Adaptive CQI Determination Using Sub-band Deviation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication networks, the delays in Channel Quality Indicator (CQI) reporting lead to outdated CQI reports, resulting in suboptimal performance due to fast fading and interference changes, especially for non-stationary communication nodes, which affects frequency selective scheduling and link adaptation.
Innovation Solution
The method involves obtaining multiple CQI reports at different time instances, estimating channel quality deviations for subbands, and using these deviations to determine updated channel quality indications, allowing for more accurate scheduling and link adaptation by predicting CQI changes based on historical data and neighboring subband trends.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CQI reports are transmitted periodically with standard reporting intervals, then the signaling load is manageable, but the CQI data becomes outdated due to fast fading and interference changes
Solution Approach 1:
The patent applies preliminary action by predicting future CQI values based on historical CQI reports and channel characteristics before actual scheduling decisions are made. The network entity estimates channel quality deviations and generates predicted CQI reports in advance, allowing scheduling algorithms to use more accurate forward-looking CQI data rather than relying solely on outdated periodic reports.
2Measurement precision
If the CQI reporting interval is reduced to improve accuracy, then the CQI data remains more current, but the uplink control signaling load increases
Solution Approach 1:
The patent applies local quality by generating CQI predictions selectively for specific subbands rather than uniformly across the entire bandwidth. The network entity identifies subbands with significant channel quality deviations and generates predicted CQI reports primarily for those subbands, reducing overall signaling volume while maintaining accuracy where it matters most for scheduling decisions.
3Productivity
If frequency selective scheduling is performed using outdated CQI reports, then scheduling decisions can be made with available data, but the scheduling performance deteriorates due to channel changes
Solution Approach 1:
The patent applies feedback by continuously monitoring actual channel conditions and comparing them with predicted CQI values. The network entity uses feedback from channel quality measurements and scheduling outcomes to refine its prediction algorithms, adjusting channel quality deviation estimates and improving the accuracy of future CQI predictions for better scheduling performance.
Data Source
AI summary
The present solution relates to a method in a first communication node (201) for determining an indication of channel quality of a radio channel (205) between the first communication node (201) and a second communication node (203). The first communication node (201) and the second communication node (203) are comprised in a wireless communication network (200). The radio channel (205) comprises a plurality of sub bands. First, at least two channel quality reports are obtained (701) for different time instances. Each channel quality report comprises indications of channel quality of at least two of the plurality of sub bands. Then a channel quality deviation is estimated (702) for at least one of the plurality of sub bands. Further, an indication of a channel quality is determined (703) for at least one of the plurality of sub bands based on the estimated channel quality deviation.