JP2001177465A - Digital wireless speech system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital wireless speech system to which a conference speech is easily applicable without increasing a hardware amount and complicating control contents through the OR synthesis of digital voice signals. SOLUTION: A control station C receiving a conference speech request from a terminal 1A via an incoming control channel fud, selects incoming and outgoing speech channels fu and fd among idle speech channels, instructs the terminal 1A to use the incoming speech channel fu and make transmission via an outgoing control channel fcd, and commands terminals 2A, 3A to receive a signal through the outgoing speech channel fd. Then the control station C receives a signal sent from the terminal 1A via the incoming speech channel fu and transmits it via the outgoing speech channel fd. Since the signal of the speech channel fd is received by the terminals 2A, 3A in a group A at the same time, a conference speech using the terminal 1A for the terminal is conducted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital radio communication system including a mobile terminal, and more particularly, to a digital radio communication system in which a plurality of digital radio terminals can communicate via a control station.

[0002]

2. Description of the Related Art As is well known, in a general subscriber telephone system, basically, two subscribers make a one-to-one call. However, at this time, a so-called conference telephone, in which three or more terminals can participate in a telephone call, is conventionally known. This service is currently available in a general subscriber telephone system. Although no examples have been seen, it seems that private telephone systems are being considered for adoption.

Therefore, in recent years, even in a radio communication system including a mobile terminal shown in FIG. 9, for example, only one-to-one communication between a terminal 1 and a terminal 2 in a one-to-one communication via a control station is required. Instead, as shown in FIG. 10, a request for a conference call in which a plurality of terminals of three or more stations, for example, terminal 1 and terminal 2, and terminal 3 participate, and a call can be simultaneously made between them is heard. It has become.

Here, in the case of the individual communication system shown in FIG. 9, first, up / down channels f1u / f1d and f2u / f2d are set between the two terminals 1 and 2 and the control station, respectively. good.

However, in the case of a conference call shown in FIG.
Uplink / downlink channels f1u / f1d, f2u / f2d, f3u / between the terminals 1 to 3 in the control station and the control station, respectively.
It is not enough to set f3d individually, as shown in the figure.
Uplink channels f1u and f2 from the terminals 1 to 3 at the control station.
It is necessary to OR-combine the audio signals by u and f3u, and then to transmit the signals to the respective downstream channels f1d, f2d and f3d.

[0006]

In the above prior art, it cannot be said that the digitalization of the communication system is considered, and the amount of hardware is greatly increased when a conference call is applied, and the contents of the control are significantly complicated. There was such a problem.

For example, when a conference call is applied to a wireless communication system including a mobile terminal, as shown in FIG. 10, it is necessary to perform OR synthesis of a voice signal in a control station.
When the application target is an analog wireless communication system, as shown in FIG. 11, there is almost no problem since only superposition of analog signals, that is, addition of signal levels is sufficient.

However, in recent years, digitalization has been advanced in the field of communication processing, and the digital system has been changed to the mainstream in the radio communication system. ) Is required, which complicates the processing.

When an audio signal is converted into a digital signal and transmitted, it is common to transmit the audio signal after compression encoding. In this case, as shown in FIG. 12, audio OR synthesis is performed prior to synthesis processing. In other words, a digital compression / decoding process is required, and a digital compression / encoding process is required after the synthesis operation, which further complicates the speech synthesis process.

Therefore, in the prior art, when a conference call is applied to a digital radio communication system, the call quality is increased due to the addition of the compression encoding process and the decompression decoding process in addition to the increase in the amount of hardware and the complexity of the control contents. Various problems such as deterioration of transmission and increase of transmission delay time will occur.

It is an object of the present invention to provide a digital radio communication system in which a conference call can be easily applied without increasing the amount of hardware and complicating control contents due to OR synthesis of digital audio signals.

[0012]

SUMMARY OF THE INVENTION The object of the present invention is to provide a digital radio communication system in which at least three terminals are provided and a communication channel is set between these terminals by a control station. One of the plurality of terminals
Means for supplying audio data received on a channel allocated for transmission to one terminal to one channel commonly allocated for reception to at least two other terminals, and One terminal is a transmitting terminal,
This is achieved by using at least two other terminals as receiving terminals so that a conference call with a fixed transmitting terminal therebetween can be performed.

[0013] It is another object of the present invention to provide at least two base stations connected to a control station by respective approach lines, and a plurality of terminals coupled to each of the base stations by radio channels. In a digital radio communication system of a system for setting a communication channel of at least one of the control station and the base station, in the control station, voice data received on an approach channel of an approach line from one of the base stations is transmitted to the control station. Means for supplying a downlink channel of an approach line to at least two other stations, wherein one terminal among the plurality of terminals is a transmitting terminal, and
This is achieved by using one of the terminals as a receiving terminal so that a conference call with a fixed transmitting terminal between them can be performed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a digital radio communication system according to the present invention will be described in detail with reference to the illustrated embodiments. First, FIG. 1 shows a first embodiment of the present invention, wherein a plurality of terminals 1A, 2A, and 3A divided into a group A and a plurality of terminals 1 The present invention is applied to a system in which terminals 1B and 2B exist and all of them are controlled by a single control station C.

In the embodiment of FIG. 1, as a result of applying the present invention, individual calls can be made between terminals in the same group for each group, and furthermore, between terminals in the same group, The number of terminals that can transmit (transmit) at the same time is limited to one station, but a conference call can be made without OR synthesis processing of digital voice.

Here, even if it is a conference call, it is rare that a plurality of terminals transmit (transmit) at the same time. Therefore, when all of the plurality of terminals are in the receiving state as in this embodiment, As long as the terminal can also start transmitting arbitrarily, even if the number of terminals that can transmit at the same time is limited to one, there is almost no problem in the conference call.

Hereinafter, when a conference call according to this embodiment, that is, a conference call in which the transmitting terminal is limited to one station, is particularly distinguished, it is referred to as a "limited conference call". If not, simply call it a conference call.

Returning to FIG. 1, in this embodiment, when performing an individual call between the terminals in the radio communication zone Z, a general simultaneous two-way communication using an uplink communication channel fu and a downlink communication channel fd is performed. It operates according to the system, but is configured so that transmission (transmission) and reception (reception) can be switched by the well-known press-talk system (PTT system) during a conference call.

For this reason, each of the terminals 1A to 3A, 1B to 2B
Is provided with a switch for press talk composed of, for example, a push button switch, that is, a press button. At the time of a conference call, the user presses the press button to request a transmission right from the control station C and obtains the transmission right before transmitting. It is configured to start the story.

Therefore, now, terminals belonging to group A,
For example, if the subscriber of the terminal 1A desires a conference call and presses a press button, a transmission request for the conference call is made from the terminal 1A to the control station C via the uplink control channel fcu.

When this is received by the control station C, the control station C selects an available uplink communication channel fu and downlink communication channel fd from the communication channels managed there, and Via fcd,
The terminal 1A is instructed to transmit using this uplink traffic channel fu, and all other terminals in the group A (in this case, the terminals 2A and 3A) are also transmitted via the control channel fcd. , And instructs reception on this downlink communication channel fd.

Thereafter, the control station C receives the signal transmitted from the terminal 1A via the uplink communication channel fu and transmits it via the downlink communication channel fd. As a result, the downlink communication channel f transmitted from the control station C
d signals from all other terminals 2A, 3A in group A
, And therefore, the terminal 1A
Can be used as a transmission terminal.

As described above, it is rare for a plurality of terminals to transmit at the same time even in an original conference call. Therefore, even with this limited conference call, it is possible to sufficiently obtain the same effect as the original conference call. Can be.

The processing at the control station C at this time is as follows:
It is sufficient to simply transmit the signal received on the uplink communication channel fu back through the downlink communication channel fd. Therefore, according to this embodiment, there is no need to perform voice OR synthesis, and it is easy to use a digital system. Conference call.

Further, at this time, in this embodiment, two or more terminals on the receiving side of the conference call
Regardless of the number of units, only one downlink communication channel fd is required to be allocated, so that the number of channels can be reduced and radio waves can be effectively used. At this time,
For the control channels fcu and fcd, each group A,
B may be shared, and in this case, the radio waves can be used more effectively.

Next, the first embodiment of FIG. 1 will be described more specifically with reference to FIGS. First,
FIG. 2 is a diagram showing details of the control station C. Here, the control station C has one system of uplink / downstream control channels fcu / fcd.
And two uplink / downlink communication channels fsu / fsd
, Ftu / ftd. And each terminal 1A,
2A and 3A each have a press button as described above, and when a conference call is desired, the subscriber of each terminal presses the press button and sends a transmission request to the control station C.

The control station C has a control processor 10
And a line control device 20 for connecting the input channel and the output channel, so that an operation required for an individual call between terminals can be obtained. Then, first, the processor 10 executes a predetermined process according to a predetermined program stored therein,
It is configured to perform various controls required by the control station, such as the control of the line controller 20.

Next, as shown in FIG. 3, the processor 10 holds a management table for each of the call groups A to N. As shown in FIG. The channel name assigned to the (talk group), the numbers of all terminals belonging to the group, and bits indicating whether or not the terminal has a transmission right (ON, OFF) are written.

The processor 10 executes a process shown in FIG. 4 when a press button is pressed at any terminal and the control button C receives the press button. Here, the processing in FIG. 4 is processing on the control channel,
The process is a process in a communication channel, and furthermore, an interrupt is initially prohibited by an initial process.

Therefore, when the press button is pressed at any terminal such as the terminal 1A, and this is notified to the control station C via the control channel, the processing of FIG. First, in process S1, FIG.
Is searched, and in step S2, the table of the call group is read.

Next, in step S3, it is checked from the table of this call group whether a call channel has been assigned to the call group. If the result is N (No), that is, if no call channel has been assigned, the process proceeds to step S4. Then, the process proceeds to the process 5 after allocating a vacant communication channel, and when the result is Y (yes), that is, when the channel has been allocated, the process directly proceeds to the process S5.

At this time, although not shown, if there is no available channel, a predetermined program stored in advance is executed to pick up the allocated channel from another group and allocate it, or generate a transmission request. A busy (busy tone) is returned to the terminal 1S so that the terminal 1S waits for an available channel.

In the processing S5, the transmission right bits of all terminals are searched in the table of the communication group, and it is checked whether or not there is a terminal whose transmission right bit is "1" in this communication group. . When the result is Y, the process proceeds to process 6, and when the result is N, the process proceeds to process S7. First, processing S
When the process proceeds to 6, the terminal returns a busy signal to the terminal that has requested the transmission right, that is, the terminal 1A, and is notified that the request for the transmission right is not accepted.

On the other hand, when the process proceeds to step 7, "1" is written into the transmission right bit of the terminal in the table of the call group shown in FIG. 3, that is, the terminal 1A at this time. In step S8, the transmission permission is returned to the terminal 1A via the control channel fcd, and the line controller 20 is controlled to control the input channel fsu and the output channel fs.
d is connected, the control channel is shifted to the communication operation using the communication channel, and then the prohibition of the interrupt for the process is released, and then the process is terminated.

Therefore, as shown in FIG. 2, a conference call is established in which the terminal 1A in the call group A is the transmitting terminal, and all the other terminals A2 in the group A are the receiving terminals. Thereafter, if voice is input to the transmitter of the terminal 1A, it is reproduced as voice from all the receivers of the other terminals 2A to 2A in the group A.

Next, the communication channel is shifted in this way,
Once the one-way conference call has been established, the processor 10
Executes the processing of FIG. This process is periodically executed at predetermined time intervals. First, in process 10, there is a transmission request from a terminal which is a transmitting terminal in a conference call, that is, a terminal 1A at this time via a communication channel. It is checked whether or not, that is, whether or not the press button of the terminal 1A is kept pressed. When the result is Y, that is, when there is a transmission request, the process is terminated as it is.

On the other hand, when the result is N, that is, when there is no transmission request, the process 11S is executed, and "1" written in the transmission right bit of the terminal, that is, the terminal 1A in the table of the communication group is replaced with "1". It is rewritten to "0" and further interrupts for this processing are prohibited, and then the processing is terminated.

Therefore, if the press button is pressed at any terminal thereafter, a conference call is newly established correspondingly to the terminal having pressed the press button as the transmitting terminal. It is possible to make a call in a state that is almost the same as the original conference call.

In this embodiment, during a conference call, a press button is pressed on a terminal other than the terminal that is the transmitting terminal, in this case, any one of the terminals 2A to 3A, and the processing by the processor 10 is performed. Assuming that the terminal has been started, in this case, the result of the process S5 becomes Y and the process S6 is executed, so that a busy is sent to the terminal.

Therefore, in this embodiment, the number of terminals that can be a transmitting terminal during a conference call can always be limited to one station, and as a result, an operation that a conference call can be performed without voice or synthesis processing. It will be surely obtained.

Next, another embodiment of the present invention will be described. FIG. 5 shows a second embodiment of the present invention. In the digital radio communication system of the second embodiment, a base station is provided between a terminal and a control station in order to cope with an expansion of a communication service area, and a hierarchical structure is provided. Things.

Therefore, first, in the embodiment of FIG.
Terminals belonging to the same group are assigned to different base stations 1
To N, and these base stations 1 to N and control station C
Under the control of the control station C, between the terminals belonging to the group under the control of the control station C. It is configured to be able to make a call.

Next, in the second embodiment shown in FIG. 5, terminals belonging to the same group are simultaneously transmitted not only between terminals belonging to the same base station but also to terminals belonging to other base stations. The number of talkable terminals is limited to one, but a conference call can be made without the digital voice OR processing at the control station C.

For this reason, in the embodiment of FIG. 5 as well, each terminal 1A1, 1A2,..., 1AM is provided with a press button as in the first embodiment.
During a conference call, the user presses the press button to request a transmission right from the control station C, and acquires the transmission right before starting transmission.

Now, here, terminals belonging to group A,
For example, assuming that the subscriber of the terminal 1A1 desires a conference call and presses a press button, a transmission request for the conference call is made from the terminal 1A1 to the control station C via the base station 1.

Then, when this is received by the control station C, the control station C selects a vacant uplink communication channel and a vacant communication channel from the communication channels managed there, and the terminal 1A1 An instruction is made via the approach line and the base station 1 to transmit using this uplink communication channel, and the other base stations 2 including the same base station 1,...
.., All the terminals belonging to the same group A in M (in this case, the terminals 2A1, 1A2, and 1AM) are similarly instructed to perform reception on the downlink communication channel via the control channel.

Then, after that, the control station C sets the terminal 1A1
Receives a signal transmitted from the base station 1 via the uplink traffic channel and transmits the signal via the downlink traffic channel to the base station (in this case, base stations 1, 2,... M) is transmitted via the approach line and transmitted through the downlink communication channel.

As a result, the signals of the downlink communication channel transmitted from the control station C are all the other terminals 2A1, 1A2,..., 1A belonging to the group A except for the terminal 1A1.
M will be received at the same time.
A conference call using A1 as a transmitting terminal is established.

Next, the second embodiment of FIG. 5 will be described more specifically with reference to FIGS. First,
FIG. 6 is a diagram showing the details of the control station C. The control processor 10 is connected to a plurality of base stations 1 to M and approach lines 11, 12, 21, 22, 23, m1, and m2. A line control device 20 is provided so that an operation necessary for an individual call between terminals can be obtained.

Then, each terminal 1A1, 2A1, 1A2,
... Each of the 1AMs has a press button as described above, and when a conference call is desired, the subscriber of each terminal presses the press button to send a transmission request to the control station C. Here, the number of approach lines connecting each of the base stations 1 to M and the control station C is arbitrary.

The processor 10 holds a management table for each of the numbers of the communication groups A to N shown in FIG. 7 for line connection control, which is stored in the management table shown in FIG. An additional area for writing the number of the approach line between the station and each base station,
As shown, the numbers of all terminals belonging to each group and the presence / absence of transmission right bits of the terminals are the same.

Here, there is no column for writing the channel name assigned to each group. This is because, in this embodiment, when an approach line is assigned, a channel is assigned by each base station at the same time. Because
Therefore, in this embodiment, the channel assignment is
There is no need to manage with. As in the case of FIG. 3, there is no problem even if the control station C manages the channel assignment to this group, but here, the control station C
The system is not managed by.

FIG. 6 shows that terminal 1A1 belonging to group A of base station 1 requests a conference call, which is accepted by control station C, base station 1 is assigned an approach line 12, and base station 2 is assigned an approach line. Line 21 and base station M
In FIG. 7, an approach line m2 is allocated, and this shows a state in which a conference call in which the terminal 1A1 is a transmitting terminal and the terminals 1A1, 1A2, and 1AM belonging to the same group A are receiving terminals is established.

At this time, the line control device 20 of the control station C
As shown in the figure, the input of the approach line 12 between the base station 1 and the control station C, that is, the approach line input to which the uplink channel of the approach line 12 is connected is set to the downlink channel of the same approach line 12. The processor 10 is controlled to connect in parallel to the downlink channel of the approach line 21 of the base station 2 and the downlink channel of the approach line m2 of the base station M, respectively.

As a result, the signal of the upstream channel of the approach line 12 is transmitted as it is to the downstream channel of the approach line 12, the downstream channel of the approach line 21, and the downstream channel of the approach line m2. , The terminal 1A1 is a transmitting terminal, and the terminals 1A1, 1A2, 1A belonging to the same group A
A conference call using M as a receiving terminal can be established.

FIG. 8 shows the processing by the processor 10 at the time of establishing a conference call. The overall processing flow is the same as that of FIG. 4, except that the processing S3 in the processing is replaced with the processing 30. In other words, the only difference is that the process 4 has been changed to the process 40.
Hanai changed everything.

Therefore, in the second embodiment, the processing S
After reading the management table in step 2, it is first determined in step S30 whether a call group has been established. Here, the state that the communication group has been established means that the communication group has been allocated a communication channel and an approach line, and has already secured a transmission path necessary for the communication.

If the result of the determination in the process 30 is N, the process proceeds to a process 40 after allocating a communication channel and an approach line to the relevant communication group, and proceeds to the process 5 if it is Y. Going to 5,
Other processes are the same as those in FIG.

Therefore, according to the second embodiment,
During a conference call, the number of terminals that can be the transmitting terminal can always be limited to one station. As a result, even in a digital wireless communication system in which the communication service area is expanded by a hierarchical configuration using base stations, there is no voice or synthesis processing. Can make a conference call.

In the above description of the embodiment, the multi-channel system in the digital radio communication system to which the present invention is applied is not particularly limited. The present invention may be applied to a wireless communication system, and can be easily implemented regardless of the application.

Here, a list of multi-channel systems to which the present invention can be applied is given below. An FD in which multi-channeling is realized by a plurality of carriers having different frequencies.
MA system and TDMA using the same carrier in time division
And CDMA.

[0062]

According to the present invention, since there is no need to perform voice or synthesis processing, there is no risk of increasing the amount of hardware or complicating the control contents. A digital wireless communication system can be easily provided at low cost.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a first embodiment of a digital radio communication system according to the present invention.

FIG. 2 is a detailed explanatory diagram of the first embodiment of the present invention.

FIG. 3 is an explanatory diagram showing an example of a management table according to the first embodiment of the present invention.

FIG. 4 is a flowchart for explaining the operation of the first exemplary embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a second embodiment of the digital radio communication system according to the present invention.

FIG. 6 is a detailed explanatory diagram of a second embodiment of the present invention.

FIG. 7 is an explanatory diagram illustrating an example of a management table according to the second embodiment of this invention.

FIG. 8 is a flowchart for explaining the operation of the second exemplary embodiment of the present invention.

FIG. 9 is an explanatory diagram of an individual call operation in an example of a digital radio call system including a plurality of mobile terminals.

FIG. 10 is an explanatory diagram of a conference call operation in an example of a digital wireless communication system including a plurality of mobile terminals.

FIG. 11 is an explanatory diagram of a voice OR synthesis process for an analog signal.

FIG. 12 is an explanatory diagram of audio OR synthesis processing on a digital signal.

[Explanation of symbols]

1A, 2A, 3A, 1A1, 2A1, 1A2, 1AM
Terminal 10 Processor 20 Line connection device

Claims (2)

[Claims] 1. A digital radio communication system comprising at least three terminals and a control station for setting a communication channel between the terminals, wherein the control station includes one of the terminals. Means for supplying audio data received on a channel assigned for transmission to one terminal to one channel assigned for reception to at least two other terminals in common; A digital wireless communication system, wherein one terminal is used as a transmission terminal and at least two other terminals are used as reception terminals so that a conference call with a fixed transmission terminal can be performed between these terminals. 2. A communication system comprising: at least two base stations connected to a control station by respective approach lines; and a plurality of terminals coupled to each of the base stations by radio channels. In a digital radio communication system of a system in which the setting of at least one of the control station and the base station is performed, the control station receives, from another station of the base station, voice data received on an uplink channel of an approach line, and Means for supplying to the downlink channel of the approach line for at least two stations, wherein one terminal among the plurality of terminals is a transmitting terminal, and at least two other terminals are receiving terminals; A digital wireless communication system, characterized in that a conference call with a fixed transmitting terminal can be performed.