Partial PMI Feedback for X-MIMO Search Complexity
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Solution Overview
Problem
In 6G communication systems, the increasing number of antenna ports in X-MIMO technology leads to a higher search complexity for the UE and an increased number of bits required for PMI index feedback, resulting in higher uplink control information (UCI) overhead.
Innovation Solution
The method involves dividing the PMI into groups and limiting the reporting of PMI candidate groups, which reduces the search complexity for the UE and decreases the number of bits required for PMI index feedback, thereby reducing UCI overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of antenna ports is increased in X-MIMO technology, then the spectral efficiency and network performance are improved, but the search complexity for the UE and the number of bits required for PMI index feedback increase
Solution Approach 1:
The patent divides the PMI reporting into two parts: a first PMI indicating a beam group (coarse-level selection) and a second PMI indicating a specific beam within the group (fine-level selection). This segmentation reduces the search complexity by breaking down the large search space into smaller, more manageable subsets, while still maintaining the ability to support a large number of antenna ports for high spectral efficiency.
2Productivity
If the number of antenna ports is increased in X-MIMO technology, then the spectral efficiency and network performance are improved, but the number of bits required for PMI index feedback increases
Solution Approach 1:
The PMI feedback is segmented into two separate indicators: first PMI for beam group selection and second PMI for specific beam selection. This segmentation allows the total feedback bits to be distributed across different reporting mechanisms (e.g., first PMI in downlink grant, second PMI in uplink control information), thereby managing the UCI overhead more effectively while supporting large antenna configurations.
Solution Approach 2:
The patent applies partial reporting by only requiring the UE to feedback the second PMI (specific beam selection) when necessary, while the first PMI (beam group selection) can be inferred or reported with fewer bits. This partial action approach reduces the immediate UCI overhead while still providing sufficient information for effective precoding.
Data Source
AI summary
The present disclosure relates to a 5G communication system or a 6G communication system for supporting higher data rates beyond a 4G communication system such as LTE. A method by a base station comprises: determining a number of first dimensional beam groups and a number of second dimensional beam groups for reporting at least one PMI-related parameter for a plurality of two-dimensional beams; transmitting a RRC configuration message including information about the number of the first dimensional beam groups and the number of the second dimensional beam groups; and receiving reporting of the PMI-related parameter based on the RRC configuration message.