JP7219900B2 - Wireless communication method, wireless communication system, base station device, wireless terminal, and wireless communication program - Google Patents

Description

The present invention relates to a radio communication method, radio communication system, base station apparatus, radio terminal, and radio communication program.

Based on a wide range of services and needs using mobile communication, a fifth-generation mobile communication system (5G) is being studied as a next-generation mobile communication system. The features of 5G include ultra-high speed, ultra-low latency, and multiple simultaneous connections, which are expected to create new industries and solve social issues.

In order to meet the quality requirements of various services, 5G uses various frequency bands, from low frequency bands such as 800 MHz, 2 GHz, sub-6 GHz band, or Wi-Fi (registered trademark) to high frequency bands such as millimeter wave bands. It consists of heterogeneous networks (Integrated Networks) to be utilized.

In order to effectively utilize this heterogeneous network, 5G is considering dual connectivity (see, for example, Non-Patent Document 1). Dual connectivity is a mechanism that enables wireless terminals to have interfaces (IFs) of different frequency bands and simultaneously connect to and communicate with multiple base stations.

In addition, 5G is expected to efficiently accommodate services by allocating each communication of diversified applications to a base station of an appropriate frequency band according to the required quality.

However, the method of determining the connection destination base station of each wireless terminal in dual connectivity and the routing setting method of each application after establishing connection with the base station are not clearly defined.

O.Semiari et.al., “Integrated Millimeter Wave and Sub-6 GHz Wireless Networks: A Roadmap for Joint Mobile Broadband and Ultra-Reliable Low-Latency Communications,”IEEE Wireless Communications, vol.26, no.2, pp. 109-115, April 2019

An object of the present invention is to provide a wireless communication method, a wireless communication system, a base station apparatus, a wireless terminal, and a wireless communication program capable of enabling efficient communication using different frequency bands.

A wireless communication method according to an aspect of the present invention includes one or more high frequency band base stations that perform wireless communication in a high frequency band, and one or more low frequency bands that perform wireless communication in a frequency band lower than the high frequency band base station. In a wireless communication method performed by a wireless communication system comprising a plurality of wireless terminals capable of wirelessly communicating with a base station and both the high frequency band base station and the low frequency band base station, radio waves are shielded by a shield. a high-frequency connection determination step in which the high-frequency band base station determines whether or not connection is permitted in response to a connection request with quality requirements for each application transmitted by the wireless terminal that does not support the wireless terminal; On the other hand, a high-frequency response control step in which the high-frequency band base station responds with a connection permission in the high-frequency band; a low-frequency connection determination step in which the low-frequency base station determines whether or not the connection is permitted; and the low-frequency base station responds to the wireless terminal that has been permitted to connect by the low-frequency connection determination step by allowing the connection in the low-frequency band. a low-frequency response control step for each of the wireless terminals, based on the response from each of the high-frequency base station and the low-frequency base station, and the congestion occurrence probability at the low-frequency base station, quality requirements for each application and a learning processing step of learning to select the high frequency band base station or the low frequency band base station as a connection destination so as to satisfy the following.

A wireless communication system according to an aspect of the present invention includes one or more high frequency band base stations that perform wireless communication in a high frequency band, and one or more low frequency bands that perform wireless communication in a frequency band lower than the high frequency band base station. In a wireless communication system comprising a base station and a plurality of wireless terminals capable of wirelessly communicating with both the high frequency band base station and the low frequency band base station, the high frequency band base station is blocked by radio waves due to a shield. a high-frequency connection determination unit that determines whether or not to allow connection in response to a connection request with quality requirements for each application transmitted by the unshielded wireless terminal; and a high-frequency response control unit that responds to the connection permission in the above, and the low-frequency band base station connects to the connection request sent by the wireless terminal to the wireless terminal for which the high-frequency band base station rejects the connection request. and a low-frequency response control unit that responds to the wireless terminal for which connection is permitted by the low-frequency connection determination unit, and a low-frequency response control unit that responds to the connection permission in the low-frequency band. Each terminal satisfies the quality requirement for each application based on the response from each of the high frequency band base station and the low frequency band base station and the congestion occurrence probability at the low frequency band base station, the high frequency band base station It is characterized by having a learning processing unit that performs learning to select a station or the low frequency band base station as a connection destination.

A base station apparatus according to an aspect of the present invention includes a high frequency band base station that performs wireless communication with a wireless terminal in a high frequency band, and a low frequency band base that performs wireless communication with the wireless terminal in a frequency band lower than that of the high frequency band base station. in a base station device comprising at least one station, the high-frequency band base station determines whether or not to accept a connection request with quality requirements for each application transmitted by the wireless terminal whose radio waves are not blocked by a shield. and a high-frequency response control unit that responds with a connection permission in a high-frequency band to the wireless terminal to which the high-frequency connection determination unit has permitted connection, wherein the low-frequency band base station a low-frequency connection determining unit for determining whether or not connection is permitted in response to a connection request transmitted by a wireless terminal to which a connection request has been rejected by a base station; and a low-frequency response control unit that responds to the terminal for connection permission in the low-frequency band.

A wireless terminal according to an aspect of the present invention includes one or more high frequency band base stations that perform wireless communication in a high frequency band, and one or more low frequency band that perform wireless communication in a frequency band lower than the high frequency band base station. A wireless terminal that is capable of wireless communication with any of the base stations is permitted to connect to a connection request with quality requirements for each application that is transmitted when the wireless terminal is not shielded from radio waves by a shield. Based on the response from each of the high frequency band base station and the low frequency band base station that permitted connection when the high frequency band base station refused the connection request, and the congestion occurrence probability at the low frequency band base station, the application a learning processing unit that performs learning to select the high frequency band base station or the low frequency band base station as a connection destination so as to satisfy the quality requirements for each, and the high frequency band base station selected by the learning processing unit as a connection destination or a connection request control unit that issues a connection request to the low frequency band base station.

According to the present invention, efficient communication can be enabled using different frequency bands.

1 is a diagram illustrating a basic configuration example of a wireless communication system according to an embodiment; FIG. 1 is a diagram illustrating an overview of the operation of a wireless communication system; FIG. FIG. 2 is a diagram exemplifying functions possessed by a high-frequency band base station; FIG. 2 is a diagram illustrating functions possessed by a low frequency band base station; FIG. 2 is a diagram illustrating functions of a wireless terminal; FIG. FIG. 2 illustrates variables for illustrating operation in a wireless communication system; FIG. 2 illustrates variables for illustrating operation in a wireless communication system; (a) is a diagram showing a connection request from a wireless terminal to a base station apparatus. (b) is a diagram showing a process of connection from a base station apparatus to a wireless terminal; (c) is a diagram showing a state in which the wireless terminal has decided to connect with the base station apparatus and a state in which learning is continued. (a) is a diagram showing a state in which each wireless terminal issues a connection request to the millimeter wave band interface of the base station apparatus. (b) is a diagram showing a state in which the base station apparatus selects a user with the highest utility. (c) is a diagram showing a state in which the base station apparatus has added a user located near the user to the cluster. (d) is a diagram showing a state in which beamforming is determined. (a) is a diagram showing a state in which each wireless terminal issues a connection request to a sub-6 GHz band interface of a base station apparatus. (b) is a diagram showing a state in which the base station apparatus selects a wireless terminal to be connected to the sub-6 GHz band interface. 1 is a diagram illustrating an example hardware configuration of a wireless terminal according to an embodiment; FIG. (a) is a diagram showing a basic configuration example of a wireless communication system. (b) is a diagram showing an operation example when the wireless communication system uses a high frequency band. (c) is a diagram showing an operation example when the wireless communication system uses a low frequency band.

First, the background that led to the present invention will be described. FIG. 12 is a diagram showing a configuration example and an operation example of the radio communication system 1 of the comparative example. FIG. 12(a) is a diagram showing a basic configuration example of the wireless communication system 1. As shown in FIG. FIG. 12(b) is a diagram showing an operation example when the wireless communication system 1 uses a high frequency band. FIG. 12(c) is a diagram showing an operation example when the wireless communication system 1 uses the low frequency band. Note that the radio communication system 1 is assumed to have the above-described 5G function.

As shown in FIG. 12(a), a wireless communication system 1 includes a plurality of base station apparatuses 2 each having a high frequency band interface (IF) and a low frequency band interface, and one base station device 2 each having a high frequency band interface and a low frequency band interface. and one or more wireless terminals 3 .

Specifically, the base station apparatus 2 has a function as a high frequency band base station such as a millimeter wave band and a function as a low frequency band base station such as a sub-6 GHz band. The wireless terminal 3 has a function as a high frequency band wireless terminal such as a millimeter wave band and a function as a low frequency band wireless terminal such as a sub-6 GHz band.

That is, the radio communication system 1 is a system having dual connectivity using different frequency bands. In the following description, it is assumed that millimeter wave band radio waves (beams) are emitted in the high frequency band, and sub-6 GHz band radio waves (beams) are emitted in the low frequency band.

In the wireless communication system 1, if the base station apparatus 2 to which the wireless terminal 3 is to be connected is determined at random without considering the required quality of the applications provided in the wireless terminal 3, and the routing settings for each application are performed, The following communication efficiency deterioration may occur.

For example, as shown in FIG. 12(b), when the base station apparatus 2 and the wireless terminal 3 perform communication in a high frequency band, if there is a shield 4 such as a tree on the communication path that blocks radio waves, Radio waves are blocked.

Specifically, when emitting radio waves in the millimeter waveband, the base station apparatus 2 performs beamforming in a direction in which the connected wireless terminals 3 are concentrated so as to maximize the utilization rate of the entire wireless communication system 1. (BF) is performed.

However, the transmission rate for the wireless terminal 3 located behind the shield 4 existing in the aiming direction of the BF emitted by the base station device 2 is drastically reduced. In other words, the transmission rate deteriorates due to the directivity of high-frequency band communication.

Further, as shown in FIG. 12(c), when the communication that fails to be accommodated in the high frequency band shifts to the low frequency band, the radio terminal 3 is simply connected to the base station apparatus 2 with the maximum received power. Then, depending on the arrangement of each wireless terminal 3, connections may be concentrated on a specific base station apparatus 2. FIG. In other words, the probability of congestion may increase in the base station apparatus 2 that performs low frequency band communication.

Therefore, in the radio communication system according to one embodiment, base station apparatuses and radio terminals are configured so as to enable efficient communication using different frequency bands.

FIG. 1 is a diagram showing a basic configuration example of a wireless communication system 10 according to one embodiment. As shown in FIG. 1, a radio communication system 10 has, for example, a base station device 20 and a radio terminal 30, and the base station device 20 is connected to a network 100. FIG. Note that the radio communication system 10 is assumed to have the above-described 5G function.

The base station device 20 has a high frequency band base station 40 and a low frequency band base station 60, and is a base station with dual connectivity. That is, the base station apparatus 20 has a high frequency band interface (IF) and a low frequency band interface.

The high frequency band base station 40 is connected to the network 100 and performs wireless communication with the wireless terminal 30 using a high frequency band (millimeter wave band interface) such as a millimeter wave band.

The low-frequency band base station 60 is connected to the network 100 and performs wireless communication with the wireless terminal 30 using a low-frequency band such as the sub-6 GHz band (sub-6 GHz band interface).

The wireless terminal 30 has a function as a high frequency band wireless terminal such as a millimeter wave band and a function as a low frequency band wireless terminal such as a sub-6 GHz band.

Next, an overview of the operation of the radio communication system 10 will be described with reference to FIG. FIG. 2 is a diagram illustrating an overview of the operation of the radio communication system 10. As shown in FIG. Here, it is assumed that the radio communication system 10 has two base station apparatuses 20 and eight radio terminals 30 are located around the two base station apparatuses 20 .

In the radio communication system 10, the radio terminal 30 operates in accordance with the high frequency band base station 40 or the low frequency band base station 60 provided in the base station device 20 so as to satisfy the quality requirements (quality requirements) of each application executed by the radio terminal 30. Select to configure the connection settings. Also, the wireless terminal 30 performs routing settings for each application.

At this time, the wireless terminal 30 repeats transmission of a connection request to the high-frequency band base station 40 and the low-frequency band base station 60 and reception of feedback (FB) information as a response to the connection request. Let the settings converge to meet your requirements.

The FB information includes the determination result of acceptance/rejection for each request sent by the wireless terminal 30, the wireless transmission rate of the other wireless terminals 30, and the requested rate of each application.

Specifically, the wireless terminal 30 performs reinforcement learning such as Q-learning (Q-learning), DQN (deep Q-learning), and DDQN (Double DQN) using the FB information as follows to converge the settings. Let

Reinforcement learning is an algorithm in which, for example, the wireless terminal 30 detects a current state and receives a correction value called a reward for taking a certain action, and corrects the effectiveness of the state/action pair with the reward. is. Here, for example, states, actions, and rewards in the wireless communication system 10 are defined as follows.

Assume that the state is a setting for selecting the current high frequency band base station 40 or low frequency band base station 60 and a routing setting for each application executed by the wireless terminal 30 .

Actions are settings for selecting the high frequency band base station 40 or low frequency band base station 60 to be requested next, and contents of routing settings for each application executed by the wireless terminal 30 .

It is assumed that the reward is a processed value of FB information.

Then, the radio communication system 10 repeats the following processes (A), (B), and (C) between the base station apparatus 20 and the radio terminal 30. FIG.

(A) The wireless terminal 30 requests the base station apparatus 20 for connection and routing setting for each application. Then, the wireless terminal 30 refers to the current learning information, calculates the current optimum connection and routing settings for each application, and notifies the target base station apparatus 20 of the connection request.

(B) The base station apparatus 20 performs predetermined control described later, and notifies the wireless terminal 30 of the response to the request from the wireless terminal 30 and information regarding the base station apparatus 20 . For example, the base station apparatus 20 notifies a response (connection availability) to the connection request transmitted by the wireless terminal 30 . Also, the base station apparatus 20 notifies the wireless terminal 30 of the requested quality, transmission rate, etc. of another wireless terminal 30 currently connected or requesting a connection as base station information.

As a specific example, in the base station device 20, the high-frequency band base station 40 is configured to maximize the radio efficiency (utility) of the entire radio communication system 10, where the radio terminals 30 are concentrated (concentration of connected radio terminals). BF (beam forming) control is performed with the aim set on the part).

At this time, the high-frequency band base station 40 acquires information as relative coordinates of each wireless terminal 30 with respect to the high-frequency band base station 40 via radio reception power. At the same time, the high frequency band base station 40 also calculates the wireless transmission rate in BF control based on the acquired information.

Also, the base station apparatus 20 acquires information indicating the requested bandwidth of each application executed by each wireless terminal 30 based on past communication results. Based on two pieces of information, the wireless transmission rate for each wireless terminal 30 and the required bandwidth of each application, the high-frequency band base station 40 selects the connection wireless terminal concentration unit as the direction in which utility is maximized.

Also, in the base station apparatus 20, the low-frequency band base station 60 determines whether or not the wireless terminal 30 can be connected when congestion occurs, and controls the selection of the wireless terminal 30 to which connection is permitted.

(C) The wireless terminal 30 selects the high frequency band base station 40 or the low frequency band base station 60 and performs routing for each application executed by the wireless terminal 30 using the response and base station information transmitted by the base station device 20. Perform processing to learn Here, the wireless terminal 30 updates learning information regarding control by reinforcement learning or deep reinforcement learning.

The radio communication system 10 is controlled and learned by the radio terminal 30 and operates as follows.

First, the high-frequency band base station 40 performs beamforming in the direction of the wireless terminal 30 that has no shield 4 on the communication path, and connects only to the wireless terminal 30 .

The low frequency band base station 60 accommodates the wireless terminal 30 with the shield 4 on the communication path. In addition, the low frequency band base station 60 connects the base station device 20 to the radio terminals 30 that the high frequency band base station 40 cannot accommodate, by dual connectivity.

When connecting to the low frequency band base station 60, the wireless terminal 30 selects and connects to the low frequency band base station 60 that can minimize the bias in the radio wave utilization rate. Also, the wireless terminal 30, which is connected to both the high frequency band base station 40 and the low frequency band base station 60, sets the routing of each application so as to minimize the congestion probability due to each connection.

Next, configuration examples of the high frequency band base station 40, the low frequency band base station 60, and the wireless terminal 30 will be shown, and the wireless communication system 10 will be described in detail.

FIG. 3 is a diagram illustrating functions of the high frequency band base station 40. As shown in FIG. As shown in FIG. 3, the radio frequency band base station 40 includes an antenna section 400, an RF (Radio Frequency) section 402, a transmission/reception section 404, an IF (interface) section 406, a transmission rate measurement section 408, a media access control (MAC) measurement It has a section 410 , a high frequency connection determination section 412 , a high frequency response control section 414 and a BF (beam forming) control section 416 .

In the high-frequency band base station 40 , the transmitting/receiving section 404 transmits and receives, for example, millimeter-wave radio waves via the antenna section 400 and the RF section 402 . Further, high-frequency band base station 40 transmits and receives information to and from other base station apparatus 20 via network 100 through IF section 406 .

Transmission rate measurement section 408 measures the transmission rate of other base station apparatus 20 and the transmission rate of its own station based on the information acquired via IF section 406, and sends the measurement result to high-frequency connection determination section 412. Output.

The MAC measurement unit 410 measures the media access of other base station devices 20 and the media access of the own station based on the information acquired via the IF unit 406, and sends the measurement result to the high frequency connection determination unit 412. output.

Based on the information input from the transmission/reception unit 404, the transmission rate measurement unit 408, and the MAC measurement unit 410, the high-frequency connection determination unit 412 determines the quality requirements for each application transmitted by the wireless terminal 30 whose radio waves are not shielded by a shield. , and outputs the determination result to the high-frequency response control unit 414 and the BF control unit 416 .

High-frequency response control section 414 controls the response to wireless terminal 30 that has made a connection request. For example, the high-frequency response control unit 414 responds to the wireless terminal 30 to which the high-frequency connection determination unit 412 has permitted connection, via the transmission/reception unit 404, the RF unit 402, and the antenna unit 400, permitting connection in the high-frequency band.

The BF control unit 416 controls beamforming output by the RF unit 402 and the antenna unit 400 based on whether connection is possible or not determined by the high-frequency connection determination unit 412 . For example, the BF control unit 416 performs beamforming control aimed at the wireless terminal 30 that does not have a shield 4 (see FIG. 2) on the communication path.

FIG. 4 is a diagram illustrating the functions of the low frequency band base station 60. As shown in FIG. As shown in FIG. 4, the low frequency band base station 60 includes an antenna section 600, an RF (Radio Frequency) section 602, a transceiver section 604, an IF (interface) section 606, a transmission rate measurement section 608, a media access control (MAC) It has a measurement section 610 , a low frequency connection determination section 612 and a low frequency response control section 614 .

In the low-frequency band base station 60 , the transmitting/receiving section 604 transmits and receives radio waves in, for example, the sub-6 GHz band via the antenna section 600 and the RF section 602 . Also, low-frequency band base station 60 transmits and receives information to and from other base station apparatus 20 via network 100 through IF section 606 .

Transmission rate measurement section 608 measures the transmission rate of other base station apparatus 20 and the transmission rate of the own station based on the information acquired via IF section 606, and sends the measurement result to low frequency connection determination section 612. output.

The MAC measurement unit 610 measures the media access of other base station devices 20 and the media access of the own station based on the information acquired via the IF unit 606, and sends the measurement result to the low frequency connection determination unit 612. Output for

Based on the information input from the transmitting/receiving unit 604, the transmission rate measuring unit 608, and the MAC measuring unit 610, the low-frequency connection determination unit 612 sends a wireless It determines whether or not the connection can be established in response to the connection request transmitted by the terminal 30 , and outputs the determination result to the low-frequency response control section 614 .

The low-frequency response control section 614 controls responses to the wireless terminal 30 that has made a connection request. For example, the low-frequency response control unit 614 responds to the wireless terminal 30 to which the low-frequency connection determination unit 612 has permitted connection via the transmission/reception unit 604, the RF unit 602, and the antenna unit 600 to permit connection in the low-frequency band. do.

FIG. 5 is a diagram illustrating functions of the wireless terminal 30. As shown in FIG. As shown in FIG. 5, the wireless terminal 30 includes an antenna section 300, a high frequency band RF section 302, a high frequency band transmission/reception section 304, an antenna section 306, a low frequency band RF section 308, a low frequency band transmission/reception section 310, and an application management section 312. , a routing setting unit 314 , a connection request control unit 316 , a storage unit 318 , and a learning processing unit 320 .

In the wireless terminal 30 , the high frequency band transmitting/receiving section 304 transmits and receives, for example, millimeter wave band radio waves via the antenna section 300 and the high frequency band RF section 302 . Also, in the wireless terminal 30 , the low-frequency band transmitting/receiving section 310 transmits and receives, for example, sub-6 GHz band radio waves via the antenna section 306 and the low-frequency band RF section 308 .

The application management unit 312 manages each application provided in the wireless terminal 30 .

The routing setting unit 314 performs routing setting for each application managed by the application management unit 312 and outputs the setting contents to the connection request control unit 316 . Note that the routing setting unit 314 updates the routing settings according to the results of reinforcement learning or deep reinforcement learning performed by the learning processing unit 320 .

The connection request control unit 316 controls connection requests to the base station device 20 according to the routing set by the routing setting unit 314 and the result of reinforcement learning or deep reinforcement learning performed by the learning processing unit 320 .

The storage unit 318 stores the information received by the high frequency band transmission/reception unit 304 and the low frequency band transmission/reception unit 310 and the learning results of the learning processing unit 320 .

The learning processing unit 320 performs reinforcement learning or deep reinforcement learning based on the information stored in the storage unit 318 and outputs the learning result to the routing setting unit 314 and the connection request control unit 316 .

For example, the learning processing unit 320 satisfies the quality requirements for each application based on the response from each of the high frequency band base station 40 and the low frequency band base station 60, and the congestion occurrence probability at the low frequency band base station 60. Learning to select the high frequency band base station 40 or the low frequency band base station 60 as a connection destination is performed.

In addition, the learning processing unit 320 detects the current connection state of the wireless terminal 30, acquires a reward for the action of requesting connection to the high frequency band base station 40 or the low frequency band base station 60, Perform reinforcement learning or deep reinforcement learning that compensates for the effectiveness of combinations of states and actions with rewards.

Next, the operation of the radio communication system 10 will be described in detail. Note that the variables shown in FIGS. 6 and 7 are used here to illustrate the operation in the wireless communication system 10. FIG.

The communication interfaces provided by the base station apparatus b (APb) and the wireless terminal k (user k) shown in FIG. 6 are represented by the following equation (1).

The radio wave in the millimeter wave band has a larger capacity to accommodate the wireless terminal k than the radio wave in the sub-6 GHz band. However, they are easily blocked by shields. Here, the radio waves in the millimeter wave band are represented by the following equation (2).

On the other hand, the radio wave in the sub-6 GHz band has a smaller capacity to accommodate the wireless terminal k than the radio wave in the millimeter wave band, but is more difficult to be shielded than the radio wave in the millimeter wave band and has high reliability.

Each wireless terminal k requests a connection with the quality requirements of application set _Fk . Each application must meet its own quality requirements.

Therefore, the wireless communication system 10 "compensates" for the required bandwidth R _kf of the application f in the wireless terminal k to the minimum necessary, suppresses the load φ _b on the base station apparatus b, and satisfies the following equations (3) to (8). ), the utility function (radio wave utilization efficiency) u of the entire system is maximized.

FIG. 8 is a diagram showing an operation sequence ((a) to (c)) of the radio communication system 10. As shown in FIG. FIG. 8(a) is a diagram showing a connection request from the wireless terminal k to the base station apparatus b. FIG. 8(b) is a diagram showing the process of connection from the base station apparatus b to the wireless terminal k. FIG. 8(c) is a diagram showing a state in which the wireless terminal k has determined connection with the base station apparatus b and a state in which learning is continued.

In FIG. 8(a), state s _k (t) indicates that the current wireless terminal k (user k) satisfies the quality requirements of the application and is connected to the base station apparatus b at time t, Specifically, it is represented by the following formula (9).

The density of the state _Sk is represented by the following equation (10), where (the number of base stations.times.the number of bands).perspectiveto.the number of applications. Here, there are two bands, high frequency and low frequency.

Also, action a _k (t) is the connection that wireless terminal k next selects and requests at time t in order to execute an application on base station device b, specifically the following equation (11): , (12).

The density of the behavior _Ak is represented by the following equation (13), where (the number of base stations.times.the number of bands).perspectiveto.the number of applications. Here, there are two bands, high frequency and low frequency.

As described above, the wireless terminal k has a function of performing reinforcement learning using DQN, for example, and issues a connection request to the base station apparatus b for each application.

As shown in FIG. 8(b), in response to a connection request from wireless terminal k that satisfies the quality requirements for each application in the millimeter wave band, base station apparatus b responds to the position of wireless terminal k and radio wave usage of base station apparatus b. Based on the efficiency, the wireless terminal k to be permitted to connect is selected.

In addition, the base station apparatus b permits connection based on the position of the wireless terminal k and the radio wave utilization efficiency of the base station apparatus b in response to a connection request from the wireless terminal k that satisfies the quality requirements for each application in the sub-6 GHz band. Select the wireless terminal k to be used. At this time, if the base station apparatus b is overloaded, it drops the wireless terminal k with the heaviest load.

Then, the base station apparatus b uses the FB information to reply to the wireless terminal k as to whether or not the connection is possible.

As shown in FIG. 8(c), the wireless terminal k calculates the reward represented by the following formulas (14) to (16) based on the FB information, updates DQN or DDQN and performs reinforcement learning, Move to a new state.

Next, the algorithm for connecting from the base station apparatus b to the wireless terminal k shown in FIG. 8(b) will be described in more detail with reference to FIGS. 9 and 10. FIG.

FIG. 9 is a diagram schematically showing an algorithm by which the base station apparatus b selects a wireless terminal k (user u) to be permitted to connect using the millimeter waveband interface. FIG. 9(a) is a diagram showing a state in which each wireless terminal k (each user u) makes a connection request to the millimeter waveband interface of the base station apparatus b. FIG. 9(b) is a diagram showing a state in which the base station apparatus b selects user _u2 with the highest utility (radio wave utilization efficiency). FIG. 9(c) is a diagram showing a state in which the base station apparatus b adds user _u1 located near user _u2 to cluster _Cb . FIG. 9(d) is a diagram showing a state in which the base station apparatus b adds user _u1 located near user _u2 to the cluster and determines beamforming.

As shown in FIG. 9(a), when each wireless terminal k (users u ₁ to u ₃ ) makes a connection request, the base station apparatus b minimizes the beam width θ _bk to achieve practical (utility) Select the user u ₂ for which is the highest.

As shown in FIG. 9(b), the base station apparatus b adds the selected user _u2 to the cluster _Cb represented by the following equation (17).

At this time, the users u ₁ and u ₃ are candidates to be added to the beam irradiation targets located near the user u ₂ . If the formula (18) below is satisfied, the base station apparatus b adds the user u in question to the cluster _Cb shown in the formula (17) above.

In the example shown in FIG. 9(c), assuming that user u ₁ satisfies the above equation (18), the base station apparatus b assigns user u ₁ to cluster C _b as shown in the following equation (19). to add.

Next, the base station apparatus b adds another user u ₃ located in the vicinity of user u ₂ to cluster C _b . Compare the merit function with the base station's merit function, which is a function of the optimized beam direction and beam width before adding user u ₃ to cluster C _b , as shown in equation (20) below.

Here, the optimized base station merit function after adding user _u3 to cluster _Cb is smaller than the optimized base station merit function before adding user _u3 to cluster _Cb . ((d) in FIG. 9), the base station apparatus b determines the cluster _Cb as shown in the above equation (19).

FIG. 10 is a diagram schematically showing an algorithm by which the base station apparatus b selects a wireless terminal k (user u) to which connection is permitted using a sub-6 GHz band interface. FIG. 10(a) is a diagram showing a state in which each wireless terminal k (each user u ₁ to u ₃ ) makes a connection request to the sub-6 GHz band interface of the base station apparatus b. FIG. 10(b) is a diagram showing a state in which the base station apparatus b selects a wireless terminal k (each user u) to be connected to the sub-6 GHz band interface.

When each wireless terminal k (each user u ₁ to u ₃ ) makes a connection request to the sub-6 GHz band interface of the base station device b (FIG. 10(a)), the base station device b For example, users u ₂ and u ₃ with the highest utility) are selected. At this time, the base station apparatus b drops users u ₁ and u ₄ with heavy loads (low utility).

Note that each function of the wireless terminal 30, the high frequency band base station 40, and the low frequency band base station 60 may be configured partially or wholly by hardware, or may be implemented by a program executed by a processor such as a CPU. may be configured as

That is, the wireless terminal 30, the high frequency band base station 40, and the low frequency band base station 60 can each be realized using a computer and a program, and the program can be recorded on a storage medium or provided through a network. It is possible.

FIG. 11 is a diagram showing a hardware configuration example of the wireless terminal 30. As shown in FIG. As shown in FIG. 11, the wireless terminal 30 has an input unit 70, an output unit 71, a communication unit 72, a CPU 73, a memory 74, and an HDD 75 connected via a bus 76, and has functions as a computer. Also, the wireless terminal 30 can input/output data to/from the storage medium 77 .

The input unit 70 is, for example, a keyboard or the like. The output unit 71 is, for example, a display device such as a display. The communication unit 72 is, for example, a wireless network interface.

The CPU 73 controls each part constituting the wireless terminal 30 and performs the above-described calculations and the like. The memory 74 and HDD 75 store data and the like. The storage medium 77 can store a wireless communication program and the like for executing functions of the wireless terminal 30 . Note that the architecture configuring the wireless terminal 30 is not limited to the example shown in FIG. Also, the high frequency band base station 40 and the low frequency band base station 60 have the same hardware configuration as the wireless terminal 30 .

As described above, in the wireless communication system 10 according to one embodiment, the high-frequency band base station 40 is capable of connecting to a connection request with quality requirements for each application transmitted by the wireless terminal 30 whose radio waves are not shielded by the shield 4. The low-frequency band base station 60 determines whether or not the wireless terminal 30, to which the high-frequency band base station 40 has rejected the connection request, can connect to the connection request sent by the wireless terminal 30. Based on the response from each of the high frequency band base station 40 and the low frequency band base station 60, and the probability of congestion occurrence at the low frequency band base station 60, the high frequency band base station 40 so that each satisfies the quality requirements for each application. Alternatively, since learning is performed to select the low frequency band base station 60 as a connection destination, efficient communication can be enabled using different frequency bands.

Reference Signs List 10: Radio communication system 20: Base station device 30: Radio terminal 40: High frequency band base station 60: Low frequency band base station 70: Input unit 71 ... output section, 72 ... communication section, 73 ... CPU, 74 ... memory, 75 ... HDD, 76 ... bus, 77 ... storage medium, 400 ... antenna section , 402...RF unit, 404...Transceiver unit, 406...IF unit, 408...Transmission rate measurement unit, 410...MAC measurement unit, 412...High frequency connection determination unit, 414. High-frequency response control unit 416 BF control unit 600 Antenna unit 602 RF unit 604 Transmitting/receiving unit 606 IF unit 608 Transmission rate measurement Unit 610 MAC measurement unit 612 Low frequency connection determination unit 614 Low frequency response control unit 300 Antenna unit 302 High frequency band RF unit 304 High frequency band transmitting/receiving unit 306 Antenna unit 308 Low frequency band RF unit 310 Low frequency band transmitting/receiving unit 312 Application management unit 314 Routing setting unit 316. ... connection request control unit, 318 ... storage unit, 320 ... learning processing unit,

Claims (8)

One or more high frequency band base stations that perform wireless communication in a high frequency band, one or more low frequency band base stations that perform wireless communication in a frequency band lower than the high frequency band base station, and the high frequency band base station and the low frequency band base station. In a radio communication method performed by a radio communication system comprising a plurality of radio terminals capable of radio communication with any of frequency band base stations,
a high-frequency connection determination step in which the high-frequency band base station determines whether or not a connection request with quality requirements for each application transmitted by the wireless terminal whose radio waves are not blocked by a shield is permitted;
a high-frequency response control step in which the high-frequency band base station responds with a connection permission in a high-frequency band to the wireless terminal for which connection is permitted by the high-frequency connection determination step;
a low-frequency connection determination step of determining, by the low-frequency band base station, whether or not the wireless terminal, to which the high-frequency band base station has rejected the connection request, can be connected to a connection request transmitted by the wireless terminal;
a low-frequency response control step in which the low-frequency band base station responds with a connection permission in the low-frequency band to the wireless terminal for which connection is permitted by the low-frequency connection determination step;
The high frequency band so that each of the wireless terminals satisfies the quality requirements for each application based on the response from each of the high frequency band base station and the low frequency band base station and the probability of congestion occurrence at the low frequency band base station. and a learning processing step of learning to select a base station or the low frequency band base station as a connection destination. In the learning process step,
wherein the wireless terminal detects a state associated with a current connection and then obtains a reward for the action of requesting a connection from the high band base station or the low band base station to determine whether the combination of the state and the action is valid. 2. The wireless communication method according to claim 1, wherein reinforcement learning is performed to correct the sex by the reward. One or more high frequency band base stations that perform wireless communication in a high frequency band, one or more low frequency band base stations that perform wireless communication in a frequency band lower than the high frequency band base station, and the high frequency band base station and the low frequency band base station. In a wireless communication system comprising a plurality of wireless terminals enabled for wireless communication with any of the frequency band base stations,
The high-frequency band base station,
a high-frequency connection determination unit that determines whether or not a connection can be made in response to a connection request with quality requirements for each application transmitted by the wireless terminal whose radio waves are not blocked by a shield;
a high-frequency response control unit that responds with a connection permission in a high-frequency band to the wireless terminal for which connection is permitted by the high-frequency connection determination unit;
The low frequency band base station,
a low-frequency connection determining unit that determines whether or not a connection can be established in response to a connection request transmitted by the wireless terminal, for which the high-frequency band base station has rejected the connection request;
a low-frequency response control unit that responds with a connection permission in a low-frequency band to the wireless terminal that the low-frequency connection determination unit has permitted connection;
Each of the wireless terminals includes:
Based on the response from each of the high frequency band base station and the low frequency band base station, and the probability of congestion occurrence in the low frequency band base station, the high frequency band base station or the low frequency band base station or the low frequency band base station to meet the quality requirements for each application A wireless communication system, comprising: a learning processing unit that learns to select a frequency band base station as a connection destination. The learning processing unit
Detecting the state of the current connection of the wireless terminal, and then obtaining a reward for the action of requesting a connection from the high frequency band base station or the low band base station, and validating the combination of the state and the action. 4. The radio communication system according to claim 3, wherein reinforcement learning is performed to correct the sex by the reward. A base station apparatus comprising at least one of a high frequency band base station that performs wireless communication with a wireless terminal in a high frequency band and a low frequency band base station that performs wireless communication with a wireless terminal in a frequency band lower than that of the high frequency band base station ,
The high-frequency band base station,
a high-frequency connection determination unit that determines whether or not a connection can be made in response to a connection request with quality requirements for each application transmitted by the wireless terminal whose radio waves are not blocked by a shield;
a high-frequency response control unit that responds with a connection permission in a high-frequency band to the wireless terminal for which connection is permitted by the high-frequency connection determination unit;
The low frequency band base station,
a low-frequency connection determining unit that determines whether or not a connection can be established in response to a connection request transmitted by the wireless terminal, for which the high-frequency band base station has rejected the connection request;
and a low-frequency response control unit that responds to the wireless terminal for which connection has been permitted by the low-frequency connection determination unit, with a connection permission in a low-frequency band. Wireless communication is enabled with both one or more high frequency band base stations that wirelessly communicate in a high frequency band and one or more low frequency band base stations that wirelessly communicate in a frequency band lower than the high frequency band base station. in a wireless terminal that
The high-frequency band base station that permits connection to a connection request with quality requirements for each application that is transmitted when the wireless terminal is not blocked by a shield, and the high-frequency band base station rejects the connection request. Based on the response from each of the low-frequency band base stations that permitted connection when the a learning processing unit that learns to select a low-frequency base station as a connection destination;
a connection request control unit that issues a connection request to the high frequency band base station or the low frequency band base station selected as a connection destination by the learning processing unit. A wireless communication program for causing a computer to function as each part of the base station apparatus according to claim 5. A wireless communication program for causing a computer to function as each part of the wireless terminal according to claim 6.

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