Shared Receiver Feedback for Adaptive Transmitter Pre-Distortion
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently transmitting large amounts of data within a given bandwidth while conserving battery power, as efficient amplifiers introduce distortion and require additional hardware for adaptive pre-distortion, increasing cost and chip real estate.
Innovation Solution
A modem with a digital pre-distortion module and shared receivers that generate feedback signals, allowing the digital pre-distortion to be adjusted without a dedicated receiver, using a feedback switch to selectively couple the receivers to the transmitter output and input, enabling adaptive pre-distortion without additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If efficient amplifiers are used to increase battery life, then power consumption is reduced, but distortion and spectral re-growth are introduced
Solution Approach 1:
The patent applies pre-distortion to the transmit signal before it enters the power amplifier. The pre-distortion module intentionally distorts the signal in advance to counteract the distortion that will be introduced by the efficient (non-linear) amplifier, thereby allowing the amplifier to operate efficiently while maintaining signal integrity
Solution Approach 2:
The patent implements a feedback mechanism where a shared receiver captures the amplified transmit signal and provides it back to the pre-distortion module. This feedback loop enables the system to monitor the actual distortion introduced by the amplifier and dynamically adjust the pre-distortion parameters to compensate for it, resolving the contradiction between efficiency and distortion
2Measurement precision
If a dedicated receiver is added for feedback to maintain amplifier model, then distortion compensation is improved, but cost and chip real estate increase prohibitively
Solution Approach 1:
The patent makes the receiver multi-functional by enabling it to serve both its primary function of receiving downlink signals and a secondary function of capturing the uplink transmit signal for feedback. Through a switch that routes the transmit signal to the receiver, the same hardware component performs dual roles, eliminating the need for a dedicated feedback receiver and reducing overall device complexity
Solution Approach 2:
The patent merges the feedback reception function with the existing receiver hardware. Instead of adding separate dedicated feedback reception components, the system combines the feedback path with the shared receiver, integrating multiple functions into a single hardware block thereby reducing cost and chip real estate while maintaining feedback accuracy
Data Source
AI summary
A modem is described. The modem includes a transmitter. The transmitter includes a digital pre-distortion module and a power amplifier. The modem also includes one or more selected shared receivers. The one or more selected shared receivers generate a feedback signal for the digital pre-distortion module. The modem further includes a feedback switch. The feedback switch selectively couples the one or more selected shared receivers to an output of the transmitter.