Adaptive DMRS Reference Signal Patterns for Relative-Speed Links
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Solution Overview
Problem
Existing wireless communication systems face inefficiencies in transmitting reference signals due to varying relative speeds between user equipment (UEs), leading to poor quality or excess overhead signaling, resulting in ineffective spectral use and poor sidelink performance.
Innovation Solution
Adaptive reference signal patterns are designed based on the relative speed between UEs, adjusting the density of demodulation reference signals (DMRS) to optimize transmission efficiency by increasing density at high speeds and decreasing it at low speeds, using assistance information, HARQ feedback, or base station scheduling to determine optimal patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the density of demodulation reference signals is increased to improve decoding accuracy at high relative speeds, then sidelink performance is improved, but signaling overhead increases
Solution Approach 1:
The patent implements dynamic adjustment of reference signal density based on relative speed conditions. The system transitions from static reference signal patterns to adaptive patterns that change according to the relative speed between transmitting and receiving UEs. This allows the density of demodulation reference signals to be increased only when high relative speed conditions are detected, thereby improving decoding accuracy only when necessary while avoiding unnecessary overhead during low-speed conditions.
Solution Approach 2:
The patent changes the parameter of reference signal density based on relative speed measurements. By measuring the relative speed between UEs and adjusting the reference signal pattern parameters accordingly, the system optimizes the balance between decoding accuracy and signaling overhead. Different reference signal patterns with varying densities are selected based on speed thresholds, allowing the system to adapt to different channel conditions caused by varying relative speeds.
2Quantity of substance
If the density of demodulation reference signals is decreased to reduce signaling overhead at low relative speeds, then spectral efficiency is improved, but decoding accuracy deteriorates
Solution Approach 1:
The system dynamically adjusts reference signal density based on real-time relative speed measurements. When low relative speeds are detected, the system automatically reduces reference signal density to minimize overhead, while maintaining sufficient signals for accurate decoding. This dynamic adaptation ensures that the system maintains optimal performance across varying speed conditions without consistently using high-density patterns that would waste spectral resources.
Solution Approach 2:
The patent implements parameter changes in reference signal patterns based on relative speed conditions. By selecting from multiple predefined patterns with different densities, the system adjusts the reference signal parameters to match the current speed regime. This ensures that sufficient reference signals are present for accurate decoding at low speeds while avoiding excessive overhead that would reduce spectral efficiency.
3Device complexity
If fixed reference signal patterns are used regardless of relative speed, then device complexity is reduced, but spectral efficiency deteriorates
Solution Approach 1:
The patent introduces dynamic adaptation mechanisms that adjust reference signal patterns based on relative speed measurements. The system incorporates speed measurement capabilities and pattern selection logic that automatically adapts to changing conditions. While this increases device complexity compared to fixed patterns, the improvement in spectral efficiency through optimized reference signal density justifies the additional complexity, particularly in scenarios with varying relative speeds between UEs.
Data Source
AI summary
Methods, systems, and devices for wireless communications (e.g., vehicle to everything systems) are described relating to an adaptive design of demodulation reference signals (DMRS) density based on user equipment (UE) velocity. A UE may send assistance information to a transmitting UE to help identify a DMRS pattern based on the relative speed between the two UEs. Also, the transmitter may determine the adaptive DMRS pattern based on its speed without information of the receiver's speed. The transmitter may indicate the adaptive DMRS pattern in control information to the receiver. A base station may receive assistance information, and the base station may determine the adaptive DMRS pattern to be used by the transmitting UE based on the received assistance information and then indicate the adaptive DMRS pattern to the transmitting UE. A UE may determine an adaptive DMRS pattern to use based on feedback from the receiving UE.