SPS HARQ Scheduling for Out-of-Order PDSCH Decoding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wireless communication standards, such as 3GPP Rel-15, do not adequately address out-of-order (OOO) scenarios involving semi-persistent scheduling (SPS) of Hybrid Automatic Repeat Request (HARQ) processes, leading to invalid data transmissions and decoding issues, particularly in critical services like ultra-reliable low-latency communication (URLLC).
Innovation Solution
The proposed solution involves defining an out-of-order condition for SPS-based PDSCHs, where the wireless device prioritizes and decodes PDSCHs with higher priority and skips lower priority ones, based on HARQ acknowledgement timing and quality of service, independent of PDCCH timing, to ensure efficient data processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the legacy rule (TS 38.214 section 5.1) is applied to SPS-based PDSCHs, then in-order HARQ operation is maintained, but out-of-order transmissions in critical services like URLLC cannot be supported
Solution Approach 1:
The patent changes the parameter used for determining HARQ processing order from PDCCH timing to PDSCH timing. Specifically, it introduces a new condition where the ending symbol of the first PDSCH is used instead of the ending symbol of the first PDCCH, allowing SPS-based PDSCHs to be processed out-of-order while maintaining reliability for critical services
Solution Approach 2:
The patent makes the HARQ processing behavior dynamic by introducing a priority indicator that can be configured by higher layers. When priority indication is enabled, the WD can dynamically adjust its processing order based on the priority of different SPS configurations, allowing adaptability for different service types including URLLC
2Productivity
If multiple SPS configurations are activated for a WD, then data transmission efficiency is improved, but determining valid OOO conditions becomes complex and ambiguous
Solution Approach 1:
The patent changes the reference parameter for OOO condition determination from PDCCH timing to PDSCH timing. By using the ending symbol of the first PDSCH as the reference point, it provides a clear and unambiguous method for determining whether OOO conditions exist, even when multiple SPS configurations are activated
Solution Approach 2:
The patent introduces an intermediary mechanism by using the PDSCH ending symbol as a mediator between multiple SPS configurations. This intermediary reference point allows the WD to clearly determine valid OOO conditions without direct comparison of PDCCH timings, reducing complexity
3Reliability
If the WD skips decoding of PDSCHs in OOO scenarios according to legacy rules, then processing errors are avoided, but critical URLLC data may be lost
Solution Approach 1:
The patent changes the condition for skipping PDSCH decoding by using PDSCH timing relationships instead of PDCCH timing relationships. This allows the WD to correctly identify valid SPS transmissions even in OOO scenarios, preventing loss of critical data while maintaining decoding validity
Solution Approach 2:
The patent introduces dynamic priority-based processing where the WD can selectively process or skip PDSCHs based on their priority indicators. For high-priority URLLC data, the WD continues decoding even in OOO scenarios, while lower priority data may be skipped, balancing reliability and information loss
Data Source
Figure 1a~1c
Figure 2a~2b
Figure 3a~3d
AI summary
A method and a wireless device for determining out of order (OOO) operation are disclosed. According to one aspect, the processing circuitry is configured to, when at least one physical downlink shared channel (PDSCH) is subject to semi-persistent scheduling (SPS) determine an OOO condition that is independent of a relative timing of physical downlink control channel (PDCCH) signaling, the OOO condition being one of data transmission overlap and out-of-order hybrid automatic repeat request, HARQ, feedback. A method and wireless device for codebook construction are disclosed. According to one aspect, a method includes constructing a codebook by combining a first codebook and a second codebook, the first codebook being configured for hybrid automatic repeat request (HARQ) acknowledgment (ACK) response of dynamically scheduled physical shared channels and the second codebook being configured for HARQ-ACK response of semi-persistently scheduled (SPS) physical shared channels.