Millimeterwave CQI Feedback for Multi-Beam Interference Estimation
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Solution Overview
Problem
The existing CQI feedback scheme in LTE MU-MIMO systems is inadequate for accurately estimating interference in millimeterwave bands, leading to performance deterioration in multi-user MIMO communications.
Innovation Solution
A method for defining and feeding back a new CQI that considers signal-to-interference plus noise ratio (SINR) across multiple beams, allowing for more precise interference assessment and improved scheduling in multi-antenna communication systems, particularly in the millimeterwave band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the existing LTE CQI feedback scheme is used in millimeterwave MU-MIMO systems, then the system complexity is kept low, but the interference estimation accuracy deteriorates
Solution Approach 1:
The patent changes the parameters of the CQI feedback scheme by introducing a new CQI definition specifically for millimeterwave MU-MIMO systems. This new CQI incorporates multiple beam-specific CQI values and interference measurements, transforming the single-value CQI into a multi-dimensional parameter set that accurately reflects the complex interference environment in millimeterwave bands.
Solution Approach 2:
The patent segments the CQI feedback into multiple beam-specific CQI values instead of using a single aggregate CQI. Each beam's channel quality is measured and reported separately, allowing the base station to understand the interference situation for each individual beam and make more precise scheduling decisions.
2Productivity
If more antennas are used in millimeterwave band to increase the number of simultaneous streams, then the peak user rate is improved, but the interference among streams increases
Solution Approach 1:
The patent implements enhanced feedback mechanisms where terminals report beam-specific CQI values that include interference measurements. This feedback provides the base station with detailed information about the interference environment for each beam, enabling the base station to adjust scheduling decisions, beamforming weights, and power allocation to mitigate interference while maintaining high data rates.
3Duration of action of moving object
If beamforming technology is used to compensate for path attenuation in millimeterwave band, then the transmission distance is extended, but the sensitivity to misalignment and interference increases
Solution Approach 1:
The patent performs preliminary beam alignment and channel quality assessment before data transmission. The terminal measures reference signals from multiple beams and reports beam-specific CQI values in advance, allowing the base station to pre-select the optimal beam and configure appropriate scheduling parameters before actual data transmission begins.
Data Source
AI summary
Provided is a method for feeding back a channel quality indicator (CQI) by a terminal. The terminal receives, from a base station, at least one reference signal through at least one of multiple beams of the base station. The terminal measures a signal-to-interference plus noise ratio (SINR) for the at least one reference signal. The terminal determines a first level corresponding to the measured SINR among levels of a first CQI. In addition, the terminal feeds back the first CQI having the first level to the base station.