PUCCH Repetition and Frequency Hopping for Low-Latency HARQ-ACK
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently managing hybrid automatic repeat request acknowledgement (HARQ-ACK) feedback for physical uplink control channels (PUCCH), particularly in scenarios requiring low latency, due to restrictions on multiple HARQ-ACK feedback transmissions per uplink slot, which can lead to increased latency and suboptimal performance for delay-sensitive services.
Innovation Solution
Implementing dynamic repetition and frequency hopping factors for PUCCH, allowing multiple instances of PUCCH transmission across uplink slots or sub-slots based on the indicated PUCCH repetition factor, thereby enhancing the flexibility and efficiency of HARQ-ACK feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If multiple HARQ-ACK feedback transmissions are restricted per uplink slot, then system complexity is reduced, but latency increases and performance for delay-sensitive services deteriorates
Solution Approach 1:
The patent applies dynamics by making the PUCCH repetition factor configurable and adaptable based on service requirements. The system dynamically adjusts the number of PUCCH repetitions and applies frequency hopping only when needed (for URLLC services), rather than using a fixed static configuration. This allows the system to optimize between latency and reliability based on the specific service type.
Solution Approach 2:
The patent changes the parameter of PUCCH repetition factor from a fixed value to a configurable parameter that can be adjusted based on service requirements. By allowing the network to configure different repetition factors (e.g., 1, 2, 3, or 4 repetitions) and selectively applying frequency hopping, the system can adapt to different latency and reliability requirements of various services.
2Reliability
If PUCCH repetition factor is increased for URLLC services, then reliability is improved, but uplink resource consumption increases
Solution Approach 1:
The patent segments the uplink resources by applying frequency hopping that divides the PUCCH transmissions across different frequency resources. Instead of using the same frequency resource for all repetitions, the system hops to different frequency offsets, which segments the resource usage and provides frequency diversity while managing overall resource consumption.
Solution Approach 2:
The patent uses frequency hopping to create frequency-domain copies of the PUCCH transmission. By transmitting copies of the HARQ-ACK feedback at different frequency offsets, the system improves reliability through frequency diversity without simply increasing the power or time resources proportionally.
3Reliability
If frequency hopping is applied to PUCCH transmissions, then frequency diversity is improved, but device complexity increases
Solution Approach 1:
The patent applies partial action by enabling frequency hopping only for specific services (URLLC) that require it, rather than applying it universally to all PUCCH transmissions. The network can configure whether frequency hopping is applied based on the service type, reducing the complexity burden on devices that don't require frequency diversity for their services.
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a base station may transmit, and a user equipment (UE) may receive, downlink control information (DCI) scheduling a physical downlink shared channel (PDSCH) and indicating a physical uplink control channel (PUCCH) repetition factor. The UE may transmit, and the base station may receive, a PUCCH that includes hybrid automatic repeat request acknowledgement feedback associated with the PDSCH. In some aspects, one or more instances of the PUCCH are transmitted across one or more uplink slots or sub-slots based at least in part on the PUCCH repetition factor indicated in the DCI. Numerous other aspects are provided.