JP2018007019A - Data flow rate control method, radio base station device, server device, relay device, communication system, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow overflow and underflow to a buffer of a radio base station to be avoided even if the radio base station changes a radio parameter related to radio resource allocation.SOLUTION: A data flow rate control method includes: a transmission quantity estimation step for estimating, when a radio parameter related to allocation of radio resources is changed, a quantity of data transmission transmitted and destined to a radio terminal from a buffer temporarily storing the data destined to the radio terminal in consideration of change in the radio parameter; and inflow rate control step for controlling a quantity of data inflow destined to the radio terminal to the buffer on the basis of an estimation value of the quantity of data transmission from the buffer to the radio terminal and the quantity of data accumulation destined to the radio terminal stored in the buffer.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a data flow rate control method, a radio base station apparatus, a server apparatus, a relay apparatus, a communication system, and a program.

  A sequence number (SN: Sequence Number) is assigned to a packet transmitted by TCP (Transmission Control Protocol), and the receiving side performs order control to send the received packet to an upper layer in the order of the sequence number (Non-Patent Document 1). ). Note that TCP is a layer 4 (transport layer) protocol in the OSI (Open Systems Interconnection) basic reference model.

  In TCP, an acknowledgment (ACK: Acknowledgment) is sent back to the transmitting side that the transmitted packet has been correctly accepted by the receiving side. A packet that has not been acknowledged within a certain period of time after the packet is transmitted is retransmitted (Non-Patent Document 1). This waiting time until retransmission is referred to as “Retransmission Time Out” (RTO).

  In TCP, congestion control is performed to control the amount of data per unit time transmitted by the transmission side in accordance with the congestion status of the network (Non-Patent Document 2). Specifically, a packet in a window called “congestion window” (CWND) provided on the transmission side is transmitted. The size of the congestion window (Congestion Window Size) basically increases when an acknowledgment of the transmitted packet is obtained, and decreases when a retransmission timeout occurs.

  In recent years, in order to cope with an increase in network traffic accompanying the spread of the Internet, the capacity of wired communication has been increased, such as communication using optical fibers.

  In addition, due to the increase in rich content and rich applications accompanying the increase in network capacity and the advancement of terminal devices, studies on congestion control methods have been actively proposed in order to increase the speed of each communication flow.

  In addition, with the spread of mobile terminals such as smartphones and tablets, the ratio of transmitting and / or receiving the network traffic by wireless communication is also increasing. Therefore, speeding up wireless communication is also important. For example, in 3GPP (Third Generation Partnership Project), standardization of LTE (Long Term Evolution) and LTE Advanced is in progress.

  Protocols defined by LTE and LTE Advanced correspond to protocols below layer 2 (data link layer) in the OSI basic reference model. Therefore, in a communication system including a wireless communication system such as LTE, as illustrated in FIG. 14, the wireless terminal 910 and the server device 930 use protocols such as TCP and higher than the layer 3 (network layer) in the OSI basic reference model. Use to communicate. On the other hand, the wireless terminal 910 and the wireless base station 920 communicate using a layer 2 or lower protocol (LTE or LTE Advanced). FIG. 14 is a diagram schematically illustrating a protocol stack of U-Plane (User-Plane) in a communication system using LTE. In the wireless section between the wireless terminal 910 and the wireless base station 920, layer 1 is PHY (Physical Layer), layer 2 is MAC (Media Access Control), RLC (Radio Link Control), It consists of PDCP (Packet Data Convergence Protocol: Packet Data Convergence Protocol). In C-Plane (Control Plane), RRC (Radio Resource Control) on PDCP performs channel assignment of a radio section, and call control and the like are performed by a radio terminal 910 and a core network node (for example, MME (Mobility Management). Entity) and SGSN (Serving GPRS (General Packet Radio Service) Support Node)) are performed by a NAS (Non-Access Stratum) protocol. GTP-U (GPRS Tunneling Protocol User plane) on UDP (User Datagram Protocol) on the core network side of the wireless base station 920 is a tunnel protocol for transmitting user data. A P-GW (Packet Data Network) (PDN) -Gateway (PDN) connected to a radio base station via an S-GW (Serving-Gateway) (not shown) of the core network and connected to a packet data network (for example, the Internet). The L2 interface between the 960 and the server device 930 may be Ethernet (registered trademark).

  FIG. 15 is a diagram schematically illustrating a communication system using LTE. As schematically shown in FIG. 15, the radio base station 920 and the server device 930 are connected via a communication line network 940 (for example, the Internet and an LTE core network (EPC: Evolved Packet Core)), and a radio terminal 910 and the wireless base station 920 are connected via a wireless interface 950.

  Thus, in a communication system including LTE, protocols and communication characteristics are different between the wireless terminal 910 and the wireless base station 920 (wireless section) and between the wireless base station 920 and the server device 930 (wired section). Different.

  In general, the wireless section has a larger band fluctuation (communication speed fluctuation) than the wired section. For this reason, the radio base station 920 includes a buffer 921 for temporarily storing data addressed to the radio terminal 910 for the purpose of absorbing the influence of band fluctuation in the radio section. The buffer 921 of the wireless base station 920 stores, for example, data addressed to the wireless terminal 910 that has arrived from the server device 930 until transmission at Layer 2 to the wireless terminal 910 is completed.

  However, the fluctuation range of the communication speed (throughput) of the wireless section is very wide, for example, several Kbps (Kilo bits per second) to several hundred Mbps (Mega bits per second).

  Therefore, it is necessary to control the data inflow amount from the server apparatus 930 to the buffer 921 of the radio base station 920 so as to match the data transmission amount from the buffer 921 to the radio terminal 910. This is because if such control is not performed, overflow (data overflow) or underflow (data depletion) of the buffer 921 may occur.

  For example, when an overflow of the buffer 921 occurs due to congestion, the data that could not enter the buffer 921 is discarded for each packet (packet loss). When the packet is discarded, retransmission is performed from the server apparatus 930 that is the transmission source of the packet by TCP. At the same time, the above-described congestion control is performed in TCP. That is, when a packet is lost due to congestion or the like, congestion is avoided by reducing the congestion window, which is the upper limit value of the amount of data that can be transmitted at one time. As a result, there is a problem that the congestion window is reduced and the communication speed on the communication line 940 between the server device 930 and the radio base station 920 is lowered.

  On the other hand, when an underflow occurs in the buffer 921 of the radio base station 920, data (packets) to be transmitted from the buffer 921 to the radio terminal 910 disappears, and the radio band 950 between the radio base station 920 and the radio terminal 910 is used. The problem of reduced efficiency occurs.

  In order to solve the above-described problem, the amount of data addressed to the wireless terminal 910 stored in the buffer 921 of the wireless base station 920 approaches a transmission data amount for a predetermined time based on the communication speed of the wireless terminal 910 in the wireless section. In addition, several techniques for controlling the amount of data flowing into the buffer 921 have been proposed.

  For example, in Patent Document 1, the control station that relays data addressed to a mobile station and the base station that temporarily stores the data transmitted from the control station in a buffer and transmits the data to the mobile station are used. A method for controlling a data inflow amount to a base station, wherein the data is transferred based on a transmission rate of a radio link between the base station and the mobile station and an amount of the data staying in the buffer. A step of determining a buffer retention scheduled time that remains in the buffer before being transmitted to a station, and a step of controlling a transmission amount of the data transmitted from the control station based on the determined buffer retention scheduled time. , A data inflow control method is disclosed. According to the method disclosed in Patent Document 1, the base station monitors the transmission rate (communication speed in the wireless section) of the wireless link between the base station and the mobile station. Then, the base station uses the current transmission rate obtained by monitoring and the amount of data destined for the mobile station staying in the buffer of the base station to calculate the amount of data destined for the mobile station staying in the buffer. Then, the amount of data inflow into the buffer necessary for setting the amount of transmission data for a predetermined time based on the transmission rate of the mobile station is calculated, and the control station is notified of information relating to the calculated amount of data inflow. The control station controls the transmission amount of the data addressed to the mobile station transmitted from the control station based on the information on the data inflow amount notified from the base station.

  Patent Document 2 discloses a technique related to a mobile communication system including a radio base station and a base station controller (PCF: Packet Control Function). The radio base station receives data rate information indicating an expected value of the downlink data rate estimated based on the reception state of the radio communication terminal from the radio communication terminal, and an average value of the data rate information for a certain period is preset. A threshold value indicating that the average value does not exceed the data rate threshold when it is determined that the average value does not exceed the data rate threshold. A notification is transmitted to the base station controller. When the base station control device receives the sub-threshold notification, the base station control device determines to reduce a communication band allocated to communication performed between the wireless communication terminal and a communication destination device of the wireless communication terminal, and determines The communication band is notified to the communication destination device.

  In mobile communication, radio resources such as a frequency band and transmission power available for communication are limited. For this reason, in order to realize high speed and large capacity, efficient use of radio resources is required.

  In mobile communication, management of radio resources is generally performed by a scheduler of a radio base station.

  In general, a scheduler of a radio base station assigns radio resources to each radio terminal or each bearer based on quality information of a radio channel periodically fed back from the radio terminal. Here, the bearer refers to a logical line set between a wireless terminal and a wireless base station, between a wireless terminal and a mobile core network, between a wireless base station and a mobile core network, and the like. . In LTE, a radio bearer (RB), a network bearer (Evolved Packet System (EPS) Bearer, an E-UTRAN (Evolved Terrestrial Radio Access) and so on. The EPS bearer is a bearer that transfers a user IP packet established between the PGW and the radio terminal for each radio terminal (UE: User Equipment). The E-RAB is a radio access bearer that is set between a radio base station (eNodeB) and a radio terminal (UE: User Equipment) in a radio access network (RAN: Radio Access Network). The S1 bearer is a bearer established between the radio base station (eNodeB) and the SGW. The S5 / S8 bearer is a bearer established between the SGW and the PGW.

  According to the method disclosed in Non-Patent Document 3, the scheduler of the radio base station is expected to have an instantaneous rate expected when allocating radio resources calculated from quality information of radio channels periodically fed back from radio terminals, Radio resources are allocated based on a radio resource allocation index (also referred to as “radio resource allocation priority”) calculated from two of the average rates calculated from the transmission history of the radio terminal.

  In the case of LTE, the scheduler of the radio base station is a resource block (RB: Resource Block) that is a minimum allocation unit of frequency blocks that can be allocated to each radio terminal or each bearer, or a resource block group (RB) composed of a plurality of RBs. An allocation index is calculated for each RBG (Resource Block Group).

  As the instantaneous rate used to calculate the allocation index, CQI (Channel Quality Indicator) included in CSI (Channel State information), which is quality information of the radio channel fed back from the radio terminal to the radio base station, is used.

  The radio base station is generally a TBS per RB (Transport Block Size) or a TBS per RBG that can be transmitted by MCS (Modulation and Coding Scheme) determined based on radio channel quality converted from CQI.

  The average rate is a value obtained by averaging the number of transmission bits for each TTI (Transmission Time Interval), which is the minimum time unit for radio resource allocation. For example, a value obtained by dividing the instantaneous rate by the average rate is used as a radio resource allocation index (allocation priority).

  In general, a scheduler of a radio base station allocates RBs in order from a radio terminal or bearer having a large allocation index. As a result, each wireless terminal is prioritized for allocation to RBs having relatively high instantaneous wireless channel quality over average wireless channel quality. For this reason, it can contribute to the improvement of radio capacity.

  Also, the average rate decreases when radio resources are not allocated. When the average rate decreases, the value obtained by dividing the instantaneous rate by the average rate (radio resource allocation index) increases, and the allocation probability at the next allocation opportunity of radio resources increases. As a result, even if the wireless terminal has a poor communication channel quality, an opportunity to allocate wireless resources comes around. For this reason, it can also contribute to the fairness of the allocation opportunity of a radio | wireless resource between radio | wireless terminals.

  In recent years, the breakdown of mobile data traffic has diversified. In addition to realizing high speed and large capacity, it is now possible to stably provide each application with good quality of experience (QoE). This is one of the important themes for the competitive strategy of telecommunications carriers. For this reason, a scheduler taking QoE into account has attracted attention.

  According to the method disclosed in Patent Document 3, the radio base station identifies the traffic type of a packet that has arrived from the mobile core network, and sets an allowable delay amount and a target transmission rate according to the identified traffic type. Then, the radio base station controls the allocation of radio resources to each packet so as to satisfy the permissible delay amount and the target transmission rate. For example, when the transmission rate of a specific communication measured at a radio base station is less than the target transmission rate specified by the traffic type of the communication, the priority of radio resource allocation for the communication is increased. .

  Also, according to the method disclosed in Patent Document 4, the radio base station manages a QoE function indicating a relation between radio resource allocation and QoE for each traffic type. The scheduler of the radio base station identifies the traffic type of each radio terminal, performs temporary allocation of radio resources to the radio terminal by the method disclosed in Non-Patent Document 1, etc., and calculates the QoE function based on the temporary allocation result. To calculate the QoE of each wireless terminal. Then, the scheduler of the radio base station, for the radio terminal that satisfies the required condition that the calculated QoE is defined for each traffic type, within a range where the radio terminal satisfies the predetermined condition, part of the temporarily allocated radio resources, The calculated QoE can be accommodated to wireless terminals that cannot satisfy the requirements defined for each traffic type. As a result, it is possible to improve the QoE of the wireless terminal that cannot satisfy the predetermined condition while satisfying the prescribed QoE for the wireless terminal that satisfies the required condition.

Japanese Patent No. 4176576 JP 2008-141258 A Japanese Patent No. 4335619 Japanese Patent No. 5011408

J. et al. Postel, “Transmission Control Protocol”, STD 7, RFC 793, Sept. 1981 M.M. Allman, V.M. Paxson, W.M. Stevens, “TCP Congestion Control”, RFC 2581, April 1999 Christian Wenger et al, “Fairness and Throughput Analysis for Generalized Proportional Fair Frequency Scheduling in OFDMA,” VTC 2005-Spring. 2005 IEEE 61st (Volume: 3) Omori et al., “Effects of frequency scheduling considering delay based on QoS in downlink spread OFDM broadband wireless access”, IEICE Technical Report RCS 2004-276 (January 2005)

  The analysis of related technology is given below.

  When the radio resource allocation priority for each radio terminal is changed, the amount of radio resources allocated to each radio terminal increases and decreases, and thus the throughput of the radio section of each radio terminal changes rapidly.

  At this time, the technique disclosed in Patent Document 1 or Patent Document 2 has a problem that the wireless base station scheduler is insufficient to cope with a sudden change in the communication speed in the wireless section. This point will be described with reference to FIGS. 16 and 17 are diagrams newly created by the inventor of the present application in order to explain the problem of the present invention.

  For example, the radio resource allocation priority is updated (increased) by the scheduler of the radio base station for radio terminals with low throughput in the current radio section and severe transmission completion within an allowable delay ((1 in FIG. 16). ) To (2)), when the allocation priority of a certain radio terminal becomes relatively high, the throughput of the radio section of the radio terminal increases rapidly due to an increase in allocated radio resources. For this reason, the amount of data transmitted from the buffer of the radio base station increases rapidly.

  At this time, in the technique disclosed in Patent Literature 1 or Patent Literature 2, information on the data inflow amount to the buffer of the radio base station based on the measured value or average value of the throughput of the radio section used for control is obtained. Since it is fed back to the control station (control device), it takes time for the control station (control device) to perform the control reflecting the rapid increase in the throughput of the wireless section. The amount of data flowing into the buffer of the radio base station does not increase until the control reflecting the rapid increase in the throughput of the radio section is started.

  For this reason, in the technology disclosed in Patent Document 1 or Patent Document 2, the amount of data flowing into the buffer of the wireless base station (data inflow amount) is the amount of data transmitted from the buffer of the wireless base station (data transmission). A time period during which the amount of data destined for the wireless terminal stored in the buffer decreases. That is, as shown in (2) of FIG. 16, as a result of increasing the allocation priority, the data storage amount of the buffer of the radio base station becomes smaller than the target size. When the state of (2) in FIG. 16 continues for a long time, buffer underflow (data depletion) occurs as shown in (3) of FIG. When a buffer underflow (data depletion) occurs, the amount of data necessary for completion of transmission within the allowable delay cannot be transmitted to the wireless terminal, and the QoE of the wireless terminal cannot be improved.

  Further, when the radio resources allocated to a radio terminal whose transmission completion within the allowable delay is severe, the throughput of the radio section is reduced due to a decrease in radio resources allocated to the other radio terminals. Decrease rapidly. Therefore, in the other wireless terminal, the amount of data transmitted from the buffer may decrease rapidly. In this case, with the technique disclosed in Patent Document 1 or Patent Document 2, it takes time for the control station (control device) to perform control reflecting the sudden decrease in the throughput of the wireless section. For this reason, the data amount (data inflow amount) flowing into the buffer of the radio base station becomes larger than the data amount (data transmission amount) transmitted from the buffer, and the other radio terminals stored in the buffer A time zone in which the amount of addressed data increases ((2) in FIG. 17) occurs. If this time period is long, a buffer overflow (data overflow of (3) in FIG. 17) occurs. When a buffer overflow (data overflow) occurs, data (packets) discarded without being able to enter the buffer (packet loss) is retransmitted by TCP, and the communication speed is reduced by congestion control. As a result, the QoE of the wireless terminal is reduced.

  Note that the above-described problem is not limited to the case where the allocation priority of radio resources for each radio terminal is changed by a scheduler or the like.

For example, considering the application status and wireless channel quality,
Transmission power allocated to a reference signal (RS: Reference Signal)
Parameters (RS-to-PDSCH Offset, P _A , P _B , ρ _B / ρ _A , δ _power-offset ) relating to transmission power allocated to the downlink data channel (PDSCH: Physical Downlink Shared Channel),
-Transmission mode (Transmission Mode),
-Antenna configuration actually used (Antenna Configuration),
A transmission beam formed by beam forming;
Carrier frequency used for wireless communication (Carrier Frequency) or parameters related to carrier frequency (E-UTRA (Evolved Universal Radio Access)) Operating Band, EARFCN (EUTRA Absorb Frequency) Wireless link quality and traffic load,
-Component carrier (Component Carrier) used in Carrier Aggregation (Carrier Aggregation),
-Wireless terminal category (UE (User Equipment) Category, DL (Down Link) Category, UL (Uplink) Category), RAT (Radio Access Technology), etc.
The same occurs when changing the radio parameters related to radio resource allocation.

  Even when a radio parameter related to radio resource allocation is changed, it is desired to realize a system that can optimize the amount of data flowing into the buffer of the radio base station and avoid overflow and underflow of the buffer (the present invention). Knowledge).

  The present invention has been made to solve such problems, and one of its purposes is that even when the radio base station changes the radio parameters related to radio resource allocation, the radio base station An object of the present invention is to provide a data flow rate control method, apparatus, communication system, and program capable of avoiding overflow and underflow to a buffer.

According to the first aspect of the present invention, when there is a change in radio parameters related to radio resource allocation, a radio base station that receives data addressed to a radio terminal temporarily stores the data from the buffer. A transmission amount estimation step for calculating an estimated value of the data transmission amount for the above in consideration of the change of the wireless parameter;
An inflow amount control step of controlling an inflow amount of data into the buffer based on an estimated value of the data transmission amount from the buffer and a data accumulation amount accumulated in the buffer; Provided.

  According to the second aspect of the present invention, the buffer that temporarily stores the data addressed to the wireless terminal transmitted from the transmission source, and the data stored in the buffer is addressed to the wireless terminal based on the allocation result of the wireless resource. When there is a change in a transmission function and a predetermined radio parameter related to the allocation of the radio resource, an estimated value of the data transmission amount from the buffer to the radio terminal is calculated in consideration of the change of the radio parameter Based on the transmission amount estimation unit to perform, the estimated value of the data transmission amount, and the data accumulation amount accumulated in the buffer, the data inflow amount destined to the wireless terminal from the transmission source to the buffer is calculated. A radio base station apparatus including an inflow amount control unit and an information notification unit that notifies the transmission source of the data inflow amount is provided.

  According to the third aspect of the present invention, based on the function of receiving data inflow information addressed to a wireless terminal calculated by the radio base station via a communication network and the data inflow information, the radio base station And an inflow amount control unit that controls the amount of data addressed to the wireless terminal to be transmitted to the server.

According to the fourth aspect of the present invention, the function is connected between the radio base station and the server apparatus, and relays data addressed to the radio terminal transmitted from the server apparatus to the radio base station;
The data inflow information addressed to the wireless terminal calculated by the wireless base station is received via the communication network, and the data addressed to the wireless terminal is transmitted to the wireless base station based on the data inflow information. And a data amount control unit for controlling the amount.

According to the 5th form of this invention, the communication system provided with the radio | wireless terminal, the radio base station, and the server apparatus is provided.
The radio base station temporarily stores data addressed to the radio terminal transmitted from the server device, and a function of transmitting data stored in the buffer to the radio terminal based on a radio resource allocation result; A transmission amount estimation for calculating an estimated value of a data transmission amount from the buffer to the wireless terminal in consideration of the change of the wireless parameter when there is a change in a predetermined wireless parameter related to the allocation of the wireless resource And an inflow amount control unit that calculates an inflow amount of data addressed to the wireless terminal from the server device to the buffer based on an estimated value of the data transmission amount and a data accumulation amount accumulated in the buffer And an information notification unit that notifies the server device of the data inflow amount.
The server device includes an inflow amount control unit that receives a data inflow amount transmitted from the radio base station and controls a data amount destined for the radio terminal to be transmitted to the radio base station based on the data inflow amount information. .

According to a sixth aspect of the present invention, there is provided a communication system including a wireless terminal, a wireless base station, a server device, and a relay device connected between the wireless base station and the server device. Is done.
The wireless base station temporarily stores data addressed to the wireless terminal transmitted from the server device via the relay device, and the wireless terminal stores the data stored in the buffer based on a radio resource allocation result. When there is a change in the function to send to and a predetermined radio parameter related to the allocation of the radio resource, the estimated value of the data transmission amount from the buffer to the radio terminal in consideration of the change of the radio parameter The amount of data inflow addressed to the wireless terminal from the transmission source to the buffer is calculated based on the transmission amount estimation unit that calculates the estimated value of the data transmission amount and the data accumulation amount accumulated in the buffer. An inflow amount control unit for calculating, and an information notification unit for notifying the relay device of the data inflow amount.
The relay device receives a data inflow amount information addressed to the wireless terminal calculated by the wireless base station, and relays data addressed to the wireless terminal transmitted from the server device to the wireless base station. A data amount control unit for controlling the amount of data addressed to the wireless terminal to be transmitted to the wireless base station based on the data inflow amount information.

According to the seventh aspect of the present invention, there is provided a buffer for temporarily storing data addressed to a radio terminal transmitted from a transmission source, and the data stored in the buffer is addressed to the radio terminal based on a radio resource allocation result. In the computer constituting the base station apparatus including the function to transmit to
When there is a change in a predetermined radio parameter related to the allocation of the radio resource, a process of calculating an estimated value of the amount of data transmitted from the buffer to the radio terminal in consideration of the change of the radio parameter;
Based on the estimated value of the data transmission amount and the data accumulation amount accumulated in the buffer, a process for calculating the data inflow amount addressed to the wireless terminal from the transmission source to the buffer;
A process of notifying the transmission source of the data inflow amount;
A program for executing is provided.

According to the eighth aspect of the present invention, the computer constituting the server device
A process of receiving data inflow information addressed to a wireless terminal calculated by a wireless base station via a communication network;
Based on the data inflow information, a process for controlling the amount of data addressed to the wireless terminal to be transmitted to the wireless base station;
A program for executing is provided.

According to the ninth aspect of the present invention, a relay device is configured that is connected between a radio base station and a server device and relays data addressed to a radio terminal transmitted from the server device to the radio base station. To the computer
A process of receiving data inflow information addressed to a wireless terminal calculated by a wireless base station via a communication network;
Based on the data inflow information, there is provided a program for executing a process for controlling a data amount addressed to the wireless terminal to be transmitted to the wireless base station.

  According to the present invention, a computer-readable recording medium (for example, an HDD (Hard Disk Drive), a CD (Compact Disc), a DVD (Digital Versatile Disc), or a semiconductor storage device that stores the seventh to ninth programs. Non-transitory computer ready recordable media).

  According to the present invention, even when the radio base station changes radio parameters related to radio resource allocation, it is possible to avoid buffer overflow and underflow.

It is a figure which illustrates an example of the composition of the communications system in a 1st embodiment of the present invention. It is a figure which illustrates typically an example of a function of a base transceiver station and a server apparatus in a 1st embodiment of the present invention. It is a flowchart explaining an example of the operation | movement procedure of the change detection part and transmission amount estimation part of the wireless base station in the 1st Embodiment of this invention. It is a flowchart explaining an example of the operation | movement procedure of the transmission amount estimation part of the wireless base station in the 1st Embodiment of this invention. It is a flowchart explaining an example of the operation | movement procedure of the inflow amount control part of the radio base station in the 1st Embodiment and 2nd Embodiment of this invention. (A), (B) is a flowchart explaining the process sequence of the inflow control part of the server apparatus in the 1st Embodiment and 2nd Embodiment of this invention. It is a flowchart explaining an example of the operation | movement procedure of the transmission amount estimation part of the wireless base station in the 2nd Embodiment of this invention. It is a figure which illustrates typically an example of the composition of the communications system in a 3rd embodiment of the present invention. It is a figure which illustrates an example of the function of the wireless base station and server apparatus in the 3rd Embodiment of this invention. It is a flowchart explaining an example of the operation | movement procedure of the transmission amount estimation part of the wireless base station in the 3rd Embodiment of this invention. It is a flowchart explaining an example of the operation | movement procedure of the transmission amount estimation part of the wireless base station in the 4th Embodiment of this invention. It is a figure which illustrates the structural example of the modification of the communication system in the 5th Embodiment of this invention. (A), (B), (C) is a figure which illustrates the structural example (mounting example to information processing apparatus) of the wireless base station and server apparatus transmission control apparatus in embodiment of this invention. It is a figure showing the protocol stack of the communication system using LTE. It is a figure showing the communication system using LTE. It is the figure created in order to demonstrate the subject of this invention. It is the figure created in order to demonstrate the subject of this invention.

  Next, embodiments of the present invention will be described in detail with reference to the drawings. Note that the reference numerals in the drawings including the present embodiment, which are referred to in the description of the embodiments of the present invention, are added to the respective elements for convenience as an example for facilitating understanding. It is not intended to be limiting.

<First Embodiment>
[Description of configuration / function]
FIG. 1 is a diagram schematically illustrating an example of a configuration of a communication system 1 according to the first exemplary embodiment of the present invention. Referring to FIG. 1, the communication system 1 includes a wireless terminal 10, a wireless base station 20, and a server device 30. For convenience of explanation, in FIG. 1, the communication system 1 is illustrated as a configuration including one wireless terminal 10, one wireless base station, 20 server devices, and 30. Note that the number of wireless terminals 10 may be any number. Similarly, the number of radio base stations 20 and the number of server devices 30 may be any number. The wireless terminal 10 and the wireless base station 20 are configured to communicate via the mobile access network 11.

  Further, the radio base station 20 and the server device 30 are configured to communicate via a communication line network 50 (NW: Network).

  The communication line network 50 includes at least a mobile core network 51 and an external network 52 such as the Internet. The mobile core network 51 is connected to the external network 52 via a gateway (not shown). In this specification, the mobile core network 51 and the external network 52 are collectively referred to as a communication line network 50.

  Although not particularly limited, in the first embodiment of the present invention, the mobile access network 11 and the mobile core network 51 are respectively connected to a mobile access network (EUTRAN: Evolved UMTS Terrestrial) in an LTE radio system (RAT: Radio Access Technology). Radio access network (Radio Access Network) and mobile core network (EPC: Evolved Packet Core) are assumed. However, a mobile access network and a mobile core network in wireless systems other than LTE, such as UTRAN, UMTS (Universal Mobile Telecommunications System), and GSM (Global System for Mobile communications) may be assumed. Alternatively, the mobile access network 11 and the mobile core network 51 may be separate wireless systems. For example, the mobile core network 51 is an EPC in an LTE wireless system, and the mobile access network 11 is a Wi-Fi (Wireless Fidelity: registered trademark of Wi-Fi Alliance), a wireless LAN (Local Area Network), or a WiMAX (Worldwide Interoperability). (Access), LoRaWAN (Long Range Wide Area Network: registered trademark of LoRa Alliance), MultiFire, and other wireless systems may be used. The same applies to other embodiments described later.

  The wireless terminal 10 is any of a mobile phone terminal, a personal computer, a PHS (Personal Handyphone System) terminal, a PDA (Personal Data Assistance, Personal Digital Assistant), a smartphone, a tablet terminal, a car navigation terminal, a game terminal, or the like. is there. The wireless terminal 10 includes a CPU (Central Processing Unit), a storage device (memory), a transceiver (transmitter and receiver), an input device (key buttons and a microphone), and an output device (display and speaker).

The wireless terminal 10 may be configured to realize the functions of the wireless terminal 10 by executing a program stored in a storage device (not illustrated) by a CPU (not illustrated). Although not particularly limited, examples of functions provided in the wireless terminal 10 include the following functions.
A function of communicating with the server device 30 via the radio base station 20
A function for executing various communication services provided by the server device 30.
A function of transmitting and / or receiving a radio signal between the radio base stations 20 connected to the radio terminal 10 (communication link (RRC (Radio Resource Control) Connection is established)).
Based on the measurement setting information received from the radio base station 20, CQI (Channel Quality Indicator), RSRP (Reference Signal Received Power) or RSRQ (Reference Signal Received QQ) which is a reception quality index of the reference signal transmitted by the radio base station 20 ) And the like, and report to the connected radio base station 20 (measurement report).

  Since each function provided in the wireless terminal 10 is a well-known matter for those skilled in the art, description of each component of the wireless terminal 10 is omitted.

  The radio base station 20 includes, for example, an information processing apparatus (not shown) and a transceiver (transmitter and receiver). The information processing apparatus includes a central processing unit (CPU: Central Processing Unit) (not shown) and a storage device (memory and hard disk drive (HDD: Hard Disk Drive)). The radio base station 20 may be configured to realize functions to be described later when the CPU executes a program stored in the storage device.

The server device 30 is a device that provides various communication services to the wireless terminal 10. Although not particularly limited, the server device 30 is, for example,
・ WWW (World Wide Web) server,
FTP (File Transfer Protocol) server,
・ Mail server,
·file server,
・ Database server,
・ Application server,
・ Streaming server,
DNS (Domain Name System) server,
・ Proxy server,
-It may be an edge server.

  The server device 30 includes an information processing device (not shown) and a communication interface. The information processing apparatus includes a central processing unit (CPU) (not shown) and a storage device (a memory and a hard disk drive (HDD)). The server device 30 may be configured to realize a function of providing various communication services to the wireless terminal 10 by causing the CPU to execute a program stored in a storage device (not shown).

  FIG. 2 is a diagram schematically illustrating an example of functions of the radio base station 20 and the server device 30 of the communication system 1 of FIG.

  Referring to FIG. 2, the radio base station 20 includes a basic function unit 201, a buffer 202, a communication control unit 203, a change detection unit 204, a transmission amount estimation unit 205, an inflow amount control unit 206, and an information notification. A unit 207 is provided. As described above, the operation of each functional unit described below is performed by the central processing unit (CPU), the transceiver (transmitter and receiver), and the storage device (memory and HDD) of the radio base station 20 operating in cooperation with each other. It is realized by.

In FIG. 2, a basic function unit 201 of the radio base station 20 has a function provided in a radio base station in a general radio communication system. Although not particularly limited, the basic function unit 201 includes, for example, the following functions.
A function of transmitting and / or receiving a radio signal between the radio terminals 10 connected to the radio base station 20 (communication link established).
A function for generating a reference signal used by the wireless terminal 10 to measure the channel quality with the wireless base station 20.
A function of storing transmission data addressed to each wireless terminal 10 arriving via the communication line network 50.
A function for acquiring and managing QCI (Quality of Service (Class of Service) Class Identifier) related to transmission data.
A function for holding CQI, RSRP, and RSRQ reported from the wireless terminal 10.
A function of managing the wireless section throughput history of the wireless terminal 10
A radio base station 20 such as a physical resource block (PRB) usage rate or the number of radio terminals 10 connected to the radio base station 20 (also referred to as “active UE number” (active radio terminal number)). A function that measures and manages measurable information. One physical resource block is formed of time / frequency resources having a size of 180 KHz (KiloHerz) (12 subcarriers at 15 KHz intervals) on the frequency axis and 1 ms on the time axis.

  In the radio base station 20, each of the functions provided in the basic function unit 201 is well known to those skilled in the art, and therefore further description thereof is omitted in this specification.

  In FIG. 2, the buffer 202 of the radio base station 20 has a function of temporarily storing and managing transmission data addressed to each radio terminal 10 that arrives from the server apparatus 30 side via the communication line network 50.

The communication control unit 203 of the radio base station 20 has a radio resource management function provided in the radio base station in a general radio communication system. Although not particularly limited, the communication control unit 203 includes, for example, the following functions.
An RRC (Radio Resource Control) function for controlling a wireless connection state between the wireless base station 20 and the wireless terminal 10.
A function of determining the transmission mode (Transmission Mode) of each wireless terminal 10.
A function of determining transmission power to be allocated to the physical downlink shared data channel (PDSCH: Physical Downlink Shared Channel) (shared data channel for transmitting downlink user data) of each wireless terminal 10.
A function for determining the antenna configuration of each wireless terminal 10.
A function for determining a carrier frequency used for communication of each wireless terminal 10.
A function for determining whether to apply carrier aggregation of each wireless terminal 10.
A function of determining a component carrier used for communication of each wireless terminal 10.
A function for calculating an allocation index for each wireless terminal 10.
A function for determining a frequency block to be allocated to each wireless terminal 10 based on the calculated allocation index.

  Note that the above-described functions of the communication control unit 203 are well known to those skilled in the art, and further description thereof is omitted.

  In this embodiment, the radio resource allocation index M (i, k) is calculated based on the following formula (1), for example. For example, the description in Non-Patent Document 4 is referred to for the mathematical formula (1).

In Equation (1),
I is the identification number of the wireless terminal 10,
K represents the identification number of the resource block.

  In Equation (1), the packet transmission delay can be considered in the first term on the right side. Further, in the second term, it can be considered whether or not it is a retransmission. Further, a desired signal-to-interference signal ratio SINR (Signal-to-Interference plus Noise power Ratio) can be considered in the third term.

・・・（１）

... (1)

In the above formula (1),
The first term α _Delay · M _Delay (i) on the right side is an allocation index that allows consideration of packet transmission delay. M _Delay (i) is given by, for example, the following formula (2). M _Delay (i) is controlled based on the elapsed time since the packet was transmitted from the transmission source.

・・・（２）

... (2)

In the above formula (2),
T _req (i) is the allowable delay of the packet,
t (i) is the elapsed time since the packet was sent from the source,
T _thresh (i) is an arbitrary threshold,
Respectively.

In the present embodiment, the allowable delay T _req (i) of the packet is an allowable delay determined from the QCI related to transmission data addressed to the wireless terminal 10 acquired and managed by the basic function unit 201.

  In general, in order to stably provide an application with a good quality of experience (QoE), it is required to complete transmission of the packet within an allowable delay of the packet.

Therefore, for the packet transmitted from the transmission source, the remaining time until the allowable delay of the packet, that is, the time obtained by subtracting the elapsed time t (i) of the packet from the allowable delay T _req (i) of the packet: T _req ( i) When -t (i) is less than or equal to the threshold T _thresh (i), the value of M _Delay (i) is increased as a (> 0). When the value of T _req (i) −t (i) is larger than the threshold value T _thresh (i), the value of M _Delay (i) is set to 0.

In the above equation (1), alpha _Delay of the first term of the right side α _Delay · _{M Delay} (i) _is a weighting coefficient _{M Delay} (i).

Next, in the above formula (1), the second term α _Type · M _Type (i) on the right side is an allocation index that can consider whether or not retransmission is performed. M _Type (i) is given by, for example, the following formula (3).

・・・（３）

... (3)

In the above formula (3), N _retrans (i) represents the number of retransmissions. If it is a retransmission packet (when the number of retransmissions N _retrans (i) is 1 or more), M _Type (i) is 1, and if it is not a retransmission packet (when the number of retransmissions N _retrans (i) is 0), M _Type (i ) Is zero.

In the above equation (1), alpha _Type of the second term α _Type · _{M type} (i) _is the weighting factor of the _{M type} (i).

In this embodiment, the third term α _SINR · _{M SINR} of the equation (1) (i, k) of _M SINR (i, k), for example given by the following equation (4).

・・・（４）

... (4)

In the above formula (4),
CQI _inst (i, k) represents the instantaneous CQI (most recent CQI) of the resource block (RB) with the identification number k reported from the wireless terminal 10 with the identification number i.
SINR (·) represents a function for converting CQI to SINR.
SINR _ave (i, k) represents an average value of SINR for a predetermined period calculated by SINR (·).
SINR _thresh is an arbitrary threshold value.

SINR (·) outputs SINR (CQI _inst (i, k)) from instantaneous CQI _inst (i, k) for each resource block based on a CQI-SINR conversion table in which CQI and SINR are associated with each other. It may be.

In the above equation (1), alpha _SINR of the third term _{α SINR · M SINR (i,} k) _is a weighting coefficient _M SINR (i, k).

  In addition, the said numerical formula (2) respond | corresponds to the numerical formula (2) of a nonpatent literature 4, and the mathematical formulas (5) and (8) of the patent document 3, and the said mathematical formula (4) is the numerical formula (4) of a nonpatent literature 4. ), Which corresponds to Equation (4) in Patent Document 3.

In the above formula (4), when the threshold value SINR _thresh is set to a large value, when the ratio of the instantaneous SINR (CQI _inst (i, k)) to the average value: SINR _ave (i, k) is large, M _SINR SINR (CQI _inst (i, k)) is relatively high even if (i, k) increases and the average value: SINR _ave (i, k) is low (in a poor reception state). When good, M _SINR (i, k) increases. On the other hand, when the threshold SINR _thresh is set to a small value (SINR _ave (i, k)> SINR _thresh ), the higher the instantaneous SINR (CQI _inst (i, k)), the greater the increase in M _SINR (i, k). As the communication with the radio terminal 10 having a good reception state on average, the opportunity for radio resource allocation increases.

In FIG. 2, the change detection unit 204 of the radio base station 20 has a function of detecting a change in radio parameters related to radio resource allocation. Although not particularly limited, in the present embodiment, M _Delay (i) in the above equation (2) is used as a radio parameter related to radio resource allocation for which the change detection unit 204 detects a change.

In the above formula (2), the elapsed time t (i) from when the packet addressed to the wireless terminal 10 with the identification number i is transmitted from the transmission source is obtained by using the technique disclosed in Patent Document 3, for example. It may be a thing. In this case, the change detection unit 204 acquires the elapsed time t (i) in cooperation with the basic function unit 201 having a function of storing packets addressed to the wireless terminal 10 that arrives via the communication line network 50, You may make it detect the change of the value of _MDelay (i) of the said Numerical formula (2). Regarding the radio parameters M _Type (i) and M _SINR (i, k), the change detection unit 204 is based on the presence / absence of retransmission of the packet acquired by the basic function unit 201 and the received SINR information at the radio terminal 10. You may make it detect the change of each radio | wireless parameter.

  The transmission amount estimation unit 205 of the radio base station 20 transmits the radio terminal 10 transmitted from the buffer 202 after the change detection unit 204 detects a change in radio parameters related to radio resource allocation until a predetermined time has elapsed. It has a function of estimating the addressed data amount (referred to as “data transmission amount”).

  The data transmission amount addressed to the wireless terminal 10 from the buffer 202 estimated by the transmission amount estimation unit 205 of the wireless base station 20 is used by the inflow amount control unit 206.

  The inflow amount control unit 206 of the radio base station 20 transmits the data transmission amount to the wireless terminal 10 estimated by the transmission amount estimation unit 205, and the data amount to the wireless terminal 10 stored and managed by the buffer 202 (“data accumulation amount”). Is used to calculate the amount of data addressed to the wireless terminal 10 (referred to as “data inflow amount”) that flows into the buffer 202 from the server device 30 side. The data inflow amount to the buffer 202 calculated by the inflow amount control unit 206 and used for the wireless terminal 10 is used by the information notification unit 207.

  The information notification unit 207 of the radio base station 20 has a function of notifying the server device 30 of information related to the data inflow amount addressed to the wireless terminal 10 calculated by the inflow amount control unit 206.

  In the present embodiment, the information notification unit 207 of the radio base station 20 has a function capable of operating the header area and payload area of the layer 3 or higher packet in the OSI basic reference model.

  In the information notifying unit 207 of the radio base station 20, the information related to the data inflow amount of the radio terminal 10 is notified to the server device 30 by an IP (Internet Protocol) corresponding to the data addressed to the server device 30 transmitted by the radio terminal 10. ) This is performed by concatenating (concatenating and concatenating) the information with the packet. However, this information may be added to the header area of the IP packet. In this case, the information may be added to, for example, an unused field in the IP header.

  In addition, TCP (Transmission Control Protocol) used in an upper layer of the IP may be performed by concatenating the information with a TCP segment (referred to as “TCP packet”) corresponding to the IP packet. . Alternatively, this information may be added to the header area (TCP header: minimum 20 bytes) of the TCP packet. In this case, the information may be added to an unused field in the TCP header.

  Alternatively, instead of TCP, using UDP (User Datagram Protocol), the above notification is performed by concatenating the information with a UDP datagram corresponding to the IP packet (referred to as “UDP packet”). Also good. Further, the notification may be performed by adding the information to the header area (UDP header: 8 bytes) of the UDP packet.

  Alternatively, a new interface for notifying the information may be installed between the server device 30 and the radio base station 20, and the notification may be made via the interface.

  In FIG. 2, the server device 30 includes a basic function unit 301 and an inflow amount control unit 302. As described above, the operation of each functional unit described below is realized by the information processing device, the communication interface, and the storage device (memory, HDD, and the like) included in the server device 30 operating in cooperation with each other.

  As described above, the basic function unit 301 of the server device 30 functions to provide various communication services to the wireless terminal 10, and transmits and receives signals via the wireless base station 20 and the wireless terminal 10 through the communication line network. It has the function to receive. Note that functions known to those skilled in the art can be used as the functions of the basic function unit 301. Description of each function with which the basic function part 301 is provided is abbreviate | omitted.

  The inflow amount control unit 302 of the server device 30 is addressed to the wireless terminal 10 that transmits to the wireless base station 20 via the communication line network 50 based on the information related to the data inflow amount of the wireless terminal 10 notified from the wireless base station 20. Has a function of controlling the amount of data.

  In the present embodiment, the inflow amount control unit 302 of the server device 30 corresponds to, for example, an IP packet arriving from the wireless base station 20 via the communication line network 50 (data addressed to the server device 30 transmitted by the wireless terminal 10). ), The information regarding the data inflow amount addressed to the wireless terminal 10 to the buffer 202 of the wireless base station 20 may be acquired.

  The same applies to the case where a TCP packet or a UDP packet is used instead of an IP packet in the notification to the server device 30 of the information related to the data inflow addressed to the wireless terminal 10 to the buffer 202 of the wireless base station 20. is there. That is, the inflow amount control unit 302 of the server device 30 corresponds to the TCP packet or UDP packet (data transmitted to the server device 30 transmitted by the wireless terminal 10) that has arrived from the wireless base station 20 via the communication line network 50. ), The information regarding the data inflow amount of the wireless terminal 10 may be acquired.

  In addition, when a new interface for notifying the information is installed between the radio base station 20 and the server device 30, the following occurs.

  The radio base station 20 notifies the server device 30 of information relating to the data inflow amount addressed to the radio terminal 10 to the buffer 202 of the radio base station 20 via the new interface.

  The inflow amount control unit 302 of the server device 30 has a function of acquiring information via the interface. The server device 30 acquires information related to the data inflow amount addressed to the wireless terminal 10 to the buffer 202, which is notified via the interface.

[Description of operation]
Next, an operation procedure for optimizing the amount of data flowing into the buffer 202 of the radio base station 20 when the radio base station 20 changes radio parameters related to radio resource allocation will be described.

  FIG. 3 is a flowchart illustrating an example of operation procedures of the change detection unit 204 and the transmission amount estimation unit 205 of the radio base station 20 described with reference to FIG. Referring to FIG. 3, the change detection unit 204 of the radio base station 20 detects a radio parameter change related to radio resource allocation (step S100).

  When the change detection unit 204 detects a change in wireless parameter, the transmission amount estimation unit 205 transmits data from the buffer to all wireless terminals 10 that have established wireless links with the wireless base station 20, for example. An amount estimation process (step S101) is executed. In FIG. 3, for the sake of simple explanation, the data transmission amount for all the wireless terminals 10 (N units, N is an integer of 1 or more) that has established a wireless link with the wireless base station 20. Although the estimation process (step S101) is represented by a flowchart that is repeatedly executed as a subroutine, the process of the transmission amount estimation unit 205 (data transmission amount estimation process) is of course not limited to the implementation of the subroutine.

  FIG. 4 is a flowchart for explaining an example of an operation procedure of data transmission amount estimation processing in the transmission amount estimation unit 205 in step S101 of FIG.

  In the first embodiment, it is assumed that the data transmission amount addressed to the wireless terminal 10 with the identification number i from the buffer 202 and the radio resource allocation index M (i, k) have a positive correlation.

  First, the transmission amount estimation unit 205 obtains the data transmission amount D (i) addressed to the wireless terminal from the buffer 202 from the past history of the wireless terminal with the identification number i (step S102).

Next, the transmission amount estimation unit 205 calculates the data transmission amount D _out (i) addressed to the wireless terminal from the buffer 202 after the wireless parameter change related to the allocation of the wireless resource is performed for the wireless terminal 10 (step S103).

The transmission amount estimation unit 205 calculates the data transmission amount addressed to the wireless terminal 10 from the buffer 202 after changing the wireless parameter related to the wireless resource allocation to the wireless terminal 10 based on the following equation (5). Equation (5) indicates that the value of the elapsed time t (i) of the packet sent to the wireless terminal (identification number = i) transmitted from the transmission source is larger than {T _req (i) −T _thresh (i)}. To {T _req (i) −T _thresh (i)}, that is, the value of the radio parameter M _Delay (i) related to radio resource allocation of the radio terminal (identification number = i) is 0 This is the data transmission amount D _out (i) addressed to the wireless terminal (identification number = i) from the buffer 202 when changed to a.

・・・（５）

... (5)

In Formula (5),
D _out (i) on the left side is data addressed to the wireless terminal from the buffer 202 per time Δt (i) when the wireless parameter M _Delay (i) related to radio resource allocation in the wireless terminal with the identification number i is changed. This is the transmission amount [unit: bit].
D (i) on the right side is stored in the buffer 202 addressed to the wireless terminal at time t (i) derived from the past history (before the wireless parameter M _Delay (i) is changed) of the wireless terminal with the identification number i. Data inflow [unit: bit].
The coefficient β on the right side is a coefficient that can be arbitrarily set. Although not particularly limited, in this embodiment, β = 1.
Alpha _Delay of paragraph 1 alpha _Delay · a of the right side of the molecule is alpha _Delay of the equation (1), a is the in Equation (2), t (i) ≧ T req (i) -T thresh This is the value of M _Delay in the case of (i). The numerator and denominator α _Type and M _Type (i) are the above formula (1) and the above formula (3), and the numerator and denominator α _SINR and M _SINR (i) are the above formula (1) and the above formula (4). ).

In the above formula (5), in the above formula (1), when M _Delay (i) is changed to a, the value M (i, k) (numerator) and M _Delay (i) are 0. By multiplying the ratio of M (i, k) (denominator) by D (i) × {Δt (i) / t (i)}, M _Delay (i) is changed from 0 to a. The data transmission amount D _out (i) from the buffer 202 at time Δt (i) is obtained.

  FIG. 5 is a flowchart illustrating an operation procedure in which the inflow amount control unit 206 of the radio base station 20 controls the data inflow amount that flows into the buffer 202 of the radio base station 20 in the first embodiment.

After the radio base station 20 performs the operations shown in FIGS. 3 and 4, a radio link is established with the radio base station 20, and in the radio base station 20, a radio parameter M related to radio resource allocation is established. The operation illustrated in FIG. 5 is performed on the wireless terminal 10 having the identification number i in which the change of the _delay is detected. Hereinafter, the operation of the inflow amount control unit 206 of the radio base station 20 of FIG. 2 will be described with reference to FIG.

  The inflow amount control unit 206 of the wireless base station 20 uses the data transmission amount of the wireless terminal 10 calculated by the transmission amount estimation unit 205 and the data storage amount of the wireless terminal 10 managed by the buffer 202, and The amount of data flowing into the buffer 202 is calculated (step S201).

  The calculation formula of the data inflow amount into the buffer 202 for the wireless terminal 10 by the inflow amount control unit 206 is given by, for example, the following formula (6).

・・・（６）

... (6)

In the above formula (6),
D _in (i) on the left side is the amount of data flowing into the buffer 202 for the wireless terminal 10 with the identification number i.
B _target (i) on the right side is a target value of the data accumulation amount addressed to the wireless terminal 10 with the identification number i managed by the buffer 202 of the wireless base station 20.
B (i) is a data amount (data accumulation amount) addressed to the radio terminal 10 having the identification number i accumulated in the buffer 202 of the radio base station 20 at the current time t.
D _out (i) is a data transmission amount from the buffer 202 addressed to the wireless terminal 10 with the identification number i.
r (i) is the amount of data per unit time addressed to the wireless terminal 10 with the identification number i flowing into the buffer 202. Note that r (i) is expressed as r (i, t) when it changes depending on time, but is expressed as r (i) for simplicity.

In the above equation (6), the second term (·) on the right side represents the time Δt for the data storage amount B (i) addressed to the wireless terminal 10 in the buffer 202 at the current time t for the wireless terminal 10 with the identification number i. From the value obtained by adding the amount of data addressed to the wireless terminal 10 (the integrated value of r (i) of the time Δt from t to t + Δt) flowing into the buffer 202 during the period from the buffer 202 to the wireless terminal 10 A value obtained by subtracting the amount D _out (i) is, for example, the data accumulation amount addressed to the wireless terminal 10 in the buffer 202 at time t + Δt.

The value obtained by subtracting the data accumulation amount addressed to the wireless terminal 10 in the buffer 202 of the second term (·) from the target value B _target (i) of the first term on the right side of the equation (6) is the wireless terminal to the buffer 202. Data inflow amount D _in (i) addressed to 10 (the left side of the above equation (6)).

  The inflow amount control unit 206 of the radio base station 20 completes the operation after executing the process described in step S201 of FIG. 5 for all the radio terminals 10 that have established radio links with the radio base station 20. To do.

  In Equation (6), r (i), which is the data amount per unit time addressed to the wireless terminal 10 with the identification number i flowing into the buffer 202, may be a value observed most recently. In this case, the integral of the third term in parentheses on the right side of the equation (6) is given by r (i) × Δt.

  Alternatively, in the above equation (6), r (i) may be an average value of values observed at an arbitrary time before the current time. Alternatively, r (i) is data per unit time addressed to the wireless terminal 10 of the identification number i that has flowed into the buffer 202 using, for example, the least square method for a value observed at an arbitrary time before the current time. An approximate curve (linear equation) indicating the relationship between quantity and time is obtained, and may be a value after elapse of a predetermined time derived from the approximate curve (for example, linear interpolation), or after elapse of a predetermined time from the current time It is good also as an average value of the value up to. In this case, the integral of the third term in parentheses on the right side of the equation (6) is given by r (i) × Δt. Alternatively, r (i) may be the approximate curve that changes depending on time. In this case, the integration of the third term in parentheses on the right side of Equation (6) is calculated, for example, by numerical integration on the information processing apparatus of the radio base station 20.

  Alternatively, in the above equation (6), r (i) is the amount of data per unit time addressed to the wireless terminal 10 with the identification number i flowing into the buffer 202 from the value observed at an arbitrary time before the current time. A stochastic spread (stochastic diffusion) is obtained, and may be a value derived from the stochastic diffusion after a lapse of a predetermined time, or an average value of values from the current time to a lapse of a predetermined time. Also good. Alternatively, r (i) may be a function of the stochastic diffusion.

In the above formula (6), D _in (i) may be set to 0 when the calculation result on the right side is a value less than 0.

  FIG. 6A is a flowchart for explaining an example of an operation procedure in which the inflow amount control unit 302 of the server device 30 in FIG. 2 controls the data inflow amount addressed to the wireless terminal 10. When the server device 30 in FIG. 2 receives information on the amount of data flowing into the buffer 202 for the wireless terminal 10 with the identification number i from the wireless base station 20, the server device 30 receives The operation described in is performed.

  The inflow amount control unit 302 of the server device 30 uses the information related to the data inflow amount to the buffer 202 addressed to the wireless terminal 10 with the identification number i notified from the wireless base station 20 to the buffer 202 addressed to the wireless terminal 10. It is determined whether the data inflow amount is 0 or more (step S301).

  When the data inflow amount to the buffer 202 for the wireless terminal 10 is a positive value (YES branch in step S301), the inflow amount control unit 302 of the server device 30 uses the data in the buffer 202 for the wireless terminal 10 as the data. Data corresponding to the data inflow amount is added and transmitted to the radio base station 20 (step S302).

  For example, the inflow amount control unit 302 of the server device 30 increases the TCP congestion window until the number of TCP packets corresponding to the data inflow amount is transmitted, thereby performing additional transmission of data corresponding to the data inflow amount. It may be realized.

  The inflow amount control unit 302 of the server device 30 may obtain the number of TCP packets when additional data corresponding to the data inflow amount is transmitted using, for example, the following equation (7). .

・・・（７）

... (7)

In the above formula (7),
N _TCP is the number of TCP packets corresponding to the data inflow amount (D _in (i) _{in the} above formula (6)) addressed to the wireless terminal 10 (identification number = i) to the buffer 202 of the wireless base station 20. .

  MSS [unit: bit] is the maximum segment size (Maximum Segment Size) of TCP. MSS represents the maximum length of data that can be transferred in one segment in TCP (however, the header size of TCP is not included).

は、Ｃｅｉｌｉｎｇ（天井）関数であり、実数ｘを超えない最大の整数ｎを表す（Ｚは整数を表す）。

Is a Ceiling function and represents the maximum integer n that does not exceed the real number x (Z represents an integer).

  Referring to FIG. 6A, when the data inflow amount to the radio terminal 10 to the buffer 202 of the radio base station 20 in FIG. 2 is not a positive value (NO branch in step S301), the inflow of the server device 30 The quantity control unit 302 does not perform the process of step S302.

  The inflow amount control unit 302 of the server device 30 performs the above operation on each wireless terminal 10 that has received information regarding the data inflow amount from the inflow amount control unit 206 of the radio base station 20 to the buffer 202. Thereafter, the inflow rate control unit 302 of the server device 30 ends the operation illustrated in FIG.

  Alternatively, as shown in FIG. 6B, the inflow amount control unit 302 of the server device 30 has a case where the data inflow amount of the wireless terminal 10 to the buffer 202 of the wireless base station 20 in FIG. 2 is not a positive value. (NO branch in step S301), the inflow control unit 302 may suppress data transmission to the wireless terminal 10 (step S303).

In this case, the inflow amount control unit 302 of the server device 30 stops transmission to the wireless terminal 10 for a time (t _stop ) calculated from the following mathematical formula (8), thereby transmitting data to the wireless terminal 10. You may make it implement | achieve suppression.

・・・（８）

... (8)

In the above formula (8),
R _TCP (i) is the latest TCP throughput in the wireless terminal 10 with the identification number i. R _TCP (i) may be an average value of TCP throughput in the wireless terminal 10 with the identification number i observed at an arbitrary time before the current time.

Alternatively, in the above equation (8), R _TCP (i) is obtained by using the least square method from the TCP throughput in the wireless terminal 10 with the identification number i observed at an arbitrary time before the current time, and the wireless terminal 10 with the identification number i. A wireless terminal having an identification number i obtained after obtaining an approximate curve (linear equation) indicating the relationship between TCP throughput and time in, and derived from the approximate curve (or derived by linear interpolation) after elapse of a predetermined time from the current time 10 or the average value of the TCP throughput in the wireless terminal 10 with the identification number i from the current time to after a predetermined time has elapsed.

Alternatively, in the above equation (8), R _TCP (i) is the time of TCP throughput in the wireless terminal 10 with the identification number i from the TCP throughput in the wireless terminal 10 with the identification number i observed at an arbitrary time before the current time. The TCP throughput in the wireless terminal 10 with the identification number i after a predetermined time elapses from the current time, which is derived from the stochastic diffusion, is predicted as the stochastic spread (stochastic diffusion). The average value of the TCP throughput in the wireless terminal 10 with the identification number i after the elapse of a predetermined time from the time may be used.

  Further, the additional transmission of data corresponding to the data inflow amount of the wireless terminal 10 in step S302 of FIGS. 6A and 6B increases the expansion rate of the congestion window when a TCP ACK packet is received. May be realized.

  Note that the suppression of data transmission to the wireless terminal 10 in step S303 in FIG. 6B may be realized by lowering the expansion rate of the congestion window when a TCP ACK packet is received.

  As described above, according to the first embodiment of the present invention, the amount of data outflow to the buffer that is assumed after the radio parameter change related to radio resource allocation is calculated, By controlling the amount of data inflow, overflow and underflow of the buffer can be avoided. For this reason, it is possible to avoid a decrease in TCP throughput and improve a user's quality of experience (QoE).

<Second Embodiment>
Next, an exemplary second embodiment of the present invention will be described. The configuration of the system, the configuration of the radio base station, and the server device of the second embodiment are the same as those of the first embodiment described with reference to FIGS. 1 and 2, respectively. In the second embodiment, the processing operation of the transmission amount estimation unit 205 of the radio base station 20 of FIG. 2 is different from the processing operation of the transmission amount estimation unit 205 of the first embodiment described with reference to FIG. doing. Hereinafter, descriptions of the system configuration, the configuration of the radio base station 20, and the like will be omitted, and the operation of the transmission amount estimation unit 205 of the radio base station 20 will be mainly described.

[Description of operation]
An operation procedure for optimizing the amount of data flowing into the buffer 202 of the radio base station 20 when the radio base station 20 changes the radio parameter related to radio resource allocation will be described.

  FIG. 7 is a flowchart illustrating an example of an operation procedure in which the transmission amount estimation unit 205 of the wireless base station 20 illustrated in FIG. 2 estimates the data transmission amount of each wireless terminal 10 after the wireless parameters related to the allocation of wireless resources. It is. The radio base station 20 targets all radio terminals 10 that have established radio links with the radio base station 20 after the change detection unit 204 detects a radio parameter change related to radio resource allocation. The operation described in is performed. The operation of the transmission amount estimation unit 205 of the radio base station 20 will be described below with reference to FIGS.

  The transmission amount estimation unit 205 of the radio base station 20 includes a radio terminal 10 having a radio link established with the radio base station 20 as a “priority radio terminal” and other radio terminals 10 as “non-priority radio terminals”. (Step S111).

  The priority radio terminal is a radio terminal 10 that expects an increase in radio resource allocation based on radio parameters related to radio resource allocation changed in the communication control unit 203 of the radio base station 20.

In the second embodiment, as an example, the priority wireless terminal receives the wireless terminal 10 (identification) in which the value of the wireless parameter (M _Delay (i)) related to the allocation of the wireless resource calculated by Equation (2) is a. Number = i). That is, a time obtained by subtracting the packet elapsed time t (i) from the packet allowable delay T _req (i): T _req (i) −t (i) is equal to or less than the threshold value T _thresh (i). is there.

  Next, the transmission amount estimation unit 205 calculates, for each wireless terminal 10 classified as a priority wireless terminal, an expected value of the wireless section throughput after the wireless parameter change related to wireless resource allocation (step S112).

In order to calculate the expected value of the radio section throughput after the radio parameter (M _Delay (i)) relating to radio resource allocation to the radio terminal 10 is changed from 0 to a in the transmission amount estimation unit 205, Formula (9) is used.

  Here, the radio terminal 10 is a radio terminal classified as a priority radio terminal, and is a radio terminal that has not calculated an expected value of radio section throughput after radio parameter change related to radio resource allocation.

  Assume that the calculated expected value is used for the wireless terminal 10 that has already calculated the expected value of the wireless section throughput after changing the wireless parameter related to the allocation of the wireless resource as the priority wireless terminal.

  In Equation (9), it is assumed that the radio section throughput and the radio resource allocation index have a positive correlation, and the expected value of the radio section throughput after the radio parameter change related to radio resource allocation is calculated.

・・・（９）

... (9)

In the above formula (9),
E (i) on the left side is an expected value of the radio section throughput after the radio parameter change related to radio resource allocation in the priority radio terminal with the identification number i.
R (i) on the right side is the latest wireless section throughput in the priority wireless terminal with identification number i.
Α _Delay of the molecule is the above formula (1), a is the value of M _Delay (i) in the case of t (i) ≧ T _req (i) −T _thresh (i) in the above formula (2),
Α _Type and M _Type (i) of the numerator and denominator are the above formula (1), the above formula (3),
Α _SINR and M _SINR (i) of the numerator and denominator correspond to the above formula (1) and the above formula (4).
β is a coefficient that can be arbitrarily set, and is set to 1 in the present embodiment.

  Next, for each wireless terminal 10 classified as a priority wireless terminal, the transmission amount estimation unit 205 requests wireless resources that are wireless resources necessary for realizing the expected value of the wireless section throughput after the wireless parameter change calculated in step S112. Is calculated (step S113).

  The following formula (10) is a calculation formula for the transmission amount estimation unit 205 to obtain the required radio resource. In this embodiment, the radio resource is a resource block.

・・・（１０）

... (10)

In the above formula (10),
N _reqRB (i) is a radio resource (number of resource blocks) necessary to realize the expected value of the radio section throughput after the radio parameter change related to radio resource allocation in the priority radio terminal with the identification number i.
E (i) is an expected value of the radio section throughput after the radio parameter related to radio resource allocation in the priority radio terminal with the identification number i calculated using the above formula (9) is changed.
CQI (i) is the latest Wideband CQI in the priority wireless terminal with identification number i.
MCS (·) is a function for converting CQI into MCS (Modulation and Coding Scheme).
TBS (·) is a function for deriving TBS (Transport Block Size) from MCS and the number of resource blocks.
In the present embodiment, the number of resource blocks is calculated as 1 in the above formula (10).

  In LTE, data of layer 2 and higher is managed in units called transport blocks (7-byte header). The transport block is divided into resource blocks (RB) and accommodated in subframes (frame length 1 ms). At each TTI (Transmission Time Interval), one transport block is generated for each radio terminal to which an RB is assigned. The size of the transport block is determined from the number of physical resource blocks and MCS. In the above equation (10), the size of the transport block is calculated assuming that the number of resource blocks is 1. In LTE, in order to realize a high data rate, a short TTI such as 1 [ms] is employed. 1000 [TTI / sec] is used to convert a TTI in milliseconds (seconds) into seconds. The above equation (10) is based on the assumption that one resource block is required for one transport block transmission, by dividing the expected value of radio section throughput (communication speed: bps) by the size of the transport block (converted to bps). The number of radio resource blocks is obtained.

Subsequently, the transmission amount estimation unit 205 of the radio base station 20 uses the total radio resources that are radio resources of the radio base station 20 and the requested radio resource N _reqRB (i) calculated in step S113, and _performs non-priority. The remaining radio resources that are radio resources that can be allocated to the radio terminal are calculated (step S114).

  In the present embodiment, the total radio resource is the number of resource blocks determined from the system bandwidth. The following formula (11) is a calculation formula for the remaining radio resources in the present embodiment.

・・・（１１）

(11)

In the above formula (11),
N _RB is the number of resource blocks determined from the system bandwidth.
N _{restRB on the} left side is the number of resource blocks that can be allocated to non-priority wireless terminals.
N _priorUE is the number of priority wireless terminals.
MAX [•] is a function that returns the maximum value of the argument as a return value. If the value obtained by subtracting the sum of the number of resource blocks N _reqRB (i) that is the requested radio resource of each priority radio terminal from N _RB is negative, 0 is returned, and if the value is positive or 0, the value is returned. .

  Thereafter, the transmission amount estimation unit 205 of the radio base station 20 calculates the expected value of the radio section throughput after the radio parameter change related to radio resource allocation for each radio terminal 10 classified as a non-priority radio terminal (step S115).

  In the following formula (12), the transmission amount estimation unit 205 of the radio base station 20 calculates the expected value E (i) of the radio section throughput after the radio parameter change related to radio resource allocation in the non-priority radio terminal i. It is a mathematical formula for.

・・・（１２）

(12)

  In the above equation (12), for the TBS that is the number of transmission bits per minimum unit of the allocated radio resource, η (η is the expected value of the radio resource allocated to each non-priority radio terminal) Based on the resource block), an expected value E (i) of the wireless section throughput is derived.

はｆｌｏｏｒ（床）関数である（Ｚは整数）。

は、ｃｅｉｌｉｎｇ（天井）関数である。

の関係が成り立つ。

Is a floor function (Z is an integer).

Is the ceiling function.

The relationship holds.

TBS (MCS (CSI (i), floor (η))) corresponding to MCS (CSI (i), floor (η)) and TBS (MCS) corresponding to MCS (CSI (i), ceiling (η)) (CSI (i), ceiling (η))) is divided into internal ratios (ceiling (η) −η): {1− (ceiling (η) −η)}
The TBS corresponding to η is obtained by interpolation.

  In the above formula (12), η is calculated using the following formula (13).

・・・（１３）

... (13)

In Equation (13), N _npriorUE is the number of non-priority wireless terminals. N _restRB is derived based on Equation (11) above.

  Thereafter, the transmission amount estimation unit 205 of the radio base station 20 calculates the expected value E (i) of the radio section throughput after the radio parameter related to radio resource allocation calculated in step S112 or step S115 is changed. Is used to calculate the amount of data sent from the buffer 202 to each wireless terminal 10 (step S116).

  The following formula (14) is a formula used by the transmission amount estimation unit 205 of the radio base station 20 to calculate the data transmission amount from the buffer 202 to the radio terminal 10.

・・・（１４）

(14)

In the above formula (14),
D _out (i) on the left side is the amount of data transmitted from the buffer 202 to the wireless terminal with the identification number i. Also,
t is the current time, and Δt is a predetermined time that can be arbitrarily set. In this embodiment, Δt is the allowable delay T _thresh (i) used in Equation (2). The expected value E (i) of the throughput of the radio section after the radio parameter change for the priority radio terminal or the non-priority radio terminal is integrated over the period from time t to t + Δt.

  With the end of step S116, the transmission amount estimation unit 205 of the radio base station 20 ends the operation.

  In the above formula (9), R (i) may be an average value of the radio section throughput observed at an arbitrary time before the radio parameter change related to radio resource allocation in the priority radio terminal with the identification number i.

  Alternatively, in the above formula (9), R (i) uses the least square method from the radio section throughput observed at an arbitrary time before the radio parameter change related to the radio resource allocation in the priority radio terminal with the identification number i, An approximate curve (linear equation) indicating the relationship between the radio section throughput and time may be obtained, and the radio section throughput after a predetermined time elapses from the radio parameter change related to radio resource allocation derived from the approximate curve may be used. The average value of the wireless section throughput from the change of the wireless parameter relating to the assignment of the wireless resource to the end of a predetermined time may be used.

  Alternatively, in the above equation (9), R (i) is the radio section throughput and time from the radio section throughput observed at an arbitrary time before the radio parameter change related to radio resource allocation in the priority radio terminal with the identification number i. It may be a wireless section throughput after a predetermined time elapses after a radio parameter change related to radio resource allocation, derived from the stochastic spread, and after a radio parameter change related to radio resource allocation. It is good also as an average value of the radio section throughput until after predetermined time progress.

  In the above formula (10), CQI (i) may be an average value of Wideband CQIs observed at an arbitrary time before the radio parameter change related to radio resource allocation in the priority radio terminal of identification number i.

  Alternatively, in the above formula (10), CQI (i) is obtained by using the least square method from the Wideband CQI observed at an arbitrary time before the radio parameter change related to radio resource allocation in the priority radio terminal with the identification number i. An approximate curve (linear equation) showing the relationship between CQI and time may be obtained, and Wideband CQI derived from the approximate curve after a predetermined time has elapsed since the radio parameter change related to radio resource allocation may be obtained. Alternatively, in the above formula (10), CQI (i) may be an average value of Wideband CQIs after a predetermined time elapses after a radio parameter change related to radio resource allocation.

  Alternatively, in the above formula (10), CQI (i) is the probability of Wideband CQI and time from Wideband CQI observed at an arbitrary time before the radio parameter change related to radio resource allocation in the priority radio terminal with identification number i. It may be Wideband CQI after a predetermined time elapses after the radio parameter change related to radio resource allocation, which is derived from the stochastic spread, and a predetermined time elapses after the radio parameter change related to radio resource allocation. It is good also as an average value of Wideband CQI until after.

In the above formula (10), CQI (i) is a value obtained by averaging CQI _inst (i, k) of each resource block used in the above formula (4) for all resource blocks, instead of the Wideband CQI. It may be used. Alternatively, the CQI of an arbitrary resource block may be used from among the CQI _inst (i, k) of each resource block used in Equation (4).

  Also, in the above equation (10), instead of using MCS (•), the most recent MCS in the priority wireless terminal with identification number i may be used, and the radio related to radio resource allocation in the priority wireless terminal with identification number i. The average value of MCS observed at an arbitrary time before the parameter change may be used.

  Alternatively, in the above formula (10), instead of using MCS (•), the least square method is used from MCS observed at an arbitrary time before the radio parameter change related to radio resource allocation in the priority radio terminal with identification number i. Then, an approximate curve (linear equation) indicating the relationship between MCS and time may be obtained, and MCS after a predetermined time elapses after radio parameter change related to radio resource allocation derived from the approximate curve may be used.

  Alternatively, in the above formula (10), it may be an average value of MCS after a predetermined time elapses after a radio parameter change related to radio resource allocation.

  Alternatively, in the above equation (10), instead of using MCS (•), MCS and time are related from MCS observed at an arbitrary time before the radio parameter change related to radio resource allocation in the priority radio terminal with identification number i. The MCS may be a MCS after a predetermined time elapses after the radio parameter change related to radio resource allocation, which is derived from the stochastic spread, and the predetermined time elapses after the radio parameter change related to radio resource allocation. It is good also as an average value of MCS until after.

  Further, in the above formula (10), instead of using TBS (•), the latest TBS in the priority wireless terminal having the identification number i may be used.

  In the above formula (10), the average value of the TBS observed at an arbitrary time before the radio parameter change related to radio resource allocation in the priority radio terminal with the identification number i may be used.

  Alternatively, in the above equation (10), instead of using TBS (•), the least square method is used from the MCS observed at an arbitrary time before the radio parameter change related to the radio resource allocation in the priority radio terminal with the identification number i. Then, an approximate curve (linear equation) indicating the relationship between TBS and time is obtained, and MCS after a predetermined time elapses after the radio parameter change related to radio resource allocation derived from the approximate curve may be used.

  In the above formula (10), the average value of the TBS from when the radio parameter relating to radio resource allocation is changed to when a predetermined time has elapsed may be used. Alternatively, instead of using TBS (·), a TBS and a stochastic spread related to time are obtained from TBS observed at an arbitrary time before the radio parameter change related to radio resource allocation in the priority radio terminal of identification number i, It may be MCS after a predetermined time has elapsed since the radio parameter change related to radio resource allocation, derived from stochastic spreading, and the average value of TBS from the radio parameter change related to radio resource allocation until the predetermined time elapses It is good.

  Each of the above modifications may be applied in the above mathematical formula (12).

  In the above formula (9), β may be derived from the correlation between the radio interval throughput and the radio resource allocation index.

  In the second embodiment of the present invention, the operation procedure for controlling the data inflow amount that the inflow amount control unit 206 of the radio base station 20 causes the buffer 202 of the radio base station 20 to flow is described with reference to FIG. This is the same as in the first embodiment.

  The transmission amount estimation unit 205 of the radio base station 20 performs the operations of steps S111 to S116 shown in FIG. 7 and then performs the operation for each radio terminal 10 for which radio links are established with the radio base station 20 for each radio terminal 10. The operation described in 5 is executed.

  The inflow amount control unit 206 of the wireless base station 20 uses the data transmission amount of the wireless terminal 10 calculated by the transmission amount estimation unit 205 and the data storage amount of the wireless terminal 10 managed by the buffer 202 to the buffer 202. The amount of data inflow addressed to the wireless terminal 10 is calculated (step S201).

The inflow amount control unit 206 of the radio base station 20 uses, for example, the following formula (15) as a calculation formula for the data inflow amount D _in (i) addressed to the wireless terminal 10 to the buffer 202. In addition, since Formula (15) is the same as Formula (6) mentioned above, the description is abbreviate | omitted.

・・・（１５）

(15)

  The inflow amount control unit 206 of the radio base station 20 performs the process described in step S201 of FIG. 5 on all the radio terminals 10 that have established radio links with the radio base station 20, and then performs FIG. End the operation.

  In the above equation (15), r (i), which is the data amount per unit time addressed to the wireless terminal 10 with the identification number i flowing into the buffer 202, may be a value observed most recently, and before the current time. It is good also as an average value of the value observed at arbitrary time. Alternatively, r (i) uses the least square method from values observed at an arbitrary time before the current time, and the data amount and time per unit time addressed to the wireless terminal 10 with the identification number i that has flowed into the buffer 202. An approximate curve (linear equation) showing the above relationship may be obtained and may be a value after a predetermined time elapses derived from the approximate curve, or may be an average value of values from the current time until a predetermined time elapses. Alternatively, r (i) may be the approximate curve. Alternatively, r (i) is a stochastic spread (Stochastic) related to the amount of data per unit time and the time addressed to the wireless terminal 10 with the identification number i flowing into the buffer 202 from a value observed at an arbitrary time before the current time. (Diffusion) is obtained, and may be a value after a predetermined time elapses derived from the stochastic diffusion, or may be an average value of values from the current time until a predetermined time elapses. Alternatively, r (i) may be a function of the stochastic diffusion.

Similarly to the first embodiment, in the above formula (15), when the calculation result on the right side is a value less than 0, the data inflow amount D _in (i) may be set to 0.

  In the second embodiment, an operation procedure in which the inflow amount control unit 302 of the server device 30 in FIG. 2 controls the data inflow amount of the wireless terminal 10 is described with reference to FIGS. 6 (A) and 6 (B). This is the same as the first embodiment described. When the server device 30 receives information related to the data inflow amount of the wireless terminal 10 from the wireless base station 20, the server device 30 performs the operation illustrated in FIG. 6A or 6B for each wireless terminal 10. To do.

  First, the inflow amount control unit 302 of the server device 30 determines whether the data inflow amount of the wireless terminal 10 is 0 or more from the information related to the data inflow amount of the wireless terminal 10 notified from the wireless base station 20. (Step S301).

If the data inflow amount from the buffer 202 addressed to the wireless terminal 10 is a positive value (YES branch in step S301), the inflow amount control unit 302 of the server device 30 Are additionally transmitted (step S302). In the present embodiment, the inflow amount control unit 302 realizes additional transmission of data corresponding to the data inflow amount by expanding the TCP congestion window until the number of packets corresponding to the data inflow amount is transmitted. Shall. The number of TCP packets N _TCP is calculated by the following equation (16). Equation (16) is the same as Equation (7) described above.

・・・（１６）

... (16)

  On the other hand, when the data inflow amount from the buffer 202 addressed to the wireless terminal 10 is not a positive value (NO branch of step S301), the inflow amount control unit 302 of the server device 30 does not perform the process of step S302.

  The inflow amount control unit 302 performs the above operation on each wireless terminal 10 that has received the information related to the requested data inflow amount. Thereafter, the inflow amount control unit 302 ends the operation described in FIG. 6A or 6B.

In addition, as illustrated in FIG. 6B, when the data inflow amount of the wireless terminal 10 is not a positive value (step S301, NO branch), the inflow amount control unit 302 transmits data to the wireless terminal 10. It may be suppressed (step S303). In this case, the inflow amount control unit 302 of the server device 30 stops the transmission to the wireless terminal 10 by suppressing the transmission to the wireless terminal 10 by the time (t _stop ) calculated from Expression (17). It may be realized. In the following formula (17), R _TCP (i) is the latest TCP throughput in the wireless terminal 10 with the identification number i. Note that Equation (17) is the same as Equation (8) described above.

・・・（１７）

... (17)

In the equation (17), R _TCP (i) may be an average value of TCP throughput in the wireless terminal 10 with the identification number i observed at an arbitrary time before the current time. Alternatively, R _TCP (i) uses the least square method from the TCP throughput in the wireless terminal 10 with the identification number i observed at an arbitrary time before the current time, and uses the TCP throughput and the time in the wireless terminal 10 with the identification number i. An approximate curve (linear equation) indicating the relationship is obtained, derived from the approximate curve (derived by linear interpolation), and may be the TCP throughput in the wireless terminal 10 with the identification number i after a predetermined time has elapsed from the current time, The average value of the TCP throughput in the wireless terminal 10 with the identification number i from the current time until the elapse of a predetermined time may be used. Alternatively, R _TCP (i) is a probabilistic spread (probability) regarding the time of TCP throughput in the wireless terminal 10 with the identification number i from the TCP throughput in the wireless terminal 10 with the identification number i observed at an arbitrary time before the current time. The TCP throughput in the wireless terminal 10 with the identification number i after a predetermined time elapses from the current time, which is derived from the stochastic diffusion, may be calculated from the stochastic diffusion. The average value of the TCP throughput in the wireless terminal 10 with the identification number i may be used.

  Further, the additional transmission of data corresponding to the data inflow amount of the wireless terminal 10 in step S302 may be realized by increasing the expansion rate of the congestion window when the TCP ACK packet is received.

  Note that the suppression of data transmission to the wireless terminal 10 in step S303 may be realized by lowering the expansion rate of the congestion window when a TCP ACK packet is received.

  As described above, according to the second exemplary embodiment of the present invention, the expected value of the throughput of the radio section assumed after the radio parameter change related to radio resource allocation is calculated, and the expected value is calculated. By controlling the amount of data flowing into the buffer of the radio base station by using it, overflow and underflow of the buffer can be avoided, so that a decrease in TCP throughput can be avoided and the quality of experience (QoE) of the user can be improved.

  As mentioned above, although this invention was demonstrated with reference to the said embodiment, this invention is not limited to embodiment mentioned above. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

<Modification>
For example, in this embodiment, the function of the inflow amount control unit 206 of the radio base station 20 may be implemented in the inflow amount control unit 302 of the server device 30. In this case, the information notification unit 207 of the radio base station 20 includes information related to the data transmission amount of the radio terminal 10 calculated by the transmission amount estimation unit 205 of the radio base station 20 and the buffer 202 of the radio base station 20 that manages the information. Information related to the data storage amount of the wireless terminal 10 is notified to the server device 30.

  Further, the transmission amount estimation unit 205 of the radio base station 20 may be provided in the server device 30. In this case, the information notification unit 207 of the radio base station 20 includes the information related to the expected value of the radio section throughput after the radio parameter change related to the radio resource allocation calculated by the transmission amount estimation unit 205, and the buffer of the radio base station 20 The server device 30 is notified of information related to the data storage amount of the wireless terminal 10 managed by the server 202.

Further, in the present embodiment, the change detection unit 204 uses the communication control unit 203 to change the radio parameter using the value M _Delay (i) calculated by the above formula (2) as a radio parameter related to radio resource allocation. However, the present invention is not limited to this, and it is also possible to detect a change in radio parameters related to radio resource allocation.

For example,
-CQI, RSRP and RSRQ reported from the wireless terminal 10
・ Transmission power assigned to the reference signal,
-Transmit power allocated to downlink data channel,
・ Transmission mode,
The actual antenna configuration used,
・ Transmission beam formed by beam forming,
-Carrier frequency used for wireless communication,
-Radio link quality and traffic load related to the carrier frequency,
・ Component carrier used in carrier aggregation,
・ Wireless terminal category,
・ RAT
May be detected as a radio parameter related to radio resource allocation.

  In this case, the transmission amount estimation unit 205 calculates the data transmission amount of each wireless terminal 10 based on the wireless parameter to be changed.

  Furthermore, in the present embodiment, the change detection unit 204 may detect a case where a radio parameter related to radio resource allocation changes after a predetermined time has elapsed. In this case, the transmission amount estimation unit 205, the inflow amount control unit 206, the information notification unit 207, and the inflow amount control unit 302 operate before the radio parameters related to radio resource allocation are actually changed. The transmission amount is transmitted before the radio parameter related to radio resource allocation changes.

  In the present embodiment, the change detection unit 204 of the radio base station 20 may be provided in the radio terminal 10. For example, the change detection unit 204 uses CQI, RSRP, and RSRQ measured by the radio terminal 10 as radio parameters related to radio resource allocation, and states that the radio parameter is a predetermined value or less are radio parameters related to radio resource allocation. May be detected as a state of being changed.

  In this case, the change detection unit 204 provided in the radio terminal 10 notifies the radio base station 20 of a change in radio parameters related to radio resource allocation. The notification to the radio base station 20 is included in the existing information transmitted between the radio terminal 10 and the radio base station 20 such as an RRC message (for example, RRC Connection Setup Complete, RRC Connection Reconfiguration Complete, Measurement Report). You may be notified. Alternatively, a new information message for performing the notification may be defined and notified using the new information message.

  Modifications including the above-described modifications can be similarly performed in the following embodiments.

<Third Embodiment>
Next, an exemplary third embodiment of the present invention will be described in detail with reference to the drawings. In the third embodiment, a relay device is arranged between the radio base station and the server device, and the relay device acquires quality requirements related to the application in the radio terminal, and data flows into the buffer of the radio base station. Control the amount. The application in the wireless terminal includes, for example, an application program that is executed in the wireless terminal and affects the quality of experience (QoE) of the user. Although not particularly limited, the application program is, for example,
・ Web browser,
・ Mail program (mailer),
・ Location information display program,
・ Telephone program,
・ Short message service program,
・ Streaming service program,
・ Multimedia service program,
・ Gaming program,
・ Including social networking service programs.

[Description of configuration]
FIG. 8 is a diagram schematically showing a configuration of a communication system according to the third exemplary embodiment of the present invention. Referring to FIG. 8, the communication system 1A is different from the communication system 1 according to the first embodiment shown in FIG. 1 in that a wireless base station 21 and a server are used instead of the wireless base station 20 and the server device 30. A device 31 is provided. Furthermore, the communication system 1A newly includes a relay device 40 as compared with the communication system 1 according to the first embodiment. Hereinafter, in the third embodiment, description of the same elements as those in the first and second embodiments will be omitted as appropriate, and a configuration that is changed from the first and second embodiments will be mainly described.

  The relay device 40 is disposed between the server device 31 and the radio base station 21. In the example of FIG. 8, the relay device 40 is arranged in the external network 52. The relay device 40 relays data transmitted or received between the server device 31 and the radio base station 21. At that time, based on the data inflow information from the radio base station 21 and the like, the transmission of data to the radio base station 21 (and hence the data inflow addressed to the radio terminal 10 to the buffer of the radio base station 21) is controlled.

  The relay device 40 and the server device 31 are configured to communicate via an external network such as the Internet. Further, the relay device 40 and the radio base station 21 are configured to communicate via a communication line network.

  Similar to the first embodiment, the communication line network 50 includes an external network such as the Internet and a mobile core network. For convenience of explanation, in FIG. 8, the communication system 1 </ b> A is illustrated as a configuration including one each of the wireless terminal 10, the wireless base station 21, the server device 31, and the relay device 40. However, the number of wireless terminals 10 may be any number. Similarly, the number of radio base stations 21, the number of server devices 31, and the number of relay devices 40 may be any number.

  In FIG. 8, the radio base station 21 includes an information processing device and a transceiver (transmitter and receiver) (not shown) as in the radio base station 20 according to the first embodiment. The information processing apparatus includes a central processing unit (CPU) (not shown) and a storage device (memory and hard disk drive (HDD)). The radio base station 21 may be configured to realize functions to be described later when the CPU executes a program stored in the storage device.

  In FIG. 8, the server device 31 is a device that provides various communication services to the wireless terminal 10, similarly to the server device 30 according to the first embodiment. The server device 31 includes an information processing device (not shown) and a communication interface, similar to the server device 30 of the first and second embodiments. The information processing apparatus includes a central processing unit (CPU) (not shown) and a storage device (memory and hard disk drive (HDD)). The server device 31 may be configured to realize a function of providing various communication services to the wireless terminal 10 by the CPU executing a program stored in a storage device (not shown).

  The relay device 40 includes an information processing device and a communication interface (not shown). The information processing apparatus includes a central processing unit (CPU) (not shown) and a storage device (memory and hard disk drive (HDD)). The relay device 40 may be configured to realize functions to be described later when the CPU executes a program stored in a storage device (not shown).

  FIG. 9 is a diagram schematically illustrating functions of the communication system 1A according to the third embodiment illustrated in FIG. In the following, functions added and changed in the third embodiment will be described as compared with the first and second embodiments.

  As illustrated in FIG. 9, the server device 31 does not include the function of the inflow control unit 302 of the server device 30 of FIG. 2 but includes a basic function unit 301.

  The relay device 40 includes a basic function unit 401, an information acquisition unit 402, an information notification unit 403, and an inflow amount control unit 404.

  As described above, the operation of the following functional units is realized by the central processing unit (CPU), the information processing device, the communication interface, and the storage device (memory and HDD) included in the relay device 40 operating in cooperation with each other. Is done.

In FIG. 9, the basic function unit 401 of the relay device 40 is, for example,
A function of transmitting and / or receiving a signal via the server device 31 and an external network such as the Internet;
A function of transmitting and / or receiving signals via the radio base station 21 and the communication line network;
A function for measuring and managing the communication throughput (communication speed between the relay device 40 and the wireless terminal 10) between the relay device 40 and the wireless terminal 10 every predetermined time;
Etc.

  The information acquisition unit 402 of the relay device 40 has a function of acquiring predetermined information regarding an application in each wireless terminal 10.

In the present embodiment, the predetermined information related to the application is, for example, the quality requirement information of the application.
The request delay to satisfy the QoE of the application, and
-Required throughput to satisfy the QoE of the application,
including.

  In the relay device 40, information (quality requirement information) related to the application acquired by the information acquisition unit 402 is used by the information notification unit 403.

  In the relay device 40, the information information notification unit 403 notifies the radio base station 21 of information (quality requirement information) related to the application in each radio terminal 10 acquired by the information acquisition unit 402 via the basic function unit 401. Have

  Information on the application (quality requirement information) about the application in the wireless terminal 10 is notified to the wireless base station 21 by concatenating the information with an IP (Internet Protocol) packet corresponding to data addressed to the wireless terminal 10. It may be. In this case, the information may be added to the header area of the IP packet. Further, TCP (Transmission Control Protocol) used in an upper layer of the IP may be performed by concatenating the information with a TCP packet corresponding to the IP packet. Alternatively, this information may be added to the header area of the TCP packet. Alternatively, instead of TCP, UDP (User Datagram Protocol) may be used by concatenating the information with a UDP packet corresponding to the IP packet. Alternatively, this information may be added to the header area of the UDP packet. Alternatively, a new interface for notifying the information may be installed between the relay apparatus 40 and the radio base station 21 and notified via the interface.

  The inflow amount control unit 404 of the relay device 40 has the same function as the inflow amount control unit 302 of the server device 30 according to the first and second embodiments described with reference to FIG. That is, the inflow amount control unit 404 of the relay device 40 receives data inflow amount information addressed to the wireless terminal (identification number = i) to the buffer 202 from the inflow amount control unit 206 of the radio base station 21, and the data inflow amount is In the case of a positive value, data corresponding to the data inflow amount is additionally transmitted (step S302 in FIG. 6A). When the data inflow amount is 0 or a negative value, transmission of additional data is not performed or suppressed (step S303 in FIG. 6B). Further description of the inflow rate control unit 404 is omitted (refer to the description of the inflow rate control unit 302 of the server device 30 of the first and second embodiments).

  Compared with the radio base station 20 according to the first and second embodiments, the radio base station 21 uses a communication control unit 213 and a transmission amount estimation unit instead of the communication control unit 203 and the transmission amount estimation unit 205. 215 functions. Hereinafter, functions of the communication control unit 213 and the transmission amount estimation unit 215 in the radio base station 21 will be described.

  In the radio base station 21, the communication control unit 213 newly has a function of acquiring information (quality requirement information) regarding an application in the radio terminal 10 notified from the relay device 40.

  The communication control unit 213 of the radio base station 21 may be configured to have a function of DPI (Deep Packet Inspection), for example. The DPI of the communication control unit 213 acquires information related to the application running on the wireless terminal 10 from the IP packet corresponding to the data addressed to the wireless terminal 10 transmitted from the relay device 40. Note that DPI identifies the type of packet based on not only the packet header information but also the information on the payload (data portion), thereby identifying the application, behavior, and the like. get.

  At this time, the communication control unit 213 of the radio base station 21 may delete the information from the IP packet after acquiring information about the application in the radio terminal 10. Note that, in the case where a TCP packet or a UDP packet is used instead of an IP packet in the notification to the wireless base station 21 of the information related to the application in the wireless terminal 10, the communication control unit 213 of the wireless base station 21 similarly uses the DPI. The information regarding the application in the wireless terminal 10 may be acquired from the IP packet corresponding to the data addressed to the wireless terminal 10 transmitted from the relay device 40. At this time, the communication control unit 213 of the radio base station 21 may acquire the information related to the application in the radio terminal 10 and then delete the information related to the application from the packet.

  In addition, a new interface for notifying the information may be installed between the relay device 40 and the radio base station 21, and the information related to the application in the radio terminal 10 may be notified via the interface. In this case, the communication control unit 213 of the radio base station 21 has a function of acquiring information via the interface, and acquires information (quality requirement information) related to the application in the radio terminal 10 notified via the interface. It is good also as a structure.

  Further, the communication control unit 213 of the radio base station 21 uses the acquired information related to the application in the radio terminal 10 in the radio resource management function provided in the radio base station in a general radio communication system. This is different from the communication control unit 203 of the first and second embodiments described with reference to FIG.

In the present embodiment, as in the first and second embodiments, the radio resource allocation index M (i, k) is calculated based on the equations (1) to (4). However, in the present embodiment, the threshold value T _thresh (i) in Equation (2) is set as a request delay for satisfying the QoE of the application in the wireless terminal 10.

In addition, the value a of M _Delay (i) in the above formula (2) derives the correlation between the radio section throughput and the radio resource allocation index, and based on the correlation, the QoE of the application in the radio terminal 10 is calculated. A value necessary for achieving the required throughput for satisfaction may be set.

  The transmission amount estimation unit 215 of the radio base station 21 has a function of acquiring information related to the application in the radio terminal 10 notified from the relay device 40.

  The transmission amount estimation unit 215 of the radio base station 21 has a function of DPI (Deep Packet Inspection) and relates to an application in the radio terminal 10 from an IP packet corresponding to data addressed to the radio terminal 10 transmitted from the relay device 40. It is good also as a structure which acquires information.

  The transmission amount estimation unit 215 of the radio base station 21 may delete the information related to the application from the IP packet after acquiring the information related to the application in the radio terminal 10.

  Note that the transmission amount estimation unit 215 of the wireless base station 21 has a DPI function even when a TCP packet or a UDP packet is used instead of an IP packet in the notification to the wireless base station 21 of information related to the application in the wireless terminal 10. The information regarding the application in the wireless terminal 10 may be acquired from the IP packet corresponding to the data addressed to the wireless terminal 10 transmitted from the relay device 40. Further, the transmission amount estimation unit 215 may delete the information related to the application from the packet after acquiring the information related to the application in the wireless terminal 10.

  In addition, a new interface for notifying the information may be installed between the relay device 40 and the radio base station 21, and information related to the application in the radio terminal 10 may be notified via the interface. In this case, the transmission amount estimation unit 215 of the wireless base station 21 may have a function of acquiring information via the interface, and may acquire information related to the application in the wireless terminal 10 notified via the interface. .

  The transmission amount estimation unit 215 of the wireless base station 21 has a function of estimating the data transmission amount addressed to the wireless terminal 10 from the buffer 202 using the acquired information related to the application in the wireless terminal 10.

  The data transmission amount addressed to the wireless terminal 10 from the buffer 202 estimated by the transmission amount estimation unit 215 of the wireless base station 21 is used by the inflow amount control unit 206.

[Description of operation]
Next, an operation procedure for optimizing the amount of data flowing into the buffer 202 of the radio base station 21 when the radio base station 21 changes radio parameters related to radio resource allocation will be described.

  FIG. 10 illustrates an example of an operation procedure in which the transmission amount estimation unit 215 of the wireless base station 21 estimates the data transmission amount of each wireless terminal 10 in the third embodiment described with reference to FIGS. 8 and 9. It is a flowchart to explain. The radio base station 21 targets all the radio terminals 10 that have established radio links with the radio base station 20 after the change detection unit 204 detects the radio parameter change related to radio resource allocation. Execute the operation described in.

  Referring to FIG. 10, step S112 in FIG. 7 (calculation of expected wireless section throughput after changing wireless parameter for priority wireless terminal) is performed in step S401 (required throughput of application of priority wireless terminal is changed to wireless section after changing wireless parameter). Set as the expected throughput value). 10, step S111, step S113, step S114, step S115, and step S116 are the same as those in the second embodiment described with reference to FIG. Below, operation | movement of step S401 of FIG. 10 is demonstrated.

  The transmission amount estimation unit 215 of the radio base station 21 applies the application in the radio terminal 10 for each radio terminal 10 classified as the priority radio terminal after the processing of step S101 (classification of priority radio terminal and non-priority radio terminal) is completed. Is set as an expected value of the radio section throughput after the radio parameter change related to radio resource allocation (step S401). That is, in step S401, the transmission amount estimation unit 205 satisfies the QoE of the application in the wireless terminal 10 instead of calculating the right side of Equation (9) for each wireless terminal 10 classified as the priority wireless terminal. Is set as the expected value E (i) [bps] of the radio section throughput after the radio parameter change related to radio resource allocation.

  In the next step S113, the transmission amount estimation unit 205 of the radio base station 21 obtains a required radio resource, which is a radio resource necessary for realizing the expected value E (i) [bps] of the radio section throughput calculated in step S401. Calculation is performed using Equation (10) above.

The following steps are the same as those in the second embodiment. That is, in step S114, the transmission amount estimation unit 215 of the radio base station 21 calculates the remaining radio resources using the above formula (11). In the next step S115, the wireless section throughput expected value E (i) [bps] after the wireless parameter change for the non-priority wireless terminal is calculated using the above formula (12). In the last step S116, the transmission amount estimation unit 215 of the radio base station 21 calculates the expected value of the radio section throughput after the radio parameter related to radio resource allocation calculated in step S401 or step S115 is changed. For E (i), the data transmission amount D _out (i) from the buffer 202 for each wireless terminal 10 is calculated using the above equation (14).

  According to the third exemplary embodiment of the present invention, the amount of data inflow addressed to the radio terminal 10 to the buffer 202 of the radio base station 21 is controlled using the required throughput to satisfy the QoE of the application. Yes. For this reason, compared with the said 1st, 2nd embodiment, a user's experience quality (QoE) can be improved.

<Fourth Embodiment>
Next, an exemplary fourth embodiment of the present invention will be described. The configurations of the wireless terminal 10, the wireless base station 21, the relay device 40, and the server device 31 in the communication system according to the fourth exemplary embodiment of the present invention are the third configuration described with reference to FIGS. This is substantially the same as the embodiment. FIG. 11 is a flowchart illustrating an example of an operation procedure of the transmission amount estimation unit 215 of the radio base station 21 according to the fourth embodiment. In the fourth embodiment, for example, the transmission amount estimation unit 215 of the radio base station 21 of FIG. 8 performs the operation illustrated in FIG. 10 (a series of processes of steps S111, S401, and S113 to S116). The operation described in FIG. 11 may be executed.

  Referring to FIG. 11, step S401 in FIG. 10 is replaced with step S501, and steps S113 to S115 in FIG. 10 are replaced with steps S502 to S504. Hereinafter, the operations of the added steps S501 to S504 will be mainly described.

  The transmission amount estimation unit 215 of the radio base station 21 uses the radio terminal 10 for each radio terminal 10 classified as a non-priority radio terminal after the processing of step S101 (classification of priority radio terminals and non-priority radio terminals) is completed. The requested throughput for satisfying the QoE of the application is set as the expected value of the radio section throughput after the radio parameter change related to radio resource allocation (step S501). That is, in step S501, the transmission amount estimation unit 215 of the radio base station 21 sets, for each radio terminal 10 classified as a non-priority radio terminal, the required throughput for satisfying the QoE of the application in the radio terminal 10, It is set as the expected value E (i) [bps] of the wireless section throughput after the parameter change.

Next, the transmission amount estimation unit 215 of the radio base station 21 for each radio terminal 10 classified as a non-priority radio terminal, the expected value E (i) [bps of radio section throughput after the radio parameter change calculated in step S501. ] Is calculated using the above formula (10) (step S502). That is, in step S502, N _reqRB (i) in the above formula (10) is the expected value E (i) [bps of the radio section throughput after the radio parameter change related to radio resource allocation in the non-priority radio terminal with the identification number i. ] Is a radio resource necessary for realizing the above.

  In the next step S503, the transmission amount estimation unit 215 of the radio base station 21 calculates the remaining radio resources using the following formula (18).

・・・（１８）

... (18)

The above equation (18) is the radio resource allocation in the non-priority radio terminal as the radio resource necessary for realizing the expected value of the radio section throughput after the radio parameter change related to the radio resource allocation in the priority radio terminal in the above equation (11). Is replaced with the radio resources necessary for realizing the expected value of the radio section throughput after the radio parameter is changed, and the sum is replaced with the number of non-priority radio terminals from the number of priority radio terminals in the above equation (11). It is. That is, in the above formula (18), N _{restRB on} the left side is the number of resource blocks that can be allocated to the priority wireless terminal.
N _{RB on the} right side is the number of resource blocks determined from the system bandwidth.
N _reqRB (i) on the right side is the number of resource blocks that can be allocated to the non-priority wireless terminal having the identification number i obtained in step S502.
N _npriorUE is the number of non-priority wireless terminals.
MAX [•] is a function that returns the maximum value of the argument as a return value. If the value obtained by subtracting the sum of the number of resource blocks N _reqRB (i) that is the requested radio resource of each non-priority radio terminal from N _RB is negative, 0 is returned, and if the value is positive or 0, the value is return.

  Thereafter, the transmission amount estimation unit 215 of the radio base station 21 for each radio terminal 10 classified as the priority radio terminal expects the radio section throughput expected value E (i) [bps after radio parameter change related to radio resource allocation. ] Is calculated (step S504).

In step S503, the transmission amount estimation unit 215 of the radio base station 21 calculates the expected value E (i) of the radio section throughput after the radio parameter change related to the radio resource allocation of the priority radio terminal, by using the above formula (12 ) Is used. However, in the present embodiment, the following equation (19) is used for η in the equation (12) instead of the equation (13). As shown in equation (19), eta is a value obtained by dividing the number _{N PriorUE} priority the _{N RestRB} calculated wireless terminal using the above equation (18).

・・・（１９）

... (19)

In next step S116, the transmission amount estimation unit 215 of the radio base station 21 calculates the expected value of the radio section throughput after the radio parameter related to radio resource allocation calculated in step S501 or step S504 is changed. For E (i), the data transmission amount D _out (i) from the buffer 202 for each wireless terminal 10 is calculated using the above equation (14).

  According to the fourth exemplary embodiment of the present invention, when a radio terminal 10 that expects an increase in radio resource allocation occurs due to a radio parameter change related to radio resource allocation, Allocation of radio resources to the radio terminal 10 can be increased while ensuring the minimum guaranteed rate of the radio terminal 10.

  In the fourth exemplary embodiment of the present invention, the function of the relay device 40 may be in the server device 31. That is, the server device 31 may include an information acquisition unit 402, an information notification unit 403, and an inflow amount control unit 404. In this case, the relay device 40 is not an essential component.

<Fifth Embodiment>
Next, an exemplary fifth embodiment of the present invention will be described. In the third and fourth embodiments, in the communication system 1A shown in FIG. 8, the relay device 40 is arranged in the external network 52, but in the communication system 1B of the fifth embodiment, As shown in FIG. 12, the relay device 40 is disposed in the mobile core network 51. For example, the relay device 40 may be a P-GW (PDN (Packet Data Network) -Gateway) or S-GW (Serving-Gateway) arranged in the EPC.

  In this case, the information notification unit 403 of the relay device 40 notifies the wireless base station 21 of the information related to the application in the wireless terminal 10 using GTP (GPRS (General Packet Radio Service) corresponding to the data addressed to the wireless terminal 10. (Tunneling Protocol) packet may be performed by concatenating the information. Alternatively, the information may be added to the header area (GTP header) of the GTP packet.

  Alternatively, the information may be concatenated with the UDP packet corresponding to the GTP packet in the UDP used in the lower layer of the GTP. Alternatively, this information may be added to the header area of the UDP packet. Further, the IP may be performed by concatenating the information with the IP packet corresponding to the GTP packet by the IP used in the lower layer of the UDP. Alternatively, this information may be added to the header area of the IP packet.

  In the fifth embodiment, a new interface for notifying the information may be installed between the relay device 40 and the radio base station 21, and the notification may be made via the interface. In this case, the transmission amount estimation unit 215 of the radio base station 21 does not require the DPI function, and the application in the radio terminal 10 is obtained from various packets corresponding to the data addressed to the radio terminal 10 transmitted from the relay device 40. Get information about.

  A signal for transmitting information related to an application in the wireless terminal 10 transmitted from the relay device 40 arranged in the mobile core network 51 may be converted in the mobile core network 51 and transferred to the wireless base station 21.

  For example, when information related to an application in the wireless terminal 10 is notified by being concatenated with an IP packet corresponding to data addressed to the wireless terminal 10, the wireless terminal 10 concatenated with the IP packet in the mobile network 51. The information regarding the application may be transferred by concatenation to the GTP packet corresponding to the IP packet and transferred to the radio base station 21. Alternatively, information on the application may be transferred to the header area of the GTP packet and transferred to the radio base station 21. In addition, in UDP or IP used in the lower layer of the GTP, the packet may be transferred by concatenation to the packet and transferred to the radio base station 21, or may be transferred to the packet and transferred to the radio base station 21. May be forwarded to. Alternatively, a new interface for notifying the wireless base station 21 of the information may be installed in the mobile network, and the information may be transferred to the wireless base station 21 via the interface.

  Note that information related to the application in the wireless terminal 10 is transferred from the relay device 40 to the wireless base station 21 by means other than being concatenated with the IP packet corresponding to the data addressed to the wireless terminal 10 described in the present embodiment. Even when notified, a signal related to the information may be converted in the mobile core network and transferred to the radio base station 21 by the various methods described above.

  Note that the above conversion can be performed in any node installed in the mobile core network 51. The conversion can also be performed in the first and second embodiments.

  The first to fifth embodiments described above may be implemented independently, or may be implemented by appropriately combining a plurality of embodiments or parts (elements) of the embodiments. Good. For example, the combination of the radio base station of the first embodiment and the relay device 40 of the third or fourth embodiment, or the information acquisition unit 402 and / or the information notification unit of the relay device 40 of the third or fourth embodiment For example, 403 may be mounted on the server device of the first or second embodiment, and the embodiments or portions (elements) may be appropriately combined.

<Modification>
In addition to the possible combinations of the above-described embodiments, the above-described embodiments may be implemented in the following modifications.

  For example, the wireless terminal 10 provides information related to the application from the application layer to the lower RRC layer. The RRC layer processing unit of the radio terminal 10 uses information related to an application provided from an upper application layer (for example, information for calculating the amount of data that can be transmitted) as an RRC message (for example, RRC Connection Setup Complete, RRC). (Connection Reconfiguration Complete, Measurement Report). At this time, the information related to the application is transmitted in the same RRC message together with information (for example, RSRP, RSRQ) for calculating the wireless section throughput (for example, the amount of data that can be transmitted before a predetermined time elapses). Alternatively, it may be transmitted separately.

  The radio base station 20 (21) that has received the RRC message performs the above-described operation of the communication control unit based on the information related to the application included in the RRC message and the information for calculating the radio section throughput. You may do it.

  In addition (or), the above-described embodiment may be applied to a configuration including MEC (Mobile Edge Computing) arranged in or near the radio base station. That is, the operation of the above-described embodiment is performed in the communication system including the MEC server as the server device 30 (31) in the above-described embodiment, the wireless terminal 10, the wireless base station 20 (21), and the relay device 40. It may be. In this case, the relay device 40 is not an essential component. Alternatively, the relay device 40 may be virtually installed in the MEC server.

  In addition (or), the above-described embodiment may be applied to a configuration including a data center (DC: Data Center) including a function of a radio base station and a function of a mobile core network. That is, the operation of the above-described embodiment may be performed in a communication system including the DC as the wireless base station 21 in the above-described embodiment, the server device 31, the wireless terminal 10, and the relay device 40.

  The DC may be a core DC or a distributed DC. In this case, the relay device 40 is not an essential component. Alternatively, the relay device 40 may be virtually mounted on the DC.

  An example in which the functions of the radio base station 20 (21), the server device 30 (31), and the relay device 40 are implemented by a program will be described. For example, as schematically illustrated in FIG. 13A, the radio base station 20 (21) includes a transceiver 20-1, an information processing device 20-2, and a communication interface 20-3. The transmitter 20-11 of the transceiver 20-1 power-amplifies an RF (Radio Frequency) signal obtained by frequency-converting (up-converting) a baseband signal to be transmitted into a carrier band, and transmits the amplified signal from the antenna 20-13. The receiver 20-12 of the transceiver 20-1 amplifies the RF signal received by the antenna 20-13 with low noise and performs frequency conversion (down-conversion) to a baseband signal. The information processing apparatus 20-2 performs, for example, baseband signal processing, call processing, monitoring control, and the like. The information processing apparatus 20-2 modulates downlink packet data received from the mobile core network 51 side via the communication interface 20-3 into a baseband signal and transmits the baseband signal to the transmitter 20-11. Further, the information processing apparatus 20-2 demodulates the baseband signal received from the receiver 20-12 and transmits the demodulated signal to the mobile core network 51 via the communication interface 20-3. The information processing apparatus 20-2 includes a central processing unit (CPU: Central Processing Unit) 20-21 and a storage device 20-22. The storage device 20-22 includes, for example, a semiconductor memory and a hard disk drive (HDD). The storage device 20-22 stores a program executed by the CPU 20-21. The communication interface 20-3 communicates with the core network. Note that the storage device 20-22 may include the buffer 202 in FIG. The radio base station 20 (21) executes the program stored in the storage device 20-22 by the CPU 20-21, whereby the basic function unit 201, the communication control unit 203 (213) in FIG. 2 (FIG. 9), A part or all of the functions of the change detection unit 204, the transmission amount estimation unit 205 (215), the inflow amount control unit 206, and the information notification unit 207 may be realized.

  For example, as schematically shown in FIG. 13B, the server device 30 (31) includes a communication interface 30-1 that communicates with the external network 52, and an information processing device 30-2. The information processing device 30-2 includes a central processing unit (CPU) 30-21 and a storage device 30-22. The storage device 30-22 includes, for example, a semiconductor memory and a hard disk drive (HDD). The storage device 30-22 stores a program executed by the CPU 30-21. When the CPU 30-21 executes the program stored in the storage device 30-22, the server device 30 (31) executes the basic function unit 301 in FIG. 2 (FIG. 9) and the inflow amount control unit 302 in FIG. It may be configured to realize part or all of the functions.

  As shown in FIG. 13C, the relay device 40 includes an information processing device 40-1 and a communication interface 40-2. The information processing apparatus 40-1 includes a central processing unit (CPU) 40-11, a storage device 40-12 (memory and hard disk drive (HDD)), and the like. The storage device 40-12 stores a program executed by the CPU 40-11. The relay device 40 executes one of the functions of the basic function unit 401, the information acquisition unit 402, the information notification unit 403, and the inflow amount control unit 404 when the CPU 40-11 executes a program stored in the storage device 40-12. You may comprise so that a part or all may be implement | achieved.

  It should be noted that the disclosures of the above-mentioned patent documents and non-patent documents are incorporated herein by reference. Within the scope of the entire disclosure (including claims) of the present invention, the embodiments and examples can be changed and adjusted based on the basic technical concept. Various combinations or selections of various disclosed elements (including each element of each claim, each element of each embodiment, each element of each drawing, etc.) are possible within the scope of the claims of the present invention. . That is, the present invention of course includes various variations and modifications that could be made by those skilled in the art according to the entire disclosure including the claims and the technical idea.

  The above-described embodiment is appended as follows (however, it is not limited to the following).

(Appendix 1)
When there is a change in a predetermined radio parameter related to radio resource allocation,
A transmission amount estimation step of calculating an estimated value of a data transmission amount for the wireless terminal from a buffer that temporarily stores data addressed to the wireless terminal transmitted from the transmission source, considering the change of the wireless parameter;
Based on the estimated value of the data transmission amount from the buffer to the wireless terminal and the data storage amount addressed to the wireless terminal stored in the buffer, the data inflow amount to the wireless terminal to the buffer is calculated. An inflow control step to control;
A data flow rate control method comprising:

(Appendix 2)
The radio parameters are
The state of the application in the wireless terminal;
Radio channel quality between the radio base station and the radio terminal;
The data flow rate control method according to claim 1, wherein the data flow rate control method is changed based on at least one of the above.

(Appendix 3)
The radio parameters are
Allocation priority of radio resources in the radio terminal,
An index (QoE (Quality of Experience) index) indicating an application usage state in the wireless terminal;
Radio channel quality in the radio terminal;
Transmission power of a downlink data channel set in the wireless terminal,
Transmission mode (Transmission Mode) in the wireless terminal;
An antenna configuration in the wireless terminal;
The number of component carriers available to the wireless terminal;
Types of RAT (Radio Access Technology) that the wireless terminal can use;
The radio resource allocation policy in the base station;
The data flow rate control method according to appendix 1 or 2, characterized by including at least one of the above.

(Appendix 4)
The sending amount estimation step includes:
Calculating the expected value of the throughput of the radio section before and after the change of the radio parameter;
Estimating the data transmission amount until after a predetermined time has elapsed using the expected value of the throughput;
The data flow rate control method according to any one of supplementary notes 1 to 3, characterized by comprising:

(Appendix 5)
The inflow amount control step includes:
The data flow rate control method according to any one of appendices 1 to 4, further comprising a step of causing the data inflow amount to flow into the buffer.

(Appendix 6)
The inflow amount control step includes:
The data flow rate control method according to any one of appendices 1 to 4, wherein when the value of the data inflow amount is 0 or negative, the data inflow to the buffer is suppressed.

(Appendix 7)
Furthermore, an application information acquisition step for acquiring predetermined information regarding an application in the wireless terminal;
Detecting the change of the wireless parameter using predetermined information about the acquired application;
The data flow rate control method according to any one of supplementary notes 1 to 6, characterized in that:

(Appendix 8)
Furthermore, it has an application information acquisition step of acquiring predetermined information about the application in the wireless terminal,
The sending amount estimation step includes:
The data flow rate control method according to any one of appendices 1 to 6, wherein the data transmission amount is estimated using predetermined information related to the acquired application.

(Appendix 9)
A buffer for temporarily storing data addressed to the wireless terminal transmitted from the transmission source;
A function of transmitting data stored in the buffer to a wireless terminal based on a wireless resource allocation result;
When there is a change in a predetermined radio parameter related to the allocation of the radio resource, a transmission amount estimation unit that calculates an estimated value of the data transmission amount from the buffer to the wireless terminal in consideration of the change of the radio parameter When,
An inflow amount control unit that calculates an inflow amount of data addressed to the wireless terminal from the transmission source to the buffer based on the estimated value of the data transmission amount and the data accumulation amount accumulated in the buffer;
An information notification unit for notifying the transmission source of the data inflow amount;
A radio base station apparatus.

(Appendix 10)
The state of the application in the wireless terminal;
Radio channel quality between the radio base station and the radio terminal;
The radio base station apparatus according to appendix 9, further comprising: a change detection unit that detects a change in the radio parameter that is changed based on at least one of the radio parameters.

(Appendix 11)
The radio parameters are
Allocation priority of radio resources in the radio terminal,
An index (QoE (Quality of Experience) index) indicating an application usage state in the wireless terminal;
Radio channel quality in the radio terminal;
Transmission power of a downlink data channel set in the wireless terminal,
Transmission mode (Transmission Mode) in the wireless terminal;
An antenna configuration in the wireless terminal;
The number of component carriers available to the wireless terminal;
Types of RAT (Radio Access Technology) that the wireless terminal can use;
The radio resource allocation policy in the base station;
The radio base station apparatus according to appendix 9 or 10, characterized by including at least one of the following.

(Appendix 12)
The delivery amount estimation unit
Calculate the expected value of the throughput of the radio section before and after the change of the radio parameter,
The radio base station apparatus according to any one of appendices 9 to 11, wherein the data transmission amount until a predetermined time elapses is estimated using the expected value of the throughput.

(Appendix 13)
A function of acquiring predetermined information about an application in the wireless terminal;
The change detection unit
The radio base station apparatus according to appendix 10, wherein a change in the radio parameter is detected using predetermined information related to an application in the radio terminal.

(Appendix 14)
A function of acquiring predetermined information about an application in the wireless terminal;
The delivery amount estimation unit
The radio base station apparatus according to any one of appendices 9 to 12, wherein the data transmission amount is estimated using predetermined information related to an application in the radio terminal.

(Appendix 15)
A function for receiving data inflow information addressed to a wireless terminal calculated by a wireless base station via a communication network;
An inflow amount control unit that controls an amount of data addressed to the wireless terminal to be transmitted to the radio base station based on the data inflow amount information.

(Appendix 16)
The inflow control unit
When the data inflow information is positive, the data addressed to the wireless terminal is additionally transmitted to the radio base station by the data inflow amount,
The server apparatus according to supplementary note 15, wherein when the data inflow information is zero or negative, data addressed to the wireless terminal is not transmitted to the wireless base station or transmission is suppressed.

(Appendix 17)
A function that is connected between a radio base station and a server device and relays data addressed to a radio terminal transmitted from the server device to the radio base station;
A reception function for receiving data inflow information addressed to a wireless terminal calculated by the wireless base station from the wireless base station via a communication network;
A data amount control unit for controlling the amount of data addressed to the wireless terminal to be transmitted to the wireless base station based on the data inflow amount information;
A relay device comprising:

(Appendix 18)
An information acquisition unit for acquiring predetermined information regarding an application in the wireless terminal;
An information notification unit for notifying the radio base station of predetermined information related to the application;
The relay device according to appendix 17, further comprising:

(Appendix 19)
The inflow control unit
When the data inflow information is positive, the data addressed to the wireless terminal is additionally transmitted to the radio base station by the data inflow amount,
19. The relay device according to appendix 17 or 18, wherein when the data inflow information is zero or negative, data addressed to the wireless terminal is not transmitted to the wireless base station or transmission is suppressed.

(Appendix 20)
A radio base station comprising a buffer for temporarily storing data addressed to a radio terminal transmitted from a transmission source, and including a function of transmitting data stored in the buffer to the radio terminal based on a radio resource allocation result To the computer
When there is a change in a predetermined radio parameter related to the allocation of the radio resource, a process of calculating an estimated value of the amount of data transmitted from the buffer to the radio terminal in consideration of the change of the radio parameter;
Based on the estimated value of the data transmission amount and the data accumulation amount accumulated in the buffer, a process for calculating the data inflow amount addressed to the wireless terminal from the transmission source to the buffer;
A process of notifying the transmission source of the data inflow amount;
A program that executes

(Appendix 21)
The state of the application in the wireless terminal;
Radio channel quality between the radio base station and the radio terminal;
The program according to appendix 20, which causes the computer to execute a process of detecting a change in the wireless parameter that is changed based on at least one of the parameters.

(Appendix 22)
The radio parameters are
Allocation priority of radio resources in the radio terminal,
An index (QoE (Quality of Experience) index) indicating an application usage state in the wireless terminal;
Radio channel quality in the radio terminal;
Transmission power of a downlink data channel set in the wireless terminal,
Transmission mode (Transmission Mode) in the wireless terminal;
An antenna configuration in the wireless terminal;
The number of component carriers available to the wireless terminal;
Types of RAT (Radio Access Technology) that the wireless terminal can use;
The radio resource allocation policy in the base station;
The program according to appendix 20 or 21, characterized by including at least one of the above.

(Appendix 23)
The processing unit for calculating the estimated value of the delivery amount is
Calculate the expected value of the throughput of the radio section before and after the change of the radio parameter,
The program according to any one of appendices 20 to 22, which estimates the data transmission amount until a predetermined time has elapsed using the expected value of the throughput.

(Appendix 24)
Further comprising a process of acquiring predetermined information regarding an application in the wireless terminal;
The process of detecting the change is:
The program according to appendix 20, wherein the wireless parameter change is detected by using predetermined information related to an application in the wireless terminal.

(Appendix 25)
Further comprising a process of acquiring predetermined information regarding an application in the wireless terminal;
The process of estimating the delivery amount is
The program according to any one of appendices 20 to 23, wherein the data transmission amount is estimated using predetermined information related to an application in the wireless terminal.

(Appendix 26)
To the computer that constitutes the server device,
A process of receiving data inflow information addressed to a wireless terminal calculated by a wireless base station via a communication network;
Based on the data inflow information, a process for controlling the amount of data addressed to the wireless terminal to be transmitted to the wireless base station;
A program that executes

(Appendix 27)
When the data inflow information is positive, the data addressed to the wireless terminal is additionally transmitted to the radio base station by the data inflow amount,
The program according to appendix 26, which causes the computer to execute a process of not transmitting data addressed to the wireless terminal to the wireless base station or suppressing transmission when the data inflow information is zero or negative.

(Appendix 28)
A computer that is connected between a radio base station and a server device and that constitutes a relay device that relays data addressed to a radio terminal transmitted from the server device to the radio base station,
A process of receiving data inflow information addressed to a wireless terminal calculated by the wireless base station from the wireless base station via a communication network;
Based on the data inflow information, a process for controlling the amount of data addressed to the wireless terminal to be transmitted to the wireless base station;
A program that executes

(Appendix 29)
Processing for obtaining predetermined information regarding an application in the wireless terminal;
29. The program according to appendix 28, further causing the computer to execute a process of notifying the radio base station of predetermined information related to the application.

(Appendix 30)
When the data inflow information is positive, the data addressed to the wireless terminal is additionally transmitted to the radio base station by the data inflow amount,
The program according to appendix 28 or 29, further causing the computer to further execute a process of not transmitting data addressed to the radio terminal to the radio base station or suppressing transmission when the data inflow information is zero or negative. .

(Appendix 31)
A wireless terminal,
A radio base station;
A server device;
With
The radio base station is
A buffer for temporarily storing data addressed to the wireless terminal transmitted from the server device;
A function of transmitting data stored in the buffer to a wireless terminal based on a wireless resource allocation result;
When there is a change in a predetermined radio parameter related to the allocation of the radio resource, a transmission amount estimation unit that calculates an estimated value of the data transmission amount from the buffer to the wireless terminal in consideration of the change of the radio parameter When,
An inflow amount control unit that calculates an inflow amount of data addressed to the wireless terminal from the server device to the buffer based on the estimated value of the data transmission amount and the data accumulation amount accumulated in the buffer;
An information notification unit for notifying the server device of the data inflow amount;
Including
The server device
Receive the data inflow amount transmitted from the radio base station,
A communication system, comprising: an inflow amount control unit that controls an amount of data addressed to the wireless terminal to be transmitted to the radio base station based on the data inflow amount information.

(Appendix 32)
The radio base station is
The state of the application in the wireless terminal;
Radio channel quality between the radio base station and the radio terminal;
32. The communication system according to supplementary note 31, further comprising a change detection unit that detects a change in the wireless parameter that is changed based on at least one of the parameters.

(Appendix 33)
A function of acquiring predetermined information about an application in the wireless terminal;
The delivery amount estimation unit
33. The communication system according to appendix 31 or 32, wherein the data transmission amount is estimated using predetermined information related to an application in the wireless terminal.

(Appendix 34)
A wireless terminal,
A radio base station;
A server device;
A relay device connected between the radio base station and the server device;
With
The radio base station is
A buffer for temporarily storing data addressed to the wireless terminal transmitted from the server device via the relay device;
A function of transmitting data stored in the buffer to a wireless terminal based on a wireless resource allocation result;
When there is a change in a predetermined radio parameter related to the allocation of the radio resource, a transmission amount estimation unit that calculates an estimated value of the data transmission amount from the buffer to the wireless terminal in consideration of the change of the radio parameter When,
An inflow amount control unit that calculates an inflow amount of data addressed to the wireless terminal from the transmission source to the buffer based on the estimated value of the data transmission amount and the data accumulation amount accumulated in the buffer;
An information notification unit that notifies the relay apparatus of the data inflow amount;
Including
The relay device is
A reception function for receiving data inflow amount information addressed to the wireless terminal calculated by the wireless base station;
In relaying data addressed to the wireless terminal transmitted from the server device to the wireless base station, a data amount for controlling the data amount addressed to the wireless terminal to be transmitted to the wireless base station based on the data inflow amount information And a control unit.

(Appendix 35)
The relay device is
An information acquisition unit for acquiring predetermined information regarding an application in the wireless terminal;
35. The communication system according to claim 34, further comprising: an information notification unit that notifies the wireless base station of predetermined information related to the application.

(Appendix 36)
36. The communication system according to appendix 34 or 35, wherein the transmission amount estimation unit of the wireless base station estimates the data transmission amount using predetermined information related to an application in the wireless terminal.

(Appendix 37)
37. The communication system according to any one of appendices 34 to 36, wherein the relay device is arranged in a core network connected to the radio base station or a packet data network connected to the core network.

(Appendix 38)
The radio base station is
The state of the application in the wireless terminal;
Radio channel quality between the radio base station and the radio terminal;
38. The communication system according to any one of appendices 34 to 37, further including a change detection unit that detects a change in the wireless parameter that is changed based on at least one of the parameters.

(Appendix 39)
The radio parameters are
Allocation priority of radio resources in the radio terminal,
An index (QoE (Quality of Experience) index) indicating an application usage state in the wireless terminal;
Radio channel quality in the radio terminal;
Transmission power of a downlink data channel set in the wireless terminal,
Transmission mode (Transmission Mode) in the wireless terminal;
An antenna configuration in the wireless terminal;
The number of component carriers available to the wireless terminal;
Types of RAT (Radio Access Technology) that the wireless terminal can use;
The radio resource allocation policy in the base station;
39. The communication system according to appendix 33 or 38, comprising at least one of the above.

(Appendix 40)
In the radio base station,
The delivery amount estimation unit
Calculate the expected value of the throughput of the radio section before and after the change of the radio parameter,
35. The communication system according to appendix 31 or 34, wherein the data transmission amount until a predetermined time elapses is estimated using the expected value of the throughput.

1, 1A, 1B communication system
10,910 Wireless terminal
11 Mobile Access Network 20, 21, 920 Radio Base Station 20-1 Transceiver (TRX)
20-11 Transmitter (TX)
20-12 Receiver (RX)
20-13 Antenna 20-2 Information processing apparatus 20-21 CPU
20-22 storage device 20-3 communication interface 30, 31, 930 server device
30-1 Communication Interface 30-2 Information Processing Device 30-21 CPU
30-22 storage device 40 relay device 40-1 information processing device 40-2 communication interface 40-11 CPU
40-12 storage device 50, 940 communication line network 51 mobile core network 52 external network
201 Basic functions
202, 921 buffer
203, 213 Communication control unit
204 Change detection unit
205, 215 Output amount estimation unit
206 Inflow control unit
207 Information notification part
301 Basic functions
302 Inflow control unit
401 Basic functions
402 Information acquisition unit
403 Information notification unit
404 Inflow control unit 931 Storage device 950 Wireless interface 960 P-GW

Claims (10)

When there is a change in a predetermined radio parameter related to radio resource allocation,
A transmission amount estimation step of calculating an estimated value of a data transmission amount for the wireless terminal from a buffer that temporarily stores data addressed to the wireless terminal transmitted from the transmission source, considering the change of the wireless parameter;
Based on the estimated value of the data transmission amount from the buffer to the wireless terminal and the data storage amount addressed to the wireless terminal stored in the buffer, the data inflow amount to the wireless terminal to the buffer is calculated. An inflow control step to control;
A data flow rate control method comprising: A buffer for temporarily storing data addressed to the wireless terminal transmitted from the transmission source;
A function of transmitting data stored in the buffer to a wireless terminal based on a wireless resource allocation result;
When there is a change in a predetermined radio parameter related to the allocation of the radio resource, a transmission amount estimation unit that calculates an estimated value of the data transmission amount from the buffer to the wireless terminal in consideration of the change of the radio parameter When,
An inflow amount control unit that calculates an inflow amount of data addressed to the wireless terminal from the transmission source to the buffer based on the estimated value of the data transmission amount and the data accumulation amount accumulated in the buffer;
An information notification unit for notifying the transmission source of the data inflow amount;
A radio base station apparatus. A function for receiving data inflow information addressed to a wireless terminal calculated by a wireless base station via a communication network;
An inflow amount control unit that controls an amount of data addressed to the wireless terminal to be transmitted to the radio base station based on the data inflow amount information. A function that is connected between a radio base station and a server device and relays data addressed to a radio terminal transmitted from the server device to the radio base station;
A reception function for receiving data inflow information addressed to a wireless terminal calculated by the wireless base station from the wireless base station via a communication network;
A data amount control unit for controlling the amount of data addressed to the wireless terminal to be transmitted to the wireless base station based on the data inflow amount information;
A relay device comprising: A radio base station comprising a buffer for temporarily storing data addressed to a radio terminal transmitted from a transmission source, and including a function of transmitting data stored in the buffer to the radio terminal based on a radio resource allocation result To the computer
When there is a change in a predetermined radio parameter related to the allocation of the radio resource, a process of calculating an estimated value of the amount of data transmitted from the buffer to the radio terminal in consideration of the change of the radio parameter;
Based on the estimated value of the data transmission amount and the data accumulation amount accumulated in the buffer, a process for calculating the data inflow amount addressed to the wireless terminal from the transmission source to the buffer;
A process of notifying the transmission source of the data inflow amount;
A program that executes To the computer that constitutes the server device,
A process of receiving data inflow information addressed to a wireless terminal calculated by a wireless base station via a communication network;
Based on the data inflow information, a process for controlling the amount of data addressed to the wireless terminal to be transmitted to the wireless base station;
A program that executes A computer that is connected between a radio base station and a server device and that constitutes a relay device that relays data addressed to a radio terminal transmitted from the server device to the radio base station,
A process of receiving data inflow information addressed to a wireless terminal calculated by the wireless base station from the wireless base station via a communication network;
Based on the data inflow information, a process for controlling the amount of data addressed to the wireless terminal to be transmitted to the wireless base station;
A program that executes A wireless terminal,
A radio base station;
A server device;
With
The radio base station is
A buffer for temporarily storing data addressed to the wireless terminal transmitted from the server device;
A function of transmitting data stored in the buffer to a wireless terminal based on a wireless resource allocation result;
When there is a change in a predetermined radio parameter related to the allocation of the radio resource, a transmission amount estimation unit that calculates an estimated value of the data transmission amount from the buffer to the wireless terminal in consideration of the change of the radio parameter When,
An inflow amount control unit that calculates an inflow amount of data addressed to the wireless terminal from the server device to the buffer based on the estimated value of the data transmission amount and the data accumulation amount accumulated in the buffer;
An information notification unit for notifying the server device of the data inflow amount;
Including
The server device
Receive the data inflow amount transmitted from the radio base station,
A communication system, comprising: an inflow amount control unit that controls an amount of data addressed to the wireless terminal to be transmitted to the radio base station based on the data inflow amount information. A wireless terminal,
A radio base station;
A server device;
A relay device connected between the radio base station and the server device;
With
The radio base station is
A buffer for temporarily storing data addressed to the wireless terminal transmitted from the server device via the relay device;
A function of transmitting data stored in the buffer to a wireless terminal based on a wireless resource allocation result;
When there is a change in a predetermined radio parameter related to the allocation of the radio resource, a transmission amount estimation unit that calculates an estimated value of the data transmission amount from the buffer to the wireless terminal in consideration of the change of the radio parameter When,
An inflow amount control unit that calculates an inflow amount of data addressed to the wireless terminal from the transmission source to the buffer based on the estimated value of the data transmission amount and the data accumulation amount accumulated in the buffer;
An information notification unit that notifies the relay apparatus of the data inflow amount;
Including
The relay device is
A reception function for receiving data inflow amount information addressed to the wireless terminal calculated by the wireless base station;
In relaying data addressed to the wireless terminal transmitted from the server device to the wireless base station, a data amount for controlling the data amount addressed to the wireless terminal to be transmitted to the wireless base station based on the data inflow amount information And a control unit. The relay device is
An information acquisition unit for acquiring predetermined information regarding an application in the wireless terminal;
An information notification unit for notifying the radio base station of predetermined information related to the application,
The transmission amount estimation unit of the radio base station is
The communication system according to claim 9, wherein the data transmission amount is estimated using predetermined information related to an application in the wireless terminal.

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