PUCCH Repetition Mapping via PDCCH Aggregation Levels
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently determining control channel repetition factors for uplink control messages, leading to suboptimal performance in multiple-access systems like LTE and 5G networks.
Innovation Solution
A base station implicitly indicates a physical uplink control channel (PUCCH) repetition factor by selecting an aggregation level for the preceding physical downlink control channel (PDCCH), with the UE using the indicated correspondence for PUCCH transmissions until a new factor is signaled or a timer expires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a base station uses explicit signaling to indicate PUCCH repetition factors, then the reliability of uplink control message transmission is improved, but the signaling overhead and device complexity increase
Solution Approach 1:
The UE autonomously determines the PUCCH repetition factor by mapping the aggregation level of the received PDCCH to a corresponding repetition factor based on pre-configured correspondence relationships. This self-determination mechanism eliminates the need for explicit base station signaling, reducing signaling overhead while maintaining reliable transmission through the structured mapping between aggregation levels and repetition factors.
Solution Approach 2:
The patent transforms the indication mechanism from explicit signaling to implicit parameter mapping. The aggregation level parameter of the PDCCH is directly mapped to the PUCCH repetition factor parameter through pre-configured correspondence, allowing the UE to derive transmission parameters from existing control channel parameters without additional signaling.
2Reliability
If the UE transmits more repetitions of uplink control messages, then the reliability of message delivery is improved, but the uplink resource consumption and transmission time increase
Solution Approach 1:
The PUCCH repetition factor is dynamically adjusted based on the aggregation level of the received PDCCH. Higher aggregation levels (indicating better downlink control channel conditions) map to higher repetition factors, while lower aggregation levels map to lower repetition factors. This dynamic adaptation allows the system to optimize uplink resource usage according to real-time channel conditions, transmitting more repetitions only when necessary for reliability.
Solution Approach 2:
The system uses the aggregation level of the PDCCH as feedback about downlink channel conditions to implicitly control uplink transmission repetition. The base station selects the aggregation level based on downlink channel quality, and the UE uses this aggregation level to determine the appropriate repetition factor, creating a feedback loop that adapts transmission parameters to channel conditions without explicit signaling.
3Reliability
If the base station selects higher aggregation levels for PDCCH, then the reliability of downlink control information delivery is improved, but the downlink resource consumption increases
Solution Approach 1:
The aggregation level of the PDCCH serves dual functions: it ensures reliable downlink control information delivery by providing redundancy against downlink channel errors, and simultaneously serves as an implicit indication mechanism for the UE to determine the PUCCH repetition factor. This multi-functionality eliminates the need for separate signaling resources for indicating repetition factors, making the downlink control channel more efficient.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. Generally, a base station may implicitly indicate a physical uplink control channel (PUCCH) repetition factor for a user equipment (UE) to use on a next PUCCH via the selection of an aggregation level for the preceding physical downlink control channel (PDCCH). For example, the base station may configure relationships between PUCCH repetition factors and aggregation levels. To determine which PUCCH repetition factor the UE should use, the base station may select the corresponding aggregation level, and may transmit a downlink control message (e.g., a downlink control information (DCI) message) on a PDCCH using the selected aggregation level that corresponds to the desired PUCCH repetition factor.