JPH0239738A - Cordless telephone system - Google Patents

Abstract

PURPOSE:To improve the accuracy of a zone selection in a multi-zone cordless telephone system by detecting a receiving level, encoding it, inserting it into a control signal and informing a radio telephone set when an outgoing call signal or an incoming call signal from the radio telephone set is received. CONSTITUTION:When an outgoing call signal from a radio telephone set is received by a fixing device, an outgoing call response signal is transmitted to the radio receiver and the connection of the calling is confirmed. At this time, by a receiving level detecting circuit 20, the receiving level from the radio telephone set is detected, the representative value is encoded through a control circuit 15, and informed the radio telephone set as a receiving level signal with a calling response signal. Thus, the radio telephone set can be used as a simplified electric field measuring device and can be used in order to recognize the area range of an effective radio zone.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cordless telephone system used within a premises or indoors. In particular, the present invention relates to a method for detecting and notifying the reception level from a cordless wireless telephone to a fixed device.

[Conventional technology]

There are two types of cordless telephone systems.

One is the so-called low-power type, in which a fixed device uses multi-channel access technology to assign an empty communication channel to a wireless telephone each time a call is connected. The other type uses arbitrary weak radio waves.

Recently, parent-child type cordless telephones have been developed that allow multiple wireless telephones to be connected to one fixed device. Multiple fixed devices can be placed in multiple spaces, and multiple wireless telephones can communicate with any fixed device. A multi-zone cordless phone system that allows connectivity has also been proposed.

What these cordless telephone systems have in common is that, prior to making a call, carrier sensing must be performed to confirm that the channel is free before transmitting the necessary signals. That is, fixed equipment and wireless telephones for cordless telephones must be equipped with a reception level determination circuit (so-called squelch circuit) for determining whether the signal level is above or below a certain value. Furthermore, in the multi-zone cordless telephone system, in order to select the nearest wireless zone where the wireless telephone exists, the fixed device needs to detect the reception level of the signal from the wireless telephone, for example. This means that when multiple fixed devices receive signals from the same radiotelephone, the zone with the strongest reception is selected and calls are made to the selected fixed device unless the radiotelephone moves to another zone. This is to be done in between.

Another common feature of cordless telephone systems is that they must be able to make two-way calls at the same time in order to retain their telephone functionality.

That is, one communication channel consists of two frequencies, and the line from the fixed device to the wireless telephone (downlink) and the line from the wireless telephone to the fixed device (uplink) use different frequencies.

In this manner, in the cordless telephone system, fixed equipment and wireless telephones each monitor the reception level of the line of the frequency transmitted by the other party, and grasp the state of the channel being used.

[Problem that the invention seeks to solve]

However, in cordless telephone systems, the frequencies of the uplink and downlink lines are different (particularly in low-power models, they are set more than 100 MHz apart), so the propagation characteristics may differ between uplink and downlink, and fixed equipment and wireless The reception level may differ significantly from that of a telephone. Furthermore, since fixed devices and wireless telephones have different shapes, their effective radiated power is different.

For this reason, a phenomenon sometimes occurred where the upstream and downstream line conditions were not necessarily the same, but fixed equipment and wireless telephones do not have a means to grasp the status of the line being received by the other party, so they cannot accurately determine the channel status. It was difficult to understand and perform wireless transmission.

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

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

Means for Solving Problem C] The present invention provides a cordless telephone system in which one fixed device includes at least one wireless telephone, in which the fixed device detects the reception level of a signal from the wireless telephone. and means for notifying the wireless telephone of the detected reception level.

[Effect]

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

The wireless telephone receives a notification of the reception level or its representative value from the fixed device, displays it on a display device, or uses it to select location registration for a plurality of fixed devices, and uses it for location 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 illustrating a cordless telephone system according to an embodiment of the present invention. In the cordless telephone system of this embodiment, the fixed device 1 and the wireless telephone 2 can set up a communication channel via the wireless line 3 and make a call, and the fixed device 1 can
It has a configuration in which it is connected to a fixed line ms via an external line 4. A system consisting of this fixed device 1 and wireless telephone 2 is the minimum configuration of a cordless telephone system.

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

The fixed device 1 is roughly divided into a radio section and a baseband section. The baseband section is connected to a 2-wire/4-wire conversion circuit 11 connected to the external line 4, a baseband circuit 12 that performs baseband signal processing, a control circuit 15 that performs overall operation control, and this control circuit 15. It is composed of a memory circuit 16. The radio section includes a transmitter 13 for transmitting a signal from the baseband circuit 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. It is made up of. In addition to the baseband section and the radio section, the fixed device 1 of the present embodiment includes a squelch circuit 19 connected to the receiver 14 and the control circuit 15 to detect whether a channel is vacant; and a reception level detection circuit 20 connected to the control circuit 15 and detecting the reception level from the wireless telephone.

FIG. 3 shows the configuration of the wireless telephone 2 of this embodiment. The configuration of this wireless telephone 2 is almost the same as that of the fixed device 1, and includes an antenna duplexer 21 connected to an antenna 34, a transmitter 22 and a receiver 23 connected to the antenna duplexer 21, This transmitter 22
and receiver 23 is connected to baseband circuit 24,
Baseband circuit 24 and these transmitters 22 and receivers 2
3 is connected to a control circuit 27 that controls the entire radio telephone. Also, connected to the receiver 23 are a squelch circuit 25 that detects whether a channel is vacant or not, and a reception level detection circuit 26 that detects the reception level from the fixed device 1, and both circuits are connected to the control circuit 27 described above. ing. Further, a memory circuit 28 is connected to the control circuit 27 . The baseband circuit 24 also includes a receiver 29 and a microphone 30.
is connected to the control circuit 25, and the dial key 3 is connected to the control circuit 25.
1, a display 32, and a sounder 33 are connected.

FIG. 4 shows the most common call origination and call reception sequence in the cordless telephone system comprising the fixed device 1 and the wireless telephone 2 of this embodiment.

In FIG. 4, the reference numeral 41 corresponds to the radio telephone 2 in FIG. 1, and the reference numeral 42
corresponds to the fixing device 1.

FIG. 4(a) shows call control from a radio telephone. When the fixed device 42 receives a call signal (1a) from the radio telephone 41, a call response signal (1h) is sent to the radio receiver. 41 to confirm the connection of the call.

At this time, the reception level detection circuit 20 detects the reception level from the radio telephone 41, and its representative value is encoded via the control circuit 15, and the reception level signal (1c) is sent to the radio telephone 41 in the call response signal (1b). Notify.

FIG. 4(b) shows incoming call control from the fixed device, in which an incoming call signal (1d
), and an incoming call response signal (1e
) and transmits a communication channel designation signal (1f).

In this case, the reception level of the incoming call response signal (1e) is detected by the fixed device 42, and the reception level signal (1c) is notified to the radio telephone 41 by the communication channel designation signal (1f).

Detected by the reception level detection circuit 20 of this fixed device 42,
The reception level notified to the radio telephone 41 may be a representative value of the detected level, and may be, for example, an unsampled average value, a median value, or a sampled value at that time. Note that the median value is 5 of the reception level fluctuation distribution.
0% value.

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

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

Table Received level code display example The examples in this table are received electric field strength values from 10 dBμ to 50 dBμ.
The signal up to dBμ is divided into 10 dB increments, and one of the values is taken as the representative value of the reception level. Methods for detecting such levels are very common and well known.

The reception level signal (IC) notified from the fixed device 42 in this manner is temporarily stored in the memory circuit 28 of the wireless telephone 41. The reception level stored in the memory circuit 28 can be referenced or used, for example, by the radio telephone 41.
When the user operates the key 31 to select the level display mode, the level is read out from the memory circuit 28 and displayed on the display 32 together with the downlink reception level detected by the reception level detection circuit 26 of the wireless telephone 41. is possible.

Furthermore, if the reception level detected by the fixed device 42 falls below a required level, the sounder 33 can also issue an alarm. Thereby, the radio telephone can be used as a simple electric field measuring device, and can be used to recognize the area range of a valid radio zone.

Next, another embodiment will be described in which the present invention is applied to a multi-zone cordless telephone system.

FIG. 5 is a diagram explaining the multi-zone cordless telephone system, which consists of a line control device 51 and a plurality of fixed devices 52, 53, 54, 55 connected to this line control device 51. This fixing device 52-5
A plurality of wireless telephones 56 within the wireless zone constituted by
-1.56-2.

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

Examples of applying reception level notifications from the fixed devices 53 to 55 to the location registration of the wireless telephone 56 in the multi-zone cordless telephone system shown in FIG. 5 are shown in FIGS. 6 and 7.
This will be explained with reference to the figures.

The method of location registration in the multi-zone cordless telephone system itself is a well-known technology, in which a wireless telephone transmits a location registration request signal that does not specify any fixed device, and each fixed device that receives this location registration request signal registers as a wireless telephone. The wireless telephone selects the nearest fixed device from among the received responses. At this time,
In order to prevent responses from fixed devices from interfering with each other, the timing of transmitting responses is controlled depending on, for example, the reception level of the location registration request signal from the wireless telephone.

FIG. 6(a) shows reception when one of the wireless telephones 56, for example, the wireless telephone 56-1, transmits a location registration request signal and the registration request signal is received by each of the fixed devices 53 to 55. The fixing device 53.5
The level at which the response signal returned by No. 4.55 is received by the wireless receiver 56-1 is shown on the time axis. Here, level 57 in FIG. 6(a) indicates the reception level of the location registration signal detected by fixed device 53, level 58 indicates the reception level detected by fixed device 55, and level 59 indicates the reception level of the location registration signal detected by fixed device 54. Represents the detected reception level. Also, Figure 6 (
Level 60 of 5) is the reception level of the response signal detected by the wireless telephone 56-1 from the fixed device 53, level 61 is the level of the response signal transmitted from the fixed device 54, and level 62 is the level of the response signal detected by the wireless telephone 56-1. , respectively represent the level of the response signal transmitted from the fixed device 55.

FIG. 7 shows the sequence of location registration of this wireless telephone 56.

The wireless telephone 56-1 transmits a location registration request signal (2a) to the fixed devices 53 to 55, and each fixed device 53.54
．． 55 receives this location registration request signal and detects its reception level. Then, the detected reception level is sent as a response signal (2) according to the timing determined by the fixed device.
h) , (2c), and (2d) are returned, and the detected reception level at each fixed device is encoded in the response signal and transmitted.

The radio receiver 56-1 determines the representative value of the uplink reception level of the response signal from the fixed devices 53 to 55 and the reception level of the response signal detected by the reception level detection circuit 26 of the own device, that is, the reception level of the downlink. The fixing device with the largest value added to the representative value of the level is selected as the nearest fixing device.

In the example shown in FIG. 7, fixing device 54 is selected as the nearest fixing device. This is because the descending level of the fixing device 55 is larger than that of the fixing device 54 (Fig. 6, etc.).
Level 61 <Level 62) However, since the fixed device 54 is larger than the fixed device 55, the upward level is (
Level 59>Level 58) in Figure 6(a), fixing device 5
This is because 4 is selected. And wireless telephone 56-
1 transmits a location registration notification signal (2e) to the fixed device 54, returns a response signal (2f) from the fixed device 54, and completes the location registration of the wireless telephone 56-1.

〔Effect of the invention〕

As explained above, the present invention detects the reception level of the uplink from the wireless telephone with a fixed device and notifies the wireless telephone. In,
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. Particularly when a plurality of fixed devices are arranged, such as in a multi-zone cordless telephone system, it is convenient for the user to display this reception level when estimating the wireless zone area.

In addition, when using the location registration method of a wireless telephone with a multi-zone cordless telephone system, it selects the most suitable wireless zone compared to selecting the nearest wireless zone and registering the location only at the downlink level or uplink level. This improves the accuracy of zone selection and improves call quality.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining a cordless telephone system. FIG. 2 is a block diagram showing the configuration of a fixing device according to an embodiment of the present invention. FIG. 3 is a block diagram showing the configuration of a wireless telephone according to an embodiment of the present invention. FIG. 4 is a basic control sequence diagram of the embodiment. FIG. 5 is a diagram illustrating the configuration of a multi-zone cordless telephone system. FIG. 6 is a diagram showing an example of the reception level detected by a fixed device in the multi-zone cordless telephone system and the reception level of a response signal. FIG. 7 is a diagram showing a location registration sequence in a multi-zone cordless telephone system. 1.42.52-55...Fixing device, 2.41.56
-1.56-2... Wireless telephone, 3... Wireless line,
4...External line, 5...Fixed communication network, 11...2
Line 4-wire conversion circuit, 12.24...Baseband circuit,
13.22...Transmitter, 14.23...Receiver, 1
5.27...Control circuit, 16.28...Memory circuit, 17.21...Antenna duplexer, 18.34...
Antenna, 19.25...Squelch circuit, 20.26
. . . Reception level detection circuit, 29 . . . Receiver, 30.
...Microphone, 31...Dial key, 32...Display device, 33...Sounder, 51...Line control device. Patent applicant: Nippon Telegraph and Telephone Corporation Representative: Patent attorney Naotaka Ide? 5
Figure (G) Modern Sequence Person's Bag Example Basic Control Sequence Person's Passage 4 ro; ¥16 Figure (1)) Yikaishio I 廇乔 Kidney Explosion Seagen Mata no Naka 5j Shoulder 7 Times

Claims (1)

[Claims] 1. In a cordless telephone system in which one fixed device includes at least one wireless telephone, the fixed device includes means for detecting a reception level of a signal from the wireless telephone; A cordless telephone system characterized by comprising means for notifying the wireless telephone of the level.