JPS5829018B2 - Simultaneous transmission and reception mobile radio system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mobile radio system that further improves serviceability by enabling simultaneous transmission and reception of a control channel and a communication channel using one radio device.

In the mobile radio system, a specific radio channel is selectively acquired from among a large number of radio channels, and a communication channel is set so that a large number of mobile radio devices can communicate without colliding with each other.

In order to efficiently use a large number of radio channels and avoid call collisions as much as possible, several control channels are provided for uplink and downlink.

An example is shown in FIG.
)), access channel AI as a call control channel
(A'l), A2 (A'2), (frequency f
a1(f'a1), fa2(r'3□)).

Conventionally, mobile radio equipment captures one radio channel for transmitting and one for receiving, so during a call, the control channel (P in Figure 1)
There are problems such as the inability to receive information on channels (Channel, A channel), which complicates the control of channel switching during calls, resulting in instantaneous interruptions of calls, and the inability to perform detailed control or receive notification signals during calls. Ta.

In addition, when there are multiple callers and a call waiting service is provided, such as with a fixed-line button telephone, when transmitting a single wireless channel that has a lot of fading, hook signals are transmitted during calls, etc. This type of stable service was not available due to difficulties.

Furthermore, in order to simultaneously receive a plurality of channels using the conventional technology, a plurality of systems of expensive radio units are required, which is difficult to realize from an economical point of view.

For example, a typical example of a conventional mobile radio device is shown in FIG.
This allows only one channel band to pass.

The intermediate frequency received signal that has passed through the filter is sent to an amplifier 5,
The demodulator 6 converts the signal into an audio/data signal, which passes through the control section 7 and is received by the telephone 11.

On the other hand, the transmission signal is converted into a carrier wave modulated signal by the modulator 10, converted into a radio frequency signal by the transmission mixer 9, and transmitted by the antenna 1 via the duplexer 2.

Here, the synthesizer 8 is automatically or manually set to a predetermined frequency so that the P channel can be received before a call is made.

To carry out the call procedure, the synthesizer 8 is then shifted in frequency so that it can transmit and receive over one of the A channels, away from the P channel.

When the communication procedure is completed, the frequency of the synthesizer 8 is shifted so that the synthesizer can transmit and receive one of the S channels (Si and 81' form a transmitting/receiving pair), and is separated from the A channel.

In this way, conventional mobile devices transmit the control channel (P channel or A channel) at the same time as the busy channel (S channel).
However, in order to have such a function, it was necessary to have at least one system of radio equipment with a configuration substantially the same as that shown in FIG. 2.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to provide a simple and economical simultaneous transmitting/receiving mobile radio system that is capable of transmitting and receiving control channels even during a call. There is a particular thing.

The details of the present invention will be explained below with reference to the drawings.

FIG. 3 is a block diagram showing an example of the configuration of a mobile radio device used in an embodiment of the present invention.

In the figure, an antenna 1, a duplexer 2, a receive mixer 3, a transmitter mixer 9, and a telephone 11 are the same as those in the conventional example shown in FIG. 21 is used.

That is, the received intermediate frequency signal, which is the output of the receiving mixer 3, is amplified by a wide range intermediate frequency amplifier 20, and then converted into a digital signal by an analog-to-digital converter (hereinafter referred to as an A/D converter) 22.

This signal is processed for channel selection,
Bandwidth limitation and demodulation are applied to the digital
Analog converter 26 (hereinafter referred to as D/A) converter 2
6) is converted into an audio signal by the telephone 1.
1 of the handset is activated.

On the other hand, the audio signal from the transmitter of the telephone 11 is
The signal is converted into a digital signal by the A/D converter 27, subjected to predetermined processing such as band limiting and modulation by the processing circuit 24 and memory 25, and converted to a carrier wave signal by the D/A converter 23.

This signal is further converted into a radio frequency signal by a transmission mixer 9 and a local oscillator 21, and a modulated analog signal is transmitted via a duplexer 2 and an antenna 1 as in the case of FIG.

On the other hand, when receiving a control channel signal, the digital signal that is the output of the A/D converter 22 is first sent to the processing circuit 22.
4, demodulates, identifies and decodes the control channel signals necessary for telephone operation and notification such as tone signals to the voice channel and the channel selection means and D/A converter 2.
6 to the telephone 11.

FIG. 4 is a block diagram showing an example of the configuration of the processing circuit 24, but each block may be an individual circuit, or may function in a time-sharing manner using one arithmetic function circuit (processor). good.

31 is a band-pass filter based on digital signal processing, and the parameter that determines its center frequency is controlled by a filter control unit 34.
Both the control channel and communication channel are changed in a time-sharing manner.

The demodulation/identification section 32 outputs the control channel signal to the calculation section 35 and the audio signal to the switching section 33 based on the identification result of the demodulated signal.

The switching section 33 converts control channel signals such as tone signals from the calculation section 35 and audio signals from the demodulation/identification section 32 into D.
/A converter 26.

The transmission switching unit 36 transfers control signals such as dial signals to the calculation unit 3.
5 and connects the audio signal to the modulation section 37.

The transmission control signal from the calculation section 35 is transmitted to the modulation section 3T via the switching section 36.

The modulated transmission control signal is subjected to appropriate band limitation and center frequency selection, that is, channel selection, in the channel selection section 38 and is guided to the D/A converter 23.

In this way, the mobile radio device used in the method of the present invention has 1
The control channel and communication channel can be transmitted and received simultaneously on a time-division basis.

In other words, to explain the receiving side again, filter 3
The control unit 34, which controls parameters for determining the center frequency of one passband, transmits the parameters to the filter 31 in a time-division manner, thereby allowing this mobile radio device to alternately receive two channels.

For example, the time period at which the band-pass filter 31 passes a specific audio channel may be equal to or less than 7 of the reciprocal 1/BM of the modulation frequency band BM.

In this case, the calculation repetition period of the band-pass filter 31 based on digital signal processing may be 7.1 or less, assuming that the receiving bandwidth 1 is BR, as shown in FIG.

Figure 5 shows the P channel (frequency f,) and the 81 channel (frequency f).
This is an example of a case where frequencies f1) are received alternately.

FIG. 6 is an example of time domain display in this case.

In this way, the conditions shown above, i.e. 1 213,,<2□.

Therefore, the control signal channel signal can be received without causing any distortion to the audio.

For example, when switching wireless zones during a call, conventionally the control channel signals related to the procedure were sent and received on the call channel, so the call had to be interrupted momentarily, but with the method of the present invention, the above-mentioned By using a mobile radio and adding means to the base station for transmitting and receiving a channel switching designation signal on a control channel (P channel or A channel), it is possible to switch channels during a call without interrupting the call.

According to the present invention, since the P channel is received even during a call, if another call arrives during a call, the data can be decoded by the calculation unit 35.

Therefore, by sending a specific tone to the telephone set via the D/A converter 22, it is possible to notify the caller that there is an incoming call, thereby keeping the previous caller waiting and communicating with the new caller. Calls can be made using the same S channel or other S channels.

That is, a so-called call waiting service can be provided.

According to the present invention, since the call control channel and the call channel are simultaneously received, the notification signal can be received via the control channel even during the call.

Furthermore, according to the method of the present invention, it is possible to monitor and control calls in detail even during a call. For example, when traffic becomes congested, it is possible to notify call time limits, or to forcibly separate calls even within the service area. Various services can be provided, such as switching communication channels to empty channels.

As described above, the system of the present invention that simultaneously transmits and receives a communication channel and a control channel can greatly contribute to improving the controllability of mobile radio equipment and improving the serviceability of mobile radio systems.

[Brief explanation of drawings]

Figure 1 shows an example of a general channel arrangement in mobile radio.
Figure 2 shows an example of the configuration of a mobile radio device in the conventional system;
The figure shows an example of the configuration of a mobile radio device used in an embodiment of the mobile radio system of the present invention, FIG. 4 shows an example of the configuration of the digital signal processing section of FIG. 3, and FIG. FIG. 6 is a conceptual diagram illustrating reception. FIG. 6 is a conceptual diagram illustrating the frequency relationship and time relationship necessary for simultaneous reception of a control channel and a voice channel. 1...Antenna, 2...Transmitter/receiver duplexer,
3...Reception mixer, 9...Transmission mixer, 11...Telephone, 24...Digital signal processing circuit, 31...Digital signal processing Bandpass filter with variable center frequency, 32...
Demodulation/identification section, 33...Switching section, 34...
- Filter control section, 35... Calculation section, 36...
...Transmission switching section, 37...Modulation section, 38...
...Channel control section.

Claims (1)

[Claims] 1 In a mobile radio system that selects and captures a specific radio channel from among multiple radio channels to make a call, a mobile radio is equipped with a band-pass filter whose center frequency is variable by digital signal processing, and the center frequency of the band-pass filter is time-divisionally adjusted. A simultaneous transmitting/receiving mobile radio system characterized by simultaneously transmitting and receiving a control channel and a communication channel by switching between them.