JP2010028665A - Wireless communication device of mobile communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce power consumption by lightening the load of peripheral base station management processing on a mobile station, and to reduce the overhead of an up control channel. <P>SOLUTION: Report information showing results of cell search of the mobile station MS is sent from the mobile station MS to a base station BSA being synchronized, and the base station BSA determines whether peripheral base stations included in the sent report information on the search results includes an improper peripheral base station as a hand-off destination by reference to a peripheral base station list. When it is determined that an improper peripheral base station is included, an offset list into which a changed offset value for the peripheral base station determined to be improper is entered is transmitted from the base station BSA to the mobile station MS2, and the mobile station MS changes an offset value for the corresponding peripheral base station in a base station management list according to the offset value of the peripheral base station entered into the sent offset list. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a radio communication apparatus used as a base station and a mobile station in a system in which a mobile station performs a neighboring base station search in a mobile communication system employing a cellular system.

  In a cellular mobile communication system, a so-called handoff is performed in which a connection destination base station is switched as the mobile station moves. In a mobile communication system adopting a currently used CDMA (Code Division Multiple Access) communication system, the following processing is performed in preparation for the handoff.

  That is, each base station maintains a list of neighboring base stations describing identification information of base stations that may be handed off next among base stations arranged around its own station, and transmits the information to the mobile station . When the mobile station turns on the power, the pilot signal transmitted from all the neighboring base stations is sequentially received by, for example, the sliding correlation method or the matched filter (matched filter) method, and the reception quality is measured. And establish synchronization with the base station with the best reception quality. Then, the peripheral base station list is received from the base station that has established the synchronization, and thereafter the base station search is performed on the peripheral base stations described in the received peripheral base station list periodically or in accordance with an instruction from the base station. The base station management list is created and managed based on the search result. In the base station management list, for example, a reception station and a base station type representing a priority as a connection destination candidate are described in association with the base station ID.

The mobile station determines whether handoff is necessary based on the base station management list during standby and during communication. Whether or not the handoff is necessary is determined by comparing the communication quality with the currently established base station and the communication quality with the neighboring base stations described in the base station management list. . As a result of this determination, when a neighboring base station with better communication quality than the base station with which synchronization is currently established is found, a handoff request is transmitted to the base station. When a base station receives a handoff request from the mobile station, the base station determines whether or not to permit handoff based on the neighboring base station list, and if so, handoff processing is performed.
However, in such a conventional mobile communication system, the base station transmits a peripheral base station list to each mobile station in order to search for peripheral base stations of the mobile station. For this reason, the overhead of the downlink control channel from the base station to the mobile station becomes extremely large.

On the other hand, recently, a mobile communication system adopting an OFDM (Orthogonal Frequency Division Multiplexing) communication system has been studied (for example, see Non-Patent Document 1). In a system employing the OFDM communication system, time synchronization restrictions are smaller than in an existing mobile communication system employing a CDMA communication system, so that a mobile station can easily perform a neighboring base station search in a relatively short time. For this reason, it is not necessary to transmit the neighboring base station list from the base station in which synchronization is established, and this is expected to reduce the overhead of the downlink control channel from the base station to the mobile station.
3GPP, TR25.814 (V7.1.0), “Physical Layer Aspects for Evolved UTRA”

  By the way, in a mobile communication system adopting the OFDM communication system, for example, a mobile station periodically performs a full cell search with respect to neighboring base stations in preparation for handoff, and the measurement result of the full cell search is sent to a synchronization establishment destination base station. The processing to be reported is expected. However, the peripheral base station management process including the cell search process and the search result report process is performed regardless of the peripheral base station list held by the base station. For this reason, depending on the position of the mobile station and the surrounding wireless environment, the search process and the report process of the search result are unconditionally performed even for a neighboring base station that is inappropriate as a connection destination candidate. Therefore, the processing load on the cell search process of the mobile station is large and the power consumption increases, and the amount of report information of the search result increases, so that the overhead of the uplink control channel from the mobile station to the base station may increase.

  The present invention has been made paying attention to the above circumstances, and the object of the present invention is a system in which the base station list is not transmitted from the base station to the mobile station, and the load on the base station management processing in the mobile station It is an object of the present invention to provide a radio communication apparatus that reduces power consumption by reducing the power consumption and reduces overhead of an uplink control channel.

  In order to achieve the above object, one aspect of the present invention is to provide a plurality of base stations each forming a cell, and a search that represents a selection priority of a base station that is a connection destination candidate by performing a search for the plurality of base stations Search information transmitted from the mobile station in a radio communication apparatus used as the base station in a mobile communication system comprising a mobile station that creates information and performs handoff with reference to the created search information. The base station that is a connection destination candidate included in the received search information is determined whether it is appropriate or inappropriate as a connection destination. If the base station that is determined to be inappropriate as the connection destination is included in the connection destination candidate base stations, the base station that is determined to be inappropriate as the connection destination. Instruction information for lowering the selection priority is configured to be transmitted to the mobile station that transmitted the search information.

  Therefore, according to one aspect of the present invention, the base station determines whether or not information on a peripheral base station that is inappropriate as a connection destination candidate is included in the search information of the peripheral base station transmitted from the mobile station. If it is determined and an inappropriate peripheral base station is included, an instruction to lower the selection priority of the peripheral base station is notified to the mobile station. For this reason, the mobile station can perform a process of reducing the selection priority of the corresponding neighboring base stations included in its own base station management list according to the above instruction. Therefore, the mobile station can exclude the neighboring base station whose selection priority has been changed to be low in the next cell search from the search target, thereby reducing the processing load of the cell search and the time required for the cell search. Can be shortened and power consumption can be reduced. At the same time, it is also possible to reduce the amount of search information transmitted from the mobile station to the base station, thereby reducing the overhead of the uplink control channel from the mobile station to the base station.

  That is, according to one aspect of the present invention, in a system in which a neighboring base station list is not transmitted from a base station to a mobile station, the load on the neighboring base station management process in the mobile station is reduced to reduce power consumption. At the same time, it is possible to provide a wireless communication apparatus that reduces the overhead of the uplink control channel.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a functional configuration of a radio communication apparatus used as a base station in a mobile communication system according to an embodiment of the present invention. This wireless communication apparatus includes an antenna 11, a wireless unit 12, a signal processing unit 13, a network interface 14, a control unit 15, and a peripheral base station information database 16.

  The wireless unit 12 performs modulation / demodulation processing and frequency conversion processing on control data and information data in order to transmit and receive wireless communication signals to and from a mobile station (not shown) via the antenna 11. The signal processing unit 13 is configured by, for example, a DSP (Digital Signal Processor), and performs baseband signal processing such as code decoding processing for control data and information data and format conversion processing for OFDM communication. The network interface 14 transfers the control data and information data to and from a mobile communication control station (not shown).

  The neighboring base station information database 16 stores a neighboring base station list in which identification information of base stations suitable as handoff connection destinations among base stations arranged around the own station is described. The base station identification information includes a base station ID, an identification value of a spreading code set in advance for the base station, and the like.

  The control unit includes, for example, a CPU (Central Processing Unit). As a control function necessary for carrying out the present invention, a search result reception control unit 151, a connection suitability / non-suitability judgment unit 152, an offset list creation unit 153, An update offset list transmission control unit 154 is provided. All of these control functions are realized by causing the CPU to execute an application program stored in a program memory in the control unit 15.

  The search result reception control unit 151 executes a process for receiving and storing information representing the search results of the neighboring base stations periodically transmitted from the mobile station in which synchronization is established with its own base station. To do.

  When the search result reception control unit 151 receives the search result report information of the neighboring base station transmitted from the mobile station, the connection suitability / unsuitability judgment unit 152 is described in the received search result report information. A process of determining whether or not peripheral base stations that are inappropriate as handoff destinations are included in the peripheral base station by referring to the peripheral base station list stored in the peripheral base station information database 16 is executed.

  Specifically, for each of the neighboring base stations described as connection destination candidates in the received search result report information, it is checked whether or not the neighboring base station is listed in the neighboring base station list. If it is not listed in the station list, it is determined that the neighboring base station is an inappropriate base station as a handoff destination.

  The offset list creating unit 153 uses the connection suitability / unsuitability judging unit 152 to create a peripheral base station that is inappropriate as a handoff destination among the peripheral base stations that are connection destination candidates described in the search result report information sent from the mobile station. When it is determined that a station is included, a process of creating an update offset list in which the ID of the peripheral base station determined to be inappropriate and the offset value for the peripheral base station is described is executed.

  The update offset list transmission control unit 154 executes processing for transmitting the update offset list created by the offset list creation unit 153 to the mobile station that is the transmission source.

  On the other hand, a mobile station according to an embodiment of the present invention is configured as follows. FIG. 2 is a block diagram showing the functional configuration. That is, the mobile station includes an antenna 21, a radio unit 22, a signal processing unit 23, an audio processing unit 24, a control unit 25, and a storage unit 26, and further includes a speaker 27 and a microphone 28 as user interfaces. A call unit, an input device 29, and a display device 30.

  The input device 29 includes a dial keypad and a plurality of function keys including a call key, an end key, a cursor key, and the like. The display device 30 includes a display using an LCD or an organic EL.

  The wireless unit 22 performs modulation / demodulation processing and frequency conversion processing on control data and information data in order to transmit and receive wireless communication signals to and from the base station via the antenna 21. The signal processing unit 23 is configured by, for example, a DSP (Digital Signal Processor), and performs baseband signal processing such as code decoding processing for control data and information data and format conversion processing for OFDM communication.

  When the information data decoded by the signal processing unit 23 includes audio data, the audio processing unit 24 decodes the audio data into an analog audio signal and outputs the analog audio signal from the speaker 27. The audio processing unit 24 encodes the transmission audio signal input from the microphone 28 into audio data and outputs the audio data to the signal processing unit 23.

  The storage unit 26 stores telephone directory data, outgoing / incoming call history data, content data such as music and video, and a base station management list created by the control unit 25 described later.

  The control unit 25 includes, for example, a CPU (Central Processing Unit). As control functions necessary for carrying out the present invention, a base station search control unit 251, a search result notification control unit 252, an offset value update processing unit 253, It has. Each of these control functions is realized by causing the CPU to execute an application program stored in a program memory in the control unit 25.

  The base station search control unit 251 performs an all-cell search when the power is turned on, and creates and stores a base station management list indicating selection priorities of peripheral base stations that are connection destination candidates based on the search result. The data is stored in the unit 26. In the base station management list, the ID of the neighboring base station detected by the cell search, the reception quality of the neighboring base station, and the offset value indicating the priority as the connection destination candidate are described. In addition, after the base station management list is obtained, the base station search control unit 251 selects a base station having a higher priority based on the base station management list, and assigns the selected upper peripheral base station. On the other hand, a cell search is performed, and a process of updating the base station management list based on the measurement result is executed at a preset cycle.

  Each time the cell search is performed by the base station search control unit 251, the search result notification control unit 252 sends information for reporting the search result of the cell search to the base station that is the synchronization establishment destination via the uplink control channel. Execute the process to send to.

  The offset value update processing unit 253 monitors the arrival of the update offset list transmitted from the synchronization establishment destination base station after the search result notification control unit 252 transmits the search result information. Then, when the update offset list addressed to the own station is received, the corresponding peripheral in the base station management list stored in the storage unit 26 according to the offset value of the peripheral base station described in the update offset list A process of changing the offset value for the base station is executed.

Next, operations of the base station and mobile station configured as described above will be described.
For example, as shown in FIG. 4, base stations BSA and BSB and base stations BSC and BSD are arranged on both sides of the bay, and form wireless communication areas (cells) ZA, AB and ZC, ZD, respectively. Assume that the mobile station MS exists in the cell ZA of the base station BSA. When the mobile station MS is turned on in this state, a cell search operation for handoff is executed between the mobile station MS and the base station BSA as follows. FIG. 3 is a flowchart showing the processing procedure and processing contents.

  That is, the control unit 25 of the mobile station MS first performs an all-cell search for base stations existing in the vicinity under the control of the base station search control unit 251 in step S32. This all-cell search uses, for example, a sliding correlator or a matched filter (matched filter) provided in the radio unit 22 or the signal processing unit 23 to sequentially receive and receive pilot signals transmitted from the base stations BSA to BSD, respectively. This is done by measuring quality.

  The base station search control unit 251 selects the base station (here, BSA) with the best reception quality based on the measurement result of the all-cell search, and establishes synchronization with the selected base station BSA. At the same time, the base station search control unit 251 creates a base station management list based on the measurement result of the all-cell search, and stores the created base station management list in the storage unit 26. In the base station management list, the ID of the neighboring base station detected by the all cell search, the reception quality of the neighboring base station, and the offset value indicating the priority as the connection destination candidate are described.

  Next, in step S33, the control unit 25 of the mobile station MS controls the base station BSA that has established the synchronization based on the measurement result obtained by the all-cell search under the control of the search result notification control unit 252. The search result report information representing the neighboring base stations excluding is generated, and this report information is transmitted from the wireless unit 22 to the base station BSA where the synchronization is established.

  For example, if only the base station BSB is detected as a neighboring base station by the above all cell search, search result report information including the ID of the base station BSB and its reception quality is created and transmitted to the base station BSA. The When base stations BSB, BSC, BSD are detected as neighboring base stations, search result report information including the IDs of the detected base stations BSB, BSC, BSD and their reception quality is created and the base station Sent to BSA.

  On the other hand, the control unit 15 of the base station BSA monitors the arrival of the search result report information from the mobile station MS under the control of the search result reception control unit 151 in step S34. In this state, when the search result report information transmitted from the mobile station MS is received by the signal processing unit 13 via the wireless unit 12, the connection appropriate / inappropriate determination unit 152 performs the received search in step S35. Judgment is made by referring to the list of neighboring base stations stored in the neighboring base station information database 16 whether the neighboring base stations described in the result report information include a neighboring base station that is inappropriate as a handoff destination. To do.

  If the result of this determination is that an inappropriate neighboring base station is included in the search result report information, an offset value for the neighboring base station determined to be inappropriate by the offset list creating unit 153 in step S36 is lowered. Create an offset list to update the value. Then, under the control of the update offset list transmission control unit 154, the created offset list is transmitted from the signal processing unit 13 to the reporting source mobile station MS2 via the wireless unit 12. On the other hand, if an inappropriate neighboring base station is not included in the search result report information, the offset list is not transmitted.

  For example, as shown in FIG. 4, when the base stations BSA and BSB and the base stations BSC and BSD are arranged opposite to each other across the bay, there is no obstacle between them, so that the cell ZA of the base station BSA The existing mobile station MS may receive not only pilot signals from the base station BSB adjacent to the cell but also pilot signals from the base stations BSC and BSD. In this case, the mobile station MS creates search result report information including the IDs of the base stations BSB, BSC, BSD and their reception quality based on the cell search result, and transmits the search result report information to the base station BSA.

  On the other hand, the peripheral base station information database 16 of the base station BSA stores a peripheral base station list in which only information on peripheral base stations appropriate as handoff destination peripheral base stations is described. For example, in the case of FIG. 4, the base stations BSC and BSD are not suitable as handoff destinations in consideration of the expected moving direction of the mobile station existing in the cell ZA of the base station BSA. Only the information of the station BSB is described.

  For this reason, if the ID of the base station BSB, BSC, BSD is included in the search result report information sent from the mobile station MS, the control unit 15 of the base station BSA determines whether each of the base stations BSB, BSC, BSD Of these, the base stations BSC and BSD are not listed in the neighboring base station list, so that these base stations BSC and BSD are determined to be inappropriate as handoff destinations. Then, the offset value for the base stations BSC and BSD determined to be inappropriate as the handoff destination is set to a lower value in order to make it difficult to be selected as the handoff destination, and the set offset value list is transferred to the report source. Transmit to station MS2. When only the ID of the base station BSB is described in the search result report information sent from the mobile station MS, the base station BSB is included in the peripheral base station list, so it is determined that it is appropriate as a handoff destination. The offset list is not sent.

  The control unit 25 of the mobile station MS monitors the return of the offset list from the base station BSA after transmitting the search result report information. In this state, when the offset list transmitted from the base station BSA is received by the signal processing unit 23 via the wireless unit 22, the offset update processing unit 253 stores the base station management stored in the storage unit 26 in step S37. Among the neighboring base stations described in the list, the offset values of the base stations BSC and BSD described in the received offset list are changed to values specified by the offset list.

  When the first all-cell search process immediately after the establishment of the initial synchronization is completed, the control unit 25 of the mobile station MS performs a cell search for neighboring base stations at a constant cycle under the control of the base station search control unit 251 in step S37. Execute. However, the second and subsequent cell searches after the establishment of the initial synchronization are performed based on the base station management list, not the all cell search, and moreover, depending on the offset value among the neighboring base stations described in the base station management list. The priority shown is only given to higher neighboring base stations.

  Therefore, in the second and subsequent cell searches after the establishment of the initial synchronization, among the neighboring base stations described in the base station management list, the base stations BSC and BSD whose offset value has been changed to a low value by the offset update process are as follows. It is excluded from the search target and only the base station BSB is the search target. As a result, the processing load on the control unit 25 of the mobile station MS when performing the cell search process is reduced, and the time required for the search is also reduced. The result of the cell search is transmitted to the base station BSA as search result report information.

  On the other hand, when the search result report information transmitted from the mobile station MS is received, the control unit 15 of the base station BSA proceeds from step S39 to step S40, and performs the all-cell search immediately after the process synchronization described above. Similarly to the case, the connection suitability / unsuitability determination unit 152 determines whether or not a neighboring base station that is inappropriate as a handoff destination is included in the neighboring base stations described in the received search result report information. The determination is made with reference to the peripheral base station list stored in the peripheral base station information database 16. In this case, the search result report information transmitted from the mobile station MS includes only the search result of the base station BSB as described above. For this reason, the connection suitability / unsuitability judging unit 152 judges that the search result report information does not include an inappropriate neighboring base station, and does not transmit the offset list.

  If the search result report information transmitted from the mobile station MS newly includes an inappropriate peripheral base station, the control unit 15 of the base station BSA determines that the offset list creation unit 153 in step S41. Creates an offset list for updating the offset value for the neighboring base station determined to be inappropriate to a low value, and reports the generated offset list under the control of the update offset list transmission control unit 154. To the mobile station MS2.

  The control unit 25 of the mobile station MS determines whether or not the handoff is necessary in step S43 while monitoring the return of the offset list from the base station BSA in step S42 after transmitting the search result report information. The necessity of this handoff depends on the reception quality of the pilot signal transmitted from the base station BSA that is currently synchronized, and the reception quality of the pilot signal transmitted from the neighboring base station BSB described in the base station management list. Is made by comparing Then, as a result of this determination, if it is determined that the reception quality of the neighboring base station BSB is better than the base station BSA for which synchronization is currently established, a handoff request is transmitted to the base station BSA in step S44.

  When the control unit 15 of the base station BSA detects that a handoff request has arrived from the mobile station MS in step S45, the control unit 15 determines whether to permit handoff based on the peripheral base station list stored in the peripheral base station information database 16 or not. If it is determined and permitted, the handoff process is executed in step S46.

  Thereafter, similarly, in the control unit 25 of the mobile station MS, a cell search process is periodically executed in step S38 and the result is reported to the base station BSA. Is necessary, the process of transmitting a handoff request is repeatedly executed. On the other hand, the control unit 15 of the base station BSA determines whether or not the neighboring base station included in the search result report information sent from the mobile station MS is appropriate or inappropriate as a handoff destination in steps S39 to S41. If a peripheral base station is included, the mobile station MS2 notifies the mobile station MS2 of an offset list for lowering the offset value of the peripheral base station, and the handoff request arrives by monitoring the arrival of the handoff request in steps S45 and S46. In this case, the handoff process is repeatedly executed.

  As described above, in this embodiment, report information indicating the cell search result of the mobile station MS is sent from the mobile station MS to the base station BSA in which synchronization is established, and the search result report information sent by the base station BSA is sent. It is determined with reference to a list of neighboring base stations stored in the neighboring base station information database 16 whether or not neighboring base stations included in are included as inappropriate handoff destinations. If it is determined that an inappropriate peripheral base station BSC or BSD is included as a result of this determination, the ID of the peripheral base station BSC or BSD determined to be inappropriate and the change to the peripheral base station The offset list in which the offset value is described is transmitted from the base station BSA to the mobile station MS2, and the mobile station MS stores the offset list in the storage unit 26 according to the offset values of the neighboring base stations BSC and BSD described in the sent offset list. The offset values for the corresponding neighboring base stations BSC and BSD in the stored base station management list are changed.

  Therefore, the mobile station MS can exclude the neighboring base stations BSC and BSD whose offset values have been changed in the next cell search from the search target, thereby reducing the processing load of the cell search in the control unit 25. Thus, the time required for cell search can be shortened and the power consumption can be reduced. At the same time, it is also possible to reduce the amount of search result report information transmitted from the mobile station MS to the base station BSA, thereby reducing the overhead of the uplink control channel from the mobile station MS to the base station BSA. Is possible.

  Further, in this embodiment, as described above, an offset list in which offset values after change for the neighboring base stations BSC and BSD determined to be inappropriate is created in the base station BSA and sent to the mobile station MS2, and the mobile station MS Then, according to the offset values of the neighboring base stations BSC and BSD described in the sent offset list, the offset values for the corresponding neighboring base stations BSC and BSD in the base station management list are changed. For this reason, the mobile station MS does not have to set the changed offset value by itself, and the change process is simplified accordingly.

  The present invention is not limited to the above embodiment. For example, the base station BSA creates an offset list in which the offset values after change for the neighboring base stations BSC and BSD determined to be inappropriate in the embodiment are sent to the mobile station MS2, and the mobile station MS sends the offset list. The offset value for the corresponding neighboring base station in the base station management list is changed according to the offset value described in. However, the present invention is not limited to this. An instruction command for reducing the offset value is sent from the base station BSA to the mobile station MS, and the mobile station MS that has received this instruction command sets the offset value by a preset amount. You may make it reduce.

  In addition, the types and configurations of base stations and mobile stations, cell search control procedures and processing details, the number of peripheral base stations described in the peripheral base station list, and peripheral base stations whose mobile stations are described in the base station management list The offset value when selecting a neighboring base station as a search target from among the above can be variously modified and implemented without departing from the gist of the present invention.

  In short, the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

It is a block diagram which shows the function structure of the base station of the mobile communication system concerning one Embodiment of this invention. It is a block diagram which shows the function structure of the mobile station of the mobile communication system concerning one Embodiment of this invention. 3 is a flowchart for explaining a cell search processing operation for handoff by the base station and the mobile station shown in FIGS. 1 and 2. It is a figure which shows the example of arrangement | positioning of the cell used for description of the cell search operation | movement shown in FIG.

Explanation of symbols

  BSA to BSD ... base station, ZA to ZD ... cell, MS ... mobile station, 11, 22 ... antenna, 12, 22 ... radio unit, 13, 23 ... signal processing unit, 14 ... network interface, 15, 25 ... control unit , 16 ... Peripheral base station information database, 24 ... Audio processing unit, 26 ... Storage unit, 27 ... Speaker, 28 ... Microphone, 29 ... Input device, 30 ... Display device, 151 ... Search result reception control unit, 152 ... Connection Appropriate / unsuitable determination unit, 153... Offset list creation unit, 154... Update offset list transmission control unit, 251... Base station search control unit, 252.

Claims (6)

Each of the plurality of base stations that form a cell and the plurality of base stations are searched to create search information indicating the selection priority of the base station that is a connection destination candidate, and the created search information is referred to In a mobile communication system comprising a mobile station that performs handoff determination, a wireless communication device used as the base station,
Means for receiving search information transmitted from the mobile station;
A determination unit that determines whether the connection destination candidate is appropriate or inappropriate for the connection destination candidate base station included in the received search information;
If the base station that is a candidate for the connection destination includes a base station that is determined to be inappropriate as a connection destination, the selection priority of the base station that is determined to be inappropriate as the connection destination A wireless communication apparatus used as a base station, comprising: transmission means for transmitting instruction information for reducing the degree to a mobile station that has transmitted the search information. Storage means for storing information on other base stations located in the vicinity as a peripheral base station list;
The determination means determines whether or not a base station that is a connection destination candidate represented by the received search information is included in the peripheral base station list stored in the storage means, and the peripheral base station list The wireless communication apparatus used as a base station according to claim 1, wherein a base station that is not included in the connection destination is determined to be an inappropriate base station as a connection destination. The transmission means includes
The second priority lower than the first priority of the base station of the connection destination candidate notified from the mobile station by the search information, as the selection priority of the base station determined to be inappropriate as the connection destination Means to change to
Means for transmitting identification information of a base station determined to be inappropriate as the connection destination and information indicating the changed second priority to the mobile station that transmitted the search information. A radio communication apparatus used as a base station according to claim 1 or 2. A wireless communication device used as a mobile station that communicates with a wireless communication device used as a base station according to claim 1,
Means for receiving instruction information transmitted from a wireless communication device as the base station;
Means for changing search information to lower the selection priority of a base station determined to be inappropriate as a connection destination in accordance with the received instruction information;
A wireless communication apparatus used as a mobile station, comprising: means for performing handoff determination with reference to the changed search information.   The means for performing the handoff determination includes, from among the plurality of neighboring base stations whose identification information is described in the changed search information, neighboring base stations whose selection priority is changed to a low value according to the instruction information. 5. The wireless communication apparatus used as a mobile station according to claim 4, wherein a search is performed only for neighboring base stations that are excluded and not excluded, and a handoff determination is performed based on the search result. .   6. The means for performing handoff determination further comprises means for transmitting search result report information including only search results for neighboring base stations that have not been excluded to the base station. A wireless communication device used as a mobile station.

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