Digital Predistortion Gain Holding for Large Dynamic Range Signals
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Solution Overview
Problem
The existing power amplifier systems face reduced power efficiency due to the need for peak suppression before digital predistortion (DPD), which increases power consumption and reduces overall efficiency, especially when dealing with transmission signals having a large dynamic range.
Innovation Solution
A distortion compensation apparatus and method that determines whether the transmission signal power is below a threshold, holding or updating distortion compensation gains only when the power is below this threshold, allowing for efficient distortion compensation without peak suppression, even for signals with large dynamic ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If peak suppression is performed before digital predistortion to handle transmission signals with large dynamic range, then distortion compensation performance is improved, but power consumption increases and power efficiency decreases
Solution Approach 1:
The patent changes the parameter of distortion compensation coefficient update timing based on signal power levels. Instead of continuously updating coefficients (which consumes power), the system updates coefficients only when signal power is below a threshold, and uses held coefficients when power exceeds the threshold. This parameter-based conditional updating resolves the contradiction by maintaining compensation performance for large dynamic range signals while reducing power consumption through selective coefficient updates.
2Measurement precision
If distortion compensation coefficients are continuously updated to compensate for environmental variations, then compensation accuracy is improved, but processing complexity and power consumption increase
Solution Approach 1:
The patent implements periodic action by updating distortion compensation coefficients only at specific intervals when signal power conditions are met (below threshold), rather than continuously. The system holds coefficients between update periods, creating a periodic update pattern that maintains compensation accuracy for environmental variations while reducing processing complexity and power consumption compared to continuous updating.
Data Source
AI summary
A distortion compensation apparatus executes a process including: Performing distortion compensation that compensates in advance for a nonlinear distortion occurring when a transmission signal is amplified by a power amplifier; determining whether power of the transmission signal is smaller than a predetermined threshold; holding a gain relating to the distortion compensation or a result of the distortion compensation when the power of the transmission signal is determined to be smaller than the predetermined threshold; and outputting to the power amplifier, when the power of the transmission signal is determined to be smaller than the predetermined threshold, the result of the distortion compensation, and outputting to the power amplifier, when the power of the transmission signal is determined to be equal to or greater than the predetermined threshold, a result of distortion compensation performed using the held, gain, or the held result of the distortion compensation.