JPH08163635A - Controller for burst timing of digital cordless telephone set and control system therefor - Google Patents

Abstract

PURPOSE: To prevent the control burst signals of master sets which are out of synchronism from colliding against each other. CONSTITUTION: This controller is provided with a received high frequency wave circuit part 3 which detects a control channel burst signal sent by another cordless telephone set and a main control part 18 which finds the frame period of the control channel burst signal from the timing of the detected control channel burst signal, controls the transmission timing of its control channel burst signal on the basis of the found frame period so that the signal does not collide against the control channel burst signal of another digital type cordless telephone set, and sends it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to control of burst timing of control burst signals between digital cordless telephones such as mobile telephones, cordless telephones and personal handyphone systems.

[0002]

2. Description of the Related Art FIG. 7 is a block diagram showing a configuration of a master unit of a digital cordless telephone apparatus relating to a speech channel control system of a conventional digital cordless telephone disclosed in, for example, Japanese Patent Laid-Open No. 4-286431. In the figure, 1 is a transmission / reception antenna, 2 is a transmission / reception change-over switch, 3 is a wireless reception unit, 4 is a demodulation unit, 5 is a wireless transmission unit, and 6
Is a modulator, 7 is a communication controller, 8 is a voice coding / combining unit,
9 is a handset having a receiver as a receiver and a microphone as a transmitter, 11 is various key input operation units,
Reference numeral 12 is a telephone line connection unit, and 13 is a slot setting unit.

Next, the operation for securing the own speech channel slot will be described. The slot setting unit 13 connected to the communication control unit 7 detects an empty slot before and during a call and calculates its own slot position information. First, before a call, the communication control unit 7 controls the reception unit 3 to receive a communication signal being performed by a cordless telephone device in the vicinity. That is, the frequency band of the communication channel assigned to the communication system of the digital cordless telephone device is received by the receiving unit 3, and the receiving state is determined by the slot setting unit 13.

Then, when the slot setting section 13 detects the sync word SW from the signal in the period in which the received electric field strength is the highest among the received signals, it is determined that a call is being made on this call channel. At this time, a vacant time during which the received electric field strength on this communication channel does not exceed a predetermined level is detected. It is determined whether or not the detected free time corresponds to the number of slots required for a call within one frame.

When it is determined that the slot required for the call can be secured, the slot setting unit 13 controls
The transmission slot T and the reception slot R are set in this idle time, and the setting information of the transmission slot T and the reception slot R is supplied to the communication control unit 7. Then, the communication control unit 7
Then, the transmission slot T and the reception slot R are set at the timing instructed by the slot setting unit 13 in the communication channel in which the idle time is detected, and the communication with the slave is executed.

When the slot setting unit 13 determines that the slot required for the call cannot be secured, the slot setting unit 13 receives the call channel of another frequency and determines that the slot required for the call can be secured until the slot is available. The detection operation of is executed. Next, the state in which the transmission slot T is set on the basis of the sync word SW will be described. As shown in FIG. 8, the TDMA / TDD communication used in the cordless telephone device of this example requires one frame. 4 transmission slots T1 to T4 and 4 reception slots R
It is assumed that 1 to R4 are set and the multiplexing number is 4.

At this time, as shown in FIG. 8B, when a call using the transmission slot T1 and the reception slot R1 is being performed in the vicinity by another cordless telephone device, the reception electric field strength of this communication channel is shown in FIG. 8A. As shown in the figure, it is determined that a call is being performed by detecting the received electric field strength of a predetermined level or higher in the transmission slot T1 and the reception slot R1. Then, the reception electric field strength is low and it is determined that the reception is not performed (that is, the slots T2 to T2).
T4, R2 to R4), as shown in FIG. 8C, the own transmission slot Ta and reception slot Ra are set.

This own transmission slot Ta is a predetermined time from the end of the sync word SW of the slot with the strongest received electric field strength (that is, the slot T1) among the slots in which it is detected that it is used by another cordless telephone device. It is set at the position where only t _{I has} elapsed. In this way,
Although its own transmission slot Ta is set, when it is determined that communication is being performed by another telephone device at the slot position set by this calculation, another slot position is set by the same procedure.

When the own transmission slot Ta is set, the reception slot Ra is set at a position delayed by 1/2 frame from the transmission slot Ta, and the transmission slot Ta and the reception slot Ra are used. Make a call with the handset.

It should be noted that even during a call, a sync word SW of a slot in which communication is performed by another cordless telephone device is detected every predetermined frame (for example, 25 frames), and from the time when reception of this sync word SW is completed, The time until the start time of the transmission slot T set in the call by this cordless telephone device is detected, and the fluctuation amount of the detected time is monitored. If the amount of fluctuation exceeds a predetermined amount, the position of the transmission slot R is corrected so that the slot used in this cordless telephone device does not collide with the slot used in another cordless telephone device. Control.

[0011]

The above-mentioned prior art is made for effective use of a speech channel, and in the case of a frame having a long frame period (superframe) such as a control channel burst signal, its own method is used. There is a lot of room to set the transmission slot, and the timings of the two units gradually shift due to the deviation of the clock of the master unit, etc., and the fluctuation amount becomes large, which is not optimal for use as it is for the control channel burst signal.

The control channel burst signal is important for confirmation of synchronization between the master unit and the slave unit, originating and terminating calls, and connection processing. To ensure a reliable originating and incoming call, burst signal collision between different master units is required. Must be avoided as much as possible. However, there are only 2 channels, and in the above configuration, there is a risk of collision between the master units connected to the analog telephone line and not synchronized with each other, and effective control channel burst signal collision avoidance measures are required. Met.

The present invention has been made in view of the problems and demands as described above, and controls the master units that are not synchronized with each other with a relatively simple algorithm without imposing a heavy load on software. Burst timing control device and burst timing for digital cordless telephones that can be used in an environment such as an office where a large number of base stations are installed in a small area by preventing collision of channel burst signals. The purpose is to obtain a control method.

[0014]

A burst timing control device for a digital cordless telephone according to the present invention comprises:
A radio signal detecting means for detecting a control channel burst signal emitted from another cordless telephone, a frame period measuring means for obtaining a frame period of the control channel burst signal from the timing of the detected control channel burst signal, and a frame period measuring means of the frame period measuring means. Timing control means for controlling the transmission timing of its own control channel burst signal so as not to collide with the control channel burst signal of another digital cordless telephone based on the measurement result, and the control channel burst signal based on the timing control from this timing control means. And a burst signal transmitting means for transmitting.

Further, the timing control means sets the burst timing of the control channel burst signal of itself to the place where the interval of the burst timing of the control channel burst signal of another digital cordless telephone is the longest.

Further, the timing control means sets the burst timing of the control channel burst signal of itself to the middle of the burst timing interval of the control channel burst signal of the other digital cordless telephone.

Further, there is provided a timing control means including a real-time clock timing means for keeping time, an automatic calling means for automatically making a call to the time signal service at a predetermined time, and a detection means for detecting a notification sound of the time signal service. Is for transmitting the control channel burst signal in synchronization with the signal emitted by the detecting means.

The burst timing control system for a digital cordless telephone according to the present invention uses a plurality of master units each connected to a telephone line, and a master unit provided for each master unit and a wireless line to which the master unit belongs. In a digital cordless telephone equipped with a cordless handset,
Each master automatically makes a call to the time signal service at a preset time and sends a control burst signal in synchronism with the notification sound of this time signal service. The machine detects this, obtains the frame period of the control channel burst signal from the timing of the detected control channel burst signal, and based on this frame period, the control channel burst signal of its own control channel burst signal is set so as not to collide with the control channel burst signal. The transmission timing is controlled and transmission is performed.

[0019]

In the burst timing control device for a digital cordless telephone according to the present invention, when the radio signal detecting means detects a control channel burst signal from another cordless telephone, the frame period measuring means obtains the frame period of this control channel burst signal. The timing control means controls the transmission timing of its own control channel burst signal so as not to collide with the control channel burst signal.

Further, after obtaining the frame period of the control channel burst signal by the frame period measuring means,
The timing control means sets its own control channel burst signal so that it does not collide with other control channel burst signals at the longest burst timing interval.

Further, the timing control means sets its own control channel burst signal at the middle timing of the burst timing interval of the other control channel burst signals, and the control channel burst signals are respectively detected from a plurality of digital cordless telephones. If so, the control channel burst signal of its own is set at the center of the longest burst timing interval of these control channel burst signals.

The timing control means transmits a control channel burst signal in synchronization with the time signal service.

In the burst timing control system for a digital cordless telephone according to the present invention, when a predetermined time comes, the time signal service is automatically called and a control burst signal is transmitted in synchronization with the notification sound of the time signal service. When this control burst signal is detected by another base unit, the frame period of this control channel burst signal is obtained from the timing of the detected control channel burst signal, and the control channel burst signal and its own control channel burst signal do not collide. The transmission timing is controlled so that the signal is transmitted.

[0024]

【Example】

Example 1. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the system configuration of a master unit of the digital cordless telephones according to the present invention.
In the figure, 1 is an antenna for transmission and reception, and 2 is an antenna 1.
The antenna transmission / reception changeover switch 3 connected to the antenna 3 is a reception high frequency circuit unit as a radio signal detecting means connected to the antenna transmission / reception changeover switch 2, and the reference numeral 4 is a demodulation unit connected to the reception high frequency circuit unit 3.

Reference numeral 5 denotes a transmission high frequency circuit section connected to the transmission / reception changeover switch 2 of the antenna, and one of the reception high frequency circuit section 3 and the transmission high frequency circuit section 5 is connected to the antenna 1 by switching the transmission / reception changeover switch 2. . 6 is a modulator connected to the transmission high frequency circuit unit 5, 7 is a time division multiplexing (TDMA) processor connected to the demodulator 4 and the modulator 6,
Reference numeral 8 is a voice encoding / combining unit connected to the time division multiplexing processing unit 7 for performing analog / digital conversion and encoding / compositing of a voice signal, and 9 is a microphone for transmitting and a speaker for receiving. It is a built-in transceiver.

Reference numeral 10 is an analog public line, 11 is a key input operation unit such as a dial, 12 is a 2-line to 4-line conversion unit connected to the handset 9, the analog public line 10 and the voice encoding / combining unit 8. Reference numeral 18 denotes a main control unit for performing various controls in addition to the control according to the present invention, and a frame period measuring means for obtaining a frame period of the control channel burst signal from the detected timing of the control channel burst signal transmitted by another master unit. And the timing control means for controlling the transmission timing of its own control channel burst signal so as not to collide with the control channel burst signal of the other base unit from the obtained frame period, and based on this timing control, its own control channel burst signal A signal is emitted.

Reference numeral 14 is a main control unit 18 and a receiving high frequency circuit unit 3.
A PLL (phase locked loop) synthesizer unit for switching the radio channel frequency, 15 is a reception high-frequency circuit unit 3 which notifies the main control unit 18 that a radio signal from another master unit has been detected. The sensitivity signal 16 is connected to the main control unit 18, and is a clock unit as a real-time clock time measuring means for notifying the date / time / minute / second and measuring the burst signal interval. The parts corresponding to those in the prior art are designated by the same reference numerals.

Next, the operation will be described. FIG. 2 is a flow chart until the main control unit 18 determines the control channel burst signal transmission timing of its own system, which will be described below according to this flow chart. First, when the system is started up (Step 101), the antenna switch 2 is set to the receiving side (Step 102), and the receiving high frequency circuit unit 3 continuously monitors the control channel frequency (St).
ep 103, 104). At that time, since there are two control channels, either channel is arbitrarily selected.

Then, when there is a radio wave of a predetermined detection level or higher, which is transmitted from another master unit or slave unit (St
(Yes in ep105), the reception high-frequency unit 3 detects that fact, and outputs the reception sensitivity signal 15 to the main control unit 18. Since the radio signals are all burst signals, the reception sensitivity signal 15 is intermittently output. Therefore, if the main control unit 18 does not input the reception sensitivity signal 15 within a fixed time (S
(Yes in step 106), the main controller 18 arbitrarily determines the control channel burst signal transmission timing, assuming that there is no other master unit nearby (Step 107),
The time division multiplex processing unit 7 is instructed to transmit the burst signal on the control channel at a predetermined superframe cycle from the determined timing (Step 112).

By the way, while the burst signal of the communication channel transmitted during the voice call has a cycle of 5 msec per frame, the cycle of the burst signal output to the control channel is called "super frame". Is usually 0.8 to 1.2 sec. The length of the burst signal itself is 0.625 μsec, and the relationship is schematically shown in FIG.

FIG. 3 is a timing chart when the superframe has a cycle of 1.2 sec. The upper stage is a control channel burst signal (BCCH) issued by another master unit within the same radio area, and the middle stage is this control channel burst signal. Shows the reception sensitivity signal when the signal is detected, and the lower part shows the timing at which the parent device according to the present invention should send the control channel burst signal. The shaded portion represents the timing of the frame in which the control channel burst signal is transmitted, and the number above it indicates which frame.

Referring to FIG. 2 with reference to FIG. 3, after the system is activated, a control channel burst signal issued by another master unit within the same radio area is received by the high frequency receiving unit 3.
The reception sensitivity signal is output from the reception high frequency unit 3 to the main control unit 18 at the timing shown in the middle part of FIG. 3 (Yes in Step 105). The frame cycle measuring means of the main control unit 18 counts the timing of the reception sensitivity signal and calculates the cycle and the interval (Step 1).
08). Here, there are cases where a plurality of other master devices exist and a plurality of control channel burst signals are detected, so the longest interval is calculated by combining these signals (Step 109).

In the example of FIG. 3, it can be seen that the number of other master devices is one and the frame period thereof is 1.2 sec. The timing control means of the main controller 18 further divides it by 2 to calculate the timing in the middle of the super frame of the other parent device (Step 110). Then, the control channel burst signal transmission timing of the own system is determined from the above result (Step 111). In this example, it is 0.6 sec after the transmission of the control channel burst signal issued by the other base unit.

As shown in the lower part of FIG. 3, the main control unit 18 defines this as the control channel burst signal transmission timing of its own system, and controls the time division multiplexing processing unit 7 so as to transmit the burst signal (STEP 112). . In this way, if the transmission timing is set in the middle of the longest interval of the transmission timing of the control channel burst signal issued by the other parent device, when the mutual timing gradually shifts due to clock deviation, etc. Even if there is a shift, the time until the burst signals collide can be maximized.

Example 2. FIG. 4 is a timing chart of a control channel burst signal when there are a plurality of other master devices in the same area. The configuration of the parent device is the same as that of FIG. 1 shown in the first embodiment. In FIG. 4, among the burst signals indicated by the upper diagonal lines, frame numbers 1 and 241 are frames including the control channel burst signal transmitted by the master unit A, and frame numbers 80 and 321 are frames including the control channel burst signal transmitted by the master unit B. In this example, the master frame A and B both have a superframe period of 1.2 sec.

In such a case, the reception sensitivity signal 15 is shown in FIG.
0.4s starting from frame number 1 as shown in the middle row
It will be output after ec and 0.8 seconds after that. The former time interval is referred to as “interval A” and the latter time interval is referred to as “interval B”. Next, the operation will be described. The basic operation principle is as shown in the flowchart of FIG. 2, and the system startup (Step 10
The operations from 1) to detection of the reception sensitivity signal (Step 105) are the same as in the first embodiment.

In FIG. 2, when the reception sensitivity signal 15 is input to the main control unit 18 (Step 105), the main control unit 1
8 measures this several times, and calculates the interval time from the super frame period regarding the control channel burst signal of the other master unit based on the accurate clock information from the clock unit 16 (Step 108). Then, the periodicity of the burst signal is found and the longest interval is determined (Step 109). According to the example of FIG. 4, 1.2se
The interval B is set as the longest interval by finding the period between c. This interval B
Is 0.8 sec, so divide this by 2 to 0.4 s
ec is calculated (Step 110).

The main controller 18 determines the timing for transmitting its own control channel burst signal 0.4 seconds after the start point of the interval B, that is, the frame number 80 in FIG. 4 (Step 111), and at this timing, the control channel burst of its own. The time division multiplexing processing unit 7 is controlled so as to send a signal (Step 112). In this way, since the transmission timing of the own system is determined by searching for the place with the longest interval, even if there is a deviation in the clock of each master unit and the timings gradually shift from each other, It is possible to reduce the possibility that the control channel burst signals of the above-mentioned collide with each other and become out of synchronization with the slave unit.

Example 3. By the way, according to the methods of the first and second embodiments, the master units having different superframe periods can operate, but burst signal collision will occur sometime. Hereinafter, a method of indirectly synchronizing the master units and preventing collision of control channel burst signals will be described. In FIG. 1, reference numeral 17 denotes a time signal alert sound detection unit that detects a time signal alert sound by the time signal service 117, and the main control unit 18 automatically calls the time signal service 117 at a predetermined time or every predetermined time by a program or the like. It also serves as an automatic calling means, and receives a detection signal from the time signal alert sound detection unit 17.

Next, the operation will be described with reference to the flowchart of FIG. The clock unit 16 in FIG. 1 has a real-time clock, and the main control unit 18 monitors that time reaches the set time. When the set time arrives (Step 201), the automatic calling means of the main control unit 18 controls the 2-wire to 4-wire conversion unit 12 to close the line and dial the 117 time signal service (Step 20).
2). When the time signal service is connected, a notification sound is detected (Step 203). FIG. 6 is a timing chart regarding the present embodiment, and in the figure, "pi, pi, pi, pawn".
It is a time signal alarm sound. This alarm sound is 30
It is sent every second.

The time signal alarm sound detecting section 17 is internally provided with a detector for detecting the frequencies of "pi" and "pawn".
If the "pawn" is detected once after three times, it is judged to have been detected. The notification sound of only the "pawn" is sent out every 10 seconds. However, if only one type of frequency is detected, there is a high possibility that it will be erroneously detected by a voice message or noise that notifies the time. "Pie, pawn" as a set to detect. When this detection is obtained a preset number of times (St
If Yes in ep204), the detection signal is output to the main controller 18 (Step 205).

When the detection signal is input, the main control section 18 controls so that the operation timing of the time division multiplex processing section 7 is synchronized with it. As shown in the timing chart of FIG. 6, 30 sec corresponds to 25 superframes. Therefore, the synchronization accuracy can be increased by performing the synchronization several times continuously by detecting the time signal alert sound. Superframe period is 30 sec, other than 1.2 sec
The same effect can be obtained by setting a divisor. The above operation is performed at a predetermined time, for example, when the time of the real-time clock of the clock unit 16 is 2:00 am, or every predetermined time, for example, every 6 hours or every 12 hours.

With such a configuration, each master unit synchronizes with the time signal service, and as a result, the master units indirectly synchronize with each other. The subsequent operation of determining the transmission timing of the control channel burst signal of the own system is the same as that of the first embodiment.

[0044]

As described above, according to the present invention, the radio signal detecting means for detecting the control channel burst signal emitted from another cordless telephone and the frame of the control channel burst signal are detected from the timing of the detected control channel burst signal. Frame period measuring means for obtaining a period, and timing control means for controlling the transmission timing of its own control channel burst signal based on the measurement result of the frame period measuring means so as not to collide with the control channel burst signal of another digital cordless telephone. Since the burst signal transmitting means for transmitting the control channel burst signal based on the timing control from the timing control means is provided, it is possible to reduce the collision between the control channel burst signal of another master unit and the control channel burst signal of itself. When Cormorants effect can be obtained.

Further, the timing control means sets the burst timing of the control channel burst signal of itself to the place where the interval of the burst timing of the control channel burst signal of the other digital cordless telephone is the longest, so that each digital type is controlled. Even if the burst timings of the cordless telephones are gradually deviated from each other due to the clock deviation or the like, it is possible to further reduce the collision of the control channel burst signals.

Further, since the timing control means sets the burst timing of the control channel burst signal of itself to the center of the burst timing interval of the control channel burst signal of the other digital cordless telephone, each of the digital cordless telephones. It is possible to reduce the collision of control channel burst signals regardless of whether the burst timings of the two channels deviate from each other due to the clock deviation of the control channel burst signals of other digital cordless telephones. If the burst timing interval is set to the longest, the possibility of collision can be further reduced.

Further, the timing control means is provided with a real-time clock timing means for keeping time, automatic calling means for automatically calling the time signal service at a predetermined time, and detection means for detecting a notification sound of the time signal service. Since the control channel burst signal is transmitted in synchronization with the signal emitted by the detection means, the master units can be indirectly synchronized with each other to reduce traffic loss and further reduce the possibility of collision between them. The effect of doing is obtained.

Further, each base unit automatically calls the time signal service at a predetermined time set in advance, transmits the control burst signal in synchronization with the notification sound of the time signal service, and the control burst signal is transmitted. Then, the other base unit detects this, obtains the frame period of this control channel burst signal from the timing of the detected control channel burst signal, and, based on this frame period, does not collide with the control channel burst signal. Since the control channel burst signal transmission timings are controlled and transmitted, the mutual control channel burst signals are synchronized with the time signal service, so that traffic loss can be reduced, and burst control is performed periodically to control channel burst signals. The effect that the collision of signals can be reduced can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a master unit of a digital cordless telephone according to first and second embodiments of the present invention.

FIG. 2 is a flowchart showing an operation of the digital cordless telephone according to the first embodiment of the present invention.

FIG. 3 is a timing chart showing a transmission timing of a control channel burst signal of the digital cordless telephone according to the first embodiment of the present invention.

FIG. 4 is a timing chart showing a transmission timing of a control channel burst signal of the digital cordless telephone according to the second embodiment of the present invention.

FIG. 5 is a flowchart showing the operation of the digital cordless telephone according to the second embodiment of the present invention.

FIG. 6 is a timing chart showing a timing of synchronization setting with a time signal notification sound of a digital cordless telephone according to a third embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a base unit of a conventional digital cordless telephone.

FIG. 8 is a timing chart showing a setting situation of a self slot position of a conventional digital cordless telephone.

[Explanation of symbols]

1 antenna, 2 transmission / reception selector switch, 3 reception high frequency circuit section, 4 demodulation section, 5 transmission high frequency circuit section, 6 modulation section, 7 time division multiplexing processing section, 8 voice encoding / combining section, 9 handset / handset, 10 analog Public line, 11 key input operation unit, 12 2-line to 4-line conversion unit, 14 PLL
Synthesizer section, 15 reception sensitivity signal, 16 clock section, 17 time signal alarm detection section, 18 main control section

Claims (5)

[Claims] 1. A digital cordless telephone having a master unit connected to a telephone line and a slave unit communicating with the master unit via a wireless line, the radio detecting a control channel burst signal emitted from another cordless telephone. A signal detecting means, a frame cycle measuring means for obtaining a frame cycle of the control channel burst signal from the detected timing of the control channel burst signal, and a control channel burst of another digital cordless telephone based on the measurement result of the frame cycle measuring means. A timing control means for controlling the transmission timing of its own control channel burst signal so as not to collide with the signal; and a burst signal transmission means for transmitting the control channel burst signal based on the timing control from this timing control means. And de Burst timing controller for digital cordless telephones. 2. The timing control means sets the burst timing of the control channel burst signal of itself to a place where the interval of the burst timing of the control channel burst signal of another digital cordless telephone is the longest. A burst timing control device for a digital cordless telephone according to claim 1. 3. The timing control means sets the burst timing of the control channel burst signal of itself to the middle of the burst timing interval of the control channel burst signal of another digital cordless telephone. 2. A burst timing control device for a digital cordless telephone set forth in 1 or 2. 4. A timing control means, comprising: a real-time clock for counting time, automatic calling means for automatically calling a time signal service at a predetermined time, and detection means for detecting a notification sound of the time signal service. 2. A burst timing control device for a digital cordless telephone according to claim 1, wherein said means transmits a control channel burst signal in synchronization with a signal emitted by said detecting means. 5. A digital cordless telephone comprising: a plurality of base units each connected to a telephone line; and a base unit provided for each base unit and communicating with a base unit to which the base unit belongs by a wireless line. The base unit automatically calls the time signal service at a preset time, and sends a control burst signal in synchronization with the notification sound of the time signal service.
When the control burst signal is transmitted, the other master unit detects it, obtains the frame period of this control channel burst signal from the timing of the detected control channel burst signal, and based on this frame period, the control channel burst signal. A burst timing control method for a digital cordless telephone, which controls the transmission timing of its own control channel burst signal so that it does not collide with the signal.