Antenna Module Digital Pre-Distortion for mmWave PA Linearity
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Solution Overview
Problem
The linearity of power amplifiers in mm-Wave band 5G communication systems is compromised when input signal magnitudes exceed a certain threshold, leading to gain compression and reduced performance.
Innovation Solution
Implementing digital pre-distortion (DPD) in the baseband digital domain to compensate for the compressed gain of power amplifiers by applying distortion that maintains signal linearity across varying input levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the input signal magnitude is increased to improve transmission rate, then the transmission rate is improved, but the linearity of the power amplifier deteriorates and gain compression occurs
Solution Approach 1:
The patent applies digital pre-distortion (DPD) technology that performs distortion compensation in advance before the signal reaches the power amplifier. By pre-applying the opposite distortion characteristics to the input signal, the system compensates for the expected non-linear behavior of the PA, thereby maintaining output signal linearity even when operating at high input signal magnitudes required for high transmission rates
Solution Approach 2:
The patent implements a feedback mechanism where the actual output signal characteristics are measured and used to generate correction signals that counteract the non-linear distortion. The system continuously adjusts the pre-distortion parameters based on measured PA characteristics, applying anti-action to compensate for gain compression and maintain linearity during high-power transmission operations
2Reliability
If digital pre-distortion is applied to maintain signal linearity, then signal linearity is improved, but the device complexity increases
Solution Approach 1:
The patent replaces complex hardware-based linearization techniques with software-based digital signal processing algorithms. By implementing DPD entirely in the digital domain using baseband processing, the system achieves power amplifier linearization without requiring additional analog components or hardware modifications, thereby maintaining signal linearity while minimizing device complexity
Solution Approach 2:
The patent dynamically adjusts digital signal parameters such as distortion coefficients, gain values, and phase corrections based on measured power amplifier characteristics. By changing these software parameters adaptively rather than requiring fixed hardware configurations, the system maintains signal linearity across varying operating conditions while keeping the device structure relatively simple
Data Source
AI summary
An antenna module may include antennas, RF chains connected to the antennas, a splitter/combiner connected to the RF chains, a mixer configured to upconvert an IF signal input to the antenna module into a transmission RF signal and output the upconverted signal to the splitter/combiner and/or to downconvert a reception RF signal which is a combination of signals from the RF chains provided from the splitter/combiner, a plurality of first couplers connected between the RF chains and the antennas, a second coupler for measuring a magnitude corresponding to a transmission RF signal before split by the splitter/combiner and/or the reception RF signal combined by the splitter/combiner, and a power detector configured to provide a plurality of magnitudes of a plurality of signals from the plurality of first couplers and a magnitude of a signal from the second coupler.