OTA DPD Training for CV2X Groupcast PA Linearity
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Solution Overview
Problem
Current power amplifier (PA) non-linearity correction methods in device-to-device (D2D) wireless communication systems face challenges in efficiently addressing PA non-linearity, particularly in groupcast D2D communication modes, where multiple TX stations need to be trained by multiple RX stations, often requiring high control signaling and overhead.
Innovation Solution
The implementation of over-the-air (OTA) digital pre-distortion (DPD) training for D2D communication systems, where UEs exchange capabilities and request assistance for training DPD coefficients, allowing for PA non-linearity correction without expensive feedback links, using pilot signals and feedback messages to calculate and apply DPD parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional PA non-linearity correction methods are used in groupcast D2D communication, then multiple TX stations can be trained by multiple RX stations, but high control signaling overhead is required
Solution Approach 1:
The patent extracts and removes the expensive feedback links from the traditional DPD training architecture. Instead of requiring multiple RX stations to send feedback messages to multiple TX stations, the system uses one-way pilot signal transmission from TX to RX, with RX stations independently calculating DPD parameters and providing feedback only to their respective TX stations. This extraction of unnecessary feedback links directly reduces control signaling overhead while maintaining correction accuracy.
Solution Approach 2:
The patent segments the groupcast D2D communication into unicast relationships between individual TX-RX pairs. Each TX station trains its DPD coefficients using pilot signals sent to specific RX stations, and each RX station independently provides feedback to its corresponding TX station. This segmentation transforms a complex multi-station training problem into multiple simpler unicast training problems, reducing overall control signaling requirements.
2Reliability
If DPD training is implemented in D2D communication systems, then PA non-linearity correction is achieved, but control signaling and overhead increase
Solution Approach 1:
The patent removes the complex feedback link architecture from traditional DPD training systems. Instead of requiring bidirectional communication and coordinated feedback between multiple TX and RX stations, the system extracts only the essential one-way pilot signal transmission and independent local feedback, dramatically simplifying control signaling while preserving correction functionality.
Solution Approach 2:
Each RX station independently calculates DPD parameters based on received pilot signals and provides feedback to its corresponding TX station without requiring coordination with other stations. This self-service approach eliminates the need for complex centralized control and coordination mechanisms, reducing device complexity while achieving effective non-linearity correction.
3Reliability
If power back-off is applied to address PA non-linearity, then signal quality is maintained, but PA efficiency decreases
Solution Approach 1:
The patent changes the approach from power control (adjusting transmit power levels) to parameter correction (adjusting DPD coefficients). By modifying the DPD parameters based on feedback from RX stations, the system corrects non-linear distortions without reducing transmit power, thereby maintaining both signal quality and PA efficiency. This parameter-based correction eliminates the need for power back-off.
Data Source
AI summary
A first UE may transmit, to a second subset of one or more second UEs, one or more pilot signals associated with DPD training. The first UE may receive, from a third subset of the one or more second UEs, one or more feedback messages associated with DPD training. The one or more feedback messages may be based on the one or more pilot signals. Each second UE in the third subset of the one or more second UEs may correspond to one of the one or more feedback messages. The second UE may calculate one or more DPD parameters based on the one or more feedback messages. The second UE may transmit a first signal based on the calculated one or more DPD parameters.