Uplink Channel Quality Feedback Reduction in Mobile Systems
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Solution Overview
Problem
In wireless mobile communication systems, there is a delay between when channel quality information (CQI) is computed by user equipment and when it is used by the base station for downlink transmissions, leading to potential mismatches due to changing channel conditions, and existing CQI reporting methods place a high load on uplink resources, especially with advanced multi-antenna schemes.
Innovation Solution
The solution involves generating a measure of reliability of a predicted channel estimate and impairment stability, which controls the transmission of channel quality reports, allowing for inhibited transmission during stable and predictable conditions, and using indicators to communicate this to the base station, along with estimating channel quality reports for subsequent transmission operations when actual reports are not received.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If channel quality reports are transmitted frequently to maintain accurate downlink throughput optimization, then link adaptation accuracy is improved, but uplink resource load increases
Solution Approach 1:
The patent applies partial action by transmitting channel quality information selectively rather than continuously. The UE determines whether to transmit CQI based on whether channel conditions have changed beyond a threshold, transmitting only when necessary to maintain adequate link adaptation accuracy while reducing overall uplink resource consumption.
Solution Approach 2:
The patent implements periodic action through discontinuous transmission of channel quality reports. Instead of continuous periodic reporting, the system uses periodic checks of channel conditions with transmission occurring only at intervals when changes exceed the threshold, creating an irregular periodic pattern that reduces uplink load while maintaining necessary information flow.
2Reliability
If channel quality reports are transmitted continuously to account for changing channel conditions, then scheduling accuracy is improved, but uplink resource consumption increases
Solution Approach 1:
The system transmits channel quality information partially - only when channel changes exceed a defined threshold. This partial action maintains scheduling accuracy by ensuring the base station receives updated information when conditions change significantly, while avoiding unnecessary transmissions that would consume uplink resources during stable channel conditions.
Solution Approach 2:
The UE performs self-service by autonomously determining when channel quality information should be transmitted. The UE monitors its own channel conditions, compares changes against thresholds, and makes independent decisions about transmission timing without requiring base station intervention, thereby optimizing the balance between scheduling accuracy and resource consumption.
3Productivity
If channel quality feedback is reduced to save uplink resources, then uplink resource efficiency is improved, but link adaptation performance deteriorates
Solution Approach 1:
The patent applies partial action by transmitting channel quality information selectively rather than continuously. The UE determines whether to transmit CQI based on whether channel conditions have changed beyond a threshold, transmitting only when necessary to maintain adequate link adaptation accuracy while reducing overall uplink resource consumption.
Solution Approach 2:
The system changes the parameter of transmission frequency dynamically based on channel conditions. When channel conditions are stable, transmission frequency is reduced or suspended. When channel conditions change beyond a threshold, transmission frequency increases. This parameter change allows the system to maintain link adaptation performance only when necessary, improving overall uplink resource efficiency.
Data Source
AI summary
Operating a user equipment in a mobile communication system includes generating a measure of reliability of a predicted channel estimate and of impairment stability, wherein the predicted channel estimate is a predicted estimate of a channel between the user equipment and a node of the mobile communications system. Transmission of a channel quality report to the node of the mobile communication system is controlled as a function of the generated measure of reliability of the predicted channel estimate and of impairment stability. Transmission control includes inhibiting transmission of the channel quality report to the node of the mobile communication system for a duration of time corresponding to the measure of reliability of the predicted channel estimate and of impairment stability.