PUCCH Subband Feedback Signaling with PTI Period Control
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Solution Overview
Problem
There is a need for improved methods and devices in Rel-10 wireless networks to provide feedback information related to Channel Quality Indicator (CQI), Precoder Matrix Index (PMI), and Rank Indicator (RI) that minimize overhead signaling while enhancing feedback granularity.
Innovation Solution
A mobile station transmits feedback reports with a precoder type indication (PTI) value that determines the period of subsequent reports, allowing for rank-dependent codebook subset selection and differentiated feedback information transmission, including wideband and subband feedback, to optimize feedback reporting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback reports transmit detailed subband feedback information (CQI, PMI, RI) for each subband, then feedback granularity is improved, but overhead signaling increases
Solution Approach 1:
The patent segments feedback information into wideband feedback (transmitted periodically) and subband feedback (transmitted selectively). The mobile station determines whether to transmit subband feedback based on channel conditions and configuration, allowing detailed granularity only where needed rather than uniformly across all subbands, thus reducing overall overhead while maintaining precision where required.
Solution Approach 2:
The patent applies different feedback reporting strategies to different subbands based on local channel conditions. Subband feedback is transmitted selectively for subbands experiencing significant channel variations or poor conditions, while subbands with stable good conditions use wideband feedback only. This local adaptation optimizes the balance between granularity and overhead.
2Reliability
If feedback reports are transmitted frequently to maintain up-to-date channel information, then feedback reliability is improved, but signaling overhead increases
Solution Approach 1:
The patent implements periodic wideband feedback transmission at configured intervals, combined with selective subband feedback transmission triggered by specific conditions (e.g., channel quality thresholds, rank changes). This periodic base structure ensures reliability while avoiding continuous full-detailed reporting that would increase overhead unnecessarily.
Solution Approach 2:
The patent transmits partial feedback information (wideband only) under normal conditions and adds subband details only when necessary (e.g., when channel conditions deteriorate or specific triggering events occur). This partial action approach maintains reliability by ensuring periodic feedback while avoiding excessive transmission of complete detailed information in all cases.
3Loss of information
If the mobile station transmits both wideband and subband feedback information in every report, then feedback completeness is improved, but device complexity increases
Solution Approach 1:
The patent makes the feedback reporting structure dynamic and adaptive. The mobile station configures feedback parameters (subband size, reporting frequency, triggering conditions) based on channel conditions, device capabilities, and network requirements. This dynamic configuration allows the system to adjust the balance between completeness and complexity in real-time rather than using a fixed rigid structure.
Solution Approach 2:
The patent establishes wideband feedback transmission as a preliminary base layer that is always maintained. Subband feedback is then added as an optional enhancement layer only when configured and needed. This preliminary action ensures a complete baseline feedback is always available while avoiding the complexity of processing and transmitting full subband details in all cases.
Data Source
AI summary
A mobile station for use in a wireless network. The mobile station transmits feedback reports to a base station of the wireless network. The feedback reports comprise a first feedback report, a second feedback report and a third feedback report. The first feedback report includes a precoder type indication (PTI) value that indicates at least one of a period of the second feedback report and a period of the third feedback report. The PTI value indicates a ratio of the second feedback report period to the third feedback report period. The PTI value also indicates the selected feedback information contained in the second feedback report and the third feedback report.