JPS60220630A - Remote station of communication equipment - Google Patents

Abstract

PURPOSE:To constitute economically an SCPC modulating and demodulating part in a remote station by switching a common SCPC modulator and demodulator for common signal line and audio line to connect this SCPC modulator and demodulator to an audio line device or a common signal line device by a switching means. CONSTITUTION:A satellite communication system of the centralized control SCPC- DAMA system consists of a communication satellite 1, a central station 2, and plural remote stations 3a-3n. In case of call collection between remote stations 3a and 3b, an SCPC carrier for common signal line is set to common SCPC modulator and demodulator 14c and 15c for common signal line and audio line from a frequency synthesizer 16c by the control of a controller 20. When the station 3a detects an originating call through an earth interface device 17 by the controller 20, the assignment request of a carrier for audio line is sent to the central station 2 through the satellite 1. When the central station 2 sends an assigning signal, stations 3a and 3b receive it, and a designated SCPC carrier frequency for transmission and reception sounds is set from the synthesizer 16c to the modulator 14c and the demodulator 15c, and the modulator and the demodulator are switched to be connected to the device 17 by a changeover switch 32.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a remote station in a centrally controlled fully variable multiple access type (hereinafter referred to as SCPC-DAMA system) communication device, and in particular, to a remote station in a 5 cpc This relates to the configuration of a modem.

[Prior art]

One of the most important applications to which this type of technology has been applied is a satellite communication system. The following will explain the case of satellite communication as an example.

The satellite communication system operated by the centrally controlled SCPC-DAMA system consists of a communication satellite 1 as shown in Figure 1.
, a central station 2 that allocates satellite lines and manages the network, and a plurality of remote stations 3a, 3b, 3
Consists of n. FIG. 2 shows an example of the arrangement of radio carriers used by the central station 2 and the remote stations 33 to 3n within the repeater of the communication satellite I. In the figure, 4.5 is a common signal line for transmitting and receiving signals necessary for connection control of call 1 between each remote station 3 and the central station 2. The signal from 3 to the central station 2 uses the 5cpc carrier 4 for the uplink common signal line, and the signal from the central station 2 to the remote station 3 uses the 5cpc carrier 5 for the downlink common signal line. For signal line 5
Let the frequencies of the cpc carrier 4°5 be rO and fl, respectively. 6a to 6n are 5 CPC carriers for voice lines, which are assigned in pairs between calling and receiving stations by the central office 2, and constitute a communication path. Let the frequency of each of these be f2. f3. .....

Figure 3 shows the 5cpc carrier 5 for the downlink common signal line.
An example is shown in which the central station 2 uses a time division (TDM) method, and here, to simplify the explanation, there are 3 remote stations.
A case is shown in which the stations are composed of stations 3a to 3C. In the figure, 7 indicates the TDM burst position sent from the central station 2, which includes information 8, 9, and 10 for each remote station 3a to 3C.

This TDM burst 7 is repeated on the time axis at a period as shown in the figure.

Figure 4 shows the 5cpc carrier 4 for the uplink common signal line.
An example is shown in which each remote station 33 to 3c uses a time division multiple access (TDMA) method, and corresponding to FIG.
12 and 13 indicate the TDMA burst positions transmitted by the remote stations 3a, 3b, and 3c, respectively. Each TDMA burst 1
1. 12. 13 are repeated in this order on the time axis.

FIG. 5 shows the relevant main equipment at the remote station 3. In this example, in order to simplify the explanation, one 5 cpc modem for voice lines and one 5 cpc modem for common signal lines are shown.

In the figure, 14a and 15a are 5cpc modems exclusively for voice lines, 14b and 15b are 5cpc modems exclusively for common signal lines, and 16a and 16b are 5cpc modems 14a and 1, respectively.
This is a frequency synthesizer for setting transmitting and receiving carrier frequencies to 5a, 14b, and 15b. The common signal line 5cpc modulator 14b has a carrier frequency fO
Revenge! 115b is the synthesizer 16 fixed to fl.
It is set by b. Also each 5cpc modem 1
4a, 14b, 15a, and 15b are connected to wireless equipment 21 including an antenna. In addition, 17 is a ground interface device that performs communication path separation connection, exchange connection, and detection/sending of exchange signals between the terrestrial trunk line 22 and the communication path 5CPC modem 14a, 15a, and 18.19 is a common signal Line data modulator/demodulator, 20 monitors/demodulates the above equipment.
This is a control device that performs control. Note that the central station 2 also has a similar configuration to such a remote station.

Next, a call connection operation between remote stations in the conventional device configuration as described above will be explained according to an example of a signal sequence shown in FIG.

First, when a call 23 is received from the ground relay line 22 to the remote station 3a, the control bag w, 20 of the remote station 3a sends a call signal such as an activation signal or a dial pulse to the ground interface device 1.
7 and stores the dialed digits. When the number of digits required for terminating station identification is detected, it is sent as an allocation request signal 2.
Set within 4, data modulator 18.5CPC modulator 1
5cp for uplink common signal line at frequency fO via 4b
c TDMA burst 1 from remote station 3a on carrier 4
Send as 1. Note that the TDMA burst synchronization control method, burst format, signal format, etc. are not directly related to the present invention and will therefore be omitted.

The central office 2 that received the allocation request signal 24 transfers the 5cpc carrier for the vacant voice line (5a in this case).

6b) frequency f2. Line assignment signal 2 including f3
5a and 25b, respectively, to the originating remote station 3a.

To the receiving remote station 3b, the remote station 3a of TDM burst 7 on the downlink common signal line 5cpc carrier 5 at frequency f1.
, 3b is set at position 8.9 and sent. The line assignment signal 25a to the remote station 3a includes the signal 5 for an empty voice line.
The frequencies of CPC carriers 6a, 6b transmit at f2. When reception is set to f3, the same signal 25b to remote station 3b includes transmission f3. Reception f2 is set as the transmission and reception frequency.

The above line assignment signals 25a and 25b are demodulated by 5cpC I
II 5 b, the control device 2o of the remote station 3a, 3b received via the data demodulator 19 receives the frequency synthesizer 1
6a, the line assignment signals 25a and 25b specify the
The received transmission and reception frequency is set to the voice line dedicated 5cpc modulators 14a and 15a.

Next, using the communication path set between the remote stations 3a and 3b, the continuity test sound 26a is sent from the remote station 3a to 3b from the ground interface device 17 via the 5CPC modulator 14a, and the continuity test sound 26a is sent from the ground interface device 17 to the remote station 3b. , this continuity test sound 26a is 5c
PC demodulator 15a.

When detected by the control device 20 via the ground interface device 17, the ground interface 17,
A continuity test sound 26b is sent out via the 5CPC modulator 14a. Similar to that detected by remote station 3b, continuity test sound 2
6b, the remote station 3a sends a channel conduction signal 27 to the central station 2 using the uplink common signal line, and
The necessary accumulated dial signal 28 is sent to the remote station 3b using the set communication path.

The central station 2, which receives the channel guidance signal 27 sent from the remote station 3a, knows that the assigned channel is normal.

Further, the remote station 3b sends the dial signal 28 sent from the remote station 3a to the ground trunk line 22 via the ground interface device 17. Thereafter, a response signal 29 from the trunk line 22 establishes a communication state between the remote stations 3a and 3b.

Further, each remote station 3a, 3b sends a call termination signal 30a.

30b via the ground interface device 17, the remote stations 3a and 3b send this to the central station 2 as recovery signals 31a+31b, respectively, using the uplink common signal line, and also send the signal to the central station 2 using the 5CPC modem 14 dedicated to the voice line.
a, the frequency f2. which was set to 15a. Release f3.

The central office 2 that has received the restoration signal 318.31b returns the voice line 5cpc carriers 6a and 6b to their original free state.

In the above operation description, the signaling system and connection system on the terrestrial trunk line 22, as well as the hardware configuration of the corresponding terrestrial interface device, are not directly related to the present invention and will therefore be omitted. The same applies to the control device 20.

In a remote station in such a conventional system, as shown in FIG.
Even if there is only one set of 15a, that is, there is only one communication channel, the 5CPC modem 14b, 15 dedicated to the common signal line
b), which is disadvantageous in that it is uneconomical in terms of the structure of the device.

[Summary of the invention]

This invention was made in order to eliminate the above-mentioned drawbacks of the conventional ones, and in a remote station of an SCPC-DAMA communication device, a 5 cpc modem for common signal line and a 5 cpc modem for voice line are installed. By sharing the shared 5cpc modem with the voice line device or the common signal line device using a changeover switch, the configuration of the 5cpc modem converter section can be simplified. The purpose is to provide a remote station for a DAMA type communication device.

[Embodiments of the invention]

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 7 shows related main equipment of a remote station according to an embodiment of the present invention, and in the figure, the same reference numerals as in FIG. 5 indicate the same or corresponding parts. 14C and 15C are common 5c provided for both the common signal line and voice line, respectively.
The PC modulator and demodulator 16c is a frequency synthesizer 32a that sets the transmission and reception carrier frequency of the common 5CPC modulators 14c and 15c according to instructions from the control device 20.
.

32b is the common sc p c' by the control device 20.
Modem/demodulator 14c, 15c and ground interface device 1
7 or a data modulator/demodulator 18 or 19, and this switch 32 and the control device 20 constitute a switching control means.

Note that the central office 2 is configured as shown in FIG. 5 in the same manner as in the prior art.

Next, a call connection operation between the remote stations 3a and 3b having such a device configuration will be explained according to the sequence shown in FIG.

When the trunk line 22 is idle, each remote station 3a.

The changeover switch 32 of 3b is connected to the data modulator/demodulator 18, 19 side, as shown in FIG.

The shared 5CPC modulators 14c and 15c also transmit and receive 5CPC carriers 4 and 5C for the common signal line whose transmitting and receiving carrier frequencies are shown in FIG. 2 by the frequency synthesizer 16c.
It is set to 5. That is, the shared 5 cpc modulator 14c
The frequency fO is set by the control device 20 to 1, and the frequency f1 is set to the common 5cpc deactivator 15'C. Naturally, the frequency fl is set to the 5cpc modulator for the common signal line of the central station 2, and the frequency "0" is set to the 5cpc demodulator.

Now, when a call 23 is received from the trunk line 22 of the remote station 3a, the control device 20 detects this via the ground interface device 17, and thereby sends an allocation request signal from the remote station 3a in the same manner as in the conventional operation. 24 is sent to the central office 2. Then, line assignment signals 25a and 25b are sent from the central station 2, and the remote stations 3a and 3b receive these signals, respectively.

The remote stations 3a and 3b set the 5cpc carrier frequency for transmitting and receiving audio specified by the received line assignment signals 25a' and 25b, respectively, to the shared 5cpc modem 14C 115c via the frequency synthesizer 16c. That is, the remote station 3a has a transmission frequency f2. The receiving frequency 13 is transmitted to the remote station 3b, and the transmitting frequency f3. Reception frequency [2 is set. At the same time, the changeover switch 32 is switched, and the connection is made to the ground 'I Tsuta-Ace device 17 side (
state shown by the broken line in Fig. 7).

In this way, each remote station 3
After the transmitting/receiving carrier frequencies of a and 3b are set, the continuity test of the communication path is performed using continuity test sounds 26a and 26b as in the conventional case.
It is done by Then, the frequency of the shared 5CPC modem 14C of the remote station 3a is returned to rO, and the selector switch 32a
After connecting to the data modulator 18 side, the channel conduction signal 2
7 to the central office 2. And after that, shared 5cpc
The frequency of the modem 14c is reset to f2, and the changeover switch 32a is connected to the ground interface device 17 side. The dial signal 28 and response signal 29 are performed in the same manner as in the conventional case.

The call termination signals 30a and 30b are sent to the remote station 3a.

3b, the remote stations 3a and 3b return the frequencies set in the common 5cpc modulators 14c and 15c to fo and fl, respectively, and change the changeover switch 32 to the data modulator 18 and 19 side. connection, and a recovery signal 31a,
31b to the central office 2.

As described above, each remote station 3a, 3b shares 5cp
A changeover switch 32 is provided between the c modems 14c and 15c, the ground interface device 17, and the common signal line data modem 18, 19, and the ground interface device 17 or the data modem 18, 19 is installed as necessary in the process of call connection. The shared 5cpc modulators 14c and 15c are switched and connected to the frequency synthesizer 16C.
The transmitting and receiving carrier frequencies of the shared 5cpc modulators 14C and 15C are set according to the line used at that time via the conventional common signal line dedicated 5cpc.
5CPC modem 14b without changing the call connection sequence in any way compared to the case where PC modem 14b and 15b are provided.
, 15b can be reduced, and the hardware configuration of each remote station can be made simple and inexpensive.

Although the above embodiment has been explained using satellite communication as an example, the present invention can also be applied to terrestrial mobile radio communication, and although telephone communication has been explained as an example, it is of course applicable to data communication as well. .

Further, the common signal line modem is not limited to the transmission speed or the mode/demodulation method, and the communication path may be a plurality of communication paths. Further, the basic principle of the present invention can also be applied to a TDMA system in which the communication path is configured.

〔Effect of the invention〕

As described above, according to the present invention, the 5C for common signal line
Since the PC modem and the 5CPC modem for voice lines are shared, and the shared 5CPC modem and the voice line device or the common signal line device are switched and connected by a changeover switch, 5CPC modem and demodulation at a remote station is possible. This has the effect that the organ part can be constructed easily and economically, and the device can be made inexpensive.

[Brief explanation of the drawing]

Figure 1 shows an example of a satellite communication system operated by the centrally controlled SCPC-DAMA system, Figure 2 shows an example of the arrangement of 5cpc carriers in a communication satellite repeater, and Figure 3 shows an example of the arrangement of a 5cpc carrier in a communication satellite repeater. Figure 4 shows an example of access to the common signal line using the TDM (time division multiple access) method. Figure 4 shows an example of access to the uplink common signal line using the TDMA (time division multiple access) method. 5 is a diagram showing the main part configuration of a conventional remote station, FIG. 6 is a diagram showing an example of call connection control between remote stations in the SCPC-DAMA system, and FIG. 7 is a diagram according to an embodiment of the present invention. FIG. 2 is a configuration diagram of main parts of a remote station. 1...Communication satellite, 2...Central station, 3...Remote station,
14C...shared 5cpc modulator, 15C...shared 5
cpc demodulator, 17... ground interface device (
voice line equipment), 18.1? ...Data modem (
common signal line device), 20...control device, 32a. 32b... Selector switch. Note that the same reference numerals in the figures indicate the same or equivalent parts. Agent Masuo Oiwa Figure 2

Claims (1)

[Claims] (1) Consisting of one central station and many remote stations, one
A single voice line is configured using a carrier wave, and multiple voice lines are set up by frequency division, and the central station grasps all usage status of the voice line group, and each remote station transmits information to the central station each time a call occurs. A remote station of a fully variable multiple-access single-carrier type communication device under centralized control issues a voice line allocation request via the common signal line to the central station and allocates the vacant voice line at the central station. It is characterized by comprising a common 5CPC modem provided for both voice lines, and a switching control means for switching and connecting the common 5CPC modem and the voice line device or the common signal line device. A remote station of a fully variable multiple-access single-carrier communications device. .