PUCCH Repetition Control for 5G Random Access Reliability
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Solution Overview
Problem
Current 5G New Radio (NR) technology faces challenges in reliably indicating the number of repetitions for Physical Uplink Control Channel (PUCCH) transmissions, particularly for contention resolution messages, which can be unreliable due to high coverage requirements and varying channel conditions.
Innovation Solution
A method where user equipment (UE) receives a common configuration for candidate repetition factors from a base station, determines a specific repetition factor based on this configuration, and transmits ACK or NACK messages in accordance with it during a random access procedure, enhancing reliability by dynamically adjusting repetition based on channel conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of PUCCH repetitions is increased to improve reliability of contention resolution messages, then the reliability is improved, but the overhead and resource consumption increase
Solution Approach 1:
The patent implements dynamic adjustment of PUCCH repetition factors based on real-time channel conditions. The UE determines the repetition factor by evaluating channel quality indicators and comparing them against thresholds, allowing the system to adaptively increase repetitions only when reliability is compromised by poor channel conditions, rather than using a fixed high repetition count. This resolves the contradiction by making the system dynamic rather than static.
Solution Approach 2:
The patent changes the parameter of repetition factor based on channel conditions. The UE monitors channel quality and adjusts the repetition factor parameter dynamically - using higher repetition factors when channel conditions are poor and lower factors when conditions are good. This parameter adaptation allows the system to maintain reliability while minimizing overhead, directly resolving the contradiction between these two opposing requirements.
2Reliability
If the repetition factor is dynamically adjusted based on channel conditions, then the reliability is improved, but the complexity of determining the repetition factor increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring threshold values for channel quality indicators and pre-defining mapping relationships between channel conditions and repetition factors. The UE compares measured channel quality against these pre-set thresholds to determine the appropriate repetition factor, rather than performing complex real-time optimization calculations. This reduces the computational complexity while maintaining reliable adaptation to channel conditions.
Solution Approach 2:
The UE performs self-service by autonomously determining its own repetition factor based on its measurement of channel conditions and the pre-configured thresholds provided by the network. The UE does not require complex network-side calculation or coordination - it independently evaluates its channel quality and selects the appropriate repetition factor from the configured set, simplifying the overall system complexity while achieving reliable transmission.
3Device complexity
If a fixed repetition factor is used for all PUCCH transmissions, then the device complexity is reduced, but the adaptability to varying channel conditions deteriorates
Solution Approach 1:
The patent transforms the static fixed repetition factor approach into a dynamic adaptive system. The UE continuously monitors channel conditions and adjusts the repetition factor accordingly, enabling the system to adapt to varying channel conditions while maintaining reasonable complexity through the use of pre-configured thresholds and a limited set of candidate repetition factors.
Solution Approach 2:
The patent enables parameter changes by allowing the repetition factor to vary based on channel conditions. The network configures a set of candidate repetition factors and thresholds, and the UE dynamically selects from these candidates based on measured channel quality, providing adaptability without requiring the system to handle an unlimited range of repetition factors, thus balancing adaptability with complexity.
Data Source
AI summary
In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a user equipment (UE). The UE receives a common configuration from a base station. The common configuration indicates a set of candidate repetition factors for PUCCH transmissions. The UE receives a specific configuration from the base station for selecting a particular repetition factor from the set of candidate repetition factors or a set of default candidate repetition factors. The UE determines the particular repetition factor based on the common configuration and/or the specific configuration. The UE receives a contention resolution message from the base station in a random access procedure. The UE transmits an ACK or NACK of the contention resolution message in a PUCCH in accordance with the particular repetition factor.