JP2004356665A - Satellite communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a satellite communication system capable of rapidly improving utilization efficiency of a line by optimizing an encoding rate with high followability to changes in a communication environment. <P>SOLUTION: A reception signal level detecting circuit 121 detects the power level of a received signal. A UW pattern detecting circuit 125 detects a UW pattern from the received data, and determines an encoding rate desired by an opposite communication party from this. An error correction control circuit 127 measures the occurrence frequency of error correction of the received data, and decides the optimum encoding rate on the basis of this occurrence frequency and the detected level of the circuit 121. A control processor 100 generates encoding rate information on the basis of a result of determination of the circuit 125 and the encoding rate decided by the circuit 127, and provides this information to a convolutional encoding circuit 101 and a UW pattern adding circuit 102 to perform exchange with the communication opposite station to perform variable control of an encoding rate to be used for transmission/reception. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a satellite communication system that varies a transmission rate according to an amount of information to be transmitted.
[0002]
[Prior art]
As is well known, a conventional satellite communication system employs a modulation / demodulation device having a multi-rate transmission function, and considers C / N degradation (carrier attenuation of up to about 10 dB) due to rain attenuation in line design. In general, an error correction function is provided. For example, it is a convolutional code (coding rate 1/2). In this case, the data transmission efficiency per band is 0.5 when the error correction is not performed, and is 0.5 with respect to C / N, but is halved as the transmission efficiency.
[0003]
A major cause of C / N degradation in satellite communication systems is rain attenuation. A small amount of rain causes a deterioration of about several dB, and a heavy rain causes a deterioration of about 10 dB at the maximum. Considered throughout the year, the C / N hardly deteriorates by about 10 dB, and the C / N is stable for many hours, and the line quality is sufficiently stable even without the error correction function. Can be secured.
[0004]
Further, in a conventional satellite communication system, voice / fax data of 32 kbps, image data of about 64 k to 6312 kbps, etc. have been mainly used as information data. Also, the transmission bandwidth was determined for each information data rate. Therefore, when performing error correction coding on the information data signal, the coding rate (for example, convolutional coding coding rate: 1/2) is also constant, and need not be made variable.
[0005]
In recent satellite communication systems, systems mainly using IP data transmission are increasing. In this case, the communication information speed between the stations is variable according to the amount of transmission information. For example, when the amount of information is large, the transmission band is widened and the modulation speed is set to a maximum of about 6 MBaud. If the amount of information is small, the transmission band is narrowed, and the modulation rate is reduced to a minimum of about 35 kBaud.
[0006]
However, in a satellite communication system, the band allocated to the whole is limited to about 500 MHz at the maximum, and merely expanding the transmission band with respect to the information amount increases the number of stations that want to communicate a large amount of information. The band to be used is restricted, and if the band can be restricted, the information transmission time will be correspondingly increased.
[0007]
Therefore, conventionally, a communication system that switches the encoding / decoding method when the line quality is deteriorated and compensates for the deterioration of the line quality has been considered (for example, see Patent Document 1).
However, in the conventional method, since the encoding / decoding method is switched after the line quality is deteriorated, there is a problem that the ability to follow a change in the communication environment is extremely low.
[0008]
[Patent Document 1]
JP-A-2000-123456 (page 5-7, FIG. 1).
[0009]
[Problems to be solved by the invention]
In the conventional satellite communication system, since the encoding / decoding method is switched after the line quality is deteriorated, there is a problem that the ability to follow a change in the communication environment is extremely low.
SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a satellite communication apparatus capable of optimizing a coding rate with high followability to a change in a communication environment and quickly increasing line utilization efficiency. The purpose is to do.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, in a satellite communication device for communicating with an artificial satellite, a power level detecting means for detecting a power level of a received signal, and a detection result of the power level detecting means , And a transmission control unit that encodes and transmits transmission data at the coding rate determined by the determining unit.
[0011]
In the satellite communication device having the above configuration, the transmission data is encoded and transmitted at the encoding rate determined based on the power level of the received signal.
Therefore, according to the satellite communication apparatus having the above configuration, the coding rate can be varied before the communication environment deteriorates and an error occurs in the received signal by the coding rate control based on the power level of the received signal. It is possible to optimize the coding rate with high followability to the change, and to quickly increase the line use efficiency.
[0012]
Further, according to the present invention, in a satellite communication device for communicating with an artificial satellite, an error rate detecting means for detecting an occurrence rate of error correction for a received signal, and a power level detecting means for detecting a power level of the received signal. Determining means for determining a coding rate based on the detection result of the error rate detecting means and the detection result of the power level detecting means, and encoding and transmitting the transmission data at the coding rate determined by the determining means And a transmission control means.
[0013]
In the satellite communication apparatus having the above configuration, transmission data is encoded and transmitted at a coding rate determined based on the power level of the received signal and the rate of occurrence of error correction for the received signal.
Therefore, according to the satellite communication device having the above configuration, since the coding rate is determined in consideration of the power level of the received signal, compared to the case where the coding rate is changed based only on the occurrence rate of error correction, It is possible to optimize the coding rate with high followability to changes in the communication environment, and quickly increase the line utilization efficiency.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a configuration of a satellite communication device of an earth station used in a satellite communication system according to an embodiment of the present invention.
[0015]
The convolution encoding circuit 101 encodes each of the I and Q transmission data given from the control processing unit 100 at a coding rate based on the coding rate information from the control processing unit 100 described later. Here, the coding rate corresponds to one of three types, 1/2, 3/4, and 7/8. The obtained I and Q encoded data are both output to the UW pattern adding circuit 102.
[0016]
The UW pattern adding circuit 102 converts a UW pattern corresponding to each coding rate (1/2, 3/4, 7/8) based on the coding rate information from the control processing unit 100 into a convolutional coding circuit. Attached to the I and Q encoded data input from 101. The UW pattern added here is always at the coding rate “率”.
[0017]
In this way, the encoded data of I to which the UW pattern is added passes through the root Nyquist filter (RNF) 103a, and is then converted into an analog signal by the D / A converter (D / A) 104a, The signal is output to the converter 106a via the switch 105a.
Similarly, the coded data of Q to which the UW pattern is added passes through a root Nyquist filter (RNF) 103b, and is then converted into an analog signal by a D / A converter (D / A) 104b. Via the converter 106b.
[0018]
On the other hand, the oscillation signal generated by the oscillator 108 is converted by the phase shifter (-π / 4) 107a and the phase shifter (+ π / 4) 107b into quadrature signals having a phase difference of π / 2 from each other. . The converters 106a and 106b use the signals for quadrature modulation of the analog transmission signal via the root Nyquist filters 103a and 103b.
[0019]
The quadrature-modulated analog transmission signal passes through an attenuator (ATT) 109, is amplified by a power amplifier 110, and is band-limited by a band-pass filter 111. Thereafter, the signal is up-converted from a signal in the 1 GHz band to a signal in the 14/12 GHz band by an ODU (Out Door Unit) 112 and transmitted from the antenna 113 to the satellite.
[0020]
The signal received by the antenna 113 from the satellite is down-converted by the ODU 112 from a signal in the 14/12 GHz band to a signal in the 1 GHz band. Then, after being band-limited by the band-pass filter 114, the signal is amplified by the low noise amplifier 115 and output to the converters 116a and 116b.
[0021]
On the other hand, the oscillation signal generated by the oscillator 118 is converted into a quadrature signal having a phase difference of π / 2 from each other by the phase shifter (−π / 4) 117a and the phase shifter (+ π / 4) 117b. . The converters 116a and 116b use the received signal amplified by the low noise amplifier 115 for quadrature demodulation.
[0022]
The received signal demodulated by converter 116a passes through low-pass filter 119a, is amplified by amplifier 120a, and is output to received signal level detection circuit 121 and A / D converter (A / D) 122a. The received signal converted to a digital signal by the A / D converter 122a is output to a digital demodulation circuit 124 after passing through a root Nyquist filter (RNF) 123a.
[0023]
Similarly, the received signal demodulated by converter 116b passes through low-pass filter 119b, is then amplified by amplifier 120b, and output to received signal level detection circuit 121 and A / D converter (A / D) 122b. You. Then, the received signal converted into a digital signal by the A / D converter 122b is output to a digital demodulation circuit 124 after passing through a root Nyquist filter (RNF) 123b.
[0024]
Received signal level detection circuit 121 detects the power level of the received signal output from amplifier 120a and the power level of the received signal output from amplifier 120b, and outputs the detection result to error correction control circuit 127.
Digital demodulation circuit 124 digitally demodulates the outputs of root Nyquist filters 123a and 123b, and reproduces two received data. These two received data are output to the UW pattern detection circuit 125, the soft decision Viterbi decoding circuit 126, and the error correction control circuit 127.
[0025]
The UW pattern detection circuit 125 detects a UW pattern added to each of the two received data reproduced by the digital demodulation circuit 124, and detects a convolutional coding rate (1/1) indicated by the detected UW pattern. (2, 3/4, 7/8), and notifies the control processing unit 100 of this determination result.
[0026]
The soft-decision Viterbi decoding circuit 126 decodes the two received data reproduced by the digital demodulation circuit 124 at a coding rate according to the coding rate information notified from the control processing unit 100, and outputs each of I and Q. The received data is reproduced and output to the control processing unit 100.
[0027]
The error correction control circuit 127 measures the frequency of occurrence of error correction of the two pieces of received data reproduced by the digital demodulation circuit 124, and based on the measured occurrence frequency and the detection level of the received signal level detection circuit 121. The coding rate is determined, and this is notified to the control processing unit 100.
[0028]
Here, the convolutional coding rate control of the error correction control circuit 127 will be described with reference to FIG. FIG. 2 is a flowchart for explaining the control operation. The error correction control circuit 127 determines whether or not data communication is being performed in step 2a. Here, if data communication is being performed, the process proceeds to step 2b. If data communication is not being performed, the process proceeds to step 2f.
[0029]
In step 2b, the error correction control circuit 127 measures the frequency of occurrence of error correction of the two received data reproduced by the digital demodulation circuit 124, and proceeds to step 2c.
In step 2c, the error correction control circuit 127 determines whether the frequency of occurrence of error correction measured in step 2b is equal to or less than a preset first reference value. Here, if the frequency of occurrence of error correction measured in step 2b is equal to or less than the first reference value set in advance, the process proceeds to step 2d, and the frequency of occurrence is set to be smaller than the first reference value set in advance. If it is higher, the process proceeds to step 2f.
[0030]
In step 2d, the error correction control circuit 127 determines whether the detection level detected by the reception signal level detection circuit 121 is equal to or higher than a preset second reference value. Here, if the detection level detected by the reception signal level detection circuit 121 is equal to or higher than the second reference value set in advance, the process proceeds to step 2h, and the detection level is changed to the second reference value set in advance. If less than, the process proceeds to step 2e.
[0031]
In step 2e, the error correction control circuit 127 determines whether or not the detection level detected by the reception signal level detection circuit 121 is equal to or higher than a preset third reference value (<second reference value). Here, if the detection level detected by the reception signal level detection circuit 121 is equal to or higher than the third reference value set in advance, the process proceeds to step 2g, and the detection level is changed to the third reference value set in advance. If it is less, the process proceeds to step 2f.
[0032]
In step 2f, the error correction control circuit 127 determines that the convolutional coding rate should be set to "1/2" of the initial value, notifies this to the control processing unit 100, and proceeds to step 2a. On the other hand, the control processing unit 100 gives “1/2” as coding rate information to the convolutional coding circuit 101 and the UW pattern adding circuit 102 based on the notified determination result, An error correction request signal including a UW pattern corresponding to "1/2" is transmitted to a communication partner. Thereafter, when receiving the error correction request response signal for accepting the change of the coding rate from the communication partner, the control processing unit 100 transmits the error correction change signal to the communication partner at the timing indicated by the response signal, and controls each unit. Then, transmission and reception are performed at an encoding rate of “１ ／”. At this time, if the convolutional coding rate has already been set to "1/2", the process proceeds to step 2a without performing the process of step 2f.
[0033]
In step 2g, the error correction control circuit 127 determines that the convolutional coding rate should be “3/4”, notifies the control processing unit 100 of this, and shifts to step 2a. On the other hand, the control processing unit 100 gives “3/4” as coding rate information to the convolutional coding circuit 101 and the UW pattern adding circuit 102 based on the notified determination result, An error correction request signal including a UW pattern corresponding to “3/4” is transmitted to a communication partner. Thereafter, when receiving the error correction request response signal for accepting the change of the coding rate from the communication partner, the control processing unit 100 transmits the error correction change signal to the communication partner at the timing indicated by the response signal, and controls each unit. Then, transmission and reception are performed at the coding rate “3/4”. At this time, if the convolutional coding rate has already been set to "3/4", the process proceeds to step 2a without performing the process of step 2g.
[0034]
In step 2h, the error correction control circuit 127 determines that the convolutional coding rate should be “7/8”, notifies this to the control processing unit 100, and proceeds to step 2a. On the other hand, the control processing unit 100 gives “7/8” as coding rate information to the convolutional coding circuit 101 and the UW pattern adding circuit 102 based on the notified determination result, An error correction request signal including a UW pattern corresponding to “7/8” is transmitted to a communication partner. Thereafter, when receiving the error correction request response signal for accepting the change of the coding rate from the communication partner, the control processing unit 100 transmits the error correction change signal to the communication partner at the timing indicated by the response signal, and controls each unit. Then, transmission and reception are performed at the coding rate “7/8”. If the convolutional coding rate has already been set to "7/8" at this time, the process proceeds to step 2a without performing the process of step 2h.
[0035]
The control processing unit 100 controls the respective units of the satellite communication device in accordance with an instruction from a terminal device (not shown), and based on the determination results of the UW pattern detection circuit 125 and the error correction control circuit 127. To generate convolutional coding information and to provide the convolutional coding circuit 101 and a UW (unique word) pattern adding circuit 102 to exchange with a communication partner station and perform variable control of a coding rate used for transmission and reception.
[0036]
Next, an operation in the case where the earth stations A and B using the satellite communication device having the above configuration communicate via the satellite station ST will be described. FIG. 3 shows a sequence of the operation. The earth station A includes a terminal device 10A and a satellite communication device 100A, and the earth station B includes a terminal device 10B and a satellite communication device 100B. Here, particularly, an operation including a sequence for changing an error correction coding rate will be described.
[0037]
First, a sequence S1 for performing line assignment will be described.
In the earth station A, when the satellite communication device 100A receives the transmission request from the terminal device 10A, the satellite communication device 100A requests the satellite station ST to allocate a line. On the other hand, the satellite station ST detects an empty line and designates the empty line to the terminal devices 10A and 10B. On the other hand, the satellite communication device 100A transmits transmission information through the allocated free line, while the satellite communication device 100B transmits information for confirming the line through the allocated free line.
[0038]
When the satellite station ST receives the transmission information from the satellite communication device 100A through the allocated line, the satellite station ST transfers this to the satellite communication device 100B. On the other hand, the satellite communication device 100B transmits a response signal (transmission information response) to the transmission information and activates the terminal device 10B. When the terminal device 10B is activated and a response signal is given to the satellite communication device 100B, the satellite communication device 100B transmits the response signal to the satellite station ST.
[0039]
On the other hand, the satellite station ST transmits the transmission information response and the response signal received from the satellite communication device 100B to the satellite communication device 100A. On the other hand, the satellite communication device 100A transmits a response confirmation signal to the satellite station ST. On the other hand, the satellite station ST transmits the response confirmation signal received from the satellite communication device 100A to the satellite communication device 100B. As described above, a communication link is established between the earth station A and the earth station B via the satellite station ST, and data communication is started in the subsequent sequence S2.
[0040]
In the sequence S2, data communication is started with the coding rate being “「 ”, and the error correction control circuit 127 of the satellite communication device 100A sets the coding rate to“ 7 ”by the convolutional coding rate control shown in FIG. / 8 ". This determination result is notified to the control processing unit 100. On the other hand, the control processing unit 100 gives the notified determination result as coding rate information to the convolutional coding circuit 101 and the UW pattern adding circuit 102, and transmits the result to the earth station B as an error correction request.
[0041]
On the other hand, in the satellite communication device 100B, the UW pattern detection circuit 125 detects the UW patterns respectively added to the two received data reproduced by the digital demodulation circuit 124, and detects the detected UW pattern. , It detects that the satellite communication device 100A has made a request to set the convolutional coding rate to “7/8”, and notifies the control processing unit 100 of this. On the other hand, the control processing unit 100 causes the error correction control circuit 127 to determine whether the coding rate should be “7/8”. Then, when the error correction control circuit 127 determines that the coding rate “7/8” is appropriate, the control processing unit 100 causes a response signal of the error correction request to be transmitted.
[0042]
Thereafter, the satellite communication device 100A that has received the response signal from the satellite communication device 100B and the satellite communication device 100B that has transmitted the response signal mutually perform error correction coding at the timing indicated by the information in the response signal. When a signal for changing the rate is transmitted and the signal is received from the other, data transmission is started at a convolutional coding rate of "7/8" as a sequence S3.
[0043]
Eventually, as a sequence S4, when the satellite communication device 100A receives a disconnection request from the terminal device 10A to end the data communication, the satellite communication device 100A transmits a disconnection signal to the satellite station ST. This signal is transferred to satellite communication device 100B through satellite station ST.
[0044]
Upon receiving the disconnection signal, the satellite communication device 100B transmits a disconnection response signal to the satellite station ST, notifies the terminal device 10B of the disconnection, and disconnects the communication link with the terminal device 10B. Then, the satellite communication device 100A and the satellite communication device 100B request the satellite station ST for restoration, respectively, and the satellite station ST transmits a signal indicating the restoration confirmation to the satellite communication device 100A and the satellite communication device 100B. Satellite communication device 100A and satellite communication device 100B that have received this signal notify terminal device 10A and terminal device 10B of the end, respectively, and the communication ends.
[0045]
FIG. 4 shows signal frames transmitted from the satellite communication device 100A and the satellite communication device 100B in the above-described sequence on one time axis.
Of the transmission data shown in this figure, the error correction request signal Ca1, the error correction request response signal Cb1, and the error correction change signals Ca2 and Cb2, which are control signals for changing the convolutional coding rate of error correction, are always In order to ensure stable line quality, the coding rate is not changed and the coding rate is always "1/2" without being changed.
[0046]
As described above, in the satellite communication device 100A and the satellite communication device 100B having the above configurations, the occurrence rate of error correction and the power level of the received signal are detected at the earth station, and the error correction determined based on the detection results is performed. The coding rate is notified to the communication partner station, and the coding rate used for data communication is changed.
[0047]
Therefore, according to the satellite communication device 100A and the satellite communication device 100B having the above configuration, the coding rate is determined in consideration of the power level of the received signal, so that the coding rate is determined based only on the error correction occurrence rate. Compared with the case of changing, the coding rate can be optimized with high follow-up to the change of the communication environment, and the line use efficiency can be quickly increased.
[0048]
It should be noted that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying constituent elements in an implementation stage without departing from the scope of the invention. Various inventions can be formed by appropriately combining a plurality of components disclosed in the above embodiments. Further, for example, a configuration in which some components are deleted from all the components shown in the embodiment is also conceivable. Further, components described in different embodiments may be appropriately combined.
[0049]
For example, in the above embodiment, for example, the occurrence rate of error correction and the power level of the received signal are respectively detected, and the coding rate of error correction is changed based on these detection results. Alternatively, based on only the detection result of the power level of the received signal, a plurality of error correction coding rates may be selectively used by another-stage threshold determination.
[0050]
Further, in the above-described embodiment, the coding rate actually used is determined after confirming mutually suitable coding rates between the two earth stations A and B that perform communication. For example, the coding rate may be changed by the judgment of one of the earth stations, and the other party may be notified of the coding rate to be used.
[0051]
Further, in the above-described embodiment, the configuration has been described in which the two earth stations A and B communicate with each other at the same coding rate, but the present invention can also be applied to a system that communicates with different coding rates. Also, the present invention can be applied to a system using different coding rates between the earth station A and the satellite station ST and between the earth station B and the satellite station ST.
[0052]
In addition, it goes without saying that various modifications can be made without departing from the scope of the present invention.
[0053]
【The invention's effect】
As described above, according to the present invention, transmission data is encoded and transmitted at the encoding rate determined based on the power level of the received signal.
Therefore, according to the present invention, by controlling the coding rate based on the power level of the received signal, the coding rate can be changed before the communication environment deteriorates and an error occurs in the received signal. It is possible to provide a satellite communication device capable of optimizing a coding rate with high tracking performance and quickly increasing the use efficiency of a line.
[0054]
Further, according to the present invention, the transmission data is encoded and transmitted at a coding rate determined based on the power level of the received signal and the rate of occurrence of error correction for the received signal.
Therefore, according to the present invention, since the coding rate is determined in consideration of the power level of the received signal, the change in the communication environment can be reduced as compared with the case where the coding rate is changed based only on the error correction occurrence rate. To provide a satellite communication device capable of optimizing the coding rate with high tracking performance and quickly increasing the line utilization efficiency.
[Brief description of the drawings]
FIG. 1 is a circuit block diagram showing a configuration of a satellite communication device of an earth station used in a satellite communication system according to the present invention.
FIG. 2 is a flowchart for explaining the operation of the error correction control circuit of the satellite communication device shown in FIG.
FIG. 3 is a diagram showing an example of a communication sequence of the satellite communication system according to the present invention.
FIG. 4 is a diagram showing a frame configuration of signals transmitted by two earth stations according to the communication sequence shown in FIG. 4;
[Explanation of symbols]
100A: Satellite communication device, 100B: Satellite communication device, 10A: Terminal device, 10B: Terminal device, 100: Control processing unit, 101: Convolutional coding circuit, 102: Pattern addition circuit, 103a: Root Nyquist filter (RNF) 103b ... Root Nyquist filter (RNF), 104a ... D / A converter (D / A), 104b ... D / A converter (D / A), 105a ... Low pass filter, 105b ... Low pass filter, 106a ... Converter , 106b converter, 107a phase shifter (-π / 4), 107b phase shifter (+ π / 4), 108 oscillator, 109 attenuator (ATT), 110 power amplifier, 111 bandpass filter 112, ODU (Out Door Unit), 113, antenna, 114, band-pass filter, 115, Rhono Amplifier, 116a converter, 116b converter, 117a phase shifter (-π / 4), 117b phase shifter (+ π / 4), 118 oscillator, 119a low-pass filter, 119b low-pass filter, 120a ... Amplifier, 120b ... Amplifier, 121 ... Received signal level detection circuit, 122a ... A / D converter (A / D), 122b ... A / D converter (A / D), 123a ... Root Nyquist filter (RNF), 123b: root Nyquist filter (RNF), 124: digital demodulation circuit, 125: UW pattern detection circuit, 126: soft decision Viterbi decoding circuit, 127: error correction control circuit, A: earth station, B: earth station, ST: satellite Bureau.

Claims (5)

In a satellite communication device that communicates with an artificial satellite,
Power level detection means for detecting the power level of the received signal;
Determining means for determining a coding rate based on a detection result of the power level detecting means;
A satellite communication apparatus comprising: a transmission control unit that encodes transmission data at a coding rate determined by the determination unit and transmits the data. In a satellite communication device that communicates with an artificial satellite,
Error rate detection means for detecting the rate of occurrence of error correction for the received signal;
Power level detection means for detecting the power level of the received signal;
Determination means for determining a coding rate based on the detection result of the error rate detection means and the detection result of the power level detection means,
A satellite communication apparatus comprising: a transmission control unit that encodes transmission data at a coding rate determined by the determination unit and transmits the data. 2. The method according to claim 1, wherein the determining unit determines the coding rate according to the detection result of the power level detecting unit when the detection result of the error rate detecting unit is equal to or less than a preset threshold value. Item 3. A satellite communication device according to item 2. The method according to claim 1, wherein the determining unit determines the coding rate to be a higher value as the detection level of the power level detecting unit is higher, when a detection result of the error rate detecting unit is equal to or less than a preset threshold. The satellite communication device according to claim 1 or 2. Further, receiving means for receiving coding rate information indicating a coding rate from the communication partner,
The transmission control means determines a coding rate based on the coding rate indicated by the coding rate information received by the receiving means and the coding rate determined by the determining means, and determines the transmission data at the coding rate. 5. The satellite communication device according to claim 1, wherein the satellite communication device is encoded and transmitted.

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