JP3270994B2 - Mobile terminal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses the current idle time of control channel reception of a base station to receive a control channel of another base station and determines the level of a received signal. And a portable terminal such as a PHS or a cellular phone in which the switching time is reduced by previously searching for a portable terminal.

[0002]

2. Description of the Related Art For example, a PHS terminal always receives a control channel transmitted from a base station at predetermined time intervals and stands by. Therefore, when the PHS terminal moves and the reception level of the control channel falls below a certain level (area information holding zone holding level), it becomes impossible to wait. The PHS terminal determines that the zone is outflow, executes a control channel monitor, selects a new base station satisfying the standby zone holding level of the area information, establishes a control channel again, and enters a standby state.

[0003]

However, as described above, when the conventional PHS terminal moves out of the zone when moving (when the reception level of the control channel falls below a prescribed level), it becomes impossible to wait, and once, The standby state is cut off, the control channel monitor is periodically executed, a new base station having a high reception level is searched and selected, and a control channel is established again with the base station, so that it takes several seconds. Accordingly, there has been a problem that if an incoming call signal arrives during this time, or if a call is originated from the user, connection with the base station is disabled.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a portable terminal which eliminates the above-mentioned problems and can quickly re-establish a control channel with another base station when a zone flows out during movement. With the goal.

[0005]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention connects to the base station by periodically receiving a control channel transmitted by the base station, and establishes connection with the base station at a reception level. If the holding level is lower than the holding level necessary for maintaining, the mobile terminal that searches for another base station having a high reception level, switches to the base station, and uses it, as shown in FIG. A background monitor for receiving a control channel of another base station using the idle time of the control channel reception, and setting a background monitor start level for activating the background monitor when the reception level is reduced; The ground monitor start level is set higher than the hold level, and the reception level of the control channel of the base station is set to the background monitor level. If the received signal level is lower than the start level, the background monitor is detected and the background monitor is started, and the background monitor searches for and stores a candidate base station whose reception level is equal to or higher than the holding level, or receives the received signal by the background monitor. Means for maintaining the state, and for switching the base station to the candidate base station when the reception level of the control channel of the base station falls below the held level.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings using a PHS terminal which is one of portable terminals. FIG. 2 is a diagram showing a receiving operation of the PHS terminal of the present invention. As shown in the figure, the PHS terminal connects to the base station and determines the reception level at every battery saving synchronization (every 1200 ms in the current PHS) via the control channel, but the processing time is about 625 μs and most of the processing time is about 625 μs. The time is in an idle state (empty time). The PHS terminal of the present invention uses this idle time as a background monitor process, determines the reception level of the control channel of another base station, and prepares for the outflow of the zone of the current base station when moving.
The processing for selecting a candidate base station is performed in advance.

FIG. 3 is a diagram showing a configuration example of a PHS terminal of the present invention. As shown, the PHS terminal of the present invention includes an antenna 1, a transmitting / receiving unit 2, a modulator 3, a demodulator 4, an audio signal processing unit 5, a microphone 6, a speaker 7, an operation unit 8, a CPU (central processing unit) 9, ROM (Read Only Memory) 10
And a random access memory (RAM) 11.

At the time of reception, the signal received by the antenna 1 is amplified by the transmission / reception unit 2, demodulated by the demodulator 4, subjected to frame processing and decoding processing by the audio signal processing unit 5, and subjected to speaker 7.
Is output as audio. At the time of transmission, the audio signal converted into an electric signal by the microphone 6 is subjected to encoding processing and frame processing by the audio signal processing unit 5 and is modulated by the modulator 3.
The signal is amplified by the transmission / reception unit 2 and transmitted from the antenna 1.

An operation unit 8 is a man-machine interface unit for dial operation and the like, and a CPU (central processing unit) 9 processes signals from each unit and issues an instruction to control the whole. A ROM (read only memory) 10 is a memory for storing those control programs, and a RAM (random access memory) 11 is a memory for storing data.

FIG. 4 is a diagram showing an example of a module configuration of the PHS terminal of the present invention. As shown, the PHS of the present invention
The terminal includes a communication module 41 of a radio unit, a control channel module 42, a call control module 43, and a communication module 44 of a man-machine interface. The control program of each module is stored in the ROM 10, and a candidate base station table 42-1 for storing the selected candidate base station is provided in the RAM 11.

The control channel module 42 includes protocol software 42-2 for performing control channel monitoring processing,
It has a candidate base station table 42-1 that stores candidate base stations, and performs processing related to transmission and reception of control signals. The call control module 43 performs processing related to call control, mobility management, and wireless management. The communication module 41 performs communication processing with the transmission / reception unit 2, and the communication module 44 performs man-machine interface processing.

FIG. 1 is a diagram showing a reception level judgment processing flow of the PHS terminal of the present invention. The determination of the reception level is performed using the burst signal of the control channel. Here, level a represents the background monitor start level, and level b represents the standby zone holding level of the area information.

First, a burst signal of the control channel is read (step ST11). It is determined whether the reception level is lower than level a (step ST12). If the reception level is lower, it is further determined whether it is lower than level b (step S12).
T13) If it is higher, the control channel monitor reads the burst reception of the control channel of another base station and monitors the signal level (step ST14). If there are a plurality of candidate base stations at the time of the judgment so far, the reception level is reduced. Rearranged in order of size and stored in the candidate base station table 42-1 (step S
T15).

In step ST13, if the reception level of the current base station is lower than level b, it is determined whether or not a candidate base station can be selected in the candidate base station table 42-1 (step ST16). If again,
The control channel monitor reads the burst reception of the control channel of another base station and monitors the signal level (step S
T17), it is determined whether or not there is a base station to select (step ST18). If there is no base station to select, it is determined that there is no base station nearby, and zone loss is stored (step ST18).
19).

In step ST16, it is determined whether or not a candidate base station can be selected in the candidate base station table 42-1 (step ST16). If the candidate base station can be selected, or if the candidate base station is found in step ST18. If so, an attempt is made to re-establish a control channel with the base station (step S
T20) If the establishment fails, it is determined that there is no base station nearby, and the zone loss is stored (step ST21). If successful, base station change processing is performed and stored (step ST2).
2). If a zone leaks out, the control channel establishment process (another program) is started periodically as before,
The control channel is re-established immediately after entering the service area of any base station.

FIG. 5 is a diagram showing the movement of the PHS terminal and the signal level of each base station. As shown in the figure, a level a (background monitor start level) higher than the level b indicating the standby zone holding level of the conventional area information is set. PHS terminals are base station A, base station B, base station C
When the mobile terminal moves through the service area as shown by the arrow D, the background monitor is activated when the mobile station leaves the base station A,
A candidate base station is selected in the order of base station C and base station B, and stored in the candidate base station table 42-1.

When the PHS terminal moves and the base station A leaves the zone, the control channel can be switched immediately since the base station B has already been selected. If the reception levels of the respective base stations are stored and processed in chronological order, it is possible to easily determine which base station is approaching and to select a more appropriate base station. The background monitor sets a timer and executes the timer at an appropriate frequency, thereby preventing an increase in power consumption and suppressing battery consumption.

As described above, according to the first embodiment, the level a (background monitor start level) higher than the level b indicating the standby zone holding level of the conventional area information is set and the current base station is set. When the reception level of the control channel falls below level a, another candidate base station is searched for and selected in advance by the background monitor, so that when the reception level falls below level b and zone loss occurs, another base station is immediately set up. Can be switched to

[Embodiment 2] FIG. 6 is a flowchart showing another reception level judgment processing flow of a PHS terminal which is one of the portable terminals of the present invention. The determination of the reception level is performed using the burst signal of the control channel. Here, the control channel 2 represents a control channel of another base station being received by the background monitor. Level a represents the background monitor start level, and level b represents the standby zone holding level of the area information.

First, a burst signal of the control channel is read (step ST61). It is determined whether or not the reception level is lower than level a (step ST62). If the reception level is lower, it is further determined whether or not the reception level is higher than level b (step ST63). Check whether channel 2 is being received (step S
T64) If it is not receiving, control channel (control channel 2) of another base station is received and the reception level is determined (step ST65).

It is determined whether the reception level has reached level b and can be used as a candidate base station (step ST6).
6) If possible, register as control channel 2 on the background monitor and start receiving. Step ST63
If the reception level is lower than the level b, it is determined whether or not the control channel 2 is being received by the background monitor (step ST68). If the reception is being performed, the reception of the current control channel 1 is stopped (step ST69). ), The base station of control channel 2 is switched to the base station of control channel 1 (step ST70).

If control channel 2 is not being received in step ST68, a base station as control channel 1 is searched for (step ST71). It is determined whether or not a candidate base station has been selected (step ST72). If the candidate base station has been selected, the base station is registered as control channel 1 and reception is started (step ST73), and no candidate base station was selected. In this case, it is determined that there is no base station nearby, and the zone loss is stored (step ST74). When a zone flows out, the control channel establishment process (another program) is started periodically as in the conventional case, and the control channel is re-established immediately upon entering the service area of any base station.

FIG. 7 is a diagram showing the movement of the PHS terminal and the signal level of each base station. As shown in the figure, a level a (background monitor start level) higher than the level b indicating the conventional area information standby zone holding level is set. When the PHS terminal moves through the service area of the base station A and the base station B as shown by the arrow E, the background monitor is activated when the mobile station exits the level a of the base station A, selects the base station B, and sets the background. The reception is started as the control channel 2 on the monitor.

Since the control channel of the base station B has already been received by the background monitor when the level drops below the level b of the base station A and flows out of the zone, it is only necessary to switch this as the control channel in use. Is done. The background monitor is executed by a timer at an appropriate frequency, thereby preventing an increase in power consumption and suppressing battery consumption.

As described above, according to the second embodiment, the level a (background monitor start level) higher than the level b indicating the standby zone holding level of the conventional area information is set, and the current base station is set. When the reception level of the control channel becomes lower than level a, the background monitor searches for another base station and starts receiving. Therefore, the current reception level of the control channel of the base station becomes lower than level b, and zone loss occurs. When you do, you can switch immediately.

[0026]

As described above, according to the present invention, the following excellent effects are expected. A background monitor for receiving control channels of other base stations using idle time as software of the mobile terminal is provided, and the background monitor start level is set higher than the holding level,
Detecting that the reception level of the control channel has fallen below the background monitor start level, activating the background monitor, searching for and storing candidate base stations whose reception level is at or above the holding level in the background monitor, or A means for switching the base station to the candidate base station when the mobile terminal moves and the reception level of the control channel becomes lower than the holding level while holding the reception state with the background monitor, Since the candidate base station has already been determined at the time when the zone is lost, there is no need to search for the candidate base station from the time when the zone is lost as in the conventional case, and the switching time is shortened. The chance of being disabled is also reduced.

[Brief description of the drawings]

FIG. 1 is a flowchart of a reception level determination process of a PHS terminal according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a receiving operation of the PHS terminal of the present invention.

FIG. 3 is a diagram illustrating a configuration example of a PHS terminal of the present invention.

FIG. 4 is a diagram showing an example of a module configuration of a PHS terminal of the present invention.

FIG. 5 is a diagram illustrating the movement of a PHS terminal and the signal level of each base station.

FIG. 6 is a flowchart of a reception level determination process of the PHS terminal according to the second embodiment of the present invention.

FIG. 7 is a diagram illustrating the movement of a PHS terminal and the signal level of each base station.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 antenna 2 transmission / reception unit 3 modulator 4 demodulator 5 audio signal processing unit 6 microphone 7 speaker 8 operation unit 9 CPU (central processing unit) 10 ROM (read only memory) 11 RAM (random access memory) 41 communication module 42 control channel Module 42-1 Candidate base station table 42-2 Protocol software 43 Call control module 44 Communication module

Claims (1)

(57) [Claims] 1. A method for connecting to a base station by periodically receiving a control channel transmitted by the base station, wherein a reception level is lower than a holding level required to maintain a connection with the base station. A mobile terminal that searches for another base station having a high reception level, switches to the base station, and uses the base station by using the idle time of control channel reception as software for the mobile terminal to receive a control channel of another base station. Providing a background monitor, setting a background monitor start level for activating the background monitor when the reception level decreases, setting the background monitor start level higher than the holding level, and controlling a control channel of the base station. If the reception level is lower than the background monitor start level, it is detected and the background level is detected. A monitor is started, and the background monitor searches for and stores a candidate base station whose reception level is equal to or higher than a holding level, or holds the reception state in the background monitor, and further receives a control channel of the base station. When the level falls below the holding level,
A portable terminal comprising means for switching the base station to the candidate base station.