JPH07298332A - Mobile communication cell deciding method and its mobile station device - Google Patents

Abstract

PURPOSE:To make a mobile station efficiently select an optimum base station for a communication by deciding a cell in cell code scanning order given priority so as to find a perch channel of higher reception level in a short time. CONSTITUTION:A base station reports the spread codes of its station peripheral cells via a control channel and the data are reported to a 3rd control part 34 through a supervisory control part 25. A code generation part 33 generate the spread codes of those peripheral cells in order, correlator 31 finds collation with a received signal in order, and a reception level detector 32 performs level detection. As a result of the scanning, the perch channel with the highest reception level, i.e., the best base station is selected. When the mobile station moves and reaches the border part between two stations, a two-station simultaneous connection state is entered. The supervisory control part 25, when obtaining two peripheral cell codes checks the common code between the two cell codes, increases the priority of the cell codes, and increases the scanning order and frequency to detect the reception level. Consequently, the perch channel which is high in transition probability and high in reception level can efficiently be found in a short time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication cell determining method and apparatus for efficiently determining a scan order in a cellular mobile communication system adopting code division multiple access.

[0002]

2. Description of the Related Art In recent years, a code division multiple communication system (C) has been known in which information is spread spectrum by spread code and transmitted, and different spread codes are used to form different channels.
DMA; Code Division Multipl
e-Access) mobile communication system is proposed,
Development is in progress for its practical application.

In addition, in the mobile communication system such as the code division multiple communication system, a cell covering a relatively narrow range constitutes a wide service area, and a mobile station and each cell moving in this service area. Communication is performed with a base station provided for each. Therefore, as the mobile station moves, the base station provided for each cell that is optimal for communication changes from moment to moment. Therefore, in a mobile communication system, it is necessary to perform so-called cell determination (cell selection), which appropriately selects a base station optimal for communication.

Whether or not the cell determination is performed accurately has a great influence on the subscriber capacity and communication quality. That is, if a distant cell is erroneously selected, both the mobile station and the base station will transmit at a higher transmission power than that when the correct selection is made. As a result, the interference exerted on the other station becomes large, and the signal-to-interference signal ratio at the other station becomes small, so that the communication quality deteriorates. In addition, the increase in interference reduces the number of stations that can be simultaneously connected, which reduces the subscriber capacity.

Such a cell determination method will be described by taking a conventional general mobile communication method as an example. First, the base station constantly informs the mobile station of incoming call information, control channel structure, standby channel information, and perch channel information of adjacent cells for cell determination on the perch channel.

On the other hand, the mobile station sequentially searches the perch channels stored in advance in the storage device in the mobile station when the power is turned on, and measures the reception level of each perch channel. From the perch channels whose measurement results exceed the preset threshold, select the highest level perch channel to determine the standby base station, start receiving the control channel of that base station, and wait. Transition to the state.

In this standby state, it is considered that the optimum base station for communication changes momentarily with the movement of each cell of the mobile station. Therefore, the perch channel of the adjacent cell notified by the perch channel is changed. It becomes necessary to search sequentially and measure the reception level. That is, the reception level of the perch channel of the adjacent cell is compared with the current reception level of the perch channel plus a predetermined threshold value, and the reception level of the perch channel of the adjacent cell is higher. If so, it is determined that the cell has been transferred, and the standby control channel is changed. When the mobile station makes a call, a connection request signal is transmitted to the cell-selected base station.

Further, during communication, the perch channels of adjacent cells notified from the base station when the communication channel is established are sequentially searched to measure the reception level. Compare the measured reception level of the perch channel of the adjacent cell and the value obtained by adding a predetermined threshold to the reception level of the current communication channel, if the reception level of the perch channel of the adjacent cell is large, It is determined that the cell has been transferred, and channel switching is performed.

Next, the case of the code division multiple communication system will be described. A cell-specific frequency or spreading code is assigned to each cell. The spreading code assigned to each cell is the cell E _{1 in the} case shown in FIG.
Respectively and C ₁ -C _n corresponding to the base station B ₁ .about.B _n provided for each to E _n.

First, the mobile station in the standby state is notified of the peripheral cell monitoring code as an information element of the notification information through the downlink control channel. For example, the base station B ₁ provided in the cell E ₁ to the mobile station are in the cell E _1, the cell E
Spreading code C ₂ ~ for cells E ₂ ~ E ₇ around ₁
C ₇ is reported respectively.

Next, the mobile station performs despreading on the spread codes C _{2 to} C ₇ that have been informed while sequentially switching the codes of the correlators, and compares the peak reception levels to determine the presence of the mobile station. The reception level from the base station of the cell other than the cell (hereinafter, simply referred to as the own cell),
Consider the cell transition by comparing the reception level of those cells with that of the own cell.

Further, the mobile station during communication, spreading codes for the cell E ₂ to E ₇ around the own cell E ₁ through the control channel during communication immediately after establishing a communication channel C ₂ -C ₇
Is notified. Then the mobile station, spreading code C ₂ is the notification by using the reception level measurement circuit for cell determination -C ₇
Are sequentially scanned, and they are compared with each other to consider cell transition.

CDMA using such a spreading code
In a cell system, interference from other mobile stations is equivalent to noise in conventional communication and is important in determining capacity, and if there are mobile stations and base stations transmitting and receiving with uselessly large power. However, the interference given to the communication of other mobile stations is increased, and the communication quality is deteriorated.

That is, in order to improve the communication quality to the prescribed level, it is necessary to reduce the number of mobile stations that can be simultaneously connected, which causes a problem that the subscriber capacity is reduced.

A detailed description will be given below with reference to FIG.
In FIG. 8, a state in which the mobile station ma1 existing in the cell E ₁ moves into the cell E ₂ is shown as a mobile station ma2. Also,
Since the mobile station mb already exists in the cell E ₂ ,
_It shall communicate with the _second base station B ₂ .

First, the mobile station ma1 in the cell E ₁ is the base station B.
While moving in the state of communication with ₁ , move into cell E ₂ .
At this time, due to the reason that the scan frequency of the cell is suppressed and the scan interval is set to be long, the accurate determination of the cell is delayed, and the mobile station ma and the base station B ₁ reach the position of the mobile station ma2. It is assumed that communication between them is continued. At this time, the mobile station ma2 controls the transmission power so that an appropriate reception power level can be obtained for communication with the base station B ₁ , so that the base station B ₂ acts as a large interference. Therefore, the communication with the mobile station mb is affected, and the subscriber capacity is substantially reduced.

Further, in the conventional cell determination method, a channel to which a different code (in the case of CDMA) is assigned for cell determination, that is, a perch channel is set, and each mobile station has Measure all reception levels of the perch channels (broadcast channels) that belong to the cell, compare all of the measured reception levels, and which base station cell your station belongs to ) Was determined.

[0018]

However, in the CDMA system by spread spectrum, each channel is distinguished by a spread code and all communication is performed using the same frequency, so that all communication waves interfere with each other. The received signal of the desired spreading code and the received wave of another spreading code (that is, the interference wave) have different cross-correlation magnitudes. The error with the reception level becomes large, and the magnitude of the reception wave level may be reversed when compared with the levels of the reception waves from other cells. Therefore, there has been a problem that the frequency of erroneously selecting a base station increases. Further, when the base station is erroneously selected, the transmission output due to the control of the transmission power becomes unnecessarily large, which has a drawback that it becomes a strong interference source for other communications. As a result, there is a problem that the number of stations that can be simultaneously connected decreases and the subscriber capacity decreases.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a mobile communication cell determination method and apparatus capable of finding a perch channel having a higher reception level in a short time.

[0020]

In order to achieve the above object, the first invention of the present application is to provide between a base station provided for each cell and a mobile station moving in an area composed of a plurality of cells. A mobile communication cell determining method in mobile communication for performing code division multiplex communication, wherein the mobile station selects a base station most suitable for communication when the mobile station is in a simultaneous connection state with a plurality of base stations. The gist is that the determination is performed in the cell code scanning order in which the priority order is provided.

Further, the second invention of the present application is a mobile communication system for performing code division multiple communication between a base station provided for each cell and a mobile station moving in an area constituted by a plurality of cells. A communication cell determination method, wherein when the mobile station is in a simultaneous connection state with a plurality of base stations, the mobile station selects a cell determination frequency for selecting an optimal base station for communication. The point is that the cell code scan order is increased.

Further, the third invention of the present application is a mobile communication in mobile communication for performing code division multiple communication between a base station provided for each cell and a mobile station moving in an area composed of a plurality of cells. A method of determining a communication cell, wherein when the mobile station is simultaneously connected to a plurality of base stations and a peripheral cell monitoring code is notified from the plurality of base stations, the mobile station is the optimum base station for communication. The gist is that the cell determination for selecting is performed by scanning only the code commonly included in the notified peripheral cell monitoring codes.

The fourth invention of the present application scans a plurality of cells according to a cell code notified from a base station provided for each cell, selects a base station most suitable for communication, and communicates with the base station. A mobile station device for a mobile station that performs code division multiplex communication in which communication means for performing simultaneous connection with the plurality of base stations when the plurality of base stations can be simultaneously connected, and the communication means In the cell code scanning order set by the priority order setting means for setting the cell code scanning order for prioritizing the cell code common to the cell codes respectively obtained from the plurality of base stations via the cell code scanning order set by the priority order setting means. The gist is to have a scanning means for scanning a cell code.

Further, the fifth invention of the present application scans a plurality of cells according to a cell code notified from a base station provided for each cell, selects a base station most suitable for communication, and communicates with the base station. A mobile station device for a mobile station that performs code division multiplex communication in which communication means for performing simultaneous connection with the plurality of base stations when the plurality of base stations can be simultaneously connected, and the communication means Priority order setting means for setting a cell code scan order with an increased scanning frequency of the cell code common to the cell codes respectively obtained from the plurality of base stations via the cell code, and the cell code set by the priority order setting means The gist of the present invention is to have a scanning unit that performs cell code scanning in a scanning order.

The sixth invention of the present application scans according to a cell code notified from a base station provided for each cell of a plurality of cells, selects a base station most suitable for communication, and communicates with the base station. A mobile station device for a mobile station that performs code division multiplex communication in which communication means for performing simultaneous connection with the plurality of base stations when the plurality of base stations can be simultaneously connected, and the communication means It is characterized in that it has a selecting means for selecting a code common to the peripheral cell monitoring codes respectively notified from the plurality of base stations via the and a scanning means for scanning only the code selected by the selecting means. .

[0026]

In the mobile communication cell determining method of the first invention of the present application, since the cell determination is performed in the cell code scanning order in which the priority order is set, the mobile station can efficiently select the optimum base station for communication. it can.

The mobile communication cell determining method according to the second aspect of the present invention efficiently performs the cell determination in the cell code scanning order in which the scanning frequency of the priority code is increased, so that the mobile station is the optimum base station for communication. Can be selected.

In the mobile communication cell determining method according to the third aspect of the present invention, the peripheral cell monitoring common to the peripheral cell monitoring codes notified from the plurality of base stations when the mobile station is in the simultaneous connection state with the plurality of base stations. When the code is included, by scanning only the common code, it is possible to efficiently perform the cell determination for selecting the optimum base station for communication in an extremely short time.

The mobile station apparatus according to the fourth invention of the present application simultaneously connects with a plurality of base stations capable of simultaneous connection through communication means, obtains cell codes from the respective base stations, and from the plurality of base stations. By performing the cell code scan according to the cell code scan order that gives priority to the cell code common to the cell codes of, the cell determination for selecting the optimum base station for communication can be efficiently performed in a short time.

The mobile station device of the fifth invention of the present application simultaneously connects with a plurality of base stations capable of simultaneous connection through communication means, obtains cell codes from the respective base stations, and obtains the cell code from the plurality of base stations. By performing the cell code scan according to the cell code scan order in which the frequency of scanning the cell code common to the cell codes is increased, the cell determination for selecting the optimum base station for communication can be efficiently performed in a short time. .

In the mobile station device of the sixth invention of the present application, when the peripheral cell monitoring code common to the peripheral cell monitoring codes notified from the plurality of base stations via the communication means includes the common cell monitoring code, the common code is selected by the selecting means. By selecting and scanning only the selected code, it is possible to efficiently perform the cell determination for selecting the optimum base station for communication in an extremely short time.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a main part of a communication channel to which the mobile communication cell determining method according to the present invention is applied.

As shown in FIG. 1, the mobile station apparatus of this embodiment has a first communication channel 1A and a second communication channel 1B.
And a designated channel reception level detector, and the output ends of these communication channels 1A and 1B are connected to the signal synthesizing circuit 3, respectively. Since the configurations of the first communication channel 1A and the second communication channel 1B are the same, the configuration will be described by taking the first communication channel 1A as an example.

This first communication channel 1A is an antenna
Ant., First detector 11A, first correlator 13A, first
The spread code generator 15A, the first demodulator 17A, the first decoder 19A, the first level detector 21A, the first controller 23A, and the signal separation circuit 24A are included. Further, the antenna Ant., The first detector 11A, the first correlator 13A, the first demodulator 17A, and the first decoder 1
9A are connected in series, and further the first decoder 19A
Is connected to the signal separation circuit 24A. The output of the signal separation circuit 24A is connected to the first controller 23A and the signal synthesis circuit 3. The first correlator 13A is also connected to the first level detector 21A, and the first level detector 21A, the first controller 23A, and the first spreading code generator 15A are connected in series. Further, the first spreading code generator 15A is connected to the first correlator 13A.

Next, the operation of the first communication channel 1A will be described. First, a signal received via the antenna Ant. Is extracted by the first detector 11A, for example, a signal in a predetermined band by a bandpass filter, and is output to the first correlator 13A. In the first correlator 13A, the first
The signal input from the detector 11A and the spread code generated by the first spread code generator 15A are correlated and despread, and a primary modulated signal is output.

The spread code generated by the first spread code generator 15A is normally a spread code for a communication channel designated from the base station to the mobile station via the control channel.

The modulated signal despread by the first correlator 13A and output is demodulated by the first demodulator 17A and output. The demodulated signal output from the first demodulator 17A is decoded and error-corrected by the first decoder 19A,
It is input to the signal separation circuit 24A. This signal separation circuit 2
In 4A, the control channel information multiplexed in the communication channel is separated, input to the first control unit 23A, and the communication channel information is output to the signal synthesizing circuit 3.

Next, the designated channel reception level detector 30
Will be described. The designated channel reception level detecting section 30 includes a third correlator 31 and a third spreading code generator 3.
3, a third reception level detector 32, and a third controller 34.

Next, a basic reception level measuring operation of the designated channel reception level detecting section 30 will be described. The signal received through the antenna ANT has the third detection output.
Is input to the correlator 31 of. In the third correlator 31, the spread code generated by the third spread code generator 33 is used for correlation, and the correlator output is the third reception level detector 32.
Entered in. The detected reception level is sent to the third control unit 34. The spreading code generated by the third spreading code generator 33 is usually based on the peripheral cell monitoring spreading code notified from the base station to the mobile station via the control channel. That is, the spreading code for peripheral cell monitoring is the spreading code of the perch channel of the peripheral cell, and the general control unit notifies the third control unit of the spreading code information.

The correlation with these spreading codes is sequentially obtained by the third correlator 31, and the third reception level detector 32 detects the reception level. The detected reception level is associated with the spreading code of the perch channel of the peripheral cell by the third control unit, and by comparison, the perch channel with the maximum reception level, that is, the optimum base station for communication is selected. It

In the above description, the case where the peripheral cell reception level is detected using the designated channel reception level detection unit 30 has been described, but if the first or second communication channel is available, that channel is used. It is also possible to perform reception level measurement. That is, when the mobile station is communicating with one base station using the first communication channel, the neighboring cell reception level can be measured using the second communication channel.
If you are making simultaneous connections with multiple base stations,
Since you are using both communication channels of
The reception level of the peripheral cells is the specified channel reception level detection unit 3
It will be measured at 0.

The spreading code for peripheral cell monitoring transmitted via the above-mentioned control channel is received and decoded by both or one of the first and second communication channels, separated from the communication channel information, and controlled respectively. The data is transferred from the units 23A and 23B to the integrated control unit 25. In the integrated control unit 25,
The reception level measurement prioritization as described below is performed, and the control of the first or second communication channel circuit or the designated channel reception level detection unit 30 that performs peripheral cell monitoring is notified.

Next, with reference to FIG. 2, an outline of the operation of the entire cell code scanning device of this embodiment will be described. First,
In the state a shown in FIG. 2A, the mobile station m communicates with the base station α, which is optimal for communication, via the first communication channel 1A. When the mobile station m moves and reaches the boundary between the base station α and the base station β (state b), communication with the base station β is started, and two or more mobile stations are present at the time of cell transfer. A so-called soft handover state is established in which simultaneous connection is made with the cell site (base station). In this soft handover state, communication with the base station α is performed via the first communication channel 1A, and communication with the base station β is performed via the second communication channel 1B. At this time, the first spreading code generator 15A generates the spreading code C1 corresponding to the base station α, and the second spreading code generator 15B generates the spreading code C2 corresponding to the base station β.
Is generated, and simultaneous reception becomes possible. The received signals are signal-synthesized by the signal synthesizing circuit 3 to ensure a good reception state.

Further, in the state b when the mobile station m moves,
Communication with the base station β is performed via the second communication channel 1B. At this time, communication with the base station α, which has been performed via the first communication channel 1A, is terminated. The communication with the base station β may be performed by so-called space diversity by using the first communication channel 1A which is vacated by the communication with the base station α being terminated.

Next, with reference to FIGS. 2 to 5, a procedure for finding a perch channel having a higher reception level in a short time by setting priorities at the time of cell code scanning will be described.

First, the base station α is transmitted via the common control channel.
After the control signal is transmitted between the mobile station m and the mobile station m and the channel is designated, the communication channel between the mobile station m and the base station α is established in step S11, and the base station α transmits to the mobile station m in step S13. The peripheral cell monitoring code information [C ₁ , C
₃ , C ₁₀ , C ₉ , C ₈ , C ₇ ] is notified. This notified cell code is, as shown in FIG.
It is a cell code preset in each cell existing around the cell having.

In step S15, the peripheral cell code scan is repeatedly performed in the order of C ₁ → C ₃ → C ₁₀ → C ₉ → C ₈ → C ₇ according to this code information (step S 15).
15-S17). When the cell shift is detected by this scan (step S17), the process proceeds to step S19, and soft handover processing, specifically, simultaneous reception with two base stations by two communication channels is started.

When in the soft handover state (step S19), as shown in FIG. 3 (or state b shown in FIG. 2B), a plurality of base stations, for example, in the case of FIG. 3, base station α and base station β are used. The peripheral cell monitoring code information is notified from. For example, the mobile station m which is simultaneously connected to the base station α and the base station β uses the neighboring cell monitoring codes from the base station α to C ₁ , C ₃ , C ₁₀ , C ₉ , C ₈ , C.
_{7 From} base station β to C ₂ , C ₃ , C ₄ , C ₅ , C ₆ , C
₇ is notified (step S21).

Next, the scanning priority is set with reference to the two sets of peripheral cell monitoring codes. As a method of setting the priority of this scan, check the number of codes commonly appearing in the notified peripheral cell monitoring codes,
The code with a large number is set to be scanned with higher priority. This is because the peripheral cell monitoring codes respectively notified from the two base stations are the cell codes of the peripheral cells of the respective base stations, so the code commonly appearing in these two peripheral cell monitoring codes is This is because it is a code corresponding to a cell existing in the area between the base stations, and thus the mobile station has a high probability of transitioning to the area between the two base stations. Also, if the number of appearing items is the same, it is set to scan with the same priority.

Therefore, since the codes C ₃ , C ₇ , C ₁ , C ₂ , C ₄ , C ₅ , C ₆ , C ₈ , C ₉ , C _{10 are} 2 2 1 1 1 1 1 1 1 1, The priority of C ₃ and C ₇ is set to be high, and the other is the same and set to be low (step S23). As a method of increasing the priority, a cell code having a high priority is brought to the beginning of the scan order to accelerate the scan order (see FIG. 4).
(See (a)) and a method of increasing the scan frequency by arranging the scan order a plurality of times in one cycle of the scan order (see FIG. 4B).
There is. In addition, in FIG. 4B, it can be considered that the scan order is made faster and the scan frequency is made higher.

Next, in step S25, the cell code scan is repeatedly performed in the scan order in which the scan order of the cell code with high priority is advanced and the scan frequency is increased. Then, in step S27. When the cell transfer is detected by the scan, the process proceeds to step S29 and a new soft handover process is performed.

As a result, the monitoring order of cells having a higher transition probability becomes faster, and the frequency increases, so that the cell transition can be detected quickly.

When the soft handover of the old base station is canceled due to the cell change, the cell code corresponding to the base station is deleted from the priority.

For example, in the above example, as shown in FIG. 6, after the base station α is transferred to the base station β and the soft handover state is set, the reception level of the base station α changes as the mobile station m moves. A case is shown in which the soft handover state is ended by dividing the threshold value and only the base station β communicates.

Next, a method for detecting cell transition more quickly will be described. In the above-described embodiment, all the notified peripheral cell monitoring codes are scanned, but in the present embodiment, the cell code commonly included in the peripheral cell monitoring codes notified from a plurality of base stations is selected by the selecting means. Only the cell code selected and selected by this selecting means is scanned. This is similar to the above embodiment, because the cell corresponding to the peripheral cell monitoring code commonly notified from a plurality of base stations is a cell existing in the area between the plurality of base stations, This is because the stations have a very high probability of transitioning the area between these base stations. In this way, when only the common cell code is scanned, in the above-described embodiment, only 2 cell codes out of 10 cell codes are scanned, and the search time is simply shortened to 1/5. .

In the above embodiment, the case of applying to CDMA has been described as an example, but the present invention is not limited to this and any communication capable of simultaneous connection with two or more cells. Can be applied to the scheme.

[0057]

As described above, according to the present invention, the priority is set when the cell code is scanned. Therefore, it is possible to efficiently find a perch channel having a high reception level in a short time. Play.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of a mobile communication cell determination device according to the present invention.

FIG. 2 is a diagram for explaining the operation of the mobile communication cell determining device shown in FIG.

FIG. 3 is a diagram for explaining the operation of the mobile communication cell determination device shown in FIG.

FIG. 4 is a diagram for explaining the operation of the mobile communication cell determination device shown in FIG.

5 is a flowchart schematically showing the operation of the mobile communication cell determination device shown in FIG.

FIG. 6 is a diagram for explaining priorities.

FIG. 7 is a diagram for explaining a cell code.

FIG. 8 is a diagram for explaining a conventional problem.

[Explanation of symbols]

 1 Communication Channel 3 Signal Combining Circuit 11 Detector 13 Correlator 15 Spreading Code Generator 17 Demodulator 19 Decoder 21 Level Detector 23 Control Unit 30 Specified Channel Reception Level Detection Unit 31 Third Correlator 32 Third Reception Level Detector 33 Third spreading code generator 34 Third control unit

Claims (6)

[Claims] 1. A mobile communication cell determination method in mobile communication for performing code division multiplex communication between a base station provided for each cell and a mobile station moving in an area composed of a plurality of cells. , When the mobile station is in a state of simultaneous connection with a plurality of base stations, the mobile station performs cell determination for selecting an optimal base station for communication in a cell code scan order provided with a priority order. Mobile communication cell determination method. 2. A mobile communication cell determination method in mobile communication in which code division multiplex communication is performed between a base station provided for each cell and a mobile station moving in an area composed of a plurality of cells. In a cell code scan order in which the mobile station is in a simultaneous connection state with a plurality of base stations, the mobile station selects a cell base for selecting the most suitable base station for communication in order to prioritize the code scanning frequency. A method for determining a mobile communication cell, which is characterized by performing. 3. A mobile communication cell determination method in mobile communication in which code division multiplex communication is performed between a base station provided for each cell and a mobile station moving in an area composed of a plurality of cells. , When the mobile station is in the simultaneous connection state with a plurality of base stations, when the peripheral cell monitoring code is notified from the plurality of base stations, cell determination for the mobile station to select the optimal base station for communication Is performed by scanning only the code commonly included in the notified peripheral cell monitoring codes. 4. A plurality of cells are scanned according to a cell code notified from a base station provided for each cell, a base station most suitable for communication is selected, and code division multiplex communication is performed with the base station. A mobile station device of a mobile station, wherein the communication means performs simultaneous connection with the plurality of base stations when the plurality of base stations are simultaneously connectable, and the plurality of bases via the communication means. Priority order setting means for setting a cell code scanning order that gives priority to a cell code common to the cell codes respectively obtained from the stations, and scanning means for performing cell code scanning in the cell code scanning order set by the priority order setting means. And a mobile station device. 5. A plurality of cells is scanned according to a cell code notified from a base station provided for each cell, a base station most suitable for communication is selected, and code division multiplex communication is performed with the base station. A mobile station device of a mobile station, wherein the communication means performs simultaneous connection with the plurality of base stations when the plurality of base stations are simultaneously connectable, and the plurality of bases via the communication means. Priority order setting means for setting a cell code scan order that increases the scan frequency of the cell code common to the cell codes obtained from each station, and cell code scan in the cell code scan order set by this priority order setting means. A mobile station device, comprising: a scanning unit for performing. 6. A plurality of cells is scanned according to a cell code notified from a base station provided for each cell, a base station most suitable for communication is selected, and code division multiplex communication is performed with the base station. A mobile station device of a mobile station, wherein the communication means performs simultaneous connection with the plurality of base stations when the plurality of base stations are simultaneously connectable, and the plurality of bases via the communication means. A mobile station device comprising: a selection unit for selecting a code common to the peripheral cell monitoring codes notified from the stations, and a scanning unit for scanning only the code selected by the selection unit.