DMRS Mapping Pattern Shift for sTTI Collision Avoidance
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently configuring demodulation reference signals (DMRS) for shortened transmission time intervals (sTTIs), particularly in avoiding collisions with other reference signals and optimizing DMRS mapping patterns based on the number of layers and reference signal configurations.
Innovation Solution
A baseline DMRS mapping pattern is identified and shifted based on the number of layers for a user equipment (UE) and reference signal configurations, allowing for effective mapping of DMRS data to resource elements within sTTIs, avoiding collisions with other reference signals and optimizing resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If DMRS is mapped to resource elements in sTTI to enable channel estimation, then demodulation capability is improved, but collision with other reference signals (CSI-RS, CRS) occurs reducing reliability
Solution Approach 1:
The patent applies local quality by configuring different DMRS mapping patterns for different resource element locations within the sTTI. Specifically, DMRS is mapped to different REs depending on the presence and position of other reference signals (CSI-RS, CRS) in that local region, ensuring optimal channel estimation without collision at each specific location
Solution Approach 2:
The patent implements preliminary action by pre-configuring the DMRS mapping pattern based on the anticipated positions of other reference signals before the actual transmission occurs. The base station determines the appropriate mapping pattern in advance, allowing the UE to properly demodulate data without experiencing collisions
2Device complexity
If DMRS mapping pattern is fixed to simplify configuration, then device complexity is reduced, but adaptability to different layer configurations and reference signal patterns is limited
Solution Approach 1:
The patent applies dynamics by making the DMRS mapping pattern configurable and adaptable to different transmission scenarios. Instead of a fixed pattern, the system can dynamically select from multiple mapping patterns (e.g., pattern 1, pattern 2, pattern 3) based on the number of layers, presence of other reference signals, and specific sTTI configuration, maintaining low complexity through standardized options while achieving high adaptability
Solution Approach 2:
The patent implements parameter changes by varying the DMRS mapping pattern parameters (such as the specific resource elements used for DMRS) based on the number of layers and reference signal configuration. This allows the same basic DMRS structure to adapt to different scenarios by changing its mapping parameters rather than requiring entirely different structures
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AI summary
Methods, systems, and devices for wireless communications are described. One method may include identifying a baseline demodulation reference signal (DMRS) mapping pattern for mapping of DMRS data to resource elements (REs) within a shortened transmission time interval (sTTI) based on a number of layers for which a user equipment (UE) is configured. In some examples, the number of layers may be configured on a per-unit basis. The method may further include determining a shifted DMRS mapping pattern based on the baseline DMRS mapping pattern and a reference signal configuration associated with reference signals other than a DMRS, configuring REs within the sTTI according to the shifted DMRS mapping pattern, and transmitting the configured REs.