A broadband signal real-time digital predistortion method, terminal and system

Abstract

The present invention discloses a broadband signal real-time digital predistortion method, terminal and system, belonging to the field of information transmission and processing. The present invention adopts framing, coding, shaping filtering, DA conversion, AD coding, matching filtering, clock recovery, carrier recovery, decoding, data extraction, time domain equalization and tap update processing at the ground end, and adopts framing, coding, shaping filtering, DA conversion, AD coding, matching filtering, clock recovery, carrier recovery, decoding and data extraction processing at the satellite end, which can match the distortion of the channel and realize compensation for the distortion of the channel. The satellite-borne platform of the present invention can save the digital equalizer with large resource occupation, and has a relatively obvious improvement on the weight, volume and power consumption of the satellite-borne platform, and can respond to the distortion of the channel in a short time.

Description

Technical Field

[0001] The present invention relates to the field of information transmission and processing, and in particular to a broadband signal real-time digital predistortion method, terminal and system, which can realize real-time digital predistortion of high-orbit and low-orbit feeder links. Background Art

[0002] The feeder link is a link that connects high-orbit communication satellites and ground gateway stations to transmit high-speed broadband information. The satellite-to-ground broadband information transmission link mainly involves broadband baseband signal generation devices, broadband up-conversion devices, broadband high-power amplifiers, antennas, broadband down-conversion devices, and broadband baseband signal processing devices. The transmission link is divided into an uplink and a downlink. The uplink is for ground equipment to send broadband signals, and the satellite payload receives and processes the broadband signals sent from the ground; the downlink is for the satellite payload to send broadband signals, and the ground equipment receives and processes the broadband signals sent from the satellite payload. When the transmitted signal passes through broadband converters, broadband high-power amplifiers, filters and other devices, due to the nonlinearity of the device itself, serious nonlinear distortion will be generated, which has a very bad effect on the transmission quality of the channel. In the case of severe channel distortion, the spectrum expansion is serious, the constellation diagram of the received signal is divergent and distorted, and linear and nonlinear inter-code interference is mixed, which seriously undermines the stability of the satellite communication system under high-speed data transmission.

[0003] At present, the downlink is generally achieved by adding a digital equalizer to the ground receiving equipment. After the transmission signal is equalized by the equalizer, the inter-code interference is significantly reduced, and the problems of spectrum expansion, constellation diagram divergence and distortion are also greatly improved. The digital equalizer commonly used in engineering uses filtering technology to achieve equalization. According to the equalization algorithm set inside the equalizer, the tap coefficient of the filter inside the equalizer is changed through iterative calculation, so that the tap vector of the equalizer matches the channel transmission parameter, thereby achieving compensation for channel distortion. However, the equalizer will occupy a large amount of multiplier resources, especially for broadband link signals, which require 8 or even 16 parallel equalizers, and the resource occupation is as much as 1 / 3 or even 1 / 2 of the ground receiving processing resources. For ground receiving equipment with unlimited weight, volume and power consumption, only additional processing chips are needed to complete the equalizer function, but for satellite receiving equipment with limited weight, volume and power consumption, it is not acceptable. Therefore, the equalizer function of the uplink needs to be transferred to the ground equipment for implementation. Summary of the invention

[0004] In view of this, the present invention provides a broadband signal real-time digital predistortion method, terminal and system. The present invention does not require the satellite-borne receiving and processing equipment to implement the equalizer function, but when the ground equipment sends the signal, the transmission signal is predistorted in advance according to the distortion of the channel, so as to match the distortion of the channel and realize compensation for the channel distortion.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A broadband signal real-time digital predistortion method comprises the following steps:

[0007] Step 1: The framing unit of the ground broadband signal processing terminal performs a framing operation on the received service data. When there is service data, the framing unit outputs a service frame, and when there is no service data, the framing unit outputs an empty frame, thereby ensuring that the output data stream is continuous;

[0008] Step 2, the encoding unit of the ground broadband signal processing terminal performs channel encoding on the data stream output by the framing unit;

[0009] Step 3: The shaping filter unit of the ground broadband signal processing terminal performs shaping filter processing on the encoded data. The tap coefficients of the shaping filter initially use default values, and no pre-distortion is performed on the output signal.

[0010] Step 4: The ground broadband signal processing terminal sends the data output by the shaping filter unit to the digital-to-analog conversion unit to complete the digital-to-analog conversion of the signal, and then sends the signal to the satellite through the ground upconverter and the ground antenna;

[0011] Step 5: After the satellite antenna receives the uplink signal sent by the ground antenna, it is sent to the satellite downconverter to convert the signal to baseband, and then the analog-to-digital conversion of the signal is completed by the analog-to-digital conversion unit of the satellite broadband signal processing terminal;

[0012] Step 6, the satellite-borne broadband signal processing terminal sends the analog-to-digital converted signal to the matched filter unit, the timing recovery unit and the carrier recovery unit in sequence to complete the demodulation processing of the uplink signal;

[0013] Step 7, the data interception unit of the satellite-borne broadband signal processing terminal intercepts the data output by the carrier recovery unit;

[0014] Step 8: The framing unit of the satellite-borne broadband signal processing terminal performs a framing operation on the received service data and the intercepted symbol points. Specifically, when the framing unit inquires that the data interception unit has completed the interception of 4096 symbol data, it immediately starts the framing of the intercepted data after the current service data is sent. At this time, the received service data will be cached, and the service data will be sent after the framing of the intercepted data is completed.

[0015] Step 9, the encoding unit of the satellite-borne broadband signal processing terminal performs channel encoding on the data stream output by the framing unit;

[0016] Step 10: the shaping filter unit of the satellite-borne broadband signal processing terminal performs shaping filtering on the encoded data, and then sends the data to the digital-to-analog conversion unit to complete the digital-to-analog conversion of the signal, and then sends the signal to the ground through the satellite-borne upconverter and the satellite-borne antenna;

[0017] Step 11, the ground antenna receives the downlink signal sent by the satellite and transmits it to the ground downconverter, converts the signal to baseband, and then transmits it to the analog-to-digital conversion unit of the ground broadband signal processing terminal to complete the analog-to-digital conversion of the signal;

[0018] Step 12, the ground broadband signal processing terminal sends the analog-to-digital converted signal to the matched filter unit, the timing recovery unit, the carrier recovery unit and the decoding unit in sequence to complete the demodulation and decoding processing of the downlink signal;

[0019] Step 13, the data extraction unit of the ground broadband signal processing terminal extracts 4096 symbols inserted by the satellite broadband signal processing terminal from the decoded data in a timely manner;

[0020] Step 14, the time domain equalization unit of the ground broadband signal processing terminal performs time domain equalization processing on the 4096 symbols extracted by the data extraction unit;

[0021] Step 15, the ground broadband signal processing terminal updates the tap coefficients of the shaping filter unit according to the uplink distortion obtained by time domain equalization processing. After the tap coefficients of the shaping filter unit are updated, the default values ​​are no longer used when the coded data is shaped and filtered, but new tap coefficients are used. At this time, the signal sent by the ground broadband signal processing terminal will be distorted, thereby matching the distortion of the channel and compensating for the channel distortion.

[0022] Optionally, the channel coding method in step 2 and step 9 is LDPC coding, RS coding or Turbo coding.

[0023] Optionally, in step 7, the interception period is 1 second, and the number of intercepted symbols is 4096 symbols, where the symbol refers to a sample point with quantization information after timing recovery and carrier recovery.

[0024] A ground broadband signal processing terminal, comprising a framing unit, a coding unit, a shaping filter unit, a digital-to-analog conversion unit, an analog-to-digital conversion unit, a matched filter unit, a timing recovery unit, a carrier recovery unit, a decoding unit, a data extraction unit, and a time domain equalization unit;

[0025] When sending data, the framing unit of the ground broadband signal processing terminal performs framing operations on the received service data. When there is service data, the framing unit outputs a service frame, and when there is no service data, the framing unit outputs an empty frame, thereby ensuring that the output data stream is continuous;

[0026] The encoding unit of the ground broadband signal processing terminal performs channel encoding on the data stream output by the framing unit;

[0027] The shaping filter unit of the ground broadband signal processing terminal performs shaping filter processing on the encoded data. The tap coefficients of the shaping filter initially use default values ​​and do not pre-distort the output signal.

[0028] The ground broadband signal processing terminal sends the data output by the shaping filter unit to the digital-to-analog conversion unit to complete the digital-to-analog conversion of the signal, and then sends the signal to the satellite through the ground upconverter and ground antenna;

[0029] When receiving data, the ground antenna receives the downlink signal sent by the satellite and transmits it to the ground downconverter, which converts the signal to baseband and then transmits it to the analog-to-digital conversion unit of the ground broadband signal processing terminal to complete the analog-to-digital conversion of the signal;

[0030] The ground broadband signal processing terminal sends the analog-to-digital converted signal to the matched filter unit, timing recovery unit, carrier recovery unit and decoding unit in sequence to complete the demodulation and decoding processing of the downlink signal;

[0031] The data extraction unit of the ground broadband signal processing terminal extracts 4096 symbols inserted by the satellite broadband signal processing terminal from the decoded data in a timely manner;

[0032] The time domain equalization unit of the ground broadband signal processing terminal performs time domain equalization processing on the 4096 symbols extracted by the data extraction unit;

[0033] The ground broadband signal processing terminal updates the tap coefficients of the shaping filter unit according to the uplink distortion obtained by time domain equalization processing. After the tap coefficients of the shaping filter unit are updated, the default values ​​are no longer used when the coded data is shaped and filtered, but new tap coefficients are used. At this time, the signal sent by the ground broadband signal processing terminal will be distorted, thereby matching the distortion of the channel and compensating for the channel distortion.

[0034] A gateway broadband signal communication system comprises a satellite and a ground station, wherein the satellite comprises a satellite-borne broadband signal processing terminal, a satellite-borne upconverter, a satellite-borne downconverter, and a satellite-borne antenna, and the ground station comprises a ground-borne broadband signal processing terminal, a ground-borne upconverter, a ground-borne downconverter, and a ground antenna; the ground-borne broadband signal processing terminal comprises a framing unit, a coding unit, a shaping filter unit, a digital-to-analog conversion unit, an analog-to-digital conversion unit, a matched filtering unit, a timing recovery unit, a carrier recovery unit, a decoding unit, a data extraction unit, and a time domain equalization unit; the satellite-borne broadband signal processing terminal comprises an analog-to-digital conversion unit, a matched filtering unit, a timing recovery unit, a carrier recovery unit, a data interception unit, a framing unit, a coding unit, a shaping filter unit, and a digital-to-analog conversion unit;

[0035] When sending data, the framing unit of the ground broadband signal processing terminal performs framing operations on the received service data. When there is service data, the framing unit outputs a service frame, and when there is no service data, the framing unit outputs an empty frame, thereby ensuring that the output data stream is continuous;

[0036] The encoding unit of the ground broadband signal processing terminal performs channel encoding on the data stream output by the framing unit;

[0037] The shaping filter unit of the ground broadband signal processing terminal performs shaping filter processing on the encoded data. The tap coefficients of the shaping filter initially use default values ​​and do not pre-distort the output signal.

[0038] The ground broadband signal processing terminal sends the data output by the shaping filter unit to the digital-to-analog conversion unit to complete the digital-to-analog conversion of the signal, and then sends the signal to the satellite through the ground upconverter and ground antenna;

[0039] After the satellite antenna receives the uplink signal sent by the ground antenna, it is sent to the satellite downconverter to convert the signal to baseband, and then the analog-to-digital conversion of the signal is completed by the analog-to-digital conversion unit of the satellite broadband signal processing terminal;

[0040] The satellite-borne broadband signal processing terminal sends the analog-to-digital converted signal to the matched filter unit, timing recovery unit and carrier recovery unit in sequence to complete the demodulation processing of the uplink signal;

[0041] The data interception unit of the satellite-borne broadband signal processing terminal intercepts the data output by the carrier recovery unit, with an interception period of 1 second and an interception quantity of 4096 symbols; the symbol refers to a sample point with quantization information after timing recovery and carrier recovery;

[0042] The framing unit of the satellite-borne broadband signal processing terminal performs a framing operation on the received service data and the intercepted symbol points. Specifically, when the framing unit inquires that the data interception unit has completed the interception of 4096 symbol data, it immediately starts the framing of the intercepted data after the current service data is sent. At this time, the received service data will be cached, and the service data will be sent after the framing of the intercepted data is completed.

[0043] The encoding unit of the satellite-borne broadband signal processing terminal performs channel encoding on the data stream output by the framing unit;

[0044] The shaping filter unit of the satellite-borne broadband signal processing terminal performs shaping filtering on the encoded data, and then sends the data to the digital-to-analog conversion unit of the satellite-borne broadband signal processing terminal to complete the digital-to-analog conversion of the signal, and then sends the signal to the ground through the satellite-borne upconverter and the satellite-borne antenna;

[0045] When receiving data, the ground antenna receives the downlink signal sent by the satellite and transmits it to the ground downconverter, which converts the signal to baseband and then transmits it to the analog-to-digital conversion unit of the ground broadband signal processing terminal to complete the analog-to-digital conversion of the signal;

[0046] The ground broadband signal processing terminal sends the analog-to-digital converted signal to the matched filter unit, timing recovery unit, carrier recovery unit and decoding unit in sequence to complete the demodulation and decoding processing of the downlink signal;

[0047] The data extraction unit of the ground broadband signal processing terminal extracts 4096 symbols inserted by the satellite broadband signal processing terminal from the decoded data in a timely manner;

[0048] The time domain equalization unit of the ground broadband signal processing terminal performs time domain equalization processing on the 4096 symbols extracted by the data extraction unit;

[0049] The ground broadband signal processing terminal updates the tap coefficients of the shaping filter unit according to the uplink distortion obtained by time domain equalization processing. After the tap coefficients of the shaping filter unit are updated, the default values ​​are no longer used when the coded data is shaped and filtered, but new tap coefficients are used. At this time, the signal sent by the ground broadband signal processing terminal will be distorted, thereby matching the distortion of the channel and compensating for the channel distortion.

[0050] The present invention has the following beneficial effects:

[0051] 1. The present invention can pre-distort the transmitted signal on the ground to match the channel distortion and realize compensation for the channel distortion, thereby eliminating the digital equalizer with large resource consumption in the satellite baseband and significantly improving the weight, volume and power consumption of the satellite platform;

[0052] 2. The compensation for channel distortion in the present invention not only includes compensation for ground segment channel distortion, but also compensation for wireless channel and satellite platform channel distortion. It is a real compensation for full link distortion, and the compensation effect is better.

[0053] 3. The present invention monitors, calculates and compensates for channel distortion in seconds, achieving the effect of real-time pre-distortion;

[0054] 4. The present invention is applicable to both low-orbit feeder links and high-orbit feeder links. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 It is a schematic diagram of a broadband signal communication system of a gateway station;

[0056] Figure 2 It is a schematic diagram of the compensation link. DETAILED DESCRIPTION

[0057] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings.

[0058] A broadband signal communication system for a gateway station, such as Figure 1 As shown, it includes a satellite and a ground station, the satellite includes a satellite-borne broadband signal processing terminal, a satellite-borne upconverter, a satellite-borne downconverter, and a satellite-borne antenna, and the ground station includes a ground-based broadband signal processing terminal, a ground-based upconverter, a ground-based downconverter, and a ground antenna; the ground-based broadband signal processing terminal includes a framing unit, a coding unit, a shaping filter unit, a DA digital-to-analog conversion unit, an AD analog-to-digital conversion unit, a matching filter unit, a timing recovery unit, a carrier recovery unit, a decoding unit, a data extraction unit, and a time domain equalization unit; the satellite-borne broadband signal processing terminal includes an AD analog-to-digital conversion unit, a matching filter unit, a timing recovery unit, a carrier recovery unit, a data interception unit, a framing unit, a coding unit, a shaping filter unit, and a DA digital-to-analog conversion unit.

[0059] Based on this system, a broadband signal real-time digital predistortion method can be implemented. The specific steps are as follows:

[0060] Step 1: The ground broadband signal processing terminal performs a framing operation on the received service data. When there is service data, the framing unit outputs a service frame. When there is no service data, the framing unit outputs an empty frame. The framing unit ensures that the output data stream is continuous.

[0061] Step 2: The ground broadband signal processing terminal performs channel coding on the data stream output by the framing unit. The coding may adopt LDPC coding, RS coding, Turbo coding, etc., but is not limited to the above coding, and may be selected according to actual conditions;

[0062] Step 3: The ground broadband signal processing terminal performs shaping filtering on the encoded data. It should be noted that the tap coefficients of the shaping filter initially use default values, and the output signal will not be pre-distorted.

[0063] Step 4: The ground broadband signal processing terminal sends the shaped and filtered data to the DA to complete the digital-to-analog conversion of the signal, and then sends the signal to the satellite through the ground upconverter and ground antenna;

[0064] Step 5: After the satellite antenna receives the uplink signal sent by the ground station, it is sent to the satellite downconverter to convert the signal to baseband, and then the analog-to-digital conversion of the signal is completed through AD;

[0065] Step 6: The satellite-borne broadband signal processing terminal sends the analog-to-digital converted signal to the matched filtering, timing recovery and carrier recovery modules in sequence to complete the demodulation processing of the uplink signal;

[0066] Step 7: The data interception module of the satellite-borne broadband signal processing terminal intercepts the data after the carrier recovery, with an interception period of 1 second and an interception quantity of 4096 symbols; the so-called symbol is a sample point with quantization information after timing recovery and carrier recovery;

[0067] Step 8: The framing module of the satellite-borne broadband signal processing terminal performs framing operation on the received service data and the intercepted symbol points. It should be noted that when the framing module inquires that the data interception module has completed the interception of 4096 symbol data, it will immediately start the framing of the intercepted data after the current service data is sent. At this time, the received service data will be cached, and the service data will be sent after the framing of the intercepted data is completed;

[0068] Step 9: The satellite-borne broadband signal processing terminal performs channel coding on the data stream output by the framing unit. The coding may adopt LDPC coding, RS coding, Turbo coding, etc., but is not limited to the above coding, and may be selected according to actual conditions;

[0069] Step 10: The satellite-borne broadband signal processing terminal performs shaping filtering on the encoded data, and then sends the data to the DA to complete the digital-to-analog conversion of the signal, and then sends the signal to the ground through the satellite-borne upconverter and the satellite-borne antenna;

[0070] Step 11, after receiving the downlink signal sent by the satellite, the ground broadband signal processing terminal sends it to the ground down converter to convert the signal to baseband, and then completes the analog-to-digital conversion of the signal through AD;

[0071] Step 12, the ground broadband signal processing terminal sends the analog-to-digital converted signal to the matched filtering, timing recovery, carrier recovery and decoding module to complete the demodulation and decoding processing of the downlink signal;

[0072] Step 13, the ground broadband signal processing terminal extracts 4096 symbols inserted by the satellite broadband signal processing terminal from the decoded data in a timely manner;

[0073] Step 14, the ground broadband signal processing terminal performs time domain equalization processing on the extracted 4096 symbols;

[0074] Step 15, the ground broadband signal processing terminal updates the tap coefficients of the shaping filter according to the uplink distortion calculated by time domain equalization. After the shaping filter tap coefficients are updated, the data encoded by the ground broadband signal processing terminal is shaped and filtered no longer using the default values, but new tap coefficients. At this time, the signal sent by the ground broadband signal processing terminal will be distorted, thereby matching the distortion of the channel and compensating for the channel distortion.

[0075] In the present invention, the compensation for uplink distortion is completed in the ground broadband signal processing terminal. For the satellite-borne broadband signal processing terminal with limited power, volume and power consumption, there is no need to add a compensation module. It is only necessary to intercept a segment of the data after carrier recovery and frame it together with the service data and send it through the downlink. In addition, since the data for calculating the channel distortion is the carrier recovery data of the satellite-borne broadband signal processing terminal, the calculation of the channel distortion includes the ground segment channel distortion, the wireless channel distortion and the satellite platform channel distortion, such as Figure 2 As shown by the bold arrow in the middle, the full-link distortion is truly monitored and compensated.

[0076] In step 7 of the present invention, the data intercepted by the satellite broadband signal processing terminal is the data after timing recovery and carrier recovery. There is no need to demap the data after carrier recovery, and it can be directly intercepted. Therefore, the satellite broadband signal processing terminal in the present invention does not need to distinguish the modulation mode, and can be used for modulation modes such as BPSK, QPSK, 8PSK, 16APSK and 16QAM, but is not limited to the above modulation modes. It should be noted that the data interception of the present invention is continuous interception, that is, each time the data is intercepted, the data after carrier recovery is continuously sampled at 4096 points, and there can be no pause in the middle.

[0077] In step 15 of the present invention, the pre-distortion of the output signal is achieved by adjusting the tap coefficients of the shaping filter, rather than adding another stage of pre-distortion filtering after the shaping filter. This method combines two stages of multiplication-addition filtering into one stage of multiplication-addition filtering, and the ground broadband signal processing terminal saves a lot of logic resources.

[0078] In step 7 of the present invention, if the data capture is set to once per second, the monitoring, calculation and compensation of the channel distortion are all in seconds, achieving the effect of real-time pre-distortion. In addition, the data capture period in the present invention is not limited to once per second, and the data capture period can be increased or decreased as needed.

[0079] In summary, the present invention pre-distorts the signal sent from the ground to match the distortion of the channel and realizes compensation for the channel distortion. The satellite platform can save the digital equalizer which occupies a large amount of resources, and the weight, volume and power consumption of the satellite platform are significantly improved. Moreover, the satellite platform can respond to the channel distortion in a short time.

Claims

1. A broadband signal real-time digital predistortion method, characterized in that: The following steps are involved: Step 1: The framing unit of the ground broadband signal processing terminal performs a framing operation on the received service data. When there is service data, the framing unit outputs a service frame, and when there is no service data, the framing unit outputs an empty frame, thereby ensuring that the output data stream is continuous; Step 2, the encoding unit of the ground broadband signal processing terminal performs channel encoding on the data stream output by the framing unit; Step 3: The shaping filter unit of the ground broadband signal processing terminal performs shaping filter processing on the encoded data. The tap coefficients of the shaping filter initially use default values, and no pre-distortion is performed on the output signal. Step 4: The ground broadband signal processing terminal sends the data output by the shaping filter unit to the digital-to-analog conversion unit to complete the digital-to-analog conversion of the signal, and then sends the signal to the satellite through the ground upconverter and the ground antenna; Step 5: After the satellite antenna receives the uplink signal sent by the ground antenna, it is sent to the satellite downconverter to convert the signal to baseband, and then the analog-to-digital conversion of the signal is completed by the analog-to-digital conversion unit of the satellite broadband signal processing terminal; Step 6, the satellite-borne broadband signal processing terminal sends the analog-to-digital converted signal to the matched filter unit, the timing recovery unit and the carrier recovery unit in sequence to complete the demodulation processing of the uplink signal; Step 7, the data interception unit of the satellite-borne broadband signal processing terminal intercepts the data output by the carrier recovery unit, the interception period is 1 second, and 4096 symbols are continuously intercepted, wherein the symbol refers to a sample point with quantization information after timing recovery and carrier recovery; Step 8: The framing unit of the satellite-borne broadband signal processing terminal performs a framing operation on the received service data and the intercepted symbol points. Specifically, when the framing unit inquires that the data interception unit has completed the interception of 4096 symbol data, it immediately starts the framing of the intercepted data after the current service data is sent. At this time, the received service data will be cached, and the service data will be sent after the framing of the intercepted data is completed. Step 9, the encoding unit of the satellite-borne broadband signal processing terminal performs channel encoding on the data stream output by the framing unit; Step 10, the shaping filter unit of the satellite-borne broadband signal processing terminal performs shaping filter processing on the encoded data, and then sends the data to the digital-to-analog conversion unit to complete the digital-to-analog conversion of the signal, and then sends the signal to the ground through the satellite-borne upconverter and the satellite-borne antenna; Step 11, the ground antenna receives the downlink signal sent by the satellite and transmits it to the ground downconverter, converts the signal to baseband, and then transmits it to the analog-to-digital conversion unit of the ground broadband signal processing terminal to complete the analog-to-digital conversion of the signal; Step 12, the ground broadband signal processing terminal sends the analog-to-digital converted signal to the matched filter unit, the timing recovery unit, the carrier recovery unit and the decoding unit in sequence to complete the demodulation and decoding processing of the downlink signal; Step 13, the data extraction unit of the ground broadband signal processing terminal extracts 4096 symbols inserted by the satellite broadband signal processing terminal from the decoded data in a timely manner; Step 14, the time domain equalization unit of the ground broadband signal processing terminal performs time domain equalization processing on the 4096 symbols extracted by the data extraction unit; Step 15, the ground broadband signal processing terminal updates the tap coefficients of the shaping filter unit of the ground broadband signal processing terminal according to the uplink distortion obtained by time domain equalization processing. After the tap coefficients of the shaping filter unit are updated, the default values ​​are no longer used when the coded data is shaped and filtered, but new tap coefficients are used. At this time, the signal sent by the ground broadband signal processing terminal will be distorted, thereby matching the distortion of the channel and compensating for the channel distortion.

2. A broadband signal real-time digital predistortion method according to claim 1, characterized in that: The channel coding method in step 2 and step 9 is LDPC coding, RS coding or Turbo coding.

3. A gateway broadband signal communication system, characterized in that: It includes a satellite and a ground station, wherein the satellite includes a satellite-borne broadband signal processing terminal, a satellite-borne upconverter, a satellite-borne downconverter, and a satellite-borne antenna, and the ground station includes a ground-based broadband signal processing terminal, a ground-based upconverter, a ground-based downconverter, and a ground-based antenna; the ground-based broadband signal processing terminal includes a framing unit, a coding unit, a shaping filter unit, a digital-to-analog conversion unit, an analog-to-digital conversion unit, a matching filter unit, a timing recovery unit, a carrier recovery unit, a decoding unit, a data extraction unit, and a time domain equalization unit; the satellite-borne broadband signal processing terminal includes an analog-to-digital conversion unit, a matching filter unit, a timing recovery unit, a carrier recovery unit, a data interception unit, a framing unit, a coding unit, a shaping filter unit, and a digital-to-analog conversion unit; When sending data, the framing unit of the ground broadband signal processing terminal performs framing operations on the received service data. When there is service data, the framing unit outputs a service frame, and when there is no service data, the framing unit outputs an empty frame, thereby ensuring that the output data stream is continuous; The encoding unit of the ground broadband signal processing terminal performs channel encoding on the data stream output by the framing unit; The shaping filter unit of the ground broadband signal processing terminal performs shaping filter processing on the encoded data. The tap coefficients of the shaping filter initially use default values ​​and do not pre-distort the output signal. The ground broadband signal processing terminal sends the data output by the shaping filter unit to the digital-to-analog conversion unit to complete the digital-to-analog conversion of the signal, and then sends the signal to the satellite through the ground upconverter and ground antenna; After the satellite antenna receives the uplink signal sent by the ground antenna, it is sent to the satellite downconverter to convert the signal to baseband, and then the analog-to-digital conversion of the signal is completed by the analog-to-digital conversion unit of the satellite broadband signal processing terminal; The satellite-borne broadband signal processing terminal sends the analog-to-digital converted signal to the matched filter unit, timing recovery unit and carrier recovery unit in sequence to complete the demodulation processing of the uplink signal; The data interception unit of the satellite-borne broadband signal processing terminal intercepts the data output by the carrier recovery unit, with an interception period of 1 second, and continuously intercepts 4096 symbols; the symbol refers to a sample point with quantization information after timing recovery and carrier recovery; The framing unit of the satellite-borne broadband signal processing terminal performs a framing operation on the received service data and the intercepted symbol points. Specifically, when the framing unit inquires that the data interception unit has completed the interception of 4096 symbol data, it immediately starts the framing of the intercepted data after the current service data is sent. At this time, the received service data will be cached, and the service data will be sent after the framing of the intercepted data is completed. The encoding unit of the satellite-borne broadband signal processing terminal performs channel encoding on the data stream output by the framing unit; The shaping filter unit of the satellite-borne broadband signal processing terminal performs shaping filtering on the encoded data, and then sends the data to the digital-to-analog conversion unit of the satellite-borne broadband signal processing terminal to complete the digital-to-analog conversion of the signal, and then sends the signal to the ground through the satellite-borne upconverter and the satellite-borne antenna; When receiving data, the ground antenna receives the downlink signal sent by the satellite and transmits it to the ground downconverter, which converts the signal to baseband and then transmits it to the analog-to-digital conversion unit of the ground broadband signal processing terminal to complete the analog-to-digital conversion of the signal; The ground broadband signal processing terminal sends the analog-to-digital converted signal to the matched filter unit, timing recovery unit, carrier recovery unit and decoding unit in sequence to complete the demodulation and decoding processing of the downlink signal; The data extraction unit of the ground broadband signal processing terminal extracts 4096 symbols inserted by the satellite broadband signal processing terminal from the decoded data in a timely manner; The time domain equalization unit of the ground broadband signal processing terminal performs time domain equalization processing on the 4096 symbols extracted by the data extraction unit; The ground broadband signal processing terminal updates the tap coefficients of the shaping filter unit of the ground broadband signal processing terminal according to the uplink distortion obtained by time domain equalization processing. After the tap coefficients of the shaping filter unit are updated, the default values ​​are no longer used when the coded data is shaped and filtered, but new tap coefficients are used. At this time, the signal sent by the ground broadband signal processing terminal will be distorted, thereby matching the distortion of the channel and realizing compensation for the channel distortion.

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