Hybrid Digital-Analog Precoder Pre-Distortion Circuit
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Solution Overview
Problem
In 5G and other multi-antenna systems, power amplifiers face inefficiencies due to non-linear responses at higher amplification levels, leading to increased power consumption, and existing digital pre-distortion methods are not efficiently implementable in hybrid analog/digital precoders used in large antenna arrays.
Innovation Solution
The use of an analog non-linear precoder to insert digital pre-distortion before the power amplifier, reducing the number of digital-to-analog converters required by combining baseband signals and cross products, thereby improving power efficiency in hybrid digital/analog precoding systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digital pre-distortion is implemented in hybrid analog/digital precoders using conventional methods, then power amplifier non-linearity can be compensated, but the number of digital-to-analog converters increases leading to higher power consumption
Solution Approach 1:
The patent combines the digital pre-distortion function with the existing digital precoder by integrating a pre-distortion module that processes baseband signals digitally before they reach the digital-to-analog converters. This merging approach allows power amplifier non-linearity compensation to be achieved without adding separate digital-to-analog converter paths, thereby maintaining lower power consumption while improving output signal quality
2Measurement precision
If more digital-to-analog converters are added to implement pre-distortion in hybrid precoders, then signal accuracy improves, but device complexity and power consumption increase
Solution Approach 1:
The patent applies preliminary digital pre-distortion processing to the baseband signals before they are converted to analog form. By pre-compensating for power amplifier non-linearity in the digital domain using algorithms that model the amplifier characteristics, the system achieves high signal accuracy without requiring additional digital-to-analog converters, thus avoiding increased device complexity
Data Source
AI summary
A 5G base station transmitter at least partially precodes data for beam forming, and generates digital precoded baseband signals. Cross product circuitry coupled to the digital precoder, generates digital cross products of the digital precoded baseband signals. Both the baseband signals and the cross products are put through digital-to-analog converters (DACs), then provided to an analog non-linear precoder. The analog non-linear precoder combines the analog baseband signals, the cross products, with pre-distortion and precoder coefficients to generate a signal that is pre-compensated for power amplifier non-linearity. The pre-compensated signal is amplified by the power amplifier and transmitted via a phased antenna array. The number of extra DACs required for inserting pre-distortion when a hybrid digital/analog precoder is used can be limited to approximatelyNRF(NRF-1)2,where NRF is the number of outputs of the digital precoder. This is significantly fewer than the number of extra DACs used by other methods.