Sub-Band Eigen Precoding for Intermediate-SNR Multi-User MIMO
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current precoding techniques for 5G NR systems are inadequate for UEs operating at intermediate uplink signal-to-noise ratios (SNRs), leading to suboptimal performance in multi-user MIMO transmission.
Innovation Solution
An adaptive sub-band eigen precoding scheme is employed for UEs with intermediate SRS SNRs, using wideband channel computations and eigen vector analysis to improve precoding performance by segregating users into different SNR categories and applying specific precoding methods for each category.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional precoding techniques are used for all UEs, then device complexity is reduced, but precoding performance deteriorates for UEs with intermediate SRS SNRs
Solution Approach 1:
The patent segments UEs into three distinct categories based on their SRS SNR values: high SNR group (≥ second threshold), intermediate SNR group (between thresholds), and low SNR group (< first threshold). Each segment receives a tailored precoding technique, with the intermediate group specifically receiving adaptive sub-band eigen precoding that combines sub-band eigen decomposition with wideband channel computations, while high and low groups receive different treatments. This segmentation resolves the contradiction by applying complexity only where needed to improve performance for intermediate SNR UEs.
Solution Approach 2:
The patent implements dynamic precoding adaptation where the base station determines the appropriate precoding technique based on real-time SRS SNR measurements. The system dynamically switches between different precoding approaches (e.g., sub-band eigen precoding for intermediate SNR, other techniques for high/low SNR) based on each UE's current channel conditions. This dynamic adaptation allows the system to optimize performance for intermediate SNR UEs without permanently increasing complexity for all UEs.
2Reliability
If wideband channel computations are applied to all UEs, then precoding performance improves for intermediate SNR UEs, but computational complexity increases for the base station
Solution Approach 1:
The patent applies local quality by providing different levels of computational complexity to different UE groups based on their SNR characteristics. Only intermediate SNR UEs receive the computationally intensive wideband channel computations and sub-band eigen decomposition. High SNR UEs receive simpler processing leveraging their favorable channel conditions, while low SNR UEs receive processing optimized for their conditions. This localized application of complexity improves performance for the target group without unnecessarily increasing overall system computational burden.
3Reliability
If UE classification into SNR categories is implemented, then precoding performance improves, but measurement and detection difficulty increases
Solution Approach 1:
The patent employs feedback mechanisms where UEs transmit SRS signals and the base station measures their SNR values to determine appropriate precoding techniques. The base station uses this feedback information (SRS SNR measurements) to classify UEs into the appropriate groups and apply corresponding precoding methods. This feedback approach makes the measurement process practical and integrated into the existing communication protocol, avoiding excessive measurement complexity while enabling performance optimization.
Data Source
AI summary
When determining precoding for UEs classified as falling within an intermediate range of uplink signal-to-noise ratio, for which precoding performance is improvable by wideband channel computations of eigen vectors for a channel representation or signal-to-leakage-and-noise ratio (SLNR), the precoding scheme is adapted based at least in part on how the UE is classified. For multiple user operation with other UEs, the precoding scheme orthogonalizes precoder subspaces of each subset of UEs by zero forcing precoding. The precoding scheme for the intermediate range UEs may be an adaptive sub-band eigen precoding scheme that reduces interference caused by a transmission of the UE with reception by other UEs. The precoding scheme for the intermediate range UEs may alternatively optimize SLNR for transmission of the UE relative to transmissions other UEs.