JP2821308B2 - Voice transmission system in mobile communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication system having a control channel and a voice channel for connecting a radio line between a mobile station and a base station, and more particularly to a voice transmission system.

[0002]

2. Description of the Related Art Conventionally, in a voice transmission system in a mobile communication system having a control channel and a voice channel for connecting a radio line between a mobile station and a base station, a control channel is a control signal such as an outgoing call or incoming call. Used only for transmission of
Audio was transmitted only through the audio channel.

[0003] In such a system, broadcast is performed by dialing a specific number different from an individual call. FIG. 7 shows the procedure of a conventional broadcast communication, which will be described below. The control station receiving the broadcast request specifies a voice channel to be used for the broadcast to the base station and the mobile station. The base station and the mobile station that have received the voice channel change channels to the specified voice channel. After a certain period of time, the base station forces the mobile station to go off-hook and reports this to the control station. When the control station confirms that the mobile station has been off-hook, it starts broadcasting.

[0004]

In the above-mentioned conventional system, since the voice is transmitted only through the voice channel, when the broadcast is performed, all the mobile stations have the voice channel regardless of their own will. Is switched to the busy state, so that calling and receiving cannot be performed.

[0005]

A voice transmission system in a mobile communication system according to the present invention is a mobile communication system having a control channel and a voice channel for connecting a radio line between a mobile station and a base station. The station comprises coding means for coding a voice signal, and multiplexing means for time-division multiplexing the voice signal coded by the coding means onto a control channel, wherein the mobile station is time-division multiplexed. Separating means for separating the signal on the control channel into an encoded audio signal part and a control signal part; decoding means for decoding the audio signal part separated by the separating means into audible sound; Selection means for selecting either to continue receiving voice in the channel or to perform the incoming call processing.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIGS. 1A and 1B are system configuration diagrams showing one embodiment of the present invention. FIG. 2 is a diagram showing an example of a frame format of a control signal and an audio signal transmitted on a control channel. FIG. 3 is a diagram showing an example of a multiplexed state of a control signal frame and an audio signal frame on a control channel. FIGS. 4 and 5 are diagrams showing a procedure for receiving an incoming call during a broadcast. FIG. 4 shows a procedure for switching to an individual call, and FIG. 5 shows a procedure for continuing the broadcast. It is shown. FIG. 6 is a diagram showing a procedure for making a call during simultaneous broadcast communication.

In FIG. 1A, a control station 3 transmits a control signal and a voice signal to and from a mobile station 1 via a base station 2.
Transmission and reception are performed using the control channel and the voice channel. The base station 2 includes a control channel transmitter 5, a control channel receiver 6, an audio channel transmitter 7, an audio channel receiver 8, a multiplexing device 9, an encoding device 10, a remote processor 11, an antenna 4 is provided. The control link between the control station 3 and the base station 2 is a common channel signal control device 1
4 is connected to the remote processor 11 and the control station 3
Controls the entire mobile communication system. Also,
The control signals between the control station 3 and the mobile station 1 are transmitted to a remote processor 11, a control channel transmitter 5, a control channel receiver 6
And mobile station 1 via a control channel through antenna 4
Connected to The voice signal between the control station 3 and the mobile station 1 includes a trunk 13, a voice channel transmitter 7,
The mobile station 1 is connected to the mobile station 1 through the voice channel through the voice channel receiver 8 and the antenna 4, and is connected to the trunk 12, the encoding device 10, the multiplexing device 9, the control channel transmitter 5 and the antenna 4 at the time of broadcast. Connected to the mobile station 1 via the control channel.

In FIG. 1B, the mobile station 1 has an antenna 1
5, a receiver 16, a switching circuit 17, and a separation circuit 18
, A control circuit 19, a decoding circuit 21, and an audio circuit 20
And a speaker 22. In the mobile station 1, a control signal is connected to a control circuit 19 through an antenna 15, a receiver 16, a switching circuit 17 and a separation circuit 18, and the mobile station 1 is controlled by the control circuit 19. Mobile station 1
The audio signal connected via the audio channel is passed through the antenna 15, the receiver 16, the switching circuit 17 and the audio circuit 20, and is sent as audio from the speaker 22. The audio signal connected via the control channel is Receiver 16, switching circuit 17, separation circuit 18, decoding circuit 2
1 and the audio circuit 20, and is sent as audio from the speaker 22.

[0010] When multiplexing voice to the control channel in such a system, the voice is input to the encoding device 10 via the trunk 12. The encoding device 10 encodes the above-mentioned audio signal and inputs it to the multiplexing device 9. A control signal from the common line signal control device 14 is input to the multiplexer 9 via the remote processor 11. The multiplexing device 9 time-division multiplexes the voice signal input from the encoding device 10 and the control signal input from the remote processor 11, and multiplexes this signal via the control channel transmitter 5 using the control channel to the mobile station. Send to 1.

Next, an embodiment of a method for multiplexing a control signal and a voice signal will be described. In this example, the control signal and the audio signal are each composed of a frame, and an identification signal indicating whether the frame is the audio signal frame 24 or the control signal frame 23 is added.

The speech is encoded and then converted into a frame to form a speech signal frame 24. The control signal is a control signal frame 23 obtained by adding an identification signal to a conventional frame. In the case of transmitting voice, the voice signal frame 24 is placed on the control channel at intervals that do not cause inconvenience when decoding the voice signal frame 24 at the mobile station.
A control signal frame 23 is placed between these frames to bring the control channel 25 into a state. Therefore, when the audio signal is not transmitted, only the control signal frame 23 is carried on the control channel. This example will be described. If we decide to transmit the audio signal after compressing the bandwidth to about 8 kbps,
In a control channel with a transmission rate of about 50 kbps,
During the broadcast, an audio signal frame 24 must be loaded for every six frames in order to transmit the audio correctly. For this reason, the signal amount of the control signal on the control channel is reduced by about 1/6, but the influence is negligible considering the importance of the broadcast and the small traffic amount.

On the other hand, the mobile station 1 waiting on the control channel
Inputs the signal on the control channel to the separation circuit 18 via the antenna 15, the receiver 16, and the switching circuit 17. The separation circuit 18 converts the received signal into an audio signal frame 24.
And a control signal frame 23. The audio signal is input to the audio circuit 20 after being decoded by the decoding circuit 21, and the control signal is input to the control circuit 19. The audio circuit 20 converts the input audio signal into an audible sound and outputs it from the speaker 22. The control circuit 19 controls the mobile station 1 according to the input control signal.

An embodiment of a method for separating a control signal and a voice signal will be described. The separation is performed on frames 23 and 2 on the control channel.
4 is performed by the separation circuit 18 determining whether the frame is the audio signal frame 24 or the control signal frame 23 based on the frame identification signal.

Next, a description will be given of an embodiment of a procedure for calling and receiving calls during simultaneous broadcast communication. First, an incoming call procedure will be described with reference to FIGS. Upon receiving the call request, the control station calls the mobile station via the base station using a control signal on a control channel. At this time, the control signal and the audio signal are on the control channel. The mobile station receiving the call makes a call response to the control station via the base station. The control station that receives the call response specifies the voice channel to be used for the individual call to the base station and the mobile station. The base station and the mobile station that have received the voice channel change channels to the specified voice channel. Upon confirming the carrier from the mobile station on the designated voice channel, the base station instructs the mobile station to ring. When the mobile station receives the ringing start request, it rings the ringing tone, reports the ringing to the control station via the base station, and returns the ringing tone to the calling subscriber.

At this time, the subscriber of the mobile station selects whether to continue the broadcast communication or to receive a call. When a subscriber of a mobile station chooses to receive an incoming call, the mobile station is placed off-hook. The off-hook mobile station reports off-hook to the control station via the base station. When the control station confirms that the mobile station has gone off-hook, the control station starts a call between the mobile station and the calling subscriber.

When the subscriber of the mobile station selects the continuation of the broadcast, the mobile station changes the channel to the control channel and returns to the broadcast. Due to the channel change of the mobile station, the base station cannot detect the carrier of the mobile station on the designated voice channel, and reports this to the control station. The control station that has confirmed that the carrier of the mobile station cannot be detected makes the voice channel designated to the base station idle. As a result, the base station makes the designated voice channel idle.

The procedure for making a call will be described with reference to FIG. When a mobile station makes a call, it sends a dial number to the control station via the base station in accordance with information obtained from a control signal on the control channel, and makes a call. Upon receiving this, the control station performs the switching operation and designates a voice channel to be used for the individual call to the base station and the mobile station. The mobile stations which have received the voice channel designation change the channel to the designated voice channel. When the base station confirms the carrier from the mobile station on the designated voice channel, it reports to the control station that the line has been secured. The control station that receives a ringing tone from the called subscriber by the switching operation sends the ringing tone to the mobile station via the base station via a voice channel. After this,
The call between the mobile station and the called subscriber is started when the called subscriber answers.

[0019]

As described above, according to the present invention, by placing a voice on a control channel, a voice can be transmitted to a mobile station waiting on the control channel without imposing restrictions on outgoing and incoming calls. There is an effect that can be transmitted.

[Brief description of the drawings]

FIG. 1A is a system configuration diagram showing an embodiment of the present invention. (B) is a diagram showing the configuration of the mobile station in (a).

FIG. 2 is a diagram illustrating an example of a frame format of a control signal and an audio signal transmitted on a control channel.

FIG. 3 is a diagram illustrating an example of a multiplexed state of a control signal frame and an audio signal frame on a control channel.

FIG. 4 is a diagram showing a procedure for receiving an incoming call during simultaneous broadcast communication and switching to an individual call.

FIG. 5 is a diagram showing a procedure for receiving an incoming call during the broadcast and continuing the broadcast.

FIG. 6 is a diagram showing a procedure for making a call during simultaneous broadcast communication.

FIG. 7 is a diagram showing a procedure of a conventional simultaneous broadcast communication.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mobile station 2 Base station 3 Control station 4, 15 Antenna 5 Control channel transmitter 6 Control channel receiver 7 Voice channel transmitter 8 Voice channel receiver 9 Multiplexer 10 Encoder 11 Remote processor 12, 13 Trunk 14 Common Line signal controller 16 Receiver 17 Switching circuit 18 Separation circuit 19 Control circuit 20 Audio circuit 21 Decoding circuit 22 Speaker 23 Control signal frame 24 Audio signal frame 25 Control channel state (audio signal + control signal) 26 Control channel state (Control signal only)

Claims (1)

(57) [Claims] 1. A mobile communication system having a control channel and a voice channel for connecting a radio channel between a mobile station and a base station, wherein the base station includes a coding unit for coding a voice signal, and a coding unit for coding the voice signal. Multiplexing means for time-division multiplexing the audio signal encoded by the means onto a control channel, wherein the mobile station comprises: an audio signal portion encoded by encoding the signal on the time-division multiplexed control channel; and a control signal. Separation means for separating the audio signal into two parts, a decoding means for decoding the audio signal part separated by the separation means into an audible sound, and whether to continue receiving the voice on the control channel or to perform the incoming call processing. Selecting means for selecting any one of the following: a voice transmission system in a mobile communication system.