Uplink Feedback Multiplexing With Dummy PDUs During PUSCH Skipping
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently multiplexing uplink control indicators (UCI) onto physical uplink shared channels (PUSCH) with repetition skipping, leading to ambiguity and resource inefficiency due to unclear carrier selection and timing constraints.
Innovation Solution
A UE approach involves generating a dummy protocol data unit (PDU) with filler data to multiplex UCI onto an overlapping PUSCH repetition while skipping other repetitions, and a base station approach involves scheduling HARQ-ACK feedback to overlap with early PUSCH repetitions, thereby improving resource efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If PUSCH repetition skipping is enabled to improve resource efficiency, then resource utilization is improved, but UCI multiplexing becomes ambiguous and unreliable
Solution Approach 1:
The patent applies local quality by making different PUSCH repetitions have different functions: early repetitions (within the window) are designated for potential UCI multiplexing while later repetitions are for data transmission only. This local differentiation resolves the ambiguity by clearly specifying which repetitions can carry UCI, thereby maintaining reliability while preserving the resource efficiency benefits of skipping.
Solution Approach 2:
The patent implements preliminary action by establishing a predetermined UCI multiplexing window before PUSCH transmission begins. The UE and base station agree in advance on the time window parameters (offset and duration) during which UCI can be multiplexed. This preliminary configuration eliminates real-time decision ambiguity and ensures reliable UCI delivery even when repetitions are skipped.
2Reliability
If dummy PDU is generated to enable UCI multiplexing on early repetitions, then UCI transmission reliability is improved, but MAC layer complexity increases
Solution Approach 1:
The patent extracts the UCI multiplexing decision logic from the general PUSCH transmission control and isolates it to a specific time window. By separating the early repetitions (within the window) from later repetitions, the MAC layer only needs to make multiplexing decisions for early repetitions, simplifying the overall control logic while ensuring reliable UCI transmission when needed.
Solution Approach 2:
The patent segments the PUSCH repetition sequence into two distinct parts: early repetitions within the UCI multiplexing window and later repetitions outside the window. This segmentation allows the system to apply different handling rules to each segment, reducing MAC layer complexity by limiting the scope of UCI multiplexing decisions to only the early segment.
3Productivity
If HARQ-ACK feedback timing is constrained to overlap with early PUSCH repetitions, then UCI multiplexing efficiency is improved, but scheduling flexibility is reduced
Solution Approach 1:
The patent introduces dynamics by making the UCI multiplexing window configurable rather than fixed. The window parameters (offset and duration) can be adjusted based on traffic conditions, UE capabilities, and network requirements. This dynamic configuration allows the system to optimize UCI multiplexing efficiency for early repetitions while retaining scheduling flexibility to adapt to different scenarios.
Solution Approach 2:
The patent employs parameter changes by allowing the UCI multiplexing window characteristics (time offset, duration, position) to be modified through RRC configuration and MAC control elements. These parameter adjustments enable the system to balance UCI multiplexing efficiency and scheduling flexibility according to specific operational requirements, resolving the contradiction between the two objectives.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive a message scheduling a multi-repetition uplink transmission to a base station. The UE may generate a protocol data unit (PDU) comprising filler data for the multi-repetition uplink transmission based at least in part on a quantity of data in a buffer for transmission to the base station failing to satisfy a threshold. The UE may transmit a repetition of the multi-repetition uplink transmission based at least in part on determining that the repetition overlaps with a feedback message scheduled for transmission to the base station, the repetition comprising the PDU multiplexed with the feedback message. The UE may suppress a transmission of one or more additional repetitions of the multi-repetition uplink transmission that do not overlap with the feedback message based at least in part on the PDU comprising the filler data.