JPH0561814B2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a wireless telephone device applying a multi-channel access method, and in particular to a device for detecting an empty channel from among a plurality of wireless channels. Regarding the method of

(Prior Art) Conventionally, a radio telephone device to which a multi-channel access method is applied has been known as one of mobile communication systems. What is multi-channel access method?
This system provides multiple wireless channels to multiple mobile devices, and when making a call, selects an empty channel from among these wireless channels to form a wireless communication path with the parent device, increasing the efficiency of wireless channel usage. can be very useful.

By the way, a radio telephone device to which this type of system is applied is required to perform a so-called free channel search to determine whether each radio channel is free or not when on standby or when making/receiving a call. FIG. 3 is a state transition diagram showing an example of this method. In this method, a random number is first generated from a random number generation circuit, and this random number N is set as the initial value of the wireless channel number when searching for an empty channel ( step
3a). Then, the determination of an empty channel is started from this wireless channel, and each time it is determined that it is in use as a result of this determination, the value of N is incremented in step 3b, and the next wireless channel is determined to be empty. Then, when any wireless channel is determined to be free, the wireless channel number determined to be free is registered in step 3c, and thereafter, in step 3d.
The registered wireless channel is repeatedly monitored for availability. When this wireless channel is in use, N is incremented in step 3b, and a determination is made as to whether another wireless channel is available in step 3a. That is, a free channel search is performed for each wireless channel using the random number N as an initial value until an empty channel is found, and when an empty channel is found, this wireless channel is registered and used during a call. With this method, the free channel search is started using a random number as an initial value, so the wireless channel on which the free channel search is started will be different for each wireless telephone device in the system. It is possible to prevent wireless channels that are registered as being concentrated.

However, such conventional methods require a random number generation circuit to generate random numbers, and since this random number generation circuit is usually constructed from a memory table, the memory capacity increases, increasing the cost of the device and increasing the size of the circuit. This is extremely undesirable.

On the other hand, the present inventor is considering the following method as another free channel search method for solving the above problems. In other words, focusing on the fact that each wireless telephone device in the system has a different number of calls,
Using this number of calls as an initial value, a search for an empty channel for each wireless channel is started. Figure 4 is a state transition diagram showing this method.
The number of calls D is set as an initial value in steps 4a and 4b. With this type of system, only one memory for counting the number of calls is required, so the memory capacity does not increase as much as in the case of a random number generation circuit, and therefore an apparatus can be constructed at low cost and with a small circuit scale.

However, the method proposed by the present inventors has the following problems. In other words, when a power outage occurs, or even when there is no power outage, offices may leave a small number of wireless telephone devices in place and turn off the power to other devices at night. The contents of the memory that stored the initial value of channel search will be cleared. For this reason, when the power is restored to each wireless telephone device, the initial value of the free channel search of these wireless telephone devices is shared by the value after clearing, and many wireless telephone devices each have this initial value. Since the free channel search starts from
There was a problem in which wireless channels that were registered as free channels were concentrated and some wireless channels were used more frequently.

(Problem to be Solved by the Invention) As described above, in the above method, the initial value of the wireless channel number for searching for an empty channel is cleared when the power is turned off, so the wireless channel that is registered as an empty channel immediately after the power is turned on is There is a problem in that the channels are concentrated on a specific channel, leading to a decrease in the usage efficiency of the wireless channel and an extension of the connection time. It is possible to prevent wireless channels from concentrating on a specific channel, thereby improving the efficiency of wireless channel usage and shortening the connection time of wireless communication paths. It is an object of the present invention to provide an empty channel search method that does not limit the storage of information and thereby allows a device circuit to be constructed simply, compactly, and at low cost.

[Structure of the Invention] (Means for Solving the Problems) The present invention focuses on the fact that wireless telephone devices having a speed dialing function are usually equipped with a nonvolatile memory for speed dialing, and the present invention is based on FIG. As shown in the figure, the parent device is provided with an initial value storage control means A and a search control means B, and the initial value storage control means A counts the total number of calls every time a call is made, and based on this count. The obtained value of the number of calls is stored in the non-volatile memory as an initial value of a wireless channel number for searching for an empty channel, and is stored in the non-volatile memory by the search control means B at the time of searching for an empty channel. The free channel search is started from the wireless channel specified by the number of calls made.

(Function) As a result, even if the power of the parent device is cut off, the number of calls for free channel search stored in the nonvolatile memory is not erased and is preserved as is. Therefore, the search for an empty channel immediately after the power is turned on will start from the wireless channel specified by the number of calls before the power is turned off, which is stored in the non-volatile memory. The problem that registered wireless channels are concentrated on a specific channel is eliminated, and as a result, it is possible to improve the usage efficiency of wireless channels and shorten the line duration.

In addition, only the initial value of the wireless channel number for free channel search is stored in the non-volatile memory, and this initial value is a numerical value representing the number of calls.
Therefore, the capacity of the nonvolatile memory required to store this information is small (for example, about several bits). Therefore, there is no need to newly provide a large-capacity nonvolatile memory, and in order to store information for the above-mentioned free channel search, the number of registered information that should be stored, such as speed dial number information, is limited. There's no need.

(Embodiment) FIG. 2 shows the configuration of a wireless telephone device to which a free channel search method is applied in an embodiment of the present invention. 2, and a wireless telephone 4 as a mobile device connected to the parent device 2 via a wireless line 3.

First, the parent device 2 uses the synthesizer (SYN) 21
It is equipped with a transmitter (TX) 22 and a receiver (RX) 23 in which transmitting and receiving channels are designated by a line relay 24 and a hybrid circuit 25. Thereafter, the transmitter 22 modulates the signal and sends it from the transmitting antenna 26 to the radio line 3, and the radio communication signal that arrives from the radio telephone 4 via the radio line 3 is guided from the receiving antenna 27 to the receiver 23 and demodulated, and then the above-mentioned signal is transmitted. It is sent to subscriber line 1 via hybrid circuit 25 and line relay 24. The main device 2 also includes an incoming call detection circuit 28 for detecting a 16Hz ringing signal arriving from the exchange via the subscriber line 1, and a receiving electric field as circuits necessary for connection between the subscriber line 1 and the wireless telephone 4. Detection circuit (C-DET) 29 and identification signal detection circuit (ID-
DET) 30 and memory 3 for speed dialing
5 and a control circuit (CONT) 31.
Of these, the received electric field detection circuit 29 is comprised of a carrier squelch or noise squelch circuit, and monitors the arrival of radio waves from the radio telephone 4. The identification signal detection circuit 30 verifies an identification signal (ID code) determined in advance by the combination of the parent device 2 and the radio telephone 4, and notifies the control circuit 31 of the verification result. In addition, the memory 35 for speed dialing stores the desired telephone number of the other party.
When an abbreviated dial number is sent from the radio telephone 4 at the time of making a call, the corresponding telephone number of the other party is read out under the control of a control circuit 31. Also this memory 35
is backed up by a battery 36 so that its memory contents will not be erased in the event of a power outage. In addition, 32 is a rectification stabilization circuit that generates a predetermined operating voltage Vcc from the commercial power supply output and transfers this operating voltage Vcc to the parent device 2.
Current limiting resistor 3
4 and the power supply terminal 33 to the wireless telephone 4 as a charging voltage.

By the way, the control circuit 31 has, for example, a microcomputer as its main control section, and in addition to the connection control means for the wireless line 3, it has an empty channel search control means and an initial value storage control means. The initial value storage control means includes a counter that counts the number of calls, and uses the number of calls counted by this counter at each end of a call as the initial value of the wireless channel number for searching for an empty channel in the memory 35 for making the speed dial call. This is what you write in. The search control means searches for an empty channel by sequentially checking the availability of each wireless channel periodically during standby or when making a call. Start with a channel.

On the other hand, the wireless telephone 4 is equipped with a transmitter (TX) 42 and a receiver (RX) 43 whose transmitting and receiving channels are designated by a synthesizer (SYN) 41, like the parent device 2 described above.
The antenna 44 receives the wireless communication signal that has arrived via the antenna 44.
The signal is guided to the receiver 43 via the receiver 43 and demodulated, and then outputted as voice from the receiver 45. The speech signal input from the transmitter 46 is modulated by the transmitter 42, and then sent from the transmitting antenna 47 to the wireless line 3. There is. This wireless telephone 4 also includes a transmission switch 48, a dial key 49, a received electric field detection circuit (C-DET) 50, an identification signal detection circuit (ID
-DET) 51, a sounder 53 that generates a sound, and a control circuit (CONT) 52 that performs various controls related to connections. Note that 54 is a battery, which is charged by the operating voltage Vcc supplied from the parent device 2 via a charging terminal 55.

Next, the free channel search method of this embodiment will be explained based on the above configuration. First, when a call is made, the number of calls is counted by the control circuit 31, and when the call ends, the number of calls stored in the memory 35 is rewritten.

Now, during standby, the control circuit 3 of the parent device 2
1 is the memory 35 at a predetermined period, for example every 3 seconds.
The number of calls is read from , and the radio channel specified by the number of calls is first set in the synthesizer 21 and the receiver 23 is operated, thereby determining whether the radio channel is vacant. Then, if it is determined that a wireless channel is blocked, that is, in use, the next wireless channel is selected and similarly checked for availability, and in the same way, each wireless channel is selected in turn until a free channel is found and its availability determined. Do the following. That is, the search for free channels is started in order from the wireless channels corresponding to the number of calls stored in the memory 35. When a free channel is detected in any wireless channel, the control circuit 31
stores the number of this free channel in its internal memory, and thereafter repeatedly monitors the availability of this wireless channel. Incidentally, instead of just one empty channel, a plurality of channels may be stored and the vacancies may be monitored sequentially. Furthermore, when any wireless channel becomes in use during monitoring of free channels, the control circuit 31 erases the number of this wireless channel from the internal memory and then starts a search to find a new free channel.

On the other hand, when an incoming call occurs from, for example, the subscriber line 1 side in this standby state, and this is detected by the incoming call detection circuit 28, the control circuit 31 selects a wireless channel stored in the internal memory as an empty channel and uses the synthesizer. 21, and operates the transmitter 22 to transmit a connection request to the radio telephone 4, and thereafter performs connection control using well-known procedures.

By the way, if the power to the parent device 2 were to be cut off due to a power outage or turning off the power switch, the control circuit 31 and other circuits in the parent device 2 would be in a stopped state. However, since the memory 35 for speed dialing is receiving battery backup, its operation is maintained, and as a result, the destination telephone number and the number of calls for free channel search stored in this memory 35 are not erased. is retained as is. Therefore, after the power is restored, the control circuit 31 of the parent device 2 selects a wireless channel according to the number of calls that remains the same as before the power was turned off, and starts searching for an empty channel.
Therefore, the starting channels of the free channel search of each radio telephone device immediately after the power is restored are concentrated on one channel, and this eliminates the problem that the radio channels stored as free channels are concentrated in some channels. Therefore, it is possible to register each wireless channel as an empty channel evenly between each wireless telephone device, thereby increasing the usage efficiency of wireless channels, shortening the duration, and performing smooth connection control. becomes possible. Furthermore, since the existing memory for speed dialing is used as the nonvolatile memory for storing the number of calls, there is no need to use a new nonvolatile memory, and as a result, the present invention can be realized at low cost and with a simple configuration.

Note that the present invention is not limited to the above embodiments. For example, as non-volatile memory, in addition to battery-backed memory, RAM with a self-holding function may be used.In short, any memory that is non-volatile and can be randomly accessed may be used. . In addition, the control procedures and control contents of the search control means and initial value storage control means, the circuit configurations of the parent device and the radio telephone, etc. can be modified in various ways without departing from the gist of the present invention.

[Effects of the Invention] As described in detail above, the present invention provides the parent device with the initial value storage control means A and the search control means B, and the initial value storage control means A performs the search every time a call is made. Count the total number of calls,
The value of the number of calls obtained by this count is stored in the non-volatile memory as the initial value of the wireless channel number for searching for an empty channel, and when searching for an empty channel, the value of the number of calls obtained is stored in the non-volatile memory by the search control means B. An empty channel search is started from the wireless channel specified by the stored number of calls.

Therefore, according to the present invention, wireless channels that are registered as empty channels immediately after power is turned on can be prevented from concentrating on a specific channel,
This makes it possible to improve the efficiency of wireless channel usage and shorten the duration of wireless communication paths.
Moreover, it is an object of the present invention to provide an empty channel search method that does not require a large-capacity nonvolatile memory, does not limit the storage of other information, and can thereby easily and inexpensively configure a device circuit. can.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram showing the configuration of the free channel search method of the present invention, FIG. 2 is a circuit block diagram of a wireless telephone device to which the free channel search method according to an embodiment of the present invention is applied, and FIGS. FIG. 4 is a state transition diagram for explaining different conventional free channel search methods. A... Initial value storage control means, B... Search control means, 1... Subscriber line, 2... Parent device, 3... Radio line, 4... Wireless telephone, 21, 41... Synthesizer, 22, 42...Transmitter, 23,43...
... Receiver, 24 ... Line relay, 25 ... Hybrid circuit, 26, 47 ... Transmission antenna, 2
7,44...Receiving antenna, 28...Incoming call detection circuit, 29,50...Receiving electric field detection circuit, 30,5
1...Identification signal detection circuit, 31, 52...Control circuit, 32...Rectification stabilization circuit, 33...Power supply terminal, 34...Current limiting resistor, 35...Memory for speed dialing, 36... Backup battery, 45...Telephone receiver, 46...Telephone transmitter, 48...
Call key, 49... dial key, 53... sounder.

Claims (1)

[Scope of Claims] 1. Consists of a parent device connected to a wired line and equipped with a non-volatile memory for making speed dial calls, and a mobile device connected to the parent device via a wireless communication path. In the free channel search method of a wireless telephone device, which selects an empty wireless channel from among a plurality of wireless channels and forms a wireless communication path between a parent device and a mobile device via this wireless channel, a call is made. initial value storage control means for counting the cumulative number of calls each time the call is received, and storing the value of the number of calls obtained by this count in the nonvolatile memory as an initial value of a wireless channel number for searching for an empty channel; and the free channel search for each wireless channel.
An empty channel search method comprising: a search control means that starts from a wireless channel specified by the number of calls stored in the nonvolatile memory.