PDSCH DMRS Bundling With Front-Loaded Density for Coherent Decoding
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Solution Overview
Problem
Existing wireless communication systems, particularly 5G NR, face challenges in efficiently processing physical downlink shared channel (PDSCH) demodulation reference signals (DMRS) due to variations in DMRS symbol density across slots, which affects signal coherence and processing efficiency.
Innovation Solution
Implementing a method where DMRS symbols are bundled across multiple slots, with a higher density at the beginning of the bundle, and using phase coherent bundling techniques to enhance signal processing, specifically through Mode 2 dynamic bundling indicated by PDCCH.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DMRS symbols are uniformly distributed across all slots, then the system complexity is reduced, but the signal processing gain and coherence deteriorate
Solution Approach 1:
The patent applies local quality by configuring different DMRS symbol densities for different slots within the same bundling group. Specifically, the first slot in each bundling group has a higher DMRS symbol density (e.g., 2 DMRS symbols per slot) while subsequent slots have a lower density (e.g., 1 DMRS symbol per slot). This localized differentiation optimizes signal coherence where most needed while reducing overall system complexity.
2Measurement precision
If DMRS symbol density is increased across all slots, then the decoding accuracy of PDSCH is improved, but the overhead and resource consumption increase
Solution Approach 1:
The patent implements partial action by providing enhanced DMRS density (excessive action) only in the first slot of each bundling group, while using standard density in subsequent slots. This partial enhancement is sufficient to establish phase coherence for the entire bundling group, achieving good decoding accuracy without the excessive overhead of high density across all slots.
3Power
If phase coherent bundling is implemented across multiple slots, then the signal processing gain is enhanced, but the requirement for precise DMRS synchronization increases
Solution Approach 1:
The patent applies preliminary action by placing higher density DMRS symbols in the first slot of each bundling group before phase coherent processing across multiple slots. This preliminary enhanced reference signal provides a stronger synchronization foundation, making the subsequent phase coherent bundling more robust and reducing the stringent synchronization requirements that would otherwise be needed.
Data Source
AI summary
A configuration that enables a UE to process a PDSCH DMRS bundle having a higher density of DMRS symbols at a beginning of the PDSCH DMRS bundle. The apparatus receives a PDSCH and DMRS in each slot of a plurality of slots, the DMRS being bundled across the plurality of slots, a first subset of slots of the plurality of slots each having a higher DMRS symbol density of DMRS than a second subset of slots of the plurality of slots, the second subset of slots being subsequent to the first subset of slots. The apparatus decodes each received PDSCH based on at least a subset of the received DMRS.