JP6430898B2 - Transmission device for radio communication system and transmission method for radio communication system - Google Patents

Description

  The present invention relates to a transmission device for a wireless communication system and a transmission method for a wireless communication system.

  For example, in a wireless communication system, a plurality of antennas are used, a frequency band of a transmission signal is divided by the number of antennas, and signals of each divided frequency band (hereinafter also referred to as sub-spectrum) are transmitted by each antenna. There is a band division array that re-synthesizes the original transmission signal in space. Thereby, the radio | wireless communications system can improve EIRP (Equivalent Isotropic Radiated Power) according to the number of antennas irrespective of a modulation and a demodulation system.

  However, when a transmission signal of each sub-spectrum is transmitted by each antenna, a phase shift may occur between the sub-spectrums due to conversion processing to a transmission frequency such as a Ku band in a BUC (Block Up Converter). is there. Due to this phase shift, the wireless communication system may not obtain a desired EIRP.

  Therefore, the transmission signal phase between adjacent sub-spectrums is inverted, and the amplitude and phase in each sub-spectrum of the transmission signal are adjusted so that the signal power at the divided frequency of the re-synthesized transmission signal is minimized. And the technique which improves EIRP is proposed (for example, refer patent document 1, 2). Also, a step track control technique for improving the EIRP by changing the phase of the transmission signal of each sub-spectrum by a predetermined angle so as to maximize the signal power of the transmission signal of each sub-spectrum is proposed. (For example, refer to Patent Document 3).

JP 2013-48348 A JP 2014-207553 A JP 2013-27004 A

  A conventional wireless communication system needs to perform transmission / reception of a transmission signal multiple times in order to adjust the phase of the transmission signal of each sub-spectrum by monitoring the signal power of the transmission signal. That is, the conventional wireless communication system has a problem that it takes time until the phase of the transmission signal of each subspectrum is adjusted.

  In step track control, the phase of the transmission signal of the subspectrum is sequentially adjusted for each antenna, so that it takes time for adjustment as the number of antennas increases.

  An object of the present invention is to provide a transmission device of a wireless communication system and a transmission method of a wireless communication system that can adjust the phase of a transmission signal of each sub-spectrum in a shorter time than the prior art without depending on the number of antennas. And

The first invention adjusts the amplitude and phase of a transmission signal of a plurality of sub-spectrums using spectrum dividing means for dividing the spectrum of the transmission signal on the frequency axis into a plurality of sub-spectrums, and amplitude and phase calibration coefficients. Amplitude / phase adjustment means for inverting the phase of one of the frequency band transmission signals superimposed between adjacent sub-spectrums, and a plurality of amplitude signals adjusted by the amplitude / phase adjustment means a plurality of transmitters for transmitting sub spectrum transmission signals, respectively, among transmission signals transmitted spatial synthesized synthesized signal by multiple transmitters, the composite signal of the frequency band to be superimposed on each between the adjacent sub-spectrum a power acquisition unit for acquiring power, synthetic signal of the superimposed frequency bands obtained by the power acquisition unit With power, and a updating means for updating the calibration coefficients of the amplitude and phase for use in the amplitude and phase adjusting means, updating means, the minimum power of the combined signal of the frequency band to be superimposed on each between the adjacent sub-spectrum Calculate the offset phase angle that is the phase difference between the sub-spectrums, and add the offset phase angles calculated between all adjacent sub-spectrums between the reference sub-spectrum and the sub-spectrum to be updated The value is updated as the phase calibration coefficient of the transmission signal of the sub-spectrum to be updated .

The second aspect of the invention adjusts the amplitude and phase of a transmission signal of a plurality of sub-spectrums using a spectrum division process for dividing the spectrum of the transmission signal into a plurality of sub-spectrums on the frequency axis and a calibration coefficient of the amplitude and phase. an amplitude and phase adjustment processing the phase of the frequency band transmission signal Ru is inverted to either superposition of the frequency band transmission signal to be superimposed between the sub-spectrum adjacent plurality adjusted by amplitude and phase adjustment processing The power of the combined signal of the frequency band to be superimposed for each adjacent sub-spectrum is obtained from the transmission process for transmitting the transmission signals of each sub-spectrum and the combined signal obtained by spatially combining the transmission signals transmitted by the transmission process. a power acquisition process for, of the frequency band synthesis signal to be superimposed obtained by the power acquisition processing power Used, the running and updating process for updating the calibration coefficients of the amplitude and phase for use in the amplitude and phase adjustment process, in the update process, the power of the combined signal of the frequency band to be superimposed on each between the adjacent sub-spectrum minimizes Calculate the offset phase angle, which is the phase difference between sub-spectrums, and add the offset phase angle calculated between all adjacent sub-spectrums between the reference sub-spectrum and the sub-spectrum to be updated. It is updated as the calibration coefficient of the phase of the transmission signal of the sub-spectrum to be updated .

  The present invention can adjust the phase of the transmission signal of each sub-spectrum in a shorter time than the conventional one without depending on the number of antennas.

It is a figure which shows one Embodiment of the transmitter of a radio | wireless communications system. It is a figure which shows an example of the relationship between the spectrum of a transmission signal, and a sub spectrum. It is a figure which shows an example of the spectrum of the synthetic | combination signal by which the sub spectrum shown in FIG. 2 was spatially synthesized. It is a figure which shows an example of the transmission process in the transmitter of the radio | wireless communications system shown in FIG.

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

  FIG. 1 shows an embodiment of a transmission device of a wireless communication system.

  1 includes a modulator 10, a DFT (Discrete Fourier Transform) unit 20, n spectrum division circuits 30 (30 (1) -30 (n)), and n amplitudes. A phase adjustment circuit 40 (40 (1) -40 (n)) is included. The transmitting apparatus 200 includes n IDFT (Inverse Discrete Fourier Transform) units 50 (50 (1) -50 (n)), n transmitters 60 (60 (1) -60 (n)), and a receiver 70. And a spectrum analyzer 80.

  The modulator 10 generates a transmission signal including data to be transmitted based on a modulation method such as QPSK (Quadrature Phase Shift Keying), and outputs the generated transmission signal to the DFT unit 20.

  The DFT unit 20 performs a discrete Fourier transform process on the transmission signal received from the modulator 10 and calculates the spectrum of the transmission signal. The DFT unit 20 outputs the calculated spectrum of the transmission signal to each spectrum dividing circuit 30.

  The spectrum division circuit 30 passes the transmission signal of the sub-spectrum in the frequency band corresponding to the preset band division weighting coefficient CW (CW1-CWn) out of the spectrum of the received transmission signal. For example, the spectrum division circuit 30 includes a multiplier 31 that multiplies the spectrum of the received transmission signal by the band division weight coefficient CW. For example, in the case of the spectrum division circuit 30 (1), the multiplier 31 passes the transmission signal of the sub-spectrum corresponding to the band division weighting factor CW1 in the spectrum of the transmission signal. The spectrum division circuits 30 (2) -30 (n) also operate in the same manner as the spectrum division circuit 30 (1), and transmit sub-spectrum transmission signals in different frequency bands corresponding to the band division weighting factors CW2-CWn, respectively. Let it pass. That is, the spectrum division circuits 30 (1) -30 (n) operate as a cosine roll-off filter or the like, and divide the spectrum of the transmission signal into n sub-spectrums.

  Band division weight coefficient CW is stored in advance in a storage device such as a memory included in transmission device 200. Band division weighting factors CW1-CWn may be set so that the bandwidths of the sub-spectrums are the same, or may be set according to the transmission performance (ie, EIRP) of transmitter 60.

The amplitude / phase adjustment circuit 40 adjusts the amplitude and phase in the sub-spectrum of the transmission signal that has passed through the spectrum dividing circuit 30 using the calibration coefficient instructed by the spectrum analyzer 80. That is, the amplitude / phase adjustment circuit 40 uses the amplitude and phase calibration coefficients instructed from the spectrum analyzer 80 to change the amplitude and phase of the transmission signal of the sub-spectrum and the amplitude and phase of the transmission signal of the other sub-spectrum. And adjust to align with each other. A sub-spectrum transmission signal whose amplitude and phase are adjusted is transmitted via each transmitter 60, whereby a signal having the same spectrum as the spectrum of the transmission signal before transmission is spatially synthesized.

  In addition, the amplitude / phase adjustment circuit 40 inverts the phase of the transmission signal in any one of the frequency bands that are superimposed between the sub-spectrums adjacent to each other. The phase inversion processing by the amplitude / phase adjustment circuit 40 will be described with reference to FIG. Thereafter, the amplitude / phase adjustment circuit 40 outputs the processed sub-spectrum transmission signal to the IDFT unit 50. The amplitude / phase adjustment circuit 40 may be combined with the spectrum division circuit 30 by adjusting the band division weight coefficient CW.

  The IDFT unit 50 performs inverse discrete Fourier transform processing on the sub-spectrum transmission signal received from the amplitude / phase adjustment circuit 40, and converts it into a sub-spectrum transmission signal that changes in the time direction. The IDFT unit 50 outputs the converted sub-spectrum transmission signal to the transmitter 60.

  The transmitter 60 includes a power amplifier, a BUC (Block Up Converter), and the like, amplifies the power of the sub-spectrum transmission signal received from the IDFT unit 50, and sets the frequency of the sub-spectrum transmission signal to a transmission frequency such as Ku band. Convert to The transmitter 60 transmits a sub-spectrum transmission signal via an antenna included in the transmitter 60.

  The receiver 70 receives the sub-spectrum transmission signals transmitted by the respective transmitters 60 via the antennas of the receiver 70 as a spatially synthesized combined signal. In the case of satellite communication, the receiver 70 may receive a return signal from a communication satellite or the like as a composite signal.

  The spectrum analyzer 80 acquires the signal power of the synthesized signal in the frequency band that is superimposed on each other between adjacent sub-spectrums among the synthesized signals received by the receiver 70. The spectrum analyzer 80 updates the amplitude and phase calibration coefficients of the transmission signal of each sub-spectrum adjusted by the amplitude / phase adjustment circuit 40 using the acquired signal power of the combined signal of each frequency band. The operation of the spectrum analyzer 80 will be described with reference to FIG.

  FIG. 2 shows an example of the relationship between the spectrum of the transmission signal and the sub-spectrum. FIG. 2A shows the distribution of the spectrum SP of the transmission signal calculated by the discrete Fourier transform of the DFT unit 20 shown in FIG. FIG. 2B shows five sub-spectrums SB1 to SB5 obtained by dividing the spectrum SP of the transmission signal shown in FIG. 2A by, for example, five spectrum dividing circuits 30 for each division frequency f1-f4. . The five sub-spectrums SB1 to SB5 indicate frequency bandwidths according to the band division weighting factors CW1 to CW5 set so as to be divided at the respective division frequencies f1 to f4. Then, the set values of the band division weighting factors CW1 to CW5 are stored in the storage device of the transmission device 200.

  For example, the amplitude / phase adjustment circuit 40 inverts the phase of the transmission signal of the sub-spectrum SB2 by 180 degrees in the frequency band Δf1 overlapping each other between the adjacent sub-spectra SB1 and SB2 shown in FIG. Similarly to the frequency band Δf1, the amplitude / phase adjustment circuit 40 inverts the phase of each transmission signal of the sub-spectrums SB3-SB5 by 180 degrees for each of the frequency bands Δf2-Δf4. Note that the amplitude / phase adjustment circuit 40 may invert the phases of the transmission signals of the sub-spectrums SB1 to SB4 in the respective frequency bands Δf1 to Δf4. Further, by adjusting the values of the band division weighting factors CW1-CW5, each spectrum division circuit 30 may invert the phase of the transmission signal of the sub-spectrum SB2-SB5 in each frequency band Δf1-Δf4.

  FIG. 3 shows an example of a spectrum SP2 of a synthesized signal obtained by spatially synthesizing the sub-spectra SB1 to SB5 shown in FIG. In the spectrum SP2 of the composite signal, the phase of the transmission signal of the sub-spectrum SB2-SB5 in each frequency band Δf1-Δf4 is inverted, so the signal power of the composite signal in each frequency band Δf1-Δf4 is shown in FIG. It becomes smaller than the signal power of the spectrum SP of the transmission signal shown. When the amplitudes and phases of the transmission signals of the sub-spectrums SB1 to SB5 shown in FIG. 2B match each other, the signal power of the spectrum SP2 of the combined signal shows a minimum value at the division frequency f1 to f4.

  For example, the spectrum analyzer 80 performs DFT processing similar to that of the DFT unit 20 on the synthesized signal, and calculates the spectrum SP2 of the synthesized signal shown in FIG. The spectrum analyzer 80 acquires the signal power of the combined signal in the frequency band Δf1-Δf4 from the calculated spectrum SP2 of the combined signal, and monitors the signal power of the acquired combined signal in each frequency band Δf1-Δf4. The spectrum analyzer 80 then detects the phase difference between adjacent sub-spectrums so that the signal power of the synthesized signal of each frequency band Δf1−Δf4 (that is, the signal power at each divided frequency f1−f4) is minimized. An offset phase for compensating for is calculated.

For example, the spectrum analyzer 80 gives predetermined positive and negative deviations to the calibration coefficients of the amplitude and the offset phase angle, and sets the smaller signal power of the synthesized signal for each frequency band Δf1 to Δf4 to be monitored as new calibration coefficients. Step track control to calculate and update is executed. Alternatively, the spectrum analyzer 80 maintains the signal power of the combined signal at the minimum for each frequency band Δf1−Δf4 (that is, the phase difference between adjacent subspectrums is 0) and the offset phase angle. Calibration coefficients may be calculated and updated. Then, the spectrum analyzer 80 feeds back the updated amplitude and offset phase angle to each amplitude / phase adjustment circuit 40.

  Thus, the spectrum analyzer 80 can calculate in parallel the offset phase angle between adjacent sub-spectrums by monitoring the signal power of the combined signal in each frequency band Δf1-Δf4 in parallel. Then, the transmission apparatus 200 can adjust the phase of the transmission signal of each subspectrum in a shorter time than in the past.

The offset phase angle calculated by the spectrum analyzer 80 is a phase difference between adjacent sub-spectrums. Therefore, the spectrum analyzer 80 feeds back the offset phase angle added for each sub-spectrum using Equation (1) to each amplitude / phase adjustment circuit 40 as a phase calibration coefficient for the transmission signal of each sub-spectrum.

Δθ represents an offset phase angle calculated by the spectrum analyzer 80 in a frequency band that overlaps between adjacent sub-spectrums. θ is an offset phase angle with respect to the sub-spectrum transmission signal adjusted by the amplitude / phase adjustment circuit 40, and indicates a phase calibration coefficient. k is an integer from 2 to n. The offset phase angle θ1 with respect to the transmission signal of the sub-spectrum SB1 is set to 0 because it serves as a reference for the offset phase angle in the transmission signals of other sub-spectrums.

  Further, since the signal power of the combined signal is attenuated in frequency bands (for example, each frequency band Δf1-Δf4 shown in FIG. 3) superimposed between adjacent sub-spectrums, the transmission capacity of the transmission apparatus 200 is reduced. To do. Therefore, the transmitting apparatus 200 sets the width of the frequency band to be superimposed between adjacent sub-spectrums to be smaller than that of the spectrum SP2, and executes error correction processing on the composite signal, thereby degrading the C / N ratio during demodulation. May be avoided.

Further, for example, when the spectrum analyzer 80 does not execute the calibration of the amplitude and the offset phase angle, the amplitude / phase adjustment circuit 40 may select one of the sub-spectrums in the superposed frequency band among the transmission signals between the adjacent sub-spectrums. The phase of the transmission signal may not be inverted. Thereby, the transmission device 200 can avoid a decrease in communication capacity.

  FIG. 4 shows an example of transmission processing in the transmission apparatus 200 of the wireless communication system shown in FIG. The process illustrated in FIG. 4 is realized, for example, by executing a control program or the like stored in the storage device by a processor or the like included in the transmission device 200. Note that the processing illustrated in FIG. 4 may be executed by hardware provided in the transmission apparatus 200.

  In step S <b> 100, the modulator 10 generates a transmission signal including data to be transmitted based on a modulation scheme such as QPSK, and outputs the generated transmission signal to the DFT unit 20.

  In step S110, the DFT unit 20 performs a discrete Fourier transform process on the transmission signal generated in step S100, and calculates the spectrum of the transmission signal. The DFT unit 20 outputs the calculated spectrum of the transmission signal to each spectrum dividing circuit 30.

  In step S120, each spectrum division circuit 30 divides the spectrum of the received transmission signal into sub-spectrums corresponding to the band division weighting factor CW. The spectrum dividing circuit 30 outputs the divided sub-spectrum transmission signal to the amplitude / phase adjusting circuit 40.

  In step S130, the amplitude / phase adjustment circuit 40 adjusts the amplitude and phase of the sub-spectrum transmission signal divided in step S120.

  In step S140, the amplitude / phase adjustment circuit 40 inverts the phase of one of the transmission signals in the overlapping frequency band among the transmission signals between adjacent sub-spectrums. The amplitude / phase adjustment circuit 40 outputs the processed sub-spectrum transmission signal to the IDFT unit 50.

  In step S150, the IDFT unit 50 performs inverse discrete Fourier transform on the sub-spectrum transmission signal received from the amplitude / phase adjustment circuit 40, and converts it into a sub-spectrum transmission signal that changes in the time direction. The IDFT unit 50 outputs the converted sub-spectrum transmission signal to the transmitter 60.

  In step S <b> 160, the transmitter 60 transmits a transmission signal of each sub-spectrum via an antenna included in the transmitter 60.

  In step S170, the receiver 70 receives the sub-spectrum transmission signal transmitted by each transmitter 60 as a spatially synthesized composite signal.

  In step S180, the spectrum analyzer 80 uses the signal power in the frequency band that is superimposed for each adjacent subspectrum among the combined signals received in step S170, and uses the amplitude and offset phase angle Δθ for each adjacent subspectrum. Is calculated. For example, the spectrum analyzer 80 performs DFT processing on the synthesized signal and calculates the spectrum SP2 of the synthesized signal. The spectrum analyzer 80 acquires the signal power of the synthesized signal in the frequency band that is superimposed between adjacent sub-spectrums among the calculated spectrum SP2 of the synthesized signal. The spectrum analyzer 80 determines the amplitude for each adjacent sub-spectrum so that the signal power of the synthesized signal in each acquired frequency band (for example, the signal power at each divided frequency f1-f4 shown in FIG. 3) is minimized. And an offset phase Δθ for compensating for the phase difference is calculated.

  In step S190, the spectrum analyzer 80 determines whether or not the offset phase angle Δθ between all adjacent sub-spectrums has been calculated. When the spectrum analyzer 80 calculates the offset phase angle Δθ between all the sub-spectrums, the processing of the transmission device 200 moves to step S200. On the other hand, when the spectrum analyzer 80 has not calculated the offset phase angle Δθ between all the sub-spectrums, the processing of the transmission device 200 moves to step S180.

  In step S200, spectrum analyzer 80 calculates offset phase angle θ of the transmission signal of each subspectrum using offset phase angle Δθ for each adjacent subspectrum calculated in step S180 and equation (1).

  In step S210, the spectrum analyzer 80 determines whether or not the offset phase angle θ of the transmission signals of all sub-spectrums has been calculated. When the spectrum analyzer 80 calculates the offset phase angle Δθ of the transmission signals of all sub-spectrums, the processing of the transmission device 200 moves to step S220. On the other hand, when the spectrum analyzer 80 has not calculated the offset phase angle Δθ of the transmission signals of all sub-spectrums, the processing of the transmission device 200 moves to step S200.

In step S220, the spectrum analyzer 80 uses the amplitude calculated in step S180 and the offset phase angle θ of the transmission signal of each sub-spectrum calculated in step S200, and uses the amplitude and phase in each amplitude / phase adjustment circuit 40. Update the phase calibration factor.

  Then, the transmission device 200 repeatedly executes the processing from step S100 to step S220.

  As described above, in the embodiment shown in FIGS. 1 to 4, the amplitude / phase adjustment circuit 40 inverts the phase of the transmission signal in one of the overlapping frequency bands among the transmission signals between adjacent sub-spectrums. Let As a result, the combined signal received by the receiver 70 has the minimum signal power in each frequency band superimposed between adjacent sub-spectrums (that is, the signal power at each division frequency). The spectrum analyzer 80 acquires the signal power of the synthesized signal for each frequency band to be superimposed, and calculates the amplitude and the offset phase angle so that the signal power of the synthesized signal in each frequency band is kept to a minimum.

  That is, the spectrum analyzer 80 can calculate the offset phase angle Δθ for each adjacent sub-spectrum in parallel by monitoring in parallel the signal power of the combined signal of each frequency band superimposed between the adjacent sub-spectrums. Then, the spectrum analyzer 80 calculates the offset phase angle θ of the transmission signal of each sub-spectrum using the calculated offset phase angle Δθ for each adjacent sub-spectrum and Equation (1). Thereby, the transmission apparatus 200 can adjust the phase of the transmission signal of each sub-spectrum in a shorter time than in the past.

  From the above detailed description, features and advantages of the embodiments will become apparent. This is intended to cover the features and advantages of the embodiments described above without departing from the spirit and scope of the claims. Also, any improvement and modification should be readily conceivable by those having ordinary knowledge in the art. Therefore, there is no intention to limit the scope of the inventive embodiments to those described above, and appropriate modifications and equivalents included in the scope disclosed in the embodiments can be used.

DESCRIPTION OF SYMBOLS 10 ... Modulator; 20 ... DFT part; 30 (1) -30 (n) ... Spectrum division circuit; 31 ... Multiplier; 40 (1) -40 (n) ... Amplitude / phase adjustment circuit; 50 (n) ... IDFT part; 60 (1) -60 (n) ... transmitter; 70 ... receiver; 80 ... spectrum analyzer; 200 ... transmitting device; CW1-CWn ... band division weight coefficient; f1-f4 ... Division frequency; SP, SP2 ... Spectrum; SB1-SB5 ... Sub-spectrum

Claims (2)

Spectrum dividing means for dividing the spectrum of the transmission signal into a plurality of sub-spectrums on the frequency axis;
Using calibration coefficients of the amplitude and phase adjusts the amplitude and phase of a plurality of the sub-spectrum transmission signals, one of the superimposed frequency of the transmission signal of the frequency band that overlaps between the sub spectrum adjacent Amplitude / phase adjustment means for inverting the phase of the transmission signal in the band;
A plurality of transmitters for transmitting a transmission signal of a plurality of the sub-spectrum adjusted by said amplitude and phase adjusting means, respectively,
Of the composite signal transmitted signal transmitted is spatially combined by the transmitter of the multiple, the power acquisition unit that acquires the power of the combined signal of the frequency band that the superposition between every said sub-spectrum adjacent,
Update means for updating the calibration coefficient of the amplitude and phase used in the amplitude / phase adjustment means using the power of the combined signal of the superimposed frequency band acquired by the power acquisition means ,
The updating means calculates an offset phase angle that is a phase difference between the sub-spectrums that minimizes the power of the composite signal in the superimposed frequency band for each of the adjacent sub-spectrums, and the sub-spectrum serving as a reference An addition value obtained by adding the offset phase angles calculated between all adjacent sub-spectrums between the sub-spectrums to be updated is updated as the phase calibration coefficient of the transmission signal of the sub-spectrum to be updated.
Transmitting device of a wireless communication system comprising a call. Spectrum division processing for dividing the spectrum of the transmission signal into a plurality of sub-spectrums on the frequency axis;
Using calibration coefficients of the amplitude and phase adjusts the amplitude and phase of a plurality of the sub-spectrum transmission signals, one of the superimposed frequency of the transmission signal of the frequency band that overlaps between the sub spectrum adjacent and amplitude and phase adjustment processing phase Ru by inverting the band transmission signals,
A transmission process for transmitting conditioned by previous SL amplitude and phase adjustment processing the plurality of the sub-spectrum transmission signals, respectively,
Among the transmit synthesis signal transmission signal transmitted is spatially synthesized by the process, a power and acquires the power of the combined signal of the frequency band that the superposition between every said sub-spectrum adjacent,
And updating the used power frequency band synthesis signal to the obtained superimposed by the power acquisition process, for updating the calibration coefficients of the amplitude and phase used in the amplitude and phase adjustment processing
Run
In the update process, an offset phase angle that is a phase difference between the sub-spectrums that minimizes the power of the combined signal in the frequency band to be superimposed between adjacent sub-spectrums is calculated, and the sub-spectrum serving as a reference An addition value obtained by adding the offset phase angles calculated between all adjacent sub-spectrums between the sub-spectrums to be updated is updated as the phase calibration coefficient of the transmission signal of the sub-spectrum to be updated. A transmission method for a wireless communication system.

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