SPS Trigger Validation for FDD TTI Bundling Misalignment
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Solution Overview
Problem
Existing wireless communication systems face issues with falsely triggered semi-persistent scheduling (SPS) grants in frequency division duplexing (FDD) traffic associated with transmission time interval (TTI) bundling, leading to misaligned subframes and inefficient resource utilization.
Innovation Solution
A method and apparatus for a user equipment (UE) to detect an SPS trigger, determine its validity based on the alignment of subsequent TTI bundling grants, and adjust the transmission schedule accordingly, either reverting to a previous grant or maintaining the current schedule based on the alignment proportion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If SPS trigger is detected in misaligned subframe, then resource utilization improves through flexible scheduling, but transmission reliability deteriorates due to misalignment with TTI bundling periodicity
Solution Approach 1:
The UE monitors subsequent TTI bundling grants to detect misalignment patterns and provides feedback by determining SPS trigger validity. When misalignment is detected, the UE invalidates the SPS trigger and reverts to the previous transmission schedule, ensuring reliable communication while maintaining flexibility when alignment is proper.
2Reliability
If SPS trigger validity is determined by monitoring multiple TTI bundling grants, then transmission reliability improves through error detection, but device complexity increases due to additional monitoring and determination procedures
Solution Approach 1:
The UE monitors a specific number of subsequent TTI bundling grants (e.g., 2-4 grants) to determine SPS trigger validity, rather than continuously monitoring all future grants. This partial monitoring approach provides sufficient reliability to detect misalignment while limiting the complexity and computational overhead of the detection procedure.
3Reliability
If SPS trigger is invalidated due to misalignment, then transmission reliability improves by correcting errors, but loss of time occurs due to schedule reversion and re-synchronization
Solution Approach 1:
The UE maintains the previous transmission schedule in memory before invalidating the SPS trigger. When misalignment is detected, the UE immediately reverts to the pre-stored schedule without needing to re-synchronize or recalculate timing, thereby minimizing time loss while ensuring reliable communication through rapid correction of the erroneous SPS trigger.
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive first configuration information indicating a transmission time interval (TTI) bundling resource. The UE may receive second configuration information indicating semi-persistent scheduling (SPS) resources. The UE may detect, during a communication session, an SPS trigger for using the SPS resources in a subframe that is misaligned with a periodicity associated with the TTI bundling resource. The UE may determine whether the SPS trigger is valid based at least in part on a number of TTI bundling grants subsequent to the detection of the SPS trigger that are misaligned with the subframe associated with the SPS trigger. Numerous other aspects are provided.