DM-RS Symbol Placement for Channel Estimation in 5G NR
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Solution Overview
Problem
Current wireless communication systems, particularly 5G NR, face challenges in optimizing the placement and configuration of demodulation reference signals (DM-RS) within scheduling units, which affects channel estimation and performance, especially in high-speed and high-density environments.
Innovation Solution
The method involves determining the locations of DM-RS symbols within a scheduling unit based on the duration of the unit, number of control symbols, and deployment scenarios, allowing for flexible configuration of DM-RS positions such as preamble, midamble, and postamble symbols, and selecting between predefined families of DM-RS locations to improve channel tracking and system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If DM-RS symbols are placed at fixed predetermined positions, then device complexity is reduced, but adaptability to different deployment scenarios deteriorates
Solution Approach 1:
The patent implements dynamic DM-RS configuration by allowing the network to selectively activate different DM-RS location patterns (first pattern with front-loaded DM-RS, second pattern with distributed DM-RS) based on deployment scenarios. The apparatus determines DM-RS locations adaptively rather than using fixed positions, enabling the system to switch between configurations to match varying channel conditions and service requirements.
2Measurement precision
If more DM-RS symbols are transmitted, then channel estimation accuracy is improved, but resource overhead increases
Solution Approach 1:
The patent applies local quality by placing DM-RS symbols at specific strategic locations rather than uniformly distributing them. The first pattern concentrates DM-RS at the beginning of the scheduling unit for rapid channel estimation, while the second pattern distributes them for tracking time-varying channels. This localized placement optimizes channel estimation accuracy at critical points without unnecessarily increasing overall resource overhead.
Solution Approach 2:
The patent uses partial action by transmitting only the necessary number of DM-RS symbols required for adequate channel estimation in different scenarios. Rather than always transmitting maximum DM-RS symbols, the system selectively activates patterns with appropriate DM-RS densities, achieving sufficient channel estimation accuracy while minimizing resource consumption.
3Quantity of substance
If DM-RS symbols are spaced further apart, then resource overhead is reduced, but channel tracking capability deteriorates
Solution Approach 1:
The patent implements periodic action by distributing DM-RS symbols at regular intervals within the scheduling unit according to the second pattern. This periodic placement ensures that channel tracking capability is maintained at consistent intervals throughout the transmission, allowing the system to monitor and track channel variations reliably while optimizing the spacing to reduce resource overhead compared to continuous DM-RS transmission.
Data Source
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AI summary
In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus maybe a base station or a UE. In an aspect, the apparatus may determine locations for a number of DM-RS symbols to be transmitted in a scheduling unit of a channel configured in a slot/mini-slot, where a last DM-RS symbol maybe positioned one symbol prior to a last symbol carrying scheduled data. In another aspect, the apparatus may determine the locations for the DM-RS symbols based on a selection between a first set of predetermined DM-RS positions and a second set of predetermined DM-RS positions. In another aspect, the apparatus may determine the locations for the DM-RS symbols based on a set number of symbols, wherein the determined locations are spaced apart according to the set number of symbols. The apparatus may transmit the DM-RS symbols based on the determined locations.