JP2923195B2 - Digital cordless telephone - Google Patents

Abstract

PURPOSE:To speedily and surely execute a transmission channel (TCH) switching operation by detecting speaking quality degradation or level degradation during direct inter-slave set speaking and transmitting a TCH switching request message plural times as needed. CONSTITUTION:When a detection part 9 for detecting the speaking quality degradation or the level degradation detects the speaking quality degradation or the level degradation caused by telephone interference during the direct inter-slave set speaking and detects the state of reception from an opposite side mobile station (PS), a TCH switching request message transmission part 10 transmits the TCH switching request message for requesting TCH switching to the opposite side PS plural times if necessary Thus, since the TCH switching request message is transmitted plural times until a transmitted signal from the opposite side PS is stopped, the TCH switching operation can be speedily and surely executed by improving probability for the TCH switching request message to reach the opposite side PS.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a mobile station (PS: Personal Station) registered in the same private base station (CS) without passing through the private base station (CS). The present invention relates to a digital cordless telephone having a direct call function between child devices capable of making a direct call.

[0002]

2. Description of the Related Art According to a standard (draft) of a second generation cordless telephone system which is currently under study, this second generation cordless telephone system is such that mobile stations registered in the same private base station can communicate with each other. And a direct communication function between the slave units, which allows a direct communication without passing through the private base station. The outline of the operation of direct communication between slave units described in the second generation cordless telephone system standard (draft) will be described below. In addition, mobile stations can communicate with each other by the direct communication function between handset units, which are registered in the same private base station, that is, only mobile stations with the same system call code recognized by the mobile station. I have.

FIG. 3 is an explanatory diagram of a control sequence of direct communication between slave units described in the second generation cordless telephone system standard (draft). Based on FIG. 3, the second generation cordless telephone system standard The communication method and communication channel (T
CH) switching method is described below. In FIG. 3, an originating mobile station (a mobile station that calls a partner mobile station to perform a direct communication between slave units, hereinafter referred to as an originating PS) is used to detect an empty slot of a carrier for direct communication between slave units. After performing carrier sense defined by this standard (draft) and confirming that the carrier is usable (empty), a call signal a is transmitted to the other party of the carrier who wants to talk at the slot timing. On the other hand, the receiving side mobile station (a mobile station receiving a call from another mobile station, hereinafter called a receiving side PS) sequentially searches for a carrier for direct communication between slave units in a call waiting state for direct communication between slave units. In this way, a search is made to see if a calling signal to the own station has been transmitted, and after receiving a calling signal a containing the PS calling number of the own station, a synchronizing signal b is transmitted to the originating PS by a calling signal reception. The transmission is performed at a slot timing after 0.5 ms. Thereafter, the transmitting side PS receiving the synchronization signal b from the receiving side PS transmits the synchronization signal c, and the receiving side PS receiving the synchronization signal c from the transmitting side PS.
Transmits a response signal d when the user presses a response button, and thereafter exchanges TCH idle burst signals e and f to perform a call operation.

[0004] Here, (1) When the transmitting side PS detects the degradation of the communication quality or the level deterioration due to radio wave interference or the like, the transmitting side PS transmits a TCH switching request to the receiving side PS, and then performs the TCH switching. Carrier sense is performed to find a channel (switching destination channel) for transmitting a synchronization signal for the TCH, and a synchronization signal for TCH switching is transmitted to the receiving side PS in an available slot. The receiving PS receiving the TCH switching request from the calling PS performs a search operation while switching the frequency in order to search for a synchronization signal for TCH switching for its own station. After receiving the synchronization signal for switching the TCH from the transmission side PS, the receiving side PS transmits a synchronization signal for switching the TCH to the transmission side PS, and enters the talking state.

[0005] After receiving the synchronization signal for switching the TCH from the receiving side PS, the calling side PS enters a talking state.

[0006] (2) When the receiving side PS detects a deterioration in speech quality or level deterioration due to radio wave interference or the like, the receiving side PS transmits a TCH switching request to the calling side PS, and then transmits a TCH switching request to its own station. In order to search for a synchronization signal for switching, a search operation is performed while switching the frequency. TCH from the receiving PS
The transmitting side PS that has received the switching request performs carrier sense to find a channel (switching destination channel) for transmitting a synchronization signal for TCH switching, and performs TCH switching for the receiving side PS in an available slot. To send a synchronization signal. After receiving the synchronization signal for switching the TCH from the calling side PS, the called side PS sends a T
A synchronization signal for CH switching is transmitted, and a call state is established.

[0007] After the transmission side PS receives the synchronization signal for switching the TCH from the reception side PS, the transmission side PS enters the talking state.

[0008]

However, according to the communication method and the communication channel (TCH) switching method described above, during direct communication between the slave units, (1) the calling side PS deteriorates in communication quality due to radio wave interference or the like;
Alternatively, when the level degradation is detected, a TCH switching request message is transmitted once to the receiving side PS, and then carrier sense is performed to immediately find a switching destination channel. To transmit a synchronization signal for TCH switching. Calling side P with receiving side PS
If a TCH switching request message from S cannot be received, communication is attempted to be continued on the used channel. After that, the receiving PS cannot receive the transmission from the calling PS and transmits the TCH switching request by itself to perform the TCH switching operation. Therefore, the TCH switching request is first received from the calling PS, and then the TCH switching is actually performed. Sometimes it took time to do that. In addition, (2) the receiving side PS deteriorates in call quality due to radio wave interference,
Alternatively, when the level deterioration is detected, a TCH switching request message is transmitted once to the transmitting side PS, and then a synchronization signal for TCH switching for the own station is immediately searched.
If the transmitting PS cannot receive the TCH switching request message from the receiving PS, it tries to continue the communication on the used channel. After that, the transmitting PS cannot receive the transmission from the receiving PS, and transmits a TCH switching request by itself and
To perform the CH switching operation, first, the receiving side PS issues a TCH
In some cases, it takes time from receiving the switching request to actually performing the TCH switching. There is a possibility that such a problem may occur. SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a digital cordless telephone that does not cause the above problems.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problem, the present invention provides a method for directly communicating between mobile stations registered in the same private base station without passing through the private base station. A digital cordless telephone having a direct communication function between slave units, comprising: a detecting unit for detecting a call quality deterioration or a level deterioration due to radio wave interference or the like during the direct communication between the slave units; A transmission unit that transmits a communication channel switching request message for requesting the other mobile station to switch the communication channel a plurality of times when the quality deterioration or the level deterioration is detected is provided. The communication channel switching request message is transmitted a plurality of times upon detecting the deterioration, and the transmission of the communication channel switching request message is performed by the other party. Transmission signal from the one in which is no to continue to cease.

[0010]

In the above configuration, when the communication quality deterioration / level deterioration detection unit detects the communication quality deterioration or level deterioration due to radio wave interference or the like during the direct communication between the slave units and detects the reception state from the partner mobile station, the communication is started. A channel switching request message transmitting unit transmits a TCH switching request message for requesting a communication channel (TCH) switching to a partner mobile station a plurality of times, if necessary. By transmitting the switching request message a plurality of times in this manner, the probability that the TCH switching request message reaches the partner PS is increased, and the TCH switching operation can be performed quickly and reliably. Further, once the TCH switching request is transmitted, the TCH switching request is continued until the transmission signal from the partner mobile station stops on the busy channel.
By transmitting the switching request message a plurality of times, TC
The probability that the H switching request message reaches the partner PS can be increased, and the TCH switching operation can be performed quickly and reliably.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a configuration diagram of a mobile station of a digital cordless telephone according to the present invention. FIG. 2 is an explanatory diagram of a control sequence relating to switching of a communication channel (TCH) for direct communication between slave units in the digital cordless telephone of the present invention. In FIG. 1, 1 is an antenna for exchanging signals with a private base station, a partner mobile station, etc., 2 is a radio section, 3 is a modulation / demodulation section, 4 is a channel codec section, 5 is a control section, and 6 is voice processing. A microphone 7; an ear speaker 8; a detection unit 9 for detecting a deterioration in communication quality or level deterioration due to radio wave interference or the like during direct communication between slave units; A transmission unit that transmits a communication channel switching request message for requesting the partner mobile station to switch the communication channel a plurality of times upon detecting the level deterioration.

Next, a control sequence relating to switching of a communication channel (TCH) for direct communication between slave units in the digital cordless telephone having the above configuration will be described with reference to FIG.

The sequence until the mobile station detects interference in the control sequence of FIG. 2 is the same as that of the conventional example described with reference to FIG. 3, and a description thereof until the mobile station detects interference will be omitted.

First, (1) a calling mobile station (hereinafter referred to as a calling PS) during a call.
If the transmission side PS detects degradation of communication quality or level due to radio wave interference or the like, the transmitting side PS continues to transmit the TCH switching request g to the receiving side mobile station (hereinafter called the receiving side PS). When the transmission signal from the receiving side PS is not received in the busy channel, it is determined that the TCH switching request has reached the receiving side PS, the transmission of the TCH switching request is stopped, and the synchronization signal for the TCH switching is transmitted. Carrier sense is performed to find a channel to transmit. According to the carrier sense result, if available, a synchronization signal h for TCH switching is transmitted to the receiving side PS in an available slot of that frequency. TCH switching request g from originating PS
The receiving PS searches for a synchronization signal for switching its TCH to its own station. The receiving side PS has T for its own station.
After receiving the synchronization signal h for CH switching, the transmitting side PS
, A synchronization signal i for switching TCH is transmitted, and the communication state is established. After receiving the synchronization signal i for TCH switching from the receiving side PS, the calling side PS enters the talking state.

[0015] (2) During communication, if the receiving-side PS detects a deterioration in call quality or level deterioration due to radio wave interference or the like, the receiving-side PS
Keeps transmitting the TCH switching request to the originating PS.
When the transmission signal from the calling side PS is no longer received on the busy channel, the TCH switching request is issued by the calling side PS.
, The transmission of the TCH switching request is stopped,
A search is performed to find a channel for transmitting a synchronization signal for CH switching. The transmitting side PS receiving the TCH switching request from the receiving side PS performs carrier sense in order to find a channel for transmitting a synchronization signal for TCH switching.

According to the result of the carrier sense, if the frequency can be used, a synchronization signal for switching the TCH is transmitted to the receiving side PS in the available slot of the frequency. After receiving the synchronization signal for switching the TCH from the transmission side PS, the receiving side PS transmits a synchronization signal for switching the TCH to the transmission side PS and enters the talking state.

After the transmitting PS receives the synchronization signal for switching the TCH from the receiving PS, the calling PS enters a talking state.

As described above, in the digital cordless telephone having the above-described configuration, the detecting unit 9 for detecting the deterioration of the communication quality or the deterioration of the level detects the deterioration of the communication quality or the deterioration of the level due to radio wave interference during the direct communication between the slave units. When the communication channel switching request message sending unit 10 detects a receiving state from the partner PS, the communication channel switching request message sending unit 10 transmits a T
A CH switching request message is transmitted a plurality of times. By transmitting the switching request message a plurality of times as described above, the TC
By increasing the probability that the H switching request message reaches the partner PS, the TCH switching operation can be performed quickly and reliably. Further, once the TCH switching request is transmitted, the TCH switching request message is transmitted a plurality of times until the transmission signal from the partner PS stops on the busy channel, so that the probability that the TCH switching request message will reach the partner PS is increased. And the TCH switching operation can be performed quickly and reliably.

[0019]

According to the present invention, a mobile station registered in the same private base station has a direct telephone communication function between slave units, which enables a direct telephone call without passing through the private base station. In a digital cordless telephone, when a mobile station detects a call quality deterioration or a level deterioration due to radio wave interference or the like during a direct call between slave units, it switches a communication channel (TCH) to a partner mobile station if necessary. By transmitting the TCH switching request message for request a plurality of times, the probability that the TCH switching request message reaches the partner mobile station is increased, and the TCH switching operation can be performed quickly and reliably.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a mobile station of a digital cordless telephone according to the present invention.

FIG. 2 is an explanatory diagram of a control sequence related to switching of a communication channel (TCH) for direct communication between slave units in the digital cordless telephone of the present invention.

FIG. 3 is an explanatory diagram of a control sequence of direct communication between slave units, which is described in a second generation cordless telephone system standard (draft).

[Explanation of symbols]

 9 Communication quality deterioration / level deterioration detection unit 10 Communication channel switching request message sending unit

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04B 7/24-7/26 102 H04Q 7/00-7/38 H04M 1/00

Claims (2)

(57) [Claims] 1. A digital cordless telephone having a direct communication function between mobile units, which enables mobile stations registered in the same private base station to directly communicate with each other without passing through the private base station. The mobile station receives a plurality of communication channel switching request messages for requesting the partner mobile station to switch communication channels, and a detection unit for detecting communication quality deterioration or level deterioration due to radio wave interference or the like during direct communication between slave units. A digital cordless telephone, comprising: a transmitting unit that transmits a communication channel switching request message a plurality of times by detecting a deterioration in communication quality or a level deterioration during a direct telephone call between slave units. 2. The digital cordless telephone according to claim 1, wherein the transmitting unit continues to transmit the communication channel switching request message until the transmission signal from the partner mobile station stops.