JP2010212988A - Wireless base station system and handover control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless base station system and handover control method which can eliminate an unnecessary handover without adding any function to a wireless mobile station. <P>SOLUTION: A route specification unit 30 specifies the wireless base station that has issued the handover request information as a first wireless base station, for a wireless mobile station specified by handover request information, and specifies a plurality of routes starting from the first wireless base station as candidate routes and investigates whether the plurality of specified candidate routes include a set of a first route of handover from the first wireless base station to a second wireless base station via one or more other wireless base stations and a second route of handover from the first wireless base station directly to the second wireless base station not via any other wireless base station. If there is a set of the first route and the second route, a skip base station specification unit 32 specifies the one or more other via wireless base stations included in the first route as skip enabled wireless base stations. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a radio base station system and a handover control method.

  When a mobile communication wireless terminal (wireless mobile station) moves away from a wireless base station with which it is connected, the radio wave from the wireless base station weakens, and communication cannot be performed as it is. . For this reason, the radio mobile station performs a handover operation for switching the communication connection destination to another radio base station having a strong radio wave before the radio wave from the radio base station with which the communication is connected weakens or weakens.

  Which radio base station is to be handed over is determined based on the electric field strength. By the way, when the user moves at high speed, the base station that is determined to be optimal during the handover process may no longer be optimal, and must be handed over to another base station again after the handover is completed. I will have to.

  With respect to such a problem, Patent Document 1 describes a system that can reduce the number of handovers. In other words, the wireless mobile station has functions of position detection, azimuth detection, and speed detection, and the wireless mobile station predicts the position of its own station after an arbitrary time and reaches each wireless base station at the predicted position. And the downlink communication quality of each radio base station are calculated. The radio mobile station determines a handover destination radio base station based on these calculated values.

JP 2004-201001 A

  However, in Patent Document 1, it is necessary to add a function for determining a handover destination to a wireless mobile station. In particular, Patent Document 1 requires a sensor for position detection, azimuth detection, and speed detection, which increases the price.

  Therefore, an object of the present invention is to provide a radio base station system and a handover control method that can eliminate unnecessary handover without adding a function to the radio mobile station.

  In order to solve the above-described problems, the present invention provides a radio base station system including a plurality of radio base stations and a control device that controls the plurality of radio base stations. Communication connection is established when the reception level of a signal from a mobile station, a connection information generation unit for generating communication connection information for specifying a communication time for communication connection, and a signal from a wireless mobile station in communication connection is equal to or lower than a predetermined value. Specific wireless mobile station based on handover prohibition information including an instruction to generate a handover request information designating a specific wireless mobile station and to reject a handover request from the specific wireless mobile station received from the control device A handover control unit that rejects a handover request from the mobile station, transmits communication connection information and handover request information to the control device, and prohibits handover from the control device. An information transmission unit for receiving information, and the control device receives communication connection information and handover request information from each radio base station, and transmits information for prohibiting handover to a specific radio base station. A route information creating unit for creating route information representing a route in which each wireless mobile station defines a communication-destination wireless base station in time order based on the communication connection information; With reference to the information, for the radio mobile station specified by the handover request information, a radio base station that has issued the handover request information is a first radio base station, and a plurality of The route is identified as a candidate route, and the first of the plurality of identified candidate routes is handed over from the first radio base station to the second radio base station via one or more other radio base stations A path specifying unit that checks whether there is a set of paths and a second path that is handed over directly from the first radio base station to the second radio base station without passing through another radio base station; A base station specifying unit that specifies one or more other wireless base stations that are included in the first route as skippable radio base stations when there is a set of the second route and the second route A handover management unit that generates handover prohibition information including an instruction to reject a handover request from a radio mobile station to a skippable radio base station.

  Preferably, the route information creating unit further creates route information including the past actual number of times for each route, and the route specifying unit refers to the route information to make the past actual number of times a predetermined number of times or more. As long as specified as the first route.

  Preferably, the route information creating unit further creates route information including the past actual number of times for each route, and the route specifying unit further refers to the route information and the past actual number of times is equal to or greater than a predetermined number. Only the route is specified as the second route.

  Preferably, the route information creating unit further creates route information including information indicating the time of communication connection with the radio base station included in the route for each route, and the route specifying unit further refers to the route information. Thus, the first route is specified only for a route within a predetermined time from the end of communication with the first wireless base station to the start of communication with the second wireless base station.

  Preferably, the route information creating unit further creates route information including information indicating the time of communication connection with the radio base station included in the route for each route, and the route specifying unit further refers to the route information. Thus, the second route is specified only when the time from the end of communication with the first radio base station to the start of communication with the second radio base station is within a predetermined time.

  Preferably, the route information creation unit further creates route information including information indicating a time of communication connection with the radio base station included in the route for each route, and the handover management unit performs communication included in the route information. Based on the connected time, a time for prohibiting handover to the specified skippable radio base station is determined, and handover prohibition information including the determined handover prohibition time is generated, and the handover control unit receives The handover request from the wireless mobile station is rejected for the handover prohibition time specified by the handover prohibition information.

  Preferably, the route specifying unit specifies the first route only when the number of wireless base stations that have passed from the first wireless base station to the second wireless base station is equal to or less than a predetermined number.

  The present invention also relates to a handover control method in a radio base station system comprising a plurality of radio base stations and a control device that controls the plurality of radio base stations, wherein each radio base station communicates with each other and moves wirelessly. A step of transmitting communication connection information for specifying a communication time for communication with the station to the control device, a step of receiving the communication connection information by the control device, and a wireless communication based on the communication connection information. In the past communication, a step of creating route information representing a route in which the communication-destination wireless base stations with which the communication connection has been made is specified in time order, and each wireless base station from a wireless mobile station that is in communication connection A step of transmitting handover request information designating a wireless mobile station in communication connection to the control device when the signal reception level becomes a predetermined value or less; The step of receiving the request information, and the control device refers to the path information, and for the radio mobile station specified by the handover request information, the radio base station that has issued the handover request information is designated as the first radio base station. And specifying a plurality of routes starting from the first radio base station as candidate routes, and from among the specified candidate routes, the first radio base station via one or more other radio base stations A set of a first route handed over to the second radio base station and a second route handed over directly from the first radio base station to the second radio base station without passing through another radio base station A step of checking whether or not there is a step, and when the control device has a set of a first route and a second route, a step of specifying one or more other wireless base stations that have passed through as a wireless base station that can be skipped And the control device A step of transmitting handover prohibition information including an instruction for rejecting a handover request from a radio mobile station to a radio base station capable of skipping, a step of receiving a handover prohibition information by a skippable radio base station, A skippable radio base station rejecting a handover request from a radio mobile station specified by the handover prohibition information.

  According to the present invention, unnecessary handover can be eliminated without adding a function to the radio mobile station.

It is a figure showing the radio | wireless system of embodiment of this invention. It is a figure showing the structure of the radio base station system of embodiment of this invention. It is a figure showing communication connection information. It is a figure showing the example of call log information. It is a figure for demonstrating an example of a telephone call history. It is a figure for demonstrating another example of a telephone call history. It is a figure showing the example of route information. It is a flowchart showing the operation | movement procedure which produces the log | history of the path | route in the radio base station system of embodiment of this invention. It is a flowchart showing the control procedure of the handover of the radio base station system of the embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings.
(Constitution)
FIG. 1 is a diagram showing a wireless system according to an embodiment of the present invention.

  With reference to FIG. 1, this wireless communication system includes a plurality of wireless mobile stations # 1 and # 2 and a wireless base station system 12. The radio base station system 12 includes a plurality of radio base stations A to Z and a control device 10 that controls the plurality of radio base stations A to Z.

FIG. 2 is a diagram showing the configuration of the radio base station system according to the embodiment of the present invention.
In FIG. 2, the radio base stations A to Z are represented by one radio base station A as a representative. The wireless base station A and the control device 10 are connected by a wired communication line 40 such as an optical fiber.

  The radio base station A includes an antenna 2, a radio communication unit 4, a handover control unit 6, a connection information generation unit 28, and an information transmission unit 8.

The wireless communication unit 4 performs wireless communication with a wireless mobile station via the antenna 2.
The connection information generation unit 28 creates communication connection information when communication with a wireless mobile station is started.

FIG. 3 is a diagram showing communication connection information.
As shown in FIG. 3A, the communication connection information includes a radio base station ID, a radio mobile station ID, and a communication date and time. The ID of the own station is described in the radio base station ID. In the wireless mobile station ID, the ID of the wireless mobile station of the communication partner is described. The communication date and time describes the date and time when communication was started.

  FIG. 3B shows communication connection information created when the wireless base station A starts communication connection with the wireless mobile station 3 at 8:14:23 on June 13, 2009. FIG. 3C shows communication connection information created when the wireless base station B starts communication connection with the wireless mobile station 3 on June 13, 2009, at 8:16:35. FIG. 3D shows communication connection information created when the wireless base station C starts a communication connection with the wireless mobile station 3 at 8:17:48 on June 13, 2009. FIG. 3E shows communication connection information created when the wireless base station D starts communication connection with the wireless mobile station 3 at 8:20:01 on June 13, 2009.

  Referring to FIG. 2 again, the handover control unit 6 further creates handover request information when the reception strength of the signal from the wireless mobile station with which the communication is connected falls below a predetermined threshold. . The handover request information includes a radio base station ID and a radio mobile station ID. The ID of the own station is described in the radio base station ID. In the wireless mobile station ID, the ID of the wireless mobile station of the communication partner is described.

  Further, when the handover control unit 6 receives handover prohibition information including the ID of a radio mobile station that prohibits handover from the control device 10, the handover control unit 6 starts from an unrelated mobile station specified by the handover prohibition information for a certain period of time. Reject the handover request.

  The information transmission unit 8 transmits communication connection information and handover request information to the control device 10 via the communication line 40. Further, the information transmission unit 8 receives handover prohibition information from the control device 10 via the communication line 40.

  The control device 10 includes an information transmission unit 14, a communication connection information storage unit 16, a call history information creation unit 18, a call history information storage unit 20, a route information creation unit 22, a route information storage unit 24, a route A specifying unit 30, a skip base station specifying unit 32, and a handover management unit 26 are provided.

  The information transmission unit 14 receives communication connection information from the radio base station through the communication line 40 and stores it in the communication connection information storage unit 16. In addition, the information transmission unit 14 receives handover request information from the radio base station through the communication line 40. Further, the information transmission unit 14 transmits handover prohibition information to a specific radio base station through the communication line 40.

(Call history information)
The call history information creating unit 18 creates call history information based on the communication connection information and stores it in the call history information storage unit 20. Here, the call history information represents the radio base stations of communication counterparts with which each radio mobile station has established communication connection in one call, in order of time, and the communication time with each radio base station.

FIG. 4 is a diagram illustrating an example of call history information.
Referring to FIG. 4, for example, the call history information of call ID “000” indicates that the wireless base station of the communication partner is set in the order of M → A → B → C → D → K → J for wireless mobile station 3. Indicates that it has been switched. Further, the call history information of the call ID “000” has a communication time with M (that is, a time from the start of communication with M to switching to A) “1 minute 12 seconds”, and a communication time with A. (That is, the time from the start of communication with A to the switching to B) is “2 minutes 12 seconds”, the communication time with B is “1 minute 13 seconds”, and the communication time with C is “2 minutes” “13 seconds” indicates that the communication time with D is “1 minute 33 seconds” and the communication time with K is “2 minutes 15 seconds”.

  Further, the call history information of the call ID “004” indicates that the wireless base station of the communication partner is switched in the order of J → A → D → S → Q for the wireless mobile station 3. Further, the call history information of the call ID “004” has a communication time with J (that is, a time from the start of communication with J to switching to A) of “2 minutes 34 seconds”, and a communication time with A. (That is, the time from the start of communication with A to the switch to D) is “3 minutes 3 seconds”, the communication time with D is “2 minutes 43 seconds”, and the communication time with S is “3 minutes” 14 seconds ".

FIG. 5 is a diagram for explaining an example of a call history.
FIG. 5 shows an example in which the wireless base station of the communication partner is switched in the order of A → B → C → D when the call ID of FIG. 4 is “000”. In the figure, at the CS-A level 1, CS-B level 1, CS-C level 1, and CS-D level 1, the strength of the received signal from the radio base stations A, B, C, and D is level 1. Represents a place. CS-A level 0 and CS-D level 0 represent locations where the strength of the received signals from radio base stations A and D are level 0. The wireless mobile station searches for a handover destination wireless base station when the strength of the signal from the wireless base station in communication connection becomes level 1 or less, but until the strength of the signal from the wireless base station reaches level 0. Can communicate with the radio base station.

  With reference to FIG. 5, the wireless mobile station 3 is handed over to the wireless base station A at the point P1, time T1, and starts communication. Thereafter, when the wireless mobile station 3 arrives at the point PA, the strength of the received signal from the wireless base station A becomes level 1 or less, and therefore the wireless mobile station 3 searches for the next handover destination wireless base station. The wireless mobile station 3 detects that the intensity of the signal from the wireless base station B is maximum, and performs a handover to the wireless base station B at the point P2 and time T2 to start communication. Thereafter, when the wireless mobile station 3 arrives at the point PB, the strength of the received signal from the wireless base station B becomes level 1 or less, and therefore the wireless mobile station 3 searches for the next handover destination wireless base station. The wireless mobile station 3 detects that the intensity of the signal from the wireless base station C is maximum, and performs a handover to the wireless base station C at the point P3 and time T3 to start communication. After that, when the wireless mobile station 3 arrives at the point PC, the strength of the received signal from the wireless base station C becomes level 1 or less, so the wireless mobile station 3 searches for the next handover destination wireless base station. The wireless mobile station 3 detects that the signal strength from the wireless base station D is maximum, and performs handover to the wireless base station B at the point P4 and time T4 to start communication.

FIG. 6 is a diagram for explaining another example of the call history.
FIG. 6 shows an example in which the wireless base station of the communication partner is switched in the order of A → D when the call ID of FIG. 4 is “004”. Further, the call history in FIG. 6 represents a call history when the user of the wireless mobile station 3 moves along the same route as in FIG. 5 at the same time on another day.

  With reference to FIG. 6, the wireless mobile station 3 is handed over to the wireless base station A at the point P1, time T1, and starts communication. Thereafter, when the wireless mobile station arrives at the point PA, the strength of the received signal from the wireless base station A becomes level 1 or less, and therefore, the wireless mobile station searches for the next handover destination wireless base station. The radio mobile station 3 detects that the signal strength from the radio base stations B and C is high, and requests the radio base stations B and C to perform handover. Is full, the handover request is rejected. Thereafter, the wireless mobile station 3 detects that the intensity of the signal from the wireless base station D is maximum, and performs handover to the wireless base station D at the point P5 and time T5 to start communication.

  Comparing the call history of FIG. 5 with the call history of FIG. 6, the call history of FIG. 5 has a smaller number of handovers even though the wireless mobile station 3 has moved the same route at the same time. Therefore, in order to reduce the number of times of handover, it is effective to refer to the past call history and switch the radio base station to be handed over in the same manner as the call history with a small number of handovers. The reason for using the past call history is that a person's movement route has a certain tendency and often moves along the same route.

  In order to facilitate a route search with a small number of handovers, it is desirable to process and edit the call history information to create the next route information.

(Route information)
Referring again to FIG. 2, the route information creation unit 22 creates route information based on the call history information and stores it in the route information storage unit 24. Here, four pieces of route information are extracted by shifting a plurality of radio base stations arranged in the order of time included in the call history information one by one from the top (two or three at the end), and four ( This represents the actual number of times of each route and the average value of the communication time with the wireless base station included in the route, with 2 or 3 at the end) as one route.

  For example, when there is one or more “M → A → B → C” routes in the call history information, the route information creation unit 22 counts the number of times. The route information creation unit 22 calculates the average value of the communication time with M, the average value of the communication time with A, and the average value of the communication time with B in all “M → A → B → C” routes. . Since the call history information of the call ID “000” includes the route “M → A → B → C”, the actual number of times of the route “M → A → B → C” for the wireless mobile station 3. Is counted up “once”. Further, since the call history information of the call ID “000” includes the route “A → B → C → D”, the route of “A → B → C → D” for the wireless mobile station 3 is included. The number of achievements is counted up “once”. Further, since the call history information of the call ID “004” includes the route “A → D”, the actual number of times of the route “A → D” for the wireless mobile station 3 is counted as “1”. Is up.

FIG. 7 is a diagram illustrating an example of route information.
Referring to FIG. 7, the route information of route ID “000” indicates that the wireless mobile station 3 has the actual number of times of switching the wireless base station in the order of B → C → D next to wireless base station A. Indicates that there are “14 times”. Further, in the route information of route ID “000”, the average value of the communication time with A is “2 minutes 32 seconds”, the average value of the communication time with B is “1 minute 20 seconds”, and C This means that the average value of the communication time is “2 minutes 20 seconds”.

  Further, the route information of the route ID “001” indicates that the wireless mobile station 3 has “5 times” the actual number of times of the route in which the wireless base station is switched to D after the wireless base station A. Then, the route information of the route ID “001” represents that the average value of the communication time with A is “3 minutes 10 seconds”.

  Further, the route information of the route ID “002” indicates that the wireless mobile station 3 has “11 times” the actual number of times of switching the wireless base station in the order of E → G → M next to the wireless base station A. . Further, in the route information of route ID “002”, the average value of the communication time with A is “1 minute 34 seconds”, the average value of the communication time with E is “1 minute 34 seconds”, It means that the average value of the communication time is “2 minutes 02 seconds”.

  Further, the route information of the route ID “003” indicates that the wireless mobile station 3 has “3 times” the actual number of times that the wireless base station A is switched to the next G after the wireless base station A. The route information of the route ID “003” indicates that the average value of the communication time with A is “2 minutes 50 seconds”.

  The path specifying unit 30 refers to the path information, and for the radio mobile station included in the handover request information, the radio base station included in the handover request information is the first radio base station, and the first radio base station A plurality of routes starting from are identified as candidate routes. The path identifying unit 30 includes a first path that is handed over from the first radio base station to the second radio base station via one or more other radio base stations among the plurality of identified candidate paths. Then, it is checked whether there is a second set of paths that are handed over directly from the first radio base station to the second radio base station without passing through another radio base station.

  For example, when the wireless mobile station included in the handover request information is “3” and the wireless base station is “A”, the first wireless base station is “A” according to the path information of FIG. A plurality of routes starting from the first radio base station (A) are candidate routes. Among the candidate routes, the first route (route ID “000”) handed over from A to B via B and C and the second route handed over directly from A to D (route ID “001”) ) Is detected. Among the candidate routes, the first route (route ID “002”) handed over from A to E via E and the second route (route ID “003”) handed over directly from A to G ) Is detected.

  When it is determined that there is a set of the first route and the second route, the skip base station specifying unit 32 specifies the wireless base station that is included in the first route as a wireless base station that can be skipped. . In the above-described example, the wireless base stations that are included in the first route are “B”, “C”, and “E”.

  The handover management unit 26 of the control device 10 transmits handover prohibition information for prohibiting handover to the radio mobile station included in the handover request information to the identified skippable radio base station.

(History recording operation)
FIG. 8 is a flowchart showing an operation procedure for creating a route history in the radio base station system according to the embodiment of the present invention.

  Referring to FIG. 8, when newly starting communication with the radio base station (YES in step S101), handover control unit 6 of radio base stations A to Z performs communication connection information as shown in FIG. Is created (step S102).

  Next, the information transmission unit 8 of the radio base stations A to Z transmits the created communication connection information to the control device 10 through the communication line 40 (step S103).

  Next, the information transmission unit 14 of the control device 10 receives the communication connection information (YES in step S104), and stores the received communication connection information in the communication connection information storage unit 16 (step S105).

  Next, the call history information creating unit 18 of the control device 10 creates call history information as shown in FIG. 4 based on the communication connection information and stores it in the call history information storage unit 20 (step S106).

  Next, the route information creation unit 22 of the control device 10 creates route information as shown in FIG. 7 based on the call history information and stores it in the route information storage unit 24 (step S107).

(Handover control operation)
FIG. 9 is a flowchart showing a handover control procedure of the radio base station system according to the embodiment of the present invention.

  Referring to FIG. 9, the handover control unit 6 of the radio base station A, when the reception intensity of the signal from the radio mobile station connected for communication is below a predetermined threshold (YES in step S201), Handover request information is transmitted to the control apparatus 10 through the communication line 40 (step S202).

  Next, the information transmission unit 14 of the control device 10 receives the handover request information (YES in step S203).

  Next, the route specifying unit 30 of the control device 10 refers to the route information stored in the route information storage unit 24, and for the wireless mobile station included in the handover request information, the wireless included in the handover request information. The base station is a first radio base station, and a plurality of routes starting from the first radio base station are specified as candidate routes. The path identifying unit 30 of the control device 10 performs handover from the first candidate radio base station to the second radio base station via one or more other radio base stations among the plurality of identified candidate paths. It is checked whether there is a set of one route and a second route that is handed over directly from the first radio base station to the second radio base station without passing through another radio base station (step S204).

  If there is a set of the first route and the second route (YES in step S205), the skip base station specifying unit 32 of the control device 10 determines one or more other routes included in the first route. Are determined as skippable radio base stations (step S206).

  Next, the handover management unit 26 of the control device 10 transmits handover prohibition information for prohibiting handover to the radio mobile station included in the handover request information to the identified skippable radio base station. (Step S207).

  Next, the information transmission unit 8 of the radio base station receives the handover prohibition information (YES in step S208).

  Next, the handover control unit 6 of the radio base station rejects a handover request from an unrelated mobile station included in the handover prohibition information for a certain time (step S209).

  As described above, according to the radio base station system of the embodiment of the present invention, the radio base station is switched in the same manner as the radio base station switching method in which the number of handovers was small in the past call. Since the control is performed, unnecessary handover can be eliminated without adding a function to the radio mobile station.

(Modification)
The present invention is not limited to the above embodiment. For example, the following modifications are also included.

(1) Number of times of route The route specifying unit 30 may add a condition that the past number of times is a predetermined number or more as a condition for selecting the first route with reference to the route information. For example, in the example of FIG. 7, if the predetermined number of times is set to 12, only the set of the first route (route ID “000”) and the second route (route ID “001”) is specified. The set of the route (route ID “002”) and the second route (route ID “003”) is not specified.

  Further, the route specifying unit 30 may refer to the route information and add a condition that the past actual number of times is a predetermined number or more as a condition for selecting the second route. For example, in the example of FIG. 7, if the predetermined number of times is set to four, only the set of the first route (route ID “000”) and the second route (route ID “001”) is specified. The set of the route (route ID “002”) and the second route (route ID “003”) is not specified.

  In addition, the route specifying unit 30 refers to the route information, and the past actual number of times is a first predetermined number or more as a condition for selecting as the first route, and for selecting as the second route As a condition, a condition that the past actual number of times is the second predetermined number or more may be added. For example, in the example of FIG. 7, if the first predetermined number of times is set to 12 and the second predetermined number of times is set to 6, the set of the first route and the second route is not specified.

(2) Communication time As a condition for selecting as the first route, the route specifying unit 30 is the time from the end of communication with the first radio base station to the start of communication with the second radio base station, or time You may add the condition that the average (when the frequency | count of results is 2 times or more) is within predetermined time. For example, in the example of FIG. 7, if the predetermined time is set to 6 minutes, only the set of the first route (route ID “002”) and the second route (route ID “003”) is specified. The set of the route (route ID “000”) and the second route (route ID “001”) is not specified.

  In addition, as a condition for selecting as the second route, the route specifying unit 30 is the time from the end of communication with the first radio base station to the start of communication with the second radio base station, or the average of the times ( A condition that the number of achievements is 2 or more) may be added within a predetermined time. For example, in the example of FIG. 7, if the predetermined time is set to 3 minutes, only the set of the first route (route ID “002”) and the second route (route ID “003”) is specified. The set of the route (route ID “000”) and the second route (route ID “001”) is not specified.

  Further, the path specifying unit 30 refers to the path information, and as a condition for selecting as the first path, the time from the end of communication with the first radio base station to the start of communication with the second radio base station t Or the average of the times (when the actual number of times is 2 or more) is within the first predetermined time and the second condition from the end of communication with the first radio base station as a condition for selecting as the second route A condition may be added that the time until the start of communication with the wireless base station or the average time (when the actual number of times is two or more) is within the second predetermined time. For example, in the example of FIG. 7, if the first predetermined time is set to 5 minutes and the second predetermined time is set to 3 minutes, the set of the first route and the second route is not specified.

(3) Number of wireless base stations to be routed In the embodiment of the present invention, the number of other wireless base stations to be routed included in the first route is 2 or less. While shifting a plurality of radio base stations arranged in chronological order included in each one from the top, extract four (two or three at the end) and four (two or three at the end) However, the present invention is not limited to this.

  For example, the number of other wireless base stations that are included in the first route may not be limited, or a predetermined number (not limited to two) or less may be provided. Then, the route information creation unit 22 can create route information according to the limit on the number of other radio base stations. For example, when there are three restrictions, five can be used as one route.

(4) Time for rejecting handover request In the embodiment of the present invention, when receiving the handover prohibition information, the radio base station receives a request from the radio mobile station specified by the handover prohibition information for a certain period of time. Although the handover request is rejected, the present invention is not limited to this.

  For example, the handover management unit 26 of the control device 10 sets the time from the start of communication with the first radio base station to the end of communication with the second radio base station on the first route, or a certain time for this time. The addition or subtraction time may be determined as the handover prohibition time, and handover prohibition information including the handover prohibition time may be generated. Alternatively, the handover management unit 26 adds or subtracts a certain time to the time from the start of communication with the first radio base station to the end of communication with the skippable radio base station on the first route. The time may be determined as a handover prohibition time.

  The handover control unit 6 of the wireless mobile station that has received the handover prohibition information may reject the handover request from the wireless mobile station for the handover prohibition time specified by the handover prohibition information.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  2 antenna, 4 radio communication unit, 6 handover control unit, 8, 14 information transmission unit, 10 control device, 12 radio base station system, 16 communication connection information storage unit, 18 call history information creation unit, 20 call history information storage Unit, 22 route information creation unit, 24 route information storage unit, 26 handover management unit, 28 connection information generation unit, 30 route identification unit, 32 skip base station identification unit, 40 communication line.

Claims (8)

A radio base station system comprising a plurality of radio base stations and a control device that controls the plurality of radio base stations,
Each radio base station
A connection information generating unit that generates communication connection information that identifies a communication-connected wireless mobile station, and a communication time of the communication connection;
When the reception level of a signal from a wireless mobile station in communication connection becomes a predetermined value or less, handover request information specifying the wireless mobile station in communication connection is generated, and the identification received from the control device A handover control unit for rejecting a handover request from the specific radio mobile station based on handover prohibition information including an instruction to reject a handover request from the radio mobile station;
An information transmission unit that transmits the communication connection information and the handover request information to the control device, and receives the handover prohibition information from the control device;
The control device includes:
An information transmission unit that receives the communication connection information and the handover request information from each radio base station, and transmits the handover prohibition information to a specific radio base station;
Based on the communication connection information, each wireless mobile station in the past communication, a route information creation unit for creating route information representing a route in which the wireless base station of the communication partner with which the communication connection was established is defined in time order;
Referring to the path information, for the radio mobile station specified by the handover request information, the radio base station that has issued the handover request information is a first radio base station, and the first radio base station is A plurality of starting routes are identified as candidate routes, and the first wireless base station to the second wireless base station via one or more other wireless base stations among the identified candidate routes. Whether there is a set of a first route that has been handed over and a second route that has been handed over directly from the first radio base station to the second radio base station without passing through another radio base station A route identification part to be examined;
Base station specification that specifies one or more other wireless base stations that are included in the first route as skippable wireless base stations when there is a set of the first route and the second route And
A radio base station system comprising: a handover management unit that generates the handover prohibition information including an instruction to reject a handover request from the radio mobile station to the specified skippable radio base station. The route information creation unit further creates route information including the past number of times for each route,
2. The radio base station system according to claim 1, wherein the route specifying unit specifies the first route with reference to the route information only for a route having a past actual number of times of a predetermined number or more. The route information creation unit further creates route information including the past number of times for each route,
2. The radio base station system according to claim 1, wherein the route specifying unit further specifies the second route by referring to the route information only for a route having a past actual number of times of a predetermined number or more. The route information creation unit further creates route information including information representing the time of communication connection with the wireless base station included in the route for each route,
The route specifying unit further refers to the route information and is limited to a route within a predetermined time from the end of communication with the first radio base station to the start of communication with the second radio base station. The radio base station system according to claim 1, which is specified as the first route. The route information creation unit further creates route information including information representing the time of communication connection with the wireless base station included in the route for each route,
The route specifying unit further refers to the route information and is limited to a route within a predetermined time from the end of communication with the first radio base station to the start of communication with the second radio base station. The radio base station system according to claim 1, which is specified as the second route. The route information creation unit further creates route information including information representing the time of communication connection with the wireless base station included in the route for each route,
The handover management unit determines a time for prohibiting handover to the identified skippable radio base station based on a communication connection time included in the path information, and determines the determined handover prohibition time Generating the handover prohibition information including:
The radio base station system according to any one of claims 1 to 3, wherein the handover control unit rejects a handover request from the radio mobile station for a handover prohibition time specified by the received handover prohibition information. .   The route specifying unit further specifies the first route only when the number of wireless base stations passed from the first wireless base station to the second wireless base station is a predetermined number or less. Item 7. The radio base station system according to any one of Items 1 to 6. A handover control method in a radio base station system comprising a plurality of radio base stations and a control device that controls the plurality of radio base stations,
Each wireless base station transmits to the control device communication connection information for specifying the communication time of the wireless mobile station connected to the communication, and the communication time of the communication connection;
The control device receiving the communication connection information;
The control device creating route information representing a route in which each wireless mobile station defines a wireless base station of a communication partner with which communication connection has been established in time order based on the communication connection information; ,
Each radio base station transmits handover request information designating the radio mobile station currently connected to the control device when the reception level of a signal from the radio mobile station currently connected to the communication becomes a predetermined value or less. And steps to
The control device receiving the handover request information;
The control device refers to the route information, and for the radio mobile station specified by the handover request information, the radio base station that issued the handover request information is the first radio base station, and the first A plurality of routes starting from the wireless base station of the first wireless base station are identified as candidate routes, and the second route from the first wireless base station via one or more other wireless base stations among the plurality of identified candidate routes. A set of a first route handed over to the second radio base station and a second route handed over directly from the first radio base station to the second radio base station without passing through another radio base station. A step to check if there is,
The control device, when there is a set of the first route and the second route, to specify one or more other wireless base stations that have passed through as a wireless base station that can be skipped,
The control device transmitting handover prohibition information including an instruction to cause the skipable radio base station to reject a handover request from the radio mobile station;
The skippable radio base station receiving the handover prohibition information;
A handover control method comprising: the skippable radio base station rejecting a handover request from a radio mobile station specified by the handover prohibition information.

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