Two-Stage DCI Collision Handling in Wireless Systems
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Solution Overview
Problem
Two-stage downlink control information (DCI) in wireless communication systems is more vulnerable to physical downlink control channel (PDCCH) dropping, leading to increased PDCCH dropping rates and degraded performance due to collisions with measurement gaps or cross-link interference measurement occasions, which results in incomplete scheduling information being provided to user equipment (UE).
Innovation Solution
Implementing collision handling techniques such as prioritization, fallback to single-stage DCI, or shifting of first-stage DCI to mitigate collisions, ensuring that both first-stage and second-stage DCI are successfully received by the UE, thereby reducing the likelihood of scheduling information being dropped.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two-stage DCI is used to provide scheduling information, then the scheduling capability is enhanced, but the vulnerability to PDCCH dropping increases
Solution Approach 1:
The DCI is divided into two stages: first-stage DCI transmitted via PDCCH for initial scheduling information, and second-stage DCI transmitted via PDSCH for complete scheduling details. This segmentation allows the system to maintain enhanced scheduling capability while mitigating PDCCH dropping impact, as the more robust PDSCH carries the critical second-stage information.
Solution Approach 2:
The patent implements collision detection mechanisms that identify potential PDCCH dropping scenarios in advance (e.g., when PDCCH overlaps with measurement gaps or CLI measurement occasions). Upon detecting such collisions, the system proactively applies collision handling techniques including prioritization rules, fallback to single-stage DCI, or shifting the first-stage DCI timing, thereby cushioning against the negative effects before they fully manifest.
2Reliability
If collision handling techniques are implemented, then the PDCCH dropping rate is reduced, but the system complexity increases
Solution Approach 1:
The patent modifies key parameters of the DCI transmission process: changing the timing of first-stage DCI transmission (shifting), altering the transmission stage (fallback to single-stage), or adjusting priority levels. These parameter changes provide flexible collision handling mechanisms that reduce PDCCH dropping without requiring fundamentally complex system architecture changes.
3Productivity
If prioritization of two-stage DCI is applied, then the scheduling information delivery is improved, but the collision handling complexity increases
Solution Approach 1:
The patent establishes predetermined prioritization rules and collision handling procedures that are configured in advance. When a collision is detected, the UE automatically applies these pre-defined rules (such as prioritizing first-stage DCI over certain uplink transmissions or favoring specific search space sets) without requiring complex real-time decision-making, thereby improving scheduling information delivery while keeping implementation complexity manageable.
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may detect a collision between one or more of a first-stage downlink control information (DCI) or a second-stage DCI, of a two-stage DCI, and a symbol in which a physical downlink control channel (PDCCH) is not monitored by the UE. The UE may perform a collision handling for the two-stage DCI based at least in part on the collision, wherein the collision handling is based at least in part on one of: a prioritization of the two-stage DCI, a fallback to a single-stage DCI, or a shift of the first-stage DCI. Numerous other aspects are described.