Digital hybrid mode power amplifier system

Abstract

A RF-digital hybrid mode power amplifier 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 in the RF domain. The power amplifier characteristics such as variation of linearity and asymmetric distortion of the amplifier output signal are monitored by the narrowband feedback path and controlled by the adaptation algorithm in a digital module. Therefore, the present invention could compensate the nonlinearities as well as memory effects of the power amplifier systems and also improve performances, 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 and multi-channels. As a result, the digital hybrid mode power amplifier system is particularly suitable for wireless transmission systems, such as base-stations, repeaters, and indoor signal coverage systems, where baseband I-Q signal information is not readily available.

Description

[0001] Cross References to Related Applications [0002] This is a continuation-in-part of US Patent Application S.N.12 / 021,241, filed January 28, 2008, entitled "Power AmplifierTime-Delay Invariant Predistortion Methods and Apparatus," which was subsequently filed April 30, 2007 Continuation-in-Part of U.S. Patent Application S.N.11 / 799,239, entitled "High Efficiency Linearization Power Amplifier For Wireless Communication," which in turn was filed on October 27, 2005, and entitled "System and Method for Digital Memorized Predistortion for Wireless Communication" 11 / 262,079 of U.S. Patent Application S.N. 11 / 262,079, which is a continuation of U.S. Patent Application S.N. 10 / 137,556 entitled "System and Method for Digital Memorized Predistortion for Wireless Communication," now U.S. Patent No. 6,985,704, all These patent applications or patents are hereby incorporated by reference. This application claims priority to US Patent Application S.N. 11 / 961,969, filed December 20, 2...

AI Technical Summary

Problems solved by technology

However, conventional DSP-based PD schemes have the following problems: changes in the linearity of the amplifier due to environmental changes such as temperature, and asymmetric distortion of the output signal of the PA due to memory effects

Practical implementation of this embedding presents challenges as it is often inconvenient or impossible to modify the baseband architecture of an existing base station or base station design

Once a PD scheme is established for a specific base station design, it is often not reconfigurable and therefore cannot be upgraded for future changes in standards or modulation

Also, because traditional PD methods require a baseband I-Q signal source to work, they cannot be applied in some RF systems that do not have any baseband I-Q signal source, such as repeaters and indoor signal coverage subsystems

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