JPH01188038A - Satellite communication system - Google Patents

Abstract

PURPOSE:To prevent the adverse effect onto a repeater in an artifitial satellite due to excess level input by using a monitor control means so as to grasp the transmission state of each earth station in the network and operating the network by overall transmission power within a prescribed input level of the allocated repeater of the artifitial satellite. CONSTITUTION:A monitor controller 7 of each slave station monitors and graps the transmission state of its own station at all times and sends the transmission state to a master station controlling the network via a transmission frequency converter 2, a power amplifier 3 and an antenna system through the artifitial satellite. The monitor controller 7 grasps the transmission state of each earth station in the network and the network is operated by the overall transmission power within the prescribed input level range of the repeater in the artifitial satellite assigned to the network. Thus, the adverse effect onto the repeater in the artifitial satellite due to excess level input or the like is surely avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a satellite communication system in which a plurality of earth stations constituting a network communicate with each other via one artificial satellite.

[Prior Art] FIG. 2 is a block diagram showing the configuration of an earth station in a conventional satellite communication system, compared to FIG.

1 is a terminal device that modulates and demodulates audio and images, 2 is a terminal device 1
3 is a power amplifier that amplifies the signal to be transmitted to the required transmission power; 4 is a power amplifier that radiates the transmission signal to the artificial satellite; An antenna device receives a signal from an artificial satellite, 5 is a low-noise amplification device that amplifies the received signal with low noise, and 6 is a reception frequency conversion device that converts the received signal into an IF signal. 1. Normally, a network is constructed of a plurality of earth stations having such a configuration, and communication between the earth stations within this network is performed via a repeater in an artificial satellite (not shown).

Next, the operation will be explained. An information signal obtained by a telephone, a video camera, etc. is modulated by a terminal device 1 and frequency-converted by a transmission frequency converter 2.
Furthermore, after being amplified to the required transmission power by the power amplification device 3, the signal is radiated from the antenna device 4 to an artificial satellite (not shown). The signal relayed by the repeater in the artificial satellite is received by the antenna device 4 in another earth station, and is received by the low noise amplification device 5. It is demodulated by the reception frequency conversion device 6 and the terminal device 1.

[SLJ' to be solved by the invention] The conventional satellite communication system is configured as described above, and can perform transmission for the number of installed channels with the transmission power per channel specified in advance in the network. For example, when transmitting on two channels in a network with multiple stations, if an image signal or the like exceeds the assigned input level of the repeater in the satellite, if multiple stations transmit at the same time, the level will be excessive and the satellite will be interrupted. There were problems such as the risk of having an adverse effect on the internal repeaters.

This invention was made in order to solve the above-mentioned problems, and it is possible to operate with a transmitting power lower than the input level of the repeater in the satellite allocated to the entire network. The purpose is to obtain a satellite communication system that prevents negative effects on

Is it true? A satellite communication system according to the present invention monitors the transmission status of each of a plurality of earth stations and determines the total transmission power of each earth station in the network by specifying the total transmission power of each earth station in a repeater in an artificial satellite. It is equipped with a monitoring control means that can maintain and control the input level below.

[Function] In the satellite communication system of the present invention, the monitoring and control means grasps the transmission status of each earth station in the network, and calculates the total sum within a predetermined input level range of the repeaters in the artificial satellite assigned to the network. The above network is operated using the transmission power.

[Embodiment of the Invention] An embodiment of the invention will be described below with reference to the drawings. 1st
The figure is a block diagram showing the configuration of an earth station in a satellite communication system according to an embodiment of the present invention. In the figure, the same reference numerals as those already described indicate the same parts, so the explanation thereof will be omitted.

In Figure 1, 7 is a monitoring and control device (supervisory control means) provided in each of the multiple earth stations (including a master station and multiple slave stations) that make up the network, and monitors and understands the transmission status of its own station. However, it controls the transmission status of its own station so that the total transmission power of each earth station in the network is maintained below the specified input level of a repeater in an artificial satellite (not shown).

Next, the operation of a satellite communication system having a network including a plurality of earth stations configured as shown in FIG. 1 will be explained. In addition, here, one of the multiple earth stations
A case will be described in which the station is a master station and the master station centrally monitors and controls the transmission and reception of other slave stations.

Normal transmission and reception at each earth station is performed in exactly the same way as the conventional one shown in FIG. In the system of this embodiment, each slave station always monitors the transmission status of its own station using the control device 7.
It monitors and understands the transmission status, and transmits the transmission status via the transmission frequency converter 2, 1t power amplifier 3, and antenna device 4 to the master station that controls the network via the artificial satellite.

In this way, the master station grasps the transmission status obtained from each slave station within the network. After grasping the transmission status, the master station instructs the slave stations that have requested transmission whether or not to transmit so that the network can be operated with the total transmission power within the specified input level range of the satellite repeater assigned to the network. The information is transmitted via satellite to the monitoring and control device 7 of each slave station.
tell to. The monitoring and control device 7 of each slave station controls the transmission status based on the information from the master station as to whether transmission is possible or not.

As described above, according to the system of the present embodiment, the monitoring and control device 7 grasps the transmission status of each earth station in the network, and calculates the total input level within the predetermined input level range of the satellite repeaters assigned to the network. Since the network can be operated using the total transmission power, it is possible to reliably prevent harmful effects such as excessive level input on repeaters in the satellite.

In the above embodiment, a case has been described in which each slave station grasps the transmission status of the entire network by transmitting the transmission status collected by the supervisory control device 7 to the master station. However, within the band occupied by the network, the communication status of the entire network may be grasped by the reception system of the master station, and transmission control may be performed for each slave station. In this case, the monitoring from each slave station Since there is no need to rely on signals, a more reliable line control system can be obtained.

Furthermore, the monitoring and control device 7 of each slave station may be provided with a function of grasping the communication status of the entire network using the receiving system of the own station and controlling transmission within the own station. Therefore, a more reliable line control system can be obtained.

[Effects of the Invention] As described above, according to the present invention, the monitoring and control means grasps the transmission status of each earth station in the network, and the transmission status of the satellite repeater assigned to the network is within the predetermined input level range. Since the network is configured to operate with a total transmission power of

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an earth station in a satellite communication system according to an embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of an earth station in a conventional satellite communication system. In the figure, 7--monitoring control device (monitoring control means). In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] In a satellite communication system in which multiple earth stations that make up a network communicate with each other via a repeater in an artificial satellite, the transmission status of each of the multiple earth stations is monitored and the transmission status of each earth station within the network is monitored. A satellite communication system characterized by comprising a monitoring control means capable of maintaining and controlling the total transmission power below a specified input level of the repeater.