MU-MIMO Interference Pre-Cancellation for URLLC
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless communication systems face challenges in co-scheduling transmission of mobile broadband and ultra-low latency data blocks using MU-MIMO, leading to interference and performance degradation, particularly for URLLC traffic which requires strict latency and reliability.
Innovation Solution
A method is introduced where a base station determines a reference spatial subspace and selects a user device for mobile broadband data block transmission based on Euclidean distance, projects the precoder matrix to align with this subspace, and co-schedules transmission with URLLC data blocks using shared physical resource blocks, while the URLLC user device projects its decoder matrix to be orthogonal to the reference subspace to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If co-scheduling transmission of mobile broadband data block and ultra low latency data block using MU-MIMO is implemented, then spectral efficiency is improved, but interference between transmissions increases
Solution Approach 1:
The patent projects the precoder matrix from the original signal space to a target plane that is orthogonal to the reference spatial subspace. This dimensional transformation allows the mobile broadband transmission to be confined to a specific subspace, thereby reducing interference in the orthogonal dimensions where ultra low latency transmissions occur, while still utilizing the full MIMO capacity for improved spectral efficiency.
Solution Approach 2:
The patent applies different spatial processing strategies to different user devices based on their service requirements. Mobile broadband users receive transmissions in the reference spatial subspace optimized for their channel conditions, while ultra low latency users receive transmissions in the orthogonal complement subspace. This localized optimization allows each user type to achieve its performance goals without mutual interference.
2Object-affected harmful factors
If precoder matrix projection to target plane is applied, then interference to ultra low latency user device is reduced, but complexity of signal processing increases
Solution Approach 1:
The base station performs the precoder matrix projection to the target plane in advance, before the actual data transmission. By pre-computing the projected precoder matrix that is orthogonal to the reference spatial subspace, the system eliminates interference at the source without requiring complex real-time processing at the user device. The projected precoder matrix is then used for straightforward linear modulation and transmission.
3Object-affected harmful factors
If ultra low latency user device projects decoder matrix to be orthogonal with reference spatial subspace, then interference rejection is improved, but computational load at user device increases
Solution Approach 1:
The ultra low latency user device autonomously projects its decoder matrix to be orthogonal to the reference spatial subspace based on locally available channel state information and the known reference precoder matrix. This self-service approach allows the device to perform interference rejection without requiring additional signaling from the base station or complex joint processing, thereby reducing computational load while maintaining effective interference rejection.
Data Source
AI summary
A technique may include determining, by the ultra low latency user device, a decoder matrix; receiving, by the ultra low latency user device, control information indicating that a scheduled transmission of an ultra low latency data block to the ultra low latency user device is co-scheduled with a transmission of a mobile broadband data block to a mobile broadband user device via a set of shared physical resource blocks using multi-user multiple-input, multiple-output (MU-MIMO); and projecting, by the ultra low latency user device, the decoder matrix of the ultra low latency user device to be substantially orthogonal with a reference spatial subspace in which a precoder matrix for the mobile broadband user device is aligned with the reference spatial subspace, to reduce interference at the ultra low latency user device caused by the transmission of the enhanced mobile broadband data block, when receiving the ultra low latency data block.