UCI Retransmission Signaling for HARQ-ACK Decode Failures
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Solution Overview
Problem
The large signaling overhead and low transmission reliability of uplink control information (UCI) in 3GPP 5G new radio (NR) networks, particularly due to UE power limitations, burst interference, and cross-link interference, result in inefficient retransmissions of downlink transport blocks when UCI is not decoded, degrading network performance.
Innovation Solution
Implementing a system where the base station (gNB) sends an indicator to the user equipment (UE) when UCI is not correctly decoded, allowing for scheduled retransmissions of UCI with a UCI process ID, and configuring a timer for UCI storage and retransmission, optimizing UCI reliability through controlled retransmission processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the UCI payload size is increased to include more HARQ-ACK feedback bits, then the coverage of downlink transmissions is improved, but the transmission reliability deteriorates due to lower SINR and higher coding rate
Solution Approach 1:
The patent segments the UCI retransmission process into multiple attempts with different resource allocations. The first retransmission uses the same resources as the initial transmission, while subsequent retransmissions use additional resources. This segmentation allows the system to adapt to different reliability requirements without always using maximum resources, thus resolving the contradiction between payload capacity and transmission reliability.
Solution Approach 2:
The patent implements dynamic resource allocation for UCI retransmissions based on the decoding outcome. The gNB determines the number of retransmission attempts and allocates resources dynamically. This dynamic approach allows the system to optimize between payload capacity and reliability by adjusting resources based on actual transmission conditions and outcomes.
2Reliability
If more retransmission attempts are made for UCI, then the transmission reliability is improved, but the loss of time increases due to extended retransmission duration
Solution Approach 1:
The patent performs preliminary actions by configuring the maximum number of retransmission attempts and setting up the retransmission timeline in advance through RRC signaling. The gNB pre-determines the retransmission schedule and resources, allowing the UE to prepare for potential retransmissions without causing unnecessary time delays. This preliminary configuration enables efficient retransmission when needed while avoiding unnecessary time consumption.
Solution Approach 2:
The patent uses feedback mechanisms where the gNB sends indication information to the UE about the decoding outcome of UCI. Based on this feedback, the system determines whether retransmission is necessary and how many attempts should be made. This feedback-driven approach ensures that retransmission time is only consumed when actually needed, optimizing the balance between reliability and time loss.
3Reliability
If the UE transmission power is increased to improve UCI reliability, then the transmission reliability is improved, but the burst interference from neighboring cells increases
Solution Approach 1:
The patent segments the UCI transmission into multiple retransmission attempts with different power levels and resource allocations. Instead of always using maximum power, the system can use lower power for initial transmissions and only increase power for subsequent retransmissions if needed. This segmentation reduces the overall burst interference impact while maintaining reliability through selective power adjustment.
Solution Approach 2:
The patent changes transmission parameters including power level, resource allocation, and timing based on the transmission outcome. The gNB can adjust these parameters dynamically to optimize reliability without always using maximum power. By changing parameters adaptively, the system achieves reliable UCI transmission while minimizing burst interference to neighboring cells.
4Productivity
If dynamic TDD is used to optimize downlink performance, then the downlink throughput is improved, but the cross-link interference to UCI transmission increases
Solution Approach 1:
The patent uses feedback mechanisms where the gNB receives UCI decoding outcomes and adjusts downlink transmission parameters accordingly. Based on this feedback, the system can optimize the TDD configuration and resource allocation to minimize cross-link interference while maintaining high downlink throughput. The feedback loop enables adaptive optimization that balances productivity and interference reduction.
Solution Approach 2:
The patent implements dynamic adjustment of TDD parameters and resource allocation based on real-time transmission conditions. The gNB can dynamically reconfigure downlink transmissions to avoid interfering with UCI retransmissions, especially when interference is detected. This dynamic approach allows the system to maintain high throughput while adapting to minimize cross-link interference.
Data Source
AI summary
Methods and apparatuses for retransmitting uplink control information. An apparatus comprising: a receiver that receives uplink control information (UCI) from a remote unit, wherein the UCI includes hybrid automatic repeat request acknowledgement (HARQ-ACK) feedback corresponding to a plurality of downlink transmissions; a processor that decodes the UCI; and a transmitter that, in response to the UCI not being correctly decoded, transmits downlink control information (DCI) including a first signaling to the remote unit, wherein the first signaling includes an indicator indicating that the UCI is not correctly decoded and an identification corresponding to the UCI.