Network management device and network management method

Abstract

This reception unit receives a designation of geographical coordinates of a first location and a second location. A determination unit searches for a plurality of base stations located within a first distance from a line segment connecting the first location and the second location to each other and determines to which group of a plurality of groups each of the plurality of base stations belongs by solving an objective function aimed at minimizing the number of terminals moving between base stations belonging to different groups. An output control unit outputs affiliation information relating to base stations belonging to each of the plurality of groups.

Description

Network management device and network management method

[0001] The present invention relates to a network management device and a network management method.

[0002] Conventionally, communication terminals have been called (paging) using tracking areas (TAs) and tracking area lists (TA-Lists). For example, Patent Document 1 below enables the provision of a tracking area list to a communication terminal according to its movement characteristics. Area number acquisition means refers to history information storage means and acquires the number of tracking areas in which the terminal was present within a predetermined time. Determination means determines whether the acquired number of tracking areas is equal to or greater than a threshold. If the list generation means determines that the number of tracking areas is less than or equal to the threshold, it generates a first tracking area list based on the tracking areas stored in the history information storage means. If the transmission means determines that the number of tracking areas is less than or equal to the threshold, it transmits the first tracking area list to the terminal. If the transmission means determines that the number of tracking areas is greater than the threshold, it transmits a second tracking area list to the terminal.

[0003] Japanese Patent Publication No. 2022-003719

[0004] When a user utilizes a mobile device with a fixed route, such as a train, it is preferable to group base stations located around the mobile device's route into the same group (tracking area and tracking area list). However, manually selecting base stations located around a mobile device's route and grouping them into the same group is extremely time-consuming and difficult to consider factors other than distance from the route.

[0005] The present invention aims to efficiently group base stations around a predetermined route.

[0006] A network management device according to one aspect of the present invention includes: a reception unit that receives the geographical coordinates of a first point and a second point; a determination unit that searches for a plurality of base stations located within a first distance from a line segment connecting the first point and the second point, and determines which of a plurality of groups each of the plurality of base stations belongs to by solving an objective function aimed at minimizing the number of terminals moving between base stations belonging to different groups; and an output control unit that outputs membership information relating to the base stations belonging to each of the plurality of groups.

[0007] A network management method according to one aspect of the present invention is performed by a computer, receives the specification of geographical coordinates of a first point and a second point, searches for a plurality of base stations located within a first distance from a line segment connecting the first point and the second point, and solves an objective function aimed at minimizing the number of terminals moving between base stations belonging to different groups, thereby determining which of a plurality of groups each of the plurality of base stations belongs to, and outputs membership information for the base stations belonging to each of the plurality of groups.

[0008] This invention enables the efficient grouping of base stations around a predetermined route.

[0009] This is a schematic diagram showing the communication system 1 managed by the network management device 10 according to the embodiment. This is a schematic diagram showing the paging method in the communication system 1. This is a schematic diagram showing the paging method in the communication system 1. This is a schematic diagram showing the paging method in the communication system 1. This is a schematic diagram showing the location registration signal RS. This is a block diagram showing the configuration of the network management device 10. This is a schematic diagram showing an example of the display of map MP. This is a schematic diagram showing an example of the display of map MP. This is a schematic diagram showing an example of the display of map MP. This is a schematic diagram showing an example of the display of map MP. This is a schematic diagram showing an example of the display of map MP. This is a schematic diagram showing an example of the display of map MP. This is a diagram showing an example of table TB. This is a diagram showing an example of table TB. This is a flowchart showing the operation of the processing device 105.

[0010] [Embodiment] [Overall Configuration] Figure 1 is a schematic diagram showing a communication system 1 managed by a network management device 10 according to an embodiment. The communication system 1 is a wireless communication system using, for example, LTE (Long Term Evolution). The communication system 1 includes a communication terminal 20, an MME (Mobility Management Entity) 30, and a plurality of base stations S (S1 to S5 are shown in Figure 1).

[0011] The communication terminal 20 is a mobile terminal such as a smartphone, an in-vehicle device, or an IoT (Internet of Things) device. The communication terminal 20 may also be referred to as User Equipment (UE).

[0012] Base station S constitutes a Radio Access Network (RAN) within the communication system 1, which performs wireless communication with communication terminals 20. Base station S may also be referred to as eNB (evolved Node B). The base stations S (S1 to S5) shown in Figure 1 communicate wirelessly with communication terminals 20 located within their respective communication areas E (E1 to E5), called cells. In a RAN, the communication areas E of numerous base stations S form the communication area of ​​the network. In this embodiment, only a few base stations S are shown, but in reality, hundreds to thousands of base stations S are deployed in the communication system 1.

[0013] MME30 is a node that constitutes the control plane (C-plane) of the core network (CN) of communication system 1. MME30 and each base station S are connected by a line called a backhaul. In Figure 1, the connection between MME30 and each base station S is not shown. MME30 performs various controls in communication system 1, such as registering communication terminals 20 in the core network and managing the movement of communication terminals 20.

[0014] Figures 2 to 4 are schematic diagrams showing the paging method in communication system 1. The upper part of Figures 2 to 4 schematically shows the communication areas E1 to E9 of base stations S1 to S9. As shown by the dotted line, it is assumed that the communication terminal 20 was located in the communication area E5 of base station S5 when the previous incoming call ended (end of call). In other words, the base station S that the communication terminal 20 last accessed was base station S5. On the other hand, as shown by the solid line, it is assumed that the communication terminal 20 is currently located in the communication area E1 of base station S1.

[0015] The lower section of Figures 2 to 4 schematically shows the tracking area TA to which base stations S1 to S9 belong. In the example shown, tracking area list TL1 (indicated as "TL1" in the figure) includes tracking areas TA1 to TA3. Tracking area TA1 accommodates base stations S1 to S3. In other words, base stations S1 to S3 belong to tracking area TA1. Base stations S1 to S3 belong to tracking area list TL1. Furthermore, tracking area TA2 accommodates base stations S4 to S6. Tracking area TA3 accommodates base stations S7 to S9.

[0016] Here, we consider the case where there is an incoming call request to the communication terminal 20. An incoming call request includes, for example, the reception of a message using a messaging application, and push notifications from SNS (Social Networking Service) applications, etc. When there is an incoming call request to the communication terminal 20, the MME 30 first causes the base station S5 that the communication terminal 20 last accessed to transmit a paging signal (see Figure 2). Hereinafter, the transmission of the paging signal by the base station S that the communication terminal 20 last accessed will be referred to as "first paging," and the paging signal transmitted in the first paging will be referred to as "first paging signal." "First paging" may also be referred to as "initial paging (first paging)." "First paging signal" may also be referred to as "initial paging signal." In the example shown in Figure 2, the communication terminal 20 is not located in the communication area E5 of base station S5, so the incoming call request via the first paging signal fails.

[0017] If the incoming call request using the first paging signal fails, the MME 30 causes all base stations S belonging to the tracking area TA to which base station S5 (the base station S that transmitted the first paging signal) belongs to transmit paging signals (see Figure 3). Hereinafter, the transmission of paging signals from all base stations S in the tracking area TA to which base station S that transmitted the first paging signal belongs will be called "second paging," and the paging signal transmitted in second paging will be called the "second paging signal." "Second paging" may also be referred to as "retransmission paging." "Second paging signal" may also be referred to as "retransmission paging signal." In the example shown in Figure 3, base station S5 belongs to tracking area TA2. Therefore, the second paging signal is transmitted to the communication areas E4 to E6 of base stations S4 to S6. In the example shown in Figure 3, the communication terminal 20 is not located in the communication areas E4 to E6 of base stations S4 to S6, so the incoming call request using the second paging signal fails.

[0018] If the incoming call request using the second paging signal fails, the MME 30 causes all base stations S in the tracking area list TL that includes tracking area TA2 (the tracking area TA that transmitted the second paging signal) to transmit paging signals (see Figure 4). Hereinafter, the transmission of paging signals from all base stations S in the tracking area list TL that includes the tracking area TA that transmitted the second paging signal will be referred to as "third paging," and the paging signal transmitted in third paging will be referred to as "third paging signal." "Third paging" may also be referred to as "re-retransmission paging." "Third paging signal" may also be referred to as "re-retransmission paging signal." In the example shown in Figure 4, tracking area TA2 is included in tracking area list TL1. Therefore, the third paging signal is transmitted to communication areas E1 to E9 of base stations S1 to S9 belonging to tracking area list TL1. In the example shown in Figure 4, the communication terminal 20 is located in communication area E1 of base station S1, so the incoming call request is successful with the third paging signal.

[0019] If the incoming call request also fails with the third paging signal, the MME 30 will cause the base stations S in the tracking area list TL1, as well as base stations S belonging to other tracking area lists TLs adjacent to tracking area list TL1 (for example, tracking area list TL2 shown in Figure 5), to transmit paging signals.

[0020] Thus, if the incoming call request at the communication terminal 20 fails, the range of paging signals transmitted expands, increasing the processing load at each base station S. For example, considering the number of paging signals transmitted by base stations S1 to S9, if the incoming call is successful in the first paging, the total number of paging signals transmitted is 1 (the first paging signal from base station S5). If the incoming call is successful in the second paging, the total number of paging signals transmitted is 4 (the first paging signal from base station S5 + the second paging signals from base stations S4 to S6). If the incoming call is successful in the third paging, the total number of paging signals transmitted is 13 (the first paging signal from base station S5 + the second paging signals from base stations S4 to S6 + the third paging signals from base stations S1 to S9).

[0021] Furthermore, as the number of communication terminals 20 in the communication system 1 increases, the number of paging signals transmitted increases, and the processing load at each base station S increases. If the processing load exceeds the processing capacity of base station S, communication failures may occur, and it is desirable to reduce the number of paging signals transmitted throughout the entire communication system 1. One example of a measure to reduce the number of paging signals transmitted is to set the tracking area TA such that even when a communication terminal 20 moves, it is more likely to be located within the same tracking area TA before and after the move.

[0022] Another signal generated by the communication system 1 is the location registration signal RS. The location registration signal RS is transmitted to the MME 30 when the communication terminal 20 moves between communication areas E of base stations S belonging to different tracking area lists TL.

[0023] Figure 5 is a schematic diagram showing the location registration signal RS. In addition to the base stations S1 to S9 belonging to tracking area list TL1 shown in Figure 2, etc., Figure 5 also shows base stations S10 to S14 belonging to tracking area list TL2 (indicated as "TL2" in the figure). Tracking area list TL2 includes tracking areas TA4 to TA5. Tracking area TA4 accommodates base stations S10 to S12. In other words, base stations S10 to S12 belong to tracking area TA4. Also, tracking area TA5 accommodates base stations S13 to S14.

[0024] As shown in Figure 5, when a communication terminal 20 moves from the communication area E9 of base station S9, which belongs to tracking area list TL1, to the communication area E10 of base station S10, which belongs to tracking area list TL2, the communication terminal 20 transmits a location registration signal RS to the MME 30. The location registration signal RS is transmitted to the MME 30 via base station S. Therefore, an increase in the number of location registration signals RS transmitted contributes to an increase in the processing load of base station S.

[0025] One possible strategy for transmitting the location registration signal RS is to increase the number of base stations S belonging to a single tracking area list TL. On the other hand, since the third paging signal is transmitted to all base stations S belonging to a single tracking area list TL, it is expected that the number of paging signals transmitted will increase as the number of base stations S belonging to a single tracking area list TL increases. In other words, there is a trade-off relationship between the number of location registration signals RS transmitted and the number of paging signals transmitted.

[0026] [Network Management Device] Figure 6 is a block diagram showing the configuration of the network management device 10. The network management device 10 is, for example, an information processing terminal owned by a business operator (telecommunications carrier) that manages and operates the communication system 1. The network management device 10 may also be, for example, a quantum computer. Alternatively, the network management device 10 may be a computer that is connected to a quantum computer and capable of having the quantum computer execute specific processes.

[0027] The network management device 10 includes a display device 101, an input device 102, a communication device 103, a storage device 104, a processing device 105, and a bus 120 that connects these devices to each other.

[0028] The display device 101 is a display device that displays information to the outside (for example, various display panels such as a liquid crystal display panel or an organic EL display panel). The input device 102 is an input device that accepts input from the outside (for example, a keyboard, mouse, microphone, switch, button, or sensor). The display device 101 and the input device 102 may be configured as an integrated unit (for example, a touch panel). The communication device 103 has an interface that can connect to a network and communicates with other devices connected to the network using wireless or wired communication.

[0029] The storage device 104 is a recording medium that can be read by the processing device 105. The storage device 104 includes, for example, non-volatile memory and volatile memory. Non-volatile memory includes, for example, ROM (Read Only Memory), EPROM (Erasable Programmable Read Only Memory), and EEPROM (Electrically Erasable Programmable Read Only Memory). Volatile memory includes, for example, RAM (Random Access Memory). The storage device 104 stores program PG1, map data DB1, and base station data DB2.

[0030] The program PG1 is a program for operating the network management device 10. The map data DB1 stores a map (map image) MP including the communication area of the communication system 1. The map data DB1 includes latitude and longitude information that uniquely identifies each point on the map MP. The base station data DB2 stores the position information of each of the plurality of base stations S and the base station identification information for identifying each of the plurality of base stations S in association with each other. In the present embodiment, the position information of the base station S is latitude information and longitude information. By combining the map data DB1 and the base station data DB2, for example, the location of the base station S can be displayed as a point (or any arbitrary mark) or the like, superimposed on the map MP displayed on the display device 101.

[0031] The processing device 105 includes one or a plurality of CPUs (Central Processing Units). The one or more CPUs are an example of one or more processors. Each of the processor and the CPU is an example of a computer. The processing device 105 reads the program PG1 from the storage device 104. By executing the program PG1, the processing device 105 functions as a reception unit 111, a determination unit 112, and an output control unit 113.

[0032] At least a part of the reception unit 111, the determination unit 112, and the output control unit 113 may be configured by a circuit such as a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), and an FPGA (Field Programmable Gate Array).

[0033] The reception unit 111 receives designation of geographical coordinates of a first point and a second point. The first point and the second point may be rephrased as a plurality of points. The geographical coordinates are, for example, latitude and longitude. The reception unit 111 displays, for example, a map MP on the display device 101, and receives designation of a first point P and a second point P on the map MP, thereby receiving designation of the geographical coordinates of the first point and the second point. The first point P and the second point P may be rephrased as a plurality of points P. Further, the reception unit 111 may receive input of values of latitude and longitude (geographical coordinates) of the first point and the second point using a keyboard or the like, for example.

[0034] Further, the reception unit 111 receives, for example, drawing of a circle C having one of the first point P and the second point P as a center point O. A determination unit 112 described later uses a radius R of the circle C as a first distance D1 described later. The reception unit 111 displays, for example, the map MP on the display device 101, and receives designation of at least two points P (including the first point P and the second point P) from the user of the network management device 10 via the input device 102. Further, the reception unit 111 displays a circle C centered on any point P, and receives designation of the radius R of the circle C from the user. The user is, for example, an administrator of the communication system 1 (or a worker who has received an instruction from the administrator).

[0035] The determination unit 112 searches for a plurality of base stations S located within a first distance D1 (within a search area SA described later) from a line segment LS connecting the first point and the second point to each other, and solves an objective function aimed at minimizing the number of communication terminals 20 moving between base stations S belonging to different groups GP, thereby determining which of the plurality of groups GP each of the plurality of base stations S belongs to. The communication terminal 20 is an example of a terminal. The plurality of base stations S searched by the determination unit 112 are referred to as "searched base stations SK". The searched base stations SK are the base stations S located within the search area SA.

[0036] In this embodiment, multiple group GPs are multiple tracking area lists TLs. Therefore, the objective function is one that aims to minimize the number of location registration signals RS transmitted when the communication terminal 20 moves between base stations S belonging to different tracking area lists TLs. Details of the objective function will be described later.

[0037] The output control unit 113 outputs membership information for each of the multiple group GPs that the base stations S belong to. Membership information is, for example, information that can identify which of the multiple group GPs each of the multiple base stations S belongs to. In other words, membership information is, for example, information that can identify which of the multiple base stations S belong to each of the multiple group GPs.

[0038] The output control unit 113 displays multiple marks on the map MP that indicate the locations of multiple search base stations SK, for example, that have been searched by the determination unit 112. As membership information, the output control unit 113 displays images with the same image processing applied to the marks corresponding to base stations S that belong to the same group GP among the multiple marks. The same image processing may include, for example, displaying the marks of base stations S belonging to the same group GP in the same color, or displaying a line segment surrounding the marks of base stations S belonging to the same group GP.

[0039] Alternatively, the output control unit 113 may output a table (for example, table TB2 shown in Figure 8B) that associates the identification information of multiple group GPs with the identification information of the base stations S belonging to each of the multiple group GPs.

[0040] Figures 7A to 7G are schematic diagrams showing an example of the display of map MP. In Figure 7A, the display device 101 displays map MP. Map MP displays the shape of roads, railway lines, etc., in real space. Operation buttons BT1 to BT4 are also displayed on the display device 101. Operation button BT1 is a button for specifying a point P on map MP. When the user presses operation button BT1, the display color of operation button BT1 changes as shown in Figure 7B. This is to make it easier for the user to understand that operation button BT1 is selected. The reception unit 111 waits for the location of point P to be specified. In this state, when the user performs an operation such as tapping or clicking on any location on map MP, point P is displayed at that location. In this embodiment, multiple points P1 to P4 are specified along route LT, which is one of the railway lines. Point P1 is an example of the first point P, and point P4 is an example of the second point P. The first point P may be the starting point of the line segment, and the second point P may be the ending point of the line segment. Generally, a "point" does not have size, but in this embodiment, point P (especially point P displayed on map MP) has a certain size.

[0041] Furthermore, each time a point P is specified, a line segment is drawn between that point P and the point P specified immediately before it. As a result, in Figure 7B, the line segment LS connecting points P1 to P4 is displayed on the map MP. Since the user has specified points P1 to P4 along the route LT, the line segment LS is roughly aligned with the route LT.

[0042] The operation button BT2 is used to specify the first distance D1. When the user presses the operation button BT2, the display color of the operation button BT2 changes as shown in Figure 7C. The reception unit 111 also waits for the first distance D1 to be specified. In this state, if the user performs a selection operation such as tapping or clicking on any point P, the outer edge of point P becomes movable. By moving the outer edge of point P, point P becomes a circle C. In the example in Figure 7C, the outer edge of point P3 is moved, and a circle C with point P3 as the center point O is drawn. The reception unit 111 accepts the radius R of circle C as the first distance D1. Once the first distance D1 is specified, the search area SA of base station S is determined. Figure 7D shows the search area SA. The search area SA is set on both sides of the line segment LS and is the range of the first distance D1 perpendicular to the line segment LS. In other words, the search area SA is a strip-shaped region with a width of D1 × 2 that extends along the line segment LS.

[0043] The operation button BT3 is used to instruct the system to search for base stations S (search base stations SK) within the search area SA. When the user presses the operation button BT3, the determination unit 112 uses the base station data DB2 to search for base stations S whose location information is included in the search area SA, and identifies them as search base stations SK. The output control unit 113 displays the location of the search base stations SK found by the determination unit 112 on the map MP. Figure 7E shows an example of the display of search base stations SK. In Figure 7E, marks (icons) representing multiple search base stations SK are displayed at the location of each search base station SK. Note that in Figure 7E, for illustrative purposes, several search base stations SK are shown around each point P, but in reality, several dozen search base stations SK may be found. According to the display example in Figure 7E, the user can easily grasp the location of each search base station SK.

[0044] Figure 7F shows another example of how to display search base stations SK. In Figure 7F, icons HK (HK1 to HK4) indicating the number of search base stations SK located around points P1 to P4 are displayed at positions corresponding to points P1 to P4 on the map MP. For example, of the search base stations SK, there are 35 search base stations SK that are closest to point P1, and 22 search base stations SK that are closest to point P2. The size of icons HK1 to HK4 is drawn in proportion to the number of search base stations SK. According to the display example in Figure 7F, users can easily grasp the number of search base stations SK located near each point P.

[0045] Alternatively, instead of displaying the search base stations SK on the map MP, they may be displayed using a table TB (TL1, etc.). Figure 8A shows an example of a table TB. The table TB1 shown in Figure 8A includes base station identification information 801 (indicated as "base station ID" in the figure), latitude information 802, and longitude information 803 for the search base stations SK. The table TB1 may also include, for example, identification information (point P1, etc.) for the point closest to each search base station SK. According to the display example in Figure 8A, the user can easily grasp the number of search base stations SK within the search area SA.

[0046] Returning to the explanation of Figure 7F, the operation button BT4 is a button for instructing the grouping of search base stations SK. When the user presses the operation button BT4, the determination unit 112 groups the search base stations SK to create multiple group GPs (for example, GP1 to GP3). As described above, in this embodiment, a group GP is a tracking area list TL. The grouping of search base stations SK can be rephrased as the optimization of the tracking area list TL to which the search base stations SK belong. The output control unit 113 displays the affiliation information indicating the group GPs created by the determination unit 112 on the map MP.

[0047] Figure 7G shows an example of how affiliation information is displayed. In Figure 7G, the marks of search base stations SK belonging to the same group GP are enclosed by a single closed line (a dotted line in the example of Figure 7G). In other words, Figure 7G is an example of displaying an image in which the marks corresponding to search base stations SK belonging to the same group GP are enclosed by the same line as affiliation information. In the example of Figure 7G, the search base stations SK are grouped into three groups GP1 to GP3. According to the display example in Figure 7G, the user can easily grasp the location of each group GP and the distribution of base stations S within each group GP.

[0048] The example in Figure 7G is not the only way to indicate affiliation information; for example, affiliation information may be indicated by displaying the marks of search base stations SK belonging to the same group GP in the same color. More specifically, for example, the marks of search base stations SK belonging to group GP1 may be displayed in red, the marks of search base stations SK belonging to group GP2 in blue, and the marks of search base stations SK belonging to group GP3 in green. Alternatively, for example, the marks of search base stations SK belonging to each group GP may be different. More specifically, for example, search base stations SK belonging to group GP1 may be displayed in a circle, search base stations SK belonging to group GP2 in a square, and search base stations SK belonging to group GP3 in a triangle.

[0049] Alternatively, instead of displaying the affiliation information on the map MP, it may be displayed using a table TB (TL2, etc.). Figure 8B shows an example of a table TB. The table TB2 shown in Figure 8B includes group identification information 811 (indicated as "Group ID" in the figure) that identifies a group GP (e.g., tracking area list TL), and base station identification information 812 (indicated as "Base Station ID" in the figure) of the search base stations SK belonging to the group GP. The table TB2 may also include, for example, the latitude information, longitude information, and identification information (point P1, etc.) of each search base station SK and the point closest to each search base station SK. According to the display example in Figure 8B, the user can easily grasp the number of search base stations SK belonging to each group GP.

[0050] Next, the method for determining the group GP will be explained. Hereafter, "grouping" will be referred to as "optimization". As described above, the determination unit 112 determines which of the multiple group GPs each of the multiple base stations S belongs to by solving an objective function that aims to minimize the number of communication terminals 20 that move between base stations S belonging to different group GPs. A group GP is a tracking area list TL to which each of the multiple search base stations SK belongs. Therefore, the objective function is an objective function that aims to minimize the number of location registration signals RS transmitted when a communication terminal 20 moves between base stations S belonging to different tracking area lists TLs. Hereafter, "minimizing the number of location registration signals RS transmitted" may be written as "minimizing the number of location registration signals RS".

[0051] The decision unit 112 finds a solution to the objective function, for example, using quantum annealing. Quantum annealing is known to quickly find good solutions in combinatorial optimization problems. Quantum annealing is performed in the following steps: [1] conversion of the objective function to QUBO (Quadratic Unconstrained Binary Optimization) form, [2] mapping to the circuit, and [3] execution of quantum annealing. If the network management device 10 is a quantum computer, the decision unit 112 may perform steps [1] to [3] above. Alternatively, if the network management device 10 is a computer connected to a quantum computer, the decision unit 112 may request the quantum computer to perform step [3] to obtain a solution to the objective function.

[0052] Let e ​​be an integer greater than or equal to 1, among the base stations S in the communication system 1, to be the target of this optimization. Let A = {a, b, ...} be the number of tracking area lists TL to be optimized, where a, b, etc., represent individual tracking area lists TL. The tracking area list TL indicated by a is called the "a-th tracking area list TL". The tracking area list TL indicated by b is called the "b-th tracking area list TL". The number of tracking area lists TL to be optimized is denoted as |A|. The number of tracking areas in each tracking area list TL is denoted as |a|, |b|, .... The number of tracking areas TA in the tracking area list TL to be optimized is f ｓｕｍ It can be shown that (= |a| + |b| + ...).

[0053] The belonging of each of the e base stations S to the tracking area list TL and tracking area TA is shown by the matrix X in the following equation (1). The matrix X is e row f ｓｕｍ It is a matrix of columns. In equation (1) below, for the sake of simplicity, we assume that the targets of optimization are two tracking area list TLs, a-th tracking area list TL and b-th tracking area list TL. The elements (components) of matrix X are, for example, x ａ ｉ，ｊ It is written as x ａ ｉ，ｊ This indicates a flag = {1, 0} that shows whether the i-th base station S belongs to the j-th tracking area TA of the a-th tracking area list TL. Since each base station S belongs to only one tracking area list TL and tracking area TA, the sum of the horizontal (row) values ​​of matrix X is constrained to 1, as shown in equation (2) below.

[0054]

[0055] The matrix X' shown in equation (3) below is an e-row |A| matrix indicating which tracking area list TL each base station S belongs to. Equation (3) below shows the case where |A| = 2, similar to equation (1) above. The elements of matrix X' are, for example, x' ａｉ is denoted as. x' ａ ｉ represents a flag = {1, 0} indicating whether the i-th base station S belongs to the a-th tracking area list TL. As shown in the following formula (4), x' ａ ｉ is the number of base stations S belonging to the a-th tracking area list TL.

[0056]

[0057] The total number G of location registration signals RS generated Ｌ is represented by the following formula (8). Parameters related to G Ｌ are represented by the following formulas (5) to (7). The movement model M shown in formula (5) Ｌ is a movement model of the communication terminal 20 generated for simulation of the location registration signal RS. The movement model M Ｌ is generated using statistical values indicating the hourly movement status of the communication terminal 20. The movement model M Ｌ is an e-row e-column matrix as shown in the following formula (5). Therefore, the movement model M Ｌ may also be referred to as a movement matrix. The elements (components) of the movement model M Ｌ are denoted as m Ｌ ｋ，ｉ . k and i are integers from 1 to e. m Ｌ ｋ，ｉ is the total number of communication terminals 20 that have moved from the communication area E of the k-th base station S to the i-th base station S.

[0058] R shown in formula (6) Ｌ is an e-row e-column matrix indicating whether each pair of base stations S belongs to different tracking area lists TL. The r shown in the following formula (7) Ｌ ｋ，ｉ is a flag indicating whether the k-th base station S and the i-th base station S belong to different tracking area lists TL. More specifically, it takes 1 when the k-th base station S and the i-th base station S belong to different tracking area lists TL, and takes 0 when the k-th base station S and the i-th base station S belong to the same tracking area list TL. GＬ The solution that minimizes (X' or X) is the solution that satisfies the "minimization of the position registration signal RS". In other words, the objective function that aims to minimize the number of communication terminals 20 moving between base stations S belonging to different groups GP is, for example, the G shown in equation (8) below. Ｌ That is the case.

[0059]

[0060] [Flowchart] Figure 9 is a flowchart showing the operation of the processing unit 105. The processing unit 105 functions as a reception unit 111 and displays the map MP on the display device 101 (step S100). When the operation button BT1 is operated, the processing unit 105 functions as a reception unit 111 and accepts the specification of a point P on the map MP (step S102). Each time a point P is specified, the reception unit 111 draws a line segment LS connecting the points P on the map MP.

[0061] When the operation button BT2 is operated, the processing unit 105 functions as a reception unit 111 and accepts the specification of the first distance D1 (step S104). The specification of the first distance D1 is done by specifying the radius R of any point P. The search area SA is specified by the line segment LS and the first distance D1.

[0062] When the operation button BT3 is pressed, the processing unit 105 functions as a determination unit 112 and searches for a base station S (search base station SK) within the search area SA (step S106). The processing unit 105 functions as an output control unit 113 and displays a mark on the map MP at the location of the search base station SK (step S108).

[0063] When the operation button BT4 is operated, the processing unit 105 functions as a determination unit 112 and determines which of the multiple group GPs each search base station SK belongs to (step S110). The processing unit 105 functions as an output control unit 113 and outputs affiliation information indicating which of the multiple group GPs each search base station SK belongs to (step S112), and the processing of this flowchart ends.

[0064] [Summary of Embodiments] As described above, the network management device 10 according to the embodiment receives a route (line segment LS) and a first distance D1 from the route from the user, sets a search area SA along the route, and searches for base stations S located in the search area SA. Therefore, the user can efficiently search for base stations S located around a predetermined route. Furthermore, the network management device 10 has an objective function G that aims to minimize the number of communication terminals 20 moving between base stations S belonging to different groups GP. Ｌ By solving this equation, it is determined which group GP each base station S belongs to. Therefore, the period during which a communication terminal 20 traveling along a route is located within the communication area of ​​multiple base stations S belonging to the same group GP can be extended, thereby improving communication quality.

[0065] Furthermore, the network management device 10 accepts the designation of multiple points P on a map MP representing the real world, thereby accepting the designation of multiple locations (routes). Therefore, the user can easily specify a desired route, such as a specific railway line. The network management device 10 also uses the radius R of a circle C with one of the multiple points P as its center point O as the first distance D1. Therefore, the user can easily and intuitively specify the range of the search area SA.

[0066] Furthermore, the network management device 10 displays, as membership information, images that have undergone the same image processing on marks corresponding to search base stations SK belonging to the same group GP from among multiple marks indicating search base stations SK. Therefore, users can easily grasp the geographical arrangement of base stations S belonging to the same group GP. In addition, the network management device 10 outputs a table TB2 as membership information, which associates the identification information of multiple group GPs with the identification information of base stations S belonging to each of the multiple group GPs. Therefore, users can easily grasp the number of base stations S belonging to each of the multiple group GPs.

[0067] [Modification] In this embodiment, the network management device 10 (determination unit 112) determines which of the multiple group GPs each of the multiple base stations S belongs to. However, the user may also determine which of the multiple group GPs each of the multiple base stations S belongs to. In this case, the network management device 10 executes steps S100 to S108 of the flowchart in Figure 9, for example. When a mark is displayed at the location of the search base station SK on the map MP in step S108, the user specifies the group GP to which each of the search base stations SK belongs. The interface for group specification is arbitrary.

[0068] For example, the user is first asked to specify the number of Group GPs. Next, the user is asked to specify the search base station SK to belong to the first Group GP. The user specifies the search base station SK to belong to the first Group GP by tapping or clicking on a mark on the map MP. Alternatively, the user can specify an area on the map MP and specify that the search base station SK located within that area should belong to the first Group GP. The above process is repeated for the number of Group GPs specified by the user.

[0069] According to the modified version, the user can efficiently search for base stations S located around a predetermined route. Furthermore, the user can freely determine the group GP to which the base stations S within the search area SA belong, enabling the realization of network configurations suitable for various situations.

[0070] [Other] (1) In the embodiments described above, ROM and RAM were given as examples of the storage device 104, but the storage device 104 may be a flexible disk, magneto-optical disk (e.g., compact disk, digital multipurpose disk, Blu-ray® disk), smart card, flash memory device (e.g., card, stick, key drive), CD-ROM (Compact Disc-ROM), register, removable disk, hard disk, floppy® disk, magnetic strip, database, server, or other suitable storage medium.

[0071] (2) In the embodiments described above, the information, signals, etc. may be represented using any of the various different techniques. For example, the data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0072] (3) In the embodiments described above, the input and output information may be stored in a specific location (e.g., memory) or managed using a management table. The input and output information may be overwritten, updated, or appended to. The output information may be deleted. The input information may be transmitted to other devices.

[0073] (4) In the embodiments described above, the determination may be made by a value represented by one bit (0 or 1), by a Boolean value (true or false), or by a numerical comparison (for example, a comparison with a predetermined value).

[0074] (5) The processing procedures, sequences, flowcharts, etc., exemplified in the embodiments described above may be rearranged in order, as long as there is no inconsistency. For example, in the methods described herein, various step elements are presented using an exemplary order and are not limited to the specific order presented.

[0075] (6) Each function illustrated in Figure 6 is implemented by any combination of at least one of hardware and software. Furthermore, the method of implementing each function block is not particularly limited. That is, each function block may be implemented using one device that is physically or logically coupled, or it may be implemented using two or more physically or logically separated devices that are directly or indirectly connected (for example, using wired, wireless, etc.). A function block may also be implemented by combining the one or more devices with software.

[0076] (7) The programs illustrated in the embodiments described above should be broadly interpreted to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, etc., whether they are called software, firmware, middleware, microcode, hardware description languages ​​or by any other name.

[0077] Furthermore, software, instructions, information, etc., may be transmitted and received via a transmission medium. For example, if software is transmitted from a website, server, or other remote source using at least one of wired technology (such as coaxial cable, fiber optic cable, twisted pair, or digital subscriber line (DSL)) and wireless technology (such as infrared or microwave), then at least one of these wired and wireless technologies is included in the definition of a transmission medium.

[0078] (8) In each of the above-mentioned forms, the terms “system” and “network” shall be used interchangeably.

[0079] (9) The information, parameters, etc. described in this disclosure may be expressed using absolute values, relative values ​​from a given value, or other corresponding information.

[0080] (10) In the embodiments described above, the portable device may be a Mobile Station (MS). A Mobile Station may also be referred to by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or several other appropriate terms. In this disclosure, terms such as “mobile station,” “user terminal,” “user equipment (UE),” and “terminal” may be used interchangeably.

[0081] (11) In the embodiments described above, the terms “connected,” “coupled,” or any variation thereof means any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are “connected” or “coupled” with each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, “connection” may be read as “access.” As used in the present disclosure, two elements may be considered to be “connected” or “coupled” with each other using at least one of one or more wires, cables, and printed electrical connections, and, in some non-limiting and non-exclusive examples, electromagnetic energy having wavelengths in the radio frequency domain, microwave domain, and optical (both visible and invisible) domain.

[0082] (12) In the embodiments described above, the phrase "based on" does not mean "based solely on" unless otherwise specified. In other words, the phrase "based on" means both "based solely on" and "based at least on".

[0083] (13) The terms “determinating” and “deciding” as used in this disclosure may encompass a wide variety of actions. “Determinating” and “deciding” may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, search, inquiry (for example, searching in a table, database or other data structure), and confirming. Furthermore, "judgment" and "decision" may include considering something as a "judgment" or "decision" based on actions such as receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, and access (e.g., accessing data in memory). Additionally, "judgment" and "decision" may include considering something as a "judgment" or "decision" based on actions such as resolving, selecting, choosing, establishing, and comparing. In short, "judgment" and "decision" may include considering something as a "judgment" or "decision" based on some action. Furthermore, "judgment (decision)" may be reinterpreted as "assuming," "expecting," or "considering."

[0084] (14) Where the terms “include,” “including,” and variations thereof are used in the embodiments described above, these terms are intended to be inclusive, as is the term “comprising.” Furthermore, the term “or” as used in this disclosure is not intended to be exclusive OR.

[0085] (15) In the present disclosure, if articles are added by translation, for example, a, an, and the in English, the present disclosure may include the fact that the noun following these articles is plural.

[0086] (16) In this disclosure, the term “A and B are different” may mean “A and B are different from each other.” The term may also mean “A and B are each different from C.” Terms such as “separate” and “combine” may be interpreted in the same way as “different.”

[0087] (17) Each aspect / embodiment described herein may be used individually, in combination, or switched between as needed during implementation. Furthermore, notification of certain information (e.g., notification that "it is X") is not limited to explicit notification, but may also be implicit (e.g., by not providing such notification).

[0088] 1...Communication system, 10...Network management device, 20...Communication terminal, 101...Display device, 102...Input device, 103...Communication device, 104...Storage device, 105...Processing device, 111...Reception unit, 112...Decision unit, 113...Output control unit, S...Base station, SA...Search area, SK...Search base station.

Claims

1. A network management device comprising: a reception unit that accepts the geographical coordinates of a first point and a second point; a determination unit that searches for a plurality of base stations located within a first distance from a line segment connecting the first point and the second point, and determines which of a plurality of groups each of the plurality of base stations belongs to by solving an objective function aimed at minimizing the number of terminals moving between base stations belonging to different groups; and an output control unit that outputs membership information relating to the base stations belonging to each of the plurality of groups.

2. The network management device according to claim 1, wherein the receiving unit displays a map on a display device and accepts the designation of a first point and a second point on the map, thereby accepting the designation of the geographic coordinates of the first point and the second point.

3. The network management device according to claim 2, wherein the receiving unit receives an instruction to draw a circle with one of the first point and the second point as its center point, and the determining unit uses the radius of the circle as the first distance.

4. The network management device according to claim 2, wherein the output control unit displays a plurality of marks on the map indicating the locations of the plurality of base stations retrieved by the determination unit, and displays, as the membership information, an image that has undergone the same image processing on the marks corresponding to base stations belonging to the same group among the plurality of marks.

5. The network management device according to claim 2, wherein the output control unit outputs a table as the membership information, which associates the identification information of the plurality of groups with the identification information of the base stations belonging to each of the plurality of groups.

6. The network management device according to claim 1, wherein the plurality of groups are a plurality of tracking area lists.

7. The network management device according to claim 6, wherein the objective function is one that aims to minimize the number of location registration signals transmitted when the terminal moves between base stations belonging to different tracking area lists.

8. A network management method performed by a computer, which accepts the geographical coordinates of a first point and a second point, searches for a plurality of base stations located within a first distance from a line segment connecting the first point and the second point, solves an objective function aimed at minimizing the number of terminals moving between base stations belonging to different groups, determines which of a plurality of groups each of the plurality of base stations belongs to, and outputs membership information for the base stations belonging to each of the plurality of groups.

Images