Remote Radio Head Predistortion for Efficient Wideband Amplifiers
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Solution Overview
Problem
Current remote radio head units (RRUs) are power inefficient, costly, and inflexible, struggling to support evolving wireless communication standards due to poor DC to RF power conversion and limited software upgradability.
Innovation Solution
The implementation of adaptive digital predistortion techniques, combined with crest factor reduction and power efficiency boosting methods, enables high linearity and efficiency in RF power amplifiers, making RRUs field reconfigurable and capable of supporting multi-frequency bands, multi-modulation schemes, and multi-channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional RF power amplifiers are used in RRUs, then the RRU can provide basic wireless communication functions, but the DC to RF power conversion efficiency is poor and the RRU requires a large mechanical housing
Solution Approach 1:
The patent applies digital predistortion techniques that modify the signal parameters before amplification to compensate for amplifier nonlinearities and inefficiencies. By changing the signal characteristics through digital processing rather than relying on traditional analog amplifier designs, the system achieves better power conversion efficiency while maintaining compact form factor.
Solution Approach 2:
The patent replaces traditional mechanical/analog RF amplifier systems with a digital signal processing approach. Digital predistortion algorithms process the RF signals in the digital domain before conversion, substituting complex analog amplifier circuits with programmable digital processing that achieves comparable or superior performance in a smaller package.
2Adaptability or versatility
If traditional RRU designs are used, then the hardware is fixed and costly, but the system lacks flexibility to support evolving wireless communication standards and multi-frequency bands
Solution Approach 1:
The patent implements dynamically reconfigurable RRU hardware that can adapt its operating characteristics through software control. The system uses programmable signal processing and controllable signal routing to dynamically switch between different wireless standards, frequency bands, and modulation schemes without requiring physical hardware changes.
Solution Approach 2:
The patent creates a universal RRU platform that can perform multiple wireless communication functions through software configuration. A single hardware design supports various wireless standards (GSM, WCDMA, LTE, etc.), multiple frequency bands, and different modulation schemes by loading appropriate software algorithms and configuring signal processing parameters.
3Ease of operation
If traditional RRU systems are deployed, then basic single-standard communication is possible, but the system lacks field reconfigurability and requires extensive hardware upgrades for standard evolution
Solution Approach 1:
The patent replaces physical hardware reconfiguration with software-based configuration. Field reconfigurability is achieved through programmable signal processing and software-controlled signal routing, eliminating the need for mechanical or physical hardware modifications when deploying new standards or features.
Solution Approach 2:
The patent incorporates preliminary software configuration capabilities that allow the RRU to be pre-programmed with multiple wireless standard profiles and frequency band configurations. This preliminary preparation enables rapid field deployment and reconfiguration without requiring complex hardware assembly or modification procedures.
Data Source
AI summary
A remote radio head unit (RRU) system for achieving high efficiency and high linearity in wideband communication systems is disclosed. The present invention is based on the method of adaptive digital predistortion to linearize a power amplifier inside the RRU. The power amplifier characteristics such as variation of linearity and asymmetric distortion of the amplifier output signal are monitored by a wideband feedback path and controlled by the adaptation algorithm in a digital module. Therefore, embodiments of the present invention can compensate for the nonlinearities as well as memory effects of the power amplifier systems and also improve performance, in terms of power added efficiency, adjacent channel leakage ratio and peak-to-average power ratio. The present disclosure enables a power amplifier system to be field reconfigurable and support multi-modulation schemes (modulation agnostic), multi-carriers, multi-frequency bands and multi-channels. As a result, the remote radio head system is particularly suitable for wireless transmission systems, such as base-stations, repeaters, and indoor signal coverage systems.