JPS6315775B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a regenerative relay device mounted on a satellite in a digital satellite communication system.

Conventionally, the communication method most commonly used in satellite communication systems has been the FDM-FM-FDMA method. However, recently, in order to cope with the increase in the number of earth stations participating in the system and the increase in communication demand,
Furthermore, the introduction of a digital satellite communication system that has high efficiency, large capacity, and can flexibly follow traffic fluctuations is being considered.

As one of these, a digital satellite communication system has been put into practical use, in which a satellite is equipped with a function to convert time slots between TDM signals sent from each earth station.

FIG. 1 is a block diagram showing a configuration example of a satellite-mounted regenerative repeater used in the above-mentioned digital satellite communication system. In the figure, 1 is a receiving antenna of a communication satellite, 2 is a receiver, 3 is a demodulator, 4 is a switch matrix that switches connections between a plurality of input signals and a plurality of output signals at high speed,
5 is a modulator, 6 is a carrier wave generation circuit, and 7 is a transmitting antenna of a communication satellite. Note that a multi-feed multi-beam antenna, a beam scan antenna, or the like is applied to the receiving antenna and the transmitting antenna.

In the case of the conventional example shown in FIG. 1, a signal received by a receiving antenna 1 is amplified and frequency converted in a receiver 2, demodulated into a digital signal in a demodulator 3, and then guided to a switch matrix 4. . In the switch matrix 4, time slot conversion is performed between a plurality of digital signals, and the output signal thereof is guided to a modulator 5, where it is modulated by a carrier wave sent from a carrier wave generation circuit 6.

What consumes the most power in the signal processing process described above is the amplification of the carrier wave in the carrier wave generation circuit 6. Generally, satellite communication systems are
Since there are severe restrictions on power supply, how to use power supply effectively has become an important point in the economic design of satellites. Therefore, highly efficient use of the carrier wave generated by the carrier wave generation circuit 6 is extremely important for optimal design of the satellite system.

The present invention has been made in view of the above-mentioned prior art, and an object of the present invention is to provide a regenerative repeater installed on a satellite that can save power consumption by efficiently using carrier waves generated within the satellite. purpose.

Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 2 shows a first embodiment of a satellite-mounted regenerative repeater to which the present invention is applied. In this embodiment, a carrier distribution circuit 8 is provided between the carrier generation circuit 6 and the modulator 5.
This carrier wave distribution circuit 8 is provided with the function of the switch matrix 4 shown in FIG. 1 equivalently. FIG. 3 is a diagram illustrating the procedure for distributing received signals and carrier waves, with time t plotted on the horizontal axis, and the embodiment of FIG. 2 will be explained using this diagram. The signal received by the receiving antenna 1, receiver 2, and demodulator 3 has a TDMA frame length T divided into sections τ ₁ , τ ₂ , and τ ₃ as shown in _FIG .
contains information for beam A of the transmitting antenna 7, section τ ₂ contains information for beam B, and section τ ₃ contains information for beam C. In order to connect these pieces of information to the beams of the transmitting antenna 7 for their respective purposes, the carrier wave generation circuit 6 is used in this embodiment.
The output is supplied to each modulator in a time-division manner by a carrier wave distribution circuit 8. That is,
As shown in FIG. 3b, the continuous carrier wave which is the output of the carrier wave generation circuit 6 is transmitted to the modulator 5A in the interval τ ₁ as shown in the figure c, and to the modulator 5B in the interval τ 1 as shown in the figure 3d. The signal is supplied to _{the modulator 5C in the interval τ 2 as} shown in FIG. Therefore, it can be considered that the carrier wave distribution circuit 8 shares a part of the function of the switch matrix 4 shown in FIG.

FIG. 4 shows the present invention having a plurality of receiving beams.
Furthermore, an embodiment in which the present invention is applied to a satellite-mounted regenerative repeater having a signal processing function will be described. In the figure,
9 is a signal processing circuit, and other symbols are the same as in FIGS. 1 and 2. 5 and 6 show the received signals of this embodiment. In each figure, a is the received signal by beam A of the receiving antenna 1, b is the received signal by beam B, and c is the received signal by beam C. shows the received signal by

First, a case will be described in which an intermittent signal as shown in FIG. 5 is received. When the speed of the received signal and the speed of the transmitted signal are the same, the signal processing circuit 9
The carrier distribution circuit 8 only needs to have a switching function similar to the switch matrix shown in FIG. to be distributed. If the received signal speed and the transmitted signal speed are different, the signal processing circuit 9 will have a speed exchange function in addition to the switching function. In this case, the carrier wave distribution circuit 8 receives route information, switching timing information, and time slot length _Tt information from the signal processing circuit 9, and distributes the carrier wave to each modulator 5.

Next, the case of receiving continuous signals as shown in FIG. 6 will be explained. In this case, the speed of the received signal is slower than the speed of the transmitted signal,
It is essential that the signal processing circuit 9 has a speed conversion function. The signal processing circuit 9 uses a predetermined procedure to generate a signal equivalent to the signal shown in FIG. good.

Next, FIG. 7 shows a configuration example of a satellite-mounted regenerative repeater that is a modification of the one shown in FIG. 4. The signal processing circuit 9 of this configuration example has a time division multiplexing function in addition to a switching function and a speed conversion function, and after receiving the signals shown in FIGS. 5 and 6, processes the received signals. In addition, a time division multiplexed signal 10 is created.
In this case as well, the carrier wave distribution circuit 8 according to the present invention can be applied so as to operate in the same manner as the embodiment shown in FIG.

Additionally, the present invention can be implemented using multiple carrier waves.
An example of the configuration when applied to a TDMA system will be described. FIG. 8 shows an example of the configuration of the modulator 5, the carrier distribution circuit 8, and the carrier generation circuit 6 that generates frequencies ₁ , ₂ , and ₃ . Incidentally, for the configuration before and after the modulator 5, either of the embodiments shown in FIG. 4 and FIG. 7 can be applied. FIG. 9 shows the received signal and carrier wave distribution procedure with time t plotted on the horizontal axis. In Figure 9, 1,
2 and 3 are received signals from receive beams A, B, and C, indicating the destination transmit beam and transmission frequency, and 4, 5, and 6 are modulation signals supplied with each carrier wave of ₁ , ₂ , and ₃ . 7, 8, and 9 indicate frequencies to which each modulator 5A, B, and C is supplied. In this embodiment, the carrier wave distribution circuit 8 is considered to be a switch matrix with multiple inputs and multiple outputs, and its operation can be explained in principle as shown in FIGS. 4
It is sufficient to operate in the same manner as the embodiment shown in FIGS.

As described above, according to the present invention, a carrier distribution circuit is provided between the modulator and the carrier generation circuit,
By appropriately operating this, it is possible to effectively utilize the carrier wave generated by consuming the largest amount of power on the communication satellite, which has the advantage of achieving highly efficient use of satellite power. In particular, if the present invention is applied to a communication system such as a maritime satellite communication system, which has a sufficient amount of allocated frequency bandwidth, but wants to use satellite power as effectively as possible,
It can make a big impact. Further, according to the embodiment shown in FIG. 8, it is possible to easily configure a TDMA system using a plurality of carrier waves, which requires carrier waves to be appropriately switched for each time slot on a communication satellite.

In addition, in explaining the above-mentioned embodiments and application examples, for convenience of explanation, the number of receiving and transmitting antennas (number of beams) was set at a maximum of 3, and the number of divisions of the frame length T was also set at a maximum of 3. The number does not limit the implementation of the present invention.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of the configuration of a conventional regenerative repeater for use on a satellite, Fig. 2 is a block diagram showing an embodiment of the present invention, and Fig. 3 is for explaining the operation of the embodiment of Fig. 2. 4 is a block diagram showing another embodiment of the present invention, and FIGS. 5 and 6 are time charts.
The figure is a time chart for explaining the operation of the embodiment of FIG. 4, FIGS. 7 and 8 are block diagrams showing still other embodiments of the present invention, and FIG. 9 is a diagram of the embodiment of FIG. 8. This is a time chart to explain the operation. DESCRIPTION OF SYMBOLS 1... Receiving antenna, 2... Receiver, 3... Demodulator, 4... Switch matrix, 5... Modulator, 6... Carrier wave generation circuit, 7... Transmitting antenna, 8... Carrier wave distribution circuit , 9...signal processing circuit.

Claims (1)

[Claims] 1 a receiving antenna for receiving a receiving beam, a receiver, a demodulator, a plurality of modulators, a transmitting antenna for transmitting a plurality of transmitting beams,
a carrier wave generation circuit that supplies at least one carrier wave to the modulator, and a carrier wave distribution circuit provided between the modulator and the carrier wave generation circuit; means for time-divisionally distributing and supplying the at least one carrier wave to the modulator using route information and switching timing information for specifying the plurality of transmission beams determined from the received signal demodulated by the A regenerative relay device for use on a satellite.