JPH09307942A - Mobile station equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a mobile station equipment capable of measuring a received electric field strength of base stations other than the opposite base station during communication to reduce the required time for measuring the received electric field strength of all the base stations. SOLUTION: An RSSI measurement section 200 measures the received electric field strength of base stations other than a calling base section. An RSSI measurement table update section 201 updates the name of the base stations and their reception electric field strength in a RSSI measurement table 10. A peripheral base station information table update section 203 updates a peripheral base station table 11 in the order of reception electric field strength based on the RSSI measurement table 10. A mobile destination base station detection section 204 references a peripheral measurement base station table 12 to detect a base station with a highest reception electric field strength higher than the equipment electric field strength of the base station of the opposite communication party. A supervisory base station changeover section 205 selects a base station of a succeeding supervisory object based on the peripheral measurement base station table 12 and the RSSI measurement section 200 again starts the means of the reception electric field strength of the base station.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a mobile station apparatus used in a service area formed by a plurality of base stations to which radio channels having different frequencies are assigned.

[0002]

2. Description of the Related Art In recent years, with the advancement of advanced information technology, mobile communication systems having excellent immediacy and functionality have been attracting attention, and mobile phones,
It is realized in various forms such as a car phone and an MCA radio. In Japan, the PHS (Personal Handyphone System; second-generation cordless telephone) service started in 1995. PCS (Per
Sonal Communications Serv
Ice) standardization work is in progress. PCS is a digital cordless service that enables not only voice but also multimedia wireless communication of images and images, and 7 types of schemes are planned to be adopted. Among them, PACS is regarded as the most promising method. PACS is Bellcore
WACS (Wireless-Accesses)
It is based on the s-Communication System). The radio frequency band used is 1.9 GHz band, and the frequency interval is 300 kHz.
However, the TDMA method is used as the access method, the FDD method is used as the transmission method, and the DQSPSK method is used as the modulation method, and the transmission speed is relatively high at 32 kbps as compared with the conventional cellular system, for example. It has the advantages of good sound quality, suitable for data communication, and low equipment cost such as base station. PA
The CS constitutes a service area with a large number of wireless zones like the PHS in Japan. Therefore, when the mobile station apparatus approaches a radio zone of another base station while continuing communication with a certain base station, the mobile station apparatus switches the radio link to the new base station. This function is called the handover function. The handover function allows the user to move within the area of the wireless zone without disconnecting communication.

Now, it is the base station specifying process that becomes a problem to smoothly perform the handover function. The base station identification process is a process of identifying the base station that can receive the radio wave with the highest sensitivity among the many base stations existing in the service area. Through this identification processing, the base station determined to have good sensitivity is determined as the handover destination. Japanese Patent Laid-Open No. 01-303
Japanese Laid-Open Patent Publication No. 817 introduces a mobile communication device related to this base station identification processing. According to the publication, the mobile station measures the electric field strength of each base station in the service area for a predetermined time and averages the measurement results. The reason why the average calculation is necessary is to cancel the variation in the received electric field strength due to the influence of obstacles in the surroundings, and the accuracy of the measurement is improved by performing the average calculation several times. Repeating this average calculation for all base stations in the service area reveals the strength of the radio waves of each base station. Therefore, the mobile station can know which base station has the highest sensitivity. When the sensitive base station is found, the mobile station performs a handover to the base station. By such base station identification processing, the mobile station can perform handover to the base station in the best state. Even when the mobile station is in the standby state (the standby state is a state in which the mobile station waits for an incoming call addressed to itself by monitoring the paging channel). By repeating the measurement and averaging them, which base station has the highest sensitivity is observed.

[0004]

However, in the base station identification process in the prior art, the average calculation is repeated for all the base stations, so that it takes a lot of time to identify the base station with high sensitivity. If the mobile station moves during the average calculation as described above, an inappropriate base station may be selected as a handover destination. When the mobile station device is moving at a relatively high speed, this phenomenon appears significantly,
A mobile station device passes by and selects a base station far away from the current position as a handover destination.

An object of the present invention was made in view of the above circumstances, and it is an object of the present invention to provide a mobile station which can shorten the calculation time of the average received electric field strength and can find a sensitive base station in a short time. It depends on

[0006]

According to the present invention, the measurement of a base station whose received electric field strength is weak is interrupted midway.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION To achieve the above object, the invention according to claim 1 moves within a service area in which radio zones of a plurality of base stations to which radio channels having different frequency bands are allocated are combined. , A mobile station device that sequentially selects a radio channel having a high received electric field strength when moving and performs data communication with a base station to which the radio channel is assigned, and stores the radio channel assigned to each base station. The channel storing means, the selecting means for selecting one of the stored channels other than the one currently in communication, the measuring means for measuring the received electric field strength in the selected channel for a unit time, Monitoring means for monitoring whether or not the received electric field strength falls below a predetermined threshold, and when the received electric field strength falls below a predetermined threshold, the selecting means is caused to select the channel. The channel skip means for erasing and selecting another channel, the integrating means for integrating the measurement results per unit time by the measuring means as long as the received electric field strength exceeds a predetermined threshold, and the measurement per unit time is predetermined. When repeated, the confirming means for confirming the integrated value as the measurement result, the comparing means for comparing the received electric field strength given by the confirmed integrated value with the received electric field strength in the channel currently in communication, and the integrated value If it is determined that the received electric field strength given by is greater than the received electric field strength, the channel switching means for switching the communication channel from the currently communicating channel to the radio channel selected by the selecting means, and the received electric field given by the integrated value When it is determined that the intensity is smaller, the selecting means is provided with selecting means for selecting another channel. Are those that were,
The mobile station device is moving within a service area in which radio zones of a plurality of base stations to which radio channels having different frequency bands are assigned are combined. The channel storage means stores the wireless channel assigned to each base station. One of the stored channels other than the one currently being communicated is selected by the selecting means. The measuring means measures the received electric field strength in the selected channel for a unit time. The monitoring means monitors whether or not the received electric field strength during the measurement falls below a predetermined threshold value. When the received electric field strength falls below a predetermined threshold value, the selection of that channel by the selection means is canceled by the channel skip means, and another channel is selected. As long as the received electric field strength exceeds the predetermined threshold value, the measurement results per unit time by the measurement unit are integrated by the integration unit. When the measurement per unit time is repeated a predetermined number of times, the integrated value is fixed as the measurement result by the fixing means. The reception electric field strength given by the determined integrated value and the reception electric field strength in the channel currently in communication are compared by the comparison means. When it is determined that the received electric field strength given by the integrated value is larger, the channel switching unit switches the communication channel from the currently communicating channel to the wireless channel selected by the selecting unit. When it is determined that the received electric field strength given by the integrated value is smaller, the selecting means causes the selecting means to select another channel.

In the invention according to claim 2, the increase / decrease amount calculating means for calculating the increase / decrease amount of the received electric field strength measured by the measuring means for each channel, and whether the calculated increase / decrease amount has an increasing tendency or not. The selecting unit includes a determining unit that determines whether the channel has a decreasing tendency and a deleting unit that deletes the channel having the decreasing tendency from the channel storing unit. The selecting unit selects the channel from the channel storing unit in which the channel has been deleted by the deleting unit. The increase / decrease amount of the received electric field strength measured by the measuring means is calculated for each channel by the increase / decrease amount calculating means. The determining unit determines whether the calculated increase / decrease amount has an increasing tendency or a decreasing tendency. The channel having a decreasing tendency is deleted from the channel storing means by the deleting means. From the channel storage means in which the channel was deleted by the deletion means,
The channel is selected by the selection means.

Further, the mobile station apparatus according to claim 3 further comprises a detecting means for detecting whether or not the communication in the channel is completed, and a selecting means for selecting a channel having a higher received electric field strength measured from the channel storing means. Writing means for writing the selected channel to the backup memory, determining means for determining whether or not the standby state has started, and storing the backup channel in the backup memory when it is determined that the standby state has started. The present invention is characterized by comprising a reading means for reading the existing channel into the channel storage means, and the detection means detects whether or not the communication in the channel is completed. A channel having a higher received electric field strength measured by the selection means is selected from the channel storage means. The channels selected by the writing means are written in the backup memory. The determination means determines whether or not the standby state has started. When it is determined that the standby state has started, the reading means reads the channel stored in the backup memory into the channel storage means.

(First Embodiment) FIG. 1 is a system configuration diagram in the present embodiment. Base stations 2 to 2 in FIG.
Channels 4 are assigned different channels, and the mobile station apparatus 1 is connected to the base station 2 by a radio link. The wireless zones 5-7 correspond to the base stations 2-4. The number of peripheral base stations is three in this figure, but in the case of PACS, a maximum of 50 stations is the target.

The base stations 2 to 4 are bundled together by a base station controller 8 which is connected to a public network 9 (ISDN / PSTN or the like) to perform input / output via the public network. The mobile station device 1 includes an input unit 100, an output unit 101, a communication control unit 102, a modulation unit 103, a demodulation unit 104, a radio control unit 105, and an antenna 106.

The input unit 100 is composed of a push key, a microphone, etc., and inputs data such as a dial number and voice to the communication control unit 102. The output unit 101 is composed of a display device, a speaker, and the like, and stores, displays, and outputs the data output from the communication control unit 102. The communication control unit 102 includes a CPU, a ROM,
Includes RAM, etc. to control the entire mobile station.

The modulator 103 modulates the transmission data output from the communication controller 102 by a predetermined method (for example, π
/ 4 shift DQPSK modulation) and output to radio control section 105. The demodulation unit 104 demodulates the signal received by the wireless control unit 105 and gives it to the communication control unit 102.

The radio control section 105 mixes the modulated data supplied from the modulation section 103 with the reference clock signal and transmits it from the antenna 106, and the high frequency signal induced in the antenna 106 with the reference clock signal. A receiver 31 for extracting only a predetermined band, a transmitter 30, and a first frequency synthesizer 33 and a second frequency synthesizer 34 for providing the receiver 31 with two kinds of clock signals, that is, first and second reference clock signals.

The first reference clock signal is a clock signal for establishing a wireless link and communicating with the base station. Since the communication with the base station is performed by the time division multiplex method, the first reference clock signal by the first frequency synthesizer 33 is
It is given to the transmitting unit 30 and the receiving unit 31 only during the period in which the upstream and downstream time slots addressed to the own device are transmitted. The second reference clock signal is used to perform a base station specifying process, and is used to check the received electric field strength of a base station other than the one being used in the wireless link among the base stations around the current position. Since the communication with the base station is performed by the time division multiplexing method, the second reference clock signal by the second frequency synthesizer 34 is
It is given to the transmission unit 30 and the reception unit 31 other than the period in which the upstream and downstream time slots addressed to the own device are transmitted.

Further, the radio control section 105 is provided with a base station specifying section 107 which performs a base station specifying process. The base station specifying unit 107 measures the received electric field strength of surrounding base stations and specifies the handover destination base station. In the example of FIG. 1, assuming that the wireless link is established on the base station 2, the base station identifying unit 107 measures the received electric field strength of the base stations 3 and 4 in the vicinity.

In FIG. 1, the mobile station apparatus 1 when the zone 5 of the base station 2 is separated from and the zone 6 of the base station 3 is approached.
Will be described. Radio control unit 1 of mobile station device 1
05 and the communication control unit 102 detect that the received electric field strength of the base station 3 is higher than that of the base station 2 of the current communication partner.
Since the received electric field strength of the base station 3 tends to increase, the mobile station device 1 switches the wireless link used for communication from the base station 2 to the base station 3.

The internal configuration of the base station identification unit 107 will be described with reference to FIG. The base station identification unit 107 shown in FIG.
Is an RSSI measurement table 10 and peripheral base station information table 1
1, measurement base station table 12, RSSI measurement unit 200, RS
The SI measurement table updating unit 201, peripheral base station information table updating unit 203, destination base station detecting unit 204, and monitoring base station switching unit 205 are included.

In FIG. 2, the RSSI measurement table 10 has columns for describing all base stations scattered within the service area (CS3, in the figure, as indicated by reference numeral a1 in FIG. 2).
It is described as CS4, CS5. ), And a column describing the average of the received electric field strength of the base station, which is provided for describing the received electric field strength measurement result. Similar to the RSSI measurement table 10, the peripheral base station information table 11 has columns for describing all the base stations scattered in the service area (indicated as CS3, CS4, CS5 in the figure), and their columns. Consisting of a field describing the average of the received electric field strength of the base station,
While the RSSI measurement table 10 is provided for describing the received electric field strength measurement result, the peripheral base station information table 1
In No. 1, the order of the individual base stations is rearranged in order of magnitude of the received electric field strength. That is, the peripheral base station information table 11 is provided for rearranging the order of base stations.

The measurement base station table 12 indicates all the base stations scattered in the service area (indicated as CS3, CS4, CS5 in the figure, as indicated by reference numeral a3 in FIG. 2). ,) And the radio channels used by those base stations are described in association with each other. The measurement base station table 12 is
It is used to describe the base station whose received field strength is to be measured.

The RSSI measuring unit 200 uses the second frequency synthesizer 34 to determine the radio channel set as the monitoring target.
And the intensity of the signal output from the receiving unit 31 is measured per unit time. If this is repeated a predetermined number of times, RSSI
The measuring unit 200 calculates the average value of the measurement results. The monitoring target refers to one of the wireless channels used in the service area, which is the target of intensity measurement, and is switched by the monitoring base station switching unit 205. For example, 1895.150Hz, 1895.450Hz, 1895.750H within the service area
z, 1896.050Hz, 1896.350Hz, 1896.650Hz, 1896.950Hz
When wireless channels such as ... Are used, these are sequentially selected for monitoring. For details of the measurement of the received electric field strength, refer to "Japanese Patent Laid-Open No. 01-
Please refer to them because it is described in various documents including "JP-A No. 303817".

The RSSI measurement table updating unit 201 writes the average value calculated by the RSSI measurement unit 200 in the RSSI measurement table 10. Peripheral base station information table updating unit 203
Based on the RSSI measurement table 10, the order of the base stations described in the peripheral base station information table 11 is rearranged in the order of the received electric field strength.

The movement-destination base station detection unit 204 stores the measurement results of the base stations described in the peripheral base station information table 11,
The strength of the received electric field strength of the base station with which the mobile station is currently communicating is determined. The strength determination by the movement-destination base station detection unit 204 is performed by comparing the received field strength of the base station currently in use with the RSSI.
This is performed by comparing the measured value of the received electric field strength of the base station in the measurement table 10. If a base station having a received electric field strength higher than that of the base station currently in communication is described in the measurement base station table 11, the movement-destination base station detection unit 204
Indicates the base station as a handover destination.

The monitoring base station switching unit 205 switches the monitoring target base stations one after another within the range described in the measurement base station table 12. The switching of the monitoring target by the monitoring base station switching unit 205 is performed under the following first and second conditions. The first condition is a case where the received electric field strength for the base station is measured by a predetermined number of samples, and the second condition is
This is the case where the received electric field strength less than the threshold is measured during the measurement. If the first and second conditions are satisfied during the measurement of the received electric field strength, the monitoring base station switching unit 205 switches the monitoring target to another base station.

FIG. 3 is a flow chart of the base station specifying unit 107 in the first embodiment. In this flowchart, the sample number Np is a variable for setting the upper limit of the sample number in the average calculation, and the variable SUM is a variable for accumulating the received electric field strength RSSI. In the flowchart of FIG. 3, in steps S1 to S5, the variable CNT is the number of samples Np.
A loop process is repeated until the value of the measurement base station table 12 is reached.
Form a loop process that is repeated for all base stations described in.

The mobile station device 1 is in communication with the base station 2. In step S1, the RSSI measuring unit 200 measures the received electric field strength RSSI of a base station that is a monitoring target for a unit time among the base stations currently located around the mobile station apparatus.
After execution of step S1, it is determined in step S2 whether or not the number of samples is equal to Np, and if not, the variable CNT is incremented by 1 in step S3. Subsequent step S
In 4, the received electric field strength RSSI of the base station is added to the variable SUM (SUM ← SUM + RSSI). After the addition, the process proceeds to step S5, and it is determined whether the received electric field strength RSSI is equal to or more than the threshold. If it is equal to or more than the threshold value, the process proceeds to step S1. Received field strength
If RSSI is always equal to or more than the threshold value, steps S1 to S5 are repeated. In this repetition, in step S4,
Increment the variable CNT by one. Step S
With the increment of 4, the variable CNT gradually increases, and the received electric field strength RSSI is integrated with the variable SUM.
When the value of the variable CNT reaches the variable Np2 (that is, when the first condition is satisfied), step S2 becomes Yes and the process proceeds to step S6.

Although the above operation is the same as the base station specifying process of the prior art, the feature of the present embodiment is that it is determined in step S5 whether the received electric field strength RSSI is greater than or equal to the threshold value, and the received electric field strength RSSI is If less than the threshold, step S6
(This is the second condition described above.). That is, when it is less than the threshold value, the processing including steps S1 to S4 is interrupted midway.

In step S6, the RSSI measuring section 200 is activated. The activated RSSI measuring unit 200 receives the received electric field strength.
SUM / variable CNT is calculated to average the received electric field strength RSSI, and the average value is written in the base station column in the RSSI measurement table 10 in step S7. After writing, the process proceeds to step S8. In step S8, the monitoring base station switching unit 205 is activated. The monitoring base station switching unit 205 reads out another base station information from the measurement base station table 12, and sets the radio channel of the base station information to the RSSI measuring unit 200.
Set to. As a result, the RSSI measuring section 200 measures the strength of another wireless channel. By switching in step S8, the wireless channels of the base stations described in the measurement base station table 12 are sequentially set in the RSSI measurement unit 200, and the average value of the received electric field strengths thereof is calculated.
Step S9 is an end judgment of the loop processing, and the base station read in step S8 is the measurement base station table 12
Is positioned at the end of the list. While the base station near the head of the list written in the measurement base station table 12 is being read, step S9 is No, and thus the process proceeds to step S11. In step S11, these variables are cleared to zero by substituting 0 for the variables CNT and SUM, and the process proceeds to step S12. Since the measurement of the received electric field strength for one base station is completed, the peripheral base station information table updating unit 203 is activated in step S12. Peripheral base station information table updating unit 203 uses RSSI
Based on the information in the measurement table 10, the base stations listed in the peripheral base station information table 11 are rearranged in the order of the received electric field strength. By this rearrangement, a new rank is given to the base stations listed in the peripheral base station information table 11. In step S13, the movement-destination base station detection unit 20
4 is activated. The movement-destination base station detection unit 204 refers to the arranged peripheral base station information table 11 and determines whether or not there is a base station in the peripheral base station information table 11 that has a higher received electric field strength than the base station of the current communication destination. .

When the base station located at the end of the list is read, the answer is Yes in step S9, the process proceeds to step S10, and the read destination of the base station information is returned to the top of the list.
In the iterative processing in steps S1 to S13, when a measurement result having a value higher than that of the currently used base station is obtained, step S13 becomes Yes and the process proceeds to step S14. In step S14, handover is started to the base station having the maximum received electric field strength.

As described above, according to the present embodiment, the base station whose received electric field strength is less than the threshold value is interrupted by the up / down determination in step S5 and the measurement target is switched to another base station. Since the useless measurement is interrupted on the way due to the interruption, the time required for the measurement of the peripheral base stations is significantly shortened. (Second Embodiment) In the second embodiment, it is devised to preferentially measure a base station in which the result of the received electric field strength tends to increase. FIG. 4 is a configuration diagram of the mobile station device 1 according to the second embodiment. Referring to this figure, the base station approach detection unit 4 is added to the internal configuration of the base station identification unit 107 shown in FIG.
It can be seen that 00 is newly added.

The base station approaching detection section 400 operates in step S6.
In the above, when the RSSI measurement table updating unit 201 calculates the average of the received electric field strength of one base station, the increase / decrease amount of the received electric field strength stored in the RSSI measurement table is calculated, and it is determined whether the increase / decrease amount has an increasing tendency. . The base station determined to have the received electric field strength increasing tends to remain in the peripheral base station information table 12. The base station determined to be in the decreasing tendency is deleted from the peripheral base station information table 12. Due to this deletion, the reception field strength is focused on the base station whose reception field strength tends to increase. Base station approach detection unit 400
The process will be described in more detail.

FIG. 5 is a diagram showing an example of the movement route of each base station, its radio zone, and the mobile station device 1. The mobile station device 1 passes along the moving route 13 from the radio zone 5 of the base station 2 to the radio zone 7 of the base station 3 toward the radio zone 6 of the base station 4. In addition, the graph of FIG. 6 shows a change in the received electric field strength received by the mobile station device 1 according to the distance from the base station by a straight line (actually, the received electric field strength is the distance 2).
It is a curve because it is inversely proportional to the power, but it is expressed simply as a straight line here. ).

This straight line has a portion drawn with a thick line,
Although separated from the portion drawn by the thin line, the portion shown by the thick line is measured by the RSSI measuring unit 200, and the thin line is not measured. Since the straight line of the base station 2 is a thick line between the points A and B, the base station 2
Is measured, but the base stations 3 and 4 are not measured. Point B
Between points C and C, since the straight lines of the base stations 3 and 4 are thick, the base stations 3 and 4 are measured and the base station 2 is not measured.

The operation of the mobile station apparatus according to the second embodiment will be described with reference to the graph of FIG. Mobile station device 1
While moving from point 0 to point A, the average of the received electric field strength of the base station 4 is calculated by the base station identification process in the flowchart of FIG. 3 and written in the RSSI measurement table 10 ( Step S7). After this writing, the base station approach detection unit 400 is activated. The base station approach detection unit 400 calculates the increase / decrease amount of the received electric field strength at the time of measurement of the base station 4, and determines whether the received electric field strength of the base station 4 tends to increase. Since the sensitivity of the base station 4 tends to increase between the points 0 to A, the base station approach detection unit 400 re-registers the base station 4 in the measurement base station table 12.

While the mobile station apparatus 1 is moving from the point 0 to the point A, the RS in the base station specifying process in the flowchart of FIG.
The SI measurement table updating unit 201 calculates the average of the received electric field strength of the base station 3 and writes it in the RSSI measurement table 10 (step S in the flowchart of FIG. 3).
7). After this writing, the base station approach detection unit 400 is activated. The base station approach detection unit 400 calculates the increase / decrease amount of the base station 3 and determines whether the received electric field strength of the base station 3 tends to increase. Between point 0 and point A, the received electric field strength of the base station 3 tends to increase, so the base station approach detection unit 40
0 re-registers the base station 3 in the measurement base station table 12.

While the mobile station device 1 is moving from the point A to the point B, the base station specifying process in the flowchart of FIG.
The RSSI measurement table updating unit 201 calculates the average of the received electric field strength of the base station 2 and writes it in the RSSI measurement table 10 (step S7). After this writing, the base station approach detection unit 400 is activated. Base station approach detection unit 4
00 calculates the increase / decrease amount of the base station 2 and determines whether the received electric field strength of the base station 2 tends to increase. Point 0 to Point A
During this period, the sensitivity of the base station 2 tends to decrease, so the base station 2 in the measurement base station table 12 is deleted.

Since the base station 2 has been deleted in the measurement base station table 12, the base station identification processing while moving from the point B to the point C is performed for the base stations 3 and 4. Be seen. When the sensitivity of the base station 3 increases at the point C, this is determined in step S13, and the base station 3 is determined as the handover destination in step S14.

As described above, according to the second embodiment, the measurement of the received electric field strength is limited to the base stations whose received electric field strength tends to increase, so that the handover destination can be specified earlier. (Third Embodiment) The mobile station apparatus of the third embodiment is configured to store, as a backup, a base station for which the measurement result of the received electric field strength is high after communication is completed. Therefore, in the third embodiment, in addition to the internal configuration of the mobile station apparatus shown in FIG. 1, the standby target base station storage unit 14 shown in FIG.
And a backup management unit 108.

The standby target base station storage unit 14 is realized by a non-volatile memory or the like, and stores a table (standby target base station table) for storing the standby target. An example of this stand-by target base station table is shown in FIG. The standby target is a base station that is a target of the base station identification processing in the standby state, and all the base stations described in the standby target base station storage unit 14 are stored in the measurement base station table 12. Transferred. By this transfer, the base station that is the target of the received electric field strength measurement in the standby state is set. Since the standby target base station storage unit 14 is realized by a non-volatile memory or the like, the stored contents are not lost even when the mobile station device 1 is powered off.

The backup management unit 108 realizes the backup function by the processing of the flowchart of FIG. The processing contents of the backup management unit 108 will be described with reference to this flowchart. Step P
In step 1 and step P2, the backup management unit 108 monitors whether the standby state process has started or whether the communication using the wireless link has ended. If the communication using the wireless link ends, the process proceeds to step P5.

In step P5, it is judged whether or not a base station whose measured received electric field strength is equal to or higher than a predetermined threshold is described in the RSSI measurement table 10, and if it exists, it is read from the RSSI measurement table 10 in step P6. hand,
The received electric field strength is written in the standby base station storage unit 14 as a base station of a higher class. As a result, the upper-class base station is backed up. After backing up, the process proceeds to steps P1 and P2. When the operator turns off the power of the mobile station device 1 because the communication is completed, the backup management unit 108
The process of is also interrupted.

It is assumed that the power is turned on again and the backup management unit 108 is activated. At this time, the backup management unit 108 detects the start of the standby state process in the monitoring process in steps P1 and P2. If detected, the process proceeds to step P3, and all the base stations are read from the standby target base station storage unit 14 and written in the measurement base station table 12. After writing, the process proceeds to step P4, and the base station identification unit 107 is activated so as to measure the received electric field strength for the base station written in the measurement base station table 12. As a result, the received electric field strength is measured by the base station identification unit 107 only for the upper-class base stations.

As described above, according to the present embodiment, the target of the received electric field strength measurement is narrowed down to the base station of the upper class, so that the power consumption for the received electric field strength measurement is cut down. As a result, it is possible to monitor the base station efficiently while taking standby power consumption into consideration.

[0044]

According to the mobile station of the first aspect, the measurement of the first channel candidates below the threshold value is interrupted on the way, so that the reception field strength measurement of the first channel candidates with low reception field strength is early. Rounded up. Such rounding up significantly reduces the time required for averaging.
By this shortening, it is possible to identify at an early stage which of the peripheral base stations has the highest average value of the received electric field strength. Therefore, handover with high real-time property can be realized.

According to the second aspect of the present invention, it is possible to detect the base station which is at the destination of the mobile station and is approaching relatively quickly. According to the third aspect of the present invention, it is possible to monitor an efficient base station in consideration of power consumption by monitoring only the base station having a received electric field strength equal to or higher than the threshold value during standby.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a service area and an internal configuration diagram of a mobile station device.

FIG. 2 is a configuration diagram showing an internal configuration of a base station identification unit 107.

FIG. 3 is a flowchart showing the processing contents of a base station identification unit 107 of the mobile station apparatus according to the first embodiment.

FIG. 4 is a base station identification unit 107 according to the second embodiment.
FIG.

FIG. 5 is a movement route diagram of a mobile station device.

FIG. 6 is a reception electric field strength change diagram of the second embodiment.

FIG. 7 is an internal configuration diagram of a mobile station device.

FIG. 8 is a diagram showing an example of a standby base station table.

FIG. 9 is a flowchart showing the processing contents of a base station identification unit 107 of the mobile station apparatus according to the third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mobile station apparatus 2-4 Base station 6 Base station control apparatus 10 RSSI measurement table 11 Peripheral base station information table 12 Measurement base station table 14 Standby target base station storage section 30 Transmission section 31 Reception section 31 33 First frequency synthesizer 34 second frequency synthesizer 100 input unit 101 output unit 102 communication control unit 103 modulation unit 104 demodulation unit 105 wireless control unit 106 antenna 107 base station identification unit 108 backup management unit 200 measurement unit 201 measurement table update unit 203 peripheral base station information table Update unit 204 Destination base station detection unit 205 Monitoring base station switching unit 400 Base station approach detection unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiko Hirose 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. A radio channel which moves within a service area in which radio zones of a plurality of base stations to which radio channels having different frequency bands are allocated are combined, and which selects a radio channel having a high received electric field strength when moving. Is a mobile station device that performs data communication with a base station assigned to the base station, the channel storage means storing the radio channel assigned to each base station, and the current communication from among the stored channels. Selecting means for selecting one channel other than medium, measuring means for measuring the received electric field strength on the selected channel for a unit time, and monitoring means for monitoring whether or not the received electric field strength under measurement falls below a predetermined threshold value If the received electric field strength falls below a predetermined threshold value, the channel skipping procedure that causes the selection means to cancel the selection of that channel and select another channel. And an integrating means for integrating the measurement results per unit time by the measuring means as long as the received electric field strength exceeds a predetermined threshold, and when the measurement per unit time is repeated a predetermined number of times, the integrated value is measured. And a received electric field strength given by the confirmed integrated value,
If it is determined that the comparison means for comparing the received electric field strength in the channel currently being communicated and the received electric field strength given by the integrated value are larger, the communication channel is selected by the selecting means from the currently communicating channel. A mobile station comprising channel switching means for switching to a wireless channel that is present and selection means for causing the selection means to select another channel when it is determined that the received electric field strength given by the integrated value is smaller. apparatus. 2. The mobile station apparatus according to claim 1, further comprising an increase / decrease amount of the received electric field strength measured by the measuring means,
An increase / decrease amount calculating means for each channel, a determining means for determining whether the calculated increase / decrease amount has an increasing tendency or a decreasing tendency, and a deleting means for deleting a channel having a decreasing tendency from the channel storage means. The mobile station apparatus, wherein the selecting means selects a channel from the channel storing means in which the channel is deleted by the deleting means. 3. The mobile station device according to claim 1, further comprising: a detection unit that detects whether or not the communication in the channel has ended, and a selection unit that selects a channel having a higher received electric field strength measured from the channel storage unit. Means, a writing means for writing the selected channel in the backup memory, a judging means for judging whether or not the standby state has started, and a storing means for storing in the backup memory when the standby state has been started. A mobile station device, comprising: a reading means for reading the existing channel into the channel storage means.