JP2788256B2 - Free channel search method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a multi-channel access system for detecting an empty radio channel among a plurality of radio channels and transmitting and receiving voice or data. The present invention relates to a wireless telephone device, and particularly to an empty channel search method.

(Prior Art) FIG. 3 is a block diagram showing a conventional configuration of this type of wireless telephone device. In FIG. 1, a parent device 1 is connected to a wireless telephone 2 via a wireless line, and is also connected to a wired telephone line 3.

The signal transmitted from the wired telephone line 3 becomes a modulation input of the transmitter 5 via the hybrid circuit 4. The radio wave modulated by the transmitter 5 is transmitted to the wireless telephone 2 by the antenna 6.

On the other hand, the radio wave transmitted by the wireless telephone 2 is received by the antenna 7 and demodulated by the receiver 8. The demodulated signal is transmitted to the wired telephone line 3 via the hybrid circuit 4.

Synthesizer 9 outputs a signal of a frequency corresponding to a radio channel (a communication channel and a control channel) to transmitter 5 and receiver 8.

One of the demodulated outputs of the receiver 8 is input to the reception electric field detection circuit 10 and is used for determining the electric field strength. This circuit
10 is generally called a carrier squelch circuit or a noise squelch circuit. Another demodulated output is output as a data signal included in the received demodulated wave, and is input to an identification signal detection circuit 11 that checks an identification signal determined by a combination of the parent device 1 and the wireless telephone 2. This identification signal is generally called an ID code.

The outputs of the detection circuits 10 and 11 and the demodulated output of the data signal are input to the control circuit 12 and used for connection control.
The control circuit 12 controls the switching of the radio channel by controlling the synthesizer 9 and controls the transmission of a transmission data signal to the transmitter 5 as a modulation input.

On the other hand, the antenna 13 and the receiver 14
Is provided, and the demodulated output of the receiver 14 is output to the receiver 15. The voice input from the transmitter 16 is
It becomes the modulation input of 17 and is transmitted by the antenna 18.

The synthesizer 19, the reception electric field detection circuit 20, and the identification signal detection circuit 21 are the same as those in the parent device 1, and the control circuit 22 controls the wireless telephone 2. The speaker 23 is a sounder that emits a ringing tone when receiving a call. In these power supply systems, the parent device 1 has an AC plug 24 connected to AC100V, and uses the output of the rectification and stabilization circuit 25 in each circuit. The output of the stabilizing circuit 25 is supplied to a chargeable battery 29 of the wireless telephone 2 via a current limiting resistor 26 and charging terminals 27 and 28, and the output of the battery 29 is used as a power supply of the wireless telephone 2. . Reference numeral 30 denotes a dial key.

However, the general control at the time of incoming call in this conventional example is performed as follows.

When a call signal from the wired telephone line 3 is detected by a call signal detection circuit (not shown) during standby, the parent device 1 sets the oscillation frequency of the synthesizer 9 to the control channel frequency, turns on the transmitter 5, and turns on the incoming call. Send a signal. in this case,
The incoming signal includes a signal for specifying a communication channel (S-CH).

On the other hand, the radiotelephone 2 turns on the synthesizer 19 for a certain time during standby, sets its oscillation frequency to the control channel frequency, and turns on the receiver 14. At this time, when an incoming signal is received, the transmitter 17 is turned on, an incoming response signal including an ID code assigned to itself is transmitted, and switching to the communication channel (S-CH) designated by the parent device 1 is performed. .

When the reception electric field detection circuit 10 detects a radio wave from the wireless telephone 2, the parent device 1 stops transmitting the incoming signal. next,
When the ID codes included in the incoming call response signal match, switching to the S-CH specified by the incoming signal is made. Here, if the ID codes do not match, it is a response from another set of wireless telephones, and the process returns to standby after waiting for the call from the wired telephone line 3 to disappear.

After switching to S-CH, parent device 1 sends a bell ringing signal. When the wireless telephone 2 receives this, the sounder 23 sends out a ringing tone. Therefore, when an off-hook operation is performed in response to this, the wireless telephone 2 sends an off-hook signal, and the telephone enters a call state.

On the other hand, upon receiving the off-hook signal, the parent operation 1 stops transmitting the bell ringing signal, forms a communication loop with the wired telephone line 3, and enters a communication state.

On the other hand, the operation when making a call from the wireless telephone 2 is as follows. That is, when an off-hook operation is performed to make a call to the wired telephone line 3, the control circuit 22 locks the oscillation frequency of the synthesizer 19 to the control channel, turns on the receiver 14, and sets the control channel (C-CH). To receive radio waves. Then, the electric field strength of the received radio wave in the control channel is detected by the detection signal of the reception electric field detection circuit 20, and if there is no reception electric field strength exceeding a certain value, it is determined that the control channel is empty, and the transmitter 17 is turned on. As a call signal including an ID code assigned to itself. On the other hand, the parent device 1 monitors the presence or absence of the received radio wave of the control channel. However, when receiving the call signal from the wireless telephone 2, the ID code therein is assigned to the combination with the wireless telephone 2. It is determined whether or not the ID code matches the ID code, and if the ID code matches, the transmitter 5 is turned on and a call response signal (including ID code and S-CH designation information) is transmitted to the wireless telephone 2. Let it.

The radio telephone 2 receives the call response signal from the parent device 1 on the control channel, detects whether or not the ID code included in the response signal matches its own ID code. The 19 oscillation frequency is switched to the frequency of the communication channel designated by the master device 1. On the other hand, after transmitting the call response signal, master device 1 also switches the oscillation frequency of synthesizer 9 to the frequency of the communication channel designated for communication.

As a result, the parent device 1 and the wireless telephone 2 are connected via the communication channel designated by the parent device 1, and the subsequent dial operation using the dial key 30 causes the wired telephone line 3 to be connected.
Can be called to place the telephone connected to the telephone.

By the way, when an incoming call is made from the wired telephone line 3 and an outgoing call is made from the wireless telephone 2, the parent device 1 detects an empty communication channel used for communication with the wireless telephone 2 as follows. . That is, the master device 1 alternately switches the reception channel between the control channel and one of the communication channels during standby, monitors the call from the wireless telephone 2 on the control channel, and when the currently selected communication channel becomes available. I'm monitoring for If the currently selected call channel is free, the channel is registered as a free channel.

FIG. 4 is a state transition diagram showing a conventional procedure of such an empty channel detection process. First, an initial value D or "N = N + 1" is set as a channel number N for empty channel detection by turning on the power or ending the call. Set (Step 4
a, 4b). Next, a reception channel is set to the communication channel S-CH (N) of the number indicated by the initial value D, and it is checked whether or not this reception channel is free (step 3a). As a result, if free, S-CH (N) is registered as a free channel (step 3b). However, when it is not empty, the channel number N is updated to "N = N + 1" (step 3c), and the empty state of this new communication channel S-CH (N) is checked.

In this manner, an empty communication channel is detected and registered. When a plurality of sets of wireless telephone devices are used in adjacent areas, the communication channel registered as an empty channel is replaced by another set of wireless telephone devices. , It becomes impossible to immediately specify a communication channel for an incoming call from a wired telephone line or a call from a wireless telephone. Therefore, two or three unused communication channels are registered conventionally, and after the registration is completed, the registered communication channels are monitored. 3d), the channel number N is updated to “N = N + 1”, and a vacant state of another communication channel is detected.
It is configured to secure an empty channel.

(Problems to be Solved by the Invention) However, the initial value D of the channel number N set when the power is turned on is the same value even when a plurality of sets of wireless telephone devices are used in adjacent areas. Moreover, the number of updates when the channel is not empty (that is, the channel interval for detecting an empty channel) has the same value (= + 1). For this reason, when the power supply of each set of parent devices is momentarily interrupted due to a power failure or the like, each set of parent devices starts detecting an empty channel starting from the same communication channel. As a result,
A phenomenon occurs in which the number of the call channel registered as an idle channel is shifted to a channel near the initially set call channel. There has been a problem that connection of a wireless line becomes impossible.

The present invention is capable of simultaneously detecting the power supply of each set of parent devices due to a power failure or the like and then simultaneously activating each set of parent devices, by dispersing and detecting empty wireless channels, and immediately after starting operation. In this way, vacant channel detection is performed only on radio channels near a specific radio channel,
It is an object of the present invention to provide an empty channel search method that can prevent a situation in which connection of a wireless line cannot be performed smoothly.

[Configuration of the invention]

(Means for Solving the Problems) The present invention is configured by arranging a plurality of sets of a parent device connected to a wired telephone line and a wireless telephone connected to the parent device by a wireless line. In a multi-channel access type wireless telephone device that detects an empty wireless channel from among a plurality of wireless channels and connects the parent device to the wireless telephone, when the power is turned on, the parent device cannot be externally set. Set to an initial value specific to the parent device,
Numerical information generating means for generating numerical information that advances by cyclic change numerical information that cyclically changes at a numerical interval specific to the parent device, and an empty radio channel according to the numerical information generated by the numerical information generating means Is detected.

(Operation) In each set of parent devices, the numerical information generating means is set to an initial value that cannot be set from outside and is unique to the parent device when the power is turned on. The step-by-step changing numerical information generates numerical information that advances. Then, the parent device detects an empty wireless channel according to the numerical information generated by the numerical information generating means.

Therefore, even when a plurality of sets of parent devices used in the adjacent area are momentarily interrupted due to a power failure or the like, and then these parent devices are simultaneously activated, the first communication channel number for performing an idle channel is the parent device. Different from one another, the communication channels detected as idle channels are dispersed when viewed from the whole of a plurality of adjacent wireless telephone sets.

FIG. 1 is a block diagram showing one embodiment of the present invention.
The difference from the conventional configuration is that a free-run counter 41 and a channel interval counter 42 are provided in the parent device 1.

The free-run counter 41 and the channel interval counter 42
Cooperates with the control circuit 12 to generate numerical information for detecting an empty channel which starts from an initial value specific to the parent device 1 and changes at a specific interval. D, and the channel interval counter 42
The control circuit 12 generates a numerical value n that changes cyclically in the form of 2,3 ... 8,1,2,3. The control circuit 12 starts from an initial value D, and adds the output value n of the channel interval counter 42 to the initial value D, thereby providing a free space. A channel number N for channel detection is generated.

The free-run counter 41 is a commonly used octal, 1
This is a k-ary counter such as a 0-base counter, and is initially set to an unspecified value due to variations in the characteristics of internal transistors when the power is turned on. Then, the count value sequentially changes according to a clock signal output from an oscillator such as a crystal oscillator used in the control circuit 12. In this case, the frequency of the clock signal is unstable until a certain time elapses after the power is turned on. Accordingly, the numerical information output from the free-run counter 41 has its initial value D at power-on.
Is an unspecified value, and the rate of change until a certain time elapses is also a random change depending on the characteristics of the oscillator. That is, from the free-run counter 41, the parent device 1
Numerical information starting from a unique initial value D corresponding to a combination of the characteristics of the circuits constituting each of the components is output at a unique change rate, while the channel interval counter 42 has a count value of 1, 2, 3 as described above. 8, 1, 2,..., And the count value is updated by the control circuit 12 when the communication channel to be detected is idle.

FIG. 2 is a state transition diagram showing an empty channel detecting process in such a configuration. When the power is turned on, the count value n of the channel interval counter 42 is set to n = n by the control circuit 12.
Initially set to 1 (step 5a). Next, the output numerical information of the free-run counter 41 is set as the initial value D of the channel number N for detecting an empty channel (step 4).
b). Therefore, the control circuit 12 sets the oscillation frequency of the synthesizer 9 to the communication channel frequency indicated by the initial value D,
The receiver 8 is set to the reception state of the communication channel, and after a predetermined time, it is checked whether or not the reception electric field is detected by the reception electric field detection circuit 19 (step 3a). As a result, if there is a reception electric field, it is assumed that the communication channel indicated by the initial value D is closed, and the channel number N is updated to "N = N + n" (step 3c), and the communication channel which is n channels away is vacant. Check the status.

However, if the communication channel indicated by the initial value D is vacant, the output numerical information n of the channel interval counter 42 is changed to “n”.
= N + 1 "(step 5d), and thereafter, the initial value D
Is registered as a free channel (step 3b). And the number of registered free channels is 3
If the channel has not been reached, the channel number N is set to "N =
N + n "and check the vacant state of the communication channel n channels away.

When three free channels are registered in this way, the operation moves to the monitoring operation of these free channels (step
3d), if any one becomes blocked, the registration of the empty channel is deleted, the channel number N for detecting the empty channel is updated to "N = N + n", and the process proceeds to the detection of a new empty channel.

However, if it is not in the closed state, the monitoring of the currently registered free channel is continued while updating the numerical value information n of the channel interval counter 42 to “n = n + 1”.

In the case of the end call, N is set to “N = N + n”,
It is checked whether or not the communication channel indicated by the new channel number N is free (step 4a).

As described above, in the present embodiment, since the detection of an empty channel is performed according to the channel number N starting from the initial value D unique to the parent device 1, each wireless telephone device is arranged when a plurality of wireless telephone devices are arranged adjacently. Unused channels detected by the device are dispersed. As a result, it is possible to solve a situation in which a wireless line cannot be connected even if incoming and outgoing calls are concentrated.

In the embodiment, the free-run counter 41 generates the channel number N starting from the initial D unique to the parent device using the variation in the characteristics of the clock oscillator.
In addition, it is also possible to use a random number generation circuit to generate a channel number N which changes at random, thereby detecting an empty channel. Further, the channel interval is “1”, but may be a discrete interval such as “3”, “5”, or “7”.

〔The invention's effect〕

As described above in detail, according to the present invention, when the power is turned on, each set of parent devices cannot be set from the outside and is set to an initial value unique to the parent device. In order to detect an idle wireless channel according to the numerical information stepping by the cyclic change numerical information that cyclically changes at the numerical intervals of the following, after the power supply of the parent device of each set is momentarily interrupted due to power failure or the like, the When the parent device is started up at the same time, the radio channels for determining the available channels can be distributed to each set of the parent device, and the connection of the radio line can be performed smoothly even for the concentration of incoming and outgoing calls immediately after startup. Moreover, the means for generating the numerical information can be realized by means other than the random number generator such as a free-run counter and a cyclic counter, and has an excellent advantage that the configuration and control can be simplified.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a position embodiment of the present invention, FIG. 2 is a state transition diagram showing empty channel detection processing in the embodiment, FIG. 3 is a block diagram showing a configuration of a conventional radio telephone apparatus, FIG. FIG. 1 is a state transition diagram showing a conventional empty channel detection process. DESCRIPTION OF SYMBOLS 1 ... Parent apparatus, 2 ... Wireless telephone, 3 ... Wired telephone line, 4 ...
Hybrid circuit, 5,17… Transmitter, 8,14… Receiver, 9,19
... Synthesizer, 10,20 ... Reception electric field detection circuit, 11,21 ... Identification signal detection circuit, 12,22 ... Control circuit, 15 ... Handset, 16 ...
Transmitter, 23 speaker, 29 battery, 41 free-run counter, 42 channel interval counter.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuji Ota 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Shoji Fuse 3-1-1 Asahigaoka, Hino-shi, Tokyo 1 share (56) References JP-A-63-222524 (JP, A) JP-A-59-95738 (JP, A) JP-A-55-78341 (JP, A) JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) H04B 7/24-7/26 H04Q 7/00-7/38

Claims (1)

(57) [Claims] The present invention comprises a plurality of sets of a parent device connected to a wired telephone line and a plurality of wireless telephones connected to the parent device by a wireless line. In a multi-channel access type wireless telephone device for detecting a wireless channel of the wireless communication device and connecting the parent device to the wireless telephone, when the power is turned on, the parent device cannot be externally set and has an initial value unique to the parent device. Numerical information generating means for generating numerical information that advances by cyclic change numerical information that cyclically changes at a numerical interval unique to the parent device thereafter, wherein the numerical value generated by the numerical information generating means is provided. An empty channel search method characterized by detecting an empty wireless channel according to information.