Dynamic DM-RS Allocation for High-Frequency Channel Estimation
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Solution Overview
Problem
Existing mobile communication systems face challenges in efficiently allocating demodulation reference signal (DM-RS) resources, particularly in high-frequency bands like 5G and beyond, due to increased phase noise and propagation loss, which affect channel estimation and data decoding accuracy.
Innovation Solution
Implementing dynamic DM-RS resource allocation methods, including frequency shift/hopping of DM-RS as a function of OFDM symbols, DM-RS antenna port aggregation, and enhanced PDCCH DMRS, to increase frequency density and improve channel estimation in high-frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If DM-RS resource allocation is increased to improve channel estimation accuracy in high-frequency bands, then channel estimation accuracy improves, but system resource overhead increases
Solution Approach 1:
The patent implements dynamic DM-RS resource allocation where the frequency density and pattern of DM-RS are adjusted based on channel conditions, mobility states, and service requirements. This allows the system to increase DM-RS density only when necessary for channel estimation accuracy, rather than using fixed high density throughout, thereby resolving the contradiction between measurement precision and resource overhead
Solution Approach 2:
The patent applies different DM-RS density patterns and frequency shift strategies to different time-frequency resources based on local channel conditions. In regions with high phase noise or poor channel conditions, higher DM-RS density is applied, while in stable regions, lower density suffices. This localized adaptation optimizes channel estimation accuracy where needed while minimizing overall resource overhead
2Reliability
If frequency shift/hopping of DM-RS is increased to combat phase noise in high-frequency bands, then channel estimation robustness improves, but signal complexity increases
Solution Approach 1:
The patent employs periodic frequency shifting and hopping patterns for DM-RS that are synchronized with the phase noise characteristics of high-frequency bands. By applying frequency shifts at regular intervals corresponding to phase noise cycles, the system maintains robust channel estimation without requiring continuous complex signal processing, thus improving reliability while managing complexity
Solution Approach 2:
The patent dynamically adjusts DM-RS frequency shift parameters based on detected phase noise characteristics, mobility conditions, and channel quality. By changing frequency shift magnitudes and hopping patterns adaptively, the system achieves robust channel estimation in high-frequency bands while avoiding unnecessary complexity in stable conditions
3Measurement precision
If DM-RS antenna port aggregation is used to increase frequency density, then channel estimation accuracy improves, but processing complexity increases
Solution Approach 1:
The patent aggregates multiple DM-RS antenna ports to increase frequency density and improve channel estimation accuracy. By combining reference signals from multiple ports, the system achieves better spatial and frequency diversity for channel estimation. The processing complexity is managed through efficient port aggregation algorithms that exploit correlations between ports
4Productivity
If dynamic DM-RS resource allocation is implemented to optimize performance, then communication performance improves, but control signaling overhead increases
Solution Approach 1:
The patent implements dynamic DM-RS resource allocation through pre-configured patterns and parameter sets that are signaled in advance via RRC configuration. The actual dynamic selection uses compact indicators in DCI that reference pre-agreed patterns, rather than signaling full DM-RS configurations. This preliminary action reduces real-time control signaling overhead while maintaining the ability to optimize communication performance adaptively
Data Source
AI summary
Systems, apparatus and methods are described for dynamic demodulation signal resource allocation. PDSCH/PUSCH DMRS enhancement is provided. A dynamic indication of reference signal functionality may be provided in a slot for an additional DM-RS. A configured CSI-RS/SRS may be dynamically indicated to use as an additional DM-RS in a slot. Frequency shift/hopping of DM-RS as a function of OFDM symbol and/or the order of OFDM symbol containing DM-RS may increase frequency density within a slot. DM-RS antenna port aggregation may increase DM-RS frequency density. One or more DM-RS antenna ports may be used to demodulate the same layer. PDCCH DMRS enhancement is provided. Frequency shift/hopping of PDCCH DMRS may be provided as a function of a REG index within an REG bundle, OFDM symbol index, etc. Use of multiple types of REG (e.g., low and high DM-RS) and REG type may be determined based on subcarrier spacing, operating frequency band, etc.