Eigenmode Selection Precoding for Multiuser MIMO Interference
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Solution Overview
Problem
Current precoding methods in multiuser wireless communication systems suffer from a performance gap due to interference between spatial streams, limiting transmission capacity in SDMA systems.
Innovation Solution
The method involves generating an equivalent channel matrix using eigenvectors and eigenvalues, computing an intermediate matrix, and creating a precoding matrix based on this, which is then used to transmit a precoded signal, employing eigenmode selection and minimum mean square error (MMSE) processing to reduce interference and increase capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional precoding methods are used in multiuser wireless communication systems, then the system can maintain simplicity in implementation, but transmission capacity is limited due to interference between spatial streams
Solution Approach 1:
The patent segments the precoding process into distinct stages: eigenmode selection at user terminals, formation of equivalent channel matrix at access point, computation of intermediate matrix, and generation of precoding matrix. This segmentation allows complex interference management to be broken down into manageable steps, improving transmission capacity while maintaining implementable complexity levels.
Solution Approach 2:
The patent applies preliminary action by having user terminals select and feedback eigenmodes before the access point generates the final precoding matrix. This preliminary eigenmode selection and equivalent channel matrix formation enables the access point to pre-compute optimal precoding weights, reducing real-time computational complexity while maximizing transmission capacity through interference reduction.
2Productivity
If spatial streams are transmitted simultaneously to multiple user terminals, then data throughput increases, but interference between user terminals worsens
Solution Approach 1:
The patent converts the harmful interference between spatial streams into a beneficial effect by using MMSE processing to compute precoding weights that explicitly account for interference. Instead of avoiding interference, the system leverages channel state information to design precoding matrices that transform harmful interference patterns into manageable signal components, enabling simultaneous high throughput for multiple users with reduced inter-user interference.
Solution Approach 2:
The patent changes key parameters including the precoding matrix weights, equivalent channel matrix dimensions, and MMSE processing parameters to optimize the balance between data throughput and interference reduction. By dynamically adjusting these parameters based on channel conditions and user requirements, the system achieves high throughput while maintaining low inter-user interference levels.
Data Source
AI summary
The present disclosure proposes a method for precoding of transmission signal at an access point of a multiuse system based on eigenmode selection and minimum mean square error (MMSE) processing. The most reliable eigenmodes of every multiple-input multiple-output (MIMO) channel in the system can be selected at each user terminal and corresponding eigenvalues and eigenvectors can be fed back to the access point. The linear MMSE precoding (beamforming) applied at the access point based on the selected eigenmodes may provide an improved transmission capacity performance.