DMRS Bundling for Uplink Channel Estimation
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Solution Overview
Problem
Conventional wireless communications systems do not support demodulation reference signal (DMRS) bundling for physical uplink shared channel (PUSCH) or physical uplink control channel (PUCCH) repetitions across multiple bundle intervals, limiting channel estimation accuracy and reliability.
Innovation Solution
A method and apparatus for a user equipment (UE) to transmit PUSCH or PUCCH repetitions with different DMRS densities, identifying TTIs that satisfy phase continuity rules, and applying a DMRS mapping pattern across multiple TTIs, allowing for efficient use of system resources and improved reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DMRS bundling is implemented across multiple bundle intervals, then channel estimation accuracy and reliability are improved, but device complexity increases due to the need to track and manage phase continuity across multiple TTIs
Solution Approach 1:
The patent segments the DMRS transmission into different density configurations (first DMRS density and second DMRS density) applied to different sets of TTIs. This segmentation allows the system to manage complexity by processing DMRS bundles in manageable portions rather than attempting to handle all TTIs simultaneously, while still achieving improved channel estimation reliability through the bundled approach.
2Productivity
If different DMRS densities are applied to different TTIs, then system resource efficiency is improved, but measurement precision requirements increase for maintaining phase continuity
Solution Approach 1:
The patent applies different DMRS density configurations to different TTI sets based on local channel conditions and requirements. By making the DMRS density local rather than uniform, the system optimizes resource efficiency in each local region while maintaining phase continuity where needed, thus balancing resource savings with measurement precision requirements.
3Measurement precision
If DMRS enhancement is applied to all uplink transmissions, then channel estimation accuracy is improved, but loss of time increases due to additional DMRS overhead in every TTI
Solution Approach 1:
The patent applies DMRS enhancement partially rather than universally - specifically to only those TTIs that satisfy phase continuity rules and are identified as requiring enhanced estimation. This partial application avoids the time overhead of DMRS in every TTI while still achieving improved channel estimation accuracy where and when it is most beneficial.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. Generally, a base station may configure a user equipment (UE) to perform demodulation reference signal (DMRS) enhancement whereby the UE may transmit physical uplink shared channel (PUSCH) or physical uplink control channel (PUCCH) repetitions with different DMRS densities (e.g., a first DMRS density configuration having a first or default DMRS pattern within a transmission time interval (TTI) that is higher than a second DMRS density configuration having fewer DMRSs than the normal DMRS pattern or no DMRSs within the TTI). The UE may identify TTIs (e.g., slots) that satisfy one or more phase continuity rules, and may perform DMRS enhancement in the identified TTIs, and may restart a mapping sequence indicated in the DMRS mapping pattern at each bundle interval boundary or when consecutive uplink symbol periods within a bundling interval do not satisfy a phase continuity condition.