Feed-Forward PA Offline Tuning Using Simulated Carrier Signals
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Solution Overview
Problem
Feed-Forward Power Amplifiers (PAs) struggle to maintain accurate internal tuning in the absence of input carriers, which is critical for Land Mobile Radio (LMR) applications due to dynamic transmitter carrier conditions, leading to inefficiencies and power consumption issues.
Innovation Solution
A feed-forward PA with a simulated carrier generator and processor that enables tuning of the PA even when no actual carriers are present, using advanced methods for rapid convergence and minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional Feed-Forward PAs are used in LMR applications, then power efficiency can be improved during carrier transmission, but tuning accuracy deteriorates during periods without carriers
Solution Approach 1:
The system performs tuning operations in advance during periods when carriers are present, storing the tuned parameters for later use. This preliminary tuning action ensures that when carriers are absent, the PA maintains accurate tuning settings without requiring continuous carrier presence, thus resolving the contradiction between power efficiency and tuning accuracy.
Solution Approach 2:
The system creates a model or representation of the carrier signal characteristics and uses this copied information to maintain tuning accuracy during periods when actual carriers are absent. By working with a replicated signal model rather than requiring the actual carrier, the system preserves tuning precision while allowing carrier-free periods for power savings.
2Measurement precision
If Feed-Forward PAs require continuous carrier presence for tuning, then tuning accuracy is maintained, but adaptability to LMR dynamic conditions deteriorates
Solution Approach 1:
The system dynamically adapts its operation mode based on carrier presence detection. When carriers are present, it performs tuning operations; when carriers are absent, it maintains previously tuned parameters. This dynamic behavior allows the PA to maintain tuning accuracy while adapting to the dynamic carrier conditions characteristic of LMR applications.
Solution Approach 2:
The system uses its own internal resources and stored tuning information to maintain accuracy during carrier-absent periods, rather than requiring external carriers. This self-service capability allows the PA to sustain tuning precision independently of continuous carrier presence, thereby adapting to dynamic LMR conditions.
3Device complexity
If tuning is performed only when carriers are present, then device complexity remains low, but productivity during carrier-absent periods deteriorates
Solution Approach 1:
The system performs tuning operations in advance during carrier-present periods, preparing the PA for future transmission tasks. This preliminary action ensures that when carriers become available again after absent periods, the PA is already tuned and ready for immediate productive operation, thus improving transmission readiness without adding significant complexity.
Data Source
AI summary
A method and base station transmitter for providing offline tuning of a base station transmitter. The base station transmitter includes a feed-forward power amplifier comprising a Radio Frequency (RF) input and an RF output. The base station transmitter also includes a simulated carrier generator operatively coupled to the feed-forward power amplifier prior to the carrier cancellation loop. The simulated carrier generator provides a simulated carrier signal including one or more individual carrier frequencies to the RF input. The base station transmitter also includes a processor that is operatively coupled to the feed-forward power amplifier and the simulated carrier generator. The processor performs tuning of a carrier cancellation loop using the simulated carrier signal when the processor determines that a carrier signal is not present.