CQI Report Request Based on BLER Thresholds
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Solution Overview
Problem
Current methods for determining when Channel Quality Indication (CQI) reports are transmitted in LTE networks are inefficient, leading to performance loss due to unclear timing for CQI report requests, resulting in unnecessary transmissions and resource wastage.
Innovation Solution
Request CQI reports based on measured Block Error Rate (BLER) thresholds, adjusting the threshold value according to the network's channel knowledge and available resources to optimize uplink grant signaling and resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CQI reports are transmitted frequently to improve scheduling accuracy, then scheduling information accuracy is improved, but uplink resource consumption increases
Solution Approach 1:
The patent changes the parameter of CQI report transmission timing from fixed periodic intervals to dynamic intervals based on BLER threshold comparisons. When BLER exceeds the threshold, CQI reports are triggered; otherwise, transmissions are suppressed. This parameter change optimizes the balance between scheduling accuracy and resource consumption by adapting transmission frequency to actual channel conditions.
Solution Approach 2:
The patent implements a feedback mechanism where the eNodeB monitors BLER and compares it against a threshold, then provides feedback by triggering or suppressing CQI report transmissions accordingly. This closed-loop feedback system ensures CQI reports are transmitted only when channel conditions deteriorate beyond acceptable levels, improving scheduling accuracy while minimizing unnecessary uplink resource usage.
2Reliability
If CQI reports are transmitted on physical control channel, then transmission reliability is improved, but available bit capacity is limited
Solution Approach 1:
The patent applies partial action by selectively transmitting CQI reports only when BLER exceeds a predefined threshold, rather than transmitting continuously. This partial transmission approach ensures reliable delivery of critical channel quality information when needed, while conserving the limited bit capacity of the physical control channel by suppressing redundant transmissions during good channel conditions.
3Productivity
If uplink grant bit is used to request CQI reports, then signaling efficiency is improved, but grant signaling overhead increases
Solution Approach 1:
The patent extracts the CQI report request function from the regular uplink grant signaling by using a specific bit in the uplink grant to indicate CQI reporting requirements. This extraction allows the system to efficiently request CQI reports only when BLER conditions warrant it, improving signaling efficiency while minimizing the overhead associated with grant signaling by avoiding requests during stable channel conditions.
Data Source
AI summary
In a method and a device for requesting Channel Quality Indication (CQI) reports from a mobile station of a cellular radio system, the CQI reports are requested in response to a measured Block Error Rate (BLER) of transmissions from the mobile station. In accordance with one embodiment of the present invention a CQI report is requested if the BLER of the mobile station is above a predetermined threshold value C. The threshold value C can be set to a value related to the BLER target. In particular the value C can be set to the same value or as a value close the BLER that is targeted to try to adapt the CQI report request to how well the base station knows the channel. It can also be set higher or lower to also consider how much CQI reporting the base station estimates can be afforded when it comes to uplink resources and uplink grant signaling in the downlink.