PUCCH Subband Feedback Signaling for Wireless Overhead Reduction
Find Innovative SolutionsGenerate Solutions
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 periodicity and payload efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback reports transmit detailed subband feedback information, then feedback granularity is improved, but overhead signaling increases
Solution Approach 1:
The patent segments feedback information into wideband feedback and subband feedback components. Wideband feedback provides coarse-grained channel quality information across the entire bandwidth, while subband feedback provides fine-grained information for specific frequency subbands. This segmentation allows the system to achieve high feedback granularity when needed while reducing overhead by transmitting only wideband feedback when channel conditions are relatively uniform.
Solution Approach 2:
The patent implements dynamic feedback reporting where the mobile station adapts the feedback granularity and periodicity based on channel conditions, mobility state, and traffic requirements. The feedback mechanism transitions between wideband-only reporting (low overhead) and subband-inclusive reporting (high granularity) dynamically, allowing the system to optimize the trade-off between overhead and granularity in real-time based on actual network conditions.
2Speed
If feedback reports are transmitted frequently, then feedback timeliness is improved, but overhead signaling increases
Solution Approach 1:
The patent implements periodic feedback reporting with configurable periods for wideband feedback and subband feedback. Wideband feedback is reported more frequently with shorter periodicity to provide timely channel quality updates, while subband feedback is reported less frequently with longer periodicity to reduce overhead. This multi-periodic approach allows the system to maintain feedback timeliness for scheduling decisions while minimizing overall signaling overhead.
3Measurement precision
If codebook size is increased for PMI feedback, then precoder selection accuracy is improved, but feedback payload size increases
Solution Approach 1:
The patent applies different codebook sizes and precoder selection accuracies to different feedback scenarios. For wideband feedback, a smaller codebook is used since the precision requirement is lower for overall channel quality assessment. For subband feedback where frequency-selective precoding is beneficial, a larger codebook provides higher precoder selection accuracy. This local differentiation of quality requirements optimizes the balance between payload size and selection accuracy.
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.