 and the buffer exhaustion time. Then, the buffer status estimation unit 112 transmits the calculated buffer exhaustion time to the transmission time calculation unit 113.

For example, the buffer status estimation unit 112 may calculate the amount of stagnant data of the base station 103 based on the amount of transmission data transmitted by the self-communication device 11 and the amount of reception data received by the terminal device 12. Here, the terminal device 12 may notify the communication device 11 of the upper limit of the amount of data that the terminal device 12 can receive. For example, the buffer status estimation unit 112 may use the value described in the TCP header as the upper limit value of the amount of data that can be received by the terminal device 12.

Alternatively, the buffer status estimation unit 112 may calculate the amount of stagnant data based on the upper limit of the reception window size of the terminal device 12.

Alternatively, the buffer status estimation unit 112 may calculate the stagnant data amount of the base station 103 based on the upper limit value of the stagnant data amount of the transmission buffer of the base station 103.

Then, after T seconds from the reference time (T is an integer larger than 0; the same applies hereinafter), the amount of retained data in the transmission buffer of the base station 103 becomes equal to or less than a predetermined threshold value (for example, becomes zero). It is assumed that the buffer status estimation unit 112 has calculated. In that case, the buffer status estimation unit 112 calculates the time T seconds after the reference time as the buffer exhaustion time. Here, the reference time may be, for example, the time at which the buffer status estimation unit 112 calculates the buffer depletion time. Further, the reference time may be, for example, the latest time when the communication device 11 transmitted the data.

Here, when the communication device 11 does not transmit new data to the base station 103, the amount of accumulated data in the transmission buffer of the base station 103 is consumed at a predetermined speed. Therefore, the buffer status estimation unit 112 may calculate the buffer exhaustion time by dividing the amount of accumulated data in the transmission buffer of the base station 103 and the wireless communication speed.

The buffer status estimation unit 112 calculates the amount of accumulated data or the wireless communication speed in the transmission buffer of the base station 103 based on the communication information acquired by the terminal device 12 on the transmitting side or the communication information acquired by the communication device 11. You may.

Further, for example, the buffer status estimation unit 112 may use the TCP throughput within the latest predetermined time as an approximate value of the wireless communication speed.

Further, for example, the buffer status estimation unit 112 may calculate a value calculated in consideration of the carrier aggregation status based on the TCP throughput within the latest predetermined time as an approximate value of the wireless communication speed. When LTE carrier aggregation technology is applied, the frequency of occurrence of radio communication speed deterioration increases. Therefore, the buffer status estimation unit 112 calculates the TCP throughput for the latest predetermined time and the number of component carriers used by the terminal device 12 for the terminal device 12 to which the carrier aggregation technique is applied. As a result, the buffer status estimation unit 112 calculates an approximate value of the wireless communication speed.

For example, the buffer status estimation unit 112 may calculate an approximate value of the wireless communication speed by using the TCP throughput * f (N_CC).

Here, f (N_CC) is a TCP throughput corresponding to the number of component carriers used by the terminal device 12. The buffer status estimation unit 112 may calculate an approximate value of the wireless communication speed by using different TCP throughput for each number of component carriers (for example, f (1) = 1.0, f (2) = 1.02, f (3) = 1.04 etc.).

Further, the buffer status estimation unit 112 uses carrier aggregation technology to estimate the number of component carriers used by the terminal device 12. In that case, as the number of component carriers increases, the frequency of deterioration of the wireless communication speed increases. Therefore, the buffer status estimation unit 112 utilizes this characteristic to estimate the number of component carriers based on the frequency (number of occurrences within a predetermined time) that the arrival interval of the acknowledgment (for example, ACK signal) exceeds a certain threshold value. You may.

After that, the transmission time calculation unit 113 calculates the additional transmission time (step S13). Specifically, the transmission time calculation unit 113 considers the time (that is, transmission delay) until the data transmitted by the new data transmission unit 114 arrives at the transmission buffer of the base station 103 from the response signal reception unit 111. , Calculate additional transmission time. This is to prevent the buffer of the base station 103 from becoming empty.

For example, the transmission time calculation unit 113 calculates half of the round-trip delay (RTT / 2) as the transmission delay based on the round-trip delay (RTT) between the communication device 11 and the terminal device 12.

The transmission time calculator 113 may use the current TCP session, or the smallest RTT in a plurality of TCP sessions for the same terminal device 12, or the smallest RTT in the most recent time, for the round trip delay. As a result, the transmission time calculation unit 113 can utilize the effective minimum delay excluding the queuing delay of the base station 103.

Further, the transmission time calculation unit 113 may calculate the transmission delay based on the time stamp described in the packet. For example, as shown in FIG. 9, the time when the communication device 11 transmits the packet is Ta, and the time when the communication device 11 receives the packet is Tb. In that case, the RTT is Tb-Ta. However, in the terminal device 12, it takes a processing time to process the received packet. Therefore, the transmission time calculation unit 113 removes the processing time (Ty-Tx) of the terminal device 12 when calculating the effective one-way delay. Therefore, when the terminal device 12 describes the Tx and Ty times in the packet, the transmission time calculation unit 113 uses ((Tb-Ta)-(Ty-Tx)) to receive the response signal as the transmission data. The time from the unit 111 to the arrival at the transmission buffer of the base station 103 is calculated. For example, the terminal device 12 may describe the time Tx and the time Ty in the packet by using the option field of the TCP header.

In step S14, the transmission time calculation unit 113 determines whether or not the additional transmission time is exceeded and the response signal reception unit 111 has not received the new ACK.

When the additional transmission time is exceeded and the response signal receiving unit 111 has not received a new ACK during the measurement period (Yes branch in step S14), the transmission time calculation unit 113 performs additional transmission processing. To execute. Then, the process proceeds to step S15.

For example, when the response signal receiving unit 111 receives the ACK signal, the transmission time calculation unit 113 may activate the timer. Then, the transmission time calculation unit 113 may measure the elapsed time from the start of the timer.

On the other hand, if the response signal receiving unit 111 receives a new ACK by the time the additional transmission time is exceeded (No branch in step S14), the process returns to step S12 and the process is continued.

Next, with reference to FIG. 2, the process of determining the necessity of additional transmission by the transmission time calculation unit 113 will be described in detail.

In the LTE standard model, when a transmission error occurs between an arbitrary base station MAC layer 1033 and the terminal MAC layer 1213, an extension of the ACK reception interval of the terminal transport layer 1210 occurs. In the terminal transport layer 1210, if the terminal device 12 cannot receive the TCP ACK within a predetermined time, the terminal device communication unit 121 estimates that the base station RLC layer 1032 is performing retransmission.

In this case, the terminal device communication unit 121 cannot receive TCP ACK. However, the buffer status estimation unit 112 estimates that the amount of accumulated data in the transmission buffer of the base station 103 is gradually decreasing. Therefore, the transmission time calculation unit 113 determines whether or not additional transmission is necessary.

Further, the buffer status estimation unit 112 may estimate the amount of retained data in the transmission buffer of the base station 103 by using an acknowledgment of another protocol instead of TCP ACK. For example, the buffer status estimation unit 112 may estimate the amount of retained data in the transmission buffer of the base station 103 using the response signals of QUIC (Quick UDP Internet Connections) and MQTT (Message Queue Telemetry Transport). When the communication device 11 uses a response signal of another protocol, the response signal is not limited to being transmitted to the terminal transport layer 1210, and may be transmitted to another layer (for example, an application layer). Hereinafter, for convenience of explanation, a case where a response signal is transmitted by using TCP of the terminal transport layer 1210 will be described. However, this is not limited to the case where the terminal device 12 according to the present embodiment transmits a response signal by using the TCP of the terminal transport layer 1210.

The transmission time calculation unit 113 measures the elapsed time since the response signal reception unit 111 received the latest ACK. Further, when a plurality of TCP sessions for the same terminal device 12 simultaneously communicate with the communication device transport layer 1111, the transmission time calculation unit 113 is the elapsed time from the time when the latest ACK is received among the plurality of TCP sessions. To measure. Further, the transmission time calculation unit 113 may measure the elapsed time since the response signal reception unit 111 transmits the latest packet.

In step S15, the transmission time calculation unit 113 calculates the transmission rate.

For example, the wireless communication speed within the latest predetermined time may be calculated as the transmission rate. Further, the transmission time calculation unit 113 may estimate the transmission rate by using other communication characteristics.

Further, for example, the transmission time calculation unit 113 may approximate the TCP throughput within the latest predetermined time or the TCP transmission rate within the latest predetermined time and calculate the transmission rate. Further, the transmission time calculation unit 113 may calculate the transmission rate by using the maximum TCP throughput during the TCP session or the maximum TCP throughput within the latest predetermined time.

Further, it is assumed that the communication device 11 has set up a plurality of TCP sessions with the same terminal device 12. In that case, the transmission time calculation unit 113 calculates the transmission rate using the maximum value of the total of the TCP throughputs of the plurality of TCP sessions or the total of the TCP throughputs of the plurality of TCP sessions within the latest predetermined time. May be good.

Further, when carrier aggregation technology is applied, the frequency of occurrence of deterioration of wireless communication speed increases. Therefore, the communication device 11 may transmit at a higher transmission rate to the terminal device 12 to which the carrier aggregation technique is applied.

The transmission time calculation unit 113 calculates the transmission rate using, for example, the same calculation as when the buffer status estimation unit 112 approximates the radio communication speed. After that, the transmission time calculation unit 113 transmits the calculated transmission rate to the new data transmission unit 114.

In step S16, the new data transmission unit 114 transmits new data.

Generally, in TCP, for congestion control, there is a mechanism for suppressing the amount of unconfirmed data to a predetermined value even if the amount of data is successfully transmitted. Specifically, in general, in TCP, the in-flight amount of data is controlled so as not to exceed the congestion window (cwnd) size. Further, in general, in TCP, control is performed so as not to exceed the receive window (rwnd) size included in the header of the ACK packet returned from the receiving side.

On the other hand, the communication device 11 according to the present embodiment has a congestion window (cwnd) size, a reception window (rwnd) size included in the header of the ACK packet, an upper limit of the buffer of the communication device transport layer 1111, or a base. Data exceeding at least one value of the upper limit of the transmission buffer of the station 103 can be transmitted. Therefore, when transmitting new data, the new data transmission unit 114 ignores restrictions on the congestion window (cwnd) size, the reception window (rwnd) size included in the header of the ACK packet, or the buffer size of the transmission buffer. Data can be sent.

[effect]
As described above, in the communication device 11 according to the first embodiment, it is estimated that the amount of accumulated data in the transmission buffer of the base station 103 is equal to or less than a predetermined threshold value based on the radio communication characteristics of the base station 103. Predict the time (ie, the buffer depletion time). After that, before the amount of accumulated data in the transmission buffer of the base station 103 becomes equal to or less than a predetermined threshold value (for example, becomes zero), the communication device 11 passes through the new data transmission unit 114 and sends new data to the base station 103. Is additionally sent. Thereby, the communication device 11 according to the present embodiment can maintain the amount of retained data in the transmission buffer of the base station 103 at a data amount larger than a predetermined threshold value (for example, larger than zero). As a result, the communication device 11 contributes to preventing new data from becoming untransmittable in the wireless layer. As a result, the communication device 11 can prevent deterioration of communication performance.

[Second Embodiment]
Next, the second embodiment will be described in detail with reference to the drawings. In this embodiment, information about the base station is acquired from the base station, and the acquired information is used to predict the buffer depletion time. In the description of the present embodiment, the description of the portion overlapping with the above-described embodiment will be omitted. Further, in the description of the present embodiment, the same components as those of the above embodiment are designated by the same reference numerals, and the description thereof will be omitted. Further, in the description of the present embodiment, the description of the same effects as those of the above-described embodiment will be omitted.

[Communication device configuration]
FIG. 10 is a diagram showing an example of the configuration of the communication device 21 according to the second embodiment.

The base station information acquisition unit 215 acquires information about the base station 103 (hereinafter referred to as base station information) from the base station 103. For example, the base station information acquisition unit 215 determines the upper limit of the transmission buffer of the base station 103 (hereinafter, also referred to as the upper limit of the buffer size) and the amount of data retained in the transmission buffer of the base station 103 as base station information. May be obtained as. Further, for example, the base station information acquisition unit 215 acquires the radio communication speed between the base station 103 and the terminal device 12, the number of communication radio waves (carrier aggregation status) between the base station 103 and the terminal device 12, and the base station information. You may. Then, the base station information acquisition unit 215 transmits the acquired base station information to the buffer status estimation unit 212.

Since the response signal receiving unit 211 has the same configuration as the response signal receiving unit 111 according to the first embodiment, the description thereof will be omitted.

Since the transmission time calculation unit 213 has the same configuration as the transmission time calculation unit 113 according to the first embodiment, the description thereof will be omitted.

Since the new data transmission unit 214 has the same configuration as the new data transmission unit 114 according to the first embodiment, the description thereof will be omitted.

[Operation of communication device]
FIG. 11 is a flowchart showing an example of the operation of the communication device 21 according to the second embodiment.

First, the base station information acquisition unit 215 acquires base station information from the base station 103 (step S21). For example, the base station information acquisition unit 215, from the base station 103, sets the upper limit value of the transmission buffer (upper limit value of the buffer size), the amount of data staying in the transmission buffer, the wireless communication speed with the terminal device 12, and the terminal device 12. At least one of the communication radio wave numbers (carrier aggregation status) of the above is acquired. Then, the base station information acquisition unit 215 transmits the acquired information from the base station 103 to the buffer status estimation unit 212.

The buffer status estimation unit 212 acquires the round-trip delay, the in-flight data amount, and the TCP throughput from the response signal reception unit 211 as communication information (step S22).

The buffer status estimation unit 212 calculates the amount of stagnant data in the base station 103 and the buffer exhaustion time (step S23). Specifically, the buffer status estimation unit 212 uses the communication information acquired from the response signal reception unit 211 and the base station information acquired from the base station information acquisition unit 215, and the amount of stagnant data of the base station 103 and the retention data. Calculate the buffer depletion time.

For example, the buffer status estimation unit 212 combines the communication information acquired from the response signal reception unit 211 and the base station information acquired from the base station information acquisition unit 215 to determine the amount of stagnant data in the base station 103 and the buffer depletion time. May be calculated. Alternatively, the buffer status estimation unit 212 uses one of the communication information acquired from the response signal reception unit 211 and the base station information acquired from the base station information acquisition unit 215 to retain the base station 103. The amount of data and the time when the buffer is exhausted may be calculated.

For example, when there is no new data, the amount of accumulated data in the transmission buffer of the base station 103 is consumed at a predetermined speed. Therefore, the buffer status estimation unit 212 can calculate the buffer depletion time by dividing the amount of stagnant data and the wireless communication speed. Specifically, the buffer status estimation unit 212 estimates the amount of accumulated data in the transmission buffer of the base station 103 and the wireless communication speed. Then, the buffer status estimation unit 212 calculates the buffer depletion time by calculating the time when the estimated accumulated data amount is transmitted, assuming that the data is transmitted at the estimated wireless communication speed.

The buffer status estimation unit 212 calculates the amount of accumulated data in the transmission buffer of the base station 103 and the wireless communication speed by using the base station information acquired from the base station information acquisition unit 215. For example, the buffer status estimation unit 212 uses at least one of the amount of accumulated data in the transmission buffer of the base station 103 acquired from the base station information acquisition unit 215 and the upper limit value of the transmission buffer of the base station 103. The amount of stagnant data in the transmission buffer of the base station 103 is calculated.

Further, for example, the buffer status estimation unit 212 may use the wireless communication speed between the base station 103 and the terminal device 12 acquired from the base station information acquisition unit 215, or the maximum wireless communication speed within a predetermined time.

Then, it is assumed that the buffer status estimation unit 212 calculates that the amount of retained data in the transmission buffer of the base station 103 becomes equal to or less than a predetermined threshold value (for example, becomes zero) after the lapse of time T seconds from the reference time. In that case, the buffer status estimation unit 212 calculates the time after T seconds have elapsed from the reference time as the buffer exhaustion time. Then, the buffer status estimation unit 212 transmits the calculated buffer exhaustion time to the transmission time calculation unit 213.

After that, the transmission time calculation unit 213 calculates the additional transmission time (step S24). Specifically, the transmission time calculation unit 213 sets the additional transmission time in consideration of the time (that is, transmission delay) from the response signal reception unit 211 to the arrival of the additional transmission data in the transmission buffer of the base station 103. calculate. Here, the transmission time calculation unit 213 may calculate the additional transmission time by using the information notified from the base station 103. For example, the transmission time calculation unit 213 uses the round-trip delay between the base station 103 and the terminal device 12, the one-way delay, or the time stamp described in the information notified from the base station 103 to set the additional transmission time. It may be calculated.

The transmission time calculation unit 213 measures the elapsed time since the response signal reception unit 211 received the latest ACK. Further, in the communication device transport layer 1111, when a plurality of TCP sessions to the same terminal device 12 communicate at the same time, the transmission time calculation unit 213 has elapsed time from the time when the latest ACK was received among the plurality of TCP sessions. To measure. Further, the transmission time calculation unit 213 may measure the elapsed time from the time when the response signal reception unit 211 transmits the latest packet.

In step S25, the transmission time calculation unit 213 determines whether or not the response signal receiving unit 211 has not received a new ACK when the additional transmission time is exceeded and during the measurement period.

When the additional transmission time is exceeded and the response signal receiving unit 211 has not received a new ACK during the measurement period (Yes branch in step S25), the transmission time calculation unit 213 performs additional transmission processing. To execute. Then, the process proceeds to step S26.

For example, when the response signal receiving unit 211 receives the ACK signal, the transmission time calculation unit 213 may start the timer and measure the elapsed time from the start of the timer.

On the other hand, if the response signal receiving unit 211 receives a new ACK (No branch in step S25) while the timer is running before the additional transmission time is exceeded, the process proceeds to step S23 and the process is continued.

In step S26, the transmission time calculation unit 213 calculates the transmission rate.

The transmission time calculation unit 213 calculates, for example, the wireless communication speed within the latest predetermined time as the transmission rate. Further, the transmission time calculation unit 213 may calculate the transmission rate by combining the communication information acquired from the response signal reception unit 211 and the base station information acquired from the base station information acquisition unit 215. Further, the transmission time calculation unit 213 calculates the transmission rate using one of the communication information acquired from the response signal reception unit 211 and the base station information acquired from the base station information acquisition unit 215. You may.

For example, the transmission time calculation unit 213 uses the wireless communication speed between the base station 103 and the terminal device 12 acquired from the base station information acquisition unit 215, or the maximum wireless communication speed within a predetermined time, to set the transmission rate. It may be calculated.

Further, the transmission time calculation unit 213 may calculate the wireless communication speed by using the same method as in the first embodiment. In that case, the transmission time calculation unit 213 may calculate the wireless communication speed by using the base station information acquired from the base station information acquisition unit 215.

For example, the base station information acquisition unit 215 acquires the number of communication radio waves (carrier aggregation status) between the base station 103 and the terminal device 12. Then, the transmission time calculation unit 213 calculates the wireless communication speed based on the TCP throughput of the latest predetermined time and the number of component carriers used by the terminal device 12. After that, the transmission time calculation unit 213 transmits the calculated transmission rate to the new data transmission unit 214.

The new data transmission unit 214 transmits new data (step S27). The new data transmission unit 214 operates in the same manner as the new data transmission unit 114 according to the first embodiment. That is, when transmitting new data, the new data transmission unit 214 can transmit the data ignoring the limitation of the transmission amount, the transmission time, or the communication rate specified by the communication protocol.

[Modification 1]
As a modification 1 of the communication device 21 according to the present embodiment, the response signal receiving unit 211 may receive the wireless communication speed between the base station 103 and the terminal device 12 from the terminal device 12.

As described above, the communication device 21 according to the present embodiment further contributes to prevent deterioration of communication performance as compared with the communication device 11 according to the first embodiment. The reason is that the communication device 21 according to the second embodiment predicts the buffer depletion time based on the base station information acquired from the base station 103. Further, the communication device 21 according to the present embodiment directly acquires the base station information from the base station 103 and calculates the transmission rate, so that the difference between the wireless communication speed acquired from the base station 103 and the calculated transmission rate. Can be reduced. Therefore, the communication device 21 according to the present embodiment can avoid transmitting data by using an under or excessive transmission rate. As a result, the communication device 21 according to the present embodiment contributes to prevent deterioration of the performance of the communication network. Further, the communication device 21 according to the present embodiment contributes to avoiding transmission of a data amount exceeding the capacity of the transmission buffer of the base station 103.

Some or all of the above embodiments may also be described as, but not limited to, the following embodiments.

(Form 1) The communication device according to the first viewpoint.

(Form 2) The buffer status estimation unit calculates a time at which the retention data is estimated to be equal to or less than a predetermined threshold as a buffer exhaustion time, and the transmission time calculation unit transmits between the own communication device and the terminal device. The communication device according to the first embodiment, wherein the additional transmission time is calculated based on the delay, the reception time, and the buffer exhaustion time.

(Form 3) The buffer status estimation unit calculates the stagnant data amount by further using the transmission data amount transmitted by the self-communication device and the received data amount received by the terminal device acquired from the confirmation response signal. The communication device according to the first or second embodiment.

(Form 4) The buffer status estimation unit is based on at least one of an upper limit of the reception window size of the terminal device and an upper limit of the amount of stagnant data in the transmission buffer of the base station. The communication device according to any one of embodiments 1 to 3, preferably for calculating the amount.

(Form 5) The communication device according to any one of Forms 1 to 4, wherein the buffer status estimation unit calculates the wireless communication speed based on the amount of transmission data transmitted by the own communication device.

(Form 6) The communication device according to any one of embodiments 1 to 5, further comprising a base station information acquisition unit that acquires the wireless communication speed from the base station.

(Form 7) In the transmission time calculation unit, at least one of the elapsed time from the reception time of the latest response signal and the elapsed time from the latest data transmission time reaches a preset threshold value. The communication device according to any one of embodiments 1 to 6, wherein the time is determined as the additional transmission time.

(Form 8) The communication device according to any one of embodiments 1 to 7, wherein the transmission time calculation unit calculates a transmission rate based on the wireless communication speed.

(Form 9) This is the same as the communication system according to the second viewpoint.

(Form 10) The buffer status estimation unit calculates a time at which the retention data is estimated to be equal to or less than a predetermined threshold as a buffer exhaustion time, and the transmission time calculation unit transmits between the own communication device and the terminal device. The communication system according to embodiment 9, wherein the additional transmission time is calculated based on the delay, the reception time, and the buffer exhaustion time.

(Form 11) The communication method according to the third viewpoint is as described above.

(Form 12) Transmission between the self-communication device and the terminal device in a step of calculating the additional transmission time, further including a step of calculating a time at which the retention data is estimated to be equal to or less than a predetermined threshold as a buffer exhaustion time. The communication method according to the eleventh embodiment, wherein the additional transmission time is calculated based on the delay, the reception time, and the buffer exhaustion time.

(Form 13) The program is as described in the fourth viewpoint.

(Form 14) In the process of causing the computer to further execute the process of calculating the time at which the stagnant data is estimated to be equal to or less than a predetermined threshold as the buffer exhaustion time and calculating the additional transmission time, the self-communication device and the terminal. The program according to embodiment 13, which calculates the additional transmission time based on the transmission delay between the devices, the reception time, and the buffer exhaustion time.

The forms shown in the above forms 9, 11 and 13 can be developed into the forms shown in the forms 3 to 8 in the same manner as the forms shown in the form 1.

The disclosure of the above patent documents shall be incorporated into this document by citation. Within the framework of the entire disclosure (including the scope of claims) of the present invention, the embodiments can be changed and adjusted based on the basic technical idea thereof. In addition, various combinations or selections (partial) of various disclosure elements (including each element of each claim, each element of each embodiment, each element of each drawing, etc.) within the framework of all disclosure of the present invention. (Including deletion) is possible. That is, it goes without saying that the present invention includes all disclosure including claims, various modifications and modifications that can be made by those skilled in the art in accordance with the technical idea. In particular, with respect to the numerical range described in this document, any numerical value or small range included in the range should be construed as being specifically described even if not otherwise described. In the present invention, it is self-evident that a computer will be used when an algorithm, software, or flowchart or automated process step is shown, and it is also self-evident that the computer will be equipped with a processor and memory or storage device. be. Therefore, even if the specification is lacking, it is understood that these elements are naturally described in the present application.

1,11,21 Communication device 2,111,211 Response signal receiving unit 3,112,212 Buffer status estimation unit 4,113,213 Transmission time calculation unit 5,114,214 New data transmission unit 12,12-1,12 -2 Terminal equipment 81, 91 CPU
82, 92 Memory 83, 93 I / O interface 84 NIC
94 RF circuit 95 Antenna 101, 101-1 to 101-n Network 103, 103-1, 103-2 Base station 104 Internet 105 Server 121 Terminal equipment Communication unit 215 Base station information acquisition unit 1031 Base station PDCP layer 1032 Base station RLC Layers 1033, 1033a, 1033b Base station MAC layer 1034, 1034a, 1034b Base station physical layer 1110 Communication equipment application layer 1111 Communication equipment transport layer 1112 Communication equipment network layer 1113 Communication equipment MAC layer 1114 Communication equipment physical layer 1210 Terminal transport layer 1211 Terminal PDCP layer 1212 Terminal RLC layer 1213, 1213a, 1213b Terminal MAC layer 1214, 1214a, 1214b Terminal physical layer

Claims (10)

A communication device that transmits data to a terminal device via a base station.
A response signal receiving unit that receives an acknowledgment from the terminal device,
The wireless communication speed between the base station and the terminal device is calculated, the amount of data accumulated in the transmission buffer of the base station is calculated as the accumulated data amount, and the wireless communication speed, the accumulated data amount, and the confirmation response are calculated. A buffer status estimation unit that predicts fluctuations in the amount of stagnant data based on the reception time of
A transmission time calculation unit that calculates the time when new data is transmitted to the terminal device as an additional transmission time based on the fluctuation predicted by the buffer status estimation unit.
A new data transmission unit that transmits the new data to the terminal device at a predetermined transmission rate, provided that at least the additional transmission time has elapsed.
A communication device equipped with. The buffer status estimation unit calculates the time when the amount of stagnant data is estimated to be equal to or less than a predetermined threshold value as the buffer exhaustion time.
The communication device according to claim 1, wherein the transmission time calculation unit calculates the additional transmission time based on the transmission delay between the own communication device and the terminal device, the reception time, and the buffer exhaustion time. .. The buffer status estimation unit further uses the amount of transmission data transmitted by the self-communication device and the amount of reception data received by the terminal device acquired from the confirmation response to calculate the amount of stagnant data, claim 1. Or the communication device according to 2. The buffer status estimation unit calculates the stagnant data amount based on at least one of the upper limit value of the reception window size of the terminal device and the upper limit value of the stagnant data amount of the transmission buffer of the base station. , The communication device according to any one of claims 1 to 3. The communication device according to any one of claims 1 to 4, wherein the buffer status estimation unit calculates the wireless communication speed based on the amount of transmission data transmitted by the self-communication device. The communication device according to any one of claims 1 to 5, further comprising a base station information acquisition unit that acquires the wireless communication speed from the base station. The transmission time calculation unit sets the time when one of the elapsed time from the reception time of the latest response signal and the elapsed time from the latest data transmission time reaches a preset threshold value as the additional transmission time. The communication device according to any one of claims 1 to 6. A terminal device that connects to a network and has a terminal device communication unit,
A base station having a transmission buffer for storing data to be transmitted in the terminal device, and
A communication device that transmits data to the terminal device via the base station, the base station, the terminal device, and the like.
Is a communication system including
The communication device is
A response signal receiving unit that receives an acknowledgment from the terminal device,
The wireless communication speed between the base station and the terminal device is calculated, the amount of data accumulated in the transmission buffer of the base station is calculated as the accumulated data amount, and the wireless communication speed, the accumulated data amount, and the confirmation response are calculated. A buffer status estimation unit that predicts fluctuations in the amount of stagnant data based on the reception time of
A transmission time calculation unit that calculates the time when new data is transmitted to the terminal device as an additional transmission time based on the fluctuation predicted by the buffer status estimation unit.
A new data transmission unit that transmits the new data to the terminal device at a predetermined transmission rate, provided that at least the additional transmission time has elapsed.
A communication system equipped with. The step of receiving an acknowledgment from the terminal and
Steps to calculate the wireless communication speed between the base station and the terminal device,
A step of calculating the amount of data accumulated in the transmission buffer of the base station as the amount of accumulated data, and
A step of predicting fluctuations in the amount of stagnant data based on the wireless communication speed, the amount of stagnant data, and the reception time of the confirmation response, and
A step of calculating the time at which new data is transmitted to the terminal device as an additional transmission time based on the fluctuation, and
A step of transmitting the new data to the terminal device at a predetermined transmission rate, provided that at least the additional transmission time has elapsed.
Communication methods including. A program that is executed by a computer that controls a communication device that sends data to a terminal device via a base station.
The process of receiving an acknowledgment from the terminal device and
Processing to calculate the wireless communication speed between the base station and the terminal device,
The process of calculating the amount of data accumulated in the transmission buffer of the base station as the amount of accumulated data, and
Processing for predicting fluctuations in the amount of stagnant data based on the wireless communication speed, the amount of stagnant data, and the reception time of the confirmation response.
Based on the fluctuation, the process of calculating the time when new data is transmitted to the terminal device as the additional transmission time, and
A process of transmitting the new data to the terminal device at a predetermined transmission rate, provided that at least the additional transmission time has elapsed.
A program that causes the computer to execute.

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