MU-MIMO Precoder Generation via PMI Correlation Thresholds
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Solution Overview
Problem
Current MU-MIMO systems face suboptimal precoding performance when channel state information (CSI) used for precoding matrices is not orthogonal between UEs and eNodeB, leading to inefficient data transmission.
Innovation Solution
A method for generating optimized precoders by computing correlation values between reported precoding matrix indicators (PMIs) and channel matrices, selecting suitable pairs, and iteratively computing precoders based on postcoders and Lagrange multipliers to achieve joint transmit and receive optimization without requiring orthogonal CSI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If non orthogonal precoding matrices are applied between paired or grouped UEs, then transmission capacity can be maintained, but precoding performance deteriorates due to interference between UEs
Solution Approach 1:
The patent changes the parameter selection approach by computing correlation values between different precoding matrices and selecting matrices based on correlation thresholds rather than assuming orthogonality. This allows the system to adapt to non-orthogonal conditions while maintaining performance through correlation-based selection criteria
Solution Approach 2:
The patent utilizes feedback mechanisms where UEs report preferred precoding matrices (PMIs) based on their channel conditions, and the eNodeB uses this feedback to make informed decisions about which matrices to apply. The system iteratively refines precoder selection based on correlation measurements and threshold comparisons
2Reliability
If orthogonal CSI is required for precoding optimization, then precoding performance improves, but system complexity increases due to additional orthogonality constraints and processing
Solution Approach 1:
The patent extracts the orthogonality requirement from the precoding process by introducing correlation-based selection as an alternative criterion. Instead of mandating orthogonal CSI, the system extracts and uses only the necessary correlation information between precoding matrices to make selection decisions, simplifying the overall system requirements
Solution Approach 2:
The patent applies partial orthogonality checking through correlation threshold comparisons rather than requiring full orthogonality. By using correlation values as a proxy and applying threshold-based selection, the system achieves sufficient performance without the full complexity of enforcing strict orthogonality constraints
Data Source
AI summary
This method of generating precoders is used in optimising transmission capacity between an eNodeB and UEs in a DL MU-MIMO communication system. The method includes the steps of computing correlation values between pairs of precoding matrices (PMs) of the reported precoding matrix indicators (PMIs) (step 40), selecting a PM pair having a minimum correlation value (step 42). If the minimum correlation value is less than a lower threshold Tmin, the method uses a PM corresponding to the received PMI (step 44). If the minimum correlation value is greater than Tmin and less than an upper threshold Tmax, the method includes the steps of computing correlation values of the reported PMI and Channel Matrices (CMs) from a fixed codebook of representative CMs (step 48), selecting a CM pair having a maximum correlation value (step 52), and computing precoders from the selected CM pair (step 54).