Carrier Aggregation Downlink Grant Validation
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Solution Overview
Problem
In wireless communication systems employing carrier aggregation, the increased number of cells configured leads to higher false detection probabilities of downlink control channels, resulting in erroneous physical uplink control channel transmissions and performance reductions.
Innovation Solution
A method for a user equipment (UE) to determine the validity of downlink grants, allowing only valid grants to initiate physical uplink control channel transmissions, thereby reducing false detection errors and performance losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier aggregation is implemented with multiple cells, then data transfer rate is improved, but false detection probability of downlink control channels increases
Solution Approach 1:
The patent applies preliminary action by checking the Downlink Assignment Index (DAI) value before initiating PUCCH transmission. The UE performs a preliminary validation step to determine whether a detected downlink grant is valid by comparing the DAI value against expected values, preventing erroneous transmissions before they occur. This advance checking mechanism resolves the contradiction by maintaining high productivity through carrier aggregation while improving reliability through pre-transmission validation.
2Productivity
If carrier aggregation is implemented with multiple cells, then system capacity is improved, but erroneous PUCCH transmission increases
Solution Approach 1:
The patent introduces the DAI value as an intermediary element that mediates between the downlink grant reception and PUCCH transmission. The DAI acts as a validation marker that the UE checks before transmitting PUCCH, serving as an intermediary verification step. This intermediary mechanism allows the system to maintain high capacity through multiple cells while filtering out erroneous transmissions through the DAI validation process.
3Productivity
If downlink grant detection sensitivity is increased, then resource allocation efficiency is improved, but false detection rate increases
Solution Approach 1:
The patent implements feedback through the DAI value that provides verification information back to the UE about the validity of detected downlink grants. The DAI acts as a feedback mechanism that confirms whether a detected grant is legitimate or a false detection. This feedback loop allows the system to maintain high detection sensitivity for resource allocation efficiency while using the DAI feedback to identify and reject false detections, thus improving reliability.
Data Source
AI summary
The present method, for a terminal carrying out carrier aggregation in a wireless communication system, comprises the steps of: receiving, from a base station, at least one downlink grant; determining whether or not the at least one downlink grant corresponds to a valid downlink grant; and on the basis of the determination, transmitting a physical uplink control channel (PUCCH), wherein the PUCCH transmission step, on the basis of the determination, comprises the steps of: if a downlink grant included in the at least one downlink grant is a valid down grant, then transmitting a PUCCH associated with the valid downlink grant; and if a downlink grant included in the at least one downlink grant is not a valid down grant.