PUCCH HARQ-A Scheduling for Multi-TRP Non-Ideal Backhaul
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Solution Overview
Problem
In wireless communications systems with multiple transmission reception points (TRPs) and non-ideal backhaul links, efficient coordination and differentiation of physical uplink control channel (PUCCH) resources for hybrid automatic repeat request (HARQ-A) are challenging due to reduced backhaul capacity and data rates.
Innovation Solution
The solution involves techniques for UE to differentiate and schedule PUCCH transmissions to multiple TRPs by processing DCI from each TRP, using K1 and PRI index values to identify associated TRPs, and scheduling HARQ-A payloads separately for each TRP, with RRC signaling configuring PUCCH resource sets and beam indications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If PUCCH resources are shared across multiple TRPs, then device complexity is reduced, but communication reliability deteriorates due to non-ideal backhaul links
Solution Approach 1:
The patent segments PUCCH resources by creating separate resource sets for different TRPs. Each TRP is assigned specific PUCCH resources, allowing independent management and transmission. This segmentation resolves the contradiction by maintaining separate resource paths for each TRP, ensuring reliability despite non-ideal backhaul while keeping individual TRP resource management simple.
Solution Approach 2:
The patent introduces an intermediary mechanism through RRC signaling that configures and differentiates PUCCH resources for different TRPs. The RRC layer acts as an intermediary that establishes the mapping between TRPs and specific PUCCH resources, enabling reliable separate transmissions without requiring complex real-time coordination at the physical layer.
2Reliability
If separate PUCCH resources are allocated for each TRP, then HARQ-A feedback reliability is improved, but device complexity increases
Solution Approach 1:
The patent implements a universal RRC signaling mechanism that handles configuration for multiple TRPs through a unified framework. The same RRC procedures and signaling structures are reused across different TRPs, allowing the system to manage separate resources for each TRP without proportionally increasing complexity. The universal configuration approach enables scalable management of multiple TRPs.
3Productivity
If PUCCH transmissions are coordinated through ideal backhaul, then communication efficiency is improved, but adaptability to non-ideal backhaul environments deteriorates
Solution Approach 1:
The patent introduces dynamic adaptability by allowing the system to adjust PUCCH resource allocation and transmission parameters based on actual backhaul conditions. Rather than relying on fixed ideal backhaul assumptions, the system dynamically configures resources through RRC signaling to match the actual network conditions, maintaining efficiency in non-ideal environments.
Solution Approach 2:
The patent changes key parameters such as PUCCH resource indices, timing offsets, and frequency allocations to adapt to non-ideal backhaul conditions. By modifying these parameters through RRC reconfiguration, the system optimizes communication efficiency for the actual backhaul quality without requiring ideal conditions, enabling versatile operation across different backhaul scenarios.
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AI summary
Methods, systems, and devices for wireless communications that support physical uplink control channel (PUCCH) carrying hybrid automatic repeat request (HARQ-A) for multiple transmission reception point (multi-TRP) environments with non-ideal backhaul links are described. A user equipment (UE) may support multiple communication links with TRPs and receive distinct physical downlink control channel (PDCCH) messages that include downlink control information (DCI). The DCI may include a timing or resource indication index values for physical uplink control channel (PUCCH) transmission. Based on the index values, the UE may differentiate the received DCI indications. The UE may then schedule PUCCH transmissions, including hybrid automatic repeat request (HARQ) payloads, directed to the TRPs. In some examples, the scheduling may include mapping the PUCCH transmissions to resources or resource groups in configured PUCCH resource set. The UE may then transmit the PUCCH messages via one or more determined beams based on the indication index values.