Shared Receiver Path for DPD Feedback in TDD Power Amplifiers
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Solution Overview
Problem
Conventional wireless devices face complexity and inefficiency in implementing digital pre-distortion (DPD) filters to compensate for nonlinear power amplifier noise, requiring specialized hardware and additional computational resources and board space for feedback signal processing.
Innovation Solution
A time division duplexing (TDD) configured radio frame is used to provide both feedback signals and wireless transmission signals through a single receiver path, allowing efficient use of resources by activating a switch to route feedback through the receiver path during uplink time periods and deactivating it during downlink periods, enabling the coefficient calculator to optimize DPD filter coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single receiver path is used to process both feedback signals and wireless transmission signals, then device complexity and board space are reduced, but it becomes difficult to efficiently process feedback signals during uplink periods while receiving signals during downlink periods
Solution Approach 1:
The patent applies dynamics by making the receiver path configuration changeable through a switch that dynamically routes signals based on time period. During uplink periods, the switch connects the receiver path to process feedback signals, while during downlink periods, it connects to receive wireless transmission signals. This dynamic reconfiguration allows a single receiver path to efficiently handle different signal types at different times, reducing device complexity while maintaining ease of operation.
Solution Approach 2:
The patent implements periodic action by utilizing time division duplexing (TDD) configured radio frames that periodically alternate between uplink and downlink periods. The receiver path is periodically activated for feedback signal processing during uplink periods and deactivated during downlink periods. This periodic switching enables efficient resource utilization, allowing the same hardware path to serve multiple functions without interference, thereby reducing complexity while preserving operational efficiency.
2Measurement precision
If specialized hardware is implemented for DPD filter coefficient calculation and feedback processing, then power amplifier noise compensation accuracy is improved, but computational resource usage and board space increase
Solution Approach 1:
The patent applies universality by designing the receiver path to perform multiple functions: it processes feedback signals during uplink periods for DPD coefficient calculation and receives wireless transmission signals during downlink periods. This multi-functional design eliminates the need for separate specialized hardware paths, reducing device complexity and board space while maintaining the precision required for power amplifier noise compensation through proper signal routing and processing.
Data Source
AI summary
Examples described herein include methods, devices, and systems which may compensate input data for non-linear power amplifier noise to generate compensated input data. In compensating the noise, during an uplink transmission time interval (TTI), a switch path is activated to provide amplified input data to a receiver stage including a coefficient calculator. The coefficient calculator may calculate an error representative of the noise based partly on the input signal to be transmitted and a feedback signal to generate coefficient data associated with the power amplifier noise. The feedback signal is provided, after processing through the receiver, to a coefficient calculator. During an uplink TTI, the amplified input data may also be transmitted as the RF wireless transmission via an RF antenna. During a downlink TTI, the switch path may be deactivated and the receiver stage may receive an additional RF wireless transmission to be processed in the receiver stage.