Link Adaptation Feedback Reduction in Wireless Systems
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Solution Overview
Problem
Wideband wireless telecommunications systems face a significant burden on uplink bandwidth due to the high bandwidth required for frequent and accurate channel state information (CSI) and channel quality indicator (CQI) feedback, especially in time and frequency domain systems, which hampers efficient link adaptation and scheduling.
Innovation Solution
Selecting a subset of mobile terminals for simultaneous scheduling and link adaptation, pre-allocating resources, determining transmission weights, and using dedicated pilot signals for feedback information transmission to reduce the amount of feedback information needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If link adaptation and scheduling are implemented in wideband wireless systems, then system capacity and coverage are improved, but uplink bandwidth consumption for feedback signaling increases significantly
Solution Approach 1:
The patent extracts only the essential feedback information (channel quality indicator and interference level) needed for link adaptation, eliminating redundant feedback signaling. Mobile terminals report only these key parameters rather than complete channel state information, significantly reducing uplink feedback bandwidth while maintaining scheduling and link adaptation functionality.
Solution Approach 2:
The patent implements partial feedback reporting where mobile terminals provide only the necessary portion of channel information (CQI and interference levels) rather than complete channel state information. This partial action approach supplies sufficient data for link adaptation decisions without the excessive bandwidth consumption of full CSI reporting.
2Measurement precision
If accurate channel state information feedback is required for transmitter only precoding, then link adaptation accuracy is improved, but feedback signaling complexity and bandwidth increase
Solution Approach 1:
The patent extracts only the critical elements needed for precoding (channel quality indicator and interference covariance matrix) from the complete channel state information. This extraction provides sufficient accuracy for transmitter only precoding while eliminating the complexity of transmitting full channel matrices and covariance information.
Solution Approach 2:
The patent applies local quality by providing high-precision feedback (accurate CQI and interference levels) specifically at the locations where it is most needed for link adaptation decisions, rather than uniformly complex feedback across all dimensions. The feedback focuses on the specific parameters that locally impact transmission quality.
Data Source
AI summary
The invention relates to control of link resources in a wireless telecommunications system, in which instant channel feedback information is transmitted from a mobile terminal in response to receipt of a selection message from a basestation, and the instant channel feedback information is used for real-time resource allocation and adaptation at the basestation. The feedback information includes channel quality information derived from pilot signals and from pre-allocated transmission weights.