JP4730532B2 - Wireless access system, network management device, program, and quality management method - Google Patents

Description

  The present invention relates to communication quality management in a mobile communication network, and more particularly to a technique for determining whether or not the communication quality of a radio cell is good using a mobile terminal.

  In mobile communication networks that provide communication services over a wide area such as mobile phones, generally, the physical quality of the radio link at each point is measured offline using measurement equipment installed in a dedicated electric vehicle (radio wave measurement vehicle) Furthermore, the communication area is designed and optimized by conducting radio wave propagation simulation. An example of quality measurement using an electric vehicle is described in Patent Document 1.

  Usually, the measurement items by the electric vehicle are the position of the measurement point, the reception intensity of the pilot channel from the radio base station at the measurement point, and the chip energy versus the interference power density at the measurement point. If the reception strength of the pilot channel from the radio base station is not sufficient, the mobile terminal cannot establish synchronization with the radio base station and is out of the communication service area.

  Even if the reception strength of the pilot channel is secured to some extent, if there is a large amount of interference from other radio base stations or other mobile terminals, there is a possibility that the mobile terminal will fail in handover or the like, causing communication problems. high. Such a situation is called pilot solution. As disclosed in Non-Patent Document 1, one definition of pilot solution is shown by equation (1).

  In Equation (1), Ec is the received chip energy in a mobile communication network based on the CDMA system (hereinafter referred to as “CDMA mobile communication network”). Io is the interference power density. CPICH RSCP is a reception power (Received Signal Code Power) of a common pilot channel (Common Pilot Channel).

  Cross statistical analysis is performed based on the physical quality of the radio line measured by the electric vehicle to determine whether or not pilot pollution occurs in the radio area. Cross-statistic analysis is a method of collecting and analyzing data by paying attention to the correspondence between a plurality of items obtained from measurement data.

  When detecting the pilot solution, the two conditions in the equation (1) are items used for the cross statistical analysis. It is determined that a pilot solution has occurred when the frequency that two conditions of Ec / Io <−14 dB and (CPICH RSCP)> − 95 dBm are satisfied at the same time is high.

  Specifically, first, Ec / Io and CPICH RSCP are measured several times at different times and locations within the area, and the respective measurement results are acquired. Then, the ratio of the number of times that the measurement result satisfies the two conditions in Equation (1) simultaneously with respect to the total number of measurements is calculated. When the ratio exceeds a predetermined threshold value, it can be determined that pilot dilution has occurred.

  One of the purposes of managing the communication quality of a radio cell is to continuously provide a stable communication service by reducing the area that is out of service area and the area where pilot pollution occurs as much as possible.

  In particular, the CDMA mobile communication network has a feature that the area coverage ratio changes according to the amount of interference caused by surrounding traffic. Therefore, in order to ensure good communication, many techniques for performing area quality evaluation or changing operation parameters using traffic measured for each radio cell have been disclosed (see Patent Documents 2 to 4). .

  Patent Document 2 discloses a method of optimizing the service area by controlling the antenna tilt angle of the radio base station according to the measured traffic volume. Patent Document 3 discloses a technique for calculating an area loss evaluation by calculating a call loss rate and a communication quality deterioration rate based on an average value and a variance value of measured traffic. Patent Document 4 discloses a method of optimizing the required transmission power of a radio base station based on the measured traffic distribution.

  These technologies enable macro quality evaluation and area design optimization in units of radio cells based on actual measurements.

  However, the points that can be measured by the electric vehicle are limited on general roads, and it is practically impossible to perform measurement at all places where the mobile terminal may be used. Also, it is often difficult to measure by electric vehicle in places where there are many mobile terminals. For this reason, even if the techniques disclosed in Patent Documents 2 to 4 are used, it is not always possible to ensure sufficient communication quality in a place where there are many mobile terminals in the radio cell. In addition, since measurement takes time and labor costs are limited, the frequency of measurement by an electric vehicle is usually at most once a month.

  Therefore, the area design based on the measurement by the electric vehicle may not necessarily reflect the line quality at the latest time in the area where many subscribers in the wireless cell gather. As described above, the conventional measurement by the electric vehicle has a geographical problem that the measurement point is limited and a frequency problem that the measurement frequency is not sufficient.

  On the other hand, in the mobile communication network, the propagation loss changes gradually with time due to the influence (shadowing) of the building shadow on the radio propagation path. In a CDMA mobile communication network, outer loop transmission that adaptively resets a target block error rate and adjusts transmission power accordingly in order to compensate for changes in propagation loss caused by shadowing or movement of a mobile terminal. Power control is performed (see Non-Patent Document 3).

  In a CDMA mobile communication network, generally, strong interference (multipath fading) occurs in a short time as the mobile terminal moves due to interference between electromagnetic waves passing through a plurality of propagation paths. Therefore, normally, in a CDMA mobile communication network, high-speed closed loop transmission power control is also performed to compensate for this multipath fading.

  High-speed closed-loop transmission power control is intended to compensate for severe attenuation in a short period of time, and therefore has a shorter control cycle than outer-loop transmission power control. The time interval of outer loop transmission power control is about 1 second, while the time interval of high-speed closed loop transmission power control is about 0.67 milliseconds.

  The degree of shadowing is important environmental information that affects the traffic capacity that can be accommodated in the radio cell and the frequency of handover. In general, an appropriate shadowing amount is assumed at the design stage of a radio area, and system performance related to traffic capacity and handover frequency is estimated based on the assumption.

  However, since this does not reflect actual shadowing in the radio cell, errors may occur in the estimated system performance. Therefore, it is desirable to acquire a number of actual measurement values that can be statistically analyzed at a frequency at which the latest situation can be grasped at a location where the mobile terminal in the wireless cell may exist. In other words, sufficient radio link quality measurement is desired both geographically and frequently in system performance evaluation.

  Physical quality information such as Ec / Io of the pilot channel, RSCP, and propagation loss between the base station and the mobile terminal can be selected or reselected by a general mobile terminal during a call in addition to the electric vehicle. It can be measured for control and periodically notified to the radio base station via the control channel (see Non-Patent Document 2).

  Therefore, Patent Document 5 discloses a method in which a radio base station automatically controls the transmission power of a pilot channel to avoid pilot volume so that Ec / Io received by a mobile terminal becomes constant. According to this, it is possible to perform measurement at a place where measurement cannot be performed with an electric vehicle, and it is possible to increase the measurement frequency.

  In addition, general mobile terminals used by subscribers include mobile terminals equipped with a positioning function based on GPS (Global Positioning System). Therefore, when combined with a function for measuring the physical quality of a radio link, It is also possible to perform measurement at a mobile terminal.

Therefore, Patent Document 6 discloses a method of optimizing transmission power and beam in a radio base station based on abnormal call disconnection in a mobile terminal and statistics of positioning information at that time. According to this, it is possible to reduce adverse effects by optimization based on statistics and ensure good communication quality.
Japanese Utility Model Publication No. 6-18979 JP-A-9-154168 JP 2001-217786 A JP 2002-77985 A JP 2001-358650 A JP 2001-2111474 A Jukka Lempi & aumlinen, Matti Manninen, “UMTS Radio Network Planning, Optimization and QoS Management”, Kluwer Academic Publishers, pp. 138-142, 2003. 3GPP TS 25.331, “Radio Resource Control (RRC) Protocol Specification”, Sec. 10.3.7.3.2005. Harris Holma, Anti Toskala, “WCDMA for UMTS”, John Wiley & Sons, pp. 190-197, 2002.

  The transmission power of the pilot channel described above is an important parameter that affects the shape of the radio area. In the conventional method using the measurement result of the mobile terminal disclosed in Patent Document 5, the quality of the communication is determined based on the measurement value of the mobile terminal without performing wide-area optimization by the radio wave propagation simulator, and the transmission power is determined from the determination result. Will be adaptively controlled. Therefore, in this conventional method, there is a risk of an adverse effect that a dead zone or a pilot pollution zone is generated at another point when the radio cell is viewed as a whole.

  In addition, according to the conventional method disclosed in Patent Document 6 in which an electric vehicle is substituted by a general mobile terminal, many mobile terminals in a radio cell are used to acquire measurement results necessary for statistical processing. It is necessary to have a positioning function and a quality control function linked to it. Moreover, it is necessary for a general mobile terminal to have a positioning function and a dedicated quality control function. For this reason, with this conventional method, sufficient measurement results cannot be obtained until mobile terminals equipped with positioning functions and quality control functions in software or the like are widely spread to many users, and the communication quality of the radio cell is appropriately set. There was a problem that it could not be judged.

  An object of the present invention is to provide a system that appropriately determines the normality of the communication quality of a radio cell using information related to the communication quality of a radio channel measured at a point where a mobile terminal can exist.

In order to achieve the above object, the wireless access system of the present invention provides:
A radio access system accommodating a mobile terminal having a function of measuring and notifying communication quality of a radio line,
A control device that aggregates the communication quality notified from a plurality of mobile terminals for each radio cell and generates histogram information;
A management device that acquires the histogram information generated by the control device and determines normality of communication for each wireless cell by statistical processing based on a plurality of quality indexes from the histogram information.

  Therefore, according to the present invention, the control device aggregates the communication quality of the radio channel acquired by each mobile terminal for each radio cell to generate the histogram information, and the management device uses the statistics based on the plurality of quality indexes. Since analysis is performed by processing, it is possible to make an appropriate normality judgment reflecting communication quality at a point where the mobile terminal actually exists by using information from a general mobile terminal that is actually used. Further, it is not necessary to add a positioning function and a quality management function linked to the positioning function to the mobile terminal, and appropriate normality determination can be performed without waiting for the spread of a specific mobile terminal. In addition, a highly accurate determination result can be obtained by statistical processing and analysis using a plurality of quality indexes.

Further, the mobile terminal measures the communication quality of a plurality of items and notifies the control device,
The control device aggregates the communication quality of a plurality of items notified from the mobile terminal for each radio cell, generates histogram information of a plurality of items, and notifies the management device,
The management device may determine the normality of communication for each radio cell by performing cross statistical analysis on the histogram information of the plurality of items based on a quality index for each of the plurality of items.

  Therefore, according to this, since the histogram information is analyzed by cross statistics based on a plurality of quality indexes and the normality of each radio cell is determined, a highly accurate determination result can be obtained.

Further, the mobile terminal measures the chip energy versus interference power density and pilot channel received power as the communication quality and notifies the control device,
The control apparatus notifies the management apparatus of the histogram information generated by summing up the chip energy versus interference power density and the pilot channel reception power notified from the mobile terminal for each radio cell,
The management apparatus uses the first to third thresholds as the quality index, and based on the histogram information, the chip energy versus interference power density is less than the first threshold and the pilot channel received power is the second threshold. It may be determined that the communication in the radio cell whose frequency exceeds the third threshold has deteriorated.

Further, the mobile terminal measures a propagation loss of a radio line as the communication quality and notifies the control device,
The control device totalizes the propagation loss notified from the mobile terminal for each radio cell, generates the histogram information and notifies the management device,
The management apparatus uses the fourth and fifth thresholds as the quality index, and based on the histogram information, performs communication in a radio cell in which the frequency that the propagation loss exceeds the fourth threshold exceeds the fifth threshold. It may be determined that the quality has deteriorated.

  Therefore, according to this, the control device statistically processes the propagation loss value acquired by each mobile terminal for each radio cell to generate histogram information, and the management device converts the histogram information into a plurality of quality indexes (thresholds). Since the analysis is performed based on this, a highly accurate determination result can be obtained by statistical processing and analysis using a plurality of quality indexes.

Further, the mobile terminal notifies the control device of the propagation loss measured in the outer loop transmission power control,
The control device holds the propagation loss notified from the mobile terminal in time series for each communication session, and calculates shadowing as a residual between the propagation loss and the time-series moving average of the propagation loss, Generate the histogram information by counting the standard deviation of the shadowing for each radio cell and notify the management device,
The management apparatus uses the sixth and seventh thresholds as the quality indicator, and based on the histogram information, the frequency at which the standard deviation of the shadowing exceeds the sixth threshold exceeds the seventh threshold. It may be determined that the quality of communication in the network has deteriorated.

  Therefore, according to this, the control apparatus statistically processes the propagation loss information acquired by each mobile terminal for each radio cell to generate histogram information of the shadowing estimation standard deviation. Since the analysis is performed based on the quality index (threshold value) and the normality of each wireless cell is determined, a highly accurate determination result can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, the normality judgment which reflected the communication quality in the point where a mobile terminal actually exists can be performed using the information from the general mobile terminal actually used. Further, it is not necessary to add a positioning function and a quality management function linked to the positioning function to the mobile terminal, and appropriate normality determination can be performed without waiting for the spread of a specific mobile terminal. In addition, a highly accurate determination result can be obtained by statistical processing and analysis using a plurality of quality indexes.

  Embodiments for carrying out the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a system configuration diagram showing a configuration of a radio access network as a first embodiment. Referring to FIG. 1, the radio access network includes radio base stations 11, 21, 31, 41, a base station control device 50, and a network management device 60.

  The radio base stations 11, 21, 31, and 41 are provided in hexagonal radio cells 10, 20, 30, and 40, respectively. Within the radio cell 10, a radio base station 11 accommodates mobile terminals 12, 13, and 14. Within the radio cell 20, a radio base station 21 accommodates mobile terminals 22, 23 and 24. Within the radio cell 30, a radio base station 31 accommodates mobile terminals 32, 33, and 34. Within the radio cell 40, the radio base station 41 accommodates mobile terminals 42, 43, 44.

  The wireless base station 11 is connected to the base station controller 50 via the wired link 15, the wireless base station 21 via the wired link 25, the wireless base station 31 via the wired link 35, and the wireless base station 41 via the wired link 45. It is connected.

  The base station control device 50 performs processing such as traffic transfer to the mobile communication core network 70 in the subordinate radio cells 10, 20, 30, 40, radio resource allocation control, handover control, failure management, and communication quality management. . Then, the base station control device 50 transfers the failure information and the communication quality measurement result acquired by these processes to the network management device 60.

  The network management device 60 is based on information notified from the base station control device 50 and operation by the administrator, etc., provisioning of operation parameters in each device in the mobile communication system, network failure monitoring, communication service quality monitoring, etc. Perform network management.

  The mobile communication core network 70 is an exchange network that forms a mobile communication network together with a radio access network.

  The network management device 60 manages the state of each device, each wired line, and wireless line in the wireless access network.

  FIG. 2 is a block diagram showing a logical configuration of the mobile terminal in the first embodiment. Since all the mobile terminals 12-14, 22-24, 32-34, 42-44 shown in FIG. 1 have the same configuration, the mobile terminal 24 will be described here. Referring to FIG. 2, the mobile terminal 24 includes a radio transceiver 100, a system abandonment information acquisition unit 101, a pilot channel reception power measurement unit 102, a chip energy versus interference power density measurement unit 103, a transmission power control unit 104, a radio channel physics. It has a quality measurement processing unit 105, a radio cell selection / reselection processing unit 106, a voice call unit 107, and a data communication unit 108.

  The voice call unit 107 provides a voice call function, and the data communication unit 108 provides a data communication function. The mobile terminal 24 transmits / receives a signal input / output to / from the voice communication unit 107 by voice communication or a signal input / output to / from the data communication unit 108 by data communication to / from the radio base station 21. Prior to communication such as voice call or data communication, the mobile terminal 24 needs to establish synchronization with the radio base station 21 and register itself with the mobile communication network.

  The system notification information acquisition unit 101 acquires system notification information notified from the radio base station. The system broadcast information is information necessary for the mobile terminal 24 to register itself with the mobile communication network, and includes information on pilot channel transmission power from the radio base station 21.

  The pilot channel received power measuring unit 102 measures the received power of the pilot channel from the nearest radio base station group. The value of the received power is provided to the radio channel physical quality measurement processing unit 105 as information necessary for radio cell selection and reselection control accompanying movement. The radio wave propagation loss in the radio channel between the radio base station and the mobile terminal is obtained by the difference between the pilot channel transmission power notified by the system broadcast information and the reception power of the pilot channel.

  The chip energy-to-interference power density ratio measurement unit 103 measures the chip energy-to-interference power density ratio (Ec / Io) as an index indicating the degree of physical quality degradation due to interference from other stations, and measures the radio channel physical quality. Provided to the processing unit 105.

  The radio channel physical quality measurement processing unit 105 collects information from the system broadcast information acquisition unit 101, the pilot channel received power measurement unit 102, and the chip energy to interference power density ratio measurement unit 103, and transmits it according to the collected information. Processing related to power or radio cell selection or reselection is performed.

  The transmission power control unit 104 controls transmission power in accordance with an instruction from the radio channel physical quality measurement processing unit 105.

  The radio cell selection / reselection processing unit 106 controls selection or reselection of a radio cell in accordance with an instruction from the radio channel physical quality measurement processing unit 105.

  For transmission power control or radio cell selection / reselection processing, the radio channel physical quality measurement processing unit 105 sends the pilot channel received power and chip energy versus interference power density to the radio base station 21 as the radio channel physical quality. Notify regularly.

  FIG. 3 is a block diagram illustrating a logical configuration of the base station control device according to the first embodiment. Referring to FIG. 3, the base station controller 50 includes a transceiver 200, a data transfer 201, a control signal processing unit 202, a communication quality measurement processing unit 203, an outer loop transmission power control unit 204, a cell selection / reselection control unit 205. A histogram generation unit 206, a call control unit 207, and an operation parameter setting unit 208.

  The data transfer unit 201 transfers data between the mobile terminal and the mobile communication core network 70 via the transceiver 200. The data transfer unit 201 inputs and outputs control signals related to the control of the radio access network among the signals transmitted and received by the transceiver 200 with the control signal processing unit 202. The control signal includes a control signal related to call processing, a control signal for setting or changing operation parameters, and a control signal related to notification of physical quality of a radio channel.

  The control signal processing unit 202 sends a call processing control signal to the call control unit 207, a control signal related to the operation parameter to the operation parameter setting unit 208, and a control signal related to notification of the physical quality of the radio channel to the histogram generation unit 206. And sort each.

  The logical and physical qualities of the radio access network are collected by the communication quality measurement processing unit 203 and sent to the cell selection / reselection control unit 205, the outer loop transmission power control unit 204, and the histogram generation unit 206.

  The cell selection / reselection control unit 205 performs cell selection and reselection processing using the communication quality information.

  The outer loop transmission power control unit 204 performs outer loop transmission power control processing using the communication quality information.

  The histogram generation unit 206 aggregates the physical quality of the radio channel notified from the mobile terminal or collected by the communication quality measurement processing unit 203 for each radio cell, and uses the network as a control signal of histogram information together with the logical communication quality. The management device 60 is notified.

  The call control unit 207 transmits and receives control signals to and from the mobile terminal and the mobile communication core network 70 via the control signal processing unit 202 to perform call control.

  The operation parameter setting unit 208 transmits and receives control signals to and from the mobile terminal and the mobile communication core network 70 via the control signal processing unit 202 to set and change operation parameters.

  FIG. 4 is a block diagram illustrating a configuration of the network management device according to the first embodiment. Referring to FIG. 4, the network management device 60 includes a transceiver 300, a data transfer unit 301, a failure display unit 302, a monitoring information input unit 303, a communication quality monitoring unit 304, a communication quality statistics storage unit 305, and a communication quality target value storage. A unit 306, a histogram analysis unit 307, a wireless area design unit 308, and an operation parameter setting unit 309.

  The data transfer unit 301 transmits and receives control signals related to network management with the base station controller 50. Examples of control signals related to network management include network monitoring information such as failure information and communication quality measurement results notified from the base station control device 50, operation parameters for each device notified to the base station control device 50, and the like. There is. The data transfer unit 301 transfers the control signal of the network monitoring information from the base station control device 50 to the monitoring information input unit 303. In addition, an operation parameter control signal from the operation parameter setting unit 309 is transmitted to the base station controller 50.

  The monitoring information input unit 303 analyzes the control signal from the data transfer unit 301 and notifies the network quality monitoring information to the communication quality monitoring unit 304. The network monitoring information includes histogram information generated by the histogram generation unit 206 of the base station control device 50.

  When the network monitoring information is input via the monitoring information input unit 303, the communication quality monitoring unit 304 stores the network monitoring information in the communication quality statistics storage unit 305 and determines whether there is a network failure based on the network monitoring information. If there is a failure, the communication quality monitoring unit 304 causes the failure display unit 302 to display the failure content.

  Further, the communication quality monitoring unit 304 saves the communication quality information in the communication quality statistics storage unit 305 at regular time intervals regardless of whether there is a failure.

  Further, the communication quality monitoring unit 304 also displays the content of the abnormality or failure on the failure display unit 302 when notified from the histogram analysis unit 307 that an abnormality or failure has been detected.

  The histogram analysis unit 307 displays the quality indicators such as physical quality information of the radio channel for each radio cell stored as histogram information in the communication quality statistics storage unit 305 and various thresholds stored in the communication quality target value storage unit 306. It is used to estimate the quality of communication service of each wireless cell and determine the normality of communication of each wireless cell.

  If an abnormality has occurred in the radio cell from the estimation result and the cause of the abnormality is clear, the histogram analysis unit 307 sets the operation parameter to the operation parameter setting unit 204 so as to eliminate or mitigate the abnormality. Direct change.

  The operation parameter setting unit 309 holds and manages various operation parameters, and changes them according to instructions from the histogram analysis unit 307. At that time, the operational parameter setting unit 309 sends a control signal for changing the operational parameter to the base station controller 50.

  Next, the operation of the radio access network of this embodiment will be described.

  FIG. 5 is a flowchart illustrating communication quality monitoring processing performed by the network management device according to the first embodiment. This operation is performed by the communication quality monitoring unit 304 of the network management device 60. Referring to FIG. 5, when the network monitoring information is input (step 501), the communication quality monitoring 304 determines whether or not failure information is included in the network monitoring information (step 502).

  If the failure information is included, the communication quality monitoring unit 304 outputs and displays the failure information on the failure display unit 302 (step 503). After the failure information is output to the failure display unit 302 or when the failure information is not included in the network monitoring information, the communication quality monitoring unit 304 stores the communication quality information in the communication quality statistics storage unit 305. The data is output to the unit 305 (step 504), and the process is terminated. That is, the communication quality monitoring unit 304 stores the communication quality information in the communication quality statistics storage unit 305 regardless of whether or not the failure information is included in the network monitoring information.

  As shown in FIG. 5, when the communication quality monitoring unit 304 periodically stores communication quality information in the communication quality statistics storage unit 305, histogram information is accumulated in the communication quality statistics storage unit 305. This histogram information is analyzed by the histogram analysis unit 307.

  FIG. 6 is a diagram illustrating an example of histogram information acquired by the histogram analysis unit according to the first embodiment. The histogram of FIG. 6 shows the distribution of measured power versus chip energy versus interference power density (Ec / Io) and RSCP in a given wireless cell.

  Here, it is assumed that presence / absence of pilot solution is determined based on the criterion of Expression (1), and a threshold value for this is stored in the communication quality target value storage unit 306. In FIG. 6, the region satisfying the expression (1) is a region indicated by hatching where Ec / Io <−14 dB and RSCP> −95 dBm. If the frequency of this area is higher than a predetermined threshold value, the histogram analysis unit 307 determines that pilot volume is occurring.

  FIG. 7 is a flowchart illustrating a cross statistical analysis process performed by the network management device according to the first embodiment. This operation is performed by the histogram analysis unit 307 of the network management device 60. Referring to FIG. 7, first, the histogram analysis unit 307 selects a target radio cell (step 601), and from the communication quality target value storage unit 306, the Ec / Io upper limit value T1, the RSCP lower limit value T2, and the pilot solution. A rate threshold T3 is acquired (step 602). In the formula (1), T1 = −14 dB and T2 = −95 dBm.

  Next, the histogram analysis unit 307 acquires the total number of times N1 of histogram information measurement (step 603). Further, the histogram analysis unit 307 acquires a measurement frequency X that satisfies Ec / Io <T1 and RSCP> T2 (step 604). Then, the histogram analysis unit 307 determines whether X / N1> T3 is satisfied (step 605).

  If X / N1> T3, the histogram analysis unit 307 determines that the pilot solution has occurred in the target radio cell, and notifies the communication quality monitoring unit 304 of the detection of the pilot solution abnormality (step 606). .

  When it is determined in step 605 that X / N1> T3 is not satisfied, or when the processing of step 606 is completed, the histogram analysis unit 307 returns to step 601 and selects the next radio cell. When the analysis is performed for all the wireless cells, the histogram analysis unit 307 ends the series of processes.

  If the ratio (X / N1) of the number X of simultaneously satisfying the threshold value T1 and the threshold value T2 with respect to the total number of measurement times N1 is sufficiently large (in this case, greater than the threshold value T3), pilot pollution occurs in the radio cell. It is estimated that

  Thus, according to the present embodiment, each mobile terminal sends the acquired physical quality of the radio channel to the base station control device 50, and the base station control device 50 sends the physical quality information notified from the mobile terminal. The histogram information is generated by aggregation for each radio cell, and transmitted to the network management device 60. The network management device 60 analyzes the histogram information by cross statistics based on a plurality of quality indexes, and determines the normality of each radio cell. judge. Since information from a general mobile terminal that is actually used is used, appropriate normality determination reflecting physical quality at a point where the mobile terminal actually exists can be performed. In addition, since the mobile terminal only acquires and notifies the physical quality of the radio channel by the existing function originally provided in the mobile terminal, there is no need to add a positioning function and a quality management function linked to the positioning function to the mobile terminal. Thus, proper normality determination can be performed without waiting for the spread of a specific mobile terminal. In addition, since statistical processing is performed and analysis is performed using a plurality of quality indexes, the accuracy of the determination result can be increased, and the possibility that the radio cell is adversely affected by control based on the determination result can be reduced.

  In this embodiment, the physical quality of the radio channel measured by the mobile terminal is used. However, it is also possible to determine the communication quality of the radio cell using the logical communication quality with the same configuration and method.

(Second Embodiment)
Next, an example is shown in which normality is determined from the radio wave propagation loss between the radio base station and the mobile terminal as the physical quality of the radio channel. The radio access network of the second embodiment has the same configuration as that of the first embodiment shown in FIG.

  FIG. 8 is a diagram illustrating an example of histogram information of radio channel propagation loss acquired in the second embodiment. FIG. 8 shows, as a measurement frequency, how much radio channel loss measured per unit time in a certain radio cell is included in which region of 10 dB width.

  If the threshold T4 for detecting environmental degradation due to a weak electric field is 140 dB, the number of times included in the region 410 equal to or greater than T4 = 140 dB indicates degradation. When the number of times that the wireless line loss is equal to or greater than the threshold (propagation loss upper limit) T4 exceeds the (electric field degradation rate threshold) threshold T5, it is determined that the weak electric field strength region is wide.

  The histogram generation unit 206 of the base station control device 50 of the present embodiment generates the above-described histogram information.

  FIG. 9 is a flowchart illustrating statistical analysis processing performed by the network management device according to the second embodiment. This operation is performed by the histogram analysis unit 307 of the network management device 60. Referring to FIG. 9, first, the histogram analysis unit 307 selects a target radio cell (step 621), and acquires threshold values T4 and T5 from the communication quality target value storage unit 306 (step 622).

  Next, the histogram analysis unit 307 acquires the total number of times N2 of histogram information measurement (step 623). Furthermore, the histogram analysis unit 307 acquires the measurement frequency Y that satisfies propagation loss> T4 (step 624). Then, the histogram analysis unit 307 determines whether or not Y / N2> T5 is satisfied (step 625).

  If Y / N2> T5, the histogram analysis unit 307 determines that the weak electric field strength region of the target wireless cell is wider than the reference, and notifies the communication quality monitoring unit 304 to that effect (step 626).

  When it is determined in step 625 that Y / N2> T5 is not satisfied, or when the processing in step 626 is completed, the histogram analysis unit 307 returns to step 621 and selects the next radio cell. When the analysis is performed for all the wireless cells, the histogram analysis unit 307 ends the series of processes.

  Thus, according to the present embodiment, each mobile terminal sends the acquired propagation loss value to the base station controller 50, and the base station controller 50 wirelessly transmits the propagation loss information notified from the mobile terminal. The histogram information is generated by aggregation for each cell, and is transmitted to the network management device 60. The network management device 60 analyzes the histogram information based on a plurality of quality indexes (thresholds), and determines the normality of each radio cell. To do. Although cross statistics are not used in the present embodiment, statistical processing is performed in the same manner as in the first embodiment, and analysis is performed using a plurality of quality indexes (threshold values T4 and T5).

  Note that the propagation loss value is extremely large, and the value of the propagation loss is not notified from a mobile terminal that is completely out of the service area. On the other hand, the abnormal termination due to the movement of the mobile terminal out of service area is complemented by collecting and counting the reasons for abnormal termination of communication at the base station controller in the wireless access network and notifying the network management device. It is good as well.

(Third embodiment)
Next, an example is shown in which normality is determined from the shadowing amount between the radio base station and the mobile terminal as the physical quality of the radio channel. The wireless access network of the third embodiment has the same configuration as that of the first embodiment shown in FIG.

  FIG. 10 is a diagram illustrating an example of a radio link loss and a shadowing estimation value acquired from a certain mobile terminal in the third embodiment. FIG. 10 exemplifies a temporal change in the radio link loss when the mobile terminal moves outward from approximately the center of the radio cell. A gentle attenuation change with a change in distance and a sudden change due to the effect of shadowing are superimposed.

  The temporal change in the radio channel loss shown in the upper part of FIG. 10 is obtained from a notification that the outer loop transmission power control unit 204 of the base station control device 60 performs about once per second by the outer loop transmission power control.

  For the measured value 430 (solid line in the upper part of FIG. 10) of the radio link loss, the moving average 420 (shown in the upper part of FIG. 10) showing a gradual attenuation trend with a change in distance is obtained by performing a moving average calculation in a window of about 20 seconds. (Dotted line) is extracted. Then, when a residual 440 (lower part in FIG. 10) between the measured value 430 and the moving average 420 is obtained, an estimated shadowing amount is obtained.

  FIG. 11 is a histogram showing the distribution of the standard deviation of the shadowing estimation amount. It can be said that a communication session with a high standard deviation of shadowing is greatly deteriorated by shadowing. Therefore, the standard deviation of the shadowing estimation value is obtained for each communication session, and the distribution is totaled in a histogram. The communication in the region 450 where the standard deviation exceeds a predetermined threshold (upper limit value of the shadowing estimation standard deviation) T6. If the number of sessions exceeds a predetermined threshold (shadowing amount deterioration rate threshold) T7, it can be determined that the deterioration due to shadowing exceeds the reference. In FIG. 11, the threshold T6 = 14 dB for detecting environmental degradation due to shadowing.

  The histogram generation unit 206 of the base station control device 50 of the present embodiment generates the above-described histogram information.

  FIG. 12 is a flowchart illustrating statistical analysis processing performed by the network management device according to the third embodiment. This operation is performed by the histogram analysis unit 307 of the network management device 60. Referring to FIG. 12, first, the histogram analysis unit 307 selects a target radio cell (step 641), and acquires threshold values T6 and T7 from the communication quality target value storage unit 306 (step 642).

  Next, the histogram analysis unit 307 acquires the total number of times N3 of histogram information measurement (step 643). Further, the histogram analysis unit 307 acquires the measurement frequency Z that satisfies the shadowing estimation standard deviation> T6 (step 644). Then, the histogram analysis unit 307 determines whether or not Z / N3> T7 is satisfied (step 645).

  If Z / N3> T7, the histogram analysis unit 307 determines that the degradation due to the shadowing of the target radio cell is greater than the reference, and notifies the communication quality monitoring unit 304 accordingly (step 646).

  When it is determined in step 645 that Z / N3> T7 is not satisfied, or when the processing of step 646 ends, the histogram analysis unit 307 returns to step 641 and selects the next radio cell. When the analysis is performed for all the wireless cells, the histogram analysis unit 307 ends the series of processes.

  Thus, according to the present embodiment, each mobile terminal sends the acquired propagation loss value to the base station controller 50, and the base station controller 50 wirelessly transmits the propagation loss information notified from the mobile terminal. Summing up for each cell to obtain a shadowing estimation standard deviation, generating histogram information and transmitting it to the network management device 60, the network management device 60 analyzing the histogram information based on a plurality of quality indicators (thresholds), The normality of each radio cell is determined. Although cross statistics are not used in the present embodiment, statistical processing is performed in the same manner as in the first embodiment, and analysis is performed using a plurality of quality indexes (threshold values T6 and T7). Further, by reflecting the obtained standard deviation and dispersion amount of shadowing in the wireless area design, it is possible to predict the wireless system performance with higher accuracy.

  In the present embodiment, the standard deviation is used as an example, but it is substantially the same if a variance value is used instead.

1 is a system configuration diagram showing a configuration of a radio access network as a first embodiment. FIG. It is a block diagram which shows the logical structure of the mobile terminal in 1st Embodiment. It is a block diagram which shows the logical structure of the base station control apparatus in 1st Embodiment. It is a block diagram which shows the structure of the network management apparatus in 1st Embodiment. It is a flowchart which shows the communication quality monitoring process which the network management apparatus of 1st Embodiment performs. It is a figure which shows an example of the histogram information which the histogram analysis part of 1st Embodiment acquires. It is a flowchart which shows the cross statistical analysis process which the network management apparatus of 1st Embodiment performs. It is a figure which shows an example of the histogram information of the radio link propagation loss acquired in 2nd Embodiment. It is a flowchart which shows the statistical analysis process which the network management apparatus of 2nd Embodiment performs. In 3rd Embodiment, it is a figure which shows an example of the radio | wireless line loss and shadowing estimated value acquired from a certain mobile terminal. It is a histogram which shows distribution of the standard deviation of a shadowing estimation amount. It is a flowchart which shows the statistical analysis process which the network management apparatus of 3rd Embodiment performs.

Explanation of symbols

10, 20, 30, 40 Wireless cell 11, 21, 31, 41 Wireless base station 12-14, 22-24, 32-34 Mobile terminal 15, 25, 35, 45 Wired link 50 Base station controller 60 Network management device DESCRIPTION OF SYMBOLS 70 Mobile core network 100 Radio | wireless transmitter / receiver 101 System idle information acquisition part 102 Pilot channel reception power measurement part 103 Chip energy with respect to interference power density measurement part 104 Transmission power control part 105 Radio | wireless channel physical quality measurement process part 106 Processing unit 107 Voice communication unit 108 Data communication unit 200 Transmitter / receiver 201 Data transfer 202 Control signal processing unit 203 Communication quality measurement processing unit 204 Outer loop transmission power control unit 205 Cell selection / reselection control unit 206 Histogram generation unit 207 Call control unit 208 Operation parameter setting Unit 300 transceiver 301 data transfer unit 302 failure display unit 303 monitoring information input unit 304 communication quality monitoring unit 305 communication quality statistical storage unit 306 communication quality target value storage unit 307 histogram analysis unit 308 wireless area design unit 309 operation parameter setting unit 410 , 450 region 501-504, 601-606, 621-626, 641-646 step T4, T6 threshold

Claims (16)

A radio access system accommodating a mobile terminal having a function of measuring and notifying communication quality of a radio line,
A control device that aggregates the communication quality notified from a plurality of mobile terminals for each radio cell and generates histogram information;
A management device that acquires the histogram information generated by the control device, and determines the normality of communication for each radio cell by statistical processing based on a plurality of quality indicators from the histogram information;
The mobile terminal measures the communication quality of a plurality of items and notifies the control device,
The control device aggregates the communication quality of a plurality of items notified from the mobile terminal for each radio cell, generates histogram information of a plurality of items, and notifies the management device,
The management device, the plurality items histogram information of the by cross statistical analysis based on the quality indicator for each of a plurality of items, wherein the determining the normality of communication for each wireless cell, no line access system. The mobile terminal measures the signal-to-interference ratio and pilot channel received power as the communication quality and notifies the control device,
The control device notifies the management device of the histogram information generated by counting the signal-to-interference ratio and the pilot channel reception power notified from the mobile terminal for each radio cell,
The management apparatus uses the first to third thresholds as the quality index, and based on the histogram information, the signal-to-interference ratio is less than the first threshold and the pilot channel received power exceeds the second threshold. wireless access systems of the frequency is determined that the communication in a radio cell has been exceeded the third threshold value is decreased quality, according to claim 1. A radio access system accommodating a mobile terminal having a function of measuring and notifying communication quality of a radio line,
A control device that aggregates the communication quality notified from a plurality of mobile terminals for each radio cell and generates histogram information;
A management device that acquires the histogram information generated by the control device, and determines the normality of communication for each radio cell by statistical processing based on a plurality of quality indicators from the histogram information;
The mobile terminal measures a propagation loss of a radio line as the communication quality and notifies the control device,
The control device totalizes the propagation loss notified from the mobile terminal for each radio cell, generates the histogram information and notifies the management device,
The management apparatus uses the fourth and fifth thresholds as the quality index, and based on the histogram information, performs communication in a radio cell in which the frequency that the propagation loss exceeds the fourth threshold exceeds the fifth threshold. It determines that decreased quality, no line access system. A radio access system accommodating a mobile terminal having a function of measuring and notifying communication quality of a radio line,
A control device that aggregates the communication quality notified from a plurality of mobile terminals for each radio cell and generates histogram information;
A management device that acquires the histogram information generated by the control device, and determines the normality of communication for each radio cell by statistical processing based on a plurality of quality indicators from the histogram information;
The mobile terminal notifies the control device of the propagation loss measured in outer loop transmission power control,
The control device holds the propagation loss notified from the mobile terminal in time series for each communication session, and calculates shadowing as a residual between the propagation loss and the time-series moving average of the propagation loss, Generate the histogram information by counting the standard deviation of the shadowing for each radio cell and notify the management device,
The management apparatus uses the sixth and seventh thresholds as the quality indicator, and based on the histogram information, the frequency at which the standard deviation of the shadowing exceeds the sixth threshold exceeds the seventh threshold. communication in is determined to have decreased quality, no line access system. A network management device for a radio access network accommodating a mobile terminal having a function of measuring and notifying communication quality of a radio line,
A communication quality target value storage unit storing a plurality of quality indicators in advance;
A communication quality statistics storage unit storing histogram information in which the communication quality from a plurality of mobile terminals is tabulated for each radio cell;
The histogram information stored in the communication quality statistics storage unit is acquired, and from the histogram information, statistical processing based on the plurality of quality indicators stored in the communication quality target value storage unit is performed for each radio cell. A histogram analysis unit for determining normality of communication,
In the histogram information, communication quality of a plurality of items is tabulated for each radio cell,
The quality indicator is defined for at least each of the communication quality of the plurality of items,
The histogram analysis section, by a cross statistical analysis using the quality index and the histogram information of a plurality of items, determining the normality of communication for each of the radio cell network management device. In the histogram information, the signal-to-interference ratio and the pilot channel received power are tabulated for each radio cell,
The communication quality target value storage unit stores first to third thresholds as the quality index,
The histogram analysis unit, based on the histogram information, is a radio in which the signal-to-interference ratio is less than the first threshold and the frequency at which the pilot channel received power exceeds the second threshold exceeds the third threshold. The network management device according to claim 5 , wherein the network management device determines that communication in the cell has deteriorated in quality. A network management device for a radio access network accommodating a mobile terminal having a function of measuring and notifying communication quality of a radio line,
A communication quality target value storage unit storing a plurality of quality indicators in advance;
A communication quality statistics storage unit storing histogram information in which the communication quality from a plurality of mobile terminals is tabulated for each radio cell;
The histogram information stored in the communication quality statistics storage unit is acquired, and from the histogram information, statistical processing based on the plurality of quality indicators stored in the communication quality target value storage unit is performed for each radio cell. A histogram analysis unit for determining normality of communication,
In the histogram information, propagation loss of the wireless line is tabulated for each wireless cell,
The communication quality target value storage unit stores fourth and fifth threshold values as the quality index,
The histogram analysis section, from said histogram information, determines that the communication in a radio cell the frequency of the propagation loss exceeds the fourth threshold value has exceeded the fifth threshold value is decreased quality, network management device. A network management device for a radio access network accommodating a mobile terminal having a function of measuring and notifying communication quality of a radio line,
A communication quality target value storage unit storing a plurality of quality indicators in advance;
A communication quality statistics storage unit storing histogram information in which the communication quality from a plurality of mobile terminals is tabulated for each radio cell;
The histogram information stored in the communication quality statistics storage unit is acquired, and from the histogram information, statistical processing based on the plurality of quality indicators stored in the communication quality target value storage unit is performed for each radio cell. A histogram analysis unit for determining normality of communication,
The histogram information includes, for each radio cell, a standard deviation of shadowing calculated as a residual between the propagation loss for each communication session measured by outer loop transmission power control and the time-series moving average of the propagation loss. Have been aggregated,
The communication quality target value storage unit stores sixth and seventh thresholds as the quality index,
The histogram analysis section, from the histogram information, determines that the communication in a radio cell the frequency of the standard deviation of the shadowing exceeds the sixth threshold value exceeds said seventh threshold value is decreased quality, network Management device. A program for causing a computer of a network management device of a radio access network that accommodates a mobile terminal having a function of measuring and notifying communication quality of a radio line to execute it,
Processing to store a plurality of quality indicators in advance;
A process of storing histogram information in which the communication quality from a plurality of the mobile terminals is tabulated for each radio cell;
From the histogram information, causing the computer to execute processing for determining normality of communication for each wireless cell by statistical processing based on the plurality of quality indicators,
In the histogram information, communication quality of a plurality of items is tabulated for each radio cell,
The quality indicator is defined for at least each of the communication quality of the plurality of items,
By cross statistical analysis using the quality index and the histogram information of a plurality of items, determining the normality of communication for each of the radio cell, the program. In the histogram information, the signal-to-interference ratio and the pilot channel received power are aggregated for each radio cell,
First to third threshold values are defined as the quality indicators,
From the histogram information, the quality of communication in a radio cell in which the signal-to-interference ratio is less than the first threshold and the frequency at which the pilot channel received power exceeds the second threshold exceeds the third threshold is degraded. The program according to claim 9 , wherein the program is determined to be performed. A program for causing a computer of a network management device of a radio access network that accommodates a mobile terminal having a function of measuring and notifying communication quality of a radio line to execute it,
Processing to store a plurality of quality indicators in advance;
A process of storing histogram information in which the communication quality from a plurality of the mobile terminals is tabulated for each radio cell;
From the histogram information, causing the computer to execute processing for determining normality of communication for each wireless cell by statistical processing based on the plurality of quality indicators,
In the histogram information, the propagation loss of the radio line is totaled for each radio cell,
Fourth and fifth threshold values are defined as the quality indicators,
Wherein the histogram information to determine a communication in a radio cell the frequency of the propagation loss exceeds the fourth threshold value has exceeded the fifth threshold value is decreased quality program. A program for causing a computer of a network management device of a radio access network that accommodates a mobile terminal having a function of measuring and notifying communication quality of a radio line to execute it,
Processing to store a plurality of quality indicators in advance;
A process of storing histogram information in which the communication quality from a plurality of the mobile terminals is tabulated for each radio cell;
From the histogram information, causing the computer to execute processing for determining normality of communication for each wireless cell by statistical processing based on the plurality of quality indicators,
The histogram information includes, for each radio cell, a standard deviation of shadowing calculated as a residual between the propagation loss for each communication session measured by outer loop transmission power control and the time-series moving average of the propagation loss. Aggregated,
Sixth and seventh thresholds are defined as the quality indicators,
Wherein the histogram information, determines that the communication in a radio cell the frequency of the standard deviation of the shadowing exceeds the sixth threshold value exceeds said seventh threshold value is lowered quality program. A quality management method in a radio access network accommodating a mobile terminal having a function of measuring and notifying the communication quality of a radio line,
Totalizing the communication quality notified from a plurality of mobile terminals for each radio cell to generate histogram information;
Determining the normality of communication for each wireless cell by statistical processing based on a plurality of quality indicators from the histogram information,
The mobile terminal measures the communication quality of a plurality of items and notifies the radio access network,
The radio access network generates a plurality of items of histogram information by counting the communication quality of a plurality of items notified from the mobile terminal for each radio cell,
Wherein the plurality of items histogram information of the by cross statistical analysis based on the quality indicator for each of a plurality of items, determining the normality of communication for each of the radio cells, quality control methods. The mobile terminal measures the signal-to-interference ratio and pilot channel received power as the communication quality and notifies the radio access network,
The radio access network aggregates the signal-to-interference ratio and the pilot channel received power notified from the mobile terminal for each radio cell, and generates the histogram information,
The first to third threshold values are used as the quality index, and from the histogram information, the frequency at which the signal-to-interference ratio is less than the first threshold value and the pilot channel received power exceeds the second threshold value is 14. The quality management method according to claim 13 , wherein it is determined that the communication in the radio cell exceeding the threshold of 3 has deteriorated. A quality management method in a radio access network accommodating a mobile terminal having a function of measuring and notifying the communication quality of a radio line,
Totalizing the communication quality notified from a plurality of mobile terminals for each radio cell to generate histogram information;
Determining the normality of communication for each wireless cell by statistical processing based on a plurality of quality indicators from the histogram information,
The mobile terminal measures a propagation loss of a radio line as the communication quality and notifies the radio access network,
The radio access network aggregates the propagation loss notified from the mobile terminal for each radio cell, generates the histogram information,
Using the fourth and fifth thresholds as the quality index, it is determined from the histogram information that the communication in the radio cell in which the frequency at which the propagation loss exceeds the fourth threshold exceeds the fifth threshold has deteriorated. to, quality management method. A quality management method in a radio access network accommodating a mobile terminal having a function of measuring and notifying the communication quality of a radio line,
Totalizing the communication quality notified from a plurality of mobile terminals for each radio cell to generate histogram information;
Determining the normality of communication for each wireless cell by statistical processing based on a plurality of quality indicators from the histogram information,
The mobile terminal notifies the radio access network of the propagation loss measured by outer loop transmission power control,
The radio access network holds the propagation loss notified from the mobile terminal in time series for each communication session, and calculates shadowing as a residual of the propagation loss and the time-series moving average of the propagation loss. The histogram information is generated by aggregating the standard deviation of the shadowing for each radio cell,
Using the sixth and seventh thresholds as the quality index, the quality of communication in a radio cell in which the frequency at which the standard deviation of shadowing exceeds the sixth threshold exceeds the seventh threshold is determined from the histogram information. and judges, quality control method was.

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