JPH02249326A - Idle channel designation system - Google Patents

Abstract

PURPOSE:To ensure the connection and to reduce the time required for connection by sending plural sets of idle channel information from a connector at the time of setting a radio line when an incoming or outgoing call while an idle channel is sought in advance, and designating the channel. CONSTITUTION:In the absence of the incoming call and outgoing call to both a connector and a portable telephone set, a receiver is sometimes operated to seek an idle channel and plural sets of idle channel information are stored in a storage section of a control section. In the presence of an incoming call to the connector, the connector confirms an idle control channel to call the portable telephone set. When an idle channel is confirmed, the connector uses an outgoing control channel (from connector to portable telephone set) to send a call signal plus idle channel information to send a signal to the portable telephone set. The portable telephone set collates whether the idle channel information sought in advance and the information sent from the connector are coincident and selects one of coincident channels and sends the result to the connector through the incoming control channel (connector from portable telephone set) together with a call replay signal. Thus, in the worst case, the portability of generation of an unconnected state is reduced.

Description

[Detailed Description of the Invention] (1) Technical field to which the invention pertains The present invention relates to a system such as a cordless telephone that can make or receive calls from a mobile location, and when performing a wireless connection using a multi-channel access method. The present invention relates to an improved method for specifying an empty communication channel when searching for an empty communication channel for wireless connection.

(2) Conventional technology and its problems Current cordless telephones wirelessly connect a connection device connected to a public line and a battery-operated mobile phone.
Makes and receives calls.

In the wireless system, the receiver of the mobile phone receives the Fl radio waves sent from the transmitter of the connecting device, and the receiving face of the connecting device receives the FL radio waves sent by the transmitter of the mobile phone.
(See Figure 1). Pi and fl are generally separated by 5% or more, but currently Fl is 380MIIZ, f
l is 250M1lZ. There are several dozen sets of radio waves that this connection device and mobile phone can transmit (currently 89
&11) At least one set of channels is designated as a control-only channel and is not used for telephone calls.

To select one channel from these multiple sets, first select the channel that is being used, because if you select the channel that is already in use, it will cause interference to other stations or receive interference from other stations. It checks in advance to see if it is vacant, and after confirming, transmits radio waves to prevent interference. In this method, the squelch level of the receiver of the connecting device and the mobile phone is taken into each control section and judged. This radio control is called a multi-channel access method and is generally widely used.

A conventional example of radio line control is shown in FIG.

This figure shows an example in which a call is received from the outside to the connected device.

First, when a call arrives at the connecting device, the control unit of the connecting device confirms that the control channel is free. When it is confirmed that the mobile phone is free, the mobile phone is called along with the information of one free call channel found in advance. The mobile phone that receives this sends a call response signal to the connection device. Based on this answer, both the connecting device and the mobile phone switch to the communication channel. When switching to a voice channel, reconfirm that this channel is free before transmitting radio waves. When the mobile phone confirms that the channel is free, it sends a channel switching completion signal to the connecting device through the uplink communication channel. On the other hand, the connecting device replies to the mobile phone via the downstream communication channel that it has received the same signal. Thus, a call channel loop can be formed and call processing (such as ringing) can be entered.

The above is an example of a successful connection. In reality, connection failures, connection re-connections, etc. often occur. In cases like this, the connection device and mobile phone may be far apart and the signal may be weak.
This is likely to occur in locations with a lot of noise from computers, motors, etc., or where many similar systems are used. The cause may be that noise is mixed into the radio waves used for exchanging control signals, or the channel specified by the connecting device is not available on the mobile phone side, or the connecting device and mobile phone are several tens of meters apart. In principle, there is a possibility that the determination of ``vacancy J'' confirmed by the connecting device and the ``vacancy'' seen on the mobile phone side do not match.

Further, the channel determined by the connecting device is the frequency fx transmitted by the mobile phone, and the channel determined by the mobile phone is the frequency Fx transmitted by the connecting device.There may be cases where the two do not match. As mentioned above, reconnection occurs for various reasons.

FIG. 3 shows an example of a case where the communication channel specified by the connection device on the mobile phone is blocked. The steps up to the middle are the same as those shown in FIG. 2, except that if the communication channel specified by the connection device is blocked, the mobile phone does not send a channel switching completion signal (indicated by a dotted line). Since the mobile phone cannot find a free communication channel, it switches to the original control channel and receives the next instruction. Even after waiting for a certain period of time, the connecting device does not receive a channel switching completion signal from the mobile phone, so it returns to the original control channel and detects whether the control channel is available. After confirming availability, a calling signal and a different available channel than the previous one are specified and sent to the mobile phone again. The subsequent procedures are the same as those shown in FIG. Therefore, it will take more than twice as long as it would take to connect normally. Naturally, if you repeat redo many times, the control n channel will be occupied for a long time, making other systems unusable.Also, in the worst case, the connection It may not be possible to do so.

(3) Purpose of the Invention In order to eliminate such drawbacks, the present invention searches for vacant channels in advance on the mobile phone side, and sends out information on a plurality of vacant channels from a connecting device when setting up a wireless line when receiving or outgoing calls. By selecting a matching one from this data and specifying an empty channel, repetition as in the conventional example can be prevented, ensuring a secure connection, shortening the connection time, and shortening the transfer of the control channel to other systems. It was designed to be done on time.

(4) Structure and operation of the invention A connection flow of the invention is shown in FIG. This will be explained below with reference to FIG. Regarding hardware, please refer to Part 1.
It is the same as shown in the figure.

First, when there is no incoming call or outgoing call on either the connecting device or the mobile phone, the receiver is operated from time to time to search for an empty channel, and information on a plurality of empty channels is stored in the storage section of the control section. To determine whether a channel is vacant, the squelch level from the receiver shown in FIG. 1 is taken into the control section, and if the signal level is below a certain signal level, it is determined to be vacant. This channel number is stored in the storage section of the control section, and then the control section issues a command to the frequency synthesizer to receive another channel, and receives the other channel. If the reception level is above a certain reception level, the next channel is received without storing it in the storage unit. This operation is repeated one after another to store information on about five vacant channels in the storage section. When about five free channels are found, the control section suspends this operation for a while, and then repeats the same operation after a while to constantly store fresh free channel information in the storage section.

If the connected device receives a call at this point, the connected device will
Check the availability of the control channel to call the mobile phone. When availability is confirmed, the connecting device sends a signal to the mobile phone on a downlink control channel (from the connecting device to the mobile phone) carrying a calling signal plus information on the empty channel. At this time, good results can be obtained by transmitting the vacant channel information not only for one channel but also for at least three to five channels.

The mobile phone that receives this information checks whether the information sent from the connecting device matches the available channel information that it has searched for in advance. If there is a matching free call channel among both signals, the mobile phone selects one and sends it to the connected device along with a call response signal on an uplink control channel (from the mobile phone to the connected device). The connecting device receives this and switches the frequency to the designated communication channel together with the mobile phone. Before transmitting radio waves on the communication channel, check the availability status again for reconfirmation. Once availability is confirmed, the mobile phone sends a channel switching completion signal on the call channel, and upon receiving this, the connecting device sends a channel switch confirmation signal to the mobile phone to establish a call channel loop and begin call processing. be done.

Although the above example deals with incoming calls, the same applies to outgoing calls.

As another embodiment of the present invention, in the case of an incoming call as in FIG. 4, a calling signal is sent from the connecting device, but unlike the above, free channel information is not carried here (not shown). Upon receiving this, the mobile telephone sets a plurality of vacant channels, for example, 3 to 5, which it has searched in advance, on a call response signal and sends it to the connecting device.

The connecting device that receives this checks whether it matches the available channel information that it has searched for in advance. If there is a matching channel in both pieces of information, the connecting device selects one and sends it to the mobile phone.

Upon receiving this, the mobile phone and the connected device switch the frequency used from the control channel to the designated communication channel. Follow the same steps as above to connect.

In another embodiment of the present invention, the mobile phone side does not preliminarily search for free call channels, but instead checks information on a plurality of free channels sent from the connecting device one by one, and selects the confirmed free call channels. This is used to designate an empty channel to the connected device along with the call response signal.

Generally 1! Mobile phones operate their receivers intermittently to save battery power during standby. It is a good idea to search for an empty channel when this receiver is activated. For mobile phones that do not perform battery saving, these operations are performed in the same manner as for connected devices.

Although the above describes a cordless telephone, the present invention
It is applicable to general multi-channel access method wireless communication.

In the embodiment of FIG. 1 of the present invention, the connecting device may be connected directly to the general telephone network, but it goes without saying that it will operate in the same way via a private branch exchange.

(5) Effects of the Invention According to the present invention, it is possible to reduce the probability that connection will not be possible in the worst case. Furthermore, since the number of redos required for connection can be reduced, the drawback of connection taking a long time has been improved.

In addition, because the control channel is no longer occupied for a long time due to redoing, the problem of other systems becoming unusable is reduced.

[Brief explanation of drawings]

Fig. 1 is a diagram showing a block diagram of a wireless communication system consisting of a connection device and a mobile phone to explain the present invention and a conventional example, and Fig. 2 shows a case where a connection is successfully established using the procedure of setting up a wireless line in the conventional example. FIG. 3 is a flowchart showing how a connection error occurs in the conventional wireless line setting procedure and reconnection is performed, and FIG. 4 is a diagram showing an example of the wireless line setting procedure of the present invention. Patent applicant: Iwasaki Tsushinki Co., Ltd. Tokyo Electric Power Company, Inc.

Claims (1)

[Claims] (1) A multi-channel access wireless communication system comprising at least one mobile phone and a connection device that is directly or indirectly connected to a general telephone network and can communicate well with the mobile phone, the mobile phone and the The connecting device detects an empty channel, and before connecting the wireless line, it sends information on a plurality of empty communication channels based on the detection results on the wireless control channel, and selects the available channel between the mobile phone and the connecting device. The party receiving the call channel information compares the free call channel data with the free call channel data based on the detection result, and selects the matched free call channel data from among the mobile phone and the connecting device according to a predetermined procedure. A wireless communication channel setting method characterized in that the wireless communication channel is configured to be designated and transmitted to the other party.