HARQ-ACK Feedback Timing for Multi-PDSCH Scheduling
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Solution Overview
Problem
Existing wireless communication systems lack a specific scheme to extend the K1 set for HARQ-ACK feedback timing and determine which set of PDSCH receptions are associated with the extended K1 set, especially in FR 2-2 (52.6-71GHz), where multiple PDSCHs can be non-continuous in time-domain, and current specifications are limited to single DCI scheduling.
Innovation Solution
The proposed solution involves extending the K1 set for HARQ-ACK feedback timing based on the time domain resource assignment (TDRA) table and determining an association between the extended K1 set and PDSCH receptions, allowing for semi-static HARQ-ACK codebook generation for multiple PDSCHs scheduled by a single DCI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the UE transmits feedback in the earliest available uplink slot to minimize latency, then the feedback delay is reduced, but the feedback may be transmitted before the UE has completely received or decoded the downlink transmission
Solution Approach 1:
The network configures multiple candidate feedback timing indicators in advance (PDI values), allowing the UE to select the appropriate timing based on actual reception conditions. This preliminary configuration enables the system to prepare multiple timing options before transmission occurs, resolving the contradiction between early feedback and complete reception.
Solution Approach 2:
The feedback timing becomes dynamic rather than fixed - the UE selectively determines the PDI value based on whether it has completely received the downlink transmission. This dynamic adjustment allows the system to adapt feedback timing to actual channel conditions and reception status, achieving both low latency and high reliability.
2Device complexity
If the network uses a fixed feedback timing configuration, then the system complexity is reduced, but the system cannot adapt to varying channel conditions and transmission lengths
Solution Approach 1:
The system changes the timing parameter (PDI value) based on channel conditions and transmission characteristics. By configuring multiple PDI values and allowing selective determination, the system maintains flexibility to adapt to different scenarios while keeping the underlying mechanism relatively simple.
Solution Approach 2:
The UE autonomously determines the appropriate PDI value based on its own reception status and channel conditions, without requiring complex network control for each timing decision. This self-service approach reduces overall system complexity while maintaining adaptability.
3Reliability
If the UE waits for complete reception before transmitting feedback, then feedback reliability is improved, but the overall system latency increases
Solution Approach 1:
Multiple feedback timing options are pre-configured in the network, allowing the system to select appropriate timing in advance based on reception completion status. This eliminates the need for complex real-time decisions while maintaining both reliability and low latency.
Solution Approach 2:
The feedback timing is dynamically adjusted based on actual reception conditions - the UE can transmit earlier when reception is complete or slightly later when needed, selecting from pre-configured PDI values. This dynamic behavior resolves the contradiction between waiting for complete reception and minimizing latency.
Data Source
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AI summary
A method of wireless communication is described. The method includes obtaining, by a user device, a parameter set used to determine a feedback timing, the parameter set including N elements; and modifying the parameter set to include M elements, M being greater than N, based on a time domain resource assignment table that includes information on multiple physical downlink shared channel receptions, whereby N and M are positive integers.