PUCCH Repetition for HARQ-ACK in Random Access
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Solution Overview
Problem
In wireless communication systems, particularly in 5G NR, there is a lack of repetition mechanisms for Physical Uplink Control Channel (PUCCH) transmissions before dedicated PUCCH resource configuration, leading to high probability of Hybrid Automatic Repeat Request (HARQ) ACK failure due to large distances in non-terrestrial networks, which affects coverage and reliability during random access procedures.
Innovation Solution
Implementing PUCCH repetition for HARQ-ACK feedback messages prior to dedicated PUCCH resource configuration, allowing the receiver to combine data copies and enhance decoding, thereby improving coverage and reliability during random access procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PUCCH repetition is implemented before dedicated PUCCH resource configuration, then coverage and reliability are improved, but device complexity and signaling overhead increase
Solution Approach 1:
The patent applies preliminary action by configuring PUCCH repetition parameters before dedicated PUCCH resource configuration is activated. The base station sends RRC configuration messages containing repetition factors and resource set information in advance, allowing the UE to perform repeated PUCCH transmissions during random access procedures before dedicated resources are established. This resolves the contradiction by enabling reliability improvement through repetition while managing complexity through pre-configuration rather than on-the-fly decisions.
Solution Approach 2:
The patent utilizes parameter changes by introducing configurable repetition factors (numberOfRepetitions) and associating different PUCCH resource sets with different repetition configurations. The base station can dynamically adjust repetition parameters through RRC messages based on channel conditions and UE capabilities. This allows the system to balance reliability and complexity by adapting repetition levels rather than always using maximum repetition, thus managing device complexity while maintaining reliability improvements.
2Adaptability or versatility
If multiple PUCCH resource sets with different repetition factors are configured, then adaptability to different channel conditions is improved, but device complexity and processing overhead increase
Solution Approach 1:
The patent applies local quality by creating different PUCCH resource sets with different repetition factors tailored to specific channel conditions or UE capabilities. Each resource set is optimized for particular scenarios (e.g., one resource set for good channel conditions with low repetition, another for poor conditions with high repetition). The UE selects the appropriate resource set based on current channel quality, thus achieving adaptability while managing complexity through localized optimization rather than uniform configuration.
Solution Approach 2:
The patent implements dynamics by allowing the base station to activate different PUCCH resource sets with different repetition factors based on real-time channel conditions and UE feedback. The configuration is not static but can be dynamically adjusted through RRC reconfiguration messages. This enables the system to adapt to changing conditions while managing device complexity through controlled dynamic behavior rather than requiring the UE to handle all possible configurations simultaneously.
3Reliability
If PUCCH repetition is used for HARQ ACK feedback, then message delivery success rate is improved, but transmission time and latency increase
Solution Approach 1:
The patent applies partial or excessive action by configuring a maximum repetition factor that may not always be fully utilized. The actual number of repetitions performed depends on whether the transmission is successful or fails. If the first few repetitions succeed, the full configured repetition count is not executed, thus reducing average latency. This resolves the contradiction by preparing for worst-case scenarios (excessive action) while allowing early termination in successful cases (partial action), maintaining reliability without always incurring maximum time penalty.
Data Source
AI summary
Aspects are provided for enhancing HARQ ACK for Message 4 or Message B. An apparatus may obtain a configuration indicating a number of repetitions for a physical uplink control channel (PUCCH) transmission in a plurality of slots prior to activation of a dedicated PUCCH resource configuration with a plurality of repetitions based on a radio resource control (RRC) message. The PUCCH transmission includes a Hybrid Automatic Repeat Request (HARQ) feedback message in response to receiving a message on a Physical Downlink Shared Channel (PDSCH) in a random access procedure. The PUCCH transmission may then be transmitted on a PUCCH according to the number of repetitions. This allows coverage techniques to be applied to certain transmissions in order to improve coverage and reliability. In an aspect, the coverage enhancement techniques may include repetition of a transmission for coverage extension.