WO2013137222A1 - Satellite communication reception device and reception method - Google Patents
Satellite communication reception device and reception method Download PDFInfo
- Publication number
- WO2013137222A1 WO2013137222A1 PCT/JP2013/056726 JP2013056726W WO2013137222A1 WO 2013137222 A1 WO2013137222 A1 WO 2013137222A1 JP 2013056726 W JP2013056726 W JP 2013056726W WO 2013137222 A1 WO2013137222 A1 WO 2013137222A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- frequency
- frequency shift
- signal
- unit
- synchronization
- Prior art date
Links
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/1851—Systems using a satellite or space-based relay
- H04B7/18515—Transmission equipment in satellites or space-based relays
Definitions
- the present invention relates to a satellite communication receiving apparatus and a receiving method.
- a satellite communication system that transmits signals between earth stations via a communication satellite is known.
- a certain earth station transmits a signal to another earth station (receiving station)
- a frequency deviation caused by a transmitting station, a local transmitter of a communication satellite, etc. occurs.
- the frequency deviation exceeds the allowable deviation, the receiving station cannot receive the received signal.
- Patent Document 1 detects a phase difference from a signal delayed by a certain time with respect to the received signal, and averages the phase difference. Is an automatic frequency control circuit that corrects a frequency deviation of a received signal based on the received signal, and determines a received signal detection area based on a synchronization word (UW) included in the received signal, and receives based on the determined detected area An automatic frequency control circuit that corrects a frequency deviation when a signal is not correctly captured is disclosed.
- UW synchronization word
- the technique according to Patent Document 1 is premised on a demodulation operation by a delay detection method, and there is a problem that an effect cannot be obtained by a synchronous detection method widely used in fixed satellite communication. Further, since the technique according to Patent Document 1 corrects the frequency deviation of the received signal based on the synchronization word included in the received signal, it is applied when the received signal is a burst wave having no synchronization word. In the case where the received signal is a continuous wave, there is a problem that it is difficult to shorten the time until the establishment of reception synchronization due to the time for controlling the correction amount of the frequency deviation.
- the present invention has been made in view of the above circumstances, and is not limited to a specific detection method and reception wave, and can be used to expand a reception frequency range and shorten a time until establishment of reception synchronization and a satellite communication reception apparatus and reception. It aims to provide a method.
- a satellite communication receiver includes a receiving unit that receives a signal transmitted via a communication satellite, and a plurality of frequency shift circuits that shift the frequency of the signal received by the receiving unit with different frequency shift amounts.
- Each of the signals output from the plurality of frequency shift circuits includes synchronization processing means for performing synchronization processing, and selection means for selecting, as a reception signal, an output signal of the frequency shift circuit for which synchronization has been established by the synchronization processing means.
- the reception frequency range can be expanded and the time until establishment of reception synchronization can be shortened without being limited to a specific detection method and reception wave.
- FIG. 1 is a block diagram of a satellite communication system according to an embodiment of the present invention. It is a block diagram which shows schematic structure of the earth station shown in FIG.
- FIG. 3 is a block diagram of a receiving circuit of the modem device shown in FIG. 2.
- FIG. 4 is a block diagram of the IF sampling circuit shown in FIG. 3. It is a figure for demonstrating operation
- FIG. 4 is a block diagram of a carrier processing unit shown in FIG. 3.
- the satellite communication system 1000 includes a communication satellite 100 that is a space station and a plurality of earth stations 200, as shown in FIG.
- the earth station 200 includes a master station 210 and a plurality of slave stations (VSAT: Very Small Aperture Terminal) 221 to 22m (m is an integer of 2 or more).
- VSAT Very Small Aperture Terminal
- Each of the plurality of slave stations 221 to 22m and the master station 210 transmits and receives signals through the lines 30 and 40.
- the lines 30 and 40 connecting each of the plurality of slave stations 221 to 22m and the master station 210 are relayed via the communication satellite 100.
- the master station 210 is also called a HUB station, and performs setting / cancellation, monitoring, and control of the lines of the slave stations 221 to 22m.
- Each of the plurality of slave stations 221 to 22m is configured as a fixed station, a portable station, an in-vehicle station, and the like, and a line frequency is assigned to each of them by the control of the master station 210.
- a signal is transmitted from the master station 210 to each of the slave stations 221 to 22m by a TDM (Time Division Multiplexing) system via the line 30.
- a continuous wave is transmitted from the master station 210 to each of the slave stations 221 to 22m through the line 30.
- the line 30 is a communication line, a supervisory control line, a tracking line in the case where the slave station has an automatic acquisition function in the satellite direction, etc., and its application is not limited.
- the signals from each of the slave stations 221 to 22m to the master station 210 are transmitted by the TDMA (Time Division Multiple Access) system via the line 40.
- a burst wave is transmitted from each of the slave stations 221 to 22m to the master station 210 via the line 40.
- the line 40 may be used for a communication line, a monitoring line, or the like.
- the satellite communication system 1000 is configured as a TDM / TDMA system.
- the receiving circuit of the modem device included in the earth station 200 has a configuration unique to the present embodiment.
- This unique configuration can be applied to any earth station of the master station 210 and the plurality of slave stations 221 to 22m. Therefore, hereinafter, the configuration of a predetermined earth station among the master station 210 and the plurality of slave stations 221 to 22m will be described as the configuration of the earth station 200.
- the earth station 200 is configured as an earth station having a receiving circuit of a modem that can capture the direction of the communication satellite 100.
- the earth station 200 communicates with the master station 210 or the slave stations 221 to 22m via the communication satellite 100.
- the earth station 200 includes a directional antenna 20, an antenna control / drive unit 21, a high frequency transmission / reception unit 22, a modem device 23, and a terminal device 24.
- the antenna 20 tracks the communication satellite 100 and transmits / receives radio waves to / from the communication satellite 100 under the control of the antenna control / drive unit 21.
- the antenna control / drive unit 21 drives the antenna 20 in order to adjust the direction, polarization plane, and the like of the antenna 20.
- the antenna control / drive unit 21 directs the antenna 20 in the satellite direction based on the reception level and the reception synchronization information acquired from the modem 23.
- the high frequency transmission / reception unit 22 is a device that transmits and receives a high frequency (RF) signal, and is configured integrally with the antenna control / drive unit 21 or installed in the vicinity of the antenna control / drive unit 21.
- RF high frequency
- the modem 23 is connected to the high frequency transmitter / receiver 22 and supplies the reception level and the reception synchronization information to the antenna control / drive unit 21. Also, the modem 23 exchanges predetermined communication data with the terminal device 24.
- the transmission circuit of the modem device 23 is based on a known design.
- the receiving circuit 230 of the modem 23 includes a frequency conversion unit 1, an analog-digital conversion circuit (ADC) 2, an IF sampling circuit 3, a frequency shift unit 4, a carrier processing unit 5, and the like.
- the frequency shift unit 4, the carrier processing unit 5, the symbol memory unit 6, and the demodulation unit 7 operate under the control of the control unit 10.
- the frequency converter 1 converts the RF signal sent from the high-frequency transmitter / receiver 22 into an intermediate frequency (IF) signal, and includes a synthesizer 1a, a mixer 1b, and a low-pass filter 1c.
- the synthesizer 1a is for selecting a reception frequency band, and supplies a sine wave signal used for frequency conversion to the mixer 1b.
- the mixer 1b converts the RF signal from the high frequency transmitter / receiver 22 into an IF signal in the operating frequency band of the ADC 2 based on the sine wave signal from the synthesizer 1a. This IF signal is sent to the ADC 2.
- the synthesizer 1a is a sine wave signal having a local oscillation frequency fo corresponding to the difference between the frequency fr (t) of the signal in the high frequency band to be received and the operating frequency band (frequency in the sampling frequency band) fi of the ADC 2.
- (Local oscillation signal) So (t) is generated and supplied to the mixer 1b.
- the mixer 1b mixes the reception signal Sr (t) and the local oscillation signal So (t), and outputs signals having frequencies of (fr ⁇ fo) and (fr + fo).
- the low-pass filter 1c extracts an intermediate frequency (IF) band signal having a frequency of (fr-fo) and outputs an analog IF (intermediate frequency) signal Sr (t).
- the ADC 2 samples the analog IF signal Sr (t) sent from the frequency converter 1 at a predetermined sampling rate, converts it to a digital signal DSr (t), and sends it to the IF sampling circuit 3.
- the IF sampling circuit 3 frequency-converts the digital IF signal DSr (t) sent from the ADC 2 to generate a baseband signal. This baseband signal is sent to the frequency shift unit 4.
- the IF sampling circuit 3 includes, for example, a numerically controlled oscillator (NCO) 31, first and second mixers 32 and 33, and low-pass filters 34 and 35 as shown in FIG. Composed.
- NCO numerically controlled oscillator
- the NCO 31 generates orthogonal local oscillation signals sin ( ⁇ n) and cos ( ⁇ n).
- the first mixer 32 multiplies the digital IF signal DSr (t) by the local oscillation signal sin ( ⁇ n) and converts it into an I component baseband signal.
- the second mixer 33 multiplies the digital IF signal DSr (t) by the local oscillation signal cos ( ⁇ n) and converts it into a Q component baseband signal.
- the low-pass filter 34 removes the double frequency component contained in the I component baseband signal by limiting the high frequency band.
- the low pass filter 35 removes the double frequency component contained in the baseband signal of the Q component by limiting the high frequency band.
- the frequency shift unit 4 is a device that shifts the frequency of the signal received by the receiving means from the high frequency transmitting / receiving unit 22 to the IF sampling circuit 3.
- the frequency shift unit 4 includes a plurality of frequency shift circuits 41 to 4n (n is an integer of 2 or more). Each of the frequency shift circuits 41 to 4n shifts the frequency of the signal received by the receiving unit by a frequency shift amount different from that of other frequency shift circuits.
- the frequency shift amounts of the frequency shift circuits 41 to 4n are expressed as f1 to fn, respectively.
- the frequency shift amounts f1 to fn of the frequency shift circuits 41 to 4n are bands in which an assumed range of reception frequency deviation included in the baseband signal (a wider range than the pullable range determined by the modulation band of the received signal) is determined by the symbol rate.
- the frequency corresponds to each section when divided into n pieces for each width (withdrawable range). That is, in the frequency shift circuits 41 to 4n, the frequency shift amount is determined so that the shift interval becomes equal to the pullable range.
- the shift interval may be smaller than the pullable range.
- Each of the frequency shift circuits 41 to 4n includes an NCO 401, mixers 402 and 403, and low-pass filters 404 and 405, as illustrated in FIG.
- the mixer 402 multiplies the I component baseband signal and the local oscillation signal, and outputs an I component baseband signal shifted in frequency by fi.
- the mixer 403 multiplies the Q component baseband signal and the local oscillation signal, and outputs a Q component baseband signal whose frequency is shifted by fi.
- the low-pass filter 404 outputs only the low frequency side of the signal output from the mixer 402 to the carrier processing unit 5.
- the low-pass filter 405 outputs only the low frequency side of the signal output from the mixer 403 to the carrier processing unit 5.
- the baseband signal can be waited at n (plural) frequencies. For this reason, the allowable deviation of the reception frequency can be expanded.
- each frequency shift circuit 41 to 4n can perform processing in parallel, and the received signal of the received signal can be processed at a higher speed than the method of expanding the pullable frequency range by sweeping on the frequency axis by one frequency shift circuit. Pull-in is possible.
- the carrier processing unit 5 oversamples a plurality of baseband signals from each of the frequency shift circuits 41 to 4n in accordance with the symbol rate, adjusts the waveform shaping processing for limiting the channel band, and the signal power level to be constant.
- AGC Automatic-Gain-Control
- BTR Bit-Timing-Recovery
- the generated signal is stored in the symbol memory unit 6.
- the carrier processing unit 5 includes an input unit 51, an oversampling unit 52, a waveform shaping circuit 53, an AGC circuit 54, and a BTR unit 55, as shown in FIG.
- the input unit 51 takes in and outputs the output signals of the frequency shift circuits 41 to 4n and supplies them to the subsequent stage in a time division manner.
- the oversampling unit 52 oversamples the signal at a sampling frequency corresponding to the symbol rate of the transmission signal, in this example, the symbol rate of the transmission data of the center station and the symbol rate of the transmission wave of the satellite. .
- the waveform shaping circuit 53 shapes the waveform of the output signal of the oversampling unit 52 so as to remove the frequency component of the unnecessary reception band based on the band limitation of the channel of the received signal.
- the AGC circuit 54 adjusts the amplitude so that the power level of the signal becomes constant.
- the BTR unit 55 generates a clock serving as a bit timing reference from a signal whose power level is adjusted to be constant.
- the symbol memory unit 6 stores symbol data from the carrier processing unit 5 and is composed of n symbol memories 61 to 6n.
- the time-multiplexed baseband signal from the carrier processing unit 5 is stored in the symbol memories 61 to 6n for each channel whose frequency is shifted by each of the frequency shift circuits 41 to 4n constituting the frequency shift unit 4.
- the carrier processing unit 5 processes the output signal of the frequency shift circuit 4i and outputs the baseband signal and the clock timing generation signal (BTR).
- the demodulator 7 acquires time-multiplexed data from the symbol memory unit 6 and demodulates the acquired data.
- the demodulator 7 includes a continuous wave (CW) detector 71, a synchronization word (UW) detector 72, and a phase estimator 73. And a soft decision unit 74 and an AFC (Automatic Frequency Control) unit 75.
- CW continuous wave
- UW synchronization word
- AFC Automatic Frequency Control
- the phase estimation unit 73 estimates the carrier phase based on the UW pattern detected by the UW detection unit 72, the baseband signal stored in the symbol memory 6i, and the BTR.
- Soft decision unit 74 outputs a soft decision value of the demodulated data. That is, the soft decision unit 74 calculates a soft decision value for each bit of the baseband signal based on the carrier phase estimated by the phase estimation unit 73, the baseband signal stored in the symbol memory 6i, and the BTR. Ask.
- the AFC unit 75 obtains a phase rotation amount per symbol from a phase difference over a plurality of symbols of the received signal, and detects a frequency deviation.
- the demodulator 7 performs the above operation on the symbol memories 61 to 6n while switching i.
- the demodulator 7 performs demodulation operation in a time division manner and returns frequency deviation data indicating the frequency deviation detected by the AFC unit 75 to the frequency shift circuits 41 to 4n.
- the demodulator 7 determines whether synchronization is established from the soft decision value generated by the soft decision unit 74, the demodulation result of the CW detection unit, etc., and the synchronization establishment information indicating the discrimination result and the soft decision unit 74
- the generated soft decision value is output for each symbol memory 6i.
- the carrier processing unit 5, the symbol memory 6, and the demodulation unit 7 perform synchronization processing on each of the output signals of the frequency shift circuits 41 to 4n.
- the synchronization shift line determination unit 8 determines a shift line for which reception synchronization has been established based on the synchronization establishment information supplied from the demodulation unit 7 and notifies the line selection unit 9 of line selection information indicating the determination result. For example, assume that it is determined that synchronization is established for the baseband signal stored in the symbol memory 6i. At this time, the synchronous shift line determination unit 8 determines that the shift line processed by the frequency shift circuit 4 i is a shift line for which synchronization has been established, and outputs line selection information indicating i to the line selection unit 9.
- the line selection unit 9 extracts the received data of the shift line for which reception synchronization has been established from the time multiplexed data, transmits it to the decoding unit 11 as a soft decision signal, and notifies the control unit 10 of the number of the selected shift line. That is, the line selection unit 9 extracts only the received data of the normally received shift line based on the line selection information from the synchronous shift line determination unit 8 and sends only the received data to the decoding unit 11.
- the line selection information indicating the shift line number i is provided from the synchronous shift line determination unit 8 to the line selection unit 9.
- the line selection unit 9 outputs the soft signal generated based on the baseband signal stored in the symbol memory 6 i to the decoding unit 11.
- the line selector 9 discards the soft signals generated from the other symbol memories 61 to 6 (i ⁇ 1) and 6 (i + 1) to 6n. Further, the line selection unit 9 notifies the control unit 10 of the shift line number i.
- the synchronization shift line determination unit 8 and the line selection unit 9 select the output signal of any frequency shift circuit in which synchronization is established by the carrier processing unit 5 to the synchronization shift line determination unit 8. And output to the decoding unit 11.
- the control unit 10 is composed of a CPU (Central Processing Unit) ROM (Read Only Memory) or the like, and controls the operation of each unit by the CPU operating based on data and programs stored in the ROM or the like.
- CPU Central Processing Unit
- ROM Read Only Memory
- the control unit 10 instructs the frequency shift unit 4 to stop the function blocks related to the lines other than the shift line for which reception synchronization has been established, based on the shift line number notified from the line selection unit 9. Thereby, the operation of the circuit is unnecessarily suppressed and the power consumption of the circuit is suppressed.
- the control unit 10 causes the frequency shift unit 4 to operate only the frequency shift circuit 4i, so that other frequency shift circuits, that is, frequency
- the shift circuits 41 to 4 (i ⁇ 1) and 4 (i + 1) to 4n are instructed to be stopped.
- the control unit 10 instructs the carrier processing unit 5 to process only the output of the frequency shift circuit 4i.
- control unit 10 causes the symbol memory unit 6 to store only the symbol memory 6i, and stops the storage operation of other symbol memories, that is, the symbol memories 61 to 6 (i-1) and 6 (i + 1) to 6n. Instruct them to do so. Further, the control unit 10 instructs the demodulation unit 7 to process only the data in the symbol memory 6i.
- the frequency shift unit 4 operates the frequency shift circuit 4i in response to an instruction from the control unit 10, and pauses the other frequency shift circuits 41 to 4 (i-1) and 4 (i + 1) to 4n. Further, in response to an instruction from the control unit 10, the carrier processing unit 5 switches the internal state to a state where only the output of the frequency shift circuit 4i can be processed. In response to an instruction from the control unit 10, the symbol memory unit 6 stops the operation of symbol memories other than the symbol memory 6i. The symbol memory 6i stores a baseband signal generated from the output signal of the frequency shift circuit 4i by the carrier processing unit 5. Further, in response to an instruction from the control unit 10, the demodulation unit 7 processes only the data in the symbol memory 6i.
- the decoding unit 11 is based on the soft decision value generated from the baseband signal obtained from the normally received shift line sent from the line selection unit 9 and the error correction method used for the line 30 or 40. Decrypt.
- the signal decoded by the decoding unit 11 is sent to the data processing unit 12 as decoded data.
- the data processing unit 12 transmits the received data to the terminal device 24 shown in FIG. 2 in a form corresponding to the conversion to the terminal data format and the communication protocol.
- the frequency shift unit 4 can wait for a baseband signal at a plurality of frequencies. For this reason, as a result, the allowable deviation of the reception frequency can be increased. Further, since the frequency shift unit 4 can perform processing in parallel by each of the frequency shift circuits 41 to 4n, the frequency shift unit 4 is a method of expanding the pullable frequency range by sweeping on the frequency axis by one frequency shift circuit. In comparison, it is possible to pull in the received signal at high speed.
- the reception frequency deviation in the communication line is the sum of the transmission frequency deviation from the transmission earth station and the frequency deviation of the local oscillation circuit of the communication satellite.
- a voice band signal For example, in a satellite communication system, a voice band signal, a small amount of control signal
- the communication line is a narrow-band line and the reception frequency deviation is larger than that, the receiving earth station 200 cannot pull in the signal.
- the receiving circuit 230 according to the present embodiment it is possible to widen the pullable frequency range, and thus it is possible to maintain good reception accuracy.
- the main factor of the reception frequency deviation is the transmission frequency deviation of the transmitting station, it is not necessary to keep the transmission deviation of the transmitting station with higher precision than necessary. There is no need to provide a highly accurate reference signal source in the earth station. Therefore, the price of the earth station can be reduced.
- the receiving circuit 230 since the time until the establishment of reception synchronization can be shortened, a high-speed acquisition is possible in a system that performs acquisition in the satellite direction with determination of establishment of reception synchronization. Therefore, as a result, the time required to start the satellite line and the time required for re-acquisition can be shortened, and the satellite line can be quickly connected.
- the portions other than the frequency shift circuits 41 to 4n constituting the frequency shift unit 4 are realized by the time-division operation of the same circuit, so that the FPGA (Field-Programmable) is mainly used. It is possible to minimize the amount of increase in circuit capacity of digital elements such as Gate Array.
- the circuit configuration itself of the modem device 23 illustrated in FIG. 3 can be changed as needed.
- the circuit shown in FIG. 3 may be configured by a discrete circuit or a DSP (Digital Signal Processor) or the like.
- the line selection by the line selection unit 9 can be performed based on, for example, synchronization establishment information instead of the output of the synchronization shift line determination unit 8. That is, the soft decision value of the shift line determined to have established synchronization may be output to the decoding unit 11 and the control unit 10 may be notified of information about the shift line. In this case, the synchronous shift line determination unit 8 may be removed.
- the earth station 200 is not provided with the antenna control / drive unit 21, and the earth station 200 may not have an automatic satellite capturing function. Moreover, the earth station 200 may not have a transmission function but may have only a reception function. In these cases, as in the above embodiment, the reception frequency deviation can be increased and the satellite line can be quickly connected.
- 1000 satellite communication system 100 communication satellite, 200 earth station, 210 master station, 221-22m slave station, 30, 40 lines, 20 antennas, 21 antenna control / drive unit, 22 high frequency transmission / reception unit, 23 modulation / demodulation device, 24 terminal device , 230 receiver circuit, 1 frequency converter, 1a synthesizer, 1b mixer, 1c low pass filter, 2 ADC, 3 IF sampling circuit, 31 NCO, 32, 33 mixer, 34, 35 low pass filter, 4 frequency shift unit, 41 to 4n Frequency shift circuit, 401 NCO, 402, 403 mixer, 404, 405 low pass filter, 5 carrier processing unit, 51 input unit, 52 oversampling unit, 53 waveform shaping circuit, 54 AGC circuit, 55 BTR unit, 6 symbol Memory section, 61-6n symbol memory, 7 demodulator section, 71 CW detection section, 72 UW detection section, 73 phase estimation section, 74 soft decision section, 75 AFC section, 8 synchronous shift line determination section, 9 line selection section, 10 Control unit, 11 decoding unit, 12 data
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Astronomy & Astrophysics (AREA)
- Aviation & Aerospace Engineering (AREA)
- General Physics & Mathematics (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Circuits Of Receivers In General (AREA)
Abstract
Provided is a satellite communication reception device comprising the following: a reception means for receiving signals transmitted through a communication satellite; a plurality of frequency shift circuits (41-4n) for shifting the frequency of signals received by the reception means by different frequency shift amounts for each; a synchronization processing means for performing synchronization processing on the respective signals output by the frequency shift circuits (41-4n); and a line selection unit (9) for selecting, as the reception signals, the frequency shift circuit (41-4n) output signals for which synchronization was established by the synchronization means.
Description
本発明は、衛星通信受信装置及び受信方法に関する。
The present invention relates to a satellite communication receiving apparatus and a receiving method.
地球局間で通信衛星を介して信号を伝送する衛星通信システムが知られている。このシステムにおいて、ある地球局(送信局)が他の地球局(受信局)に信号を送信する際に、送信局、通信衛星の局部発信器等に起因する周波数偏差が生じ、この周波数偏差が周波数の許容偏差を超えた場合は、受信局は、受信信号の引き込みができなくなる。
A satellite communication system that transmits signals between earth stations via a communication satellite is known. In this system, when a certain earth station (transmitting station) transmits a signal to another earth station (receiving station), a frequency deviation caused by a transmitting station, a local transmitter of a communication satellite, etc. occurs. When the frequency deviation exceeds the allowable deviation, the receiving station cannot receive the received signal.
周波数の許容偏差を超える受信信号を引き込み可能とする技術として、特許文献1には、受信信号に対して一定時間だけ遅延させた信号との位相差を検出し、その位相差を平均化した信号に基づいて受信信号の周波数偏差を補正する自動周波数制御回路であって、受信信号に含まれる同期語(UW)に基づいて受信信号の検出領域を判断し、判断された検出領域に基づいて受信信号が正しく捕捉できでいない場合に、周波数偏差を補正する自動周波数制御回路が開示されている。
As a technique for enabling reception of a received signal that exceeds a frequency tolerance, Patent Document 1 detects a phase difference from a signal delayed by a certain time with respect to the received signal, and averages the phase difference. Is an automatic frequency control circuit that corrects a frequency deviation of a received signal based on the received signal, and determines a received signal detection area based on a synchronization word (UW) included in the received signal, and receives based on the determined detected area An automatic frequency control circuit that corrects a frequency deviation when a signal is not correctly captured is disclosed.
特許文献1に係る技術は、遅延検波方式による復調動作を前提としており、固定衛星通信で広く用いられている同期検波方式では効果が得られないという問題があった。また、特許文献1に係る技術は、受信信号に含まれる同期語に基づいて、受信信号の周波数偏差を補正するものであるため、受信信号が同期語を持たないバースト波である場合には適用できず、受信信号が連続波である場合には、周波偏差の補正量を制御する時間により、受信同期確立までの時間を短縮することが困難であるという問題もあった。
The technique according to Patent Document 1 is premised on a demodulation operation by a delay detection method, and there is a problem that an effect cannot be obtained by a synchronous detection method widely used in fixed satellite communication. Further, since the technique according to Patent Document 1 corrects the frequency deviation of the received signal based on the synchronization word included in the received signal, it is applied when the received signal is a burst wave having no synchronization word. In the case where the received signal is a continuous wave, there is a problem that it is difficult to shorten the time until the establishment of reception synchronization due to the time for controlling the correction amount of the frequency deviation.
本発明は、上記実状に鑑みてなされたものであり、特定の検波方法及び受信波に限られずに、受信周波数範囲の拡大と受信同期確立までの時間の短縮が可能な衛星通信受信装置及び受信方法を提供することを目的とする。
The present invention has been made in view of the above circumstances, and is not limited to a specific detection method and reception wave, and can be used to expand a reception frequency range and shorten a time until establishment of reception synchronization and a satellite communication reception apparatus and reception. It aims to provide a method.
本発明に係る衛星通信受信装置は、通信衛星を介して送信されてくる信号を受信する受信手段と、受信手段で受信した信号を、それぞれ異なる周波数シフト量で周波数シフトする複数の周波数シフト回路と、複数の周波数シフト回路が出力する信号のそれぞれについて、同期処理を行う同期処理手段と、同期処理手段により同期が確立した周波数シフト回路の出力信号を受信信号として選択する選択手段と、を備える。
A satellite communication receiver according to the present invention includes a receiving unit that receives a signal transmitted via a communication satellite, and a plurality of frequency shift circuits that shift the frequency of the signal received by the receiving unit with different frequency shift amounts. Each of the signals output from the plurality of frequency shift circuits includes synchronization processing means for performing synchronization processing, and selection means for selecting, as a reception signal, an output signal of the frequency shift circuit for which synchronization has been established by the synchronization processing means.
本発明によれば、特定の検波方法及び受信波に限られずに、受信周波数範囲の拡大と受信同期確立までの時間の短縮が可能である。
According to the present invention, the reception frequency range can be expanded and the time until establishment of reception synchronization can be shortened without being limited to a specific detection method and reception wave.
本発明の実施の形態に係る衛星通信システムについて図面を参照して説明する。
A satellite communication system according to an embodiment of the present invention will be described with reference to the drawings.
本実施の形態に係る衛星通信システム1000は、図1に示すように、宇宙局である通信衛星100と、複数の地球局200と、を備える。
The satellite communication system 1000 according to the present embodiment includes a communication satellite 100 that is a space station and a plurality of earth stations 200, as shown in FIG.
地球局200は、親局210と、複数の子局(VSAT:Very Small Aperture Terminal)221~22m(mは、2以上の整数)と、から構成される。複数の子局221~22m各々と親局210とは、回線30、40により信号を送受信する。複数の子局221~22m各々と親局210とを結ぶ回線30、40は、通信衛星100を介して中継される。
The earth station 200 includes a master station 210 and a plurality of slave stations (VSAT: Very Small Aperture Terminal) 221 to 22m (m is an integer of 2 or more). Each of the plurality of slave stations 221 to 22m and the master station 210 transmits and receives signals through the lines 30 and 40. The lines 30 and 40 connecting each of the plurality of slave stations 221 to 22m and the master station 210 are relayed via the communication satellite 100.
親局210は、HUB局とも呼ばれるものであり、各子局221~22mの回線の設定/解除、監視、制御を行う。複数の子局221~22m各々は、固定局、可搬局、車載局等として構成され、これら各々には親局210の制御によって回線の周波数が割り当てられる。
The master station 210 is also called a HUB station, and performs setting / cancellation, monitoring, and control of the lines of the slave stations 221 to 22m. Each of the plurality of slave stations 221 to 22m is configured as a fixed station, a portable station, an in-vehicle station, and the like, and a line frequency is assigned to each of them by the control of the master station 210.
親局210から各子局221~22mへは、回線30によりTDM(Time Division Multiplexing)方式で信号が伝送される。親局210から各子局221~22mには、回線30により連続波が送信される。回線30は、通信回線、監視制御回線、子局が衛星方向の自動捕捉機能を有する場合の追尾回線等であり用途が限定されるものではない。
A signal is transmitted from the master station 210 to each of the slave stations 221 to 22m by a TDM (Time Division Multiplexing) system via the line 30. A continuous wave is transmitted from the master station 210 to each of the slave stations 221 to 22m through the line 30. The line 30 is a communication line, a supervisory control line, a tracking line in the case where the slave station has an automatic acquisition function in the satellite direction, etc., and its application is not limited.
各子局221~22mから親局210への信号は、回線40によりTDMA(Time Division Multiple Access)方式で伝送される。各子局221~22mから親局210には、回線40によりバースト波が送信される。回線40も通信回線、監視回線等の用途は問わない。
The signals from each of the slave stations 221 to 22m to the master station 210 are transmitted by the TDMA (Time Division Multiple Access) system via the line 40. A burst wave is transmitted from each of the slave stations 221 to 22m to the master station 210 via the line 40. The line 40 may be used for a communication line, a monitoring line, or the like.
つまり、本実施形態に係る衛星通信システム1000は、TDM/TDMA方式のシステムとして構成されている。
That is, the satellite communication system 1000 according to the present embodiment is configured as a TDM / TDMA system.
衛星通信システム1000では、地球局200が備える変復調装置の受信回路が本実施形態に特有の構成を有する。この特有の構成は、親局210、複数の子局221~22mのいずれの地球局にも適用可能である。従って、以下では、親局210、複数の子局221~22mのうち所定の地球局の構成を地球局200の構成として説明する。
In the satellite communication system 1000, the receiving circuit of the modem device included in the earth station 200 has a configuration unique to the present embodiment. This unique configuration can be applied to any earth station of the master station 210 and the plurality of slave stations 221 to 22m. Therefore, hereinafter, the configuration of a predetermined earth station among the master station 210 and the plurality of slave stations 221 to 22m will be described as the configuration of the earth station 200.
地球局200は、図2に示すように、通信衛星100の方向を捕捉可能な変復調装置の受信回路を有する地球局として構成されている。地球局200は、通信衛星100を介して親局210又は子局221~22mと通信を行う。
As shown in FIG. 2, the earth station 200 is configured as an earth station having a receiving circuit of a modem that can capture the direction of the communication satellite 100. The earth station 200 communicates with the master station 210 or the slave stations 221 to 22m via the communication satellite 100.
地球局200は、指向性のあるアンテナ20と、アンテナ制御/駆動部21と、高周波送受信部22と、変復調装置23と、端末装置24と、を備える。
The earth station 200 includes a directional antenna 20, an antenna control / drive unit 21, a high frequency transmission / reception unit 22, a modem device 23, and a terminal device 24.
アンテナ20は、アンテナ制御/駆動部21の制御の下、通信衛星100を追尾し、通信衛星100と電波を送受信する。
The antenna 20 tracks the communication satellite 100 and transmits / receives radio waves to / from the communication satellite 100 under the control of the antenna control / drive unit 21.
アンテナ制御/駆動部21は、アンテナ20の方向、偏波面等を調整するためにアンテナ20を駆動する。アンテナ制御/駆動部21は、変復調装置23から取得した受信レベルと受信同期情報とに基づいて、アンテナ20を衛星方向に向ける。
The antenna control / drive unit 21 drives the antenna 20 in order to adjust the direction, polarization plane, and the like of the antenna 20. The antenna control / drive unit 21 directs the antenna 20 in the satellite direction based on the reception level and the reception synchronization information acquired from the modem 23.
高周波送受信部22は、高周波(RF)信号を送受信する装置であり、アンテナ制御/駆動部21と一体に構成されるか、アンテナ制御/駆動部21の近傍に設置される。
The high frequency transmission / reception unit 22 is a device that transmits and receives a high frequency (RF) signal, and is configured integrally with the antenna control / drive unit 21 or installed in the vicinity of the antenna control / drive unit 21.
変復調装置23は、高周波送受信部22と接続され、アンテナ制御/駆動部21に受信レベルと受信同期情報を供給する。また、変復調装置23は、端末装置24と所定の通信データのやり取りを行う。
The modem 23 is connected to the high frequency transmitter / receiver 22 and supplies the reception level and the reception synchronization information to the antenna control / drive unit 21. Also, the modem 23 exchanges predetermined communication data with the terminal device 24.
次に、変復調装置23が備える受信回路230について、図3を参照して説明する。なお、変復調装置23の送信回路は周知の設計による。
Next, the receiving circuit 230 provided in the modem device 23 will be described with reference to FIG. The transmission circuit of the modem device 23 is based on a known design.
変復調装置23の受信回路230は、図3に示すように、周波数変換部1と、アナログ-デジタル変換回路(ADC)2と、IFサンプリング回路3と、周波数シフト部4と、キャリア処理部5と、シンボルメモリ部6と、復調部7と、同期シフト回線判定部8と、回線選択部9と、制御部10と、復号部11と、データ処理部12と、を備える。なお、周波数シフト部4、キャリア処理部5、シンボルメモリ部6、復調部7各部は、制御部10の制御の下、動作する。
As shown in FIG. 3, the receiving circuit 230 of the modem 23 includes a frequency conversion unit 1, an analog-digital conversion circuit (ADC) 2, an IF sampling circuit 3, a frequency shift unit 4, a carrier processing unit 5, and the like. A symbol memory unit 6, a demodulation unit 7, a synchronous shift channel determination unit 8, a channel selection unit 9, a control unit 10, a decoding unit 11, and a data processing unit 12. The frequency shift unit 4, the carrier processing unit 5, the symbol memory unit 6, and the demodulation unit 7 operate under the control of the control unit 10.
周波数変換部1は、高周波送受信部22から送られたRF信号を中間周波数(IF)信号に変換するものであり、シンセサイザ1aと、ミキサ1bと、ローパスフィルタ1cとから構成される。シンセサイザ1aは、受信周波数帯を選択するためのものであり、周波数変換に用いられる正弦波信号をミキサ1bに供給する。ミキサ1bは、シンセサイザ1aからの正弦波信号に基づき、高周波送受信部22からのRF信号をADC2の動作周波数帯のIF信号に変換する。このIF信号は、ADC2に送られる。
The frequency converter 1 converts the RF signal sent from the high-frequency transmitter / receiver 22 into an intermediate frequency (IF) signal, and includes a synthesizer 1a, a mixer 1b, and a low-pass filter 1c. The synthesizer 1a is for selecting a reception frequency band, and supplies a sine wave signal used for frequency conversion to the mixer 1b. The mixer 1b converts the RF signal from the high frequency transmitter / receiver 22 into an IF signal in the operating frequency band of the ADC 2 based on the sine wave signal from the synthesizer 1a. This IF signal is sent to the ADC 2.
具体的には、シンセサイザ1aは、受信対象の高周波帯域の信号の周波数fr(t)とADC2の動作周波数帯(サンプリング周波数帯域の周波数)fiとの差に相当する局部発振周波数foの正弦波信号(局部発振信号)So(t)を生成し、ミキサ1bに供給する。ミキサ1bは、受信信号Sr(t)と局部発振信号So(t)を混合し、周波数が(fr-fo)と(fr+fo)の信号を出力する。ローパスフィルタ1cは、周波数が(fr-fo)の中間周波数(IF)帯域の信号を抽出し、アナログのIF(中間周波数)信号Sr(t)を出力する。
Specifically, the synthesizer 1a is a sine wave signal having a local oscillation frequency fo corresponding to the difference between the frequency fr (t) of the signal in the high frequency band to be received and the operating frequency band (frequency in the sampling frequency band) fi of the ADC 2. (Local oscillation signal) So (t) is generated and supplied to the mixer 1b. The mixer 1b mixes the reception signal Sr (t) and the local oscillation signal So (t), and outputs signals having frequencies of (fr−fo) and (fr + fo). The low-pass filter 1c extracts an intermediate frequency (IF) band signal having a frequency of (fr-fo) and outputs an analog IF (intermediate frequency) signal Sr (t).
ADC2は、周波数変換部1から送られたアナログのIF信号Sr(t)を所定のサンプリングレートでサンプリングしてデジタル信号DSr(t)に変換し、IFサンプリング回路3に送る。
The ADC 2 samples the analog IF signal Sr (t) sent from the frequency converter 1 at a predetermined sampling rate, converts it to a digital signal DSr (t), and sends it to the IF sampling circuit 3.
IFサンプリング回路3は、ADC2から送られたデジタルIF信号DSr(t)を周波数変換してベースバンド信号を生成する。このベースバンド信号は、周波数シフト部4に送られる。
The IF sampling circuit 3 frequency-converts the digital IF signal DSr (t) sent from the ADC 2 to generate a baseband signal. This baseband signal is sent to the frequency shift unit 4.
具体的には、IFサンプリング回路3は、例えば、図4に示すように、数値制御発振器(NCO:Numerical Controlled Oscillator)31と、第1と第2のミキサ32,33、ローパスフィルタ34,35から構成される。
Specifically, the IF sampling circuit 3 includes, for example, a numerically controlled oscillator (NCO) 31, first and second mixers 32 and 33, and low- pass filters 34 and 35 as shown in FIG. Composed.
NCO31は、直交する局部発振信号sin(ωn)とcos(ωn)を生成する。
The NCO 31 generates orthogonal local oscillation signals sin (ωn) and cos (ωn).
第1のミキサ32は、デジタルIF信号DSr(t)と局部発振信号sin(ωn)とを乗算し、I成分のベースバンド信号に変換する。第2のミキサ33は、デジタルIF信号DSr(t)と局部発振信号cos(ωn)とを乗算し、Q成分のベースバンド信号に変換する。
The first mixer 32 multiplies the digital IF signal DSr (t) by the local oscillation signal sin (ωn) and converts it into an I component baseband signal. The second mixer 33 multiplies the digital IF signal DSr (t) by the local oscillation signal cos (ωn) and converts it into a Q component baseband signal.
ローパスフィルタ34は、高周波帯域を制限することにより、I成分のベースバンド信号に含まれている倍周波成分を除去する。
The low-pass filter 34 removes the double frequency component contained in the I component baseband signal by limiting the high frequency band.
ローパスフィルタ35は、高周波帯域を制限することにより、Q成分のベースバンド信号に含まれている倍周波成分を除去する。
The low pass filter 35 removes the double frequency component contained in the baseband signal of the Q component by limiting the high frequency band.
こうして、I成分のベースバンド信号とQ成分のベースバンド信号とから構成される複素ベースバンド信号が出力される。
Thus, a complex baseband signal composed of an I component baseband signal and a Q component baseband signal is output.
周波数シフト部4は、高周波送受信部22~IFサンプリング回路3までの受信手段で受信した信号の周波数をシフトする装置である。周波数シフト部4は、複数の周波数シフト回路41~4n(nは、2以上の整数)を有している。周波数シフト回路41~4nは、それぞれ、受信手段で受信した信号の周波数を、他の周波数シフト回路とは異なった周波数シフト量で周波数シフトする。なお、以下の説明では、理解を容易にするため、周波数シフト回路41~4nの周波数シフト量を、それぞれ、f1~fnと表現する。
The frequency shift unit 4 is a device that shifts the frequency of the signal received by the receiving means from the high frequency transmitting / receiving unit 22 to the IF sampling circuit 3. The frequency shift unit 4 includes a plurality of frequency shift circuits 41 to 4n (n is an integer of 2 or more). Each of the frequency shift circuits 41 to 4n shifts the frequency of the signal received by the receiving unit by a frequency shift amount different from that of other frequency shift circuits. In the following description, for easy understanding, the frequency shift amounts of the frequency shift circuits 41 to 4n are expressed as f1 to fn, respectively.
周波数シフト回路41~4nの周波数シフト量f1~fnは、ベースバンド信号に含まれる受信周波数偏差の想定範囲(受信信号の変調帯域により定まる引き込み可能範囲よりも広い範囲)を、シンボルレートで定まる帯域幅(引き込み可能範囲)毎にn個に区切った場合の、各区分に相当する周波数となっている。つまり、周波数シフト回路41~4nは、シフト間隔が引き込み可能範囲と等しくなるように、周波数シフト量が定められている。
The frequency shift amounts f1 to fn of the frequency shift circuits 41 to 4n are bands in which an assumed range of reception frequency deviation included in the baseband signal (a wider range than the pullable range determined by the modulation band of the received signal) is determined by the symbol rate. The frequency corresponds to each section when divided into n pieces for each width (withdrawable range). That is, in the frequency shift circuits 41 to 4n, the frequency shift amount is determined so that the shift interval becomes equal to the pullable range.
例えば、受信周波数偏差の想定範囲がfaであり、シンボルレートで定まる帯域幅(引き込み可能範囲)がfa/4であるとする。このとき、n=4となり、周波数シフト回路41~44が配置される。この場合、周波数シフト回路41は、図5に示すように、ベースバンド信号の周波数を周波数シフト量f1=fa/8だけシフトしてキャリア処理部5に送出する。また、周波数シフト回路42は、ベースバンド信号の周波数を周波数シフト量f2=-fa/8だけシフトしてキャリア処理部5に送出する。また、周波数シフト回路43は、ベースバンド信号の周波数を周波数シフト量f3=3×fa/8だけシフトしてキャリア処理部5に送出する。また、周波数シフト回路44は、ベースバンド信号の周波数を周波数シフト量f4=-3×fa/8だけシフトしてキャリア処理部5に送出する。このようにして、周波数シフト部4は、同一回線を複数の周波数帯で受信することを可能とする。なお、シフト間隔は、引き込み可能範囲よりも小さくてもよい。
For example, assume that the assumed range of the reception frequency deviation is fa, and the bandwidth determined by the symbol rate (withdrawable range) is fa / 4. At this time, n = 4, and the frequency shift circuits 41 to 44 are arranged. In this case, as shown in FIG. 5, the frequency shift circuit 41 shifts the frequency of the baseband signal by the frequency shift amount f1 = fa / 8 and sends it to the carrier processing unit 5. Further, the frequency shift circuit 42 shifts the frequency of the baseband signal by the frequency shift amount f2 = −fa / 8 and sends it to the carrier processing unit 5. Further, the frequency shift circuit 43 shifts the frequency of the baseband signal by the frequency shift amount f3 = 3 × fa / 8 and sends it to the carrier processing unit 5. Further, the frequency shift circuit 44 shifts the frequency of the baseband signal by the frequency shift amount f4 = −3 × fa / 8 and sends it to the carrier processing unit 5. In this way, the frequency shift unit 4 can receive the same line in a plurality of frequency bands. The shift interval may be smaller than the pullable range.
周波数シフト回路41~4nは、それぞれ、図6に例示するように、NCO401と、ミキサ402、403と、ローパスフィルタ404、405とから構成される。
Each of the frequency shift circuits 41 to 4n includes an NCO 401, mixers 402 and 403, and low- pass filters 404 and 405, as illustrated in FIG.
周波数シフト回路4i(i=1~n)のNCO401は、周波数シフト量fi(i=1~n)に相当する周波数の局部発振信号を生成する。ミキサ402は、I成分のベースバンド信号と局部発振信号とを乗算して、周波数がfiだけシフトしたI成分のベースバンド信号を出力する。ミキサ403は、Q成分のベースバンド信号と局部発振信号とを乗算して、周波数がfiだけシフトしたQ成分のベースバンド信号を出力する。ローパスフィルタ404は、ミキサ402から出力された信号のうちの低周波側のみをキャリア処理部5に出力する。ローパスフィルタ405は、ミキサ403から出力された信号のうちの低周波側のみをキャリア処理部5に出力する。
The NCO 401 of the frequency shift circuit 4i (i = 1 to n) generates a local oscillation signal having a frequency corresponding to the frequency shift amount fi (i = 1 to n). The mixer 402 multiplies the I component baseband signal and the local oscillation signal, and outputs an I component baseband signal shifted in frequency by fi. The mixer 403 multiplies the Q component baseband signal and the local oscillation signal, and outputs a Q component baseband signal whose frequency is shifted by fi. The low-pass filter 404 outputs only the low frequency side of the signal output from the mixer 402 to the carrier processing unit 5. The low-pass filter 405 outputs only the low frequency side of the signal output from the mixer 403 to the carrier processing unit 5.
なお、周波数シフト回路4i(i=1~n)のNCO401は、後述する復調部7のAFC部75から周波数偏差fbiを受信した時には、周波数変位fbiを0にするように、例えば、局部信号の周波数fiをfi-fbiに修正する。この点は、後述する。
The NCO 401 of the frequency shift circuit 4i (i = 1 to n) receives the frequency deviation fbi from the AFC unit 75 of the demodulator 7 described later, so that the frequency displacement fbi is set to 0, for example, the local signal The frequency fi is corrected to fi-fbi. This point will be described later.
周波数シフト部4によれば、ベースバンド信号をn個(複数)の周波数で待ち受け可能となる。このため、受信周波数の許容偏差を拡大することができる。また、各周波数シフト回路41~4nは、同時並行的に処理が可能であり、一つの周波数シフト回路によって周波数軸上をスイープさせることで引き込み可能周波数範囲を広げる手法に比べ、高速に受信信号の引き込みが可能となる。
According to the frequency shift unit 4, the baseband signal can be waited at n (plural) frequencies. For this reason, the allowable deviation of the reception frequency can be expanded. In addition, each frequency shift circuit 41 to 4n can perform processing in parallel, and the received signal of the received signal can be processed at a higher speed than the method of expanding the pullable frequency range by sweeping on the frequency axis by one frequency shift circuit. Pull-in is possible.
キャリア処理部5では、周波数シフト回路41~4n各々からの複数のベースバンド信号をシンボルレートに応じてオーバーサンプリングすると共に、チャネル帯域制限の波形整形処理、信号の電力レベルが一定となるように調整するAGC(Automatic Gain Control)処理、ビット同期を取るためのBTR(Bit Timing Recovery)処理等が実行され、ビットタイミング誤差を補正した後に、時間多重されたベースバンド信号が生成される。生成された信号は、シンボルメモリ部6に格納される。
The carrier processing unit 5 oversamples a plurality of baseband signals from each of the frequency shift circuits 41 to 4n in accordance with the symbol rate, adjusts the waveform shaping processing for limiting the channel band, and the signal power level to be constant. AGC (Automatic-Gain-Control) processing, BTR (Bit-Timing-Recovery) processing for obtaining bit synchronization, and the like are executed, and after correcting the bit timing error, a time-multiplexed baseband signal is generated. The generated signal is stored in the symbol memory unit 6.
具体的には、キャリア処理部5は、図7に示すように、入力部51、オーバーサンプリング部52、波形整形回路53、AGC回路54、BTR部55、を備える。
Specifically, the carrier processing unit 5 includes an input unit 51, an oversampling unit 52, a waveform shaping circuit 53, an AGC circuit 54, and a BTR unit 55, as shown in FIG.
入力部51は、周波数シフト回路41~4nの出力信号を取り込みいったん蓄積し、時分割的に後段に供給する。
The input unit 51 takes in and outputs the output signals of the frequency shift circuits 41 to 4n and supplies them to the subsequent stage in a time division manner.
オーバーサンプリング部52は、送信信号のシンボルレート、この例では、センタ局の送信データのシンボルレートと衛星の送信波のシンボルレートとに応じて、それぞれに応じたサンプリング周波数で、信号をオーバーサンプリングする。
The oversampling unit 52 oversamples the signal at a sampling frequency corresponding to the symbol rate of the transmission signal, in this example, the symbol rate of the transmission data of the center station and the symbol rate of the transmission wave of the satellite. .
波形整形回路53は、受信信号のチャネルの帯域制限に基づいて、受信不要帯域の周波数成分を除去するように、オーバーサンプリング部52の出力信号の波形を整形する。
The waveform shaping circuit 53 shapes the waveform of the output signal of the oversampling unit 52 so as to remove the frequency component of the unnecessary reception band based on the band limitation of the channel of the received signal.
AGC回路54は、信号の電力レベルが一定となるように、その振幅を調整する。
The AGC circuit 54 adjusts the amplitude so that the power level of the signal becomes constant.
BTR部55は、電力レベルが一定に調整された信号から、ビットタイミング基準となるクロックを生成する。
The BTR unit 55 generates a clock serving as a bit timing reference from a signal whose power level is adjusted to be constant.
シンボルメモリ部6は、キャリア処理部5からのシンボルデータを蓄えるものであり、n個のシンボルメモリ61~6nから構成される。キャリア処理部5からの時間多重されたベースバンド信号は、周波数シフト部4を構成する周波数シフト回路41~4n各々によって周波数がシフトされたチャネル毎に、シンボルメモリ61~6nに格納される。具体的には、シンボルメモリ6i(i=1~n)は、キャリア処理部5が、周波数シフト回路4iの出力信号を処理して出力したベースバンド信号とクロックタイミング生成用信号(BTR)とを記憶する。
The symbol memory unit 6 stores symbol data from the carrier processing unit 5 and is composed of n symbol memories 61 to 6n. The time-multiplexed baseband signal from the carrier processing unit 5 is stored in the symbol memories 61 to 6n for each channel whose frequency is shifted by each of the frequency shift circuits 41 to 4n constituting the frequency shift unit 4. Specifically, in the symbol memory 6i (i = 1 to n), the carrier processing unit 5 processes the output signal of the frequency shift circuit 4i and outputs the baseband signal and the clock timing generation signal (BTR). Remember.
復調部7は、シンボルメモリ部6から時間多重データを取得し、取得したデータを復調するものであり、連続波(CW)検出部71、同期語(UW)検出部72と、位相推定部73と、軟判定部74と、AFC(Automatic Frequency Control)部75と、を有する。
The demodulator 7 acquires time-multiplexed data from the symbol memory unit 6 and demodulates the acquired data. The demodulator 7 includes a continuous wave (CW) detector 71, a synchronization word (UW) detector 72, and a phase estimator 73. And a soft decision unit 74 and an AFC (Automatic Frequency Control) unit 75.
CW(Continuous Wave)検出部71は、シンボルメモリ部6の各シンボルメモリ6i(i=1~n)に蓄積されている一連のベースバンド信号とBTRとから、受信波が連続波であるか否かを検出する。即ち、CW検出部71は、シンボルメモリ6iに格納されているベースバンド信号が、連続的に出力されている信号であるか、一時的に出力されている信号であるかを判別する。さらに、CW検出部71は、連続波であると判別した場合は、BTRに基づいて、1フレーム内の復調処理を行い、そうでない場合(つまり、受信波がバースト波の場合)は、BTRに基づいて、1バースト内の復調処理を行う。CW検出部71は、シンボルメモリ6i(i=1~n)を切り替えながら、順次この動作を行う。
A CW (Continuous Wave) detection unit 71 determines whether or not the received wave is a continuous wave from a series of baseband signals and BTR stored in each symbol memory 6 i (i = 1 to n) of the symbol memory unit 6. To detect. That is, the CW detection unit 71 determines whether the baseband signal stored in the symbol memory 6i is a signal that is continuously output or a signal that is temporarily output. Further, if the CW detection unit 71 determines that the wave is a continuous wave, the CW detection unit 71 performs demodulation processing within one frame based on the BTR. If not (that is, if the received wave is a burst wave), Based on this, demodulation processing within one burst is performed. The CW detection unit 71 sequentially performs this operation while switching the symbol memory 6i (i = 1 to n).
UW検出部72は、シンボルメモリ部6のシンボルメモリ6i(i=1~n)に蓄積されている一連のベースバンド信号中に配置されているユニークワード(UW)パターンを検出する。
The UW detection unit 72 detects a unique word (UW) pattern arranged in a series of baseband signals stored in the symbol memory 6i (i = 1 to n) of the symbol memory unit 6.
位相推定部73は、UW検出部72が検出したUWパターンと、シンボルメモリ6iに蓄積されているベースバンド信号とBTRとに基づいて、キャリア位相を推定する。
The phase estimation unit 73 estimates the carrier phase based on the UW pattern detected by the UW detection unit 72, the baseband signal stored in the symbol memory 6i, and the BTR.
軟判定部74は、復調データの軟判定値を出力する。即ち、軟判定部74は、位相推定部73で推定されたキャリア位相と、シンボルメモリ6iに蓄積されているベースバンド信号とBTRとに基づいて、ベースバンド信号の各ビットについて、軟判定値を求める。
Soft decision unit 74 outputs a soft decision value of the demodulated data. That is, the soft decision unit 74 calculates a soft decision value for each bit of the baseband signal based on the carrier phase estimated by the phase estimation unit 73, the baseband signal stored in the symbol memory 6i, and the BTR. Ask.
AFC部75は、受信信号の複数シンボルに渡る位相差から1シンボル当たりの位相回転量を求め、周波数偏差を検出する。
The AFC unit 75 obtains a phase rotation amount per symbol from a phase difference over a plurality of symbols of the received signal, and detects a frequency deviation.
復調部7は、iを切り替えながら、上述の動作を、シンボルメモリ61~6nについて行う。復調部7は、復調動作を時分割で行う他、AFC部75で検出した周波数偏差を示す周波数偏差データを、各周波数シフト回路41~4nに返す。周波数シフト部4の各周波数シフト回路4i(i=1~n)は、AFC部75から通知された周波数偏差データに基づいて、周波数偏差が0になるように、NCO401の局部信号の周波数を調整(補正)する。例えば、周波数偏差がfbの場合には、局部発振信号fiの周波数を-fbする。但し、ここでの周波数偏差データは、各周波数シフト回路41~4nで区切られた引き込み可能範囲内に制限されることになる。復調部7は、軟判定部74が生成した軟判定値、CW検出部の復調結果、等から同期が確立しているか否かを判別し、判別結果を示す同期確立情報と軟判定部74が生成した軟判定値とを、各シンボルメモリ6iについて出力する。
The demodulator 7 performs the above operation on the symbol memories 61 to 6n while switching i. The demodulator 7 performs demodulation operation in a time division manner and returns frequency deviation data indicating the frequency deviation detected by the AFC unit 75 to the frequency shift circuits 41 to 4n. Each frequency shift circuit 4i (i = 1 to n) of the frequency shift unit 4 adjusts the frequency of the local signal of the NCO 401 based on the frequency deviation data notified from the AFC unit 75 so that the frequency deviation becomes zero. (to correct. For example, when the frequency deviation is fb, the frequency of the local oscillation signal fi is -fb. However, the frequency deviation data here is limited within the pullable range delimited by the frequency shift circuits 41 to 4n. The demodulator 7 determines whether synchronization is established from the soft decision value generated by the soft decision unit 74, the demodulation result of the CW detection unit, etc., and the synchronization establishment information indicating the discrimination result and the soft decision unit 74 The generated soft decision value is output for each symbol memory 6i.
こうして、キャリア処理部5、シンボルメモリ6、及び復調部7は、周波数シフト回路41~4nの出力信号のそれぞれについて、同期処理を行う。
Thus, the carrier processing unit 5, the symbol memory 6, and the demodulation unit 7 perform synchronization processing on each of the output signals of the frequency shift circuits 41 to 4n.
同期シフト回線判定部8は、復調部7から供給された同期確立情報に基づいて、受信同期の確立したシフト回線を判定し、その判定結果を示す回線選択情報を、回線選択部9へ通知する。例えば、シンボルメモリ6iに格納されているベースバンド信号について、同期が確立していると判別されたとする。このとき、同期シフト回線判定部8は、周波数シフト回路4iが処理したシフト回線が、同期が確立したシフト回線であると判別し、iを示す回線選択情報を回線選択部9に出力する。
The synchronization shift line determination unit 8 determines a shift line for which reception synchronization has been established based on the synchronization establishment information supplied from the demodulation unit 7 and notifies the line selection unit 9 of line selection information indicating the determination result. . For example, assume that it is determined that synchronization is established for the baseband signal stored in the symbol memory 6i. At this time, the synchronous shift line determination unit 8 determines that the shift line processed by the frequency shift circuit 4 i is a shift line for which synchronization has been established, and outputs line selection information indicating i to the line selection unit 9.
回線選択部9は、時間多重データから受信同期が確立したシフト回線の受信データを抜き出し、復号部11に軟判定信号として伝達すると共に、選択したシフト回線の番号を制御部10に通知する。即ち、回線選択部9は、同期シフト回線判定部8からの回線選択情報に基づいて、正常に受信したシフト回線の受信データのみを抽出し、復号部11にその受信データのみを送る。
The line selection unit 9 extracts the received data of the shift line for which reception synchronization has been established from the time multiplexed data, transmits it to the decoding unit 11 as a soft decision signal, and notifies the control unit 10 of the number of the selected shift line. That is, the line selection unit 9 extracts only the received data of the normally received shift line based on the line selection information from the synchronous shift line determination unit 8 and sends only the received data to the decoding unit 11.
例えば、同期シフト回線判定部8から、回線選択部9に対し、シフト回線番号iを示す回線選択情報が提供されたとする。このとき、回線選択部9は、シンボルメモリ6iに格納されているベースバンド信号に基づいて生成した軟信号を復号部11に出力する。そして、回線選択部9は、他のシンボルメモリ61~6(i-1)、6(i+1)~6nから生成された軟信号を破棄する。さらに、回線選択部9は、シフト回線番号iを制御部10に通知する。
For example, it is assumed that the line selection information indicating the shift line number i is provided from the synchronous shift line determination unit 8 to the line selection unit 9. At this time, the line selection unit 9 outputs the soft signal generated based on the baseband signal stored in the symbol memory 6 i to the decoding unit 11. Then, the line selector 9 discards the soft signals generated from the other symbol memories 61 to 6 (i−1) and 6 (i + 1) to 6n. Further, the line selection unit 9 notifies the control unit 10 of the shift line number i.
このように、同期シフト回線判定部8と回線選択部9とは、キャリア処理部5~同期シフト回線判定部8は、同期処理部より同期が確立したいずれかの周波数シフト回路の出力信号を選択して復号部11に出力する。
As described above, the synchronization shift line determination unit 8 and the line selection unit 9 select the output signal of any frequency shift circuit in which synchronization is established by the carrier processing unit 5 to the synchronization shift line determination unit 8. And output to the decoding unit 11.
制御部10は、CPU(Central Processing Unit)ROM(Read Only Memory)等から構成され、ROM等に格納されたデータ、プログラムに基づいてCPUが動作することで、前記各部の動作を制御する。
The control unit 10 is composed of a CPU (Central Processing Unit) ROM (Read Only Memory) or the like, and controls the operation of each unit by the CPU operating based on data and programs stored in the ROM or the like.
制御部10は、回線選択部9から通知されたシフト回線の番号に基づいて、受信同期の確立したシフト回線以外の回線に係る機能ブロックの停止を周波数シフト部4に指示する。これにより、不必要に回路の動作を抑制し、回路の消費電力を抑えている。具体的には、制御部10は、回線選択部9から通知されたシフト回線番号がiの場合、周波数シフト部4に、周波数シフト回路4iのみを動作させ、他の周波数シフト回路、すなわち、周波数シフト回路41~4(i-1)、4(i+1)~4nの動作を停止させるよう指示する。また、制御部10は、キャリア処理部5に、周波数シフト回路4iの出力のみを処理するよう指示する。また、制御部10は、シンボルメモリ部6に、シンボルメモリ6iのみ記憶動作させ、他のシンボルメモリ、すなわち、シンボルメモリ61~6(i-1)、6(i+1)~6nの記憶動作を停止させるよう指示する。また、制御部10は、復調部7に、シンボルメモリ6iのデータのみを処理するよう指示する。
The control unit 10 instructs the frequency shift unit 4 to stop the function blocks related to the lines other than the shift line for which reception synchronization has been established, based on the shift line number notified from the line selection unit 9. Thereby, the operation of the circuit is unnecessarily suppressed and the power consumption of the circuit is suppressed. Specifically, when the shift line number notified from the line selection unit 9 is i, the control unit 10 causes the frequency shift unit 4 to operate only the frequency shift circuit 4i, so that other frequency shift circuits, that is, frequency The shift circuits 41 to 4 (i−1) and 4 (i + 1) to 4n are instructed to be stopped. In addition, the control unit 10 instructs the carrier processing unit 5 to process only the output of the frequency shift circuit 4i. Further, the control unit 10 causes the symbol memory unit 6 to store only the symbol memory 6i, and stops the storage operation of other symbol memories, that is, the symbol memories 61 to 6 (i-1) and 6 (i + 1) to 6n. Instruct them to do so. Further, the control unit 10 instructs the demodulation unit 7 to process only the data in the symbol memory 6i.
周波数シフト部4は、制御部10からの指示に応答して、周波数シフト回路4iを動作させるともに、他の周波数シフト回路41~4(i-1)、4(i+1)~4nを休止させる。また、キャリア処理部5は、制御部10からの指示に応答して、内部の状態を、周波数シフト回路4iの出力のみを処理可能な状態に切り替える。シンボルメモリ部6は、制御部10からの指示に応答して、シンボルメモリ6i以外のシンボルメモリの動作を停止させる。シンボルメモリ6iは、キャリア処理部5が周波数シフト回路4iの出力信号から生成したベースバンド信号を記憶する。また、復調部7は、制御部10からの指示に応答して、シンボルメモリ6iのデータのみを処理する。
The frequency shift unit 4 operates the frequency shift circuit 4i in response to an instruction from the control unit 10, and pauses the other frequency shift circuits 41 to 4 (i-1) and 4 (i + 1) to 4n. Further, in response to an instruction from the control unit 10, the carrier processing unit 5 switches the internal state to a state where only the output of the frequency shift circuit 4i can be processed. In response to an instruction from the control unit 10, the symbol memory unit 6 stops the operation of symbol memories other than the symbol memory 6i. The symbol memory 6i stores a baseband signal generated from the output signal of the frequency shift circuit 4i by the carrier processing unit 5. Further, in response to an instruction from the control unit 10, the demodulation unit 7 processes only the data in the symbol memory 6i.
復号部11は、回線選択部9から送られた正常に受信したシフト回線で得られたベースバンド信号から生成された軟判定値と、回線30又は40に使用されている誤り訂正方式に基づいて復号する。この復号部11で復号された信号は復号データとしてデータ処理部12に送られる。
The decoding unit 11 is based on the soft decision value generated from the baseband signal obtained from the normally received shift line sent from the line selection unit 9 and the error correction method used for the line 30 or 40. Decrypt. The signal decoded by the decoding unit 11 is sent to the data processing unit 12 as decoded data.
データ処理部12は、図2に示す端末装置24等に、端末データ形式への変換、通信プロトコルに対応した形態で、受信データを伝達する。
The data processing unit 12 transmits the received data to the terminal device 24 shown in FIG. 2 in a form corresponding to the conversion to the terminal data format and the communication protocol.
以上の構成からなる変復調装置23の受信回路230では、周波数シフト部4によって、ベースバンド信号を複数の周波数で待ち受け可能となる。このため、結果的に受信周波数の許容偏差の拡大を図ることができる。また、周波数シフト部4では、各周波数シフト回路41~4nにより、同時並行的に処理が可能であるため、一つの周波数シフト回路によって周波数軸上をスイープさせることで引き込み可能周波数範囲を広げる手法に比べ、高速に受信信号の引き込みが可能となる。
In the receiving circuit 230 of the modulation / demodulation device 23 configured as described above, the frequency shift unit 4 can wait for a baseband signal at a plurality of frequencies. For this reason, as a result, the allowable deviation of the reception frequency can be increased. Further, since the frequency shift unit 4 can perform processing in parallel by each of the frequency shift circuits 41 to 4n, the frequency shift unit 4 is a method of expanding the pullable frequency range by sweeping on the frequency axis by one frequency shift circuit. In comparison, it is possible to pull in the received signal at high speed.
通信回線での受信周波数偏差は、送信地球局からの送信周波数偏差と、通信衛星の局所発振回路の周波数偏差の合計となるが、例えば、衛星通信システムで、音声帯域の信号、少量の制御信号等を伝送する場合、通信回線が狭帯域回線となり、それに比較して、受信周波数偏差が大きい場合は、受信側の地球局200で信号の引き込みができなくなる。このような場合であっても、本実施形態に係る受信回路230によれば、引き込み可能周波数範囲を広げることができるため、受信精度を良好に保つことができる。
The reception frequency deviation in the communication line is the sum of the transmission frequency deviation from the transmission earth station and the frequency deviation of the local oscillation circuit of the communication satellite. For example, in a satellite communication system, a voice band signal, a small amount of control signal When the communication line is a narrow-band line and the reception frequency deviation is larger than that, the receiving earth station 200 cannot pull in the signal. Even in such a case, according to the receiving circuit 230 according to the present embodiment, it is possible to widen the pullable frequency range, and thus it is possible to maintain good reception accuracy.
また、受信周波数偏差の主要因が送信局の送信周波数偏差である場合は、送信局の送信偏差を必要以上に高精度に保つ必要はなくなるため、あえて、高精度な周波数偏差を実現するための高精度な基準信号源を地球局に設ける必要はなくなる。したがって、地球局の低価格化が実現できる。
In addition, when the main factor of the reception frequency deviation is the transmission frequency deviation of the transmitting station, it is not necessary to keep the transmission deviation of the transmitting station with higher precision than necessary. There is no need to provide a highly accurate reference signal source in the earth station. Therefore, the price of the earth station can be reduced.
また、受信回路230によれば受信同期確立までの時間を短縮できるため、受信同期確立の判定を持って衛星方向の捕捉を行うようなシステムにおいては、高速捕捉が可能となる。したがって、結果的に衛星回線の開始までの時間、再捕捉時に要する時間を短縮でき、迅速な衛星回線の導通が可能となる。
Further, according to the receiving circuit 230, since the time until the establishment of reception synchronization can be shortened, a high-speed acquisition is possible in a system that performs acquisition in the satellite direction with determination of establishment of reception synchronization. Therefore, as a result, the time required to start the satellite line and the time required for re-acquisition can be shortened, and the satellite line can be quickly connected.
また、本実施形態の受信回路230の構成では、周波数シフト部4を構成する周波数シフト回路41~4n以外の部分については、同一回路の時分割動作により実現するため、主にFPGA(Field-Programmable Gate Array)等のデジタル素子の回路容量の増加量を必要最低限に抑えることが可能である。
Further, in the configuration of the receiving circuit 230 of the present embodiment, the portions other than the frequency shift circuits 41 to 4n constituting the frequency shift unit 4 are realized by the time-division operation of the same circuit, so that the FPGA (Field-Programmable) is mainly used. It is possible to minimize the amount of increase in circuit capacity of digital elements such as Gate Array.
なお、本発明は上記の実施形態及び図面によって限定されるものではない。適宜変更(構成要素の削除も含む)を加えることができる。
In addition, this invention is not limited by said embodiment and drawing. Changes can be made as appropriate (including deletion of components).
例えば、図3に例示する変復調装置23の回路構成自体は、必要に応じて、適宜変更可能である。また、図3に示す回路をディスクリート回路で構成しても、DSP(Digital Signal Processor)等で構成してもよい。また、回線選択部9による回線選択を、同期シフト回線判定部8の出力ではなく、例えば、同期確立情報に基づいて行うことも可能である。即ち、同期を確立したと判別されたシフト回線の軟判定値を復号部11に出力し、制御部10にそのシフト回線の情報を通知するようにしてもよい。この場合、同期シフト回線判定部8を除去してもよい。
For example, the circuit configuration itself of the modem device 23 illustrated in FIG. 3 can be changed as needed. Also, the circuit shown in FIG. 3 may be configured by a discrete circuit or a DSP (Digital Signal Processor) or the like. In addition, the line selection by the line selection unit 9 can be performed based on, for example, synchronization establishment information instead of the output of the synchronization shift line determination unit 8. That is, the soft decision value of the shift line determined to have established synchronization may be output to the decoding unit 11 and the control unit 10 may be notified of information about the shift line. In this case, the synchronous shift line determination unit 8 may be removed.
地球局200にアンテナ制御/駆動部21が設けられず、地球局200が自動衛星捕捉機能を有していなくてもよい。また、地球局200は、送信機能を有さず、受信機能のみを有していてもよい。これらの場合においても、上記実施形態と同様、受信周波数偏差の拡大と、迅速に衛星回線の導通が可能である。
The earth station 200 is not provided with the antenna control / drive unit 21, and the earth station 200 may not have an automatic satellite capturing function. Moreover, the earth station 200 may not have a transmission function but may have only a reception function. In these cases, as in the above embodiment, the reception frequency deviation can be increased and the satellite line can be quickly connected.
上記実施の形態は、いずれも本発明の趣旨の範囲内で各種の変形が可能である。上記実施の形態は本発明を説明するためのものであり、本発明の範囲を限定することを意図したものではない。本発明の範囲は実施形態よりも添付した請求項によって示される。請求項の範囲内、および発明の請求項と均等の範囲でなされた各種変形は本発明の範囲に含まれる。
Any of the above embodiments can be variously modified within the scope of the gist of the present invention. The above embodiments are for explaining the present invention, and are not intended to limit the scope of the present invention. The scope of the invention is indicated by the appended claims rather than the embodiments. Various modifications made within the scope of the claims and within the scope equivalent to the claims of the invention are included in the scope of the present invention.
本出願は、2012年3月14日に出願された、明細書、特許請求の範囲、図、および要約書を含む日本国特許出願2012-057479号に基づく優先権を主張するものである。この元となる特許出願の開示内容は参照により全体として本出願に含まれる。
This application claims priority based on Japanese Patent Application No. 2012-057479 filed on March 14, 2012, including the specification, claims, figures, and abstract. The disclosure of this original patent application is hereby incorporated by reference in its entirety.
1000 衛星通信システム、100 通信衛星、200 地球局、210 親局、221~22m 子局、30、40 回線、20 アンテナ、21 アンテナ制御/駆動部、22 高周波送受信部、23 変復調装置、24 端末装置、230 受信回路、1 周波数変換部、1a シンセサイザ、1b ミキサ、1c ローパスフィルタ、2 ADC、3 IFサンプリング回路、31 NCO、32、33 ミキサ、34、35 ローパスフィルタ、4 周波数シフト部、41~4n 周波数シフト回路、401 NCO、402、403 ミキサ、404、405 ローパスフィルタ、5 キャリア処理部、51 入力部、52 オーバーサンプリング部、53 波形整形回路、54 AGC回路、55 BTR部、6 シンボルメモリ部、61~6n シンボルメモリ、7 復調部、71 CW検出部、72 UW検出部、73 位相推定部、74 軟判定部、75 AFC部、8 同期シフト回線判定部、9 回線選択部、10 制御部、11 復号部、12 データ処理部。
1000 satellite communication system, 100 communication satellite, 200 earth station, 210 master station, 221-22m slave station, 30, 40 lines, 20 antennas, 21 antenna control / drive unit, 22 high frequency transmission / reception unit, 23 modulation / demodulation device, 24 terminal device , 230 receiver circuit, 1 frequency converter, 1a synthesizer, 1b mixer, 1c low pass filter, 2 ADC, 3 IF sampling circuit, 31 NCO, 32, 33 mixer, 34, 35 low pass filter, 4 frequency shift unit, 41 to 4n Frequency shift circuit, 401 NCO, 402, 403 mixer, 404, 405 low pass filter, 5 carrier processing unit, 51 input unit, 52 oversampling unit, 53 waveform shaping circuit, 54 AGC circuit, 55 BTR unit, 6 symbol Memory section, 61-6n symbol memory, 7 demodulator section, 71 CW detection section, 72 UW detection section, 73 phase estimation section, 74 soft decision section, 75 AFC section, 8 synchronous shift line determination section, 9 line selection section, 10 Control unit, 11 decoding unit, 12 data processing unit.
Claims (8)
- 通信衛星を介して送信されてくる信号を受信する受信手段と、
前記受信手段で受信した信号を、それぞれ異なる周波数シフト量で周波数シフトする複数の周波数シフト回路と、
前記複数の周波数シフト回路が出力する信号のそれぞれについて、同期処理を行う同期処理手段と、
前記同期処理手段により同期が確立した周波数シフト回路の出力信号を受信信号として選択する選択手段と、を備える、
衛星通信受信装置。 Receiving means for receiving a signal transmitted via a communication satellite;
A plurality of frequency shift circuits for frequency-shifting the signals received by the receiving means by different frequency shift amounts;
Synchronization processing means for performing synchronization processing for each of the signals output from the plurality of frequency shift circuits;
Selecting means for selecting, as a received signal, an output signal of the frequency shift circuit whose synchronization is established by the synchronization processing means,
Satellite communication receiver. - 前記選択手段は、同期が確立した出力信号を生成した周波数シフト回路以外の周波数シフト回路の動作を停止させる手段を備える、
請求項1に記載の衛星通信受信装置。 The selection means includes means for stopping the operation of a frequency shift circuit other than the frequency shift circuit that generated the output signal with which synchronization is established,
The satellite communication receiver according to claim 1. - 前記選択手段は、前記同期処理手段に、同期が確立した出力信号を生成した周波数シフト回路以外の周波数シフト回路の出力信号についての同期処理を停止させる手段を備える、
請求項1又は2に記載の衛星通信受信装置。 The selection unit includes a unit that causes the synchronization processing unit to stop synchronization processing for an output signal of a frequency shift circuit other than the frequency shift circuit that generates the output signal with which synchronization is established.
The satellite communication receiver according to claim 1 or 2. - 前記同期処理手段は、前記複数の周波数シフト回路の出力からそれぞれベースバンド信号を生成する処理と生成したベースバンド信号を復調する復調処理とを時分割で実行し、各周波数シフト回路の出力について同期が確立したか否かを判別する、
請求項1乃至3のいずれか1項に記載の衛星通信受信装置。 The synchronization processing means executes processing for generating a baseband signal from outputs of the plurality of frequency shift circuits and demodulation processing for demodulating the generated baseband signal in a time division manner, and synchronizes the outputs of the frequency shift circuits. Determine whether or not
The satellite communication receiving device according to any one of claims 1 to 3. - 前記同期処理手段は、各周波数シフト回路の信号について、周波数偏差を求め、求めた周波数偏差を、対応する周波数シフト回路にフィードバックし、
各周波数シフト回路は、フィードバックされた周波数偏差に基づいて、周波数シフト量を調整する、
請求項1乃至4のいずれか1項に記載の衛星通信受信装置。 The synchronization processing means obtains a frequency deviation for the signal of each frequency shift circuit, and feeds back the obtained frequency deviation to the corresponding frequency shift circuit.
Each frequency shift circuit adjusts the amount of frequency shift based on the fed back frequency deviation.
The satellite communication receiver according to any one of claims 1 to 4. - 前記複数の周波数シフト回路のシフト間隔は、変調帯域により定まる引き込み可能範囲以下である、
請求項1乃至5のいずれか1項に記載の衛星通信受信装置。 The shift interval of the plurality of frequency shift circuits is less than or equal to the pullable range determined by the modulation band,
The satellite communication receiver according to any one of claims 1 to 5. - 前記受信手段は、受信高周波信号から中間周波数帯のベースバンド信号を生成する手段を備える、
請求項1乃至6のいずれか1項に記載の衛星通信受信装置。 The receiving means includes means for generating a baseband signal of an intermediate frequency band from the received high-frequency signal.
The satellite communication receiver according to any one of claims 1 to 6. - 信号を受信し、
受信した信号を複数の信号に分けるとともに、前記複数の信号をそれぞれ異なる周波数シフト量で周波数シフトし、
周波数シフトした前記複数の信号それぞれについて同期処理を行うとともに、同期処理を行った前記複数の信号それぞれについて受信同期が確立しているか否かを判別し、
前記複数の信号のうちの受信同期が確立していると判別された信号を選択して出力する、
受信方法。 Receive the signal,
The received signal is divided into a plurality of signals, and the plurality of signals are frequency shifted by different frequency shift amounts,
Performing synchronization processing for each of the plurality of signals shifted in frequency and determining whether reception synchronization has been established for each of the plurality of signals subjected to synchronization processing;
Selecting and outputting a signal determined to have established reception synchronization among the plurality of signals;
Receiving method.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2012057479 | 2012-03-14 | ||
JP2012-057479 | 2012-03-14 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2013137222A1 true WO2013137222A1 (en) | 2013-09-19 |
Family
ID=49161128
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2013/056726 WO2013137222A1 (en) | 2012-03-14 | 2013-03-12 | Satellite communication reception device and reception method |
Country Status (1)
Country | Link |
---|---|
WO (1) | WO2013137222A1 (en) |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009182837A (en) * | 2008-01-31 | 2009-08-13 | Mitsubishi Electric Corp | Demodulator |
WO2010021041A1 (en) * | 2008-08-21 | 2010-02-25 | 富士通株式会社 | Receiver and receiving method |
JP2010219935A (en) * | 2009-03-17 | 2010-09-30 | Mitsubishi Electric Corp | Receiver |
-
2013
- 2013-03-12 WO PCT/JP2013/056726 patent/WO2013137222A1/en active Application Filing
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009182837A (en) * | 2008-01-31 | 2009-08-13 | Mitsubishi Electric Corp | Demodulator |
WO2010021041A1 (en) * | 2008-08-21 | 2010-02-25 | 富士通株式会社 | Receiver and receiving method |
JP2010219935A (en) * | 2009-03-17 | 2010-09-30 | Mitsubishi Electric Corp | Receiver |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
RU2450472C1 (en) | Synchronisation of ofdm symbols using preamble with frequency-shifted prefix and suffix for dvr-t2 receiver | |
EP0618687B1 (en) | Phase correction for radio receiver based an training sequence | |
EP2184867B1 (en) | Wireless communication device with improved synchronous timing detection of different base stations | |
US20050094750A1 (en) | Demodulation apparatus and method for reducing time delay of on-channel repeater in terrestrial digital TV broadcasting system | |
JP2009105558A (en) | Signal processing device, control method of signal processing device, digital broadcast receiving device, and control method of digital broadcast receiving device | |
US7577219B2 (en) | Apparatus for communications | |
JPH1065605A (en) | Receiving method, timing detecting device and receiving device | |
JP2000253446A (en) | Base station device and frame synchronization acquiring method | |
JP4842159B2 (en) | Frame synchronization apparatus, OFDM transmission / reception apparatus, and frame synchronization method | |
JP2001308762A (en) | Receiver for digital broadcasting | |
KR19980024230A (en) | Data signal timing correction device, filter device and portable wireless communication terminal device | |
EP0722230B1 (en) | TDMA system receiver for intermittently receiving burst data | |
WO2013137222A1 (en) | Satellite communication reception device and reception method | |
JP2013106270A (en) | Communication system, control method of communication system, and adaptive array wireless device | |
JP2010141866A (en) | Base station device | |
JP7283741B2 (en) | Receiver, Reception Method, and Reception Processing Program | |
JP2009089061A (en) | Receiver, and frequency hopping synchronization method | |
JP2009081701A (en) | Reception control method and receiver | |
JP5516318B2 (en) | Demodulator | |
JP2008311809A (en) | Frame synchronizing device and control method thereof | |
JP4907890B2 (en) | OFDM transmitter | |
JP6806497B2 (en) | Polarization shared converter, receiver and satellite receiver | |
JP4467397B2 (en) | Frequency control apparatus, radio communication apparatus, and frequency control method | |
JP6330174B2 (en) | Frequency offset estimation apparatus and radio communication apparatus | |
JP2013153242A (en) | Base station |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 13760402 Country of ref document: EP Kind code of ref document: A1 |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 13760402 Country of ref document: EP Kind code of ref document: A1 |
|
NENP | Non-entry into the national phase |
Ref country code: JP |