User Terminal Beamforming Control via Transmitter Receiver Characteristic Feedback
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Solution Overview
Problem
In future radio communication systems like 5G, forming optimal transmitting beams is challenging due to differences in frequency characteristics between the transmitter and receiver, leading to inadequate beam formation, decreased throughput, and signal quality issues, especially at high carrier frequencies.
Innovation Solution
A user terminal transmits information about its transmitter/receiver characteristics to the base station, allowing the base station to determine whether beams should be formed based on downlink or uplink channel information, enabling the acquisition of necessary channel information for proper beamforming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If beamforming is performed using downlink channel information, then beamforming can be simplified, but throughput and signal quality decrease when transmitter and receiver have different frequency characteristics
Solution Approach 1:
The patent introduces an intermediary mechanism where the receiver measures uplink channel information and feeds it back to the transmitter. This feedback loop acts as a mediator that bridges the frequency characteristic differences between transmitter and receiver, enabling accurate beamforming without requiring direct downlink channel measurement at the transmitter side.
Solution Approach 2:
The patent implements a feedback mechanism where the receiver measures the uplink channel using reference signals, determines the appropriate beamforming matrix based on measured channel characteristics, and feeds back this information to the transmitter. This feedback enables the transmitter to adapt its beamforming strategy to actual channel conditions, resolving the contradiction between simplified beamforming and maintained throughput.
2Ease of operation
If beamforming is performed using downlink channel information, then implementation is simpler, but signal quality deteriorates due to frequency characteristic mismatches
Solution Approach 1:
The patent inverts the traditional beamforming approach by having the receiver (rather than the transmitter) perform the channel measurement and beamforming matrix determination. The receiver measures the uplink channel, calculates the beamforming parameters, and feeds them back to the transmitter for implementation. This inversion allows accurate channel characterization while maintaining implementation feasibility.
Solution Approach 2:
The feedback mechanism serves as an intermediary that transfers accurate channel information from the receiver to the transmitter, enabling reliable beamforming without requiring the transmitter to directly measure the downlink channel, thus avoiding frequency characteristic mismatches.
3Reliability
If uplink channel information is used for beamforming, then accurate beamforming is achieved, but system complexity increases
Solution Approach 1:
The patent applies self-service by having the receiver perform the channel measurement and beamforming matrix determination using its own received reference signals. The receiver utilizes its own measurement capabilities and processing resources to generate the beamforming parameters, which are then fed back to the transmitter. This self-service approach achieves accurate beamforming while distributing the computational burden.
Solution Approach 2:
The feedback mechanism efficiently transmits the computed beamforming parameters from the receiver to the transmitter, enabling accurate beamforming without requiring complex coordinated measurements at both ends. The feedback loop streamlines the process by centralizing the measurement and computation functions at the receiver side.
Data Source
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AI summary
The present invention is designed to suitably reduce the decrease of throughput when communication is carried out using beamforming. A user terminal, according to one aspect of the present invention, has a control section that controls formation of a beam for use in transmitting an uplink signal, and a transmission section that transmits information about a characteristic of a transmitter/receiver, and, after the information about the characteristic of the transmitter/receiver is transmitted, the control section determines whether the beam is formed based on downlink channel information or uplink channel information.