JP4256020B2 - Mobile radio terminal and base station selection method in the mobile radio terminal - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mobile radio terminal used as a mobile radio terminal and a base station selection method thereof in a cellular mobile communication system having a paging area such as PHS (Personal Handyphone System).
[0002]
[Prior art]
In the cellular mobile communication system, for example, a system in which a large number of base stations distributed and arranged in a service area, such as PHS, are grouped for each predetermined area and the position management of mobile radio terminals is performed for each of these groups. is there.
[0003]
FIG. 9 shows an example of the configuration, and the base stations are grouped into CS11 to CS1n, CS21 to CS2m,... To constitute areas E1, E2,. Further, the base stations CS11 to CS1n, CS21 to CS2m,... Are accommodated in the mobile communication networks NW1, NW2,... For each group and further connected to each other via the upper network NW. In PHS, the area corresponding to each group is called a general call area.
[0004]
When receiving a call to the mobile radio terminal PSa, all the base stations CS11 to CS1n in the general call area E1 in which the mobile radio terminal PSa is located are transmitted all at once and sent to the mobile radio terminal PSa. An incoming call signal is received. Then, the mobile radio terminal PSa that has received the incoming call signal transmits a link channel establishment request to the source base station (for example, CS12), so that the base station CS12 and the incoming call destination mobile radio terminal PSa A wireless link is formed, and thereafter a predetermined incoming call procedure is performed, and then wireless communication is enabled.
[0005]
On the other hand, when the mobile radio terminal PSa makes a call, an operation of selecting a base station (for example, CS12) that transmits a radio wave having the highest reception level and transmitting a link channel establishment request to the base station CS12 is performed. is there. In this case, the base station CS12 that has received this request assigns a link channel to the mobile radio terminal PSa that is the call source, forms a radio link with the mobile radio terminal PSa, and thereafter performs a predetermined call procedure. Enables wireless communication after going.
[0006]
Further, when the mobile radio terminal PSa moves during communication to switch the connection destination base station, so-called handover is performed, the mobile radio terminal PSa searches for all base stations in the vicinity, and the radio wave having the highest reception level is obtained. Is selected as the handover destination, and a link channel establishment request is transmitted to this base station CS11. Then, the base station CS11 that has received this request assigns a link channel to the requesting mobile radio terminal PSa to form a new radio link with the mobile radio terminal PSa. After performing a predetermined connection switching procedure with the previous base station CS11, the connected base station is switched.
[0007]
That is, when making a call or performing a handover, the mobile radio terminal unconditionally selects the base station with the highest reception level, that is, the base station closest to the mobile radio terminal, A link channel establishment request for handover is transmitted.
[0008]
However, in such a system, for example, when the mobile radio terminal is located near the boundary between a plurality of simultaneous call areas E1 and E2 as shown by PSb in FIG. 9, as a call destination or handover destination base station, The local station PSb may select a base station CS22 that belongs to another general call area E2 that is different from the general call area E1 that is being registered. In this case, a control signal for connection control processing is exchanged between the mobile communication networks NW1 and NW2 via the higher level network NW, which causes the following various problems.
[0009]
That is, since the time required for the connection control process becomes longer by passing through the upper network NW, the communication interruption time becomes longer and the communication quality is deteriorated. For example, since the communication interruption time is generally 2 to 3 seconds or more, depending on the user, it may be mistaken for communication disconnection and the end-of-call operation may be performed. On the other hand, for the telecommunications carrier, the use of the upper network NW for each connection control process increases traffic on the upper network NW and increases the burden on the upper network NW. Also, depending on the telecommunications carrier, there is a case where another company's network is used for the upper network NW. In such a case, each time the connection control process is performed, the other company charges for the running cost. Will increase.
[0010]
[Problems to be solved by the invention]
As described above, in the conventional system, the mobile radio terminal unconditionally selects the base station with the highest reception level as the call destination or handover destination base station. For this reason, for example, when the mobile radio terminal is located near the boundary of a plurality of paging areas, the base station of the paging area that is different from the paging area being registered by the own station is selected and issued. A call or handover may occur. This causes a deterioration in the communication quality of the user, causes an increase in traffic on the upper network and an increase in the running cost of the operator, and is extremely undesirable.
[0011]
The present invention has been made paying attention to the above circumstances, and its object is to improve the communication quality by shortening the time required for connection control processing at the time of calling or handover, and to the connection control processing. An object of the present invention is to provide a mobile radio terminal and a base station selection method thereof that can reduce the burden on the network side.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the present invention groups a plurality of base stations, configures a paging area for each group, performs location registration for each paging area, and includes base stations belonging to the paging area for which the location is registered. In a mobile radio terminal used in a mobile communication system that performs radio connection control with a station,
Search means for searching for a base station capable of receiving a radio signal by monitoring the reception quality of each radio signal transmitted by each base station, and the radio signal reception quality for a plurality of base stations searched by the search means A priority determining means for determining a selection priority based on; The reception quality of the radio signal transmitted from the first base station group belonging to the calling area where the terminal is registered is raised and corrected, and the reception quality of the first base station group after the raising correction and the others The selection priority order of each base station determined by the priority order determination means based on the reception quality of the radio signal transmitted from the second base station group belonging to the paging area And a priority order correcting means for correcting, and a base station selecting means for selecting the base station and performing the wireless connection control according to the selection priority order corrected by the priority order correcting means. is there.
It is a thing.
[0014]
Above raising correction As a specific example of processing, the first base station group Raise reception quality evenly correction What to do and the first base station group Raise the reception quality of the receiver to a larger value as the reception quality is higher correction What to do is conceivable. Also, raise the bottom correction Is a first base station whose reception quality is equal to or higher than a preset value. group Should be done only for.
[0015]
According to the present invention, the first base station group Reception quality and second base station group Or the second base station has the same reception quality as group The reception quality of the first base station group Even if the received quality is slightly higher than the first base station group Reception quality has increased correction By being , First base station group The selection priority of Compared to that of the second base station group It is corrected to be higher. For this reason, as a connected base station, Compared to the second base station group belonging to other calling areas First base station group As a result, it is possible to increase the probability that call processing or handover processing is performed for base stations in the same area.
[0016]
Therefore, the probability that the connection control process is performed via the upper network is reduced, and thereby the average time of the connection control process time is shortened. For this reason, it is possible to shorten the communication interruption time particularly in the handover, thereby improving the communication quality of the user. On the other hand, for the communication carrier, the number of times the upper network is used for the connection control processing is reduced, so that traffic on the upper network can be suppressed and the burden on the network can be reduced. In addition, a communication carrier using another company's network as a host network can reduce the running cost by reducing the communication cost required for the connection control processing.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a circuit block diagram showing a configuration of a PHS terminal which is an embodiment of a mobile radio terminal according to the present invention. Note that the overall configuration of the PHS will be described using the configuration shown in FIG. 9 as an example.
[0018]
The PHS terminal includes a radio unit 1 having an antenna 11, a modem unit 2, a TDMA unit 3, a call unit 4, a control unit 5, an information storage unit 6, a data communication unit 7, and a keypad. And an input unit 8 and a display unit 9 using a liquid crystal display (LCD).
[0019]
That is, a radio carrier signal arriving from a base station (not shown) is received by the antenna 11 and then input to the receiving unit 13 via the high frequency switch (SW) 12 of the radio unit 1. In the receiving unit 13, the received radio carrier signal is mixed with a local oscillation signal generated from the synthesizer 14 and down-converted to a reception intermediate frequency signal. The local oscillation signal frequency generated from the synthesizer 14 is set to a value corresponding to the radio channel frequency according to an instruction from the control unit 5. The radio unit 1 is provided with a received electric field strength detection unit (RSSI) 16. The reception field strength detection unit 16 detects the reception field strength of a radio carrier signal arriving from a communicating base station or a neighboring base station, and the detected value is a control unit for determining and displaying the reception quality, for example. 5 is notified.
[0020]
The received intermediate frequency signal output from the receiving unit 13 is input to the demodulating unit 21 of the modem unit 2. The demodulator 21 digitally demodulates the received intermediate frequency signal, thereby reproducing the digital demodulated signal.
[0021]
The TDMA decoding unit 31 of the TDMA unit 3 separates the digital demodulated signal for each reception time slot. If the data in the separated slot is audio data, the audio data is input to the interface unit 4. On the other hand, if the data of the separated slot is packet data or control data, these data are input to the data communication unit 7.
[0022]
The call unit 4 includes an ADPCM (Adaptive Differential Pulse Code Modulation) transcoder 41, a PCM codec 42, a speaker 43, and a microphone 44. The ADPCM transcoder 41 decodes the audio data output from the TDMA decoding unit 31. The PCM codec 42 converts the digital audio signal output from the ADPCM transcoder 41 into an analog signal, and outputs the audio signal from the speaker 43 in a loud sound.
[0023]
The data communication unit 7 receives the data supplied from the TDMA decoding unit 31 and supplies this data to the control unit 5. If the received data is control data, the control unit 5 analyzes the control data and performs necessary control. On the other hand, if the received data is packet data coming from a server or the like, the packet data is depacketized and then stored in the information storage unit 6 and supplied to the display unit 9 for display.
[0024]
On the other hand, the user's voice signal input to the microphone 44 is PCM-encoded by the PCM codec 42 and further compressed and encoded by the ADPCM transcoder 41. The encoded audio data is input to the TDMA encoding unit 32. Control data and packet data output from the control unit 5 are input to the TDMA encoding unit 32 via the data communication unit 7.
[0025]
The TDMA encoding unit 32 inserts the digital audio data of each channel output from the ADPCM transcoder 41 and the control data and packet data output from the data communication unit 7 into the transmission time slot instructed by the control unit 5. And multiplex. The modulation unit 22 digitally modulates the transmission intermediate frequency signal with the multiplexed digital communication signal output from the TDMA encoding unit 32 and inputs the modulated transmission intermediate frequency signal to the transmission unit 15.
[0026]
The transmission unit 15 mixes the modulated transmission intermediate frequency signal with the local oscillation signal generated from the synthesizer 14, up-converts it to a radio carrier frequency, and further amplifies it to a predetermined transmission power level. The radio carrier signal output from the transmitter 15 is transmitted from the antenna 11 to a base station (not shown) via the high frequency switch 12.
[0027]
Incidentally, the control unit 5 includes, for example, a microcomputer as a main control unit, and includes a handover / call control unit 51 and a priority order data correction unit 52 as control functions according to the present invention.
[0028]
Of these, first, the handover / call control means 51 measures the reception levels (RSSI values) of radio carrier wave signals from a plurality of neighboring base stations at the time of calling and handover, respectively. A base station is searched, and the selection priority for the searched neighboring base stations is determined based on the reception level. Then, based on the determined selection priority data, an optimal base station is selected as a call destination or a handover destination, and a radio link channel is established with the selected base station, and then call control or Perform handover control.
[0029]
The priority order data correction means 52, when determining the selection priority order of the neighboring base stations in the handover / call control means 51, positions of its own PHS terminals are registered at the present time for the plurality of searched neighboring base stations. It is divided into a first base station group belonging to the general paging area and a second base station group belonging to the other general paging area. Then, each reception level of the first base station group is corrected by raising based on the correction data of the reception level correction table prepared in advance, and the selection priority order of each base station is determined based on the reception level after this elevation correction. decide.
[0030]
Next, a handover control operation and a call control operation of the PHS terminal configured as described above will be described. FIG. 2 is a flowchart showing the control procedure and control contents of the control unit 5.
[0031]
That is, during communication, a PHS terminal (for example, PSb) detects the reception level of a radio carrier signal arriving from a connected base station (for example, CS11) in step 2a, and this detection value of the reception level is a preset threshold. It is determined whether or not the value has fallen below the value. When the reception level detection value (RSSI value) falls below the threshold value, it is determined that handover is necessary, and the process proceeds to step 2c. First, the neighboring base stations are searched. This search for neighboring base stations uses the idle slot period to detect the reception level (RSSI value) of the radio carrier signal arriving from each neighboring base station, and search for neighboring base stations that are higher than the connectable level. This is done by extracting.
[0032]
Next, the PHS terminal PSb proceeds to step 2d, where data representing the selection priority of the connection destination base station is created. FIG. 3 is a flowchart showing the selection priority order data creation processing procedure and processing contents.
[0033]
That is, first, in step 3a, the control unit 5 identifies, based on the search results of the neighboring base stations obtained in step 2c, the identification information (CS-ID) and reception levels (RSSI values) of all the searched neighboring base stations. ) Is created to represent the combination. For example, if base stations CS12, CS13, CS21, CS22, and CS23 are searched as neighboring base stations as shown in FIG. 5, the CS-IDs of these neighboring base stations CS12, CS13, CS21, CS22, and CS23 are The combination data of the RSSI value is created and stored in the information storage unit 6.
[0034]
Next, the control part 5 extracts CS-ID and RSSI value of arbitrary surrounding base stations (for example, CS12) from the said combination data at step 3b. Then, in step 3c, the neighboring base station CS12 determines whether or not its own PHS terminal PSb is included in the first base station group corresponding to the simultaneous call area E1 whose location is being registered. As a result of the determination, if the extracted neighboring base station CS12 is included in the first base station group, the process proceeds to step 3d and based on the reception level correction table stored in advance in the information storage unit 6. Correct the RSSI value.
[0035]
For example, if data as shown in FIG. 4 is stored as a reception level correction table and the RSSI value of the neighboring base station CS12 is 40 dBμV in this state, the RSSI value of the neighboring base station CS12 is 50 dBμV. It is corrected. Also, if the extracted RSSI value of the neighboring base station CS13 is 50 dBμV, which is a larger value, the RSSI value of the neighboring base station CS13 is corrected to 64 dBμV. The wavy lines shown in FIG. 5 indicate the RSSI values of the peripheral base stations CS12 and CS13 after the correction.
[0036]
Here, the correction characteristic of the reception level in this embodiment is set so that the RSSI correction amount (the amount of increase) increases as the RSSI value increases as shown in FIGS. This makes it easier to select a base station in the area where the PHS terminal is located so that the base station with a higher RSSI value has a higher selection priority, while the base station with a lower RSSI value has a lower priority for selection. This is because a neighboring base station having a high RSSI value is selected as much as possible regardless of the in-service area and the other areas.
[0037]
On the other hand, if the extracted neighboring base station is included in another simultaneous call area E2 such as the base stations CS21 to CS23, the control unit 5 does not perform the RSSI value correction process and does not perform step 3e. Migrate to That is, the RSSI value is not corrected for the neighboring base stations belonging to the other general paging areas as in the base stations CS21 to CS23 of FIG.
[0038]
When the RSSI value correction processing for one extracted neighboring base station is completed, the control unit 5 proceeds to Step 3e, where the RSSI value after correction and other neighboring base stations are transferred to the base station. The selection priority is given by comparing with the RSSI value of the station. In step 3f, it is determined whether or not extraction has been performed for all of the searched plurality of neighboring base stations. If there are unextracted neighboring base stations, the process returns to step 3b. The RSSI value correction process and the selection priority assignment process by 3e are performed. Thereafter, the RSSI value correction process and the selection priority assignment process are repeated for each extracted neighboring base station until there is no unextracted neighboring base station.
[0039]
When the necessity determination of the RSSI value correction for all the searched neighboring base stations CS12, CS13, CS21, CS22, and CS23 and the correction processing when correction is necessary are completed, the control unit 5 connects to the connection destination in step 3g. Priority data for selecting a base station is created. For example, when the RSSI values after correction of the neighboring base stations CS12, CS13, CS21, CS22, and CS23 have a relationship as shown in FIG. 5, the selection priority is set as indicated by the circled numbers 1-5. The
[0040]
When the creation of the selection priority data is completed, the control unit 5 proceeds to step 2e, where the base station with the highest priority is selected as the handover destination base station based on the selection priority data. Then, a procedure for establishing a radio link channel with the selected base station is executed. For example, in the example shown in FIG. 5, the base station CS13 in the general call area E1 is selected, and a radio link channel establishment control procedure is performed with the base station CS13. Then, when the handover link base station CS13 is connected via the radio channel by the radio link channel establishment control procedure, the control unit 5 shifts from step 2f to step 2h and thereafter executes the handover procedure. .
[0041]
On the other hand, when the radio link channel cannot be established with the base station CS13 having the highest priority, the control unit 5 proceeds to step 2g and uses the selection priority data as a basis. The base station with the second highest priority is selected as the handover destination base station, and a procedure for establishing a radio link channel with the selected base station is executed. For example, in the example shown in FIG. 5, the base station CS23 in the general call area E2 is selected, and a radio link channel establishment control procedure is performed with the base station CS23.
[0042]
In this case, connection control signals are exchanged between the mobile communication networks NW1 and NW2 via the host network NW. However, since the PHS terminal PSb is connected to the base station CS23 having the highest reception level, the wireless channel is not disconnected after the connection, and the S / N is good and high-quality wireless communication is ensured. The
[0043]
Although the case of handover has been described above, the same applies to the case of outgoing calls. However, in the case of a call, the user's call operation is monitored in step 2i as shown in FIG. Subsequent processing procedures and processing contents are the same as the handover control procedures and control contents described above.
[0044]
As described above, in this embodiment, at the time of a handover and a call, a neighboring base station is searched, and among the obtained neighboring base stations CS12, CS13, CS21, CS22, CS23, its own PHS terminal PSb For the base stations CS12 and CS13 belonging to the general call area E1 whose location is being registered, the RSSI value is corrected by raising according to the reception level correction table. Then, according to the corrected RSSI value, a selection priority is assigned to each of the searched neighboring base stations, and the base station CS13 having the first selection priority is selected to establish a radio link channel. I have to.
[0045]
Therefore, as shown in FIG. 5, for example, the base station CS23 having a higher reception level than the base stations CS12 and CS13 belonging to the simultaneous call area E1 in which the terminal PSb is registered is located in the other general call area E2. Even if it exists, the selection priority of the base station CS13 is corrected to be higher than that of the base station CS23 by the above-mentioned bottom-up correction. Therefore, the PHS terminal PSb can establish the radio link channel by selecting the base station CS13 in the general call area E1 for which location registration is being performed as the first priority for selection.
[0046]
Accordingly, in this case, the connection control process can be performed without going through the upper network NW, and the time required for the connection control process is thereby shortened. For this reason, the communication interruption time in the handover can be shortened, thereby improving the communication quality of the user.
[0047]
On the other hand, since it is possible for the communication carrier to perform connection control processing without going through the upper network NW, the traffic on the upper network NW can be suppressed and the burden on the network side can be reduced. In addition, a communication carrier using another company's network as the upper network NW can reduce the running cost by reducing the communication cost required for the connection control processing.
[0048]
Further, in the present embodiment, the reception level correction characteristic is set so that the RSSI value increases as the RSSI value increases as shown in FIGS. By doing so, the base station having a larger RSSI value can have a higher priority for selection, whereby the PHS terminal PSb can preferentially select the base station in the general call area E1 whose location is being registered. it can. On the other hand, since the lower the RSSI value, the lower the selection priority, the higher the RSSI value, regardless of whether the PHS terminal PSb is in the area E1 location registration or the other area E2. The peripheral base station can be selected, and thereby the connection stability of the radio channel can be kept higher.
[0049]
The present invention is not limited to the above embodiment. For example, the correction characteristic for increasing the reception level is set so that the increase value increases in proportion to the reception level only for a base station whose reception level is equal to or higher than the predetermined level L1, as shown in FIG. May be. By using such correction characteristics, it is possible to correct the reception level up only for a base station whose reception level exceeds a level effective as a connection destination.
[0050]
Further, as shown in FIG. 7, the correction characteristic of the reception level is set to zero or a minimum value for a base station whose reception level is lower than the predetermined level L1, and the reception level is equal to or higher than the predetermined level L2. The base station may be set so as to uniformly give the maximum bottom-up value.
[0051]
Further, as shown in FIG. 8, the reception level correction characteristic may be set so that a preset increase value is uniformly given to all base stations regardless of the magnitude of the reception level.
[0052]
Further, in the above embodiment, the selection priority is relatively increased by correcting the reception level of the first base stations CS12 and CS13 belonging to the general call area E1 during the location registration, but instead, the selection priority is increased. The selection priority of the first base stations CS12 and CS13 may be relatively increased by reducing the reception level of the second base stations CS21, CS22, and CS23 belonging to the general call area E2. Further, both the reception level raising process of the base station in the registered general call area E1 and the reception level reduction (cut off) process in the other general call areas E2, E3,. Thus, the reception level may be corrected.
[0053]
Further, in the above embodiment, the reception level (RSSI value) of the radio carrier signal from the neighboring base station is detected as information indicating the reception quality, and the selection priority is determined based on this information. Alternatively, the frame error ratio (FER) of the signal received from 1 may be detected as data representing the reception quality, and the selection priority order may be determined based on this data. Alternatively, both the RSSI value and the FER may be detected, the reception quality may be determined based on the detection results, and the selection priority may be determined based on the determination results.
[0054]
Further, in the above embodiment, the PHS has been described as an example, but the present invention can be applied to other systems as long as the mobile communication system forms a common area by a plurality of base stations. In addition, various modifications can be made to the circuit configuration of the mobile radio terminal, the control procedure and contents of handover and call, the procedure and contents of the selection priority determination means and the correction means, and so on without departing from the scope of the present invention. Can be implemented.
[0055]
【The invention's effect】
As described above in detail, in the present invention, a plurality of base stations located around the own apparatus are searched by monitoring reception qualities of radio signals transmitted from the respective base stations. In the mobile radio terminal for determining the selection priority based on the reception quality, selecting an appropriate base station as a connection destination according to the determined selection priority and executing the radio connection control, Priority order correction means is newly provided. And by this selection priority order correction means, The reception quality of the radio signal transmitted from the first base station group belonging to the paging area where the own terminal is registered is raised and corrected, and the reception quality of the first base station group after the correction is increased, Based on the reception quality of the radio signal transmitted from the second base station group belonging to the calling area, the selection priority order of each determined base station is corrected. Like to do.
[0056]
Therefore, according to the present invention, a mobile radio terminal capable of improving the communication quality by shortening the time required for connection control processing at the time of calling or handover, and reducing the load on the network side related to the connection control processing. And its base station selection method.
[Brief description of the drawings]
FIG. 1 is a circuit block diagram showing a configuration of a PHS terminal which is an embodiment of a mobile radio terminal according to the present invention.
FIG. 2 is a flowchart showing a procedure and control contents of handover and call control by the control unit of the PHS terminal shown in FIG. 1;
FIG. 3 is a flowchart showing a selection priority order data creation processing procedure and processing contents in the control procedure shown in FIG. 2;
FIG. 4 is a diagram showing an example of a reception level correction table.
FIG. 5 is a diagram showing an example of reception level and selection priority order determination results from neighboring base stations.
FIG. 6 is a diagram illustrating an example of correction characteristics.
FIG. 7 is a diagram illustrating another example of correction characteristics.
FIG. 8 is a diagram showing another example of reception level and selection priority order determination results from neighboring base stations.
FIG. 9 is a schematic diagram illustrating an example of the configuration of a PHS.
[Explanation of symbols]
NW ... Upper network
NW1, NW2 ... Mobile communication network
E1, E2 ... Simultaneous call area
CS11 to CS1n, CS21 to CS2m ... base station
PSa, PSb ... Mobile radio terminal (PHS terminal)
1 ... Radio section
2. Modem part
3 ... TDMA section
4 ... Calling part
5. Control unit
6. Information storage unit
7. Data communication part
8 ... Input section
9 ... Display section
11 ... Antenna
12 ... High frequency switch (SW)
13: Receiver
14 ... Synthesizer
15 ... Transmitter
16: Received electric field intensity detector (RSSI)
21. Demodulator
22: Modulation section
31 ... TDMA decoding section
32 ... TDMA encoding section
41 ... ADPCM transcoder
42 ... PCM codec
43 ... Speaker
44 ... Microphone
51. Handover / calling control means
52. Priority order data correction means

Claims (5)

Multiple base stations are grouped, a paging area is configured for each group, location registration is performed for each paging area, and wireless connection control is performed for base stations belonging to the paging area where the location is registered In mobile radio terminals used in communication systems,
Search means for searching for a base station capable of receiving a radio signal by monitoring the reception quality of the radio signal transmitted by each base station,
Priority order determining means for determining a selection priority order based on reception quality of radio signals for a plurality of base stations searched by the search means;
The reception quality of the radio signal transmitted from the first base station group belonging to the calling area where the terminal is registered is raised and corrected, and the reception quality of the first base station group after the raising correction and the others Priority correction means for correcting the selection priority of each base station determined by the priority determination means based on the reception quality of the radio signal transmitted from the second base station group belonging to the paging area ; ,
A mobile radio terminal comprising: base station selection means for performing radio connection control by selecting a base station in accordance with the selection priority order corrected by the priority order correction means. The priority correction means, the reception quality of the first base station group uniformly raised corrected, the reception quality of the raised corrected first and the second base station group and the receiving quality of the base station group 2. The mobile radio terminal according to claim 1, wherein the selection priority order of each base station is corrected based on the base station. The priority correction means, the reception quality of the first base station group and raised corrected by a larger value the higher the reception quality, the second base and the reception quality of the first base station group after this bottom-up correction The mobile radio terminal according to claim 1, wherein the selection priority of each base station is corrected based on the reception quality of the station group. 2. The mobile radio terminal according to claim 1, wherein the priority order correcting unit performs correction for raising the reception quality of a first base station group having a reception quality equal to or higher than a preset value. Multiple base stations are grouped, a paging area is formed for each group, location registration is performed for each paging area, and wireless connection control is performed for base stations belonging to the paging area where the location is registered In a mobile radio terminal base station selection method used in a communication system,
By monitoring the reception quality of radio signals transmitted by each base station, search for base stations that can receive radio signals,
The selection priority is determined based on the reception quality of the radio signal for the plurality of searched base stations,
The reception quality of the radio signal transmitted from the first base station group belonging to the paging area where the own terminal is registered is raised and corrected, and the reception quality of the first base station group after the correction is increased, Based on the reception quality of the radio signal transmitted from the second base station group belonging to the calling area, the selection priority order of each determined base station is corrected ,
A base station selection method for a mobile radio terminal, wherein the radio connection control is performed by selecting a base station according to the corrected selection priority.

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