JP2013219571A - Relay device and relay system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To have a function to multiplex a plurality of user channels contained in an input spectrum without reproducing.SOLUTION: An exchange part 107 has: a spectrum division part 106 which inputs an input spectrum 103 and divides it into a plurality of sub-spectra 214; a plurality of output ports 221; and a plurality of sub-spectrum multiplex parts 231 corresponding to the plurality of output ports 221. The relay device includes the exchange part 107 and a spectrum coupling part 109. In the exchange part 107, each of the sub-spectrum multiplex parts 231 inputs the plurality of sub-spectra 214, at least some of the sub-spectra of the plurality of input sub-spectra 214 are multiplexed to generate one multiplex sub-spectrum 215, and the generated sub-spectrum 215 is output to a corresponding output port 221. In the spectrum coupling part 109, the plurality of multiplex sub-spectrum 215 output from the plurality of output ports 221 are coupled to generate an output spectrum.

Description

  The present invention relates to a satellite-mounted repeater mounted on, for example, an artificial satellite (communication satellite). The present invention relates to multiple access of repeaters that perform spectrum division / combination and frequency conversion using digital signal processing.

  The communication satellite receives a communication signal from the earth station on the ground, divides the spectrum of the communication signal by a filter, performs frequency conversion of the divided spectrum, and sends it to the ground. In order to perform this frequency conversion more flexibly, a satellite-mounted repeater that performs spectrum division / combination and frequency conversion in digital signal processing is desired.

  Conventionally, both digitally transponded and digitally regenerative functions are provided within the all digital satellite payload, transponded and regenerative functions. Are combined with a common digital platform to improve the overall efficiency and functionality of the satellite (see Patent Document 1).

Special table 2006-516867 JP2007-166424-A Special table 2008-072219 Special table 2008-124665

  A communication signal received by a satellite is converted from an analog signal to a digital signal by performing AD (Analog-to-Digital) conversion, the spectrum is divided by digital signal processing, and the order of the spectrum in units of cut out spectrums The digital signal processing function to send the communication signal to the ground by converting the continuous spectrum to one continuous band, and converting the continuous spectrum to DA (Digital-to-Analog). Since the conventional satellite relay station does not have a multiple access function at the satellite relay station and does not have a function for multiplexing frequencies mapped at different frequencies, the frequency use efficiency is high. There is a problem of deterioration.

  Further, the multiple access function in the conventional satellite is based on a regenerative relay system as shown in Patent Document 1, and there is a problem that a communication signal received by a satellite relay station cannot be multiplexed without being reproduced. is there.

  The present invention, for example, in a repeater mounted on a communication satellite, improves the frequency utilization efficiency by multiplexing and multiplexing a plurality of user channels included in an input signal without regenerating the communication signal. The purpose is to improve quality.

The repeater according to the present invention is
An input section for inputting an input spectrum;
A spectrum dividing unit that divides the input spectrum input by the input unit into a plurality of sub-spectra;
An exchange unit comprising a plurality of output ports and a plurality of subspectral multiplexing units corresponding to the plurality of output ports, wherein each subspectral multiplexing unit inputs the plurality of subspectra divided by the spectrum dividing unit. Multiplex at least a part of sub-spectrums of the plurality of input sub-spectrums to generate one multi-sub-spectrum, and output the generated multi-sub-spectra to a corresponding output port of the plurality of output ports. An exchange,
A spectrum combining unit configured to combine a plurality of the multiple sub-spectrums output from the plurality of output ports to generate an output spectrum;

  The repeater according to the present invention, for example, can multiplex a plurality of user channels included in the input spectrum of the input signal without reproducing, thereby improving frequency use efficiency and increasing the gain and bandwidth of the multiple channels. By controlling the above, there is an effect that the quality of the wireless communication signal can be improved.

3 is a functional block diagram (payload block diagram) of repeater 500 according to Embodiment 1. FIG. It is a figure which shows the spectrum division | segmentation function of the spectrum division part 106 of the repeater 500 which concerns on Embodiment 1. FIG. It is a figure which shows the spectrum coupling | bonding function of the spectrum coupling | bond part 109 of the repeater 500 which concerns on Embodiment 1. FIG. It is a figure which shows the exchange function of the exchange part 107 of the repeater 500 which concerns on Embodiment 1. FIG. 6 is a diagram illustrating a subspectral multiplexing function of a subspectral multiplexing unit 231 according to Embodiment 1. FIG. It is a functional block diagram for showing the effect of implementation of repeater 500 concerning Embodiment 1. FIG. 10 is a diagram illustrating an effect of implementation of a subspectral multiplexing unit 231 according to Embodiment 1. It is a functional block diagram for demonstrating the effect of the multiple access system of the repeater 500 and the repeater 500 which concerns on Embodiment 2. FIG. 10 is a functional block diagram of a repeater 501 according to Embodiment 3. FIG. It is a functional block diagram for demonstrating the effect of the multiple access system of the repeater 501 and the repeater 501 which concerns on Embodiment 3. FIG. FIG. 10 is a functional block diagram of a repeater 502 according to a fourth embodiment. FIG. 10 is a functional block diagram for explaining the effect of the repeater 502 and the multiple access method of the repeater 502 according to the fourth embodiment. FIG. 10 is a functional block diagram for explaining the effect of the repeater 502 and the multiple access method of the repeater 502 according to the fifth embodiment. FIG. 10 is a functional block diagram of a relay system 800 according to a sixth embodiment.

Embodiment 1 FIG.
The repeater 500 according to the present embodiment is, for example, a repeater (transponder) mounted on a communication satellite. The repeater (trasponder) receives an input signal from the earth station received by the antenna (receiver) provided in the communication satellite, converts the frequency of the input signal, and sends it to the ground as an output signal.

  FIG. 1 is a functional block diagram of repeater 500 according to the present embodiment. The functional configuration of repeater 500 according to the present embodiment will be described using FIG.

  The repeater 500 includes an AD conversion unit 105 (ADC: Analog-to-Digital Controller), a spectrum division unit 106, an exchange unit 107 (switch unit, subspectral multiplexing unit), a spectrum combining unit 109, and a DA conversion unit 110 (DAC). : Digital-to-Analog Controller) and a multiple access control unit 400.

  The repeater 500 receives the input spectrum 103. The input spectrum 103 is an input signal (not shown) spectrum from the satellite antenna. In the present embodiment, the input spectrum 103 is input with a plurality of input spectra 103 of 103a to 103n. For example, if a communication satellite has a plurality of antennas (14 antennas a to n), a plurality of input spectra 103a to 103n are input from a plurality of input ports. Similarly, a plurality of output spectra 104a to 104n are output from the plurality of output ports toward the satellite antenna.

  Hereinafter, the description of “input spectrum 103” may mean the entire input spectrum 103a to 103n, and may mean the input spectrum 103a to 103n, or a part of the input spectrum 103a to 103n, respectively. . The same applies to other functional blocks having subscripts attached to the codes (the AD conversion unit 105, the spectrum division unit 106, the spectrum combination unit 109, the DA conversion unit 110, and the subspectral multiplexing unit 231 (see FIG. 4)).

  The repeater 500 includes AD conversion units 105a to 105n and spectrum division units 106a to 106n in units of input spectra 103a to 103n. The repeater 500 includes spectrum coupling units 109a to 109n and DA conversion units 110a to 110n in units of output spectra 104a to 104n.

  The AD conversion units 105a to 105n are examples of input units that digitally convert and input the input spectra 103a to 103n. The AD conversion units 105a to 105n input the input spectra 103a to 103n, perform analog-digital conversion, and digitize the input spectra 103a to 103n. Hereinafter, subscripts (a to n) may be omitted.

  Spectrum dividing section 106 (FIG. 1) (106 a to 106 n) divides input spectrum 103 (103 a to 103 n) into a plurality of sub-spectrums with a frequency bandwidth serving as a division unit, and outputs the sub-spectrum to switching section 107. To do.

FIG. 2 is a diagram showing a spectrum dividing function of spectrum dividing section 106 of repeater 500 according to the present embodiment.
The spectrum dividing unit 106 uses the digital filter to divide the input spectrum 103 input from the AD conversion unit 105 (input unit) into a plurality of sub-spectrums 214 (214-1 to 214-m) with a frequency bandwidth that is a unit of division. , M is a natural number).
For example, the spectrum dividing unit 106a divides the input spectrum 103a including the input signals 201, 202, and 203 into sub-spectra 214a-1 to sub-spectrum 214a-m. Further, the spectrum dividing unit 106b divides the input spectrum 103b into sub-spectrum 214b-1 to sub-spectrum 214b-m.

The switching unit 107 (FIG. 1) performs switching in units of subspectrums divided by the spectrum dividing unit 106 in order to map the input signal included in the input spectrum 103 to an arbitrary frequency of the arbitrary output spectrum 104. The sub-spectrum is output to the spectrum combining unit 109.

Spectrum combining section 109 (FIG. 1) (109a to 109n) combines the sub-spectra output from switching section 107 and outputs the output spectrum to DA converting section 110 (110a to 110n).

FIG. 3 is a diagram illustrating a spectrum combining function of the spectrum combining unit 109 of the repeater 500 according to the present embodiment.
The spectrum combining unit 109 (109a to 109n) combines the sub-spectrum 215-1 to sub-spectrum 215-m output from the switching unit 107, converts the sub-spectrum 215-1 to sub-spectrum 215-m, and outputs the output spectrum 104 to the DA conversion unit 110. To do.

  For example, the spectrum combining unit 109a combines the sub-spectrums 215a-1 to 215a-m to generate the output spectrum 104a. The spectrum combining unit 109b combines the sub-spectrum 215b-1 to the sub-spectrum 215b-m to generate an output spectrum 104b.

  The DA conversion units 110a to 110n perform digital / analog conversion on the output spectrum converted into the continuous spectrum by the spectrum combining unit, and generate output spectra 104a to 104n. The spectrum combination unit 109 (109a to 109n) and the DA conversion unit 110 (110a to 110n) are an example of an output unit that generates and outputs the output spectrum 104 (104a to 104n).

  The repeater 500 according to the present embodiment is a repeater that enables digital processing including the AD conversion unit 105, the spectrum division unit 106, the exchange unit 107, the spectrum combination unit 109, and the AD conversion unit 110 as described above. Assumption.

  FIG. 4 is an example showing a functional configuration of switching section 107 that enables multiplexing in units of subspectrums, which is a feature of the present embodiment.

The exchanging unit 107 has a function of exchanging and multiplexing the sub-spectrum 214 divided by the spectrum dividing unit 106 in units of sub-spectrums.
The exchange unit 107 is an exchange that receives the sub-spectrums 214a-1 to 214n-m from the spectrum dividing units 106a to 106n and outputs the sub-spectrums 215a-1 to 215n-m to the spectrum combining units 109a to 109n.
For example, the sub spectrums 214a-1 to 214a-m from the spectrum dividing unit 106a are input to the input ports 220a-1 to 220a-m, and the sub spectra 214b-1 to 214b-m from the spectrum dividing unit 106b are input. Input to ports 220b-1 to 220b-m.

  The sub-spectrums 215a-1 to 215a-m output from the output ports 221a-1 to 221a-m are input to the spectrum combining unit 109a and output from the output ports 221b-1 to 221b-m. ˜215b-m are input to the spectrum combining unit 109b.

  The switching unit 107 includes a switch unit 230 and a sub-spectrum multiplexing unit 231. The switch unit 230 forms a switch matrix including, for example, crossbar switches, and sub-spectral multiplexing units 231 (231a-1 to 231n-m). Are provided in units of output ports 221 (output ports 221a-1 to 221n-m).

  The sub-spectrum multiplexing unit 231a-1 receives all the sub-spectrums 214a-1 to 214n-m output from the spectrum dividing units 106a to 106n via the switch unit 230. The sub-spectrum multiplexing unit 231a-1 selects a sub-spectrum from the input sub-spectrums 214a-1 to 214n-m and generates a multiplexed sub-spectrum 215a-1 in order to select and multiplex the sub-spectrum. The subspectral multiplexing unit 231a-2 generates a multiplexed signal from the input subspectrums 214a-1 to 214n-m, and generates a subspectrum 215a-2.

FIG. 5 is a diagram illustrating a subspectral multiplexing function of the subspectral multiplexing unit 231 of the repeater 500 according to the present embodiment.
As illustrated in FIG. 5, the sub-spectral multiplexing unit 231a-1 includes a gain control unit 240a-1 and a sub-spectral addition unit 241a-1. The sub-spectrum multiplexing unit 231a-1 follows the instructions from the multiple access control unit 400, and assigns weight values 242-1 to 242 to the sub-spectrums 214a-1 to 214n-m input from the input ports 243a-1 to 243n-m. Perform weighted multiplication using -x. The subspectral addition unit 241a-1 adds the multiplication results output from the gain control unit 240a-1.

An arbitrary subspectrum can be extracted and multiplexed by the subspectral multiplexing function of the subspectral multiplexing unit 231. Therefore, one or more subspectrums can be multiplexed simultaneously with the change of the frequency position of the subspectrum. In other words, by enabling sub-spectral multiplexing at the satellite repeater, it is possible to construct the switching unit 107 with a frequency conversion function having multiple access.
The subspectral multiplexing unit 231a-1 is an example of a subspectral multiplexing unit that enables selection and multiplexing of subspectra by performing gain control and subspectral addition.

  As described above, repeater 500 according to the present embodiment has a function of performing multiplexing in units of sub-spectrums, thereby allowing a plurality of input signals (for example, input signals 201, 202, and 203) to be mapped to different frequencies. The satellite relay station has a multiple access function characterized by multiplexing on the same frequency or the same sub-spectrum.

  FIG. 6 is a functional block diagram for illustrating the effect of implementation of repeater 500 according to the present embodiment, where signal 1 (250) and signal 2 (251) as input signals are multiplexed on the same subspectrum. An example is shown.

  FIG. 7 is a functional block diagram showing the effect of the implementation of the subspectral multiplexing unit 231 in the embodiment of FIG. 6 and 7, in repeater 500 according to the present embodiment, signals (signal 1 (250), signal 2 (251)) mapped to different frequency bands of different input spectra are the same sub The multiplexing function multiplexed in the spectrum will be described.

  FIG. 7 shows the subspectral multiplexing unit 231a-1. The subspectrums 214a-1 to 214a-m are input to the input ports 243a-1 to 243a-m, and the subspectrums 214b-1 to 214b-m are input to the input ports 243b-1 to 243b-m. . The multiple access control unit 400 multiplexes the sub-spectrums 214a-2 and 214b-m and outputs them from the output port 221a-1, so the weight 242-2 (W2) and the weight 242-x (Wx) are set to 1, and the others Is set to 0. Gain control section 240a-1 multiplies input subspectrums 214a-1 to 214b-m by weights using the weighting values specified by multiple access control section 400, and subspectral addition section 241a-1 performs multiplication. Add the results. Thereby, the signal 1 (250) and the signal 2 (251) are multiplexed on the same subspectrum 215a-1.

  As described above, repeater 500 according to the present embodiment is a satellite relay station having a digital signal processing function, and allows multiple communication signals received by satellites to be multiplexed without being reproduced. Has a connection function.

  Since repeater 500 according to the present embodiment has the multiple access function described above, it is possible to multiplex subchannels mapped to arbitrary frequencies of a plurality of input spectrums 113, and frequency utilization efficiency. To achieve frequency division multiple access.

Embodiment 2. FIG.
In this embodiment, code division multiplexing (CDMA: Code Division Multiplex) that multiplexes the spectrums of spread signals included in different input spectra 103a and 103b into the same frequency band for repeater 500 described in Embodiment 1. A method for performing (Access) will be described.

  As shown in FIG. 8, the input spectrum band (input spectrum 103a) includes a spread signal 1 (S1) spectrum 303 communicated in a predetermined frequency band (channel # 1) by the code division multiple method, and the input spectrum band ( The input spectrum 103b) includes a spread signal 2 (S2) spectrum 304 communicated in a predetermined frequency band (channel # 2) by a code division multiple method.

  If repeater 500 does not have a function for multiplexing signals (multiple access function), spread signal 1 (S1) spectrum 303 and spread signal 2 (S2) spectrum 304 must be mapped to different frequency bands. I must. However, since repeater 500 according to the present embodiment has a function of multiplexing signals (multiple access function), it multiplexes spread signal 1 (S1) spectrum 303 and spread signal 2 (S2) spectrum 304. Frequency utilization efficiency can be improved.

FIG. 8 is a diagram illustrating the effect of implementation of repeater 500 according to the present embodiment.
As shown in FIG. 8, the spectrum dividing unit 106a divides the input spectrum 103a into a plurality of sub-spectra 305a to 305d with a frequency bandwidth that is a unit of division. Also, the spectrum dividing unit 106b divides the input spectrum 103b into a plurality of sub-spectra 306a to 306d with a frequency bandwidth that is a unit of division. FIG. 8 shows an example in which the spectrum dividing units 106a and 106b perform spectrum division into four sub-spectrums for easy explanation.

  The exchange unit 107 includes a switch unit 230 and sub-spectral multiplexing units 231a-1 to 231a-4. The subspectral multiplexing unit 231 includes a gain control unit 240 (240a-1 to 240a-4) and a subspectral addition unit 241 (241a-1 to 241a-4).

  The subspectra 305a to 305d and 306a to 306d input to the switching unit 107 pass through the switch unit 230, and all the input subspectrums 305a to 305d and 306a to 306d are assigned to the subspectral multiplexing units 231a-1 to 231a-4. Input to each.

  The multiple access control unit 400 selects a sub-spectrum to be multiplexed by instructing the weighting values of the sub-spectral multiplexing units 231a-1 to 232a-4. In FIG. 8, the sub-spectrum 305a and the sub-spectrum 306a, the sub-spectrum 305b and the sub-spectrum 306b, the sub-spectrum 305c and the sub-spectrum 306c, the sub-spectrum 305d and the sub-spectrum 306d have a weight value of 1, and are multiplexed.

  That is, subspectrum 305a and subspectra 306a are multiplexed to generate subspectrum 307a, subspectra 305b and 306b are multiplexed to generate subspectrum 307b, subspectra 305c and 306c are multiplexed, and subspectrum 307c is generated. The spectra 305d and 306d are multiplexed to generate a subspectrum 307d.

  Then, the sub-spectrum 307a, the sub-spectrum 307b, the sub-spectrum 307c, and the sub-spectrum 307d are combined and output to the continuous output spectrum 104a in the spectrum combining unit 109a.

  As described above, repeater 500 according to the present embodiment is a satellite relay station having a digital signal processing function, and allows multiple communication signals received by satellites to be multiplexed without being reproduced. Has a connection function.

  Since repeater 500 according to the present embodiment has the above-described multiple access function, code division multiple access (CDMA: Code Division) is applied to communication signals included in different input spectra 103a and 103b. (Multiple Access) can be realized and the frequency utilization efficiency is improved.

Embodiment 3 FIG.
In this embodiment, a method of reducing the amount of noise added after code demultiplexing and frequency demultiplexing by performing gain control for each subspectrum (subchannel) in repeater 501 will be described.

  FIG. 9 is a functional block diagram of repeater 501 according to the present embodiment. FIG. 9 is a diagram corresponding to FIG. 1 described in the first embodiment, and functions similar to those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 9, the repeater 501 according to the present embodiment has a function of controlling the gain (signal power) of signals to be multiplexed by the multiple access control unit 400 determining the weight according to the gain control amount 401. Prepare.

  FIG. 10 shows an example of a multiplexing system characterized by performing gain control in order to reduce the amount of noise added after code demultiplexing and frequency demultiplexing. The functional blocks in FIG. 10 correspond to FIG. 8 of the second embodiment, and the same functions are denoted by the same reference numerals and the description thereof is omitted. In FIG. 10, the repeater 501 includes a gain control amount 401.

  The multiple access control unit 400 in FIG. 10 determines the gain control amount according to the gain control amount 401. FIG. 10 shows an input spread signal 1 with low S / N (SNR) (Signal to Noise Ratio) (spread signal 1 (S1) spectrum 303) and an input spread signal 2 with high S / N (SNR) (spread). An example in which the signal 2 (S2) spectrum 304) is code-demultiplexed (CDMA multiplexed) is shown. When code demultiplexing is performed at a satellite relay station, noise generated in the satellite reception system is added to each other. When the spread signal 1 (S1) spectrum 303 and the spread signal 2 (S2) spectrum 304 are multiplexed, the N1 noise 301 and the N2 noise 302 are also superimposed simultaneously.

  As shown in FIG. 10, the sub-spectrums 305 a to 305 d include noise (N1 noise 301) in the band in addition to the spectrum division signal component of the spread signal 1 (S 1) spectrum 303 that is an input signal. Similarly, the sub-spectrums 306a to 306d include noise in the band (N2 noise 302) in addition to the spectrum division signal component of the spread signal 2 (S2) spectrum 304 that is the input signal. In FIG. 10, the number of sub-spectrums is four, but the number of sub-spectrums is determined by the scale of the digital filter and is not limited to four.

  In order to alleviate the SNR degradation due to this noise power, the amount of noise power to be added can be reduced by lowering the gain of the channel having a margin in the SNR of the input spectrum. When there is a margin in the SNR of the input spectrum, it means that the signal power is sufficiently high with respect to the noise, and when there is no margin in the SNR of the input spectrum, it means that the margin of the signal power with respect to the noise is small. . FIG. 10 shows an example in which the SNR of spread signal 2 (S2) spectrum 304 is 3 dB larger than spread signal 1 (S1) spectrum 303 having the same desired SNR.

  In accordance with gain control amount 401, multiple access control section 400 multiplexes signal power to ½ by setting weight W = ½ for sub-spectra 306a to 306d of spread signal 2 (S2) spectrum 304. I do.

  In FIG. 10, the sub-spectrum 305a (weight W = 1) and the sub-spectrum 306a (weight W = 1/2) are multiplexed to generate a sub-spectrum 307a. The sub-spectrum 305b (weight W = 1) and the sub-spectrum 306b (weight) W = 1/2) is multiplexed to generate a subspectrum 307b, subspectrum 305c (weight W = 1) and subspectrum 306c (weight W = 1/2) are multiplexed to generate subspectrum 307c, and subspectrum 305d (Weight W = 1) and subspectrum 306d (weight W = 1/2) are multiplexed to generate subspectrum 307d.

  The sub-spectrum added by the spectrum adding units 241a-1 to 241a-4 is combined with the continuous spectrum by the spectrum combining unit 109a to generate the output spectrum 104a. The noise power of the noise 311 in the output spectrum 104a is N1 + N2 / 2, and the SNR of the output signal is improved to S1 / (N1 + N2 / 2) and (S2 / 2) / (N1 + N2 / 2). For example, when the noise powers (N1) and (N2) are equal, the SNR degradation amount is improved from 3 dB to 1.72 dB.

  As described above, according to the multiple access method using repeater 501 and repeater 501 according to the present embodiment, gain (weight) is controlled by multiple access control section 400 according to gain control amount 401, and subspectral multiplexing section. The amount of noise added to the same frequency band can be reduced by controlling the gain by the gain control unit 240 of 231 and the spread spectrum signal (spread signal 1 (S1) spectrum 303 mapped to the same frequency band can be reduced. And the SNR of the spread signal 2 (S2) spectrum 304) can be improved.

  Further, by implementing in combination with the first embodiment described above, it is possible to reduce the amount of noise added when multiplexing user channels even in frequency division multiple access.

Embodiment 4 FIG.
In the present embodiment, in the multiple access scheme (multiple access function) of the repeater 502 and the repeater 502 according to the present embodiment, the band of the spread spectrum signal is reduced (for example, 1 / N, N = 1, 2, 3, ...), a method of performing frequency multiplexing for mapping to different continuous frequencies will be described.

  For example, when the frequency band S (Hz) of the spread spectrum signal is reduced to 1 / N, the SNR deteriorates when S (Hz) is combined at the ground terminal. However, if the signal power of the spread spectrum signal is sufficiently higher than the noise, a method of reducing the frequency band to 1 / N can be used as a multiple access method (multiple access function).

  FIG. 11 is a functional block diagram of repeater 502 according to the present embodiment. FIG. 11 is a diagram corresponding to FIG. 1 described in the first embodiment, and functions similar to those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 11, repeater 502 according to the present embodiment determines the band of the multiplexed signal by determining the weight by multiple access control section 400 according to bandwidth control amount 402 in addition to gain control amount 401. It has a function to control.

  FIG. 12 is a functional block for explaining the effect of the repeater 502 and the multiple access method of the repeater 502 according to the present embodiment. As in Embodiment 3, spread signal 1 (S1) spectrum 303 and spread signal 2 (S2) spectrum 304 are input. The spectrum dividing units 106a and 106b divide the input spectrum into sub-spectra 305a to 305d and sub-spectra 306a to 306d.

  As shown in FIG. 12, the sub-spectrums 305a to 305d include noise (N1 noise 301) in the band in addition to the spectrum division signal component of the spread signal 1 (S1) spectrum 303 which is an input signal. Similarly, the sub-spectrums 306a to 306d include noise in the band (N2 noise 302) in addition to the spectrum division signal component of the spread signal 2 (S2) spectrum 304 that is the input signal. In order to reduce the SNR degradation due to the noise power, the bandwidth of the spread spectrum signal to be multiplexed is controlled. In FIG. 12, the number of sub-spectrums is four, but the number of sub-spectrums is determined by the scale of the digital filter and is not limited to four.

  In FIG. 12, the multiple access control unit 400 halves the bands of the spread signal 1 (S1) spectrum 303 and the spread signal 2 (S2) spectrum 304 in accordance with a predetermined band control amount 402. The weights 240a-1 to 240a-4 are determined.

  In FIG. 12, sub-spectrum 305a (weight W = 1) is selected and multiplexed to generate sub-spectrum 308a, sub-spectrum 305b (weight W = 1) is selected and multiplexed to generate sub-spectrum 308b, and sub-spectrum 306c ( A weight W = 1) is selected and multiplexed to generate a subspectrum 308c, and a subspectrum 306d (weight W = 1) is selected and multiplexed to generate a subspectrum 308d.

  In the multiple access control of the repeater 502 according to the present embodiment, different signals are not added at the same frequency, so the noise of the subspectra 308c to 308d is not added to the subspectra 308a to 308b. In addition, the noise of the subspectra 308a to 308b is not added to the subspectra 308c to 308d. Therefore, in the example of FIG. 12, since the band is halved, the SNR between the S1 output spread signal spectrum 291 and the S2 output spread signal spectrum 292 enables multiple access with 3 dB degradation.

  As described above, according to the multiple access method of repeater 502 and repeater 502 according to the present embodiment, a plurality of spread spectrum signals are reduced to the input spread spectrum signal band, and the band is reduced on the frequency axis. By mapping, a plurality of spread spectrum signals can be mapped within the input spread spectrum signal band, and the frequency utilization efficiency is improved.

Embodiment 5 FIG.
In the present embodiment, in the repeater 502 and the multiple access method (multiple access function) of the repeater 502 according to the present embodiment, the band of the spread spectrum signal is reduced according to the communication quality (for example, SNR) of the spread spectrum signal. (For example, 1 / N, N = 1, 2, 3,...), A frequency multiplexing method for mapping to different continuous frequencies will be described.

  FIG. 13 is a functional block diagram for explaining the effect of the repeater 502 and the multiple access method of the repeater 502 according to the present embodiment. As in Embodiment 3, spread signal 1 (S1) spectrum 303 and spread signal 2 (S2) spectrum 304 are input.

  The spectrum dividing units 106a and 106b divide the input spectrum 103a into sub-spectra 305a to 305d, and divide the input spectrum 103b into sub-spectra 306a to 306d. The multiple access control unit 400 increases the band reduction amount of the spread signal 1 (S1) spectrum 303 with a large SNR margin in accordance with a predetermined band control amount 402, and spread signal 2 (S2) spectrum 304 with a small SNR margin. The weights are determined so as to reduce the amount of band division, and the gain control function units 231a-1 to 231a-4 are instructed.

  The gain control function units 231a-1 to 231a-4 set the weight of the 3/4 band of the spread signal 1 (S1) spectrum 303 to 1 and the weight of the remaining 1/4 band to 0. Further, the weight of the 3/4 band of the S2 spread signal is set to 0, and the weight of the remaining 1/4 band is set to 1. Thereby, the sub-spectrums 309a to 309d are generated.

  In FIG. 13, sub-spectrum 305a (weight W = 1) is selected and multiplexed to generate sub-spectrum 309a, sub-spectrum 305b (weight W = 1) is selected and multiplexed to generate sub-spectrum 309b, and sub-spectrum 305c ( A weight W = 1) is selected and multiplexed to generate a subspectrum 309c, and a subspectrum 306d (weight W = 1) is selected and multiplexed to generate a subspectrum 309d.

  The output spectrum 104a combined with the continuous spectrum by the spectrum combining unit 109a includes the spread signal 1 (S1) spectrum 303 and the spread signal 2 (S2) spectrum 304, and the spread signal 1 (S1) spectrum 303 has a signal band. Is ¾ dB, and the degradation is -1.25 dB, and the spread signal 2 (S2) spectrum 304 is multiplexed with -6 dB degradation because the signal band is ¼.

  As described above, according to the multiple access method of repeater 502 and repeater 502 according to the present embodiment, a plurality of spread spectrum signals are converted into signal communication quality (for example, according to SNR) in the input spread spectrum signal band. By dividing the band and mapping on the frequency axis, the wireless communication quality is improved and the frequency utilization efficiency is improved.

Embodiment 6 FIG.
In this embodiment, a relay system 800 including the repeater 502, the ground terminal 700, and the control station 710 described in the fifth embodiment will be described. Relay system 800 according to the present embodiment changes gain control amount 401 and band control amount 402 according to communication quality evaluation (for example, BER: Bit / Error / Rate) observed by ground terminal 700.

  FIG. 14 is a functional block diagram of relay system 800 according to the present embodiment. The repeater 502 (satellite relay station) in FIG. 14 is the same as that described in FIG. The ground terminal 700 includes a demodulation unit 701 and a BER evaluation unit 702. In addition, the control station 710 includes a multiple access unit 711.

  The ground terminal 700 receives the downlink signal (output signal) output from the repeater 502. The demodulator 701 demodulates the input downlink signal by the processing device. The BER evaluation unit 702 performs BER evaluation by the BER evaluation method on the demodulated signal (demodulated signal) by the processing device. The BER evaluation unit 702 transmits evaluation result information indicating that the BER is not satisfied to the control station 710 when the BER value, which is the evaluation result, does not achieve the predetermined value. In the ground terminal 700, a threshold value of a BER value (BER value desired as a system) as an evaluation result is stored in advance in a storage device. Here, the evaluation method is not limited to the BER evaluation method, and may be another evaluation method.

  The multiple access unit 711 of the control station 710 changes the gain control amount 401 and the bandwidth control amount 402 for multiple access. The multiple access unit 711 receives the evaluation result information output from the ground terminal 700, calculates the gain control amount 401 and the band control amount 402 by the processing device based on the input evaluation result information, and calculates the calculated gain control. The amount 401 and the bandwidth control amount 402 are transmitted to the repeater 502. The multiple access unit 711 of the control station 710 is an example of a control amount calculation unit.

  For example, when the multiple access unit 711 receives evaluation result information indicating that the band of the spread signal 2 (S2) spectrum 304 is divided into ¼ but does not satisfy the desired BER (BER value threshold), “ The gain control amount 401 and the band control amount 402 for setting the band of the spread signal 2 (S2) spectrum 304 to 1/3 and the band of the spread signal 1 (S1) spectrum 303 to 2/3 "are the repeaters 502 ( To the multiple access control unit 400 of the satellite relay station.

  When the multiple access control unit 400 of the repeater 502 receives the gain control amount 401 and the bandwidth control amount 402 from the multiple access unit 711 of the control station 710, based on the input gain control amount 401 and bandwidth control amount 402, The gain control amount 401 and the band control amount 402 stored in the storage device are updated. Then, the multiple access control unit 400 performs gain control based on the updated gain control amount 401 and band control amount 402, and multiple processing for dividing and mapping the frequency band. The multiple processing by the multiple connection control unit 400 and the exchange unit 107 is as described in the first to fifth embodiments.

  As described above, according to relay system 800 according to the present embodiment, when a desired BER value is not achieved in gain control amount 401 and bandwidth control amount 402 that have been verified and determined in advance, communication performance of ground terminal 700 is achieved. By making the gain control amount 401 and the band control amount 402 variable according to the evaluation (for example, BER evaluation), it is possible to realize a multiple access function that can adapt to propagation environment changes (for example, weather changes).

  While the first to sixth embodiments have been described above, these six embodiments may be combined. Alternatively, one of these embodiments may be partially implemented. Alternatively, some of these six embodiments may be partially combined. Alternatively, these six embodiments may be combined in any way.

  In addition, although the above-described repeaters 500, 501, and 502 have been described as being mounted on a communication satellite, for example, the repeaters 500, 501, and 502 may be mounted on a ground communication station or the like.

  As described above, repeaters 500, 501, and 502 according to Embodiments 1 to 6 perform analog-to-digital conversion of an input spectrum using ADC, divide the spectrum into sub-spectrums using a spectrum dividing function, and perform exchange in units of sub-spectrums. A repeater (for example, a satellite repeater) that maps a sub-spectrum to an arbitrary frequency, converts the sub-spectrum into a continuous spectrum with a spectrum combining function, and performs digital-to-analog conversion with a DAC, and has a spectrum addition function A multiple access system function that enables frequency division multiplexing (FDMA: Frequency, Division, Multiple, Access) and code division multiplexing (CDMA: Code, Division, Multiple, Access) of multiple signals mapped to different frequencies. Have

  Also, repeaters 500, 501, and 502 according to Embodiments 1 to 6 reduce the amount of noise added after code demultiplexing and frequency demultiplexing by performing gain control for each subchannel (subspectrum). It has a multiple access system function.

  Also, repeaters 500, 501, and 502 according to Embodiments 1 to 6 convert the input spectrum from analog to digital by ADC, divide it into sub-spectrums by the spectrum dividing function, and perform sub-spectrum exchanges to perform sub-spectrums. Is mapped to an arbitrary frequency, the sub-spectrum is converted to a continuous spectrum by the spectrum combining function (returned), and the digital-analog conversion is performed by the DAC (in the satellite repeater, the band of the spread spectrum signal is divided, and the signal bandwidth It has a multiple access system function in a satellite relay station that realizes frequency sharing by frequency-multiplexing spread signals without increasing the frequency.

  In addition, repeaters 500, 501, and 502 according to Embodiments 1 to 6 have a multiple access scheme function that makes the division amount of the spread spectrum signal variable according to the communication evaluation at the ground terminal.

  103 input spectrum, 104 output spectrum, 105 AD conversion unit, 106 spectrum division unit, 107 exchange unit, 109 spectrum combination unit, 110 DA conversion unit, 214, 215 subspectrum, 220 input port, 221 output port, 230 switch unit, 231 sub-spectrum multiplexing unit, 240 gain control unit, 241 sub-spectrum addition unit, 242 weight value, 243 input port, 301 N1 noise, 302 N2 noise, 303 spread signal 1 (S1) spectrum, 304 spread signal 2 (S2) spectrum 305, 306, 307, 308, 309 sub-spectrum, 311 noise, 400 multiple access control unit, 401 gain control amount, 402 bandwidth control amount, 500, 501, 502 repeater, 700 ground terminal, 701 demodulation unit, 702 B ER evaluation section, 710 control station, 711 multiple access section, 800 relay system.

Claims (7)

An input section for inputting an input spectrum;
A spectrum dividing unit that divides the input spectrum input by the input unit into a plurality of sub-spectra;
An exchange unit comprising a plurality of output ports and a plurality of subspectral multiplexing units corresponding to the plurality of output ports, wherein each subspectral multiplexing unit inputs the plurality of subspectra divided by the spectrum dividing unit. Multiplex at least a part of sub-spectrums of the plurality of input sub-spectrums to generate one multi-sub-spectrum, and output the generated multi-sub-spectra to a corresponding output port of the plurality of output ports. An exchange,
A repeater comprising: a spectrum combiner configured to combine a plurality of the multiple sub-spectrums output from the plurality of output ports to generate an output spectrum. The exchange unit is
A switch unit that inputs the plurality of sub-spectrums and outputs to each sub-spectrum multiplexing unit of the plurality of sub-spectral multiplexing units;
Each sub-spectrum multiplexing unit of the plurality of sub-spectral multiplexing units is
The multiple sub-spectrum is input by inputting the plurality of sub-spectrums from the switch unit, selecting the at least some sub-spectrums from the plurality of input sub-spectrums, and adding the selected at least some sub-spectra. The repeater according to claim 1, wherein: The exchange unit further includes:
A multiple access control unit for designating a weight value for weighting each subspectrum of the plurality of subspectra;
Each sub-spectrum multiplexing unit of the plurality of sub-spectral multiplexing units is
A gain control unit that selects the at least some sub-spectrums by multiplying each of the plurality of sub-spectrums by the weight value specified by the multiple access control unit;
A sub-spectrum addition unit that generates the multiple sub-spectrum by adding at least a part of the sub-spectrums selected by the gain control unit, and outputs the generated multiple sub-spectrum to the corresponding output port. The repeater according to claim 2. The exchange unit further includes:
A multiple access control unit for selecting and specifying a part of the plurality of sub-spectrums including a plurality of communication signals;
Each sub-spectrum multiplexing unit of the plurality of sub-spectral multiplexing units is
Of the plurality of communication signals, the sub-spectrum including one communication signal and the sub-spectrum including the communication signal different from the one communication signal do not overlap the bands of the one communication signal and the different communication signal. 3. The repeater according to claim 2, further comprising: a sub-spectrum adding unit configured to generate the multiple sub-spectrum by multiplexing and to output the generated multiple sub-spectrum to the corresponding output port. The input spectrum includes a communication signal and a noise signal,
The multiple access control unit
A signal quality value indicating a ratio between the communication signal and the noise signal included in the input spectrum is calculated, and gains of the plurality of sub-spectrums corresponding to the input spectrum are controlled based on the calculated signal quality value 4. The repeater according to claim 3, wherein a gain control amount to be determined is determined, and the weight value is designated based on the determined gain control amount. The input spectrum includes a communication signal and a noise signal,
The multiple access control unit
A signal quality value indicating a ratio between the communication signal and the noise signal included in the input spectrum is calculated, and based on the calculated signal quality value, the plurality of sub-spectrums corresponding to the input spectrum are the output spectrum. 4. The repeater according to claim 3, wherein a bandwidth control amount that is an amount occupying a frequency band is determined, and the sub-spectrum is selected and instructed based on the determined bandwidth control amount. In a relay system comprising a repeater that relays an input spectrum, a terminal that receives an output spectrum output from the repeater, and a control station,
The repeater is
A spectrum dividing unit for dividing the input spectrum into a plurality of sub-spectra;
An exchange unit comprising a plurality of output ports and a plurality of sub-spectrum multiplexing units corresponding to the plurality of output ports, each sub-spectrum multiplexing unit receiving the plurality of sub-spectrums and inputting the plurality of sub-spectrums An exchange unit that multiplexes at least some of the sub-spectra to generate one multi-sub-spectrum and outputs the generated multi-sub-spectrum to a corresponding output port;
A plurality of the multiple sub-spectra output from the plurality of output ports are combined to generate the output spectrum;
The exchange unit is
Based on a control amount stored in a storage device, a multiple access control unit that selects and indicates at least a part of the plurality of sub-spectrums,
Each sub-spectrum multiplexing unit of the plurality of sub-spectral multiplexing units is
Input the plurality of sub-spectrums, select the at least some sub-spectrums instructed by the multiple access control unit from each sub-spectrum of the plurality of input sub-spectrums, and select the at least some sub-spectrums Generating the multiple sub-spectrum by adding the spectrum, outputting the generated multiple sub-spectrum to the corresponding output port;
The terminal
A demodulator that inputs the output spectrum output from the repeater, demodulates the input output spectrum, and generates a demodulated signal;
A quality evaluation unit that evaluates the quality of the demodulated signal generated by the demodulation unit by a predetermined evaluation method and outputs a quality evaluation result;
The control station
A control amount calculation unit that inputs the quality evaluation result output by the terminal, calculates a control amount based on the input quality evaluation result, and transmits the calculated control amount to the multiple access control unit of the repeater With
The multiple access control unit
A relay system that receives the control amount calculated by the control amount calculation unit and updates the control amount stored in a storage device to the control amount calculated by the control amount calculation unit.

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