WO2019146563A1 - Communication device, communication system, communication method, and program - Google Patents

Abstract

The present invention contributes to the prevention of degradation of a communication speed. A communication device for transmitting data to a terminal device via a base station. The communication device is provided with: a response signal receiving unit for receiving a confirmation response from the terminal device; a buffer state estimation unit for calculating a wireless communication speed between the base station and the terminal device, calculating the amount of data retained in a transmission buffer of the base station as the retained amount of data, and predicting a change of the retained amount of data on the basis of the wireless communication speed, the retained amount of data and the received time of the confirmation response; a transmission time calculation unit for calculating a time at which new data is transmitted to the terminal device as an additional transmission time on the basis of the change predicted by the buffer state estimation unit; and a new data transmission unit for executing transmission of new data to the terminal device at a prescribed transmission rate on condition that at least the additional transmission time has elapsed.

Description

Communication apparatus, communication system, communication method and program

The present invention is based on the priority claim of Japanese Patent Application: Japanese Patent Application No. 2018-010571 (filed on January 25, 2018), the entire contents of the application being incorporated herein by reference. It shall be.
The present invention relates to a communication apparatus, a communication system, a communication method, and a program.

In recent years, traffic of mobile networks has increased due to the spread of smartphones and the like. Carrier aggregation (CA) introduced from Long Term Evolution (LTE) -Advanced is one of the techniques to cope with traffic increase. CA is a technology for realizing high-speed mobile communication as compared to the case of a single CC by simultaneously and simultaneously using a plurality of frequency lines called component carriers (CCs).

However, in communication using CA technology, the communication performance may not be maximized. This is because the communication device on the Internet side that controls the transport layer independently of the data link layer of the base station can not grasp the situation of the base station.

For example, TCP (Transmission Control Protocol) is known as a transport layer communication protocol that is standardly used in 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, there may be a mismatch 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 transmitting data to the terminal, the base station stores data to be transmitted 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 becomes temporarily empty, the base station has to stop transmission. However, it is not possible to grasp the situation where the transmission buffer of the base station is temporarily empty. Therefore, the communication apparatus on the Internet side can not complete data transmission to the base station. As a result, the wireless resources transmitted from the communication apparatus on the Internet side are wasted. Therefore, if the transmission buffer of the base station becomes empty during data transmission from the communication apparatus 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 address such problems, there are techniques for controlling the transport layer that improve end-to-end throughput.

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

JP, 2012-095190, A International Publication No. 2016/023935

Each disclosure of the above prior art documents is incorporated herein by reference. The following analysis is done by the present inventors.

In the technology disclosed in the above-mentioned patent documents, 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 can not solve the problem that the transmission buffer of the base station becomes empty. The reason is that, with this technology, it may not be possible to additionally transmit data at an appropriate timing. The above problems will be described in detail below.

In a general communication standard, the occurrence of an error in the communication process is inevitable. Therefore, in a general communication standard, a transmission error detection method and a retransmission control method are defined.

For example, in a general communication standard, a method of detecting an error when transmission failure occurs in a lower layer is defined. Further, in a general communication standard, when retransmission occurs, a method is defined to control retransmission by preventing completion of upper layer communication until retransmission success. Furthermore, in a general communication standard, when retransmission occurs in the lower layer, a method is also defined in which a subsequent packet waits until retransmission is completed to control retransmission.

Hereinafter, with reference to FIG. 2, an example will be described in which 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.

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 apparatus.

The base station 103 is 3GPP Rel. With 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, Or 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 an RLC layer of the base station 103.

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

Similarly, the terminal device communication unit 121, which is a communication unit of the terminal device, performs 3GPP Rel. With 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 apparatus.

Although two MAC layers ( terminal MAC layers 1213 a and 1213 b) of the terminal device are shown in FIG. 2, this is not intended to limit the number of MAC layers of the terminal device to two. Similarly, in FIG. 2, two physical layers (terminal physical layers 1214 a and 1214 b) of the terminal device are shown, but this does not mean that the number of physical layers of the terminal device is limited to two. In the following description, when it is not necessary to distinguish between the MAC layers of the terminal devices, they will be denoted as the terminal MAC layer 1213. Similarly, in the following description, the physical layer of the terminal device is described as a terminal physical layer 1214 if it is not necessary to distinguish 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. Also, the RLC layer (terminal RLC layer 1212) of the terminal apparatus is connected to at least one MAC layer (terminal MAC layer 1213).

When the base station MAC layer 1033 completes transmitting data to the terminal MAC layer 1213, the terminal MAC layer 1213 transmits data of transmission completion 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. Thereafter, the terminal RLC layer 1212 notifies the base station RLC layer 1032 that the data has been received normally.

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

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

In addition, since TCP congestion control has a function to limit the amount of unacknowledged data during transmission to the upper limit, the transmitting device can add new data unless it receives a transmission completion notification (ACK) from the terminal transport layer 1210. Do not send Therefore, when a 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 apparatus receives the ACK packet.

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

As a result, a fault occurs between the terminal transport layer 1210 and the base station RLC layer 1032 of the terminal apparatus on the transmission side. If a fault occurs between the terminal transport layer 1210 of the transmitting terminal and the base station RLC layer 1032, the terminal transport layer 1210 of the transmitting terminal receives an ACK when an RLC retransmission occurs. I can not 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 has been proposed in which the base station 103 notifies the terminal device on the transmission side of the buffer status [Patent Document 2] implements a function that can notify the base station of the buffer status. In addition, it is necessary to implement a function capable of receiving the buffer status notified to the terminal device on the transmission side, and the problem can not be solved by the device alone. In addition, the cost for practical use also increases. Further, although the base station information can be notified to the transmitting side according to Patent Document 2, since the radio information is put on the ACK and notified, the transmitting device can not transmit new data until the ACK is received, and the problem can not be solved. When this state continues and the amount of data stored in the transmission buffer of the base station 103 becomes zero, the communication speed may be degraded because there is no data to be transmitted even if there is transmission capability in the wireless band. .

In the technique of Patent Document 1, the timing of additional transmission of data is determined using a change in the relationship between the TCP congestion window size in the communication apparatus and the reception window size notified by the terminal by the TCP ACK. As described above, retransmission in the RLC layer occurs suddenly upon an error of radio transmission. Therefore, the communication apparatus described in Patent Document 1 can not detect that the data in the buffer of the base station has decreased to 0 even when observing changes in the congestion window size and the reception window size. As a result, the communication device described in Patent Document 1 can not additionally transmit data, which may cause deterioration in communication speed.

Also, a method may be considered in which additional transmission processing of data is performed simply by the increase in communication delay. However, when such a method is used, the communication apparatus can not appropriately set the timing for starting the additional transmission process of data and the amount of data to be additionally transmitted.

If the amount of data for additional transmission becomes too small, communication speed degradation may occur due to the data in the base station buffer becoming zero. 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 increased 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 apparatus, a communication system, a communication method, and a program that contribute to preventing deterioration of communication speed.

According to a first aspect, a communication device is provided. The communication apparatus transmits data to a terminal apparatus via a base station.
The communication device includes a response signal receiving unit that receives a confirmation response from the terminal device.
Furthermore, the wireless communication speed between the base station and the terminal apparatus is calculated, and the amount of data staying in the transmission buffer of the base station is calculated as the amount of staying data, and the wireless communication rate, the amount of staying data, and A buffer status estimation unit is provided that predicts the fluctuation of the amount of stagnant data based on the acknowledgment response reception time.
Furthermore, 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.
Furthermore, the communication device includes a new data transmission unit that transmits the new data to the terminal device at a predetermined transmission rate on condition that at least the additional transmission time has passed.

According to a second aspect, 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 that stores data to be transmitted to the terminal device.
The communication apparatus transmits data to the terminal apparatus via the base station.
Furthermore, the communication device includes a response signal receiving unit that receives a confirmation response from the terminal device.
Furthermore, the communication apparatus calculates a wireless communication speed between the base station and the terminal apparatus, calculates an amount of data accumulated in a transmission buffer of the base station as an accumulated data amount, and calculates the wireless communication speed and the wireless communication speed A buffer status estimation unit is provided which predicts the fluctuation of the amount of stagnant data based on the amount of stagnant data and the reception time of the confirmation response.
Furthermore, 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.
Furthermore, the communication device includes a new data transmission unit that transmits the new data to the terminal device at a predetermined transmission rate on condition that at least the additional transmission time has passed.

According to a third aspect, a communication method is provided. The communication method includes the step of receiving a confirmation response from a terminal device.
Further, the communication method includes the step of calculating a wireless communication speed between the base station and the terminal device.
Furthermore, the communication method includes the step of calculating the amount of data staying in the transmission buffer of the base station as the amount of staying data.
Furthermore, the communication method includes the step of predicting a change in the amount of stagnant data based on the wireless communication speed, the amount of stagnant data, and the reception time of the acknowledgment.
Furthermore, the communication method includes the step of calculating, as an additional transmission time, a time at which new data is transmitted to the terminal device based on the fluctuation.
Further, the communication method includes the step of transmitting the new data to the terminal device at a predetermined transmission rate, at least when the additional transmission time has passed.
Note that the method is tied to a particular machine, a communication device that transmits data to the terminal via the base station.

According to a fourth aspect, a program is provided. The program is a program that is executed by a computer that controls a communication apparatus that transmits data to a terminal apparatus via a base station.
The program causes the computer to execute a process of receiving a confirmation response from the terminal device.
Further, the communication method causes the computer to execute a process of calculating a wireless communication speed between the base station and the terminal device.
Further, the communication method causes the computer to execute a process of calculating the amount of data staying in the transmission buffer of the base station as the amount of staying data.
The program causes the computer to execute a process of predicting a change 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.
The program causes the computer to execute a process of calculating, as an additional transmission time, a time to transmit new data to the terminal device based on the fluctuation.
The program causes the computer to execute the process of transmitting the new data to the terminal device at a predetermined transmission rate on condition that at least the additional transmission time has passed.
The program can be recorded on a computer readable storage medium. The storage medium can be non-transient such as a semiconductor memory, a hard disk, a magnetic recording medium, an optical recording medium, and the like. The invention can also be embodied as a computer program product.

According to each aspect, a communication device, a communication system, a communication method, and a program that contribute to preventing deterioration of communication speed are provided.

It is a figure for explaining an outline of one embodiment. It is a block diagram which shows an example of a protocol structural example. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram illustrating an example of an entire configuration of a wireless communication system according to a first embodiment. It is a block diagram which shows an example of the hardware constitutions of the communication apparatus 11 which concerns on 1st Embodiment. It is a block diagram which shows an example of the hardware constitutions of the terminal device 12 which concerns on 1st Embodiment. It is a block diagram showing an example of composition of communication apparatus 11 concerning a 1st embodiment. 5 is a block diagram showing an example of the configuration of a response signal receiving unit 111. FIG. It is a flowchart which shows an example of operation | movement of the communication apparatus 11 which concerns on 1st Embodiment. It is a figure which shows an example of process time. It is a block diagram showing an example of composition of communication apparatus 21 concerning a 2nd embodiment. It is a flowchart figure which shows an example of operation | movement of the communication apparatus 21 which concerns on 2nd Embodiment.

First, an outline of one embodiment will be described with reference to FIG. The reference symbols of the drawings appended to this summary are added for convenience to each element as an example for aiding understanding, and the description of the summary is not intended to be limiting in any way. Also, connection lines between blocks in each block diagram include both bidirectional and unidirectional directions. The unidirectional arrows schematically indicate the flow of main signals (data), and do not exclude bidirectionality. Furthermore, in the circuit diagram, block diagram, internal configuration diagram, connection diagram and the like shown in the present disclosure, input ports and output ports are respectively present at the input end and the output end of each connection line, although they are not explicitly shown. The same is true for the input / output interface.

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

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

The response signal receiving unit 2 receives a 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 being transmitted by the base station as the amount of stagnant data, and receives the wireless communication speed, the amount of stagnant data, and the acknowledgment. The fluctuation of the amount of staying data is predicted based on the time of day.

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

The new data transmission unit 5 transmits the new data to the terminal apparatus at a predetermined transmission rate on condition that at least the additional transmission time has passed.

That is, the communication device 1 determines the timing for transmitting new data after taking into consideration the amount of stagnated data of the base station, with the case that at least the additional transmission time has passed as a necessary condition. Therefore, the communication device 1 contributes to preventing the transmission buffer of the base station from becoming empty. As a result, the communication device 1 contributes to the prevention of impossibility of transmitting new data in the wireless layer. Therefore, the communication device 1 contributes to preventing the 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 illustrating an example of the entire configuration of the wireless communication system according to the first embodiment.

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

For example, the networks 101-1 and 101-2 are mobile networks. The terminal device 12-1 connects to the network 101-1 via the base station 103-1. The terminal device 12-2 connects to the network 101-2 via the base station 103-2. In the following description, the terminal devices 12-1 and 12-2 will be denoted as the terminal device 12 if it is not necessary to distinguish them. Further, in the following description, the base stations 103-1 and 103-2 will be referred to as a base station 103, if it is not necessary to distinguish them. Also, in the following description, the networks 101-1 to 101-n will be referred to as the network 101 if it is not necessary to distinguish them.

The terminal device 12 accesses the server 105 on the Internet 104 via the corresponding network 101 to perform data communication. The communication apparatus 11 of the present invention is not applied only to the terminal apparatus 12 using the LTE network, but 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 relay station. Hereinafter, for convenience of explanation, the terminal device 12 will be described by exemplifying the case of using the LTE network. However, this is not the meaning 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 apparatus 11 is installed on the connection between the network 101 and the Internet 104 on the communication path is taken as an example. Of course, the installation place of the communication device 11 is not limited to the connection portion of the mobile network and the Internet, and may be a device on another communication path other than the connection portion. For example, the communication device 11 may be installed in the server 105 on the communication path.

[Hardware configuration]
Next, hardware configurations of 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 apparatus 11 according to the first embodiment.

[Configuration of communication device]
The communication device 11 includes, for example, the configuration illustrated in FIG. For example, the communication device 11 includes a central processing unit (CPU) 81, a memory 82, an input / output interface 83, and a network interface card (NIC) 84 as communication means, which are mutually connected by an internal bus.

However, the configuration shown in FIG. 4 does not mean that the hardware configuration of the communication apparatus 11 is limited. The communication device 11 may include hardware (not shown), and may not have the input / output interface 83 as necessary. Further, the number of CPUs and the like included in the communication device 11 is not limited to the example illustrated in FIG. 4. For example, the communication device 11 may include a plurality of CPUs.

The memory 82 is a random access memory (RAM), a read only memory (ROM), or an auxiliary storage device (such as a hard disk).

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

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. Also, the program can be downloaded via a network or can be updated using a storage medium storing the program. Furthermore, the processing module may be realized by a semiconductor chip. That is, the communication device 11 is configured to include means for performing the function performed by the processing module with some hardware and / or software.

[Configuration of terminal device]
The terminal device 12 has, for example, the configuration illustrated in FIG. The terminal device 12 is configured to include an RF (Radio Frequency) circuit 94 including an antenna 95. The RF circuit 94 is a circuit for realizing wireless communication, and exchanges a wireless signal with the base station 103 through the antenna 95. Among the hardware included in the terminal device 12, the description of hardware common to the communication device 11 is omitted.

The hardware configuration of the base station 103 is apparent to those skilled in the art, and thus the description thereof is omitted.

Subsequently, processing configurations (processing modules) 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 the communication device 11, the terminal device 12, and the network 101. The terminal device 12 is configured to include a terminal device communication unit 121. The network 101 is configured to include a base station 103. The communication device 11 is configured to include 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 reception 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 a response signal from the terminal device 12.

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

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

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

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

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 Open Systems Interconnection (OSI) 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. Configured Note that FIG. 7 relates to the 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 111 of the response signal reception unit 111. Specifically, the buffer status estimation unit 112 calculates a time at which it is estimated that the amount of staying data of the base station 103 becomes less than or equal to a predetermined threshold as a buffer depletion time. After that, the buffer status estimation unit 112 transmits the calculated buffer depletion time to the transmission time calculation unit 113.

Also, the buffer status estimation unit 112 may connect to another layer (for example, the communication device application layer 1110) of the response signal reception unit 111 without limiting the connection to the communication device transport layer 1111. For example, the communication protocol based on UDP such as QUIC is because the acknowledgment signal is not transmitted to the communication device transport layer 1111 but transmitted to the communication device application layer 1110.

The transmission time calculation unit 113 calculates the additional transmission time based on the transmission delay between the own communication apparatus 11 and the terminal apparatus 12, the reception time of the acknowledgment, and the buffer depletion 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 a transmission rate of additional transmission (hereinafter, referred to as an additional transmission rate).

The new data transmission unit 114 transmits the 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 apparatus 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 apparatus 11 and the terminal apparatus 12 according to the present embodiment may be TCP or the like that transmits a confirmation response in the communication apparatus transport layer 1111. Of course, the communication protocol between the communication apparatus 11 and the terminal apparatus 12 according to the present embodiment is not limited to the protocol for transmitting the acknowledgment in the communication apparatus transport layer 1111, but corresponds to the protocol for transmitting the acknowledgment in other layers. You may

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

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

Then, the buffer status estimation unit 112 calculates the amount of staying data of 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 staying data of the base station 103 and the buffer exhaustion time. Then, the buffer status estimation unit 112 transmits the calculated buffer depletion time to the transmission time calculation unit 113.

For example, the buffer status estimation unit 112 may calculate the amount of staying data of the base station 103 based on the amount of transmission data transmitted by the own 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 value of the data amount 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 the terminal device 12 can receive.

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

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

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

Here, when the communication apparatus 11 does not transmit new data to the base station 103, the amount of staying 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 staying 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 stagnant 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. May be

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

Also, for example, the buffer status estimation unit 112 may calculate, as an approximate value of the wireless communication speed, a value calculated taking into consideration the status of carrier aggregation based on the TCP throughput within the latest predetermined time. When the LTE carrier aggregation technology is applied, the frequency of occurrence of radio communication speed deterioration increases. Therefore, the buffer status estimation unit 112 calculates, for the terminal apparatus 12 to which the carrier aggregation technique is applied, the TCP throughput of the latest predetermined time and the number of component carriers used by the terminal apparatus 12. Thus, 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 the approximate value of the wireless communication speed using 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 the approximate value of the wireless communication speed using different TCP throughputs for each component carrier number (for example, f (1) = 1.0, f (2) = 1.02, f (3) = 1.04 etc.).

Also, the buffer status estimation unit 112 uses the 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 occurrence of wireless communication speed deterioration increases. Therefore, the buffer status estimation unit 112 estimates the number of component carriers based on the frequency (the number of occurrences within a predetermined time) when the arrival interval of acknowledgments (for example, ACK signals) exceeds a certain threshold using this characteristic. May be

Thereafter, the transmission time calculation unit 113 calculates an additional transmission time (step S13). Specifically, the transmission time calculation unit 113 takes into consideration the time 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 (that is, the transmission delay). , Calculate additional sending 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 apparatus 11 and the terminal apparatus 12.

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

Also, 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 at which the communication device 11 transmits a packet is Ta, and the time at which the communication device 11 receives a packet is Tb. In that case, RTT is Tb-Ta. However, in the terminal device 12, processing time is required 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 time of Tx and Ty in a packet, the transmission time calculation unit 113 uses ((Tb-Ta)-(Ty-Tx)) to transmit transmission data as a response signal The time until arrival at the transmission buffer of the base station 103 from the unit 111 is calculated. Note that, 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 header of TCP.

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

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

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

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

Next, the process in which the transmission time calculation unit 113 determines the necessity of the additional transmission will be described in detail with further reference to FIG.

In the standard model of LTE, when a transmission error occurs between an arbitrary base station MAC layer 1033 and a terminal MAC layer 1213, an extension of an ACK reception interval of the terminal transport layer 1210 occurs. In the terminal transport layer 1210, when the terminal device 12 can not 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 can not receive the TCP ACK. However, the buffer status estimation unit 112 estimates that the amount of staying data in the transmission buffer of the base station 103 is decreasing successively. Therefore, the transmission time calculation unit 113 determines whether or not additional transmission is necessary.

Also, the buffer status estimation unit 112 may estimate the amount of stagnated data in the transmission buffer of the base station 103 using acknowledgments of other protocols instead of TCP ACK. For example, the buffer status estimation unit 112 may estimate the amount of stagnant data in the transmission buffer of the base station 103 using a response signal of Quick UDP Internet Connections (QUIC) and Message Queue Telemetry Transport (MQTT). 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, but may be transmitted to another layer (for example, an application layer). In the following, for convenience of explanation, the case of transmitting a response signal using TCP of the terminal transport layer 1210 will be described. However, this does not mean that the terminal device 12 according to the present embodiment is limited to the case of transmitting a response signal using TCP of the terminal transport layer 1210.

The transmission time calculation unit 113 measures an elapsed time after the response signal reception unit 111 receives the latest ACK. In addition, when a plurality of TCP sessions for the same terminal apparatus 12 simultaneously communicate with the communication apparatus transport layer 1111, the transmission time calculation unit 113 determines an elapsed time from the time when the latest ACK is received among the plurality of TCP sessions. Measure In addition, the transmission time calculation unit 113 may measure an elapsed time after the response signal reception unit 111 transmits the latest packet.

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

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

Further, for example, the transmission time calculation unit 113 may calculate the transmission rate by approximating the TCP throughput in the latest predetermined time or the TCP transmission rate in the latest predetermined time. Also, the transmission time calculation unit 113 may calculate the transmission rate using the maximum TCP throughput in the TCP session or the maximum TCP throughput in the most recent predetermined time.

Further, it is assumed that the communication apparatus 11 establishes a plurality of TCP sessions with the same terminal apparatus 12. In that case, the transmission time calculation unit 113 calculates the transmission rate using the maximum value of the TCP throughputs of a plurality of TCP sessions or the sum of the TCP throughputs of a plurality of TCP sessions within the most recent predetermined time. It is also good.

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

The transmission time calculation unit 113 calculates the transmission rate using, for example, the same calculation as that when the buffer status estimation unit 112 approximates the wireless communication speed. Thereafter, 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, there is a mechanism for suppressing the amount of unconfirmed data to a predetermined value even if the amount of data is successfully transmitted, for congestion control. Specifically, generally, in TCP, control is performed so that the amount of in-flight data does not exceed the congestion window (cwnd) size. Also, in general, in TCP, control is performed so as not to exceed the reception window (rwnd) size included in the header of the ACK packet returned from the reception side.

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

[effect]
As described above, the communication apparatus 11 according to the first embodiment is estimated based on the wireless communication characteristic of the base station 103 that the amount of staying data in the transmission buffer of the base station 103 becomes equal to or less than a predetermined threshold. Predict time (ie, buffer exhaustion time). Thereafter, the communication apparatus 11 transmits new data to the base station 103 via the new data transmission unit 114 before the amount of staying data in the transmission buffer of the base station 103 becomes equal to or less than a predetermined threshold (for example, becomes zero). Send additional. Thereby, the communication apparatus 11 according to the present embodiment can maintain the amount of staying data in the transmission buffer of the base station 103 as the amount of data larger than a predetermined threshold (for example, larger than zero). Thus, the communication device 11 contributes to the prevention of impossibility of transmitting new data in the wireless layer. As a result, the communication device 11 can prevent the deterioration of the communication performance.

Second Embodiment
Next, a second embodiment will be described in detail using the drawings. In the present embodiment, information on a base station is acquired from a base station, and the acquired information is used to predict a buffer depletion time. In the description of the present embodiment, the description of the parts overlapping with the above embodiment will be omitted. Furthermore, in the description of the present embodiment, the same components as those of the above-described embodiment are denoted 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.

[Configuration of communication device]
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 on 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 sets the upper limit value of the transmission buffer of the base station 103 (hereinafter also referred to as the upper limit value of the buffer size) and the amount of data staying in the transmission buffer of the base station 103 as base station information. It may be acquired as Also, for example, the base station information acquisition unit 215 acquires base station information with the wireless communication speed of the base station 103 and the terminal device 12 and the number of communication radio waves between the base station 103 and the terminal device 12 (carrier aggregation status). May be Then, the base station information acquisition unit 215 transmits the acquired base station information to the buffer status estimation unit 212.

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

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

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

[Operation of communication device]
FIG. 11 is a flowchart showing an example of the operation of the communication apparatus 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, from the base station 103, the base station information acquisition unit 215 sets the upper limit value of the transmission buffer (the 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, At least one piece of information is acquired among the number of communication radio waves (carrier aggregation status). 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 as communication information from the response signal reception unit 211 (step S22).

The buffer status estimation unit 212 calculates the amount of staying data of 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 uses the amount of stagnated data in the base station 103, and Calculate buffer exhaustion 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 staying data of the base station 103 and the buffer exhaustion time. You may calculate 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 hold the base station 103. The amount of data and buffer exhaustion time may be calculated.

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

The buffer status estimation unit 212 uses the base station information acquired from the base station information acquisition unit 215 to calculate the amount of stagnant data in the transmission buffer of the base station 103 and the wireless communication speed. For example, the buffer status estimation unit 212 uses at least one of the amount of staying 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 staying data in the transmission buffer of the base station 103 is calculated.

Also, 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 staying data in the transmission buffer of the base station 103 becomes less than or equal to a predetermined threshold (for example, becomes zero) after time T seconds from the reference time. In that case, the buffer status estimation unit 212 calculates the time after T seconds has elapsed since the reference time as the buffer depletion time. Then, the buffer status estimation unit 212 transmits the calculated buffer depletion time to the transmission time calculation unit 213.

Thereafter, the transmission time calculation unit 213 calculates the additional transmission time (step S24). Specifically, the transmission time calculation unit 213 takes into consideration the time until the additionally transmitted data arrives from the response signal reception unit 211 to the transmission buffer of the base station 103 (that is, the transmission delay), and determines the additional transmission time. calculate. Here, the transmission time calculation unit 213 may use the information notified from the base station 103 to calculate the additional transmission time. For example, the transmission time calculation unit 213 uses the round trip delay between the base station 103 and the terminal 12 or the one-way delay, or the additional transmission time using the time stamp described in the information notified from the base station 103. It may be calculated.

The transmission time calculation unit 213 measures an elapsed time from when the response signal reception unit 211 receives the latest ACK. Further, in the communication apparatus transport layer 1111, when a plurality of TCP sessions for the same terminal apparatus 12 simultaneously communicate, the transmission time calculation unit 213 is an elapsed time from the time when the latest ACK was received among the plurality of TCP sessions. Measure Further, the transmission time calculation unit 213 may measure an elapsed time from the time when the response signal reception unit 211 transmitted the latest packet.

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

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

For example, when the response signal reception unit 211 receives an ACK signal, the transmission time calculation unit 213 may start a timer and measure an elapsed time after starting the timer.

On the other hand, if the response signal receiving unit 211 receives a new ACK during timer activation (No branch of step S25) until 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 a transmission rate.

The transmission time calculation unit 213 calculates, for example, the wireless communication speed within the latest predetermined time as a transmission rate. Also, 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. Also, 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. May be

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

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

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 most recent TCP throughput for a predetermined time and the number of component carriers used by the terminal device 12. Thereafter, 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 the 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 data ignoring the transmission amount, transmission time, or communication rate restriction defined 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 contributes to the prevention of deterioration in communication performance as compared with the communication device 11 according to the first embodiment. The reason is that the communication apparatus 21 according to the second embodiment predicts the buffer exhaustion time based on the base station information acquired from the base station 103. Furthermore, the communication apparatus 21 according to the present embodiment obtains the base station information directly from the base station 103 and calculates the transmission rate, thereby calculating the difference between the wireless communication speed acquired from the base station 103 and the calculated transmission rate. Can be reduced. Therefore, the communication apparatus 21 according to the present embodiment can avoid transmitting data using an under or over transmission rate. As a result, the communication device 21 according to the present embodiment contributes to preventing the performance deterioration of the communication network. Furthermore, the communication device 21 according to the present embodiment contributes to avoiding transmission of an amount of data exceeding the capability of the transmission buffer of the base station 103.

Some or all of the above-described embodiments may be described as in the following forms, but is not limited thereto.

(Mode 1) As described in the communication device according to the first aspect.

(Mode 2) The buffer status estimation unit calculates a time at which the stagnant data is estimated to be equal to or less than a predetermined threshold as a buffer depletion time, and the transmission time calculation unit transmits between the own communication device and the terminal device Preferably, the communication apparatus according to Mode 1 calculates the additional transmission time based on the delay, the reception time, and the buffer depletion time.

(Mode 3) The buffer status estimation unit further calculates the amount of staying data by further using the amount of transmission data transmitted by the own communication device and the amount of reception data received by the terminal device acquired from the confirmation response signal. Preferably, the communication device according to aspect 1 or 2.

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

(Mode 5) The communication apparatus according to any one of modes 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 apparatus.

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

(Mode 7) The transmission time calculation unit determines that at least one of an elapsed time from the reception time of the latest response signal and an elapsed time from the latest data transmission time reaches a threshold set in advance. The communication apparatus according to any one of modes 1 to 6, preferably determining time as the additional transmission time.

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

(Mode 9) The communication system according to the second aspect is as described above.

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

(Mode 11) The communication method according to the third aspect is as described above.

(Mode 12) The method further includes the step of calculating the time when the stagnant data is estimated to be equal to or less than a predetermined threshold as the buffer depletion time, and in the step of calculating the additional transmission time, transmission between the own communication device and the terminal device Preferably, the communication method according to Aspect 11, wherein the additional transmission time is calculated based on the delay, the reception time, and the buffer depletion time.

(Mode 13) A program according to the fourth aspect is as described above.

(Mode 14) The process of calculating the additional transmission time by causing the computer to further execute the process of calculating the buffer depletion time as the time when the stagnant data is estimated to be equal to or less than a predetermined threshold. The program according to preferably mode 13, wherein the additional transmission time is calculated based on a transmission delay between devices, the reception time, and the buffer depletion time.

The forms shown in the above-mentioned forms 9, 11 and 13 can be developed into the forms shown in the forms 3 to 8 similarly to the form shown in the form 1.

The disclosure of the above-mentioned patent documents is incorporated herein by reference. Within the scope of the entire disclosure of the present invention (including the scope of the claims), modifications and adjustments of the embodiment are possible based on the fundamental technical concept of the invention. Further, various combinations of various disclosed elements (including each element of each claim, each element of each embodiment, each element of each drawing, etc.) or selection (partially) within the scope of the entire disclosure of the present invention Possible) including deletion. That is, the present invention of course includes the entire disclosure including the scope of the claims, and various modifications and alterations that can be made by those skilled in the art according to the technical concept. In particular, with regard to the numerical ranges described herein, it should be understood that any numerical value or small range falling within the relevant range is specifically described even if it is not otherwise described. In the present invention, when algorithms, software, or flowcharts or automated process steps are shown, it is obvious that a computer is used, and it is also obvious that a computer is provided with a processor and a memory or storage. is there. Therefore, even in the absence of such a statement, it is understood that these elements are naturally described in the present application.

1, 11, 21 communication apparatus 2, 111, 211 response signal receiving unit 3, 112, 212 buffer status estimating unit 4, 113, 213 transmission time calculating unit 5, 114, 214 new data transmitting unit 12, 12-1, 12 -2 Terminal device 81, 91 CPU
82, 92 memory 83, 93 input / output 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 device 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 device application layer 1111 Communication device transport layer 1112 Communication device network layer 1113 Communication device MAC layer 1114 Communication device 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 (14)

1. A communication apparatus for transmitting data to a terminal apparatus via a base station, comprising:
   A response signal receiving unit that receives a confirmation response from the terminal device;
   The wireless communication speed between the base station and the terminal device is calculated, and the amount of data staying in the transmission buffer of the base station is calculated as the amount of staying data, and the wireless communication rate, the amount of staying data, and the confirmation response A buffer status estimation unit that predicts the fluctuation of the amount of stagnant data based on the reception time of
   A transmission time calculation unit that calculates, as an additional transmission time, a time at which new data is transmitted to the terminal device based on the fluctuation predicted by the buffer status estimation unit;
   A new data transmission unit configured to transmit the new data to the terminal device at a predetermined transmission rate on condition that at least the additional transmission time has elapsed;
   A communication device comprising
2. The buffer status estimation unit calculates, as a buffer exhaustion time, a time when the amount of stagnant data is estimated to be equal to or less than a predetermined threshold value.
   The communication apparatus according to claim 1, wherein the transmission time calculation unit calculates the additional transmission time based on a transmission delay between the own communication apparatus and the terminal apparatus, the reception time, and the buffer depletion time. .
3. The buffer status estimation unit further calculates the amount of staying data by further using the amount of transmission data transmitted by the own communication device and the amount of reception data received by the terminal device acquired from the confirmation response. Or the communication device according to 2.
4. The buffer status estimation unit calculates the staying data amount based on at least one of an upper limit value of a reception window size of the terminal apparatus and an upper limit value of the staying data amount of the transmission buffer of the base station. The communication apparatus according to any one of claims 1 to 3.
5. The communication apparatus 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 own communication apparatus.
6. The communication apparatus 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.
7. The transmission time calculation unit is configured to calculate a 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 threshold set in advance. The communication apparatus according to any one of claims 1 to 6, wherein
8. The communication apparatus according to any one of claims 1 to 7, wherein the transmission time calculation unit calculates a transmission rate based on the wireless communication speed.
9. A terminal device including a terminal device communication unit connected to a network;
   A base station comprising a transmission buffer for storing data to be transmitted to the terminal device;
   A communication apparatus for transmitting data to the terminal apparatus via the base station, the base station, and the terminal apparatus
   A communication system including
   The communication device is
   A response signal receiving unit that receives a confirmation response from the terminal device;
   The wireless communication speed between the base station and the terminal device is calculated, and the amount of data staying in the transmission buffer of the base station is calculated as the amount of staying data, and the wireless communication rate, the amount of staying data, and the confirmation response A buffer status estimation unit that predicts the fluctuation of the amount of stagnant data based on the reception time of
   A transmission time calculation unit that calculates, as an additional transmission time, a time to transmit new data to the terminal device based on the fluctuation predicted by the buffer status estimation unit;
   A new data transmission unit configured to transmit the new data to the terminal device at a predetermined transmission rate on condition that at least the additional transmission time has elapsed;
   A communication system comprising
10. The buffer status estimation unit calculates a time at which the accumulated data amount is estimated to be equal to or less than a predetermined threshold as a buffer depletion time, and the transmission time calculation unit calculates a transmission delay between the own communication device and the terminal device; The communication system according to claim 9, wherein the additional transmission time is calculated based on the reception time and the buffer depletion time.
11. Receiving an acknowledgment from the terminal device;
    Calculating a wireless communication speed between a base station and the terminal device;
    Calculating the amount of data staying in the transmission buffer of the base station as the amount of staying data;
    Predicting the fluctuation of the amount of stagnant data based on the wireless communication speed, the amount of stagnant data, and the reception time of the confirmation response;
    Calculating, as an additional transmission time, a time at which new data is transmitted to the terminal device based on the fluctuation;
    Performing transmission of the new data to the terminal device at a predetermined transmission rate on condition that at least the additional transmission time has elapsed;
    Communication method including:
12. The method further includes the step of calculating, as a buffer depletion time, a time at which the accumulated data amount is estimated to be equal to or less than a predetermined threshold, and in the step of calculating the additional transmission time, The communication method according to claim 11, wherein the additional transmission time is calculated based on the reception time and the buffer depletion time.
13. A program that is executed by a computer that controls a communication apparatus that transmits data to a terminal apparatus via a base station,
    A process of receiving a confirmation response from the terminal device;
    A process of calculating a wireless communication speed between the base station and the terminal device;
    Calculating the amount of data staying in the transmission buffer of the base station as the amount of staying data;
    A process of predicting a change 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;
    A process of calculating, as an additional transmission time, a time of transmitting new data to the terminal device based on the fluctuation;
    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 passed;
    A program that causes the computer to execute.
14. In the processing of calculating the additional transmission time by further causing the computer to execute, as the buffer exhaustion time, the process of calculating the time when the accumulated data amount is estimated to be equal to or less than a predetermined threshold, the process between the own communication device and the terminal device The program according to claim 13, wherein the additional transmission time is calculated based on a transmission delay, the reception time, and the buffer depletion time.

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