JP2000115355A - Cordless telephone set - Google Patents

Abstract

PROBLEM TO BE SOLVED: To establish radio communication with high quality at high speed by avoiding a speech channel, where disturbance or the like may take place in a cordless telephone set consisting of a master set and a slave set in radio connection to this master set. SOLUTION: A channel group in which three consecutive idle channels are in existence is detected (S2, S5), and the channel group is stored in a memory (S3, S6). When a call is sent/received, a middle channel in the three consecutive channels stored in the memory is selected, and the selected channel is used for a speech channel to send/receive a voice signal. Thus, occurrence of disturbing states such as crosstalk is suppressed. Furthermore, idle channels are discriminated in advance, prior to the transmission/reception of a call to set up a radio connection state between a master set and a slave set at high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cordless telephone comprising a master unit and a slave unit, and more particularly to a technique for preventing interference between the master unit and the slave unit.

[0002]

2. Description of the Related Art Conventionally, a cordless telephone has been known in which a base unit and a base unit are wirelessly connected to each other so that the base unit can be freely carried and used within a certain area. This type of cordless telephone is widely used in ordinary homes, offices, and the like because of its advantages that it is not necessary to route telephone lines and that it can be placed anywhere. In such a cordless telephone, a multiple access (multiple access) method in which a plurality of telephones share and use a plurality of channels prepared in the same frequency band is adopted.
The frequency is used effectively. Here, the operation of the conventional cordless telephone at the time of outgoing / incoming call will be described with reference to FIG. The cordless telephone 1 generally has a 250 MH
Frequency bands of the z band and the 380 MHz band are allocated, and transmission / reception operations are performed between the master unit 3 and the slave unit 4 using these frequency bands. This frequency band is divided into 89, two of which (46, 89 channels) are used as control channels, and the remaining 87 channels are used as communication channels. It should be noted that one identification code (ID) is assigned to each of the parent device 3 and the child device 4 of the cordless telephone 1 for each set. The wireless connection is established only between the handset 3 and the handset 4.

The master unit 3 detects an idle channel from the communication channels during standby and stores this channel number. Then, when there is a call request from the handset 4 via the control channel, the availability of the call channel detected during standby is checked again, and if this call channel is unused, the handset 4 is Then, an instruction for transmitting and receiving the audio signal using this channel is given using the control channel. Further, if the call channel that has been found is in use, the operation of detecting an empty channel is performed again.
, An instruction to transmit and receive an audio signal using the communication channel is given using the control channel. Next, the wireless connection between the parent device 3 and the child device 4 is completed by switching to the same communication channel. It should be noted that, also when an incoming call request is issued from the telephone line 2 to the base unit 3, an instruction of a communication channel is given from the base unit 3 to the slave unit 4 as described above.

In such a cordless telephone, various devices have been devised for quickly establishing a wireless connection state between a master unit and a slave unit.
Japanese Patent Application Laid-Open No. 2001123 discloses that when a power supply is turned on, an idle channel is detected, and immediately after the detection, the communication channel is notified to the child device and set as an initial communication channel, thereby making a call from the child device. A cordless telephone is shown that can quickly establish a wireless connection between a master unit and a slave unit when a request is made. Furthermore, for example, in Japanese Patent Application Laid-Open No. Hei 7-222233, the communication channel used in the previous call is stored, and this communication channel is preferentially selected, so that the operation of selecting the communication channel can be speeded up. The illustrated cordless telephone is shown.

[0005]

However, in the above-mentioned conventional cordless telephone, the empty state of the communication channel is individually detected, and the empty channel is used as a channel for transmitting and receiving voice signals. If a channel adjacent to the detected channel is in use, there is a problem that signals of the two channels are mixed and interference such as interference may occur.
Such inconvenience tends to occur particularly when the slave unit 4 is used while being moved.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and provides a cordless telephone which can establish a high-quality wireless communication at a high speed while avoiding a communication channel which may cause interference or the like. The purpose is to:

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a cordless telephone comprising a base unit connected to a telephone line and a base unit wirelessly connected to the base unit. And / or the slave unit transmits and receives a control signal between the master unit and the slave unit using a predetermined control channel, and transmits and receives a voice signal using a predetermined communication channel. An empty channel detecting unit for detecting a channel group in which two or more channels are empty channels; and a storage unit for storing the empty channel group detected by the empty channel detecting unit. One of the channels stored in the storage means is selectively used as a communication channel.

In this configuration, at power-on or at any time, a channel group in which at least two or more continuous channels are empty channels is detected, and the channel group is stored in the storage means. Then, when performing the outgoing / incoming / receiving operation, one channel is selected from the channels stored in the storage means, and the transmitting / receiving operation of the audio signal is performed using this channel as a communication channel. In this way, by setting one of at least two or more continuous idle channels as a communication channel at the time of transmission / reception operation, occurrence of an interference state such as interference that may occur because an adjacent channel is in use. Can be suppressed. In addition, by performing an operation of determining an empty channel in advance before an outgoing / incoming call operation, it is possible to quickly establish a wireless connection state between the master unit and the slave unit.

Further, the above-mentioned empty channel detecting means,
A plurality of channel groups in which at least two or more channels are continuously empty channels may be detected, and the plurality of channel groups may be stored in the storage unit. In this configuration, by preliminarily storing a plurality of channel groups, even if one channel group is in use, it is possible to quickly shift to another channel group.

Preferably, the transmission / reception means selects and uses a middle channel of one channel group stored in the storage means at the time of transmission / reception as a communication channel at the time of transmission / reception. In this configuration, the channel adjacent to the channel selected as the communication channel at the time of transmission / reception can be set as the idle channel, so that the occurrence of an interference state such as interference can be reliably prevented.

The transmission / reception means selects one channel group from the channel groups stored in the storage means at the time of transmission / reception, checks the availability of the channel group, and checks all the channels of this channel group. If is not available, one of the channel groups is selected and used as a communication channel. If even one of the channels is not empty, another channel group is selected from the storage means. The availability of the channel group may be checked, and the same processing may be performed thereafter.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a cordless telephone according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a processing system of a cordless telephone according to the present invention. The cordless telephone 1 includes a base unit 3 connected to an external office line such as a telephone line 2 and a slave unit 4 wirelessly connected to the base unit 3. The transmission / reception operation between the master unit 3 and the slave unit 4 is performed by using this. Also, in the cordless telephone 1, the frequency band allocated for the cordless telephone is divided into 89 channels in the same manner as that shown in FIG.
89 channels are used as control channels for transmitting and receiving control signals, and the remaining 87 channels are used as communication channels for transmitting and receiving voice signals.

A central processing unit (hereinafter referred to as a CP) for controlling the master unit 3
U) 10 includes a microphone 11 that captures an audio signal (user's voice) and converts the audio signal into an electric signal, a speaker 12 that converts the voice of the other party transmitted as the electric signal into an audio signal, An operation key 13 including a dial numeric keypad and a redial key, a memory 14 (storage means) for storing various data such as speed dial numbers, and a display unit 15 for displaying various messages are connected. Further, when receiving a calling signal from the telephone line 2, the CPU 10 has a ring tone generating circuit 16 for generating a ring tone in response to the calling signal, and a line control circuit 17 for controlling connection and disconnection of the line with the telephone line 2. And are connected. In addition, parent machine 3
Is a transmitting unit 18 for transmitting a control signal and an audio signal to the slave unit 4, a high-frequency receiving unit 19 for receiving the control signal and the audio signal transmitted from the slave unit 4, and a PLL for demodulating the received signal. (Phase-locked loop) 20 and an empty channel determination circuit 21 (empty channel detection means) for determining an empty channel. The transmission unit 18, the high-frequency reception unit 19, and the PLL 20 constitute transmission / reception means of the present invention.

The central processing unit 30 for controlling the slave unit 4 includes a microphone 31 for converting an audio signal into an electric signal, a speaker 32 for converting the voice of the other party into an audio signal, a ten-key pad for a dial and a redial key. The operation key 33 is connected to a ring tone generation circuit 36 that generates a ring tone in response to a control signal from the base unit 3. The child device 4 is the parent device 3
Transmitting a control signal and an audio signal toward
And a high-frequency receiving unit 39 that receives the control signal and the audio signal transmitted from the base unit 3, and a P that demodulates the received signal.
LL40. The transmitting section 38, the high-frequency receiving section 39, and the PLL 40 constitute a transmitting / receiving section of the present invention.

Next, the operation of detecting an empty channel by the cordless telephone 1 will be described with reference to the flowchart of FIG. This idle channel detection operation is performed when the power of the telephone 1 is turned on or in a standby state.
Is performed as needed. First, the CPU of master unit 3
10 drives the PLL 20 to change the receivable frequency band, and performs empty detection for up to 88 communication channels excluding 46 control channels in order from 1 channel (S1). This empty channel determination operation is performed by checking the signal level received for each channel by the empty channel determination circuit 21.
If the level is equal to or less than the reference value, the process is performed by setting an empty channel. Here, when it is determined that three channels are empty channels consecutively (YES in S2), a channel group including these three channels is determined as an empty block 1 (S3), and this empty block 1 is stored in the memory 14 To memorize. Subsequently, the same empty channel detection operation as described above is performed (S4, S5). If three channels are continuously empty channels (YES in S5), this channel group is determined as an empty block 2 (S6). The empty block 2 is stored in the memory 14, and the operation of detecting the empty channel ends. The above-described empty channel detection operation is continued until three consecutive channels are determined to be empty channels (NO in S2 and S5). In addition, empty block 1
And the channel selected as the empty block 2 are different from each other.

Next, the wireless connection operation between the base unit 3 and the slave unit 4 at the time of an incoming call will be described with reference to the flowchart of FIG. When receiving the call signal from the telephone line 2, the CPU 10 of the base unit 3 starts an incoming call confirming operation for checking whether or not the call signal is genuine (S10).
11) When the incoming call confirmation operation is completed, the transmitting unit 18 is driven to transmit a connection request signal to the slave unit 4 using the control channel (S12). When the acknowledgment signal ACK is received from the slave unit 4 in response to the connection request signal (S13), the channel group of the empty block 1 detected as an empty channel by the empty channel detection operation shown in FIG. 14 and detects the empty state of these channel groups (S14). Here, when all the channels of this channel group are free (NO in S14), the middle channel of the channel group is selected as a communication channel (S15). That is,
For example, when channels 6, 7, and 8 are stored in the memory 14 as empty blocks 1, channel 7 is selected as a communication channel. Subsequently, the selected communication channel is notified to the slave unit 4 using the control channel, and the master unit 3 and the slave unit 4 are shifted to the communication channel, so that the master unit 3 and the slave unit 4 Communication between them is established, and the wireless connection is completed.

In S14, if at least one channel of the channel group of the empty block 1 is not empty (YES in S14), the channel group of the empty block 2 is read from the memory 14, and the middle channel of the channel group is read. The communication channel is selected, and communication between the master unit 3 and the slave unit 4 is established using this communication channel (S16).

Next, the wireless connection operation between the master unit 3 and the slave unit 4 at the time of calling will be described with reference to the flowchart of FIG. When a hook switch (not shown) of the handset 4 is operated and a call request signal from the handset 4 is received (2)
1) The master unit 3 performs an empty state detection operation of the channel group of the empty block 1 (S22). The operation after S22 is
The operation is the same as the operation after S14 in FIG. 3 described above. If all the channels of the channel group of the empty block 1 are free (NO in S22), the middle channel of the channel group is selected as the communication channel. The communication between the master unit 3 and the slave unit 4 is connected by using this communication channel. In S22, if at least one channel of the channel group of the empty block 1 is not empty (NO in S22), the channel group of the empty block 2 is read from the memory 14, and the middle channel of the channel group is set as the communication channel. Then, communication is established on the communication channel between the master unit 3 and the slave unit 4 using this communication channel (S24).

As described above, according to the cordless telephone 1 shown in the present embodiment, the channel group determined to be an empty channel for three consecutive channels is stored, and the middle channel of the channel group is used for making and receiving calls. Since the channel is selected, it is possible to establish high-quality communication in which the occurrence of an interference state such as interference that may occur because an adjacent channel is in use is suppressed. In addition, since the operation of determining an empty channel is performed in advance when the power is turned on or during standby, the wireless connection state between the master unit 3 and the slave unit 4 can be quickly established.

Further, by storing the channel groups of a plurality of blocks in the memory 14 in advance, even if one channel group is in use, it is possible to promptly shift to another channel group. Thus, it is possible to more quickly select a communication channel.

The present invention is not limited to the above embodiment, but can be variously modified. For example, in the above embodiment, the empty channel determination circuit 21
Although it is mounted only on the slave unit 4, it may be provided on the slave unit 4. Further, in the above embodiment, the middle channel of the channel group determined as an empty channel for three consecutive channels is selected as a communication channel at the time of transmission / reception, but it is determined that four or more consecutive channels are empty channels. A communication channel for outgoing / incoming calls may be selected from a group of channels. In addition, a channel group determined to be an empty channel for two consecutive channels is stored, and at the time of transmission / reception, the empty state of both adjacent channels is detected, and it is confirmed that the adjacent channel is an empty channel. The selected channel may be selected as a communication channel.

In the above embodiment, two sets of channels (empty blocks 1 and 2) are stored in the memory 14, but three or more sets of channels are stored in the memory 14. You may. Also, remembering the history of the call channels used in the past, when it is determined that all the channels stored in the memory 14 are in use in the operation of determining an empty channel at the time of outgoing / incoming, A connection to the call channel used in the past may be made. Furthermore, in the above-described embodiment, the cordless telephone including one master unit and one slave unit has been described. However, the cordless telephone may include one master unit and a plurality of slave units.

[0023]

As described above, according to the cordless telephone of the present invention, a channel group in which at least two or more continuous channels are empty channels is stored, and one channel of the channel group is transmitted and received. Since the communication channel is selected as a communication channel during operation, it is possible to establish a high-quality communication in which an interference state such as interference that may occur because an adjacent channel is in use is suppressed. Further, since the determination operation of the empty channel is performed before the transmission / reception operation, the wireless connection state between the master unit and the slave unit can be quickly established.

Further, by storing a plurality of groups of channels in advance, even if one channel group is in use, it is possible to quickly shift to another channel group.

Further, by selecting and using the middle channel of the channel group as a communication channel at the time of transmission / reception, it is possible to reliably prevent the occurrence of interference such as interference.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a processing system of a parent device and a child device constituting a cordless telephone according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining an empty channel detection operation.

FIG. 3 is a flowchart for describing a wireless connection operation between a master unit and a slave unit at the time of an incoming call;

FIG. 4 is a flowchart for explaining a wireless connection operation between the master unit and the slave unit at the time of calling.

FIG. 5 is a diagram for explaining a mechanism of the present invention and a conventional cordless telephone.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cordless telephone 2 Telephone line 3 Base unit 4 Remote unit 14 Memory (storage means) 18 Transmitter (transmitter / receiver) 19 High-frequency receiver (transmitter / receiver) 20 PLL (transmitter / receiver) 21 Empty channel determination circuit (empty channel detector)

Claims (4)

[Claims] 1. A cordless telephone comprising a master unit connected to a telephone line and a slave unit wirelessly connected to the master unit, wherein the master unit and / or the slave unit are connected between the master unit and the slave unit. Transmission / reception means for transmitting / receiving a control signal using a predetermined control channel and transmitting / receiving a voice signal using a predetermined communication channel, and a channel group in which at least two or more continuous channels are empty channels Vacant channel detecting means for detecting a vacant channel group detected by the vacant channel detecting means, and a storing means for storing a vacant channel group detected by the vacant channel detecting means. A cordless telephone characterized by selecting and using one channel from among: 2. A plurality of channel groups in which at least two or more channels are continuously empty channels are detected by the empty channel detecting means, and the plurality of channel groups are stored in the storage means. The cordless telephone according to claim 1, wherein 3. The transmission / reception unit according to claim 1, wherein, at the time of outgoing / incoming call, a middle channel of one channel group stored in the storage unit is selected and used as a communication channel at the time of outgoing / incoming call. Cordless telephone. 4. The transmission / reception means selects one channel group from a group of channels stored in the storage means at the time of outgoing / incoming call, checks the availability of the channel group, and checks all the channels of this channel group. If a channel is vacant, one of the channel groups is selected and used as a communication channel. If at least one of the channels is not empty, another channel group is stored in the storage means. The cordless telephone according to any one of claims 1 to 3, wherein the cordless telephone is selected, a vacant state of the channel group is checked, and the same processing is performed thereafter.