DM-RS and PT-RS Joint Mapping for Lower NR Pilot Overhead
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Solution Overview
Problem
Existing solutions for joint design of DM-RS and PT-RS in NR are limited to scenarios with a single DM-RS instance, and there is a need to manage pilot contamination and overhead of reference signals effectively.
Innovation Solution
A method for joint mapping of DM-RS and PT-RS based on the position of the front-loaded DM-RS in the slot, required time density, and positions of the first and last symbols for data transmission, aligning PT-RS with DM-RS to reduce overhead and maintain estimation quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If PT-RS and DM-RS are scheduled independently without joint mapping, then each reference signal can be configured separately, but the total reference signal overhead increases and pilot contamination occurs
Solution Approach 1:
The patent applies joint mapping of PT-RS and DM-RS by combining their scheduling decisions into a unified process. The PT-RS mapping is determined based on the DM-RS position, allowing both reference signals to share time-frequency resources more efficiently. This merging approach reduces the total number of resource elements occupied by reference signals while maintaining the ability to configure different time densities and positions for each signal type.
2Reliability
If PT-RS time density is increased to compensate for phase noise at high frequencies, then phase noise compensation improves, but the reference signal overhead increases
Solution Approach 1:
The patent implements dynamic configuration of PT-RS time density as a variable parameter. The time density can be set to different values (e.g., 1, 1/2, 1/4) depending on the operational requirements, carrier frequency, and phase noise conditions. This allows the system to adjust the PT-RS density to the minimum necessary level for adequate phase noise compensation, thereby reducing overhead when high density is not required.
3Adaptability or versatility
If DM-RS position is changed to support different modulation and coding schemes, then adaptation to channel conditions improves, but the reference signal mapping complexity increases
Solution Approach 1:
The patent implements dynamic DM-RS positioning where the DM-RS can be scheduled at different positions within the slot depending on the selected modulation and coding scheme. The system can adapt the DM-RS position dynamically based on channel conditions and MCS requirements. This dynamic approach allows optimal reference signal placement for different transmission scenarios without requiring complex manual configuration.
Data Source
AI summary
A method, network node and wireless device in a wireless communication system for one of transmitting and receiving a phase tracking-reference signal, PT-RS. The method includes obtaining information about a position in a time domain of a scheduled first demodulation reference signal, DM-RS, in a slot, and one of transmitting and receiving the PT-RS within the slot, the position of the PT-RS depending on the position in the time domain of the scheduled first DM-RS.