A DPD performance verification system and method based on a feedback channel

Abstract

The application relates to a DPD performance verification system based on a feedback channel, which comprises a baseband signal generation module, a DPD data processing module, a DPD coefficient calculation module, a transceiver and a power amplifier. The baseband signal generation module generates a digital baseband signal and inputs the digital baseband signal to the DPD data processing module. When the digital baseband signal is input for the first time, no feedback is provided. The DPD data processing module loads the digital baseband signal to the transceiver through FPGA on one hand, and inputs the power amplifier pre-signal converted from the digital baseband signal to the frequency domain to the DPD coefficient calculation module on the other hand. The application can provide DPD function simulation for the transceiver without DPD function configuration, and can complete the DPD performance test of the transceiver receiving feedback channels with the advantages of high efficiency and low cost.

Description

Technical Field

[0001] This invention relates to a DPD performance verification system and method based on a feedback path, belonging to the field of radio frequency transceiver performance verification technology. Background Technology

[0002] With the development of technologies such as orthogonal amplitude modulation (OAM), orthogonal frequency division multiplexing (OFDM), and code division multiple access (CDMA), frequency utilization has been greatly improved. However, these modulation methods increase the peak-to-average power ratio (PAPR) of the signal, resulting in severe memory nonlinear distortion while amplifying the signal power. Digital predistortion, with its advantages of high efficiency and ease of engineering implementation, has become a common method for solving this problem.

[0003] Digital predistortion (DPD) is a calibration function applied to radio frequency transceivers, enabling users to achieve higher power amplification efficiency while meeting adjacent channel leakage rate (ACLR) requirements for transmitted or received signals, in order to comply with 3GPP standards for LTE and other technologies. It works by predistorting the transmitted signal data to eliminate distortion caused by the nonlinearity of the power amplifier.

[0004] Transceivers typically have a transmit channel, a receive channel, and a receive observation channel. The observation receiver provides the input feedback path for digital predistortion data. However, in practice, it has been found that the transceiver only provides a calibration feedback channel and does not actually possess digital predistortion functionality. To verify the performance of this feedback path, an external digital predistortion signal processing system suitable for the programmable RF transceiver needs to be built to further verify the transceiver's performance. Currently, no such solution has been proposed. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a DPD performance verification system based on feedback path, which solves the problems of numerous devices, complex operation and high cost in the performance verification of transceiver feedback channels, thereby greatly improving the testing efficiency of radio frequency transceivers.

[0006] The solution of the present invention is as follows:

[0007] A DPD performance verification system based on a feedback path includes a baseband signal generation module, a DPD data processing module, a DPD coefficient calculation module, a transceiver, and a power amplifier.

[0008] The baseband signal generation module generates a digital baseband signal and inputs it to the DPD data processing module. There is no feedback when it is input for the first time. The DPD data processing module loads the digital baseband signal into the transceiver through the FPGA on the one hand, and inputs the power amplifier signal after converting the digital baseband signal to the frequency domain to the DPD coefficient calculation module on the other hand.

[0009] The digital baseband signal transmitted by the transceiver is amplified by the power amplifier and then received by the transceiver's receiving feedback channel. The amplified signal is then amplified by the FPGA and input into the DPD coefficient calculation module, which finally outputs the DPD-corrected signal data.

[0010] The DPD coefficient calculation module performs compensation calculations based on the pre-amplifier signal and the post-amplifier signal, and feeds the results back to the DPD data processing module. The DPD data processing module performs pre-distortion processing on the baseband signal, thereby realizing DPD closed-loop iteration. After the iteration is completed, the pre-distorted signal is output and amplified by an amplifier to form the final signal spectrum. The signal spectrum is analyzed to obtain the quantization index value, thereby judging the performance of the transceiver feedback path.

[0011] Furthermore, the DPD data processing module can customize various digital predistortion algorithms. It does not process the baseband signal input when it is received for the first time. After receiving the feedback signal, it performs digital predistortion processing on the baseband signal according to the feedback information to generate predistorted baseband signal data. This data is then loaded into the transceiver through the FPGA for transmission.

[0012] Furthermore, the DPD coefficient calculation module requires two signal inputs: one is the predistorted signal generated by the DPD data processing module, which is transformed into spectrum data by Fourier transform; the other is the amplified signal received back by the transceiver feedback path after the predistorted signal generated by the DPD data processing module is transmitted and amplified by the transceiver.

[0013] Furthermore, the DPD coefficients in the DPD coefficient calculation module are used to determine whether a satisfactory predistorted baseband signal has been obtained or whether the predetermined number of cycles has been reached. If a satisfactory predistorted baseband signal has not been obtained, the next round of predistortion optimization is performed. If a satisfactory predistorted baseband signal has been obtained or the predetermined number of cycles has been reached, the corrected signal data is output and the iteration stops.

[0014] Furthermore, the baseband signal generation module is connected to the DPD data processing module, the DPD data processing module is connected to the transceiver, the transceiver hardware transmitter and the observation receiver are connected to the power amplifier, the transceiver hardware is connected to the DPD coefficient calculation module, and the DPD coefficient calculation module is connected to the DPD data processing module.

[0015] A DPD performance verification method based on feedback paths, comprising the following steps:

[0016] S1, The baseband signal generation module generates a digital baseband signal and inputs it to the DPD data processing module. There is no feedback when it is input for the first time.

[0017] The S2 and DPD data processing modules load the digital baseband signal into the transceiver via the FPGA, and input the power amplifier signal after converting the digital baseband signal to the frequency domain into the DPD coefficient calculation module.

[0018] S3. The digital baseband signal transmitted by the transceiver is amplified by the power amplifier and then received by the transceiver's receiving feedback channel. The amplified signal is then amplified by the FPGA and input into the DPD coefficient calculation module, which finally outputs the DPD-corrected signal data.

[0019] S4, the DPD coefficient calculation module performs compensation calculations based on the pre-amplifier signal and the post-amplifier signal, and feeds the results back to the DPD data processing module. The DPD data processing module performs pre-distortion processing on the baseband signal, thereby realizing DPD closed-loop iteration.

[0020] S5. After the iteration is completed, the pre-distorted signal is output and amplified by an amplifier to form the final signal spectrum. The signal spectrum is analyzed to obtain the quantization index value, thereby judging the performance of the transceiver feedback path.

[0021] The advantages of this invention compared to the prior art are:

[0022] (1) The DPD coefficient calculation module of the present invention is connected to the transmitting channel and the feedback receiving channel of the transceiver under test. Only an external power amplifier is connected between the transmitting end and the feedback receiving end of the transceiver under test. It is suitable for various transceiver performance tests. No modification to the hardware design of the transceiver under test is required. It solves the problems of high difficulty and high cost in hardware implementation of DPD.

[0023] (2) This invention can provide DPD function simulation for transceivers that are not configured with DPD function, and complete the DPD performance test of the transceiver receiving feedback channel with the advantages of high efficiency and low cost. Attached Figure Description

[0024] Figure 1 This is a flowchart of a DPD performance verification system based on a feedback path, as described in an embodiment of the present invention.

[0025] Figure 2 This is a comparison diagram of the initial signal spectrum of the undistorted transmitted signal after passing through an amplifier and the final signal spectrum of the predistorted signal after passing through an amplifier, obtained by a DPD performance verification system based on a feedback path in an embodiment of the present invention. Detailed Implementation

[0026] The present invention will be further described below with reference to the embodiments.

[0027] like Figure 1 , 2As shown, a DPD performance verification system based on a feedback path includes a baseband signal generation module, a DPD data processing module, a DPD coefficient calculation module, a transceiver, and a power amplifier.

[0028] The baseband signal generation module generates a digital baseband signal and inputs it to the DPD data processing module. There is no feedback when it is input for the first time. The DPD data processing module loads the digital baseband signal into the transceiver through the FPGA on the one hand, and inputs the power amplifier signal after converting the digital baseband signal to the frequency domain to the DPD coefficient calculation module on the other hand.

[0029] The digital baseband signal transmitted by the transceiver is amplified by the power amplifier and then received by the transceiver's receiving feedback channel. The amplified signal is then amplified by the FPGA and input into the DPD coefficient calculation module, which finally outputs the DPD-corrected signal data.

[0030] The DPD coefficient calculation module performs compensation calculations based on the pre-amplifier signal and the post-amplifier signal, and feeds the results back to the DPD data processing module. The DPD data processing module performs pre-distortion processing on the baseband signal, thereby realizing DPD closed-loop iteration. After the iteration is completed, the pre-distorted signal is output and amplified by an amplifier to form the final signal spectrum. The signal spectrum is analyzed to obtain the quantization index value, thereby judging the performance of the transceiver feedback path.

[0031] Furthermore, the DPD data processing module can customize various digital predistortion algorithms. It does not process the baseband signal input when it is received for the first time. After receiving the feedback signal, it performs digital predistortion processing on the baseband signal according to the feedback information to generate predistorted baseband signal data. This data is then loaded into the transceiver through the FPGA for transmission.

[0032] Furthermore, the DPD coefficient calculation module requires two signal inputs: one is the predistorted signal generated by the DPD data processing module, which is transformed into spectrum data by Fourier transform; the other is the amplified signal received back by the transceiver feedback path after the predistorted signal generated by the DPD data processing module is transmitted and amplified by the transceiver.

[0033] Furthermore, the DPD coefficients in the DPD coefficient calculation module are used to determine whether a satisfactory predistorted baseband signal has been obtained or whether the predetermined number of cycles has been reached. If a satisfactory predistorted baseband signal has not been obtained, the next round of predistortion optimization is performed. If a satisfactory predistorted baseband signal has been obtained or the predetermined number of cycles has been reached, the corrected signal data is output and the iteration stops.

[0034] Furthermore, the baseband signal generation module is connected to the DPD data processing module, the DPD data processing module is connected to the transceiver, the transceiver hardware transmitter and the observation receiver are connected to the power amplifier, the transceiver hardware is connected to the DPD coefficient calculation module, and the DPD coefficient calculation module is connected to the DPD data processing module.

[0035] A DPD performance verification method based on feedback paths, comprising the following steps:

[0036] S1, The baseband signal generation module generates a digital baseband signal and inputs it to the DPD data processing module. There is no feedback when it is input for the first time.

[0037] The S2 and DPD data processing modules load the digital baseband signal into the transceiver via the FPGA, and input the power amplifier signal after converting the digital baseband signal to the frequency domain into the DPD coefficient calculation module.

[0038] S3. The digital baseband signal transmitted by the transceiver is amplified by the power amplifier and then received by the transceiver's receiving feedback channel. The amplified signal is then amplified by the FPGA and input into the DPD coefficient calculation module, which finally outputs the DPD-corrected signal data.

[0039] S4, the DPD coefficient calculation module performs compensation calculations based on the pre-amplifier signal and the post-amplifier signal, and feeds the results back to the DPD data processing module. The DPD data processing module performs pre-distortion processing on the baseband signal, thereby realizing DPD closed-loop iteration.

[0040] S5. After the iteration is completed, the pre-distorted signal is output and amplified by an amplifier to form the final signal spectrum. The signal spectrum is analyzed to obtain the quantization index value, thereby judging the performance of the transceiver feedback path.

[0041] The DPD coefficient calculation module of this invention is connected to the transmitting channel and the feedback receiving channel of the transceiver under test. Only an external power amplifier is connected between the transmitting end and the feedback receiving end of the transceiver under test. It is suitable for various transceiver performance tests, without the need to modify the hardware design of the transceiver under test, and solves the problems of high difficulty and high cost in hardware implementation of DPD.

[0042] This invention can provide DPD function simulation for transceivers without DPD function, and complete the DPD performance test of the transceiver's receive feedback channel with high efficiency and low cost.

[0043] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A DPD performance verification system based on a feedback path, characterized in that, It includes a baseband signal generation module, a DPD data processing module, a DPD coefficient calculation module, a transceiver, and a power amplifier; The baseband signal generation module generates a digital baseband signal and inputs it to the DPD data processing module. There is no feedback when it is input for the first time. The DPD data processing module loads the digital baseband signal into the transceiver through the FPGA on the one hand, and inputs the power amplifier signal after converting the digital baseband signal to the frequency domain to the DPD coefficient calculation module on the other hand. The digital baseband signal transmitted by the transceiver is amplified by the power amplifier and then received by the transceiver's feedback channel. The amplified signal is then amplified by the FPGA and input into the DPD coefficient calculation module, which finally outputs the DPD-corrected signal data. The DPD coefficient calculation module performs compensation calculations based on the pre-amplifier signal and the post-amplifier signal, and feeds the results back to the DPD data processing module. The DPD data processing module performs pre-distortion processing on the baseband signal, thereby realizing DPD closed-loop iteration. After the iteration is completed, the pre-distorted signal is output and amplified by an amplifier to form the final signal spectrum. The signal spectrum is analyzed to obtain the quantization index value, thereby judging the performance of the transceiver feedback path. The DPD coefficient calculation module determines whether a satisfactory predistorted baseband signal has been obtained or the predetermined number of iterations has been reached. If a satisfactory predistorted baseband signal has not been obtained, the next round of predistortion optimization is performed. If a satisfactory predistorted baseband signal has been obtained or the predetermined number of iterations has been reached, the corrected signal data is output and the iteration stops. The baseband signal generation module is connected to the DPD data processing module; The DPD data processing module is connected to the input of the transceiver hardware transmit channel via the FPGA, and the transmit end of the transceiver hardware transmit channel is connected to the input of the power amplifier. The receiver of the transceiver hardware feedback channel is connected to the output of the power amplifier, and the output of the transceiver hardware feedback channel is connected to the DPD coefficient calculation module through the FPGA. The DPD coefficient calculation module is connected to the DPD data processing module; Only an external power amplifier is connected between the transmitting end of the hardware transmission channel of the transceiver under test and the receiving end of the hardware feedback channel of the transceiver. The DPD performance verification system is used to provide DPD function simulation for transceivers that are not configured with DPD function, and to complete the DPD performance test of the transceiver feedback channel.

2. The DPD performance verification system based on a feedback path according to claim 1, characterized in that, The DPD data processing module has a variety of custom digital predistortion algorithms. It does not process the baseband signal input when it is received for the first time. After receiving the feedback signal, it performs digital predistortion processing on the baseband signal according to the feedback information to generate predistorted baseband signal data. This data is then loaded into the transceiver through the FPGA for transmission.

3. The DPD performance verification system based on a feedback path according to claim 1, characterized in that, The DPD coefficient calculation module requires two signal inputs: one is the predistorted signal generated by the DPD data processing module, which is transformed into spectrum data by Fourier transform; the other is the amplified signal received back by the transceiver feedback channel after the predistorted signal generated by the DPD data processing module is transmitted and amplified by the transceiver.

4. A DPD performance verification method based on feedback paths, characterized in that the steps are as follows: include: S1, The baseband signal generation module generates a digital baseband signal and inputs it to the DPD data processing module. There is no feedback when it is input for the first time. The S2 and DPD data processing modules load the digital baseband signal into the transceiver via the FPGA, and input the power amplifier signal after converting the digital baseband signal to the frequency domain into the DPD coefficient calculation module. S3. The digital baseband signal transmitted by the transceiver is amplified by the power amplifier and then received by the feedback channel of the transceiver. The amplified signal is then amplified by the FPGA and input into the DPD coefficient calculation module, which finally outputs the DPD-corrected signal data. S4, the DPD coefficient calculation module performs compensation calculations based on the pre-amplifier signal and the post-amplifier signal, and feeds the results back to the DPD data processing module. The DPD data processing module performs pre-distortion processing on the baseband signal, thereby realizing DPD closed-loop iteration. S5. After the iteration is completed, the predistorted signal is output and amplified by an amplifier to form the final signal spectrum; the signal spectrum is analyzed to obtain the quantization index value, thereby judging the performance of the transceiver feedback path. The DPD coefficient calculation module determines whether a satisfactory predistorted baseband signal has been obtained or the predetermined number of iterations has been reached. If a satisfactory predistorted baseband signal has not been obtained, the next round of predistortion optimization is performed. If a satisfactory predistorted baseband signal has been obtained or the predetermined number of iterations has been reached, the corrected signal data is output and the iteration stops. The baseband signal generation module is connected to the DPD data processing module. The DPD data processing module is connected to the input of the transceiver hardware transmit channel via the FPGA, and the transmit end of the transceiver hardware transmit channel is connected to the input of the power amplifier. The receiver of the transceiver hardware feedback channel is connected to the output of the power amplifier, and the output of the transceiver hardware feedback channel is connected to the DPD coefficient calculation module through the FPGA. The DPD coefficient calculation module is connected to the DPD data processing module; Only an external power amplifier is connected between the transmitting end of the hardware transmission channel of the transceiver under test and the receiving end of the hardware feedback channel of the transceiver. The DPD performance verification method is used to provide DPD function simulation for transceivers that are not configured with DPD function, and to complete the DPD performance test of the transceiver feedback channel.

5. The DPD performance verification method based on a feedback path according to claim 4, characterized in that, The DPD data processing module has a variety of custom digital predistortion algorithms. It does not process the baseband signal input when it is received for the first time. After receiving the feedback signal, it performs digital predistortion processing on the baseband signal according to the feedback information to generate predistorted baseband signal data. This data is then loaded into the transceiver through the FPGA for transmission.

6. The DPD performance verification method based on a feedback path according to claim 4, characterized in that, The DPD coefficient calculation module requires two signal inputs: one is the predistorted signal generated by the DPD data processing module, which is transformed into spectrum data by Fourier transform; the other is the amplified signal received back by the transceiver feedback channel after the predistorted signal generated by the DPD data processing module is transmitted and amplified by the transceiver.

Images