Configurable Nonlinear DPD Filter for Charge-Trapping Compensation
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Solution Overview
Problem
Radio frequency communication systems face challenges in compensating for transient non-ideal behaviors in power amplifiers, particularly due to charge trapping effects that affect device characteristics such as threshold voltage and drain current, which existing technologies have not adequately addressed.
Innovation Solution
A digital pre-distortion (DPD) system with a configurable non-linear filter, such as a Laguerre filter, is implemented to account for charge trapping effects by using decimation ratios, crossbar switches, and programmable coefficients, allowing for flexible compensation across various time ranges and frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed non-linear filter is used in the DPD system, then the device complexity is reduced, but the adaptability to compensate for charge trapping effects across different time ranges is insufficient
Solution Approach 1:
The patent implements a configurable non-linear filter where the decimation ratio can be dynamically adjusted based on the specific charge trapping effects being compensated. The filter structure allows dynamic reconfiguration of its parameters (decimation ratio, coefficients) to adapt to different time ranges and trapping characteristics, transforming a static filter into a dynamic one that can respond to varying operational conditions.
Solution Approach 2:
The configurable non-linear filter is designed to serve multiple functions: it can compensate for charge trapping effects across different time ranges (from microseconds to milliseconds), work with various decimation ratios, and handle different rows of the filter with different configurations. This multi-functionality allows a single filter structure to address diverse compensation needs without requiring separate dedicated filters for each scenario.
2Adaptability or versatility
If multiple decimation ratios and configurable rows are implemented, then the compensation flexibility is improved, but the device complexity increases
Solution Approach 1:
The non-linear filter is segmented into multiple rows, where each row can be independently configured with different decimation ratios and coefficients. This segmentation allows the system to process different aspects of the charge trapping effects in parallel, with each row handling specific time ranges or frequency characteristics, thereby improving compensation flexibility while maintaining manageable complexity through modular organization.
Data Source
Figure 1A
Figure 1B~1C
Figure 2A
AI summary
Some embodiments herein describe a radio frequency communication system that can include a transmitter to output an radio frequency (RF) transmit signal, the transmitter including a digital pre-distortion system (DPD) that pre-distorts the RF transmit signal. The DPD system can include a configurable non-linear filter, such as a Laguerre filter, having multiple rows where at least one row operates with a configurable decimation ratio. The DPD system can further include decimators and a crossbar switch coupled between the decimators.