j-MMSE Precoder Generation Using PMI Feedback in DL CoMP
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current precoding methods in Downlink Coordinated Multi-Point (DL CoMP) systems are not optimal and require channel state information (CSI) for generating precoders, which can be complex and inefficient.
Innovation Solution
The method generates Minimum Mean Squared Error (MMSE) precoders, referred to as j-MMSE precoders, using only the Precoder Matrix Indicator (PMI) fed back by User Equipments (UEs), eliminating the need for channel knowledge and applicable to both coherent and non-coherent precoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current precoding methods use channel state information (CSI) to generate precoders, then precoding accuracy can be improved, but system complexity and computational overhead increase
Solution Approach 1:
The patent extracts only the essential PMI information from the complete CSI, discarding the more complex channel matrix details. By using only PMI for precoder generation, the system achieves adequate precoding accuracy while significantly reducing the computational burden and system complexity associated with processing full CSI.
Solution Approach 2:
The patent employs a simplified precoder generation method that uses lightweight PMI indicators instead of heavy CSI data. This approach uses computationally inexpensive operations that can be performed quickly, replacing the more resource-intensive CSI-based precoding while maintaining acceptable performance.
2Reliability
If channel state information is used for precoder generation, then transmission performance can be improved, but feedback overhead and processing time increase
Solution Approach 1:
The patent extracts only the critical PMI component from the full CSI feedback, eliminating the need to process and transmit redundant channel information. This reduction in feedback data decreases overhead and processing time while retaining the essential information needed for effective precoding.
Solution Approach 2:
The patent uses a partial approach by utilizing only PMI rather than complete CSI for precoder generation. This partial information is sufficient to achieve good transmission performance while avoiding the excessive feedback overhead and processing time associated with using full CSI.
3Manufacturing precision
If complete channel knowledge is required for precoding, then precoding optimality can be improved, but implementation complexity and resource requirements increase
Solution Approach 1:
The patent replaces the expensive and complex requirement for complete channel knowledge with inexpensive PMI indicators. The simplified precoder generation using PMI requires minimal computational resources and can be implemented more easily in practical systems while achieving satisfactory precoding optimality.
Solution Approach 2:
The patent extracts the essential directional information from the channel state represented by PMI, discarding the more complex complete channel knowledge requirement. This extraction approach maintains adequate precoding optimality by focusing on the most critical information while dramatically reducing implementation complexity.
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
There is provided generating precoders for joint transmission (JT) in a downlink coordinated multi-point transmission/reception (DL CoMP) wireless communications system. The system includes a plurality of transmission points (TPs) operable to communicate with a plurality of user equipments (UEs). Each UE has one of the TPs as its serving TP. The method includes transmitting channel state information (CSI) from each UE to its serving TP, wherein the transmitted CSI includes precoder matrix indicators (PMI), and using the PMI to generate precoders for transmission of data from the plurality of TPs to the plurality of UEs.