Communication control method and communication controller in mobile communication system

Abstract

To efficiently utilize a communication resource in a mobile communication system.SOLUTION: A communication control method in a mobile communication system is provided. The mobile communication system comprises a base station, a management device for managing registration information on a user terminal existing in a communication area of the base station, and a relay for relaying communication between the base station and an external network. The communication control method includes the steps of; acquiring the total number of in-zone users of the base station from the management device; acquiring the total number of communication users from the base station; determining entropy based on the total number of in-zone users and the total number of communication users; setting a communication band of the base station to the relay on the basis of the entropy.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a communication control method and a communication control apparatus in a mobile communication system.

Background Art

[0002] In a conventional mobile communication system, generally, regardless of the number of resident users or the number of users actually communicating within the communication area of a base station, the communication bandwidth is set to the same value in all base stations. Further, since the data communication path assigned to a user is released when the communication is not active for a certain period of time (see, for example, Non-Patent Document 1), there is a possibility that the communication bandwidth of the base station is not efficiently utilized.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Therefore, it is desired to efficiently utilize communication resources in a mobile communication system.

Means for Solving the Problems

[0005] According to one aspect of the present invention, there is provided a communication control method in a mobile communication system. The mobile communication system includes a base station, a management device that manages registration information of user terminals located within the communication area of the base station, and a relay device that relays communication between the base station and an external network. The communication control method includes: obtaining, from the management device, the total number of users located within the communication area of the base station, where the total number of users located within the communication area represents the total number of user terminals located within the communication area of the base station; obtaining, from the base station, the total number of communication users of the base station, where the total number of communication users represents the total number of user terminals that are communicating user data via the relay device among the user terminals located within the communication area of the base station; determining an entropy based on the total number of users located within the communication area and the total number of communication users; and setting, based on the entropy, the communication bandwidth of the base station for the relay device.

[0006] Also, according to one aspect of the present invention, the entropy may be defined by an expression based on the ratio of the total number of users located within the communication area and the total number of communication users.

[0007] Also, according to one aspect of the present invention, when the ratio of the total number of communication users to the total number of users located within the communication area is p, the entropy is given by the following expression Entropy = -p × log 2 p - (1 - p) × log 2 (1 - p) and may be defined in this way.

[0008] Also, according to one aspect of the present invention, the method further includes calculating an average value of the entropy determined in the determining step over a predetermined period, and the setting step may include setting, based on the calculated average value of the entropy, the communication bandwidth of the base station for the relay device.

[0009] Also, according to one aspect of the present invention, the method further includes calculating an estimated value of the entropy using the maximum likelihood estimation method or the least squares method based on a plurality of entropies over a predetermined period determined in the determining step, and the setting step may include setting the communication band of the base station to the relay device based on the estimated value of the entropy.

[0010] Also, according to one aspect of the present invention, in the setting step, the communication band of the base station may be set to the product of the maximum communication capacity of the base station and the entropy.

[0011] Also, according to one aspect of the present invention, there is provided a communication control device in a mobile communication system, the mobile communication system including a base station, a management device that manages registration information of user terminals located in the communication area of the base station, and a relay device that relays communication between the base station and an external network. The communication control device includes a communication unit that acquires the total number of users present in the base station from the management device and acquires the total number of communication users of the base station from the base station. The total number of users present represents the total number of user terminals located in the communication area of the base station, and the total number of communication users represents the total number of user terminals that are communicating user data via the relay device among the user terminals located in the communication area of the base station. The communication control device further includes an entropy calculation unit that calculates entropy based on the total number of users present and the total number of communication users, and a band setting unit that sets the communication band of the base station to the relay device based on the entropy.

Advantages of the Invention

[0012] According to the present invention, efficient utilization of communication resources in a mobile communication system can be achieved.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0015] FIG. 1 is a diagram showing an example of the configuration of a mobile communication system 10 according to an embodiment of the present invention. The mobile communication system 10 includes a user terminal 100, a base station 200, and a core network 300. FIG. 1 illustrates a mobile communication system 10 compliant with the 5th generation (5G) communication standard. The core network 300 includes nodes such as an AMF (Access and Mobility Management Function) 310, a UDM (Unified Data Management) 320, a UDR (Unified Data Repository) 330, one or more routers 340, a UPF (User Plane Function) 350, an SMF (Session Management Function) (not shown), and a PCF (Policy Control Function) (not shown). Note that the mobile communication system 10 may comply with the 4th generation (4G) communication standard.

[0016] AMF310 is a node that provides a mobility control function and performs mobility control such as location registration, paging, and handover. UDM320 is a node that manages user contract information and authentication information. UDR330 is a node (subscriber database management device) that stores a subscriber database holding the identification number and presence information of user terminal 100. SMF is a node that provides a session management function and performs session maintenance, establishment, modification, and release. PCF is a node that provides a policy control function regarding quality such as data transfer speed and delay time. UPF350 is a node that communicates user data between user terminal 100 and external network 500 (for example, the Internet). Each of these nodes complies with the 5G communication standard, and the detailed description thereof is omitted here.

[0017] User terminal 100 is a wireless communication device such as a mobile phone terminal or a smartphone. When user terminal 100 is within the communication area of base station 200, it transmits its subscriber identification information (IMSI: International Mobile Subscriber Identity) to UDR330 via AMF310 and UDM320 in sequence. By registering this subscriber identification information in UDR330, communication services such as voice calls and data communication in mobile communication system 10 are provided to user terminal 100. As a result, user terminal 100 can communicate with external network 500 via router 340 and UPF350.

[0018] More specifically, when the subscriber identification information of the user terminal 100 is registered in the UDR 330, a data communication path (U-plane) for the user terminal 100 to communicate with the external network 500 is formed on the path from the user terminal 100 through the base station 200 and the router 340 to the UPF 350. Generally, an expiration date is set for this data communication path. For example, if the period during which the user terminal 100 does not perform communication using the data communication path continues for a predetermined time (e.g., several tens of seconds to several minutes), this data communication path is discarded. When the user terminal 100 attempts to resume communication with the external network 500, a new data communication path for the user terminal 100 is prepared. In this way, the data communication path is dynamically generated and deleted, and information on how many user terminals 100 are actually performing user data communication is managed by the base station 200.

[0019] In the present embodiment, the core network 300 of the mobile communication system 10 further includes a communication control device 360 for controlling the communication bandwidth of the router 340 and / or the UPF 350. The communication control device 360 is configured to set an appropriate communication bandwidth of the base station 200 for the router 340 and / or the UPF 350 according to the dynamically changing number of user terminals 100 actually performing communication. Note that in this specification, the "communication bandwidth" means the amount of data that can pass through one base station 200 per unit time, and may also be referred to as communication capacity or communication speed. For example, the communication bandwidth can be expressed in the unit of "Gbps (gigabits per second)".

[0020] FIG. 2 is a block diagram showing the functional configuration of the communication control device 360 in the mobile communication system 10 according to an embodiment of the present invention. The communication control device 360 includes a communication unit 362, an entropy calculation unit 364, and a bandwidth setting unit 366. Note that the communication control device 360 can be realized by a computer including a processor and a memory.

[0021] The communication unit 362 of the communication control device 360 is configured to obtain from the UDR 330 the total number of user terminals 100 located within the communication area of the base station 200 (hereinafter referred to as the "total number of on-site users"). As described above, when the user terminal 100 enters the communication area of the base station 200 (for example, when the user terminal 100 moves from the communication area of another base station to the communication area of the base station 200), the subscriber identification information of the user terminal 100 is registered in the UDR 330. The UDR 330 holds the subscriber identification information of all user terminals 100 located within the communication area of the base station 200, and based on this, can notify the communication control device 360 of the total number of on-site users.

[0022] The communication unit 362 of the communication control device 360 is also configured to obtain from the base station 200 the total number of user terminals 100 among the user terminals 100 located within the communication area of the base station 200 that are currently performing user data communication via a data communication path (U-plane) (hereinafter referred to as the "total number of communication users"). As described above, the data communication path between the user terminal 100 and the UPF 350 is dynamically generated and deleted (for example, in response to the issuance of a communication request from the user terminal 100 or the completion of the requested communication process). The base station 200 grasps the number of currently active data communication paths, and can notify the communication control device 360 of the total number as the total number of communication users. Note that the "currently active data communication path" may include not only the data communication path that is currently actually executing user data communication processing, but also the data communication path for which the requested communication process has been completed but has not yet been discarded (i.e., the expiration date has not expired).

[0023] The communication unit 362 may repeatedly obtain the total number of on-site users and the total number of communication users at a predetermined time interval. For example, the communication unit 362 can obtain the total number of on-site users and the total number of communication users from the UDR 330 or the base station 200 at an arbitrary time interval such as every 5 minutes, every 15 minutes, or every hour.

[0024] The entropy calculation unit 364 of the communication control device 360 is configured to calculate the entropy based on the total number of present users and the total number of communication users of the base station 200. For example, the entropy can be defined by the following equation when the ratio of the total number of communication users to the total number of present users of the base station 200 is p (i.e., p = total number of communication users / total number of present users). Entropy = -p × log 2 p - (1 - p) × log 2 (1 - p) ……(1)

[0025] Here, generally, in a mobile communication system 10 such as a mobile phone communication network based on the 5G or 4G communication standard, there is an upper limit on the number of user terminals 100 that can simultaneously communicate user data through one base station 200 (i.e., the number of data communication paths that can be formed simultaneously). That is, there is an upper limit value for the total number of communication users. In this embodiment, it is assumed that the total number of communication users is limited to half or less of the total number of present users (i.e., p ≤ 1 / 2). At this time, the entropy defined by the above equation (1) is monotonically increasing with respect to p.

[0026] The bandwidth setting unit 366 of the communication control device 360 is configured to determine an appropriate communication bandwidth of the base station 200 based on the entropy calculated by the entropy calculation unit 364, and set the determined communication bandwidth to the router 340 and / or the UPF 350. For example, the appropriate communication bandwidth of the base station 200 may be calculated from the maximum communication capacity (e.g., 1 Gbps) of the base station 200 and the entropy using the following equation. Communication bandwidth = maximum communication capacity × entropy ……(2)

[0027] The router 340 and / or the UPF 350 allocate communication resources for the base station 200 according to the settings from the bandwidth setting unit 366, and operate to relay user data to or from the base station 200 using the communication resources. Thereby, it is possible to efficiently utilize communication resources according to the number of user terminals 100 that are currently communicating user data among the user terminals 100 located in the communication area of the base station 200.

[0028] Figure 3 is a flowchart showing an example of the operation of the communication control device 360 according to an embodiment of the present invention. In step 302, the communication unit 362 of the communication control device 360 acquires the total number of users present in the base station 200 and the total number of its communication users from the UDR 330 at a predetermined time interval over a predetermined period. For example, the communication unit 362 can collect the total number of users present in the base station 200 and the total number of communication users over an arbitrary period such as one day, one week, or one month at an arbitrary time interval such as every 5 minutes, every 15 minutes, or every hour.

[0029] In step 304, the entropy calculation unit 364 calculates the entropy using the above formula (1) for each time when the total number of users present and the total number of communication users are acquired. Thereby, the entropy values at each of a plurality of times during a predetermined period (for example, one day, one week, one month, etc.) can be obtained.

[0030] In step 306, the entropy calculation unit 364 calculates the average value of the obtained plurality of entropy values. For example, the average value of entropy over a predetermined period such as a certain day, a certain week, or a certain month can be obtained.

[0031] In step 308, the bandwidth setting unit 366 sets the communication bandwidth of the base station 200 according to the following formula based on the average value of the entropy. Communication bandwidth = Maximum communication capacity × Entropy average value ……(2’)

[0032] The setting of the communication band of the base station 200 according to the above formula (2') may be fixedly applied for a predetermined fixed period. For example, the communication band calculated by the above formula from the average value of entropy for a certain day may be continuously set for the base station 200 for the next day. Similarly, the communication band for each day may be updated with the communication band based on the entropy average value of the previous day on a daily basis.

[0033] FIG. 4 is a flowchart showing another example of the operation of the communication control device 360 according to an embodiment of the present invention. This example enables dynamic control of the communication band of the base station 200 by estimating entropy using the maximum likelihood estimation method or the least squares method. In the flowchart of FIG. 4, steps 402 and 404 are the same as steps 302 and 304 in the flowchart of FIG. 3 described above, and duplicate explanations are omitted.

[0034] In step 406, the entropy calculation unit 364 determines a function f(x) that approximates the temporal change of these multiple entropy values based on the entropy at each time obtained in step 404. Here, the time is x i (i = 1, 2,..., N), and the entropy calculated by the above formula (1) is denoted as E i . The entropy calculation unit 364 determines the function f(x) of the following formula so as to approximate the time series data (x i , E i ) well. Here, M is an appropriate number representing the highest degree of the polynomial.

[0035]

Equation

[0036] Specifically, the coefficient w i of each degree of the polynomial function f(x) can be calculated as follows according to the maximum likelihood estimation method or the least squares method.

[0037]

Equation

[0038] Also, for time series data (x i , E i ), the variance σ 2 is calculated as follows.

[0039]

Equation

[0040] Next, in step 408, the entropy calculation unit 364 estimates the entropy value at a desired time based on the approximate function f(x) obtained in step 406 and its probability. For example, using the time series data (x i , E i ) for a certain day (or a certain week, a certain month, etc.), the function f(x) determined in step 406 above can be used to estimate the entropy value at any desired time in the next day (or one week, one month, etc.). Specifically, the probability P(E|x k ) that the entropy takes the value E at a certain desired time x k , σ 2 ) follows the following normal distribution.

[0041]

Equation

[0042] Therefore, the entropy calculation unit 364 determines the value E for which the above probability P(E|x k , σ 2 ) is maximized as the estimated entropy value at the desired time x k . For example, by sequentially substituting the value E that increases in a predetermined step width into the above equation (7), the E for which the probability P is maximized can be adopted as the estimated entropy value. Alternatively, since equation (7) reaches its maximum value when E = f(x k ), by calculating the value of f(x k ) (that is, substituting x = x into the function f(x) determined in step 406)k The estimated value of entropy may be obtained by substituting

[0043] Next, in step 410, the bandwidth setting unit 366 sets the communication bandwidth of the base station 200 according to the following formula based on the estimated value of entropy obtained in step 408. Communication Bandwidth = Maximum Communication Capacity × Entropy Estimated Value...(2”)

[0044] The setting of the communication bandwidth of the base station 200 by the above formula (2”) is sequentially and repeatedly performed for any desired time x 1 , x 2 , …, x N . Thereby, the communication bandwidth of the base station 200 can be dynamically controlled. Further, steps 402 to 406 may be repeated every predetermined period (for example, every day, every week, every month, etc.). Thereby, the approximate function f(x) of entropy is updated using the latest data (total number of in-area users and total number of communication users), and the setting of the communication bandwidth of the base station 200 by the above formula (2”) can be accurately performed.

[0045] As described above, the embodiments of the present invention have been described, but the present invention is not limited thereto, and various changes can be made without departing from the gist thereof.

Explanation of Reference Numerals

[0046] 10 Mobile Communication System 100 User Terminals 200 Base Stations 300 Core Network 310 AMF 320 UDM 330 UDR 340 Router 350 UPF 360 Communication Control Device 362 Communication Unit 364 Entropy Calculation Unit 366 Bandwidth Setting Unit 500 External Network

Claims

1. A communication control method in a mobile communication system, comprising: The mobile communication system includes: A base station; A management device that manages registration information of user terminals located within the communication area of the base station; A relay device that relays communication between the base station and an external network; The communication control method includes: Obtaining the total number of present users of the base station from the management device, where the total number of present users represents the total number of user terminals located within the communication area of the base station; Obtaining the total number of communication users of the base station from the base station, where the total number of communication users represents the total number of user terminals located within the communication area of the base station that are performing user data communication via the relay device; Determining an entropy based on the total number of present users and the total number of communication users; Setting the communication bandwidth of the base station to the relay device based on the entropy; A communication control method including the above steps.

2. The communication control method according to claim 1, wherein the entropy is defined by an expression based on the ratio of the total number of present users to the total number of communication users.

3. When the ratio of the total number of communication users to the total number of present users is p, the entropy is defined by the following expression: Entropy = -p × log ２ p - (1 - p) × log ２ (1 - p) The communication control method according to claim 1.

4. The method further includes calculating an average value of the entropy determined in the determining step over a predetermined period, and the setting step includes setting the communication bandwidth of the base station to the relay device based on the calculated average value of the entropy. The communication control method according to claim 1.

5. The method further includes calculating an estimated value of the entropy using the maximum likelihood method or the least squares method based on a plurality of entropies determined in the determining step over a predetermined period, and the setting step includes setting the communication bandwidth of the base station to the relay device based on the estimated value of the entropy. The communication control method according to claim 1.

6. In the setting step, the communication bandwidth of the base station is set to the product of the maximum communication capacity of the base station and the entropy. The communication control method according to any one of claims 1 to 5.

7. A communication control device in a mobile communication system, wherein The mobile communication system includes: The mobile communication system includes: ​ A base station, a management device that manages registration information of user terminals located within the communication area of the base station, a relay device that relays communication between the base station and an external network, and is provided with, and the communication control device is a communication unit that acquires the total number of present users of the base station from the management device and acquires the total number of communication users of the base station from the base station, where the total number of present users represents the total number of user terminals located within the communication area of the base station, and the total number of communication users represents the total number of user terminals among the user terminals located within the communication area of the base station that are performing user data communication via the relay device, an entropy calculation unit that calculates entropy based on the total number of present users and the total number of communication users, a bandwidth setting unit that sets the communication bandwidth of the base station to the relay device based on the entropy, and is provided with, a communication control device.

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