JP3047577B2 - Satellite communication equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is used for automatic frequency control. In particular, the present invention relates to a technique for preventing erroneous carrier drop-in when narrowband signals are arranged adjacently.

[0002]

2. Description of the Related Art The configuration of a conventional example will be described with reference to FIG. FIG. 4 is a diagram illustrating a conventional example.

FIG. 4A is a configuration diagram of a conventional apparatus.
Communication data is input from a data input terminal 1 to an error correction encoding circuit 2. A carrier ID for identifying a carrier for each channel is inserted into the output of the error correction encoding circuit 2 by a carrier ID insertion circuit 11. This signal is input to the modulator 4 and the output is transmitted from the data transmission terminal 5. The signal form is as shown in FIG.

The communication data arrives at the data receiving terminal 6 via the satellite 10. The communication data input to the demodulator 7 is demodulated and is demodulated by the carrier ID identification circuit 12 therein.
It is determined whether the received signal is due to the intended carrier. If the received carrier is the intended carrier, the carrier ID identification circuit 12 instructs the AFC 14 to stop the carrier sweep. If different, the AFC 14 continues the carrier sweep until the object is further achieved.

In satellite communication, the center frequency of a carrier is searched for by a frequency sweeping means called AFC in order to compensate for the center frequency deviation of the carrier caused by frequency fluctuations of satellites and systems. In this case, since the search is performed up to both the left and right sides of the carrier to be searched, it is not known which carrier is really the carrier to be searched, so that a different carrier may be caught. Therefore, there is a method in which the data is formed into a frame, the carrier ID bits are multiplexed in the frame bits on the transmission side, and the operation of the AFC 14 is continued on the receiving side by referring to the carrier ID bits until the carrier of the carrier ID to be actually searched. Has been taken.

[0006]

In the conventional carrier wave sweeping method, extra information bits such as a synchronization word channel ID are added to transmission data to prevent erroneous sweeping, which leads to an increase in transmission speed and an increase in hardware scale. There was a problem.

The present invention has been made in view of such a background, and provides a satellite communication apparatus capable of preventing erroneous sweep of a carrier wave without increasing the transmission rate of communication data even if the sweep range of AFC is widened. Aim.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a data input terminal for inputting communication data, an error correction coding circuit for error correction coding data input from the data input terminal, and an error correction coding circuit for the error correction coding circuit. A modulator for modulating the communication data output from the transmitter, a data transmission terminal for transmitting the communication data modulated by the modulator, and data for receiving the communication data transmitted from the data transmission terminal and arriving via a satellite. A receiving terminal, a demodulator for demodulating communication data from the data receiving terminal, an error correction decoding circuit for error correcting and decoding the output of the demodulator, and a carrier wave pull-in for receiving a carrier wave for receiving the communication data And a carrier unit, wherein the carrier pull-in unit includes an adjacent carrier wave of the communication data signal sequence output from the error correction coding circuit. Means for rearranging differently ordering the communication data signal sequence, characterized in that it comprises a means for restoring a signal sequence of the communication data reordering the order in which they are outputted from the demodulator.

Preferably, the means for rearranging includes means for interchanging the next two burst-like data signals with each other.

Further, the error correction decoding circuit includes a synchronization detection output terminal, and the carrier pull-in section includes means for fixing a reception frequency and a phase when a synchronization state is transmitted to the synchronization detection output terminal. The means for rearranging comprises:
It is preferable to include means for stopping the rearrangement operation when a synchronization state is sent to the synchronization detection output terminal.

[0011]

The signal sequence of the communication data is converted by the data rearranging circuit.
Rearrangement is performed according to the regularity from the rearrangement control circuit. The regularity is that different permutations are performed at least between channels having adjacent carriers. Although the communication data contents are different for each channel, the order of the signal sequence is regulated, and the regulation is broken by the data rearranging circuit.

The communication data is sent back to the ground via a satellite. On the receiving side, the data rearranging circuit instructs the data rearranging circuit to perform a restoration procedure using the regularity of rearranged target channels in reverse. . When the communication data arrives at the data receiving terminal, the AFC searches for and sweeps the carrier of the target channel. At this time, if the swept carrier wave is that of the target channel, the communication data is correctly restored by the data rearrangement circuit and input to the error correction decoding circuit. The error correction decoding circuit can synchronize the error correction decoding only when the communication data is correctly restored, but does not synchronize the error correction decoding, so that it is possible to identify whether the swept carrier is the intended one. You. When the carrier is identified as the target carrier, the error correction decoding circuit issues an instruction to stop sweeping to the AFC.
The FC stops the sweep with the frequency and phase fixed. At the same time, the rearrangement control circuit also receives this instruction and stops rearranging the signal sequence.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention.

The present invention provides a data input terminal 1 for inputting communication data, an error correction coding circuit 2 for error correction coding data input from the data input terminal 1, and an output signal from the error correction coding circuit 2. A modulator 4 for modulating the communication data obtained, a data transmission terminal 5 for transmitting the communication data modulated by the modulator 4, and the communication data transmitted from the data transmission terminal 5 and arriving via the satellite 10. A data receiving terminal 6 for receiving data; a demodulator 7 for demodulating communication data from the data receiving terminal 6; an error correction decoding circuit 8 for error correcting and decoding the output of the demodulator 7; In a satellite communication apparatus provided with a carrier drop-in unit 3 for pulling in a carrier wave, the carrier drop-in unit 3 is adjacent to a signal sequence of the communication data output from the error correction coding circuit 2. A data rearranging circuit 15 as means for rearranging the order of the communication data signal sequence of the carrier wave to be changed, and a data rearranging circuit as means for restoring the sequence of communication data output from the demodulator 7 and rearranging the sequence. 15 ^′ .

The rearranging circuits 15 and 15 ^′
This is a configuration including means for replacing the following two burst-like data signals with each other.

Further, the error correction decoding circuit 8 is provided with a synchronization detection output terminal 17, and the carrier pull-in section 3 is provided with means for fixing the reception frequency and phase when the synchronization state is transmitted to the synchronization detection output terminal 17. Provided in the rearrangement control circuit 16, the rearrangement circuits 15 and 15 ^′ include means for stopping the rearrangement operation according to the instruction of the rearrangement control circuit 16 when the synchronization state is transmitted to the synchronization detection output terminal 17.

Next, the operation of the apparatus according to the embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a diagram showing data rearrangement control. FIG. 3 is a diagram showing a communication data signal sequence in the AFC sweep range.

Communication data is input from a data input terminal 1 and input to an error correction coding circuit 2. The error correction coding in the apparatus according to the embodiment of the present invention is based on the Viterbi decoding method.
The error correction coded communication data is input to the data rearranging circuit 15. For example, when the transmission channel is 1CH and the rearrangement control signal from the rearrangement control circuit 16 is at a high level, the data rearrangement circuit 15 selects the B side and outputs the data to the Y side. As shown in FIG. 7, P and Q are reversed as compared to the case where P and Q do not pass through the data rearrangement circuit 15. Rearrangement control circuit 1
Numeral 6 controls rearrangement so that adjacent channels are arranged differently as shown in FIG. The signal input to the modulator 4 is modulated and transmitted from the data transmission terminal 5.

On the other hand, the data inputted from the data receiving terminal 6 is demodulated by the demodulator 7 and the data rearrangement circuit 15
^'Is entered. The data rearrangement circuit 15 ^' receives a rearrangement control signal for restoring communication data corresponding to the selected reception channel, for example, 1CH, from the rearrangement control circuit 16, and waits. By this rearrangement control signal, the communication data of 1CH is correctly restored. This signal is input to the error correction decoding circuit 8, and the carrier sweep by AFC is continued until Viterbi is synchronized. At this time, the data of 2CH and 3CH are not synchronized because the rearrangement rules on the sending side are different, but when the carrier wave of 1CH is swept, the Viterbi is synchronized and the decoding is correctly performed. Output terminal 17
The AFC 14 is instructed to stop the carrier wave sweep by the signal from the AFC 14. The AFC 14 stops the sweep with the frequency and phase fixed. At the same time, the rearrangement control circuit 16 also receives the signal from the synchronization detection output terminal 17 and stops rearranging the signal sequence.

At this time, correct decoded data is output from the data output terminal 9.

In the embodiment of the present invention, the case where the Viterbi decoding system is used and the simple selection means by the data rearranging circuits 15 and 15 ^' is used has been described. However, the coding system or the decoding system and the circuit configuration are not limited to this. . Although the rearrangement is shown by the rearrangement of P and Q, it is also possible to adopt a method of dividing data into blocks.

In the embodiment of the present invention, for the sake of explanation, the rearrangement control circuit 16 is shown to be connected to the transmitting side and the receiving side in common by wired means. May be provided.

[0023]

Even if the AFC range is widened and the sweep range is widened, erroneous carrier wave sweeping can be prevented without increasing the transmission rate.

[Brief description of the drawings]

FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing data rearrangement control of the apparatus according to the embodiment of the present invention.

FIG. 3 is a diagram showing a communication data signal sequence in an AFC sweep range of the apparatus according to the embodiment of the present invention.

FIG. 4 is a diagram illustrating a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Data input terminal 2 Error correction coding circuit 3 Carrier drop-in part 4 Modulator 5 Data transmission terminal 6 Data reception terminal 7 Demodulator 8 Error correction decoding circuit 9 Data output terminal 10 Satellite 11 Carrier ID insertion circuit 12 Carrier ID identification circuit 13 Carrier ID control circuit 14 AFC 15, 15 ^' Data rearrangement circuit 16 Rearrangement control circuit 17 Synchronization detection output terminal

Claims (3)

(57) [Claims] A data input terminal for inputting communication data, an error correction encoding circuit for error correction encoding data input from the data input terminal, and communication data output from the error correction encoding circuit. A modulator for modulating,
A data transmission terminal for transmitting communication data modulated by the modulator; a data reception terminal for receiving the communication data transmitted from the data transmission terminal and arriving via a satellite; and a communication data from the data reception terminal. A satellite communication device comprising: a demodulator for demodulating; an error correction decoding circuit for error correcting and decoding the output of the demodulator; and a carrier pulling unit for pulling in a carrier for receiving the communication data. The unit is means for rearranging the order so that the communication data signal sequence of the adjacent carrier of the signal sequence of the communication data output from the error correction encoding circuit is different, and reorders the order output from the demodulator. Means for restoring a signal sequence of the communication data. 2. The satellite communication apparatus according to claim 1, wherein said rearranging unit includes a unit for rearranging two subsequent burst data signals with each other. 3. The error correction decoding circuit includes a synchronization detection output terminal, and the carrier drop-in unit includes means for fixing a reception frequency and a phase when a synchronization state is transmitted to the synchronization detection output terminal. 2. The satellite communication apparatus according to claim 1, wherein said rearranging unit includes a unit for stopping a rearranging operation when a synchronization state is transmitted to said synchronization detection output terminal.