JP5689761B2 - Wireless communication network system and method of selecting physical cell identifier in the system - Google Patents

Description

  The present invention relates to a radio communication network system and a method for selecting a physical cell identifier in the system, and in particular, to select a physical cell identifier so that physical cell identifiers for identifying cells do not collide or cause confusion. The present invention relates to a cellular radio communication network system capable of performing the same and a method of selecting a physical cell identifier in the system.

  In general, a cellular radio communication network system is configured by installing a large number of base stations at some distance intervals using radio waves in the same frequency band in order to construct a communicable area. Since each of these base stations uses radio waves in the same frequency band, in order to be able to identify the station (cell) of the radio wave transmission source between adjacent stations and neighboring stations, Instead of transmission information subjected to modulation / demodulation by each wireless communication system, one of a plurality of types of physical patterns of transmission radio waves that are not dependent on the result of modulation / demodulation is assigned. For this reason, the cellular radio communication network system needs to be provided with a plurality of types of physical patterns of transmission radio waves as described above, and a channel configuration capable of constituting a plurality of types of radio wave transmission patterns in each cellular radio communication system has been devised. Yes.

  Increasing the number of patterns of the above-described plural types of radio wave transmission patterns means that a lot of radio resources are consumed, and therefore the types are limited. The number of types is about one hundred to several hundreds in a general cellular radio communication system. The numbers assigned to these plural types of radio wave transmission patterns in order of 0, 1, 2, 3, 4, 5, 6,... Are referred to herein as physical cell identifiers (PCI). And The mobile station can receive the radio wave from the base station and specify the PCI from the radio wave transmission pattern.

  For example, even in the LTE (Long Term Evolution) system of 3GPP (3rd Generation Partnership Project), which is a 3.9th generation wireless communication system, one or more mobile stations are accommodated in a base station called a cell. The physical cell identifier PCI is used to identify the wireless communication area. The physical cell identifier PCI is used in a mobile station (UE) to measure received power from neighboring cells. There are 504 types of PCI, and the mobile station (UE) can measure up to 504 cells and measure the received power. As the number of types of PCI increases, problems with PCI as described later are less likely to occur. However, as the number of types of PCI increases, more radio resources are required. Generally, since the number of cells in the cellular radio communication network system is larger than 504, PCI is repeatedly used, and there are a plurality of cells having the same PCI.

  When the mobile station switches the connection from the currently connected cell to the adjacent cell (handover), it receives the PCI of the handover destination candidate, but since there are many cells having the same PCI in the entire system, only the information on the PCI is received. In this case, it is not possible to uniquely identify neighboring cells. Therefore, the base station has a table for converting PCI to a unique ID (Cell Global Identifier: CGI) in the entire system, and converts the PCI reported from the mobile station into CGI at the base station or The conversion table is transferred from the station to the mobile station, and the mobile station converts the PCI into CGI. As a result, the mobile station can specify a handover destination cell, and can start necessary processing for handover between the currently connected base station and the handover destination base station. Since this conversion table describes neighboring cells as a list, this table is called a Neighbor Cell Relations (NCR) list.

  The PCI allocation for each cell needs to be done so as not to cause the two problems described below.

  The first problem is PCI collision. That is, when coverage is overlapped between cells having the same PCI, a mobile station starts from a neighboring cell (referred to as cell Y) having the same PCI during communication with the current connected cell (referred to as cell X). Will also receive radio waves and receive radio wave interference. However, the mobile station cannot identify the cell Y having the same PCI as the cell X, and cannot hand over to the cell Y. This is a problem that the multipath radio wave from the cell X is added to the radio wave from the cell X, and the radio wave intensity of the cell X is measured if the radio wave intensity is stronger than the actual one.

  The second problem is PCI confusion. That is, when a certain cell (referred to as cell K) overlaps with multiple cells (referred to as cell L and cell M) having the same PCI, the base station side uniquely converts PCI to CGI according to the NCR list. Therefore, when the PCI of the cell L is received, even if it can be correctly converted into the CGI of the cell L, even when the PCI of the cell M is received, it is converted into the CGI of the cell L. . In this case, the handover process of the mobile station that is going to be handed over from the cell K to the cell M is inappropriately processed from the cell K to the cell L, and the mobile station receives a radio wave with a strength that allows handover. The problem is that handover is made to a cell L that is not, and the handover fails. In general, only one CGI is described for one PCI in the NCR list, and handover to other cells having the same PCI always fails.

  When selecting a PCI for a new cell when constructing a new base station, the above two problems should be avoided. From the PCI allocation situation of the cells around the station location, the above-mentioned 2 The PCI that has cleared one problem is selected.

  One possible method for selecting a PCI of a new cell is to select a PCI to be set for the cell from the remaining PCI except for all the PCIs of the cell located within a radius of several kilometers from the position of the cell. It is a method. In addition to this method, a method of selecting a PCI in consideration of topography, a method of selecting a PCI by estimating the radio wave propagation status of each cell using a radio wave propagation simulator, and the like can be considered. However, it is not realistic that the estimation is 100% accurate, and even if PCI is selected by these methods, PCI collision or confusion may occur.

  The NCR list preferably reflects the radio wave condition around the cell, but the radio wave condition around the cell can be reflected by several means. For example, a method such as an automatic neighbor relation setting function (3GPP TS36.300, Section 22.3.2a Automatic Neighbor Relation Function) (ANR function) in the 3GPP LTE scheme is conceivable. In this method, when the mobile station detects a PCI that does not exist in the NCR list of the cell to which the mobile station is currently connected, the mobile station reads the broadcast information of the cell of the PCI, acquires the CGI therefrom, and is connected. The base station that reports to the cell adds a new PCI and CGI record to the NCR list of the cell.

  The NCR list created in this way can reflect the radio wave conditions around the cell to a sufficient extent for the purpose of handover if there is a sufficient amount of report from the mobile station. However, if there is a PCI cell (cell B) identical to that cell (cell A) in the vicinity, the mobile station cannot identify and report the cell B PCI, so cell A Cell B will not be added to the NCR list. In addition, when there are a plurality of cells (cell C and cell D) having the same PCI in the vicinity, only one cell (for example, a cell previously detected and reported by the mobile station) is included in the NCR list. Will be added.

  In the former case where cell B is not added to the NCR list of cell A, there is a situation where a PCI collision has occurred and the service is adversely affected, but from the NCR list created by the ANR function, I do not know the occurrence of. In the latter case, where only one cell of two cells is added to the NCR list, a station that has not been added to the NCR list cannot be handed over. Although it is highly probable that this has occurred, it cannot be known from the NCR list created by the ANR function. In addition, from the NCR list, it is possible to know the surrounding radio wave conditions, but it is not possible to know the presence or absence of occurrence of PCI collision and confusion.

  As a method for knowing whether or not a PCI collision has occurred, a method described in Patent Document 1 is known. In this method, a cell to which the mobile station is connected (referred to as cell E) is temporarily prevented from transmitting a reference signal for causing the mobile station to detect its own PCI. The reference signal of a peripheral cell having the same PCI as that of the cell E can be detected. According to this method, a PCI collision can be detected. As a method of knowing whether or not PCI confusion has occurred, there is also a method of causing the mobile station to read the broadcast information of the PCI cell and report the CGI for the PCI existing in the NCR list. By this method, the base station that has received the report can know whether or not PCI confusion has occurred by determining whether or not a plurality of CGIs are reported for the same PCI. A method of knowing whether or not these PCI collisions and confusions have occurred is realized by mounting a dedicated function in the base station or mobile station.

JP 2010-537479 A

3GPP TS 36.300 V10.2.0 (2010-12)

  The physical cell identifier (PCI) set for each cell of each base station constituting the cellular radio communication network system is limited in the types that can be set (one hundred to several hundred), and the same identifier is set at some distance interval. I have to set it. However, if the same identifier is set between adjacent base stations, problems such as PCI collision and PCI confusion occur, and one of them greatly affects the radio wave reception quality of the other.

  In addition, the PCI of each cell is not based on the radio wave condition in the field, but is generally studied and set so as to avoid PCI collision on the desk. However, when there is an unexpected radio wave situation, PCI collision or PCI confusion occurs. These problems can be avoided if there is a high radio wave propagation simulation technique or more man-hours for investigation, but in any case, a problem that a lot of cost is required is caused.

  In addition, as described in the prior art document, a method of detecting a PCI collision or a PCI confusion after setting a PCI in each cell has also been proposed. However, these methods vary depending on the system and the system operation method. This requires a lot of change, which causes a problem that a lot of cost is required.

  In view of the above-described problems in the conventional cellular radio communication network system as described above, the object of the present invention is to actually launch a radio wave or change radio parameters and start operation of the system. It is an object of the present invention to provide a wireless communication network system capable of selecting and setting a PCI that does not cause a collision or confusion, and a method for selecting a physical cell identifier in the system.

According to the present invention, there is provided a cellular radio communication network system including a plurality of radio base stations and a base station controller connected to the plurality of radio base stations and controlling the plurality of radio base stations. The radio base station accommodates one or a plurality of cells that are radio communication areas, and an NCR list in which one physical cell identifier and one cell global identifier are associated with each other. And an automatic neighbor relation setting processing means for performing an adjacent cell related NCR list setting process, wherein the base station control device centrally manages configuration information of a plurality of cells, and an adjacent cell related NCR. NCRDB for centrally managing the list, and managing and controlling the cell DB and NCRDB, and setting the physical cell identifier and the NCR list in the cell of the radio base station And a base station data management control unit that, the base station data management control means of the base station controller, the ability to create NCR list indicating neighbor cell relation of the cell according to the radio wave environment around the certain cell And when the function of creating the NCR list selects the physical cell identifier of the certain cell, it has already started to emit radio waves in the NCR list indicating the neighboring cell relationship of the created cell. The physical cell identifier of the cell included in the NCR list indicating the neighbor cell relationship of the selection target cell of the wireless base station is removed from the selection candidates of the physical cell identifier, and the physical cell identifier of the certain cell is selected . Depending on whether the physical cell identifier is a condition for removing the physical cell identifier from the candidate for selection of the physical cell identifier, or depending on the number of times the condition is met, a selection priority is given to the physical cell identifier, It is achieved by selecting a physical cell identifier of the certain cells in accordance with the selected priority.

  According to the present invention, PCI that does not cause PCI collision or confusion according to the radio wave environment in the actual operation setting after actually starting the emission of radio waves or changing various wireless parameters and starting the operation, Alternatively, it is possible to select a PCI that is unlikely to cause a PCI collision or confusion and set the selected PCI in a cell.

It is a block diagram which shows the structure of the cellular radio | wireless communication network system by one Embodiment of this invention. It is a block diagram which shows the structural example of the base station eNB. It is a block diagram which shows the structural example of the mobile station UE. It is a figure which shows the structural example of an NCR list. It is a figure explaining the process which the automatic adjacent relationship setting process part ANR adds a record to an NCR list. It is a sequence chart explaining the process in which the automatic adjacent relationship setting process part ANR adds a record to an NCR list. It is a flowchart explaining the processing operation which the radio | wireless communication network system in embodiment of this invention reselects a cell identifier. It is a figure explaining the example (the 1) of the update of the NCR list | wrist of the cell of a base station by automatic adjacent relationship setting process ANR. It is a figure explaining the example (the 2) of the update of the NCR list | wrist of the cell of the base station by automatic adjacent relationship setting process ANR. It is a flowchart explaining the operation | movement of the extraction process of PCI which should be avoided in the base station control apparatus EMS. It is a flowchart explaining the processing operation which resets PCI in a base station control apparatus EMS and a base station. It is a figure explaining the NCR list which cannot be acquired when temporary PCI has mixed PCI. It is a flowchart explaining the processing operation | movement of PCI reset when using some temporary PCI.

  Embodiments of a wireless communication network system according to the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a cellular radio communication network system according to an embodiment of the present invention.

  A cellular radio communication network system according to an embodiment of the present invention shown in FIG. 1 includes a plurality of radio base stations (hereinafter simply referred to as base stations and also referred to as eNBs) 20-1 to 20-4,. The mobile station (hereinafter referred to as UE) 30-1 to 30-5,... And a base station control device (hereinafter referred to as EMS) 10 that controls the base station.

  The base station eNB accommodates one or a plurality of cells that are radio communication areas. The EMS 10 is configured to include a base station control unit 100. The base station control unit 100 includes a cell database (cell DB) 102 that centrally manages configuration information of a plurality of cells, and neighbor cell relations (NCR). An NCR database (NCRDB) 103 that centrally manages the list, a base station data management control unit 101 that manages and controls the cell DB 102 and the NCRDB 103, and sets a physical cell identifier (PCI) and an NCR list in the eNB. It is configured.

  FIG. 2 is a block diagram illustrating a configuration example of the base station eNB. The eNBs 20-1 to 20-4 are configured to set a neighbor cell relation (NCR) list and a communication processing unit 202 that performs communication processing between the radio apparatus 201 that performs radio transmission and reception, the mobile station UE, and the like. An automatic neighbor relation setting processing unit (Automatic Neighbor Relation: ANR) 203 that performs a handover process and a handover processing unit 204 that performs a handover process between adjacent cells are configured. In addition, the eNB 20 holds NCR lists T01-1 to T01-3 for each cell.

  The communication processing unit 202 has a function of modulating digital data and converting it into a radio signal transmitted to the mobile station UE, demodulating a radio signal transmitted from the mobile station UE, and converting it into digital data. The base station eNB has one or a plurality of cells, and each cell holds one physical cell identifier PCI, one cell global identifier (CGI), and one NCR list. The physical cell identifier PCI is used for the purpose of measuring received power from neighboring cells in the mobile station UE. For example, there are 504 types of PCI, and in this case, the mobile station UE can identify up to 504 cells and measure the received power. As will be described later, problems with PCI are less likely to occur as the number of PCI types increases. However, as the number of PCI types increases, more radio wave resources are required. Therefore, in the embodiment of the present invention described here, the PCI type is set to 504. It's kind. Since the total number of cells in the system is greater than 504, the PCI is repeatedly used, and there are a plurality of cells having the same PCI.

  On the other hand, the cell global identifier CGI, which has nothing to do with the measurement of received power and can be provided with sufficient types, is unique to the cell. The NCR list indicates the correspondence between PCI and CGI within a limited range around the cell having the NCR list, and the base station eNB uses the NCR lists T01-1 to T01-3 by the handover processing unit 204. By referencing, a handover destination candidate cell can be uniquely identified from the received power intensity for each PCI reported from the mobile station UE. The automatic adjacency setting processing unit ANR203 performs setting processing of the NCR lists T01-1 to T01-3 by a method described later.

  FIG. 3 is a block diagram illustrating a configuration example of the mobile station UE. The mobile stations UE30-1 to UE30-5 (hereinafter also simply referred to as the mobile station UE30) include a radio apparatus 301 that performs radio transmission and reception, a communication processing unit 302 that performs communication processing with the base station eNB, and a PCI And a measurement processing unit 303 that measures received radio waves.

  The communication processing unit 302 has a function of demodulating a radio signal transmitted from the base station eNB and converting it into digital data, modulating digital data, and converting it into a radio signal transmitted to the base station eNB. In the mobile station UE30, the measurement processing unit 303 constantly monitors the radio wave reception quality for each PCI, and reports the radio station reception quality data for each PCI to the base station eNB via the communication processing unit 302 as necessary. Send a message.

  FIG. 4 is a diagram illustrating a configuration example of the NCR list. The NCR list T01 is a data table managed in units of cells, and the base station eNB holds as many cells as the cell itself has. Further, the base station control unit 100 of the base station control device EMS10 holds the NCR list of all the cells of the managed base station eNB in the NCRDB 103. The change of the NCR list in the base station eNB and the change of the NCR list in the base station control apparatus are mutually reflected by the notification message and are always synchronized.

  The data table of the NCR list shown in FIG. 4 associates a physical cell identifier (PCI), a cell global identifier (CGI), and handover (HO) information for efficient handover. A single record has a plurality of records. The handover (HO) information corresponds to communication destination information in a handover procedure between the base station eNB and the eNB to which the handover destination cell belongs.

  FIG. 5 is a diagram for explaining a process in which the automatic adjacency setting processing unit ANR 203 adds a record to the NCR list, which will be described next.

(1) When the mobile station UE30-1 detects the PCI of the cell B of the base station eNB20-2 during communication via the cell A of the base station eNB20-1 (here, # 10 is assumed as an example), the cell A The information of the detected PCI (PCI # 10) is sent among the measurement information periodically sent to the base station eNB20-1 having The base station eNB20-1 having the cell A confirms whether or not the sent PCI # 10 is in the NCR list, and if it does, nothing is done (step S1).

(2) If the PCI # 10 is not in the NCR list in the above confirmation, a request is issued to the mobile station UE to acquire the PCI # 10 CGI information. The mobile station UE that has received the request reads the CGI (for example, CGI = 211100) of the cell B from the broadcast information issued by the base station eNB 20-2 having the cell B (steps S2 and S3).

(3) The mobile station UE reports the read CGI (211100) of the cell B to the base station eNB20-1 having the cell A. The base station eNB20-1 having the cell A adds the received PCI # 10 and CGI (211100) as a new record to the NCR list. In addition, the description about the process which acquires HO information using this CGI = 211100 is abbreviate | omitted (step S4).

  In the above-described processing, the mobile station UE has the cell B during communication with the base station eNB20-1 having the cell A because the radio wave reception range of either the cell A or the cell B or both becomes small. When the PCI (PCI # 10) of the base station eNB20-2 is not detected, the base station eNB20-1 having the cell A does not receive the PCI # 10 information from the UE. The ANR 203 of the base station eNB20-1 also performs processing for deleting such a PCI record that is not detected for a certain period of time or a PCI record with a small number of detections within a unit time from the NCR list. In addition, in the NCR list at the start of the processing described above, a PCI having no PCI overlap is set in the base station, and a record having the same PCI as the already included PCI is not added. Therefore, the NCR list maintains a state where there is no PCI overlap.

  FIG. 6 is a sequence chart for explaining processing in which the automatic adjacency setting processing unit ANR203 adds a record to the NCR list. The processing shown here is a sequence chart of the processing described with reference to FIG. In addition, each of S1-S4 shown in FIG. 6 respond | corresponds to each of step S1-S4 of FIG.

(1) When the mobile station UE detects and receives the PCI of the cell B of the base station eNB20-2 during communication via the cell A of the base station eNB20-1 (here, it is assumed as # 10), the cell Among the measurement information periodically sent to the base station eNB20-1 having A, information on the detected PCI (PCI # 10) is sent (steps K1, K2, and S1).

(2) The base station eNB20-1 having the cell A confirms whether or not the PCI # 10 sent from the mobile station UE is in the NCR list, and if there is no particular processing, the processing here Is finished (step K3).

(3) When the PCI # 10 is not in the NCR list in the above-described confirmation in step K3, the base station eNB20-1 having the cell A acquires the PCI # 10 CGI information from the mobile station UE. A request is issued (step S2).

(4) The mobile station UE that has received the request reads the CGI (for example, CGI = 211100) of the cell B from the broadcast information issued by the base station eNB 20-2 having the cell B, and reads the read CGI of the cell B (211100). Report to the base station eNB20-1 having the cell A (steps S3 and S4).

(5) The base station eNB20-1 having the cell A adds the received PCI # 10 and CGI (211100) as a new record to the NCR list. The description of the process of acquiring HO information using this CGI = 211100 is omitted (step K4).

  FIG. 7 is a flowchart for explaining the processing operation in which the wireless communication network system according to the embodiment of the present invention reselects a cell identifier, which will be described next.

(1) When there is a change in the radio wave environment, such as construction of a new base station, change of radio parameters of an existing cell, or change of features around the existing cell, the operator newly creates a PCI collision or PCI confusion. To prevent this from happening, the system starts the process of reselecting cell identifiers and becomes the center of the radio wave environment change (cells for new base stations, cells that change radio parameters, cells that are greatly affected by feature changes) The PCI corresponding to the cell in the base station eNB having is changed to a temporary PCI. The PCI used as this temporary PCI is preferably a PCI that itself does not cause PCI collision or PCI confusion. For example, there is a method in which a PCI reserved for the processing here is a temporary PCI, and a method for selecting a temporary PCI will be described later (step S60).

(2) After that, when a sufficient time (for example, one week) elapses, the NCR list corresponding to each cell is updated by the automatic adjacency setting processing unit ANR203 included in the base station eNB, and the change in the radio wave environment around the cell It will be reflected. Therefore, the base station controller EMS is caused to execute PCI extraction processing to be avoided, which will be described in detail later with reference to FIG. 10 (steps S61 and S62).

(3) A new PCI other than the extracted PCI to be avoided is selected as a PCI having no collision or PCI confusion based on the extraction result of the PCI to be avoided, and then the selected PCI is selected as the new base station. The PCI resetting process is performed for the cell, the cell whose radio parameter is changed, and the cell that is greatly affected by the feature change, and the process ends here. Details of the PCI resetting process will be described later with reference to FIG. 11 (steps S63 and S64).

  The difference between the case of reselecting the PCI of a newly installed base station cell and the case of reselecting the PCI of an existing base station cell is that the latter has already started operation with some PCI set. It is possible that the cell information has already been taken into the NCR list of the neighboring cells. Therefore, information on the own cell may be added to the NCR list due to a change in the radio wave environment, or it may be deleted. In other words, it is necessary to carry out the PCI resetting process of FIG. 11 described later when setting the temporary PCI.

  FIG. 8 is a diagram for explaining an example (part 1) of updating the NCR list of the cell of the base station by the automatic adjacency setting processing ANR. The example described here is an example of how the NCR list is updated by the automatic adjacency setting processing unit ANR203 after the cell A of the base station eNB20-1 starts radio wave emission with the temporary PCI # 2.

  In the example illustrated in FIG. 8, information on the cell B of the base station eNB20-2 (PCI = # 10, PCI) by a report from the mobile stations UE30-1 and UE30-2 connected to the cell A of the base station eNB20-1. CGI = 211100), cell C information (PCI = # 33, CGI = 278626) of the base station eNB20-3 is added to the NCR list of the cell A of the base station eNB20-1. Here, if the cell A of the base station eNB20-1 has the same PCI as the cell B of the base station eNB20-2 or the cell C of the base station eNB20-3, a PCI collision has occurred. I understand. Therefore, when the PCI is reconfigured in the cell A of the base station eNB20-1, the PCIs of the cells (here, the cell B and the cell C) added to the cell A NCR list are included in the own cell NCR list. It can be seen that the PCI must be avoided from being used for reconfiguration because it is a PCI.

  FIG. 9 is a diagram for explaining an example (part 2) of updating the NCR list of the cell of the base station by the automatic adjacency setting processing ANR.

  In the example illustrated in FIG. 9, the report from the mobile station UE30-3 connected to the cell D of the base station eNB20-4, not the cell A of the base station eNB20-1, causes the cell A of the base station eNB20-1 to Information (PCI = # 2, CGI = 212020) is added to the NCR list of the cell D of the base station eNB20-4. Similarly, the information of the cell E of the base station eNB20-5 is reported by the report from the mobile station UE30-4. (PCI = # 33, CGI = 225475) is added to the NCR list of the cell D of the base station eNB20-4. Here, if the cell A of the base station 20-1 has the same PCI as the cell D of the base station 20-4, it can be seen that a PCI collision has occurred. Further, if the cell A of the base station 20-1 has the same PCI as the cell E of the base station 20-5, the PCI confusion occurred in the NCR list of the cell D of the base station 20-4. I understand. Therefore, when the PCI is reconfigured in the cell A, the cell (here, the cell) to which the NCR list (here, the NCR list of the cell D) to which the cell A (CGI) of the base station 20-1 is added belongs. The PCI of D) and the PCI of the cell added to this NCR list (here, cell E) are the PCI of the cell having the NCR list including the CGI of the own cell which is the cell of the base station 20-1. Moreover, since it is PCI contained in the NCR list | wrist including CGI of the own cell which is a cell of the base station 20-1, it turns out that it must avoid using that PCI for reset.

  FIG. 10 is a flowchart for explaining the operation of PCI extraction processing to be avoided in the base station control apparatus EMS, which will be described next. The processing here has (a) a PCI included in the NCR list of the own cell and (b) an NCR list including the CGI of the own cell for the cell of the base station eNB whose base station control device EMS resets the PCI. This is a process of extracting a PCI that satisfies any of the three conditions of the PCI of the cell and (c) the PCI included in the NCR list including the CGI of the own cell from the cell DB 102 and the NCRDB 103 as a PCI to be avoided.

(1) When the extraction process of the PCI to be avoided is started in order for the base station control device EMS to reselect the PCI of a certain cell (the cell whose PCI is to be changed), the NCR of the cell whose PCI is to be changed from the NCRDB 103 The NCR list including the CGI of the cell whose PCI is to be changed is also acquired from the NCRDB 103 (steps S70 and S71).
(2) Next, the PCI of the cell to which the above-mentioned NCR list belongs is acquired from the cell DB 102, and the PCIs included in the above-described two types of NCR lists are acquired from the NCRDB 103, and the process here is terminated (step) S72, S73).

  A new PCI is selected from the remaining PCIs excluding the PCI extracted by the above-described process from the 504 types of PCIs, and a process of setting the selected PCI to a cell for changing the PCI of the eNB is performed. The method of selecting a new PCI from the remaining PCIs excluding the PCI extracted in the above-described processing from 504 types of PCIs is, for example, that another new cell scheduled to be set in the future is a cell that changes the PCI. If it is estimated that there is a possible PCI collision or confusion, the new cell is presumed to be selectable at this stage and is not selected as much as possible for the cell that changes the PCI. A method of selecting a PCI other than the above is conceivable. This can reduce the possibility that there is no PCI that can be selected when selecting a PCI in the future.

  As a method for estimating the possibility of PCI collision or confusion, for example, a method using a radio wave propagation simulator is conceivable. As a simple method, the distance between eNBs that contain cells is used, and If the distance is within 15 km, there is a possibility of PCI confusion, and if it is within 5 km, there is a possibility of PCI collision. Here, the possibility of PCI collision and confusion due to an estimation error is reduced by taking a large distance of 15 km and 5 km, but selectable PCI is reduced.

  Even when there is no remaining PCI obtained by removing the PCI extracted by the above-described processing from 504 types of PCI, it is necessary to select a new PCI. In this case, as a method of selecting a new PCI, for example, there is a method of assigning priorities to the PCI as follows and selecting a PCI having a high priority. That is, the PCI that causes the PCI collision (the PCI in the above-described conditions (a) and (b)) has the lowest priority, the PCI that does not cause the PCI collision and causes the PCI confusion (the above-described conditions (a), ( This is a method of increasing the priority of PCI) that satisfies the condition (c) except for b). In order to further prioritize among them, there may be a plurality of NCR lists including the CGI of the own cell in the above-mentioned condition (c), and the same PCI may be included in some of the NCR lists. Since the influence range of the PCI confusion is larger as the number of included times is larger, a method of lowering the priority as the number of times is larger can be adopted.

  FIG. 11 is a flowchart for explaining the processing operation for resetting the base station control device EMS and the PCI in the base station, which will be described next.

(1) Upon receiving the PCI selection result, the base station control unit 100 in the base station control device EMS10 sets the selected PCI in the NCRDB 103 as a new PCI of the cell whose PCI is to be changed (step S80).

(2) Then, the base station control unit 100 replaces the PCI of the cell included in the NCR list including the CGI of the cell whose PCI is to be changed in the NCRDB 103 with the new PCI, and replaces the NCR list with the cell whose PCI is to be changed. Is reflected in the NCR list of the base station eNB (steps S81 and S82).

  As described above, the provisional PCI is not limited to a method of using a reserved PCI other than the provisional PCI as the provisional PCI, but also from a simulator or geometric method that cannot completely reflect the actual radio wave condition. A method for determining the PCI is conceivable. However, the provisional PCI selected by any such estimation method is not guaranteed not to cause PCI collision or PCI confusion.

  When the temporary PCI generates a PCI collision, the occurrence of the collision cannot be known. Depending on the above-described conditions (a), (b), and (c), the same PCI as the temporary PCI is to be avoided. Since it is not listed, it is necessary not to select the same PCI as the temporary PCI as a new PCI regardless of whether or not the temporary PCI has a PCI collision. In order to prevent the same PCI as the temporary PCI from being listed as a selectable PCI, the conditions (a), (b), and (c) described above are (d) the current PCI (provisional) of the own cell. It can be avoided by adding a condition that PCI is extracted as a PCI to be avoided.

  Also, when the temporary PCI causes PCI confusion, among the NCR lists including the CGI of the own cell described in the above conditions (b) and (c), the NCR list where the PCI confusion occurs can be acquired. Therefore, the PCI of a cell having this NCR list and the PCI included in this NCR list cannot be extracted. This will be described later with reference to FIG.

  FIG. 12 is a diagram for explaining the above-described NCR list that cannot be acquired when temporary PCI causes PCI confusion.

  As shown in FIG. 12, in the state where the mobile station UE30-3 in the service area of the cell D of the base station eNB20-4 is communicating via the base station eNB20-4, a new establishment or a change of PCI is attempted. It is assumed that a radio wave is emitted by setting # 2 as the temporary PCI to the cell A of the base station eNB20-1 having the existing cell A, or a radio wave is emitted by setting # 22 as the temporary PCI. In the NCR list of the cell D of the base station eNB20-4, contents as shown in FIG. 12 as the NCR list T01-4 (excluding data of PCI = # 44) are held. In addition, it is assumed that the mobile station UE30-3 is in a place where the service areas of the cell A and the cell D that can receive the radio wave from the base station eNB20-1 overlap.

  In the above case, the base station eNB20-4 holds the data of PCI = # 2 and PCI = # 22 in the NCR list T01-4, so that the temporary data is not transferred to the cell A of the base station eNB20-1 having the cell A. When # 2 or # 22 is set as the PCI, it can be seen that PCI confusion occurs. When the base station eNB 20-4 reports that the PCI data can be received from the mobile station UE 30-3 by the method of FIG. 5 and FIG. 6 described above, Since it is already included in the NCR list T01-4, the PCI data and the CGI of the cell A are not taken into the NCR list T01-4. Since the NCR list T01-4 does not include the CGI of the cell A, the NCR list T01-4 does not correspond to the NCR list including the CGI of the own cell in the conditions (b) and (c) described above. Therefore, the PCI of the cell to which the NCR list T01-4 belongs and the PCI included in the NCR list T01-4 cannot be extracted as PCIs to be avoided.

  On the other hand, when # 44 is set as the temporary PCI to the cell A of the base station eNB20-1 having the cell A and the radio wave is emitted, the base station eNB20-4 has the data of PCI = # 44 in the NCR list T01-4. Is not held, it can be seen that PCI confusion does not occur. When the base station eNB 20-4 reports that the PCI data can be received from the mobile station UE30-3 by the method shown in FIGS. 5 and 6, the PCI data is stored in the NCR list T01. −4, the data of # 44 as the temporary PCI of the cell A and the CGI of the cell A are taken into the NCR list T01-4 of the cell D. Thus, the NCR list T01-4 includes the CGI of the cell A and corresponds to the NCR list including the CGI of the own cell in the conditions (b) and (c) described above, and thus is acquired in step S71 of FIG. Accordingly, the PCI of the cell to which the NCR list T01-4 belongs and the PCI included in the NCR list T01-4 are extracted as PCIs to be avoided. Here, when a certain NCR list compares the probability of including # 2, the probability of including # 22, and the probability of including both # 2 and # 22, the probability of including both # 2 and # 22 is the smallest. In addition, the probability of including all of # 2, # 22, and # 44 is further reduced. Therefore, it is avoided to perform the procedure of FIG. 7 by using as many temporary PCIs as possible rather than performing the procedure of FIG. 7 with only one temporary PCI (here, # 2 or # 22 or # 44). The number of cases where an NCR list for extracting a PCI to be acquired cannot be acquired can be reduced. Accordingly, it is possible to improve the reliability of selecting a PCI that does not cause PCI collision and confusion according to the embodiment of the present invention.

  FIG. 13 is a flowchart for explaining a PCI resetting process operation when a plurality of temporary PCIs are used. Next, this will be described.

(1) When there is a change in the radio wave environment, such as construction of a new base station, change of radio parameters of an existing cell, or change of features around the existing cell, the operator newly creates a PCI collision or PCI confusion. To prevent this from happening, the system starts the process of reselecting cell identifiers and becomes the center of the radio wave environment change (cells for new base stations, cells that change radio parameters, cells that are greatly affected by feature changes) The PCI corresponding to the cell in the base station eNB having is changed to a temporary PCI. The PCI used as this temporary PCI is preferably a PCI that itself does not cause PCI collision or PCI confusion. For example, as described above, there is a method in which the PCI reserved for the processing here is used as a temporary PCI (step S90).

(2) After that, when a sufficient time (for example, one week) elapses, the NCR list corresponding to each cell is updated by the automatic adjacency setting processing unit ANR203 included in the base station eNB, and the change in the radio wave environment around the cell It will be reflected. Therefore, the base station controller EMS is caused to execute PCI extraction processing to be avoided, which will be described in detail later with reference to FIG. 10 (steps S91 and S92).

  Note that the processing so far is the same as the processing in steps S60 to S62 described in the flow shown in FIG.

(3) After this PCI extraction process to be avoided, it is determined whether or not the PCI extraction process to be avoided has been executed a prescribed number of times (for example, three times). The next temporary PCI is selected from other than the PCI to be avoided. When a plurality of temporary PCIs are used, it is desirable to select the second and subsequent temporary PCIs from those other than the already extracted PCIs to be avoided. This is because there is a high possibility that the PCI to be avoided cannot partially acquire the NCR list (step S93).

(4) After selecting the next temporary PCI in the process of step S93, the temporary PCI is set again, and the process returns to the process from step S91, and the NCR list of the base station eNB in the system is sufficiently updated by the ANR 203 The process returns to the process of waiting until it is performed, and the process is repeated (step 94).

(5) If the PCI extraction process to be avoided has been executed a predetermined number of times, a new temporary PCI is selected from other than the PCI to be avoided, the temporary PCI is set again, and the process ends here ( Steps S95 and S96).

  In order to correctly know the possibility of PCI collision or confusion from the actual radio wave environment, under the actual base station installation status and radio parameter settings, the system is put into operation and radio waves are emitted. There is a need for a function or method for confirming the possibility of occurrence of a PCI collision or confusion by confirming whether or not a collision or confusion has occurred, or by analyzing the reach and influence range of radio waves by some method.

  Next, a case where PCI collision or confusion occurs between neighboring cells in the neighboring cells of the own cell will be described.

  When PCI collision and confusion occur between neighboring cells, the data of all the neighboring cells that are colliding or confusing may not be taken into the NCR list, but depending on the condition (a), those neighboring cells PCI common to the two is extracted. This means that the PCI to be avoided can be correctly extracted. In addition, if the PCI of the own cell does not cause a collision or confusion, the CGI of the own cell is captured by the method of FIGS. 5 and 6 described above, so that depending on the conditions (b) and (c), An NCR list can be obtained. This does not interfere with the operation of the PCI extraction process to be avoided in this embodiment and the object of the present invention. Even if there is no PCI collision or confusion between neighboring cells, there is a case where PCI confusion occurs between neighboring cells in the NCR list of the new own cell, but even in that case, depending on the condition (a) PCIs common to those neighboring cells are extracted. Similarly, this does not interfere with the operation of PCI extraction processing to be avoided in the present embodiment and the object of the present invention.

  Since the present invention is not intended to detect PCI collision or confusion, it cannot detect PCI collision or confusion between neighboring cells. On the other hand, in order to solve the PCI collision and confusion between neighboring cells, the embodiment of the present invention can be solved also in the neighboring cells. However, the cell selection method to be carried out is outside the scope of the present invention.

  According to the above-described embodiment of the present invention, the former method of PCI collision or confusion is not implemented, and the latter method of PCI collision is not implemented. Without estimating the confusion by desktop simulation, etc., it is possible to detect the collision of PCI in accordance with the radio wave environment in the actual operation setting after actually starting the emission of radio waves or changing various wireless parameters and starting the operation. It is possible to select a PCI that does not cause confusion or a PCI that does not easily cause a PCI collision or confusion, and set the selected PCI in a cell.

10 Base station controller (EMS)
20-1 to 20-4 Radio base station (eNB)
30-1 to 30-5 mobile station (UE)
100 Base station control unit 101 Base station data management control unit 102 Cell DB
103 NCRDB
201, 301 Wireless device 202, 302 Communication processing unit 203 Automatic adjacency setting processing unit 204 Handover processing unit 303 Measurement processing unit T01-1 to T01-3 NCR list

Claims (10)

In a cellular radio communication network system comprising a plurality of radio base stations and a base station controller connected to the plurality of radio base stations and controlling the plurality of radio base stations,
The radio base station accommodates one or a plurality of cells which are radio communication areas, and an NCR list in which one physical cell identifier and one cell global identifier are associated with each other. Automatic neighbor relationship setting processing means for performing processing of setting an NCR list related to adjacent cells,
The base station controller manages and controls a cell DB that centrally manages configuration information of a plurality of cells, an NCRDB that centrally manages an NCR list related to neighboring cells, and the cell DB and the NCRDB. wherein and a physical cell identifier and base station data management control means for setting the NCR list,
Base station data management control means of the base station control device,
According to the radio wave environment around a certain cell, it has a function of creating an NCR list indicating the relationship between neighboring cells of the cell, and when the function of creating the NCR list selects the physical cell identifier of the certain cell, The physical cell identifier of the cell included in the NCR list indicating the adjacent cell relationship of the selection target cell of the radio base station that has already started emission of radio waves in the NCR list indicating the adjacent cell relationship of the created cell is physically set. The physical cell identifier of the certain cell is selected from the cell identifier selection candidates , and at that time, the physical cell identifier is excluded from the physical cell identifier selection candidates. by the number of times that, by applying a selection priority to a physical cell identifier, cellular radio and selects a physical cell identifier of the certain cell according to the selection priority Shin network system. In a cellular radio communication network system comprising a plurality of radio base stations and a base station controller connected to the plurality of radio base stations and controlling the plurality of radio base stations,
The radio base station accommodates one or a plurality of cells which are radio communication areas, and an NCR list in which one physical cell identifier and one cell global identifier are associated with each other. Automatic neighbor relationship setting processing means for performing processing of setting an NCR list related to adjacent cells,
The base station controller manages and controls a cell DB that centrally manages configuration information of a plurality of cells, an NCRDB that centrally manages an NCR list related to neighboring cells, and the cell DB and the NCRDB. wherein and a physical cell identifier and base station data management control means for setting the NCR list,
Base station data management control means of the base station control device,
According to the radio wave environment around a certain cell, it has a function of creating an NCR list indicating the relationship between neighboring cells of the cell, and when the function of creating the NCR list selects the physical cell identifier of the certain cell, The physical cell identifier of the cell included in the NCR list indicating the adjacent cell relationship of the selection target cell of the radio base station that has already started emission of radio waves in the NCR list indicating the adjacent cell relationship of the created cell is physically set. A physical cell identifier of the certain cell is selected from the selection candidates of the cell identifier, and at that time, a temporary physical cell identifier is set for the certain cell to be newly installed or PCI is changed, and the certain cell is selected. After a radio wave is emitted from a wireless base station, the NCR list indicating the neighbor cell relationship is updated, and the temporary physical cell identifier is a candidate for selecting a physical cell identifier. Cellular radio communication network system, wherein the removing. The physical cell identifier of the cell included in the NCR list indicating the adjacent cell relationship including the data of the selection target cell in the NCR list in the NCR list indicating the adjacent cell relationship is excluded from physical cell identifier selection candidates. The cellular radio communication network system according to claim 1 or 2 . 3. The cellular radio communication network according to claim 1, wherein a physical cell identifier of a cell to which an NCR list indicating adjacent cell relations including the data of the selection target cell in an NCR list belongs is excluded from physical cell identifier selection candidates. system. Base station data management control means of the base station control device,
An NCR list indicating neighboring cell relations including the configuration target cell in the NCR list is acquired, and the physical cell identifier of the configuration target cell included in the acquired NCR list is changed to the selected new physical cell identifier, and the adjacent cell 3. The cellular radio communication network system according to claim 1, wherein the change is reflected in an NCR list indicating the neighboring cell relationship of the radio base station operating the NCR list indicating the relationship. 4. The cellular wireless communication network system according to claim 2 , wherein a dedicated physical cell identifier not used for other purposes is used as the temporary physical cell identifier. The cellular radio communication network system according to claim 2, wherein a physical cell identifier that is unlikely to cause physical cell identifier collision or confusion is used as the temporary physical cell identifier. The cellular wireless communication network system according to claim 2, wherein a plurality of temporary physical cell identifiers are used as the temporary physical cell identifier. After updating the NCR list indicating the neighboring cell relationship, re-setting the temporary physical cell identifier in the selection target cell and re-updating the NCR list indicating the neighboring cell relationship is repeated a plurality of times. The cellular wireless communication network system according to claim 2, wherein: In a method of selecting a physical cell identifier in a cellular radio communication network system configured to include a plurality of radio base stations and a base station controller connected to the plurality of radio base stations and controlling the plurality of radio base stations,
The radio base station accommodates one or a plurality of cells which are radio communication areas, and an NCR list in which one physical cell identifier and one cell global identifier are associated with each other. Automatic neighbor relationship setting processing means for performing processing of setting an NCR list related to adjacent cells,
The base station controller manages and controls a cell DB that centrally manages configuration information of a plurality of cells, an NCRDB that centrally manages an NCR list related to neighboring cells, and the cell DB and the NCRDB. And a base station data management control means for setting the physical cell identifier and the NCR list,
Base station data management control means of the base station control device,
According to the radio wave environment around a certain cell, it has a function of creating an NCR list indicating the relationship between neighboring cells of the cell, and when the function of creating the NCR list selects the physical cell identifier of the certain cell, The physical cell identifier of the cell included in the NCR list indicating the adjacent cell relationship of the selection target cell of the radio base station that has already started emission of radio waves in the NCR list indicating the adjacent cell relationship of the created cell is physically set. The physical cell identifier of the certain cell is selected from the cell identifier selection candidates , and at that time, the physical cell identifier is excluded from the physical cell identifier selection candidates. by the number of times that, by applying a selection priority to a physical cell identifier, physical cell identification, characterized by selecting a physical cell identifier of the certain cell according to the selection priority Selection method of the child.

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