MU-MIMO Pre-scheduling for Beamforming Accuracy
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Solution Overview
Problem
In MU-MIMO antenna systems, the accuracy of the beam forming matrix is compromised due to the degradation of sounding signal quality caused by interference from multiple users transmitting sounding signals across the entire frequency band, leading to reduced power allocation and increased interference.
Innovation Solution
A method and apparatus for pre-scheduling that limits the number of users transmitting sounding signals to specific frequency bands, allowing for increased power allocation and reduced interference, thereby improving the accuracy of the beam forming matrix.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If all users transmit sounding signals through the entire frequency band, then channel information can be obtained from all users, but the power allocated to each frequency band decreases and interference increases
Solution Approach 1:
The frequency band is segmented into multiple sub-bands, and users are assigned to transmit sounding signals in specific sub-bands rather than the entire frequency band. This segmentation reduces interference in each sub-band while maintaining comprehensive channel information collection across all users.
Solution Approach 2:
Different users transmit sounding signals in different local frequency regions (sub-bands) according to their channel conditions. This local quality approach allows each user to transmit with higher power in their assigned sub-band, improving signal quality while reducing overall interference.
2Measurement precision
If all users transmit sounding signals across the entire frequency band, then complete channel coverage is achieved, but the quality of the sounding signal is degraded
Solution Approach 1:
The system segments the user population across different frequency sub-bands, limiting the number of users transmitting in each sub-band. This reduces the quantity of simultaneous transmitters in each local region, improving sounding signal quality while maintaining system-wide coverage.
Solution Approach 2:
Not all users transmit sounding signals in all frequency bands simultaneously. Instead, each user transmits in selected sub-bands based on channel conditions and system scheduling, reducing the total number of concurrent transmissions in each frequency region while maintaining overall system performance.
3Productivity
If sounding signals are transmitted by multiple users in the same frequency band, then resource utilization is maximized, but interference from other cells increases
Solution Approach 1:
The frequency band is divided into multiple sub-bands that can be selectively assigned to different user groups. This segmentation allows the system to control the number of users transmitting in each sub-band, reducing inter-cell interference while maintaining efficient resource utilization across the entire frequency spectrum.
Data Source
AI summary
A method and an apparatus for pre-scheduling in a closed-loop multiple user multiple input multiple output (MU-MIMO) antenna system. A base station receives channel information representing a downlink channel condition of each mobile station from mobile stations in a cell, and determines a candidate user group for each of frequency bands included in an entire frequency band, based on the channel information, the candidate user group including mobile stations to which resources can be simultaneously allocated. The base station also instructs a mobile station included in each candidate user group to transmit a sounding signal through a corresponding frequency band. If the sounding signal is received through the corresponding frequency band, the base station performs a scheduling with regard to the mobile station included in each candidate user group.