RE Repetition for Cross-Slot Phase Discontinuity Estimation
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Solution Overview
Problem
Wireless communications systems face challenges in maintaining phase continuity across slots, which hinders cross-slot DMRS combining and accurate channel estimation due to phase discontinuities, leading to ineffective DMRS overhead and signaling performance.
Innovation Solution
Implementing resource element (RE) repetition to transmit and receive data symbol modulation signals across phase discontinuities, allowing phase estimation and adjustment for coherent DMRS combining, thereby mitigating phase discontinuity and improving channel estimation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If phase continuity is not maintained between slots, then the system can support phase changes for different transmission conditions, but cross-slot DMRS combining fails and channel estimation accuracy deteriorates
Solution Approach 1:
The patent introduces a phase reference signal as an intermediary element that mediates between slots with different phases. This reference signal carries phase information that allows the receiver to compensate for phase discontinuities, enabling both phase changes and accurate channel estimation to coexist.
Solution Approach 2:
The patent transmits a copy of the DMRS in the second slot that matches the phase of the DMRS in the first slot. This phase-copied reference allows the receiver to use the first slot's DMRS for channel estimation while accounting for phase changes in the second slot.
2Measurement precision
If DMRS density is increased to improve channel estimation, then channel estimation accuracy improves, but resource overhead increases
Solution Approach 1:
The patent uses a phase-copied DMRS approach where the second DMRS is transmitted with the same phase as the first DMRS. This allows the system to rely more on the first DMRS for channel estimation and use the second DMRS primarily for phase tracking, effectively reducing the estimation burden on the second DMRS and allowing for lower overall DMRS density while maintaining accuracy.
3Reliability
If RE repetition is implemented to maintain phase continuity, then cross-slot DMRS combining succeeds, but resource element overhead increases
Solution Approach 1:
The patent implements RE repetition by copying specific resource elements containing phase reference information from the first slot to the second slot. This selective copying of only the necessary phase reference REs (rather than repeating all REs) maintains phase continuity and enables reliable DMRS combining while minimizing the overhead increase to only the essential reference elements.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. In some systems, a first wireless communication device (e.g., a user equipment (UE) or network entity) may adjust a phase for transmission between a first data transmission and a second data transmission. The phase adjustment may cause phase discontinuity between slots. To support phase estimation at a second wireless communication device, the first wireless communication device may repeat a data symbol modulation signal from the first data transmission in the second data transmission. For example, the data symbol modulation signal may be transmitted via a first resource element (RE) corresponding to a frequency resource of the first data transmission, and the repetition may puncture a second RE corresponding to the same frequency resource of the second data transmission. The second wireless communication device may perform phase estimation using the repetition of the data symbol modulation signal.