Transmitter Beamforming Weights via Random Phase Power Feedback
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Solution Overview
Problem
Conventional beamforming schemes for microwave power transmission require complex hardware and result in high energy consumption and slow beamforming speeds, particularly in time reversal and power-based control methods.
Innovation Solution
A method that estimates channel gain based on received power measurements by a receiver, using a transmitter with antennas configured to send microwaves with random phases, an RF receiver to measure power, and a controller to determine beamforming weights for optimal power transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If time reversal scheme is used for beamforming, then beamforming capability is achieved, but hardware complexity increases significantly
Solution Approach 1:
The patent extracts and eliminates the complex hardware components (phase detectors for each antenna, active circuit elements at receiver) while retaining the essential beamforming function through a simplified architecture where only the transmitter performs channel estimation and beamforming operations
Solution Approach 2:
The transmitter is designed to perform multiple functions: it generates microwave signals, estimates channel conditions, calculates beamforming weights, and transmits power-efficiently all in one device, eliminating the need for separate complex receiver-side beamforming hardware
2Power
If active circuit elements are included at receiver for microwave transmission, then power transmission capability is improved, but energy consumption increases significantly
Solution Approach 1:
The transmitter performs self-estimation of channel conditions and self-calculation of beamforming weights using received power measurements, eliminating the need for the receiver to actively participate in beamforming operations and thus reducing receiver energy consumption
Solution Approach 2:
Instead of having the receiver actively measure and feedback phase information (conventional approach), the patent inverts the approach by having the receiver only measure power and the transmitter perform all complex processing based on this simple measurement
3Ease of operation
If conventional power-based beamforming control is used, then beamforming is achieved, but beamforming speed becomes very slow
Solution Approach 1:
The transmitter performs preliminary channel estimation and beamforming weight calculation based on received power measurements before actual power transmission, enabling fast adaptation to channel changes without waiting for iterative feedback loops
Solution Approach 2:
The system uses feedback from the receiver's power measurements to continuously update beamforming weights at the transmitter, creating a closed-loop system that adapts quickly to channel variations while maintaining simple receiver hardware
Data Source
AI summary
Disclosed is a beamforming method for microwave power transmission. The beamforming method includes sending, by a transmitter, microwaves to each training slot based on a random phase through antennas, receiving from a receiver, by the transmitter, a power measurement value for each of the training slots, estimating, by the transmitter, a channel using the received power measurement value, and determining, by the transmitter, beamforming weight based on information about the estimated channel.