TRP-Specific HARQ-ACK Codebook Design for Multi-TRP Wireless Feedback
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Solution Overview
Problem
In wireless communications systems, user equipment (UE) faces challenges in transmitting acknowledgement (ACK) feedback to multiple transmission reception points (TRPs) simultaneously due to non-ideal backhaul connections, leading to inefficiencies and potential collisions in uplink messages.
Innovation Solution
The UE is allocated separate slots for ACK feedback to each TRP, with TRP-specific HARQ-ACK codebooks and uplink parameters determined based on downlink control information and TRP-specific parameters, allowing for sequential transmission of ACK feedback to prevent collisions and optimize resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the UE transmits ACK feedback to multiple TRPs simultaneously, then the feedback transmission efficiency is improved, but the uplink message collisions occur due to non-ideal backhaul connections
Solution Approach 1:
The patent segments the uplink feedback transmission by allocating separate time slots to different TRPs. Each TRP is assigned specific slots for receiving HARQ-ACK feedback, which divides the simultaneous transmission problem into sequential transmissions. This segmentation eliminates collisions while maintaining comprehensive feedback coverage across multiple TRPs.
2Reliability
If separate slots are allocated for ACK feedback to each TRP, then the uplink message collisions are prevented, but the signaling overhead increases
Solution Approach 1:
The patent merges the slot allocation information into the downlink control information (DCI) messages that are already being transmitted to the UE. By incorporating slot allocation indicators into existing DCI structures, the system avoids separate signaling overhead while still providing the necessary slot allocation information to the UE for collision-free feedback transmission.
3Measurement precision
If the UE determines TRP-specific HARQ-ACK codebooks, then the feedback accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent applies local quality by determining HARQ-ACK codebooks specific to each TRP based on TRP-specific parameters and downlink control information. Each TRP receives customized feedback codebooks tailored to its specific configuration, channel conditions, and service requirements. This localized approach improves feedback accuracy for each TRP while the systematic methodology keeps the overall complexity manageable.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive a slot allocation to provide hybrid automatic repeat request (HARQ) acknowledgement (ACK) feedback to multiple transmission reception points (TRPs). For example, each TRP may be allocated at least one slot for HARQ-ACK feedback such that HARQ-ACK feedback for different TRPs may not be transmitted in a same slot. Additionally, the UE may determine a TRP-specific HARQ-ACK codebook for feedback transmissions to each TRP in their corresponding slots. In some cases, the UE may also determine TRP-specific uplink parameters for the feedback transmissions to each TRP. The UE may then transmit feedback to a TRP using a corresponding slot from the slot allocation and using the TRP-specific HARQ-ACK codebook and the TRP-specific uplink parameters.