JPH10215484A - Digital cordless telephone system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain the mode switching between the private and public systems with no omission of detection of an incoming signal by retrieving the signal of the other telephone system to switch the working telephone system to the other one in response to the incoming state of the other system during the incoming timing of intermittent reception set in the current reception mode. SOLUTION: In an incoming waiting state where the intermittent reception is performed in response to the transmission timing of a base station, a retrieval changeover switch 17 sends the reception output of a radio part 11 to an incoming detection part 18. When a service area is moved to a public system from a private system and a reception quality decision part 20 detects the deterioration of reception quality, the switch 17 is switched to a retrieval mode 15 to retrieve the signal of the public system in a term untill the next reception timing is set right after the current reception timing. If the reception quality of the public system is satisfactory, a reception mode changeover switch 16 is switched to a public reception mode 14 to wait the incoming call.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital cordless telephone apparatus, and more particularly to a digital cordless telephone apparatus which receives signals intermittently transmitted at different timings and different frequencies from base stations of a private telephone system and a public telephone system (for example, PHS). The present invention relates to a digital cordless telephone device that can be used.

[0002]

2. Description of the Related Art A digital cordless telephone of this type is provided within a service area of a base unit of a private telephone system.
In a reception mode in which an incoming signal from the base unit can be received and wait for an incoming call. When the mobile terminal moves into the service area of the public telephone system, the reception mode in which the incoming signal from the base station of the public telephone system can be received and the incoming call is received. Like that.

[0003] For example, according to Japanese Patent Application Laid-Open No. 7-087565, when it becomes impossible to read the call code of the private system while operating in the reception mode of the private system, automatic operation is performed after a specified time has elapsed. The mode is switched to the public system reception mode. According to Japanese Patent Application Laid-Open No. H08-079829, when a power supply is turned on or when an out-of-service area is detected, a signal from a public base station and a signal from a private base station are received and communication is possible. If there is a self-owned base station, set it to the reception mode of the self-operated system.If communication with the self-operated base station is not possible and communication with the public base station is possible, set it to the reception mode of the public system. You have set.

[0004]

However, in the former case of the above-mentioned conventional example, after the calling code of the private system cannot be read out, the mode is switched to the receiving mode of the public system after a lapse of a specified time. Missing detection of an incoming signal from the base station occurs. Further, in the latter, the relationship between the reception timing and the search timing when searching for signals from the private base station and the public base station is not specified, and there is a possibility that missed detection of an incoming signal may occur.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a digital communication system capable of switching a reception mode between a private system and a public system without being affected by the frequency and timing of the private system and the public system and without failing to detect an incoming signal. A cordless telephone device is provided.

[0006]

According to the digital cordless telephone apparatus of the present invention, the signal search of the other telephone system for switching the reception mode is performed until the next reception timing arrives from the reception timing in the current reception mode. Run within the period. When switching to the reception mode of the other telephone system, the switching is performed within a period from the reception timing of the other telephone system to the next reception timing.

Specifically, a self-service reception mode for intermittently receiving a signal intermittently transmitted at a predetermined timing from a base station of a private telephone system, and a signal intermittently transmitted at a predetermined timing from a base station of a public telephone system. Public reception mode for intermittent reception, means for determining the quality of reception quality in the current reception mode, means for searching for a signal of the other telephone system when reception quality deteriorates, and search for a signal of the other telephone system Means for switching to the reception mode of the other telephone system in accordance with the result and the reception quality, wherein the signal search means searches for a signal of the other telephone system within a period other than the reception timing in the current reception mode. The receiving mode switching means switches the receiving mode within a period other than the signal reception timing of the other telephone system.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 4 is a diagram showing a configuration example of a digital cordless telephone system, in which a digital cordless telephone device 1 moves from a service area of a base station 2 of a private system to a service area of a base station 3 of a public system. Thus, the case where the service areas of both systems are located in the overlapping area 4 is shown.

When the digital cordless telephone device 1 is within the service area of the base station 2 of the self-operating system, the digital cordless telephone device 1 enters a reception mode for receiving an incoming signal from the base station 2 and waits for an incoming call. When the mobile station moves to the service area of the base station 3 of the public system, the mobile station automatically switches to a reception mode in which an incoming signal from the base station 3 can be received and waits for an incoming call. The switching of the reception mode is performed in the area 4.

As shown in FIG. 3A, incoming signals transmitted from the base stations of the private and public systems have different frequencies f1 and f2 and different timings (periods T1 and T1).
Each is intermittently transmitted at T2). The periods T1 and T2 are about 1 second. The digital cordless telephone device 1
Intermittent reception is performed according to the transmission timing of the self-employed / public system to wait for an incoming call while suppressing battery consumption.

FIG. 1 is a block diagram showing an embodiment of the present invention.

The radio unit 11 is controlled by the reception control unit 12 so as to intermittently receive signals from base stations of the private telephone system and the public telephone system. Private reception mode 1
Reference numeral 3 denotes a reception mode in which intermittent reception is performed in accordance with the transmission timing of an incoming signal intermittently transmitted from the base station of the private system. The public reception mode 14 is a reception mode in which intermittent reception is performed according to the transmission timing of an incoming signal intermittently transmitted from a base station of a public system. The reception mode changeover switch 16 is controlled by the reception control unit 12 to select one of the self-service and public reception modes 13 and 14.

The search mode 15 is a mode for performing a signal search of the other telephone system in advance when switching the reception mode. For example, if the reception operation is performed in the private reception mode, the reception frequency is set to a signal from the base station of the public telephone system. Search switch 17
Is controlled by the reception control unit 12 to select one of the reception mode and the search mode 15, and at the same time, changes the reception output of the radio unit 11 to the reception
9 is supplied. Here, search mode 15
When is selected, the reception output of the radio unit 11 is supplied to the signal search unit 19, and when the reception mode is selected, the reception output of the radio unit 11 is supplied to the incoming call detection unit 18. The signal search unit 19 detects the reception timing of the reception signal and notifies the reception control unit 12 of the detection timing.

The reception quality judgment section 20 detects the reception level of the reception signal, and judges the quality of the reception quality based on the average value. By determining the average value in this way, erroneous determination due to fading or the like can be reduced.

Next, the operation of the reception control unit 12 will be described with reference to FIGS. Here, it is assumed that the digital cordless telephone device is moving from the service area of the private system to the service area of the public system, and is operating in the private reception mode.

FIG. 2 is a flowchart showing the operation of the reception control unit 12. FIG. 3 is a timing chart showing the operation of the reception control unit 12. As shown in FIG. 3B, the digital cordless telephone apparatus performs intermittent reception in the reception mode of the private system and waits for an incoming call (step 1).
01). When the reception quality judgment unit 20 judges that the reception quality has deteriorated (step 102), as shown in FIG.
During the period from immediately after the reception timing of the self-employed system until the next reception timing arrives, the search changeover switch 17
To select a search mode, and
Is supplied to the signal search unit 19, and the signal search of the public system is executed (step 103). Then, the reception quality of the public system is compared with the reception quality of the private system. If the reception quality of the public system is better (step 104), the reception mode switch 16 is caused to select the private reception mode. (Step 105).

The digital cordless telephone device is
When moving from the service area of the public system to the service area of the self-employed system, the same operation is performed by replacing “self-employed” with “public”.

[0019]

As described above, according to the present invention, the signal search of the other telephone system for switching the reception mode is performed during the period from the reception timing in the current reception mode until the next reception timing arrives. Since the current reception is not affected, the reception mode between the private system and the public system can be switched without causing missed detection of the incoming signal.

Further, when switching to the reception mode of the other telephone system, switching is performed within a period from the reception timing of the other telephone system to the next reception timing, so that the missed detection of the incoming signal of the other telephone system is prevented. Can be avoided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of a reception control unit 12 shown in FIG.

FIG. 3 is a timing chart showing an operation of the reception control unit 12;

FIG. 4 is a diagram showing a configuration example of a digital cordless telephone system.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 Radio part 12 Reception control part 13 Private reception mode 14 Public reception mode 15 Search mode 16 Reception mode changeover switch 17 Search changeover switch 19 Signal search part 20 Reception quality judgment part 101-105 Steps showing operation of reception control part 12

Claims (4)

[Claims] 1. A digital cordless telephone device for selecting one of base stations that intermittently transmit an incoming signal at a different timing for each base station and switching to a reception mode for intermittently receiving the incoming signal in accordance with the timing. A digital cordless telephone device wherein signal search and reception mode switching are performed using a period other than the reception timing of an incoming signal. 2. A digital cordless telephone device which can be shared by both a private telephone system and a public telephone system, wherein the private reception mode intermittently receives a signal intermittently transmitted at a predetermined timing from a base station of the private telephone system. And a public reception mode for intermittently receiving a signal intermittently transmitted at a predetermined timing from a base station of the public telephone system, and means for determining whether reception quality is good or bad in the current reception mode. Means for searching for a signal of the other telephone system, and means for switching to a reception mode of the other telephone system according to the search result and reception quality of the signal of the other telephone system,
The digital cordless telephone device according to claim 1, wherein said signal search means performs a signal search of said other telephone system during a period other than the reception timing in said current reception mode. 3. The reception mode switching means, wherein when the reception quality of the signal of the other telephone system is better than the reception quality in the current reception mode, the signal of the other telephone system is changed. 3. The digital cordless telephone device according to claim 2, wherein the reception mode is switched during a period other than the reception timing. 4. The digital cordless telephone device according to claim 2, wherein said reception quality determination means makes a determination based on an average value of reception levels.