JP2011119976A - Base station, wireless controller, core network device and area map creation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To create a trouble area map that indicates the locations of communication troubles. <P>SOLUTION: A location information acquisition part 1a of a base station 1 periodically acquires location information of a wireless terminal 3, and a location information storage part 1b stores the acquired location information into a storage device 1c. A communication trouble detector 1d detects a communication trouble of the wireless terminal 3, and if any communication trouble is detected, a transmitter 1e transmits area map creation information including the latest location information stored in the storage device 1c of the wireless terminal 3 where the communication trouble has been detected to an area map creation device 2. A receiver 2a of the area map creation device 2 receives the area map creation information including the location information when the communication trouble of the wireless terminal 3 occurs from the base station 1. An area map creation part 2b plots the location information included in the received area map creation information on a map, and creates a trouble area map indicating the location in which the communication trouble has occurred. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  This case relates to the creation of an area map in wireless communication.

  Some wireless communication systems create an area map so that the communication quality in a service area can be grasped. As a technique for creating an area map, for example, the following technique is known.

  The database server determines measurement area range information specifying an area in which the number of communication quality information is equal to or less than a predetermined threshold, and transmits a measurement request including the measurement area range information to the wireless terminal. The wireless terminal determines whether communication area information based on the position of the wireless terminal itself is included in the measurement area range information included in the measurement request received from the database server. When the determination is true, the wireless terminal returns the current position information and the communication quality information to the database server. As a result, the number of transmissions of the communication quality information in the wireless terminal is reduced as much as possible so that the entire network is not burdened (see, for example, Patent Document 1).

  As another example, the area diagnostic device collects call detail information of each mobile terminal via a base station. Further, the area diagnosis apparatus creates a base station information file including at least the station number and position information of the base station for a plurality of base stations. The area diagnosis apparatus acquires call quality of each mobile terminal, station numbers of a plurality of base stations in the vicinity of each mobile terminal, and signal propagation time information from the detailed call information and the base station information file. The area diagnosis apparatus obtains the position of the mobile terminal based on the station number information and position information of a plurality of base stations in the vicinity of each mobile terminal and the signal propagation time information. The area diagnosis apparatus outputs the position information of the mobile terminal thus obtained in association with the call quality information obtained from the call detail information, and plots it on a map. Parameters such as call quality are filtered as necessary and plotted on a map. This makes it possible to estimate the distribution of call quality in each area efficiently and in real time (see, for example, Patent Document 2).

JP 2008-306240 A JP 2005-94634 A

However, the conventional apparatus creates an area map indicating communication quality, and does not create an area map indicating a position where a communication failure occurs.
The present invention has been made in view of the above points, and an object thereof is to provide a base station, a radio network controller, a core network device, and an area map creation device that can create an area map indicating a communication failure occurrence position. And

  In order to solve the above problem, a base station that performs wireless communication with a wireless terminal is provided. The base station includes a position information acquisition unit that periodically acquires position information of the wireless terminal, a position information storage unit that stores the position information acquired by the position information acquisition unit in a storage device, and the wireless terminal A communication failure detection unit that detects a communication failure of the wireless terminal, and when the communication failure is detected by the communication failure detection unit, the latest location stored in the storage device of the wireless terminal where the communication failure is detected A transmission unit that transmits area map creation information including information to the area map creation device.

  Moreover, in order to solve the said subject, the area map production apparatus which produces an area map is provided. This area map creation device receives area map creation information including location information when a communication failure of a radio terminal occurs from a base station, a radio network controller that controls the base station, or a core network device that controls the radio network controller And an area map creation unit that plots the location information included in the area map creation information received by the reception unit on a map and creates a fault occurrence area map indicating a location where a communication fault has occurred. .

  According to the disclosed base station and area map creation device, it is possible to create a failure occurrence area map indicating a position where a communication failure has occurred.

It is the figure which showed the area map creation system which concerns on 1st Embodiment. It is the figure which showed the area map creation system which concerns on 2nd Embodiment. It is a figure explaining the outline of preparation of a failure occurrence area map. It is a flowchart explaining the outline of preparation of a failure occurrence area map. It is a block diagram of an area map creation device. It is a block diagram of eNodeB. It is a block diagram of a radio | wireless terminal. It is a sequence diagram of an area map creation system when no communication failure occurs. It is a sequence diagram of an area map creation system when a communication failure occurs. It is the figure which showed the failure occurrence area map. It is the 1 of the figure which showed the cell area adjustment map. It is the 2 of the figure which showed the cell area adjustment map. It is a sequence diagram of cell area adjustment. It is a block diagram of eNodeB which concerns on 3rd Embodiment. It is the figure which showed the data structural example of the memory | storage device. It is a figure explaining the position estimation of a failure occurrence.

Hereinafter, a first embodiment will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing an area map creation system according to the first embodiment. As shown in FIG. 1, the area map creation system includes a base station 1, an area map creation device 2, and a wireless terminal 3.

The base station 1 includes a location information acquisition unit 1a, a location information storage unit 1b, a storage device 1c, a communication failure detection unit 1d, and a transmission unit 1e.
The position information acquisition unit 1a periodically acquires the position information of the wireless terminal 3.

The position information storage unit 1b stores the position information acquired by the position information acquisition unit 1a in the storage device 1c.
The communication failure detection unit 1d detects a communication failure of the wireless terminal 3. For example, the communication failure detection unit 1d detects a communication disconnection with the wireless terminal 3.

  When a communication failure is detected by the communication failure detection unit 1d, the transmission unit 1e generates area map generation information including the latest location information stored in the storage device 1c of the wireless terminal 3 in which the communication failure is detected. Transmit to device 2.

The area map creation device 2 includes a reception unit 2a and an area map creation unit 2b.
The receiving unit 2a receives area map creation information including position information transmitted from the transmitting unit 1e of the base station 1.

  The area map creation unit 2b plots the position information included in the area map creation information received by the reception unit 2a on the map, and creates a failure occurrence area map indicating the location where the communication failure has occurred.

  Thus, the base station 1 periodically acquires the position information of the wireless terminal 3 and stores it in the storage device 1c. When the base station 1 detects a communication failure of the wireless terminal 3, the base station 1 transmits area map creation information including the latest position information of the wireless terminal 3 stored in the storage device 1 c to the area map creation device 2. The area map creation device 2 receives area map creation information from the base station 1 and plots position information included in the area map creation information on the map.

  Thereby, the position information transmitted to the area map creation device 2 is the position information immediately before the communication failure of the wireless terminal 3, and can be regarded as the position information of the wireless terminal 3 when the communication failure occurs. The area map creation device 2 can create a failure occurrence area map indicating a position where a communication failure has occurred.

Next, a second embodiment will be described in detail with reference to the drawings.
FIG. 2 is a diagram showing an area map creation system according to the second embodiment. As shown in FIG. 2, the area map creation system includes, for example, an area map creation device 11, which is a server, an RNC (Radio Network Controller) 12, a BTS (Base Transceiver Station) 13, an eNodeB (enhanced Node B) 14, and a wireless terminal 15. , 16.

  The RNC 12 and the BTS 13 form a 3G (the 3rd Generation) system, and the eNodeB 14 forms an LTE (Long Term Evolution) system. The area map creation system in FIG. 2 shows an example having two systems, a 3G system and an LTE system, but may have only one system. In the following description, the area map creation system will describe a case where an area map is created in the LTE system.

  FIG. 3 is a diagram for explaining the outline of creation of the failure occurrence area map. FIG. 3 shows the area map creation device 11, eNodeB 14, and wireless terminal 16 shown in FIG. 2. FIG. 3 shows an eNodeB 21 not shown in FIG.

  First, the operator of the area map creation device 11 issues a measurement instruction for creating a failure occurrence area map to the eNodeB 14. The operator instructs the measurement period for creating the failure occurrence area map to the eNodeB 14 when the failure occurrence area map is measured. For example, the operator instructs a measurement period such as 1 hour, 1 day, or 1 week.

  Upon receiving the measurement instruction from the area map creation device 11, the eNodeB 14 acquires the communication quality from all the wireless terminals 16 belonging to the subordinate. The communication quality is, for example, the transmission power of the wireless terminal 16 or a BLER (BLock Error Rate) value.

  The eNodeB 14 extracts the wireless terminal 16 that does not satisfy the predetermined communication quality. For example, the wireless terminal 16 performing wireless communication with transmission power larger than a predetermined threshold or the wireless terminal 16 having a BLER value larger than the predetermined threshold is extracted.

  When the eNodeB 14 extracts the wireless terminal 16 that does not satisfy the predetermined communication quality, the eNodeB 14 requests the extracted wireless terminal 16 to periodically transmit the position information as illustrated in FIG. That is, the eNodeB 14 requests the wireless terminal 16 having a low communication quality that is likely to cause a communication failure to transmit the position information.

  As illustrated in FIG. 3B, the wireless terminal 16 that has received the position information transmission request acquires its own position information and transmits it to the eNodeB 14. For example, the wireless terminal 16 acquires a position where the wireless terminal 16 is present by GPS (Global Positioning System) and transmits the acquired position to the eNodeB 14. Thereby, eNodeB14 can acquire the positional information on the radio | wireless terminal 16 with high possibility of causing a communication failure.

  The eNodeB 14 stores the acquired position information in a storage device such as a RAM (Random Access Memory). The eNodeB 14 stores the acquired position information in the storage device for each wireless terminal.

  The eNodeB 14 repeats the process of acquiring the communication quality, extracting the wireless terminal 16, acquiring the extracted position information of the wireless terminal 16, and storing the acquired position information. When a communication failure occurs in the wireless terminal 16 during the execution of these processes, the eNodeB 14 acquires the latest location information of the wireless terminal 16 in which the communication failure has occurred, stored in the storage device, and the area map Transmit to the creation device 11.

  For example, as illustrated in FIG. 3C, it is assumed that the wireless terminal 16 moves from the cell of the eNodeB 14 to the cell of the eNodeB 21. When the radio terminal 16 moves from the eNodeB 14 cell to the eNodeB 21 cell, the radio terminal 16 performs DHO (Diversity Hand Over) procedures with the eNodeB 14. An intermittent communication failure occurs.

  When a communication failure occurs, the eNodeB 14 acquires the latest position information of the wireless terminal 16 stored in the storage device. The latest position information stored in the storage device is position information immediately before the communication failure of the wireless terminal 16 occurs, and can be regarded as the position information of the wireless terminal 16 when the failure occurs. That is, the eNodeB 14 can acquire the position information of the wireless terminal 16 when a failure occurs and transmit it to the area map creation device 11. 3 indicates the position information of the wireless terminal 16 stored in the storage device.

  In addition, the eNodeB 14 acquires the cause of the failure that caused the communication failure and transmits it to the area map creation device 11. In the example of FIG. 3C, since the eNodeB 14 receives a communication failure due to communication interruption during the DHO procedure with the wireless terminal 16, it can be recognized that the DHO has failed, and the failure factor of the DHO failure can be identified as the area map creation device 11. Send to.

  The eNodeB 14 repeats the above process for the measurement period designated by the area map creation device 11. Therefore, in the area map creation device 11, for example, as indicated by the crosses in FIG. 3D, the location information and the cause of failure of the wireless terminal 16 are obtained.

  When the measurement period expires, the area map creation device 11 creates a failure occurrence area map based on the acquired position information. Moreover, the area map creation apparatus 11 can recognize that the cells of the eNodeB 14 and the eNodeB 21 are not continuous based on a failure factor of DHO failure, for example.

  The area map creation device 11 adjusts the cell area of the eNodeB 14 based on the created area map so that no failure occurs. For example, the area map creation device 11 controls the eNodeB 14 so that the cell of the eNodeB 14 becomes large so that the cells of the eNodeB 14 and the eNodeB 21 are continuous.

  In the above description, the failure of DHO has been described as an example of the failure factor. However, as other failure factors, squelch loss (radio synchronization loss), CN (Core Network) device and wireless terminal state mismatch, resource shortage (congestion), There is a procedure error. The eNodeB 14 can recognize these failure factors and can transmit them to the area map creation device 11 together with the location information of the wireless terminal 16.

  In FIG. 3, the operator issues a failure area map measurement instruction only to the eNodeB 14, but can also issue a failure area map measurement instruction to a plurality of eNodeBs.

FIG. 4 is a flowchart for explaining the outline of creation of the failure occurrence area map.
[Step S1] The area map creation device 11 instructs the eNodeB 14 to make a measurement for creating a failure area map. At this time, the area map creation device 11 instructs the eNodeB 14 for a measurement period for creating a failure occurrence area map.

[Step S2] Upon receiving the measurement instruction from the area map creation device 11, the eNodeB 14 acquires the communication quality of all the wireless terminals 16 belonging to the subordinate.
[Step S3] The eNodeB 14 extracts wireless terminals 16 that do not satisfy the predetermined communication quality. That is, the eNodeB 14 extracts wireless terminals 16 that are highly likely to cause a communication failure.

  [Step S4] The eNodeB 14 receives the location information from the extracted wireless terminal 16, and stores it in the storage device. The eNodeB 14 overwrites the position information for each wireless terminal and stores it in the storage device.

  [Step S5] The eNodeB 14 determines whether a communication failure has occurred in communication with the wireless terminal 16. The eNodeB 14 proceeds to step S6 if a communication failure has occurred, and proceeds to step S7 if no communication failure has occurred.

  [Step S6] The eNodeB 14 acquires a failure factor of communication failure, and transmits area map creation information including the acquired failure factor and the location information stored in the storage device to the area map creation device 11. Since the location information is overwritten and stored in the storage device, the eNodeB 14 transmits the latest location information to the area map creation device 11 when a communication failure occurs.

  [Step S7] The eNodeB 14 determines whether the measurement period instructed from the area map creation device 11 has elapsed. The eNodeB 14 proceeds to step S2 when the measurement period has not elapsed, and proceeds to step S8 when the measurement period has elapsed.

  [Step S8] The area map creation device 11 creates a failure occurrence area map based on the position information received from the eNodeB 14. The area map creation device 11 adjusts the cell area based on the created failure occurrence area map so that no failure occurs.

  FIG. 5 is a block diagram of the area map creation device. As illustrated in FIG. 5, the area map creation device 11 includes a measurement instruction unit 31, a reception unit 32, an area map creation unit 33, and a cell area adjustment unit 34.

  The measurement instruction unit 31 instructs the eNodeB 14 to create a failure occurrence area map in accordance with the operation of the operator. At this time, the measurement instruction unit 31 instructs the eNodeB 14 for a measurement period for creating a failure occurrence area map.

The receiving unit 32 receives area map creation information including location information and a failure factor from the eNodeB 14.
The area map creation unit 33 receives a measurement completion message from the eNodeB 14 and creates a failure occurrence area map based on the position information received by the reception unit 32 when the measurement period instructed to the eNodeB 14 has elapsed. The area map creation unit 33 creates a failure occurrence area map by plotting the received position information on the map.

  The cell area adjustment unit 34 adjusts the cell area of the eNodeB 14 based on the failure occurrence area map created by the area map creation unit 33 so that no communication failure occurs in the wireless terminal 16.

  For example, the cell area adjustment unit 34 generates a cell area adjustment map obtained by dividing the created failure occurrence area map into predetermined blocks (small sections). The cell area adjustment unit 34 determines whether or not the communication failure frequency (number of position information plotted in the small section) in the small section of the generated cell area adjustment map exceeds a predetermined threshold. When the communication failure frequency exceeds a predetermined threshold, the cell area adjustment unit 34 plots the cell formed by the eNodeB 14 on the cell area adjustment map. In the cell area adjustment map in which the cells are plotted, the cell area adjustment unit 34 specifies the closest cell from the small section where the communication failure frequency exceeds a predetermined threshold, and the specified cell includes the small section. ENodeB 14 is controlled.

  FIG. 6 is a block diagram of the eNodeB. As shown in FIG. 6, the eNodeB 14 includes a measurement instruction receiving unit 41, a communication quality acquisition unit 42, a wireless terminal extraction unit 43, a location information acquisition unit 44, a location information storage unit 45, a storage device 46, a failure detection unit 47, and A transmission unit 48 is provided.

The measurement instruction receiving unit 41 receives a measurement instruction for a failure occurrence area map from the area map creation device 11.
The communication quality acquisition unit 42 acquires communication quality from all the wireless terminals 16 belonging to the subordinate.

The wireless terminal extraction unit 43 extracts wireless terminals 16 having communication quality that does not satisfy the predetermined quality.
The position information acquisition unit 44 periodically requests the wireless terminal 16 extracted by the wireless terminal extraction unit 43 to transmit the position information. Further, the position information acquisition unit 44 receives the position information transmitted by the wireless terminal 16 in response to the position information transmission request.

Further, the position information acquisition unit 44 changes the cycle of the position information transmission request based on the difference between the previously acquired position information and the currently received position information or the communication quality of the wireless terminal 16.
The location information storage unit 45 stores the location information of the wireless terminal 16 acquired by the location information acquisition unit 44 in the storage device 46. The position information storage unit 45 overwrites and stores the position information for each wireless terminal 16 from which the position information has been acquired. Accordingly, the position information storage unit 45 stores the latest position information for each wireless terminal 16.

The failure detection unit 47 detects a communication failure of the wireless terminal 16 and acquires a failure factor.
When a failure is detected by the failure detection unit 47, the transmission unit 48 includes the latest location information stored in the storage device 46 of the wireless terminal 16 in which the communication failure is detected, and the failure acquired by the failure detection unit 47. Area map creation information including the factor is transmitted to the area map creation device 11.

FIG. 7 is a block diagram of the wireless terminal. The wireless terminal 16 includes a reception unit 51, a position information acquisition unit 52, and a transmission unit 53.
The receiving unit 51 receives a transmission request for position information from the eNodeB 14.

  When the receiving unit 51 receives a position information transmission request, the position information acquiring unit 52 acquires its own position information. For example, the position information acquisition unit 52 acquires the latitude and longitude in which it exists by GPS.

The transmission unit 53 transmits the position information acquired by the position information acquisition unit 52 to the eNodeB 14.
FIG. 8 is a sequence diagram of the area map creation system when no communication failure occurs.

  [Step S11] The measurement instruction unit 31 of the area map creation device 11 instructs the eNodeB 14 to create a failure area map. At this time, the measurement instruction unit 31 notifies the eNodeB 14 of the measurement period instructed by the operator.

  [Step S12] The measurement instruction receiving unit 41 of the eNodeB 14 receives the measurement instruction from the area map creation device 11. When receiving the measurement instruction, the measurement instruction receiving unit 41 starts the measurement period timer α, and sets a value (described in detail below) smaller than the measurement period transmitted together with the measurement instruction in the measurement period timer α.

  [Step S13] The communication quality acquisition unit 42 of the eNodeB 14 acquires the communication quality of all terminals belonging to the subordinate. For example, the communication quality acquisition unit 42 acquires transmission power and BLER values of all the wireless terminals 16 belonging to the subordinate.

  [Step S14] The wireless terminal extraction unit 43 of the eNodeB 14 extracts wireless terminals 16 that do not satisfy the predetermined communication quality based on the communication quality acquired by the communication quality acquisition unit 42.

[Step S15] The location information acquisition unit 44 of the eNodeB 14 starts the reporting cycle timer β corresponding to each of the wireless terminals 16 extracted in Step S14.
When the wireless terminal 16 that has not been extracted last time is extracted this time, the position information acquisition unit 44 sets an initial value for the reporting cycle timer β of the wireless terminal 16. For example, the position information acquisition unit 44 sets the initial report timer value in the report cycle timer β so as to count 10 seconds.

The position information acquisition unit 44 sets the report timer value based on steps S23 and S24 to the report cycle timer β when passing through steps S23 and S24 described below.
[Step S16] The location information acquisition unit 44 of the eNodeB 14 detects the expiration of the report cycle timer β.

  [Step S17] The location information acquisition unit 44 of the eNodeB 14 sends a location information transmission request to the radio terminal 16 whose report cycle timer β has expired, extracted by the radio terminal extraction unit 43. The position information acquisition unit 44 makes a request for transmission of position information by, for example, a measurement control signal.

[Step S18] The receiving unit 51 of the wireless terminal 16 receives a request for transmitting position information from the eNodeB 14, and the position information acquiring unit 52 acquires position information on which it exists.
[Step S19] The transmission unit 53 of the wireless terminal 16 transmits the position information acquired by the position information acquisition unit 52 to the eNodeB 14. The transmission part 53 transmits position information to eNodeB14 with a measurement report signal, for example.

  [Step S20] The location information acquisition unit 44 of the eNodeB 14 receives the location information of the wireless terminal 16. The position information storage unit 45 stores the position information received by the position information acquisition unit 44 in the storage device 46. The position information storage unit 45 overwrites and stores the position information for each wireless terminal.

  [Step S21] The transmitter 48 of the eNodeB 14 determines whether or not the measurement period timer α has expired. When the measurement period timer α expires, the transmission unit 48 proceeds to step S25. If the measurement period timer α has not expired, the transmission unit 48 proceeds to step S22.

  [Step S22] The position information acquisition unit 44 of the eNodeB 14 determines whether the difference between the position information stored in the storage device 46 last time and the position information stored in the current storage device 46 in Step S20 is a predetermined threshold value (hereinafter, referred to as “the threshold information”). It is determined whether it is smaller than (positional information threshold). Further, the position information acquisition unit 44 determines whether or not the communication quality of the wireless terminal 16 is smaller than a predetermined threshold (hereinafter referred to as a communication quality threshold) (the communication quality is better than the communication quality threshold).

  The positional information acquisition unit 44 proceeds to step S23 when the positional information difference is smaller than the positional information threshold or when the communication quality is better than the communication quality threshold. The positional information acquisition unit 44 proceeds to step S24 when the positional information difference is greater than or equal to the positional information threshold or when the communication quality is worse than the communication quality threshold.

[Step S23] The location information acquisition unit 52 of the eNodeB 14 increases the report timer value set in the report cycle timer β in step S15.
[Step S24] The location information acquisition unit 52 of the eNodeB 14 decreases the report timer value set in the report cycle timer β in step S15.

[Step S25] The transmission unit 48 of the eNodeB 14 transmits measurement completion to the area map creation device 11.
As described above, when the movement distance of the extracted wireless terminal 16 is small, the position information acquisition unit 52 increases the report timer value so that the frequency of reporting the position information decreases. On the other hand, when the movement distance of the extracted wireless terminal 16 is large, the report timer value is decreased so that the frequency of reporting location information increases. Further, when the communication quality of the extracted wireless terminal 16 is good, the location information acquisition unit 52 increases the report timer value so that the frequency of reporting location information is reduced. On the other hand, when the communication quality of the extracted wireless terminal 16 is poor, the report timer value is reduced so that the frequency of reporting location information increases.

  Thereby, when a communication failure occurs, the position information acquisition unit 52 can acquire position information closer to the position where the communication failure actually occurs. Also, by reducing the reporting frequency, the processing burden on the system can be reduced. Note that a plurality of position information threshold values and communication quality threshold values may be provided in stages, and the report timer value may be changed correspondingly.

FIG. 9 is a sequence diagram of the area map creation system when a communication failure occurs.
[Step S31] It is assumed that a communication failure has occurred in the wireless terminal 16 when the wireless terminal 16, the eNodeB 14, and the area map creation device 11 are performing the processing shown in FIG.

[Step S32] The failure detection unit 47 of the eNodeB 14 detects a communication failure of the wireless terminal 16 and acquires a failure factor.
[Step S33] The transmission unit 48 of the eNodeB 14 transmits area map creation information including the failure factor acquired by the failure detection unit 47 and the location information of the wireless terminal 16 stored in the storage device 46 to the area map creation device 11 ( Trouble report).

  FIG. 10 is a diagram showing a failure occurrence area map. The receiving unit 32 of the area map creation device 11 receives area map creation information including the location information of the wireless terminal 16 where the communication failure has occurred and the failure factor from the eNodeB 14. Based on the location information of the area map creation information received by the receiving unit 32, the area map creation unit 33 creates a failure occurrence area map as shown in FIG.

  FIG. 11 is a first diagram showing a cell area adjustment map. In FIG. 11, cells A and B of the eNodeB 14 are shown. As shown in FIG. 11, the cell A is formed in the direction of the inclination θ with respect to the x-axis (latitude). FIG. 11 shows areas where communication failures occur frequently.

  The cell area adjustment map shown in FIG. 11 can be created by dividing the failure occurrence area map shown in FIG. 10 into small sections and plotting the cells A and B formed by the eNodeB 14.

  For example, the cell area adjustment unit 34 of the area map creation device 11 receives the position information of the eNodeB 14 and the position information of the centers of the cells A and B formed by the eNodeB 14 from the eNodeB 14. Thereby, the cell area adjustment unit 34 can calculate in which direction and in what size the cells A and B are formed as shown in FIG. The cell area adjustment unit 34 can plot the calculated cells A and B on the failure occurrence area map divided into small sections to create a cell area adjustment map as shown in FIG.

Note that the communication failure frequent occurrence region shown in FIG. 11 corresponds to the failure occurrence location shown in FIG. Further, the intersection of the x-axis and the y-axis in FIG. 11 is a position where the eNodeB 14 exists.
FIG. 12 is a second diagram illustrating the cell area adjustment map. The cell area adjustment unit 34 of the area map creation device 11 adjusts the cells A and B of the eNodeB 14 so that the communication failure frequent occurrence area is eliminated. For example, the cell area adjustment unit 34 adjusts the cell area of the eNodeB 14 so that the cell area of the eNodeB 14 includes a frequent occurrence region of communication failure. Specifically, the cell area adjustment unit 34 adjusts the cell area of the eNodeB 14 by changing the direction, radius, or tilt angle of the cells A and B.

  In the example of FIG. 12, the cell area adjustment unit 34 sets the direction of the cell A to θ-α with respect to the x axis (latitude) so that the cell A closest to the frequent communication failure region includes the frequent communication failure region. The eNodeB 14 is controlled so as to have an inclination of. Or the cell area adjustment part 34 can also adjust the cell area of eNodeB14 so that the radius of the cell A may become large so that the cell A nearest to the frequent occurrence area of a communication failure may contain the frequent occurrence area of a communication failure.

FIG. 13 is a sequence diagram of cell area adjustment.
[Step S41] The measurement instructing unit 31 of the area map creating apparatus 11 starts the measurement period timer γ. The measurement instruction unit 31 sets the measurement period instructed by the operator in the measurement period timer γ.

  [Step S42] The measurement instruction unit 31 of the area map creation device 11 instructs the eNodeB 14 to create a failure area map. At this time, the measurement instruction unit 31 notifies the eNodeB 14 of the measurement period instructed by the operator. Step S42 corresponds to step S11 in FIG.

  [Step S43] The measurement instruction receiving unit 41 of the eNodeB 14 receives the measurement instruction from the area map creation device 11. When receiving the measurement instruction, the measurement instruction receiving unit 41 starts the measurement period timer α and sets a value smaller than the measurement period transmitted together with the measurement instruction in the measurement period timer α.

  The measurement period timer α is set to a value smaller than the measurement period of the measurement period timer γ. This is because the eNodeB 14 returns the measurement completion of the following step S48 to the area map creation device 11 before the area map creation device 11 starts creating the area map due to the expiration of the measurement period timer γ. Step S43 corresponds to step S12 in FIG.

  [Step S44] It is assumed that a communication failure has occurred in the wireless terminal A under the control of the eNodeB 14. The transmission unit 48 of the eNodeB 14 transmits area map creation information including the failure factor acquired by the failure detection unit 47 and the location information of the wireless terminal A stored in the storage device 46 to the area map creation device 11.

  [Step S45] It is assumed that a communication failure has occurred in the wireless terminal B under the control of the eNodeB 14. The transmission unit 48 of the eNodeB 14 transmits area map creation information including the failure factor acquired by the failure detection unit 47 and the location information of the wireless terminal B stored in the storage device 46 to the area map creation device 11.

  [Step S46] It is assumed that a communication failure has occurred in the wireless terminal C under the control of the eNodeB 14. The transmission unit 48 of the eNodeB 14 transmits area map creation information including the failure factor acquired by the failure detection unit 47 and the location information of the wireless terminal C stored in the storage device 46 to the area map creation device 11.

Steps S44 to S46 correspond to step S33 in FIG.
[Step S47] The transmitter 48 of the eNodeB 14 determines whether or not the measurement period timer α has expired. If the measurement period timer α has expired, the transmission unit 48 proceeds to step S48. If the measurement period timer α has not expired, the transmission unit 48 proceeds to step S44.

[Step S48] The transmission unit 48 of the eNodeB 14 transmits measurement completion to the area map creation device 11. Step S48 corresponds to step S25 in FIG.
[Step S49] The measurement period timer γ of the area map creation device 11 expires.

  [Step S50] The area map creation unit 33 of the area map creation device 11 receives the notification of measurement completion from the eNodeB 14 in step S48, and creates the area map when the measurement period timer γ expires in step S49. For example, the area map creation unit 33 plots the location of the failure on the map as shown in FIG. 10 based on the position information of the area map creation information received from the eNodeB 14.

  [Step S51] The cell area adjustment unit 34 of the area map creation device 11 divides the area map created by the area map creation unit 33 into small sections and creates a cell area adjustment map. The cell area adjustment unit 34 calculates the frequency of communication failures (the number of communication failures) in each small section.

  [Step S52] The cell area adjustment unit 34 of the area map creation device 11 determines whether or not the communication failure frequency in the small section exceeds a predetermined threshold. The cell area adjustment unit 34 determines that the small section where the communication failure frequency exceeds a predetermined threshold is the communication failure frequent occurrence region illustrated in FIGS. 11 and 12.

  When the communication failure frequency in the small section exceeds the predetermined threshold, the cell area adjustment unit 34 proceeds to step S53. If the communication failure frequency in the small section does not exceed the predetermined threshold, the cell area adjustment unit 34 ends the process.

  [Step S53] The cell area adjustment unit 34 of the area map creation device 11 plots the cells formed by the eNodeB 14 on the cell area adjustment map. The cell area adjustment unit 34 receives, from the eNodeB 14, the position of the eNodeB 14 and the position information of the center of the cell formed by the eNodeB 14, and specifies in which direction and in what size the cell of the eNodeB 14 is formed. be able to.

[Step S54] The cell area adjustment unit 34 of the area map creation device 11 identifies the cell closest to the communication failure frequent occurrence area.
[Step S55] The cell area adjustment unit 34 of the area map creation device 11 controls the eNodeB 14 so that the communication failure frequent occurrence area is included in the specified cell.

[Step S56] The cell area adjustment unit 34 of the area map creation device 11 instructs the eNodeB 14 to adjust the cell.
When the area map creation device 11 issues a cell adjustment instruction, the area map creation device 11 proceeds to the process of step S41 again, and acquires position information of the occurrence of communication failure after the cell adjustment. That is, the area map creation device 11 performs cell adjustment by feedback processing so that the communication failure frequency in the small section does not exceed a predetermined threshold.

  Thus, the eNodeB 14 periodically acquires the position information of the wireless terminal 16 and stores it in the storage device 46. When the eNodeB 14 detects a communication failure of the wireless terminal 16, the eNodeB 14 transmits area map creation information including the latest location information of the wireless terminal 16 stored in the storage device 46 and the failure factor to the area map creation device 11. The area map creation device 11 receives the area map creation information from the eNodeB 14 and plots the position information included in the area map creation information on the map.

  Thereby, the position information transmitted to the area map creation device 11 is the position information immediately before the communication failure of the wireless terminal 16 occurs, and can be regarded as the position information of the wireless terminal 16 when the communication failure occurs. The area map creation device 11 can create a failure occurrence area map indicating a position where a communication failure has occurred.

  In addition, since the eNodeB 14 changes the period for acquiring the extracted location information of the wireless terminal 16, it is possible to acquire location information closer to the location where the actual communication failure has occurred. In addition, the processing burden on the system can be reduced.

  Further, the area map creation device 11 receives a failure factor from the eNodeB 14. Accordingly, the area map creation unit 33 of the area map creation device 11 can also display the failure factor in the failure occurrence area map. As a result, the operator can easily identify the location where the communication failure has occurred and the cause of the failure.

  Further, the failure detection unit 47 of the eNodeB 14 can acquire the time when the communication failure occurs, and the transmission unit 48 can also transmit the time including the time in the area map creation information. Thereby, the area map creation unit 33 of the area map creation device 11 can also display the position and time of occurrence of the communication failure on the failure occurrence area map.

  Note that the RNC 12 or the BTS 13 may have the function of the eNodeB 14 shown in FIG. In this case, the area map creation device 11 can issue a measurement instruction to the RCN 12 or the BTS 13, and the RNC 12 or BTS 13 acquires the location information of the wireless terminal 15 in the same manner as the eNodeB 14 and creates the area map in the area map creation device 11. Information can be sent. Then, the area map creation device 11 can create a failure occurrence area map based on the area map creation information received from the RNC 12 or the BTS 13. The RNC 12 acquires the position information of the wireless terminal 15 via the BTS 13.

  Further, the CN device that is a higher-level device of the RNC 12 or the eNodeB 14 and controls them may have the function of the eNodeB 14 illustrated in FIG. In this case, the area map creation device 11 can issue a measurement instruction to the CN device, and the CN device acquires the location information of the wireless terminal in the same manner as the eNodeB 14 and transmits the area map creation information to the area map creation device 11. can do. The area map creation device 11 can create a failure occurrence area map based on the area map creation information received from the CN device. The CN device acquires the location information of the wireless terminals 15 and 16 via the RNC 12 and the BTS 13 or via the eNodeB 14.

  The area map creation device 11 can also specify a measurement target. For example, a measurement instruction can be given to any of the RNC 12, the BTS 13, the eNodeB 14, and the CN device.

  Cell area adjustment may be optional. For example, the cell area adjustment unit 34 of the area map creation device 11 may create a cell area adjustment map in accordance with an operator's instruction and control the eNodeB 14.

  Next, a third embodiment will be described in detail with reference to the drawings. In the third embodiment, the eNodeB stores a plurality of pieces of position information for each wireless terminal in a storage device, and estimates the position where the communication failure of the wireless terminal has occurred from the stored pieces of position information.

  FIG. 14 is a block diagram of an eNodeB according to the third embodiment. As illustrated in FIG. 14, the eNodeB 14 includes a position information storage unit 61, a storage device 62, and a position information estimation unit 63. Other functions are the same as those in FIG. 6, and detailed description thereof is omitted.

  The location information storage unit 61 stores the location information of the wireless terminal 16 acquired by the location information acquisition unit 44 in the storage device 62. The position information storage unit 61 stores a plurality of pieces of position information in the storage device 62 by the FIFO (First In First Out) method for each wireless terminal 16 from which the position information has been acquired.

  FIG. 15 is a diagram illustrating a data configuration example of the storage device. In FIG. 15, a plurality of pieces of position information of the wireless terminals A to C are stored. The wireless terminals A to C are wireless terminals extracted by the wireless terminal extraction unit 43.

  The location information storage unit 61 stores a plurality of location information of the wireless terminals A to C acquired by the location information acquisition unit 44 in the storage device 62 by the FIFO method. In the example of FIG. 15, for example, A1, B1, and C1 are the newest position information, and An, Bn, and Cn are the oldest position information.

  When the failure detection unit 47 detects a communication failure of the wireless terminals A to C, the location information estimation unit 63 determines that the communication failure of the wireless terminals A to C is based on the plurality of location information stored in the storage device 62. Estimate the position where it occurred. The position information estimation unit 63 estimates the position where the communication failure of the wireless terminals A to C occurs using the interpolation polynomial.

  For example, it is assumed that the failure detection unit 47 detects a communication failure of the wireless terminal A. In this case, the position information estimation unit 63 estimates the position where the communication failure of the wireless terminal A has occurred from a plurality of pieces of position information of the wireless terminal A stored in the storage device 62 using an interpolation polynomial of Lagrange interpolation. .

  FIG. 16 is a diagram for explaining position estimation of occurrence of a failure. FIG. 16 shows latitudes A11 to A1n of the position information A1 to An of the wireless terminal A shown in FIG. The position information estimation unit 63 obtains an interpolation polynomial based on the latitudes A11 to A1n of the position information A1 to An, and obtains the latitude of the wireless terminal A when a communication failure occurs (time N). Similarly, the position information estimation unit 63 obtains the longitude of the wireless terminal A when a communication failure occurs (time N).

Thereby, the position information estimation unit 63 can estimate the position information when the communication failure of the wireless terminal A occurs.
When a failure is detected by the failure detection unit 47, the transmission unit 48 creates an area map of the location information of the wireless terminal A estimated by the location information estimation unit 63 and the failure factor acquired by the failure detection unit 47. Transmit to device 11.

  In this way, the eNodeB 14 stores a plurality of pieces of position information in the storage device 62 by the FIFO method, and estimates the position where the failure has occurred by the interpolation polynomial. Thereby, it is possible to create a failure occurrence area map that is closer to the actual position where the communication failure has occurred.

  The area map creation device 11 can also specify the number of pieces of position information stored in the storage device 62. The position information storage unit 61 stores the number of pieces of position information in accordance with instructions from the area map creation device 11 in the storage device 62.

(Supplementary note 1) In a base station that performs wireless communication with a wireless terminal,
A location information acquisition unit that periodically acquires location information of the wireless terminal;
A location information storage unit that stores the location information acquired by the location information acquisition unit in a storage device;
A communication failure detection unit for detecting a communication failure of the wireless terminal;
When the communication failure is detected by the communication failure detection unit, area map creation information including the latest location information stored in the storage device of the wireless terminal in which the communication failure is detected is transmitted to the area map creation device A transmitter to
A base station characterized by comprising:

(Additional remark 2) The communication quality acquisition part which acquires the communication quality of the said wireless terminal,
A wireless terminal extraction unit that extracts the wireless terminal of the communication quality that does not satisfy a predetermined quality,
The base station according to supplementary note 1, wherein the position information acquisition unit periodically acquires the position information of the wireless terminal extracted by the wireless terminal extraction unit.

  (Additional remark 3) The said positional information acquisition part changes the period which acquires the said positional information based on the difference of the said positional information acquired last time and the said positional information acquired this time, or the said communication quality of the said radio | wireless terminal. The base station according to appendix 2, characterized by:

(Additional remark 4) The said positional information storage part memorize | stores the said several positional information in the said memory | storage device by FIFO (First In First Out) system,
A position information estimation unit that estimates the position information of the wireless terminal when the communication failure is detected by an interpolation polynomial based on the plurality of position information stored in the storage device;
The base station according to appendix 2, wherein the transmission unit transmits the area map creation information including the location information estimated by the location information estimation unit to the area map creation device.

(Additional remark 5) In the radio | wireless control apparatus which controls a base station,
A location information acquisition unit that periodically acquires location information of the wireless terminal;
A location information storage unit that stores the location information acquired by the location information acquisition unit in a storage device;
A communication failure detection unit for detecting a communication failure of the wireless terminal;
When the communication failure is detected by the communication failure detection unit, the area map creation information including the latest location information stored in the storage device of the wireless terminal where the communication failure is detected is transmitted to the area map creation device. A transmitter to
A wireless control device comprising:

(Additional remark 6) In the core network apparatus which controls a radio | wireless control apparatus,
A location information acquisition unit that periodically acquires location information of the wireless terminal;
A location information storage unit that stores the location information acquired by the location information acquisition unit in a storage device;
A communication failure detection unit for detecting a communication failure of the wireless terminal;
When the communication failure is detected by the communication failure detection unit, the area map creation information including the latest location information stored in the storage device of the wireless terminal where the communication failure is detected is transmitted to the area map creation device. A transmitter to
A core network device characterized by comprising:

(Supplementary note 7) In an area map creation device for creating an area map,
A receiver that receives area map creation information including location information when a communication failure of a wireless terminal occurs from a base station, a wireless control device that controls the base station, or a core network device that controls the wireless control device;
An area map creation unit that plots the location information included in the area map creation information received by the reception unit on a map and creates a failure occurrence area map indicating a location where a communication failure has occurred;
An area map creating apparatus characterized by comprising:

  (Additional remark 8) It has further a cell area adjustment part which produces | generates the cell area adjustment map which divided | segmented the said failure area map created by the said area map creation part into a predetermined block, and plots the cell of the said base station, The area map creation device according to appendix 7.

  (Supplementary Note 9) The cell area adjustment unit determines whether or not the communication failure frequency in the block exceeds a predetermined threshold, and if the frequency exceeds a predetermined threshold, plots the cell of the base station and 9. The area map creating apparatus according to appendix 8, wherein the base station is controlled to include the block having the communication failure frequency in which a cell of the base station exceeds a predetermined threshold.

  (Supplementary note 10) The supplementary note 9, wherein the cell area adjustment unit controls the base station so that a cell closest to the block having the communication failure frequency exceeding a predetermined threshold includes the block. Area map creation device.

  (Supplementary Note 11) An instruction unit that instructs the base station, the wireless control device, or the core network device to transmit the location information of the wireless terminal until the communication failure frequency does not exceed a predetermined threshold. The area map creation device according to supplementary note 9, characterized by comprising:

DESCRIPTION OF SYMBOLS 1 Base station 1a Position information acquisition part 1b Position information storage part 1c Storage device 1d Communication failure detection part 1e Transmission part 2 Area map creation apparatus 2a Reception part 2b Area map creation part 3 Wireless terminal

Claims (8)

In a base station that performs wireless communication with a wireless terminal,
A location information acquisition unit that periodically acquires location information of the wireless terminal;
A location information storage unit that stores the location information acquired by the location information acquisition unit in a storage device;
A communication failure detection unit for detecting a communication failure of the wireless terminal;
When the communication failure is detected by the communication failure detection unit, the area map creation information including the latest location information stored in the storage device of the wireless terminal where the communication failure is detected is transmitted to the area map creation device. A transmitter to
A base station characterized by comprising: A communication quality acquisition unit for acquiring communication quality of the wireless terminal;
A wireless terminal extraction unit that extracts the wireless terminal of the communication quality that does not satisfy a predetermined quality,
The base station according to claim 1, wherein the position information acquisition unit periodically acquires the position information of the wireless terminal extracted by the wireless terminal extraction unit.   The position information acquisition unit changes a period for acquiring the position information based on a difference between the position information acquired last time and the position information acquired this time or the communication quality of the wireless terminal. The base station according to claim 2. The location information storage unit stores a plurality of the location information in the storage device by a FIFO (First In First Out) method,
A position information estimation unit that estimates the position information of the wireless terminal when the communication failure is detected by an interpolation polynomial based on the plurality of position information stored in the storage device;
The base station according to claim 2, wherein the transmission unit transmits the area map creation information including the location information estimated by the location information estimation unit to the area map creation device. In a radio control device that controls a base station,
A location information acquisition unit that periodically acquires location information of the wireless terminal;
A location information storage unit that stores the location information acquired by the location information acquisition unit in a storage device;
A communication failure detection unit for detecting a communication failure of the wireless terminal;
When the communication failure is detected by the communication failure detection unit, the area map creation information including the latest location information stored in the storage device of the wireless terminal where the communication failure is detected is transmitted to the area map creation device. A transmitter to
A wireless control device comprising: In the core network device that controls the wireless control device,
A location information acquisition unit that periodically acquires location information of the wireless terminal;
A location information storage unit that stores the location information acquired by the location information acquisition unit in a storage device;
A communication failure detection unit for detecting a communication failure of the wireless terminal;
When the communication failure is detected by the communication failure detection unit, the area map creation information including the latest location information stored in the storage device of the wireless terminal where the communication failure is detected is transmitted to the area map creation device. A transmitter to
A core network device characterized by comprising: In an area map creation device that creates an area map,
A receiver that receives area map creation information including location information when a communication failure of a wireless terminal occurs from a base station, a wireless control device that controls the base station, or a core network device that controls the wireless control device;
An area map creation unit that plots the location information included in the area map creation information received by the reception unit on a map and creates a failure occurrence area map indicating a location where a communication failure has occurred;
An area map creating apparatus characterized by comprising:   8. The apparatus according to claim 7, further comprising a cell area adjustment unit that generates a cell area adjustment map obtained by dividing the failure occurrence area map created by the area map creation unit into predetermined blocks and plots cells of the base station. The area map creation device described.

Images