Enhanced DM-RS for Multi-TRP PDCCH Transmission
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Solution Overview
Problem
Current 5G NR systems face limitations in PDCCH capacity and robustness, especially with single TRP transmission, which restricts the ability to support high aggregation levels and reliable low-latency communications, particularly in scenarios requiring multiple TRPs for enhanced transmission.
Innovation Solution
The implementation of enhanced Demodulation Reference Signal (DM-RS) with multiple beams from multiple Transmit and Receive Points (TRPs), utilizing a processor to determine and activate Transmission Configuration Indication (TCI) states and transmit PDCCH over multiple TRPs, along with implicit TCI state determination and orthogonal DM-RS sequences to improve demodulation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If single TRP transmission is used for PDCCH, then device complexity is reduced, but PDCCH capacity and robustness deteriorate
Solution Approach 1:
The PDCCH transmission is segmented into multiple TRPs, where each TRP transmits PDCCH using separate DM-RS resources. This segmentation allows the system to maintain multiple transmission paths independently, improving robustness without requiring a completely complex unified transmission structure.
Solution Approach 2:
The patent introduces a new dimension of transmission by utilizing multiple TRPs in the spatial domain, moving from single-point to multi-point transmission. This dimensional expansion increases PDCCH capacity and robustness while managing complexity through structured resource allocation.
2Reliability
If multiple TRPs are used for PDCCH transmission, then PDCCH capacity and robustness are improved, but device complexity increases
Solution Approach 1:
Each TRP is configured with local DM-RS resources and specific TCI states, allowing independent optimization of each transmission point. This local quality approach enables robust multi-TRP transmission while managing overall system complexity through modular configuration.
Solution Approach 2:
The patent utilizes TCI states to dynamically change transmission parameters such as beamforming vectors and resource allocation for each TRP. This parameter-based control allows flexible adaptation to different channel conditions without hardcoding complex transmission structures.
3Measurement precision
If multiple TCI states are activated for multi-TRP PDCCH, then channel estimation accuracy is improved, but signaling overhead increases
Solution Approach 1:
TCI states are pre-configured and activated through MAC CE before PDCCH transmission begins. This preliminary action allows the receiver to have channel estimation parameters ready in advance, improving accuracy while reducing real-time signaling overhead during actual transmission.
Data Source
AI summary
Apparatus and methods of enhanced DM-RS for enhanced PDCCH transmission with multiple beams from multiple TRPs are disclosed. The apparatus includes: a processor that determines a plurality of activated Transmission Configuration Indication (TCI) states for transmission of a Physical Downlink Control Channel (PDCCH) with Demodulation Reference Signal (DM-RS) in a Control Resource Set (CORESET), using a plurality of wireless transmitting-receiving identities, wherein the CORESET comprises a plurality of transmission units having a predefined granularity; and determines one of the TCI states to be used for each of the transmission units and its corresponding DM-RS, based on a TCI state mapping scheme; and a transmitter that transmits a Media Access Control (MAC) Control Element (CE) for activating each of the TCI states; and transmits the PDCCH over the transmission units and the corresponding DM-RS with the corresponding TCI states as determined by the processor, using the plurality of wireless transmitting-receiving identities.