Processing device and display control method

Abstract

A display control unit 115 controls a display device 101 to display an image. Specifically, the display control unit 115 displays, on the display device 101, a wireless base station graphic which indicates wireless base stations S at the respective positions of the wireless base stations S on a map, and displays, on the display device 101 with respective graphics, information which pertains to the state of a tracking area TA and information which pertains to the state of movement of a communication terminal 20 between the wireless base stations S.

Description

Processing device and display control method

[0001] The present invention relates to a processing device for performing display and a display control method.

[0002] Conventionally, a communication terminal is called (paged) using a tracking area (TA) and a tracking area list (TA-List). For example, the invention described in Patent Document 1 provides a communication terminal with a tracking area list according to its mobility characteristics.

[0003] Japanese Patent Application Laid-Open No. 2022-003719

[0004] In order to reduce the number of paging signals sent when calling a communication terminal, efforts are being made to optimize the tracking area and tracking area list to which a wireless base station belongs. There are various methods for optimizing the tracking area and tracking area list, but it would be convenient if the state of the optimization before and after the process could be visually confirmed.

[0005] Therefore, an object of the present invention is to provide a mechanism that allows visual confirmation of the state in which the tracking area to which a wireless base station belongs and the tracking area list have been optimized.

[0006] In order to solve the above problem, the present invention provides a display device that displays a radio base station figure, which is a graphic indicating each radio base station, at the position of the radio base station on a map, and is characterized by having a display control unit that displays, using graphics, information regarding the state of a tracking area consisting of cells of one or more of the radio base stations and information regarding the state of movement of communication terminals between each of the radio base stations.

[0007] According to the present invention, it is possible to visually confirm how the tracking area to which the radio base station belongs and the tracking area list have been optimized.

[0008] 1 is a schematic diagram showing a communication system 1 managed by a communication management device 10 according to an embodiment. FIG. 1 is a schematic diagram showing a paging method in the communication system 1. FIG. 1 is a schematic diagram showing a paging method in the communication system 1. FIG. 1 is a schematic diagram showing a location registration signal RS. FIG. 1 is a schematic diagram showing an example of first determination information. FIG. 2 is a block diagram showing the configuration of the communication management device 10. FIG. 2 is a diagram showing a schematic relationship between the position of a wireless base station S and a tracking area TA. FIG. 3 is a table showing the belonging of a tracking area TA of a wireless base station S. FIG. 3 is a table showing the belonging of a tracking area TA of a wireless base station S. FIG. 4 is a flowchart showing the operation of a processing device 105 of the communication management device 10. FIG. 4 is a diagram showing an example of an image displayed on a display device 101 of the communication management device 10 before an optimization process. FIG. 5 is a diagram showing an example of an image displayed on a display device 101 of the communication management device 10 after an optimization process. FIG. 6 is a diagram explaining considerations regarding an image displayed on a display device 101 of the communication management device 10 after an optimization process. FIG. 7 is a block diagram showing the configuration of a communication management device 10A according to a first modified example.

[0009] A. Embodiment A-1. Overall Configuration FIG. 1 is a schematic diagram showing a communication system 1 managed by a communication 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 multiple wireless base stations S (S1 to S5 are shown in FIG. 1).

[0010] The communication terminal 20 is a mobile communication device such as a smartphone, an in-vehicle device, a wearable terminal, an IoT (Internet of Things) device, etc. The communication terminal 20 may also be referred to as a user equipment (UE).

[0011] The radio base stations S constitute a radio access network (RAN) in the communication system 1 that performs radio communication with the communication terminals 20. The radio base stations S may also be referred to as eNBs (evolved Node Bs). The radio base stations S (S1 to S5) shown in FIG. 1 wirelessly communicate with the communication terminals 20 located within their respective communication areas A (A1 to A5) called cells. In the RAN, the communication areas A of the many radio base stations S form the communication area of ​​the network. In this embodiment, only a few radio base stations S are shown, but in reality, hundreds to thousands of radio base stations S are deployed in the communication system 1.

[0012] The MME 30 is a node that constitutes a control plane (C-Plane) in the core network (CN) of the communication system 1. The MME 30 and each radio base station S are connected by a line called a backhaul. In FIG. 1 , the connection between the MME 30 and each radio base station S is omitted from the illustration. The MME 30 performs various controls in the communication system 1, such as registering the communication terminal 20 in the core network and managing the mobility of the communication terminal 20.

[0013] 2 to 4 are schematic diagrams illustrating a paging method in communication system 1. The upper parts of FIGS. 2 to 4 schematically illustrate communication areas A1 to A9 of wireless base stations S1 to S9. As shown by the dotted lines, it is assumed that communication terminal 20 was located in communication area A5 of wireless base station S5 when the previous incoming call ended (when the call ended). In other words, the wireless base station S last accessed by communication terminal 20 is wireless base station S5. Meanwhile, as shown by the solid lines, it is assumed that communication terminal 20 is currently located in communication area A1 of wireless base station S1.

[0014] The lower parts of Figures 2 to 4 schematically show tracking areas TA to which wireless base stations S1 to S9 belong. In the example shown in the figures, tracking area list L1 (denoted as "TA-List1" in the figures) includes tracking areas TA1 to TA3. Tracking area TA1 contains wireless base stations S1 to S3. In other words, wireless base stations S1 to S3 belong to tracking area TA1. Furthermore, wireless base stations S1 to S3 belong to tracking area list L1. Furthermore, tracking area TA2 contains wireless base stations S4 to S6. Tracking area TA3 contains wireless base stations S7 to S9.

[0015] Here, a case where an incoming call request is made to the communication terminal 20 will be considered. The incoming call request includes, for example, receiving a message using a message application and a push notification from a social networking service (SNS) application or the like. When an incoming call request is made to the communication terminal 20, the MME 30 first causes a paging signal to be transmitted from the radio base station S5 last accessed by the communication terminal 20 (see FIG. 2 ). Hereinafter, transmission of a paging signal from the radio base station S5 last accessed by the communication terminal 20 will be referred to as a “first paging,” and a paging signal transmitted in the first paging will be referred to as a “first paging signal.” The “first paging” may also be referred to as a “first paging (initial paging).” The “first paging signal” may also be referred to as a “first paging signal.” In the example shown in FIG. 2 , the communication terminal 20 is not located in the communication area A5 of the radio base station S5, so the incoming call request by the first paging signal fails.

[0016] If the call reception request by the first paging signal fails, the MME 30 causes all radio base stations S belonging to the tracking area TA to which the radio base station S5 (the radio base station S that transmitted the first paging signal) belongs to transmit paging signals (see FIG. 3 ). Hereinafter, transmission of paging signals from all radio base stations S in the tracking area TA to which the radio base station S that transmitted the first paging signal belongs will be referred to as "second paging," and the paging signal transmitted in the second paging will be referred to as the "second paging signal." The "second paging" may also be referred to as a "retransmitted paging signal." The "second paging signal" may also be referred to as a "retransmitted paging signal." In the example shown in FIG. 3 , the radio base station S5 belongs to the tracking area TA2. Therefore, the second paging signal is transmitted to the communication areas A4 to A6 of the radio base stations S4 to S6. In the example shown in FIG. 3 , the communication terminal 20 is not located in the communication areas A4 to A6 of the radio base stations S4 to S6, so the call reception request by the second paging signal fails.

[0017] If the call reception request by the second paging signal fails, the MME 30 causes all radio base stations S in the tracking area list L that includes the tracking area TA2 (the tracking area TA that transmitted the second paging signal) to transmit paging signals (see FIG. 4 ). Hereinafter, transmitting paging signals from all radio base stations S in the tracking area list L that includes the tracking area TA that transmitted the second paging signal is referred to as "third paging," and the paging signal transmitted in the third paging is referred to as the "third paging signal." The term "third paging" may also be referred to as "re-resend paging." The term "third paging signal" may also be referred to as "re-resend paging signal." In the example shown in FIG. 4 , the tracking area TA2 is included in the tracking area list L1. Therefore, the third paging signal is transmitted to the communication areas A1 to A9 of the radio base stations S1 to S9 that belong to the tracking area list L1. In the example shown in FIG. 4 , since the communication terminal 20 is located in the communication area A1 of the radio base station S1, the call reception request is successful by the third paging signal.

[0018] In addition, if the incoming call request fails even with the third paging signal, MME 30 causes paging signals to be transmitted not only from the radio base stations S in the tracking area list L1 but also from radio base stations S belonging to other tracking area lists L adjacent to the tracking area list L1 (for example, tracking area list L2 shown in Figure 5).

[0019] In this way, if the call reception request at communication terminal 20 fails, the transmission range of the paging signal expands, and the processing load at each wireless base station S increases. For example, considering the number of paging signal transmissions at wireless base stations S1 to S9, if the call reception is successful at the first paging, the total number of paging signal transmissions is 1 (first paging signal from wireless base station S5). If the call reception is successful at the second paging, the total number of paging signal transmissions is 4 (first paging signal from wireless base station S5 + second paging signals from wireless base stations S4 to S6). If the call reception is successful at the third paging, the total number of paging signal transmissions is 13 (first paging signal from wireless base station S5 + second paging signals from wireless base stations S4 to S6 + third paging signal from wireless base stations S1 to S9).

[0020] Furthermore, the greater the number of communication terminals 20 in the communication system 1, the greater the number of transmitted paging signals, resulting in a larger processing load in each wireless base station S. If the processing load exceeds the processing capacity of the wireless base station S, communication failure may occur, and it is therefore desirable to reduce the number of transmitted paging signals throughout the communication system 1. One example of a measure to reduce the number of transmitted paging signals is to set tracking areas TA so that, even when the communication terminal 20 moves, it is more likely to be located in the same tracking area TA before and after the movement.

[0021] Another signal generated in the communication system 1 is a location registration signal RS. The location registration signal RS is transmitted to the MME 30 when the communication terminal 20 moves between communication areas A of radio base stations S that belong to different tracking area lists L.

[0022] Fig. 5 is a schematic diagram showing a location registration signal RS. In addition to the radio base stations S1 to S9 belonging to the tracking area list L1 shown in Fig. 2 etc., Fig. 5 also shows radio base stations S10 to S14 belonging to a tracking area list L2 (denoted as "TA-List2" in the figure). The tracking area list L2 includes tracking areas TA4 to TA5. The tracking area TA4 contains the radio base stations S10 to S12. In other words, the radio base stations S10 to S12 belong to the tracking area TA4. Furthermore, the tracking area TA5 contains the radio base stations S13 to S14.

[0023] 5 , when communication terminal 20 moves from communication area A9 of radio base station S9 belonging to tracking area list L1 to communication area A10 of radio base station S10 belonging to tracking area list L2, communication terminal 20 transmits a location registration signal RS to MME 30. The location registration signal RS is transmitted to MME 30 via radio base station S. Therefore, an increase in the number of location registration signals RS transmitted is one factor that increases the processing load of radio base station S.

[0024] One possible measure for transmitting the location registration signal RS is to increase the number of wireless base stations S belonging to one tracking area list L. On the other hand, since the third paging signal is transmitted to all wireless base stations S belonging to one tracking area list L, it is predicted that the greater the number of wireless base stations S belonging to one tracking area list L, the greater the number of transmitted paging signals. In other words, there is a trade-off between the number of transmitted location registration signals RS and the number of transmitted paging signals.

[0025] A-2. Communication Management Device Figure 6 is a block diagram showing the configuration of the communication management device 10. The communication 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. More specifically, the communication management device 10 is, for example, a quantum computer, or a computer that is connected to a quantum computer and can cause the quantum computer to execute specific processing.

[0026] The communication 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 interconnects these devices.

[0027] The display device 101 is a display device that displays images (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, a mouse, a microphone, a switch, a button, or a sensor). The display device 101 and the input device 102 may be integrated into one device (for example, a touch panel). The communication device 103 has an interface that can be connected to a network, and communicates with other devices connected to the network using wireless or wired communication.

[0028] The storage device 104 is a recording medium readable by the processing device 105. The storage device 104 includes, for example, a non-volatile memory and a volatile memory. The non-volatile memory is, for example, a ROM (Read Only Memory), an EPROM (Erasable Programmable Read Only Memory), and an EEPROM (Electrically Erasable Programmable Read Only Memory). The volatile memory is, for example, a RAM (Random Access Memory). The storage device 104 stores a program PG1. The program PG1 is a program for operating the communication management device 10.

[0029] The processing device 105 includes one or more central processing units (CPUs). The one or more CPUs are examples of one or more processors. Each of the processors and CPUs is an example of a computer. The processing device 105 reads a program PG1 from the storage device 104. By executing the program PG1, the processing device 105 functions as a management unit 111, a first determination unit 112, a second determination unit 113, a first correction unit 114, and a display control unit 115.

[0030] The management unit 111, the first determination unit 112, the second determination unit 113, the first correction unit 114, and the display control unit 115 may be configured by circuits 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).

[0031] The management unit 111 manages a plurality of tracking areas TA including a communication area A of at least one radio base station S among the plurality of radio base stations S, and a plurality of tracking area lists L each including at least one tracking area TA among the plurality of tracking areas TA.

[0032] Taking the wireless base station S shown in FIGS. 2 to 5 as an example, the communication system 1 has at least two tracking area lists L1 and L2. Tracking area list L1 includes tracking areas TA1 to TA3. Tracking area TA1 includes communication areas A1 to A3 of wireless base stations S1 to S3. Tracking area TA2 includes communication areas A4 to A6 of wireless base stations S4 to S6. Tracking area TA3 includes communication areas A7 to A9 of wireless base stations S7 to S9. Furthermore, tracking area list L2 includes tracking areas TA4 to TA5. Tracking area TA4 includes communication areas A10 to A12 of wireless base stations S10 to S12. Tracking area TA5 includes communication areas A13 to A14 of wireless base stations S13 to S14.

[0033] The management unit 111 manages these tracking area lists L1 to L2 and tracking areas TA1 to T5. "Manage" means notifying each wireless base station S of the tracking area TA and tracking area list L determined by, for example, a first determination unit 112, a second determination unit 113, and a first correction unit 114, which will be described later.

[0034] The first determination unit 112 determines to which of the multiple tracking area lists L each of the multiple wireless base stations S belongs. In the present embodiment, the first determination unit 112 determines the tracking area list L to which each of the multiple wireless base stations S belongs by obtaining a first solution that satisfies at least one of minimizing the number of transmissions of paging signals in each of the multiple tracking area lists L and minimizing the number of transmissions of location registration signals RS that are transmitted when the communication terminal 20 moves between tracking areas TA that belong to different tracking area lists L. In the present embodiment, the first determination unit 112 determines the tracking area list L to which each of the multiple wireless base stations S belongs by obtaining, as the first solution, a solution that satisfies minimizing the number of transmissions of paging signals and minimizing the number of transmissions of location registration signals in each of the multiple tracking area lists L. Furthermore, the first determination unit 112 may determine the tracking area list L to which each of the multiple wireless base stations S belongs by obtaining, as the first solution, a solution that further satisfies equalizing the number of initial transmissions of paging signals in each of the multiple tracking area lists L.

[0035] Hereinafter, "minimizing the number of paging signal transmissions in each of the multiple tracking area lists L" may be expressed as "minimizing all paging signals." "Minimizing the number of location registration signal RS transmissions" may be expressed as "minimizing location registration signal RS." "Uniformizing the number of initial paging signal transmissions in each of the multiple tracking area lists L" may be expressed as "uniformizing first paging signals."

[0036] The second determination unit 113 determines to which of at least one tracking area TA included in one tracking area list L a wireless base station belonging to one of the multiple tracking area lists L belongs. The second determination unit 113 determines the tracking area TA to which the wireless base station S belonging to the one tracking area list L belongs by finding a second solution that minimizes the number of paging signal transmissions in the one tracking area list L.

[0037] The first determination unit 112 and the second determination unit 113 use quantum annealing to find the first solution and the second solution. Quantum annealing is known to quickly find good solutions to combinatorial optimization problems. Quantum annealing is performed in the following steps: [1] converting the objective function into QUBO (Quadratic Unconstrained Binary Optimization) format; [2] mapping to a circuit; and [3] performing quantum annealing. If the communication management device 10 is a quantum computer, the first determination unit 112 and the second determination unit 113 may perform the above steps [1] to [3]. Furthermore, if the communication management device 10 is a computer connected to a quantum computer, the first determination unit 112 and the second determination unit 113 may request the quantum computer to perform step [3] to obtain the first solution and the second solution.

[0038] In the mapping to the circuit in step [2], if there is a problem in which multiple variables are all interrelated, it is necessary to generate a topology in which the quantum bit into which each variable is embedded is connected to all other quantum bits. However, due to the current limitations of machine configuration, one variable is configured with multiple quantum bits to realize the topology. In the optimization problem of wireless base stations S handled in this embodiment, for example, the number of wireless base stations S is 300, the number of tracking areas TA is 10, the number of tracking area lists L is 3, etc., and the problem scale is large. Therefore, there is a shortage of quantum bits, and mapping cannot be done at once.

[0039] Therefore, in this embodiment, the processing is divided into two stages: the first determination unit 112 determines whether each wireless base station S belongs to the tracking area list L, and the first determination unit 112 determines whether each wireless base station S belongs to a tracking area TA. This makes it possible to divide the problem into a scale that can be solved by a quantum computer.

[0040] The following describes in detail the processing by the first determination unit 112 and the second determination unit 113. The processing by the first determination unit 112 may be referred to as "optimization of the tracking area list L" or simply as "optimization." The processing by the second determination unit 113 may be referred to as "optimization of the tracking area TA" or simply as "optimization."

[0041] The following explanation is based on the following assumptions: [1] Generally, the communication area A of each wireless base station S is made up of multiple sectors, but sectors are not taken into consideration in this optimization (sectors within the same wireless base station S are assumed to belong to the same tracking area TA). [2] Only the first re-transmission of a paging signal (third paging) is taken into consideration, and the third re-transmission (fourth paging) and beyond are not taken into consideration. [3] A paging method for data communication is used. [4] Movement of communication terminal 20 is counted in units of communication area A of wireless base station S.

[0042] Of the wireless base stations S in the communication system 1, the number of wireless base stations S to be the subject of this optimization is assumed to be e (e is an integer greater than or equal to 1). One or more tracking area lists L to be the subject of optimization are assumed to be A = {a, b, ...}. a, b, etc. indicate individual tracking area lists L. The tracking area list L indicated by a is referred to as the "ath tracking area list L." The tracking area list L indicated by b is referred to as the "bth tracking area list L." The number of tracking area lists L to be the subject of optimization is indicated as |A|. The number of tracking areas in each tracking area list L is indicated as |a|, |b|, .... The number of tracking areas TA in the tracking area list L to be the subject of optimization is indicated as fsum (= |a| + |b| + ...).

[0043] Next, the data for the simulation will be described. In this embodiment, a mobility model MP of the communication terminal 20 is used for simulating a paging signal. The mobility model MP is generated using statistical values ​​indicating the hourly mobility status of the communication terminal 20. The mobility model MP is a matrix with e rows and e columns, as shown in the following formula (1). Therefore, the mobility model MP may also be referred to as a mobility matrix. The elements (components) of the mobility model MP are denoted as mpk,i, where k and i are integers from 1 to e. mpk,i is the total number of communication terminals 20 that were located in the communication area A of the kth wireless base station S when the Nth incoming call ended, and that moved to the ith wireless base station S when the N+1th incoming call occurred.

[0044]

[0045] Furthermore, in this embodiment, a mobility model ML of the communication terminal 20 is used for simulating the location registration signal RS. The mobility model ML is generated using statistical values ​​indicating the hourly mobility status of the communication terminal 20. The mobility model ML is a matrix with e rows and e columns, as shown in the following formula (2). Therefore, the mobility model ML may also be referred to as a mobility matrix. The elements (components) of the mobility model ML are denoted as mLk,i, where k and i are integers from 1 to e. mLk,i is the total number of communication terminals 20 that have moved from the communication area A of the kth wireless base station S to the i-th wireless base station S.

[0046]

[0047] The membership of each of the e wireless base stations S to a tracking area list L and a tracking area TA is represented by matrix X shown in formula (3) below. Matrix X has e rows and fsum columns. To simplify the explanation, in formula (3) below, it is assumed that the optimization targets are two tracking area lists L, i.e., the a-th tracking area list L and the b-th tracking area list L. The elements (components) of matrix X are denoted as xai,j, for example. xai,j indicates a flag = {1, 0} indicating whether the i-th wireless base station S belongs to the j-th tracking area TA of the a-th tracking area list L. Since each wireless base station S belongs to only one tracking area list L and tracking area TA, the sum of the horizontal directions (rows) of matrix X is restricted to 1, as shown in formula (4) below.

[0048]

[0049] [Processing of first determination unit 112] [Minimization of all paging signals] Matrix X' shown in the following formula (5) is a matrix of e rows and |A| columns indicating to which tracking area list L each wireless base station S belongs. As described above, in this embodiment, the targets of optimization are the a-th tracking area list L and the b-th tracking area list L, and therefore formula (5) below shows the case where |A| = 2. The elements of matrix X' are denoted, for example, as x'ai. x'ai indicates a flag = {1, 0} indicating whether the i-th wireless base station S belongs to the a-th tracking area list L. As shown in the following formula (6), x'ai is the wireless base station S that belongs to the tracking area TA in the a-th tracking area list L.

[0050]

[0051] The total number Da of first paging signals received at a wireless base station S belonging to the a-th tracking area list L is given by the following formula (8). A parameter (pk) related to Da is given by the following formula (7). pk indicates the number of times that the position of communication terminal 20 was within communication area A of the k-th wireless base station S when the previous call was ended. In other words, pk is the number of times that first paging signals targeted at the k-th wireless base station S were generated.

[0052]

[0053] The total number D'a of second paging signals received at a radio base station S belonging to the a-th tracking area list L is given by the following equation (15). Parameters related to D'a are given by the following equations (9) to (14). R2 shown in equation (9) is a matrix with e rows and e columns indicating whether or not the radio base stations S are different radio base stations S. r2k,i shown in equation (10) is a flag indicating whether or not the k-th radio base station S and the i-th radio base station S are different radio base stations S. More specifically, r2k,i takes 1 when the k-th radio base station S and the i-th radio base station S are different radio base stations S, and takes 0 when the k-th radio base station S and the i-th radio base station S are the same radio base station S.

[0054] P'k shown in equation (11) indicates the number of times that the position of communication terminal 20 at the time of the previous call termination was within the communication area of ​​the k-th radio base station S, and the position of communication terminal 20 at the time of the current call termination was not within the communication area of ​​the k-th radio base station S. In other words, P'k is the number of occurrences of a second paging signal targeted at the k-th radio base station S.

[0055] Aaj shown in the following equation (12) is the number of wireless base stations S belonging to the jth tracking area TA in the ath tracking area list L. Baj shown in the following equation (13) is the number of second paging signals received per wireless base station S belonging to the jth tracking area TA in the ath tracking area list L. Caj shown in the following equation (14) is the total number of second paging signals received by wireless base stations S belonging to the ath tracking area list L.

[0056]

[0057]

[0058] The total number Ha of third paging signals received at a wireless base station S belonging to the a-th tracking area list L is given by the following equation (20). Parameters related to Ha are given by the following equations (16) to (19). Ra shown in equation (16) is a matrix of e rows and e columns indicating whether or not the wireless base stations S belonging to the a-th tracking area list L belong to different tracking areas TA. rak,i shown in equation (17) is a flag indicating whether or not the k-th wireless base station S and the i-th wireless base station S in the a-th tracking area list L belong to different tracking areas TA. More specifically, rak,i takes the value 1 if the k-th wireless base station S and the i-th wireless base station S belong to different tracking areas TA, and takes the value 0 if the k-th wireless base station S and the i-th wireless base station S belong to the same tracking area TA.

[0059] Ga shown in equation (18) is the total number of times the third paging signal is generated in the a-th tracking area list L. Ea shown in equation (19) is the number of wireless base stations S in the a-th tracking area list L.

[0060]

[0061]

[0062] From the above, the total number Ya of paging signals received at a wireless base station S belonging to the a-th tracking area list L is given by the following formula (21). Then, the total number Y of paging signals received at all wireless base stations S belonging to the tracking area list L to be optimized is given by the following formula (22). α in formula (22) is a weighting coefficient for the number of paging signals in each tracking area list L, and is specified during optimization calculations. The solution that minimizes Y is the solution that satisfies the "minimization of all paging signals."

[0063]

[0064] [Minimizing Location Registration Signal RS] The total number of times GL that the location registration signal RS is generated is given by equation (25) below. Parameters related to GL are given by equations (23) to (24) below. RL shown in equation (23) is a matrix with e rows and e columns indicating whether or not the respective radio base stations S belong to different tracking area lists L. rLk,i shown in equation (24) below is a flag indicating whether or not the k-th radio base station S and the i-th radio base station S belong to different tracking area lists L. More specifically, rLk,i takes the value 1 if the k-th radio base station S and the i-th radio base station S belong to different tracking area lists L, and takes the value 0 if the k-th radio base station S and the i-th radio base station S belong to the same tracking area list L. A solution that minimizes GL is a solution that satisfies the "minimization of location registration signal RS".

[0065]

[0066] [Uniformation of first paging signals] The total number Da of first paging signals received at a wireless base station S belonging to the a-th tracking area list L is shown by the above formula (8). Similarly, the total number Db of first paging signals received at a wireless base station S belonging to the b-th tracking area list L is taken as the number Db. The solution that minimizes (Da - Db)2 is the solution that satisfies the "uniformization of first paging signals."

[0067] From the above, the first determination unit 112 finds a solution that minimizes the equation f1 shown in the following equation (26) as the first solution. In equation (26), Y is a term related to minimizing all paging signals, GL is a term related to minimizing the location registration signal RS, and (Da-Db)2 is a term related to equalizing the first paging signal. β is a weighting coefficient for the location registration signal RS term. γ is a weighting coefficient for the first paging signal term.

[0068]

[0069] [Processing of second determination unit 113] The second determination unit 113 determines to which tracking area TA each wireless base station S belongs. As described above, the second determination unit 113 determines the tracking area TA to which each wireless base station S belonging to one tracking area list L belongs, by finding the second solution that minimizes the number of transmissions of all paging signals in the one tracking area list L.

[0070] [Minimizing All Paging Signals] The following description will be given taking the a-th tracking area list L as an example. The matrix X" shown in the following equation (27) is a matrix with e rows and |a| columns indicating to which tracking area TA each wireless base station S belongs. In this embodiment, for convenience of explanation, it is assumed that the a-th tracking area list L includes two tracking areas TA, c and d (hereinafter referred to as the c-th tracking area TA and the d-th tracking area TA). Therefore, the following equation (27) shows the case where |a| = 2. The elements of the matrix X" are denoted, for example, as x"ci. x"ci indicates a flag = {1, 0} indicating whether the i-th wireless base station S belongs to the c-th tracking area TA.

[0071]

[0072] The total number of times Dc that first paging signals are received at a wireless base station S belonging to the c-th tracking area TA is expressed by the following equation (29). A parameter (pk) related to Dc is expressed by the following equation (28). pk indicates the number of times that the position of communication terminal 20 was within the communication area of ​​the k-th wireless base station S when the previous call was ended. In other words, pk is the number of times that first paging signals targeted at the k-th wireless base station S are generated.

[0073]

[0074] The total number D'c of second paging signals received at a radio base station S belonging to the c-th tracking area TA is given by the following equation (36). In equation (36), |c| is the number of radio base stations belonging to the c-th tracking area TA. Parameters related to D'c are given by the following equations (30) to (35). R2 shown in equation (30) below is a matrix of e rows and e columns indicating whether or not the radio base stations S are different radio base stations S. r2k,i shown in equation (31) below is a flag indicating whether or not the k-th radio base station S and the i-th radio base station S are different radio base stations S. More specifically, r2k,i takes 1 when the k-th radio base station S and the i-th radio base station S are different radio base stations S, and takes 0 when the k-th radio base station S and the i-th radio base station S are the same radio base station S.

[0075] P'k shown in the following equation (32) indicates the number of times that the position of communication terminal 20 at the time of the previous call termination was within the communication area of ​​the k-th wireless base station S, and the position of communication terminal 20 at the time of the current call termination was not within the communication area of ​​the k-th wireless base station S. In other words, P'k is the number of occurrences of a second paging signal targeted at the k-th wireless base station S.

[0076] Acj shown in the following equation (33) is the number of wireless base stations S belonging to the c-th tracking area TA. Bcj shown in the following equation (34) is the number of second paging signals received by each wireless base station S belonging to the c-th tracking area TA. Ccj shown in the following equation (35) is the total number of second paging signals received by the wireless base stations S belonging to the c-th tracking area TA.

[0077]

[0078]

[0079] The total number Hc of receptions of the third paging signal at a radio base station S belonging to the c-th tracking area TA can be expressed as in the following formula (39). The total number of receptions of the third paging signal is the same for radio base stations S belonging to the same tracking area list L. However, if the tracking area list L includes a radio base station S with a high reception failure rate, which will be described later, and if the number of radio base stations S in the tracking area list L is relatively large (if the size of the tracking area list L is large), the number of receptions of the third paging signal will be relatively large compared to radio base stations S in other tracking area lists L.

[0080] The parameters related to Hc are shown in the following equations (37) to (38). M'P shown in the following equation (37) is a mobility model of the communication terminal 20. The mobility model M'P is generated using statistical values ​​indicating the movement status of the communication terminal 20 within the tracking area TA. The elements (components) of the mobility model M'P are denoted as m'pk,i. k and i are integers from 1 to e. m'pk,i is the total number of communication terminals 20 that were located in the communication area A of the k-th wireless base station S when the Nth incoming call ended, and that moved to the i-th wireless base station S when the N+1th incoming call arrived. ea shown in the following equation (38) is the number (constant) of wireless base stations S in the c-th tracking area TA.

[0081]

[0082] From the above, the total number Yc of paging signals received at a wireless base station S belonging to the c-th tracking area TA is given by the following equation (40). Then, the total number Yt of paging signals received at all wireless base stations S belonging to the a-th tracking area list L is given by the following equation (41). δ in equation (41) is a weighting coefficient for the number of paging signals in each tracking area TA, and is specified during optimization calculations. The solution that minimizes Yt is the second solution that satisfies the "minimization of all paging signals."

[0083]

[0084] The first correction unit 114 corrects the tracking area TA to which the radio base station S belonging to one tracking area list L determined by the second determination unit 113 belongs, based on the position of the radio base station S belonging to the one tracking area list L. If the solution obtained by the above calculation is a local solution, an optimization result that is counterintuitive may occur. Specifically, for example, two radio base stations S located close to each other may belong to different tracking areas TA, or among multiple radio base stations S belonging to the same tracking area TA, there may be a radio base station S located far away from the other radio base stations S. The first correction unit 114 corrects the optimization result by using the position information of each radio base station S. This can further improve the accuracy of the optimization result, and further reduction in paging signals and the like can be expected. Note that "correction" may be rephrased as "re-optimization."

[0085] The first correction unit 114 first selects a wireless base station S to be corrected. Then, the first correction unit 114 sets the belonging of the tracking area TA of the wireless base station S selected as the correction target as a variable, and the belonging of the tracking areas TA of the other wireless base stations S as constants, and corrects the tracking area TA to which the wireless base station S belongs by performing the calculations of the above formulas (27) to (41).

[0086] A method for selecting a wireless base station S to be corrected will be described below. The first correction unit 114 acquires latitude and longitude information of the wireless base station S to be optimized. The latitude and longitude information of the wireless base station S is an example of information indicating the position of the wireless base station S. The first correction unit 114 groups the latitude and longitude information of the wireless base stations S that belong to each tracking area TA, and obtains the center of gravity of each tracking area TA. The center of gravity of the tracking area TA may be, for example, a point at which the sum of the distances from each wireless base station S that belong to the tracking area TA is the smallest. The first correction unit 114 also calculates the distances between the center of gravity of the tracking area TA and all the wireless base stations S that belong to the tracking area TA. The first correction unit 114 selects a wireless base station S that satisfies the following [Condition 1] or [Condition 2] as the wireless base station S to be corrected.

[0087] [Condition 1] If the distance between two radio base stations S is less than d [m] and the two radio base stations S belong to different tracking areas TA, these two radio base stations S are subject to correction. In other words, the first correction unit 114 selects a first radio base station S and a second radio base station S from the radio base stations S belonging to one tracking area list L, and corrects the tracking areas to which the first radio base station S and the second radio base station S belong if the distance between the positions of the first radio base station S and the second radio base station S is less than a predetermined distance and the first radio base station S and the second radio base station S belong to different tracking areas TA.

[0088] More specifically, the first correction unit 114 calculates the distance between any two radio base stations S among the radio base stations S to be optimized using spherical trigonometry. Radio base stations S whose calculated distance is equal to or less than d [m] and which belong to different tracking areas TA after optimization are extracted without overlapping and are set as targets for correction. This allows re-optimization to be performed on radio base stations S that are assigned to different tracking areas TA despite being located in geographically close locations.

[0089] [Condition 2] The wireless base station S that ranks highest when sorted by distance from the center of gravity of the tracking area TA is the target of correction. In other words, the first correction unit 114 identifies a predetermined number of wireless base stations S that belong to one tracking area TA in order of furthest from the center of gravity of that tracking area TA, and corrects the tracking area to which the predetermined number of wireless base stations S belong.

[0090] More specifically, the first correction unit 114 calculates the distance between each wireless base station S and the center of gravity of the tracking area TA to which the wireless base station S belongs by spherical trigonometry. The first correction unit 114 targets a predetermined number of wireless base stations that are farthest from the center of gravity as targets for correction. This allows re-optimization to be performed on wireless base stations S that are farthest from the center of gravity of the tracking area TA to which they belong.

[0091] The number of radio base stations S to be corrected may be determined in advance. For example, let the number of radio base stations S to be corrected be N. When the problem scale (number of radio base stations S to be optimized × number of tracking areas TA assigned to the radio base stations S (hereinafter referred to as "number of assigned TAs")) is 5000 variables or less, for example, N = number of radio base stations S to be optimized × 50%. When the problem scale is more than 5000 variables, for example, N = 5000 / number of assigned TAs.

[0092] Furthermore, the radio base station S that satisfies condition 2 may be selected from among the radio base stations S that do not satisfy condition 1. In this case, first, the radio base station S that satisfies condition 1 is selected from among the e radio base stations S to be optimized. Assume that there are m radio base stations S that satisfy condition 1. Next, of the e-m radio base stations S that do not satisfy condition 1, the top N-m radio base stations that are farthest from the center of gravity are selected as the radio base stations S that satisfy condition 2.

[0093] Fig. 7 is a diagram schematically showing the relationship between the position of a wireless base station S and a tracking area TA. Figs. 8A and 8B are tables showing the tracking area TA to which a wireless base station S belongs. In Fig. 7, wireless base stations S1 to S8 are shown in a tracking area list L1 (denoted as "TA-List1" in the figure). It is assumed that the second determination unit 113 has determined that wireless base stations S1 to S3 and S7 belong to tracking area TA-B, wireless base stations S4 and S5 belong to tracking area TA-C, and wireless base stations S6 and S8 belong to tracking area TA-D. The star mark in each tracking area TA indicates the center of gravity of that tracking area TA.

[0094] In the table of Fig. 8A, if the number at the intersection of a wireless base station name and a tracking area name is "1", this indicates that the wireless base station S belongs to the tracking area TA. For example, wireless base station S1 belongs to tracking area TA-B.

[0095] The first correction unit 114 selects a wireless base station S that satisfies the above conditions 1 and 2 from among the wireless base stations S1 to S8. For example, wireless base station S5 and wireless base station S6 are close to each other (distance d [m] or less), but belong to different tracking areas TA. Therefore, wireless base stations S5 and S6 satisfy the above condition 1 and are determined to be targets for correction. Furthermore, wireless base station S7 is farther from the center of gravity of tracking area TA-B than the other wireless base stations S1 to S3 that belong to the same tracking area TA-B. Therefore, wireless base station S8 satisfies the above condition 2 and is determined to be a target for correction.

[0096] 8B, the first correction unit 114 performs the calculations of the above formulas (27) to (41) using the tracking area TA to which the wireless base stations S5 to S7 that are the subject of correction belong as a variable (denoted as x in the figure) and the tracking areas TA to which the other wireless base stations S1 to S4 and S8 belong as constants. This makes it possible to more accurately optimize the tracking area TA to which the wireless base station S belongs.

[0097] The display control unit 115 controls the display device 101 to display an image. Specifically, the display control unit 115 causes the display device 101 to display a radio base station figure, which is a figure indicating each radio base station S, at the position of that radio base station S on a map, and also causes the display device 101 to display, as figures, information on the state of the tracking area TA and information on the state of movement of the communication terminal 20 between each radio base station S. Specific display examples will be described later.

[0098] 9 is a flowchart showing the operation of the processing device 105 of the communication management device 10. The processing device 105 acquires various parameters (e.g., movement models MP, ML, etc.) required for calculations in the first determination unit 112 and the second determination unit 113 (step S100).

[0099] The processing device 105 functions as the first determination unit 112 and determines the tracking area list L to which each of the multiple radio base stations S belongs by finding a first solution that satisfies the uniformity of the initial paging signal, the minimization of the paging signal, and the minimization of the location registration signal RS (step S102).

[0100] In addition, the processing device 105 functions as a second determination unit 113 and determines the tracking area TA to which each radio base station S belongs by finding a second solution that satisfies the minimization of paging signals in one tracking area list L (step S104).

[0101] The processing device 105 functions as the first correction unit 114 and corrects the tracking area TA to which each wireless base station S belongs, based on the position of each wireless base station S (step S106). Thereafter, the processing device 105 outputs an optimization processing result indicating the tracking area TA to which each base station S belongs and the tracking area list L (step S108), and ends the processing of this flowchart. In accordance with the output of this optimization processing result, the management unit 111 manages the tracking area lists L1-L2 and the tracking areas TA1-TA5.

[0102] The display control unit 115 causes the display device 101 to display an image that allows the user to easily visually check the state of the optimization before or after the above-mentioned optimization, for example, at any time instructed by the administrator.

[0103] 10 is a diagram illustrating an example of an image displayed on the display device 101 of the communication management device 10 before the optimization process. As shown in Fig. 10, the display control unit 115 causes the display device 101 to display a wireless base station figure B, which is a figure representing each wireless base station S, at the position of the wireless base station S on the map M displayed on the display device 101.

[0104] Furthermore, the display control unit 115 causes the display device 101 to display information regarding the status of the tracking area TA in the form of a graphic on the map M. The status of the tracking area TA here refers to the status regarding the affiliation of the wireless base station S in the tracking area TA, such as which wireless base station S belongs to each tracking area. Here, the display control unit 115 displays a wireless base station graphic B, which is a graphic representing a wireless base station S, in a display mode that makes it possible to identify the tracking area TA to which the wireless base station S belongs. In FIG. 10 , the wireless base station graphic B is represented by a circle, a square, a triangle, and an X-shape, but the differences in these graphic shapes actually represent differences in color on the display. In other words, the circle, square, triangle, and X-shape are each represented by a graphic of a different color. In other words, the display control unit 115 displays each wireless base station graphic B in a color that makes it possible to identify the tracking area TA to which the wireless base station S belongs. As can be seen from FIG. 10 , before the optimization process, the positions of the wireless base station graphic B represented by different shapes (actually different colors) are dispersed without being concentrated in any particular region. This means that when the communication terminal 20 moves, the frequency or probability that it is located in the same tracking area TA before and after the movement is not high.

[0105] Here, the display control unit 115 displays the radio base station figure B in a display mode according to the number of paging signals transmitted from the radio base station S corresponding to that radio base station figure B. Here, the display control unit 115 displays the radio base station figure B in a size according to the number of paging signals transmitted from the radio base station S corresponding to that radio base station figure B. Therefore, in Fig. 10, the sizes of the radio base station figures B are actually different.

[0106] Furthermore, the display control unit 115 causes the display device 101 to display, as a graphic, information related to the state of movement of the communication terminal 20 between each radio base station S. Regarding the movement of the communication terminal 20 between each radio base station S, for example, each time the communication terminal 20 accesses a radio base station S, the MME 30 can identify from which communication area of ​​which radio base station S the communication terminal 20 has moved to. The display control unit 115 displays a movement state graphic U which is a graphic indicating the state of movement of the communication terminal 20 between each radio base station S. In the example of Fig. 10 , the display control unit 115 displays the movement state graphic U which is a dashed line connecting each radio base station (radio base station graphic B) and has a thickness corresponding to the number of movements of the communication terminal 20 between each radio base station (radio base station graphic B). Therefore, the thickness of each movement state graphic U is different in Fig. 10 .

[0107] Furthermore, the display control unit 115 displays a movement state graphic U1 indicating the state of movement of the communication terminal 20 between wireless base stations S belonging to one tracking area list L (first tracking area list) and a movement state graphic U2 indicating the state of movement of the communication terminal 20 between wireless base stations S belonging to a different tracking area list L (second tracking area list) in a display mode that allows each to be distinguished. In Fig. 10, the movement state graphic U1 is represented by a dashed line and the movement state graphic U2 is represented by a two-dot dashed line, but in reality, the movement state graphic U1 and the movement state graphic U2 are displayed in different colors.

[0108] Next, Figure 11 is a diagram illustrating an example of an image displayed on the display device 101 of the communication management device 10 at a point after the optimization process according to this embodiment, and Figure 12 is a diagram explaining considerations regarding the image displayed on the display device 101 of the communication management device 10 at a point after the optimization process.

[0109] In Figure 11, the display control unit 115 causes the display device 101 to display a radio base station figure B at the position of each radio base station S on a map M displayed on the display device 101, and also causes the display device 101 to display information regarding the state of the tracking area TA using a figure, and further causes the display device 101 to display information regarding the state of movement of the communication terminal 20 between each radio base station S using a figure.

[0110] As can be seen by comparing Figures 10 and 11, before the optimization process, the locations of radio base station figures B represented by different shapes (actually different colors) were dispersed, whereas after the optimization process, the locations of radio base station figures B represented by the same shape (actually the same color) tend to be concentrated in certain areas. For easier understanding, in Figure 12, radio base station figures B represented by the same shape (actually the same color) are enclosed in frames f (f1 to f4). This clearly shows that the tracking areas TA to which radio base stations S belong are each biased in location. This means that even if communication terminal 20 moves, there is a high frequency or probability that it will be located in the same tracking area TA before and after the move. This shows that the tracking area to which radio base station S belongs and the tracking area list are optimized, thereby minimizing the number of paging signal transmissions.

[0111] As described above, when optimizing the tracking area TA and tracking area list L to which each wireless base station S belongs, the communication management device 10 according to the embodiment first determines the tracking area list L to which each wireless base station S belongs, and then determines the tracking area TA to which each wireless base station S belongs. By dividing the processing into two stages, a solution can be obtained even when the number of wireless base stations S is large and the problem is large in scale.

[0112] Furthermore, the communication management device 10 uses quantum annealing to determine the tracking area list L and tracking area TA to which each wireless base station S belongs. This allows the calculation time to be dramatically reduced compared to a classical computer, and allows the device 10 to solve problems that cannot be solved by a classical computer.

[0113] Furthermore, the communication management device 10 corrects the tracking area TA to which each wireless base station S belongs, based on the position of each wireless base station S. Therefore, even if a counterintuitive optimization result occurs, such as when the solution obtained by the calculation is a local solution, re-optimization can be performed, and the tracking area TA to which the wireless base station S belongs can be optimized with greater accuracy.

[0114] Then, the communication management device 10 according to the embodiment controls the display device 101 to display an image. Specifically, the display control unit 115 causes the display device 101 to display a radio base station figure, which is a figure indicating each radio base station S, at the position of the radio base station S on the map, and also causes the display device 101 to display, as figures, information on the state of the tracking area TA and information on the state of movement of the communication terminal 20 between each radio base station S. This makes it possible to visually confirm how the tracking area to which the radio base station S belongs and the tracking area list have been optimized.

[0115] B: Modifications B1: First Modification In the above-described embodiment, the assignment of a radio base station S to the tracking area list L is determined so as to satisfy the requirements of minimizing all paging signals, minimizing location registration signals RS, and uniforming the first paging signal. In addition to this, the assignment of a radio base station S to the tracking area list L may be determined taking into account the failure rate of incoming calls.

[0116] 13 is a block diagram showing the configuration of a communication management device 10A according to the first modification. In addition to the configuration of the communication management device 10 described above, the communication management device 10A according to the first modification includes a second correction unit 116. The second correction unit 116 corrects the tracking area list L to which each of the multiple wireless base stations S determined by the first determination unit 112 belongs, based on the failure rate of paging signal reception at each of the multiple wireless base stations S.

[0117] As described above, the paging signal is transmitted multiple times while expanding the transmission area. The third paging signal is transmitted to all wireless base stations S in the tracking area list L, but if the destination communication terminal 20 is unable to receive radio waves, a fourth paging signal (hereinafter referred to as the "fourth paging signal") is transmitted.

[0118] The fourth paging signal is transmitted from all wireless base stations S in the tracking area list L. Therefore, after the fourth paging signal is transmitted, the total number of paging signal transmissions in one tracking area list L is approximately twice the total number of paging signal transmissions up to the third paging signal. For example, assume that the number of wireless base stations S in the tracking area TA to which a certain wireless base station S belongs is 30, and the number of wireless base stations S in the tracking area list L is 300. In this case, the total number of transmissions up to the third paging signal is 331 (the first paging signal 1 + the second paging signal 30 + the third paging signal 300), whereas the total number of transmissions after the transmission of the fourth paging signal becomes 631 (the above 331 + the fourth paging signal 300). A total of 631 paging signals are transmitted to check the coverage status of one communication terminal 20. As such, the majority of paging signals transmitted from wireless base stations S are due to failed incoming call requests. Therefore, it is desirable to optimize the tracking area list L taking into account failed incoming call requests.

[0119] In this embodiment, a "successful call" is defined as a call destination terminal responding to any of the first to third paging signals (when paging is completed), and a "failed call" is defined as a call destination terminal transmitting a fourth paging signal (when paging is incomplete). The second correction unit 116 simulates paging signals generated in each tracking area list L using the belonging states of the multiple wireless base stations S to the tracking area list L determined by the first determination unit 112 and the mobility model MP. The second correction unit 116 then calculates the failure rate of each wireless base station S using the following equation (42). In the following equation (42), the "success-derived transmission count" is the number of paging signals transmitted from one wireless base station S that are derived from successful call requests. The "failure-derived transmission count" is the total number of paging signals transmitted from one wireless base station S minus the "success-derived transmission count."

[0120] Failure rate = (number of failed calls) / (number of successful calls + number of failed calls) (42)

[0121] Reasons why the destination communication terminal 20 cannot receive radio waves include, for example, the power of the communication terminal 20 being turned off, the communication terminal 20 being in an out-of-service area, or the communication terminal 20 being located around a building that makes it difficult for radio waves to connect. Of these reasons, the out-of-service area and the building that makes it difficult for radio waves to connect are fixed conditions, so the failure rate varies for each wireless base station S. Therefore, the second correction unit 116 calculates the failure rate for each wireless base station S and adjusts the assignment to the tracking area list L so that wireless base stations S with high failure rates are not concentrated in some tracking area lists L.

[0122] As an example, the second correction unit 116 may divide or reorganize N tracking area lists L (N is an integer equal to or greater than 1) including a tracking area list L to which a wireless base station S with a high failure rate belongs, into N+1 or more tracking area lists L. This reduces the total number of paging signals transmitted in one tracking area list L. In this case, it is preferable to prevent extreme variations in the number of belonging wireless base stations S among the N+1 or more tracking area lists L (or all tracking area lists L managed by the telecommunications carrier) after division or reorganization. In other words, it is preferable to perform division or reorganization so that the number of belonging wireless base stations S in one tracking area list L is within a predetermined range.

[0123] As another example, the second correction unit 116 may assign wireless base stations S with high failure rates to different tracking area lists L so that the average value of the failure rates of the wireless base stations S belonging to each tracking area list L is within a certain range.

[0124] According to the first modification, the failure rate of incoming calls is taken into consideration when determining whether a wireless base station S should belong to the tracking area list L. This distributes the processing load resulting from failed incoming call requests, which account for a large portion of paging signals, and improves the processing efficiency of the communication system 1.

[0125] In addition, the second correction unit 116 may correct the tracking area TA to which each of the multiple radio base stations S determined by the second determination unit 113 belongs, based on the failure rate of paging signal reception at each of the multiple radio base stations S.

[0126] B2: Second Modification Based on the failure rate described in the first modification, for example, the tracking area TA to which each wireless base station S belongs in the currently operated tracking area list L may be optimized. That is, the communication management device 10 may include a management unit 111 that manages multiple tracking areas TA including the communication area of ​​at least one wireless base station among the multiple wireless base stations S and multiple tracking area lists L, each including at least one tracking area TA among the multiple tracking areas TA, and a third determination unit (not shown) that determines to which of at least one tracking area TA included in the tracking area list L a wireless base station S belonging to one of the multiple tracking area lists L belongs. In this case, the third determination unit determines the tracking area TA to which a wireless base station S belonging to one tracking area list L belongs, based on a mobility model MP that indicates the movement status of the communication terminal 20 within one tracking area list L and the failure rate of paging signal reception at each of the multiple wireless base stations S.

[0127] Specifically, the third determination unit simulates paging signals generated in each tracking area list L, for example, by using the belonging state of each currently operated wireless base station S to the tracking area list L and the mobility model MP. The third determination unit calculates the failure rate of each wireless base station S by using the above formula (42). The third determination unit determines the belonging of each wireless base station S to a tracking area TA so that there is no large variation in the failure rates of the wireless base stations S belonging to each tracking area TA.

[0128] According to the second modification, the tracking area TA of the wireless base station S is determined taking into consideration the failure rate of incoming calls. This distributes the processing load resulting from failed incoming call requests, which account for a large portion of paging signals, and improves the processing efficiency of the communication system 1.

[0129] B3: Third Modification In the above-described embodiment, the tracking area list L and the tracking area TA to which each wireless base station S belongs are optimized regardless of the current state of belonging of each wireless base station S to the tracking area list L and the tracking area TA (hereinafter referred to as the "current belonging state"). On the other hand, optimization may be performed based on the current belonging state.

[0130] Specifically, the first determination unit 112 calculates the number of paging signal transmissions and the number of location registration signal transmissions based on the current belonging state and the mobility models MP and ML. Then, the first determination unit 112 calculates, as a first solution, a number that minimizes one of the number of paging signal transmissions and the number of location registration signal transmissions, while keeping the other of the number of paging signal transmissions and the number of location registration signal transmissions at the same level as the current belonging state, as a constraint.

[0131] First, consider the case where a constraint is set to minimize the number of location registration signal transmissions and to keep the number of paging signal transmissions at the same level as the current belonging state. When only the number of location registration signal transmissions is minimized, the coefficients α and γ in the above equation (26) are set to 0. Regarding the constraint, for example, a solution is searched for in which the number of paging signal transmissions after optimization is less than the number of paging signal transmissions in the current belonging state. The number of paging signal transmissions in the current belonging state is obtained by substituting the current belonging state and the mobility model MP into the above equation (21). The number of paging signal transmissions after optimization is obtained by substituting the belonging state (matrix X) after optimization and the mobility model MP into the above equation (21).

[0132] Next, consider the case where a constraint is set to minimize the number of paging signal transmissions and keep the number of location registration signal transmissions at the same level as the current belonging state. When only the number of paging signal transmissions is minimized, the coefficients β and γ in the above equation (26) are set to 0. Regarding the constraint, for example, a solution is searched for in which the number of location registration signal transmissions after optimization is less than the number of location registration signal transmissions in the current belonging state. The number of location registration signal transmissions in the current belonging state is obtained by substituting the current belonging state and the mobility model ML into the above equation (25). The number of location registration signal transmissions after optimization is obtained by substituting the belonging state (matrix X) after optimization and the mobility model ML into the above equation (25).

[0133] That is, in the third modification, the first determination unit 112 determines a provisional belonging state of each of the multiple wireless base stations S to a tracking area TA and a tracking area list L, and calculates the number of paging signal transmissions and the number of location registration signal transmissions in each of the multiple tracking area lists L in the provisional belonging state, based on mobility models MP and ML that indicate the movement status of the communication terminal 20. The first determination unit 112 determines the tracking area list L to which each of the multiple wireless base stations S belongs by obtaining, as a first solution, a solution that minimizes one of the number of paging signal transmissions or the number of location registration signal transmissions in each of the multiple tracking area lists L and makes the other of the number of paging signal transmissions or the number of location registration signals equivalent to the number of transmissions in the provisional belonging state. The provisional belonging state is, for example, the current belonging state.

[0134] According to the third modification, it is possible to optimize the affiliation of each wireless base station S to the tracking area TA and the tracking area list L based on the current affiliation state. This reduces the processing load on the communication management device 10 and improves the processing efficiency in the communication system 1 without making large-scale changes to affiliation.

[0135] B4: Fourth Modification The display control unit 115 may be configured to display text information relating to details of the movement state indicated by the selected movement state figure U when the user selects the movement state figure U, and to display text information relating to details of the radio base station S indicated by the selected radio base station figure B when the user selects the radio base station figure B. The details of the movement state here may be, for example, the number of movements of the communication terminal 20. Furthermore, the details of the radio base station S may be, for example, the tracking area TA and tracking area list L to which the radio base station S belongs, the number of paging messages transmitted from the radio base station S, etc.

[0136] C: Others (1) In the above-described embodiment, ROM, RAM, etc. are given as examples of storage device 104, but storage device 104 may also be a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray (registered trademark) disk), a smart card, a flash memory device (e.g., a card, a stick, a key drive), a CD-ROM (Compact Disc-ROM), a register, a removable disk, a hard disk, a floppy (registered trademark) disk, a magnetic strip, a database, a server, or other suitable storage medium.

[0137] (2) In the above-described embodiments, the described information, signals, etc. may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0138] (3) In the above-described embodiment, input and output information may be stored in a specific location (for example, a memory) or may be managed using a management table. Input and output information may be overwritten, updated, or added to. Output information may be deleted. Input information may be transmitted to another device.

[0139] (4) In the above-described embodiment, the determination may be made based on a value represented by one bit (0 or 1), a Boolean value (true or false), or a comparison of numerical values ​​(e.g., a comparison with a predetermined value).

[0140] (5) The order of the process procedures, sequences, flowcharts, etc. illustrated in the above-described embodiments may be rearranged unless it is consistent. For example, the methods described in this disclosure present elements of various steps using an example order, and are not limited to the particular order presented.

[0141] (6) Each function illustrated in FIG. 6 is realized by any combination of hardware and / or software. Furthermore, the method for realizing each functional block is not particularly limited. That is, each functional block may be realized using a single device that is physically or logically coupled, or may be realized using two or more physically or logically separated devices that are directly or indirectly connected (e.g., wired, wireless, etc.) and these multiple devices. A functional block may be realized by combining software with the single device or multiple devices.

[0142] (7) The programs exemplified in the above-described embodiments should be broadly construed to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., regardless of whether they are called software, firmware, middleware, microcode, hardware description language, or by other names.

[0143] Software, instructions, information, etc. may also be transmitted or received over a transmission medium. For example, if software is transmitted from a website, server, or other remote source using wired technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave), then these wired and / or wireless technologies are included within the definition of transmission media.

[0144] (8) In each of the foregoing embodiments, the terms "system" and "network" are used interchangeably.

[0145] (9) The information, parameters, etc. described in this disclosure may be expressed using absolute values, relative values ​​from a predetermined value, or corresponding other information.

[0146] (10) In the above-described embodiments, the portable device may be a mobile station (MS). Those skilled in the art may also refer to a mobile station 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 some other appropriate terminology. In this disclosure, the terms "mobile station," "user terminal," "user equipment (UE)," "terminal," etc. may be used interchangeably.

[0147] (11) In the above-described embodiments, the terms "connected," "coupled," or any variation thereof refers to 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" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access." As used in this disclosure, two elements may be considered to be "connected" or "coupled" to each other using at least one of one or more wires, cables, and printed electrical connections, as well as electromagnetic energy having wavelengths in the radio frequency range, microwave range, and optical (both visible and invisible) range, as some non-limiting and non-exhaustive examples.

[0148] (12) In the above embodiments, the phrase "based on" does not mean "based only on," unless otherwise specified. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0149] (13) As used in this disclosure, the terms "determining" and "determining" may encompass a wide variety of actions. "Determining" and "determining" may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, inquiring (e.g., searching in a table, database, or other data structure), ascertaining something as "determining" or "determining," and the like. Furthermore, "judgment" and "decision" may include regarding receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, and accessing (e.g., accessing data in memory) as having been "judgment" or "decision." Furthermore, "judgment" and "decision" may include regarding resolving, selecting, choosing, establishing, comparing, etc. as having been "judgment" or "decision." In other words, "judgment" and "decision" may include regarding some action as having been "judgment" or "decision." Furthermore, "judgment" may be interpreted as "assuming," "expecting," "considering," etc.

[0150] (14) In the above embodiments, when "include," "including," and variations thereof are used, these terms are intended to be inclusive, similar to the term "comprising." Furthermore, the term "or," as used in this disclosure, is not intended to be an exclusive or.

[0151] (15) In this disclosure, where articles are added by translation, such as a, an, and the in English, this disclosure may include the noun following these articles being plural.

[0152] (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 "combined" may also be interpreted in the same way as "different."

[0153] (17) The aspects / embodiments described in this disclosure may be used alone, in combination, or switched depending on the implementation. Notification of predetermined information (e.g., notification that "X is true") is not limited to being explicit, but may be implicit (e.g., not notifying the predetermined information).

[0154] 1...communication system, 10, 10A...communication management device, 20...communication terminal, 101...display device, 102...input device, 103...communication device, 104...storage device, 105...processing device, 111...management unit, 112...first determination unit, 113...second determination unit, 114...first correction unit, 115...display control unit, 116...second correction unit, A (A1 to A14)...communication area, L (L1, L2)...tracking area list, PG1...program, S (S1 to S14)...wireless base station, TA (TA1 to TA5)...tracking area, B...wireless base station figure, U...movement state figure, M...map.

Claims

1. A processing device characterized by having a display control unit that causes a display device to display a radio base station figure, which is a figure indicating each radio base station, at the position of the radio base station on a map, and also causes the display device to display, as figures, information regarding the status of a tracking area consisting of the communication areas of one or more of the radio base stations and information regarding the status of movement of communication terminals between each of the radio base stations.

2. The processing device according to claim 1, characterized in that the display control unit displays a radio base station figure, which is a figure representing the radio base station, in a display format that makes it possible to identify the tracking area to which the radio base station belongs.

3. The processing device according to claim 2, characterized in that the display control unit displays a radio base station figure, which is a figure representing the radio base station, in a color that makes it possible to identify the tracking area to which the radio base station belongs.

4. The processing device according to claim 1, wherein said display control unit displays a movement status graphic which is a graphic indicating the state of movement of a communication terminal between each of said wireless base stations.

5. The processing device according to claim 4, characterized in that the display control unit connects each of the wireless base stations and displays the movement status graphic with a thickness corresponding to the number of movements of communication terminals between each of the wireless base stations.

6. A processing device as described in claim 4, characterized in that one tracking area list is composed of a plurality of the tracking areas, and the display control unit displays a movement status graphic indicating the movement status of a communication terminal between radio base stations belonging to a first tracking area list and a movement status graphic indicating the movement status of a communication terminal between radio base stations belonging to a second tracking area list in a display manner that allows each to be distinguished.

7. The processing device according to claim 1, characterized in that the display control unit displays the radio base station figure in a display mode according to the number of paging signals transmitted from the radio base station corresponding to the radio base station figure.

8. The processing device according to claim 7, characterized in that the display control unit displays the radio base station figure in a size according to the number of paging signals transmitted from the radio base station corresponding to the radio base station figure.

9. The processing device according to claim 4, characterized in that when a movement state figure is selected, the display control unit displays text information relating to details of the movement state indicated by the selected movement state figure, and when a radio base station figure is selected, the display control unit displays text information relating to details of the radio base station indicated by the selected radio base station figure.

10. A display control method for displaying on a display device a radio base station figure, which is a figure indicating each radio base station, at the position of the radio base station on a map, and displaying on the display device information relating to the status of a tracking area consisting of the communication areas of one or more of the radio base stations, and information relating to the status of movement of communication terminals between each of the radio base stations, each in the form of a figure.

Images