8 Tx Uplink MIMO via Segmented PTRS and DCI
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Solution Overview
Problem
Current 3GPP new radio (NR) systems are limited to uplink multiple-input, multiple-output (MIMO) operation with a maximum of four transmitters (Tx) and four transmission layers for the physical uplink shared channel (PUSCH).
Innovation Solution
The proposed solution enhances the PTRS (Phase Tracking Reference Signal) configuration and DCI (Downlink Control Information) signaling to support 8 Tx PUSCH operation, enabling full-power transmission and reducing DCI size through optimized coherency modes and antenna port groupings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the system supports up to four transmitters and four transmission layers for PUSCH as per current 3GPP NR standards, then the system maintains compatibility with existing standards and implementations, but the system cannot achieve enhanced uplink MIMO capacity and performance with eight transmitters
Solution Approach 1:
The eight antenna ports are divided into two groups of four ports each, with each group associated with a separate codebook and PTRS port. This segmentation allows the system to support 8-Tx operation by treating each group as an independent 4-Tx entity, thereby achieving enhanced capacity while managing complexity through modular codebook design and separate phase tracking reference signal ports for each group
Solution Approach 2:
The patent extends the existing 4-Tx system architecture to 8-Tx by adding a new dimension of antenna port grouping. Instead of simply increasing the number of ports linearly, the system organizes ports into hierarchical groups (two groups of four), creating a two-level structure that enables 8-Tx operation while maintaining compatibility with existing 4-Tx codebook designs and processing frameworks
2Productivity
If the system increases the number of antenna ports to eight, then the uplink transmission capacity is enhanced, but the DCI signaling size increases and processing complexity increases
Solution Approach 1:
The DCI signaling is segmented to include separate codebook group indicators for each of the two codebook groups. Rather than requiring a single large codebook for eight ports, the system uses two smaller codebooks with their own indicators, thereby reducing the overall signaling overhead while maintaining the ability to specify precise precoding for all eight antenna ports
Solution Approach 2:
The system performs preliminary configuration of codebook groups and their associated parameters through higher-layer signaling (RRC configuration) before actual PUSCH transmission. This preliminary action allows the DCI to reference pre-configured codebook groups using compact indicators, thereby reducing real-time DCI overhead while maintaining flexibility for different transmission scenarios
3Measurement precision
If the system uses eight antenna ports with separate phase tracking, then the transmission accuracy is maintained, but the PTRS configuration complexity and processing overhead increase
Solution Approach 1:
The phase tracking is segmented by creating separate PTRS ports for each codebook group of four antenna ports. This segmentation maintains phase tracking accuracy for each group independently while avoiding the need for a single complex eight-port PTRS configuration, thereby managing processing overhead through modular phase tracking handling
Solution Approach 2:
The PTRS ports serve as intermediaries between the DMRS ports and the phase estimation process. Each PTRS port is associated with a specific codebook group and provides the necessary phase reference signals for accurate channel estimation and compensation within that group, thereby maintaining overall system phase tracking accuracy while simplifying the configuration through group-based association
Data Source
AI summary
The present application relates to devices and components including apparatus, systems, and methods for supporting eight transmitter uplink operation.