JPH0712232B2 - Cordless telephone system - Google Patents

Description

The present invention relates to a cordless telephone system used on a premises or indoors. In particular, it relates to a method of detecting and notifying a reception level from a cordless wireless telephone to a fixed device.

[Conventional technology]

There are two types of cordless telephone systems. One is a so-called low power type, which is a type in which a fixed device assigns a free telephone channel to a wireless telephone every time a call connection is made by using a multi-channel access technology. The other is a type that uses arbitrary weak radio waves.

Also, recently, a parent-child cordless phone capable of connecting a plurality of wireless phones to one fixed device has been developed, and a plurality of fixed devices are arranged in a plurality of spaces so that a plurality of wireless phones can talk to any fixed device. A multi-zone cordless telephone system that can be connected has also been proposed.

What these cordless telephone systems have in common is that carrier sensing must be performed first before a call to confirm that the channel is empty and to transmit the necessary signal. That is, the fixed device of the cordless telephone and the wireless telephone need to be provided with a reception level discriminating circuit (so-called squelch circuit) for discriminating whether the signal level is above or below a certain value. In addition, in the multi-zone cordless telephone system, for example, a fixed device needs to detect the reception level of a signal from the wireless telephone in order to select the nearest wireless zone where the wireless telephone exists. This is because when multiple fixed devices receive signals from the same wireless telephone, the zone with the highest reception level is selected, and unless the wireless telephone moves to another zone, the fixed device with which the call is selected is selected. This is because it is done between.

Another common point of the cordless telephone system is that two-way communication must be possible at the same time in order to maintain the function as a telephone.

That is, one speech channel is composed of two frequencies, and the frequency from the fixed device to the wireless telephone (downline) and the frequency from the wireless telephone to the fixed device (uplink) are different.

As described above, in the cordless telephone system, the fixed device and the wireless telephone monitor the reception level of the line of the frequency transmitted by the other party to grasp the state of the channel to be used.

[Problems to be solved by the invention]

However, in the cordless telephone system, since the frequencies of the uplink and downlink lines are different (especially in the low power type, they are set to be separated by 100 MHz or more.) The reception level may differ significantly from that of a telephone. Further, since the fixed device and the wireless telephone have different shapes, effective radiated power is different.

For this reason, the phenomenon in which the uplink and downlink lines are not always equal may occur, but since the fixed device and the wireless telephone do not have means for grasping the line state received by the other party, the channel state can be accurately determined. It was difficult to grasp and perform wireless transmission.

This is a factor that reduces the accuracy of zone selection, especially in the multi-zone cordless telephone system in which the nearest wireless zone is selected depending on the reception level, and an inappropriate zone may be selected.

The object of the present invention is to solve the above-mentioned problems and to be used as an electric field measuring device by detecting the reception level of a signal transmitted by a wireless telephone to a fixed device and notifying the level to the wireless telephone. , To recognize its own wireless zone range and to improve the accuracy of zone selection in the multi-zone cordless telephone system.

[Means for solving problems]

The present invention includes a plurality of fixed devices and at least one wireless telephone, and selects one of the multi-zones formed by the plurality of fixed devices so that the wireless telephone establishes a wireless line with one fixed device. In the cordless telephone system for forming and performing wireless communication, the fixed device includes means for detecting a reception level of a signal from the wireless telephone, and means for notifying the wireless telephone of the detected reception level. The telephone is characterized by including means for selecting a fixed device to be connected by a wireless line based on a reception level from the wireless telephone and a reception level of a signal from the fixed device notified from the fixed device.

[Action]

When the fixed device receives a call signal or an incoming signal from the wireless telephone, it detects the received level, encodes the received level or its representative value, inserts it into the control signal, and sends it to the wireless telephone. Notice.

The wireless telephone receives the notification of the reception level or its representative value from the fixed device, displays it on the display device, or uses it to select the position registration for a plurality of fixed devices and uses it for position registration notification and other purposes.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram for explaining a cordless telephone system according to an embodiment of the present invention. In the cordless telephone system of the present embodiment, the fixed device 1 and the wireless telephone 2 can set a call channel via the wireless line 3 to make a call, and the fixed device 1
It is connected to a fixed telephone network 5 via an external line 4. The system composed of the fixed device 1 and the wireless telephone 2 is the minimum configuration of the cordless telephone system.

FIG. 2 is a diagram showing the configuration of the fixing device 1 of this embodiment.

The fixing device 1 is roughly configured to include a radio unit and a baseband unit. The baseband unit is connected to the two-wire to four-wire conversion circuit 11 connected to the external line 4, the baseband circuit 12 that performs baseband signal processing, the control circuit 15 that controls the overall operation, and this control circuit 15. And a memory circuit 16. The radio section is a baseband circuit
It is composed of a transmitter 13 for transmitting a signal from 12, a receiver 14 for receiving a signal from a wireless telephone, and an antenna duplexer 17 for sharing the antenna 18 with the transmitter 13 and the receiver 14. In addition to the configurations of the baseband unit and the radio unit, the fixing device 1 of the present embodiment includes a squelch circuit 19 that is connected to the receiver 14 and the control circuit 15 and detects whether or not a channel is vacant, and the receiver 14 as well. And a reception level detection circuit 20 connected to the control circuit 15 for detecting the reception level from the wireless telephone.

FIG. 3 shows the configuration of the wireless telephone 2 of this embodiment. The configuration of the wireless telephone 2 is almost the same as the configuration of the fixed device 1, and includes an antenna duplexer 21 connected to the antenna 34, a transmitter 22 and a receiver 23 connected to the antenna duplexer 21, This transmitter 22 and receiver
23 is connected to the baseband circuit 24, the baseband circuit
24 and these transmitters 22 and receivers 23 are connected to a control circuit 27 that controls the entire wireless telephone. Also, the receiver 23
, A squelch circuit 25 that detects whether the channel is empty,
A reception level detection circuit 26 for detecting the reception level from the fixed device 1 is connected, and both circuits are connected to the control circuit 27 described above. Further, a memory circuit 28 is connected to the control circuit 27. In addition, the baseband circuit 24 is the receiver 29
And a microphone 30 are connected, and a dial key 31, a display 32, and a sounder 33 are connected to the control circuit 25.

FIG. 4 shows the most general calling and receiving sequences in the cordless telephone system composed of the fixed device 1 and the wireless telephone 2 of this embodiment.

In FIG. 4, reference numeral 41 corresponds to the wireless telephone 2 of FIG. 1, and reference numeral 42 corresponds to the fixed device 1.

FIG. 4 (a) shows call control from the wireless telephone, in which the call signal (1a) from the wireless telephone 41 is sent to the fixed device 42.
When the call is received at, the call response signal (1b) is transmitted to the wireless telephone 41 to confirm the call connection. At this time, the reception level detection circuit 20 detects the reception level from the wireless telephone 41, the representative value is encoded through the control circuit 15, and the call response signal (1b) is used as the reception level signal (1c) in the wireless telephone 41. To notify.

FIG. 4B shows the incoming call control from the fixed device. The fixed device 42 sends an incoming call signal (1d) to the wireless telephone 41, and the incoming call response signal (1e) from the wireless telephone 41. Received,
Send the call channel specification signal (1f). In this case, the fixed device 42 detects the reception level of the incoming call response signal (1e) and notifies the radio telephone 41 of the reception level signal (1c) by the call channel designation signal (1f).

The reception level detected by the reception level detection circuit 20 of the fixed device 42 and notified to the wireless telephone 41 may be a representative value of the detected levels, and may be, for example, an ensemble average value, a median value, or a sampling value at that time. Good.
Here, the median means the 50% value of the distribution of fluctuations in the reception level.

Although there is no particular limitation on how to display or encode the representative value of the reception level in the present embodiment, the control signal from the fixed device 42 is added with a bit indicating the representative value of the reception level to notify the control signal, and the wireless telephone Considering display, encoding of about 3 bits is sufficient.

An example of such 3-bit encoding is given below as a table.

In the example of the table, the value of the received electric field strength is divided from 10 dBμ to 50 dBμ at 10 dB intervals, and the representative value of the reception level is set to one of the values. Such level of detection methods are quite common and well known.

Thus, the reception level signal (1c) notified from the fixed device 42 is temporarily stored in the memory circuit 28 of the wireless telephone 41. The reception level stored or stored in the memory circuit 28 can be referred to or displayed by, for example, a user of the wireless telephone 41 operating the key 31 to select the level display mode.
A method of reading out and displaying from the memory circuit 28 together with the downlink reception level detected by the reception level detection circuit 26 of the wireless telephone 41 can be considered as 32. Further, when the reception level detected by the fixing device 42 is lower than the required level, the sounder 33 can issue an alarm. As a result, the wireless telephone can be used as a simple electric field measuring device and can be used for recognizing the effective wireless zone area range.

Next, another embodiment in the case of implementing the multi-zone cordless telephone system will be described.

FIG. 5 is a diagram for explaining a multi-zone cordless telephone system. In the multi-zone cordless telephone system, a line controller 51 and a plurality of fixed devices 52, 53, 54, 55 connected to the line controller 51 are used. The fixed devices 52 to 55 are composed of a plurality of wireless telephones 56-1 and 56-2 in a wireless zone.

Even in this multi-zone cordless telephone system, it is of course possible to display the reception level information notified to the wireless telephone 56 shown above from the fixed device on the display unit 32 as needed.

An example of applying the reception level notification from the fixed devices 53 to 55 to the position registration of the wireless telephone 56 in the multi-zone cordless telephone system shown in FIG. 5 will be described with reference to FIGS. 6 to 7.

The location registration method itself in the multi-zone cordless telephone system is a well-known technique, and a location registration request signal that designates a fixed device as a non-designation is transmitted from a wireless telephone, and each fixed device that receives this location registration request signal is a wireless telephone. The response is sent back to the wireless telephone, and the wireless telephone selects the nearest fixed device from the received responses. At this time, for example, the timing of transmitting the response is controlled according to the reception level of the position registration request signal from the wireless telephone so that the response from the fixed device does not interfere.

FIG. 6A shows reception when one of the wireless telephones 56, for example, the wireless telephone 56-1 transmits a position registration request signal and the registration request signal is received by each of the fixed devices 53 to 55. The level is shown in FIG. 6 (b), and the level received by the wireless telephone 56-1 of the response signal returned by the fixed devices 53, 54, 55 is shown on the time axis. Here, FIG. 6 (a)
The level 57 indicates the reception level of the position registration signal detected by the fixed device 53, the level 58 indicates the reception level detected by the fixed device 55, and the level 59 indicates the reception level detected by the fixed device 54. Further, the level 60 in FIG. 6 (b) is a fixing device.
The response signal from 53 is the reception level of the response signal detected by the wireless telephone 56-1, level 61 is the level of the response signal transmitted from the fixed device 54, and level 62 is the response transmitted from the fixed device 55. Represents the signal level respectively.

FIG. 7 shows a sequence of position registration of the wireless telephone 56.

The wireless telephone 56-1 transmits a position registration request signal (2a) to the fixed devices 53 to 55, and each fixed device 53, 54, 55 receives the position registration request signal and detects its reception level. Then, the detected reception level is changed to the response signals (2b), (2c), (2d) according to the timing determined by the fixed device.
Is sent back, and the detection reception level at each fixed device is encoded in the response signal and transmitted.

The wireless telephone 56-1 has a representative value of the reception level of the response signal from the fixed devices 53 to 55 on the uplink and the reception level of the response signal detected by the reception level detection circuit 26 of its own device, that is, the reception level of the downlink. The fixed device having the largest value obtained by adding the representative value of is selected as the nearest fixed device.

In the example shown in FIG. 7, the fixing device 54 is selected as the nearest fixing device. This is the down level, fixed device
Although the fixing device 55 is larger than the fixing device 54 (level 61 <level 62 in FIG. 6 (b)), the level of the ascending device 54 is higher.
Is larger than the fixing device 55 (Fig. 6 (a)).
This is because the fixed device 54 is selected at level 59> level 58). Then, the wireless telephone 56-1 transmits a position registration notification signal (2e) to the fixed device 54, and returns a response signal (2f) from the fixed device 54 so that the position registration of the wireless telephone 56-1 is completed. finish.

〔The invention's effect〕

As described above, according to the present invention, the fixed device detects the uplink reception level from the wireless telephone and notifies the wireless telephone. Therefore, first, in the general cordless telephone system and the multi-zone cordless telephone system. ,
By displaying the reception level notified from the fixed device on the wireless telephone, it can be used as a simple electric field measuring device. Especially when a plurality of fixed devices are arranged as in the multi-zone cordless telephone system, it is convenient for the user to display the reception level when estimating the wireless zone area.

In addition, when using the location registration method of a multi-zone cordless telephone type wireless telephone, the optimal wireless zone is selected compared to when the location is registered by selecting the nearest wireless zone only at the down level or the up level. As a result, the accuracy of zone selection is improved and the call quality can be improved.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a cordless telephone system. FIG. 2 is a block diagram showing the configuration of the fixing device according to the embodiment of the present invention. FIG. 3 is a block diagram showing the configuration of the wireless telephone according to the embodiment of the present invention. FIG. 4 is a basic control sequence diagram of the embodiment. FIG. 5 is a diagram for explaining the configuration of the multi-zone cordless telephone system. FIG. 6 is a diagram showing an example of a reception level detected by a fixed device in a multi-zone cordless telephone system and a reception level of a response signal. FIG. 7 is a diagram showing a location registration sequence in the multi-zone cordless telephone system. 1, 42, 52 to 55 ... Fixing device, 2, 41, 56-1, 56-2
...... Wireless telephone, 3 …… Wireless line, 4 …… External line, 5
...... Fixed communication network, 11 ...... 2-wire to 4-wire conversion circuit, 12, 24 ......
Baseband circuit, 13, 22 ... Transmitter, 14, 23 ... Receiver, 15, 27 ... Control circuit, 16, 28 ... Memory circuit, 17,
21 …… antenna duplexer, 18, 34 …… antenna, 19, 25…
… Squelch circuit, 20, 26… Reception level detection circuit, 29…
… Handset, 30 …… Microphone, 31 …… Dial key, 32 ……
Display, 33 …… Sounder, 51 …… Line control device.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location 7304-5K H04B 7/26 109 D

Claims (1)

[Claims] 1. A plurality of fixed devices and at least one wireless telephone, wherein one of the multi-zones formed by the plurality of fixed devices is selected to allow the wireless telephone to connect to one fixed device. In the cordless telephone system for performing wireless communication by forming the above, the fixed device includes means for detecting a reception level of a signal from the radio telephone, and means for notifying the radio telephone of the detected reception level. The wireless telephone is provided with a means for selecting a fixed device to be connected by a wireless line based on a reception level from the wireless telephone notified from the fixed device and a reception level of a signal from the fixed device. Telephone method.