Dynamic Power Back-Off for AGC-DPD I/Q Signal Linearity
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Solution Overview
Problem
The existing CPRI transmission systems face challenges in effectively improving the IMD3 spectrum performance and EVM performance of I/Q signals due to the non-linearity of power amplifiers, which is exacerbated by real-time changes in CPRI I/Q traffic.
Innovation Solution
A power adjustment method and apparatus that performs automatic gain control and digital pre-distortion processing on the to-be-output signal, calculates an output power back-off value based on the gain value, and adjusts the output power in real-time to reduce non-linearity, thereby enhancing the IMD3 spectrum and EVM performance of the I/Q signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed back-off is performed on output power of the power amplifier, then the non-linearity of the power amplifier is reduced and the IMD3 spectrum performance and EVM performance are improved, but the output power cannot be adjusted in real-time to match changing CPRI I/Q traffic conditions
Solution Approach 1:
The patent implements dynamic output power adjustment by calculating an OBO value based on real-time gain values obtained from AGC processing of CPRI I/Q traffic. This allows the power amplifier's output power to be continuously adapted to matching traffic conditions, resolving the contradiction between maintaining fixed back-off for performance and enabling real-time adjustment for adaptability.
Solution Approach 2:
The system employs feedback mechanisms where the gain value from AGC processing is used to calculate the OBO value, which then controls the output power adjustment. This closed-loop feedback ensures that the power amplifier operates optimally under varying traffic conditions while maintaining improved IMD3 and EVM performance.
2Length of moving object
If output power is increased to extend microwave transmission distance, then the transmission distance is increased, but the non-linearity of the power amplifier is exacerbated and the IMD3 spectrum performance deteriorates
Solution Approach 1:
The patent changes the operating parameters of the power amplifier by dynamically adjusting the output power based on calculated OBO values. This allows the system to optimize the balance between transmission distance and signal quality by adjusting power levels according to real-time traffic conditions and amplifier characteristics.
Data Source
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AI summary
This application provides a power adjustment method and apparatus, where the method includes: obtaining a to-be-output signal; performing first automatic gain control AGC processing on the to-be-output signal to obtain the to-be-output signal on which the first AGC processing is performed, and to obtain a gain value of the to-be-output signal; performing digital pre-distortion DPD processing on the to-be-output signal on which the first AGC processing is performed, to obtain the to-be-output signal on which the DPD processing is performed; calculating an output power back-off OBO value based on the gain value; adjusting, based on the OBO value, output power of the to-be-output signal on which the DPD processing is performed; and sending, to a signal receive end, the to-be-output signal on which the power adjustment is performed. According to the power adjustment method and apparatus in the embodiments of this application, the IMD3 spectrum performance and the EVM performance of an I/Q signal can be improved.