JPH0548530A - Idle channel search system in cordless telephone system - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a method for searching for an empty channel capable of ensuring good communication between a plurality of wireless communication units RF1 to n and a plurality of mobile stations 1 to m. In a free channel search method of a cordless telephone device including a base station including a plurality of radio communication units RF1 to n and a plurality of mobile stations 1 to m, a base station is provided with a call channel for a call. A storage unit 15 for storing invalid channels that adversely affect
Exclude the call channel stored in 15 from the free channel search. Therefore, the call channels that are determined to be "free" by the free channel search are
It is limited to only those that are not likely to cause interference or the like with respect to the call channel during the call.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for searching a free channel in a cordless telephone device.

[0002]

2. Description of the Related Art A cordless telephone system includes a base station (base unit) and a mobile station (slave unit), which are connected by a wireless line to move between the base station and the mobile station or via the base station. Station and outside line
A call is made with the (local line).

In the communication between the base station and the mobile station of the cordless telephone device, at the start of communication, call connection request data for calling the base station from the mobile station and calling for calling the mobile station from the base station. "Control data" such as data
Is a "control channel" commonly used in the entire system
“Information data” such as voice, which is transmitted after the communication is established between the base station and the mobile station, is transmitted through the “communication channel” designated by the base station from a plurality of wireless channels.

In the cordless telephone system, two channels can be used as control channels and 87 channels can be used as communication channels.

[0005] The base station in reception standby detects the call connection request data from the mobile station while receiving the control channel and the call channel alternately and determines whether the call channel is "busy" or "idle". The judgment is repeated.
When the call connection request data from the mobile station is detected in the process of this "vacant channel search", the channel judged as "vacant" immediately before (or immediately after) is designated as the call channel, and the base station and the mobile station move. "Information data" between stations
Communication is performed.

In this cordless telephone device, as shown in FIG. 3, the base station has a plurality of radio communication units RF1 to RF.
An apparatus has been proposed which has n and is configured to be able to communicate in parallel with a plurality of mobile stations among the mobile stations 1 to m.

In this device, a base station has a station line connection terminal 2 connected to a station line, a call circuit 3 forming a call path between a mobile station and a station line, and a plurality of radio communication units RF1 to RF.
n, a control unit 4 that controls the wireless communication units RF1 to RFn, and an empty channel storage unit 5, and each of the wireless communication units RF1 to RFn includes a receiving circuit 6.
It is provided with a transmission circuit 7, an antenna 8, a radio circuit 9 for connecting the reception circuit 6 and the transmission circuit 7 to the antenna 8, and a frequency synthesizer 10 for setting reception and transmission frequencies.

On the other hand, each mobile station has a receiving circuit 16, a transmitting circuit 17, an antenna 18, a receiving circuit 16 and a transmitting circuit 17.
In addition to a communication path consisting of a wireless circuit 19 for connecting the antenna 18 to an antenna 18, a receiver 12, and a transmitter 12, a frequency synthesizer 20 for setting reception and transmission frequencies and a controller 14 are provided.

In the base station of this cordless telephone device, one wireless communication unit RF1 that is not busy is used to alternately search for an "empty channel" in the call channel and detect call connection request data from the mobile station. As described above, regarding the search for an empty channel, the search is proceeding according to the procedure of FIG.

Step 1: The control unit 4 selects a desired communication channel.

Step 2: Send a signal from the control unit 4 to the frequency synthesizer 10 to set the reception frequency of the radio communication unit RF1 to the frequency band of the selected communication channel.

Step 3; The set frequency is received by the receiving circuit 6 via the antenna 8 and the radio circuit 9, and it is determined whether the communication channel is "busy" or "vacant". If busy, move to step 5.

Step 4; the judgment in Step 3 is "vacant"
If it is, the empty channel information is stored in the empty channel storage unit 5.

Step 5: The next call channel is selected, and the process returns to Step 2 to determine the free state.

In this way, the idle states of all the call channels are repeatedly determined in order, and the communication between the wireless communication unit of the base station and the mobile station is started using the "empty" call channels. It Therefore, even when communication is performed between the plurality of wireless communication units of the base station and the plurality of mobile stations, different communication channels are used respectively.

[0016]

However, in such a conventional free channel search method, it is determined only whether or not the communication channel is "free", and if it is a free channel, all of them are used for communication. Since it is a candidate for a call channel to be used, the call channels that interfere with each other are used by chance when communicating in parallel between a plurality of wireless communication units of a base station and a plurality of mobile stations. In that case, there is a case in which communication is noisy and a good call cannot be secured.

In such a case, there is an example of switching to another channel to avoid interference, but such an operation is troublesome.

The present invention solves such a problem, and provides a free channel search method capable of ensuring good communication between a plurality of wireless communication units and a plurality of mobile stations.

[0019]

Therefore, in the present invention, the storage means of the base station in the empty channel search system in the cordless telephone apparatus including the base station including the plurality of wireless communication units and the plurality of mobile stations. In this case, an invalid channel that adversely affects the communication of the call channel in use is stored, and the stored invalid channel is excluded from the target of the empty channel search.

[0020]

Therefore, the call channels determined to be "vacant" by the idle channel search are limited to those that are not likely to cause interference or the like with respect to the active call channel.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION A cordless telephone apparatus for carrying out the channel search method of the present invention, as shown in FIG. 1, is provided with an invalid channel storage section 15 in a base station. It's different.

The term "ineffective channel" as used herein refers to a channel in which when the channel is used for communication between a base station and a mobile station, the communication itself or a communication during another call causes a trouble such as interference. I mean.

Since the channels causing interference with each other can be mechanically obtained by calculation, in order to store the invalid channels in the invalid channel storage unit 15,
For example, in the process of searching for a free channel, the information of the call channel determined to be “busy” is stored in the invalid channel storage section.
It is possible to input to 15 and calculate the channel that causes interference with the call channel, store it as an invalid channel, and update the memory when the busy channel changes to "vacant" ..

A procedure for searching for an empty channel in the search method of the present invention will be described with reference to the flowchart shown in FIG.

Step 1: The control section selects a desired communication channel.

Step 2: Compare the selected call channel with the invalid channel stored in the invalid channel storage unit 15. If they match, the channel is considered invalid, and the process proceeds to step 6 to select the next communication channel.

Step 3; In Step 2, if the selected communication channel does not match the invalid channel,
A signal is sent from the control unit 4 to the frequency synthesizer 10, and the reception frequency of the wireless communication unit RF1 is set to the frequency band of the selected communication channel.

Step 4; The set frequency band is received by the receiving circuit 6 via the antenna 8 and the radio circuit 9,
It is determined whether the call channel is “busy” or “vacant”. If you are busy, move to step 6,
Select the next channel.

Step 5; The judgment in Step 4 is "vacant"
If it is, the empty channel information is stored in the empty channel storage unit 5.

Step 6; The next call channel is selected, and the process returns to Step 2 to determine the free state.

Therefore, according to the empty channel search method of the present invention, for the selected communication channel,
Before setting the vacancy judgment, it is judged whether it is an invalid channel, if it is an invalid channel, the next call channel is selected, and if the selected call channel is not an invalid channel The set is done.

[0032]

As is apparent from the above description of the embodiments, in the empty channel search system of the present invention,
Channels that adversely affect communication such as communication by the call channel in use are not selected as idle channels, so multiple communication can be performed in parallel between multiple wireless communication units of the base station and multiple mobile stations. Even if it is done, there is no risk of trouble such as interference.

[Brief description of drawings]

FIG. 1 is a block diagram of a cordless telephone device that implements a free channel search system of the present invention;

FIG. 2 is a flow chart showing the procedure of an empty channel search system of the present invention

FIG. 3 is a block diagram showing an example of a conventional cordless telephone device.

FIG. 4 is a flowchart showing a procedure of a conventional free channel search method.

[Explanation of symbols]

 RF1 to n Wireless communication unit 1 to m Mobile station 2 Station line connection terminal 3 Call circuit 4, 14 Control unit 5 Free channel storage unit 15 Invalid channel storage unit 6, 16 Reception circuit 7, 17 Transmission circuit 8, 18 Antenna 9, 19 Radio circuit 10, 20 Frequency synthesizer 12 Handset 13 Handset

Claims (1)

[Claims] 1. A vacant channel search method in a cordless telephone apparatus comprising a base station having a plurality of wireless communication units and a plurality of mobile stations, wherein the storage means of the base station stores the communication channel in use. An empty channel search method in a cordless telephone device, characterized in that an invalid channel that adversely affects communication is stored and the stored invalid channel is excluded from an object of free channel search.