Dynamic PUCCH Repetition for Reliable NR Msg4 HARQ-ACK Feedback
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Solution Overview
Problem
There is a need for improved techniques in 5G New Radio (NR) technology to enhance the reliability of Physical Uplink Control Channel (PUCCH) transmissions, particularly in scenarios with large coverage requirements, where a single HARQ-ACK transmission repetition may not be reliable enough.
Innovation Solution
A method where a User Equipment (UE) receives a system information block (SIB) containing a set of candidate repetition factors for PUCCH transmissions and determines a specific repetition factor based on its capability and dynamic indications, transmitting an acknowledgement (ACK) or negative acknowledgement (NACK) of a message 4 of the random access procedure in accordance with the determined repetition factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single HARQ-ACK transmission repetition is used for PUCCH, then the device complexity is reduced, but the reliability of transmission is insufficient in large coverage scenarios
Solution Approach 1:
The patent implements dynamic repetition factor adjustment where the UE can adaptively select from multiple candidate repetition factors based on channel conditions and coverage requirements. The repetition factor is determined dynamically through interaction between UE capability reporting and gNB configuration, allowing the system to optimize between reliability and complexity in real-time rather than using a fixed single repetition approach
Solution Approach 2:
The patent changes the parameter of repetition factor from a fixed value to a configurable parameter with multiple candidate values. The gNB configures a set of candidate repetition factors and dynamically indicates which one to use based on current network conditions, while the UE reports its capability to support certain repetition factors. This parameter change enables flexible adaptation to different coverage scenarios
2Adaptability or versatility
If the UE reports capability for PUCCH repetition in message 3, then the adaptability of the system is improved, but the loss of time in the random access procedure increases
Solution Approach 1:
The patent applies preliminary action by having the UE report its PUCCH repetition capability during the random access procedure in message 3, before actual PUCCH transmissions occur. This advance capability reporting allows the gNB to have prior knowledge of the UE's repetition support, enabling efficient configuration selection without requiring additional signaling rounds later, thus minimizing time loss while maintaining adaptability
3Adaptability or versatility
If multiple candidate repetition factors are configured in SIB, then the adaptability to different coverage scenarios is improved, but the quantity of information to be processed increases
Solution Approach 1:
The patent implements partial action by configuring a set of candidate repetition factors in the SIB rather than specifying a single factor or all possible factors. The gNB provides a limited subset of relevant candidate values that cover typical coverage scenarios, and the UE selectively processes only those candidates it supports. This approach provides sufficient adaptability for most cases while limiting the quantity of configuration information to manageable levels
Data Source
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AI summary
A UE (250) receives a system information block (SIB) from a base station (210). The UE (250) determines whether the SIB includes a set of candidate repetition factors for physical uplink control channel (PUCCH) transmissions. The UE (250) transmits, to the base station (210) in a message of a random access procedure, an indication of a capability of the UE (250) for PUCCH repetition in response to determining that the SIB includes the set of candidate repetition factors. When the UE (250) has the capability, the UE (250) determines a particular repetition factor based on at least one of the set of candidate repetition factors and a dynamic indication of a repetition factor. When the UE (250) has the capability, the UE (250) further transmits an acknowledgement (ACK) or negative acknowledgement (NACK) of a message 4 of the random access procedure in a PUCCH in accordance with the particular repetition factor.