HARQ Codebook Overlap Handling for Deferred SPS Retransmissions
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Solution Overview
Problem
In wireless communication systems, the transmission of semi-persistent scheduling (SPS) hybrid automatic repeat request (HARQ) codebooks can result in collisions and resource wastage due to deferred SPS HARQ codebooks being appended to retransmitted HARQ codebooks, leading to increased signaling overhead and redundant transmissions.
Innovation Solution
A user equipment (UE) detects overlaps between deferred SPS HARQ codebooks and a retransmitted HARQ codebook, and either cancels the transmission of the deferred codebooks or consolidates them into a single transmission in a different slot, reducing redundant transmissions and signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If deferred SPS HARQ codebooks are appended to retransmitted HARQ codebooks, then HARQ information is transmitted, but resource wastage and signaling overhead increase due to duplicate transmissions
Solution Approach 1:
The UE performs preliminary detection to identify when a deferred SPS HARQ codebook transmission overlaps with a retransmitted HARQ codebook before actual transmission occurs. This allows the system to prevent duplicate transmissions in advance by canceling the deferred codebook transmission when overlap is detected, thereby avoiding resource wastage while ensuring HARQ information is still transmitted through the retransmitted codebook
Solution Approach 2:
When an overlap between deferred SPS HARQ codebook and retransmitted HARQ codebook is detected, the system discards the deferred codebook transmission to avoid duplication. The HARQ information is recovered and transmitted through the retransmitted codebook, which already contains the necessary HARQ bits, thus eliminating redundant transmissions
2Reliability
If deferred SPS HARQ codebooks are appended to retransmitted HARQ codebooks, then HARQ information is transmitted, but signaling overhead increases
Solution Approach 1:
The system performs preliminary detection to identify overlaps between deferred SPS HARQ codebooks and retransmitted HARQ codebooks before transmission. When overlap is detected, the deferred codebook transmission is canceled, preventing duplicate signaling and reducing overhead while maintaining complete HARQ information transmission through the retransmitted codebook
3Object-affected harmful factors
If the UE cancels the transmission of deferred SPS HARQ codebook at slot n and defers it to slot n+2, then the transmission collision is avoided, but resource usage increases when both deferred and retransmitted codebooks are scheduled at the same slot
Solution Approach 1:
The UE performs preliminary detection to identify when both a deferred SPS HARQ codebook and a retransmitted HARQ codebook are scheduled for the same slot. When such overlap is detected, the system cancels the deferred codebook transmission, preventing duplicate resource usage while having already avoided the original transmission collision at slot n by deferring to slot n+2
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may detect an overlap between two or more deferred semi-persistent scheduling (SPS) hybrid automatic repeat request (HARQ) codebooks and a retransmitted HARQ codebook. The UE may cancel a transmission of the two or more deferred SPS HARQ codebooks or perform the transmission of the two or more deferred SPS HARQ codebooks in one or more slots. Numerous other aspects are described.