Uplink PTRS Port Mapping for Eight-Layer Phase Tracking

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Solution Overview

Problem

Existing wireless communication systems face challenges in supporting a higher number of transmit chains, such as eight, due to limitations in phase tracking reference signals (PTRS) antenna port configurations, leading to incomplete phase noise error detection, increased latency, and inefficient resource use.

Innovation Solution

Enhanced PTRS antenna port configurations and usage are implemented to support up to eight transmission layers, allowing UEs to transmit capability signaling for up to four PTRS antenna ports, with network entities configuring mappings via RRC or DCI signaling for SRS and DMRS ports, and using updated lookup tables for time and frequency densities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If PTRS antenna port configurations are limited to two ports, then device complexity is reduced, but the system cannot support eight transmit chains and transmission reliability deteriorates

Engineering Contradiction:

ImprovePTRS antenna port configuration complexityVSAvoidphase noise error detection completeness

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent implements dynamic PTRS antenna port configuration where the network can flexibly allocate 1, 2, or 4 PTRS antenna ports based on the number of active transmit chains and transmission requirements. This dynamic adaptation allows the system to scale PTRS resources with the transmit chain count, ensuring complete phase noise error detection across 1-8 transmit chains while avoiding unnecessary complexity when fewer ports are needed.

Inventive Principle:

Principle #15Dynamics

2Reliability

If PTRS antenna ports are increased to support eight transmit chains, then transmission reliability improves, but device complexity and resource overhead increase

Engineering Contradiction:

Improvephase noise error detection completenessVSAvoidPTRS antenna port configuration complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements partial action by configuring PTRS antenna ports only when and where needed. Instead of always using 4 PTRS ports, the system dynamically allocates 1, 2, or 4 ports based on the actual number of active transmit chains (1-8). This ensures complete phase noise error detection for the active chains while avoiding the complexity and resource overhead of configuring all 4 ports unnecessarily.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent changes the PTRS antenna port parameter dynamically based on transmission conditions. The network configures different numbers of PTRS antenna ports (1, 2, or 4) according to the number of active transmit chains and channel conditions, allowing the system to adapt PTRS resources to match actual transmission requirements and optimize the balance between reliability and complexity.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If capability signaling is implemented for PTRS antenna ports, then adaptability to different UE configurations improves, but signaling overhead increases

Engineering Contradiction:

ImproveUE PTRS support configurationVSAvoidsignaling overhead

Core Design Contradiction:

Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent implements preliminary action by having the UE pre-indicate its capability to support up to 4 PTRS antenna ports through capability signaling before actual transmission. This allows the network to plan and configure appropriate PTRS resources in advance, avoiding the need for extensive dynamic negotiation during transmission and reducing overall signaling overhead while maintaining adaptability.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12580709B2Uplink phase tracking reference signals for multiple transmitters on uplink shared channels

Publication Date: 2026.03.17 QUALCOMM INC

AI summary

Methods, systems, and devices for wireless communications are described. The described techniques provide for phase tracking reference signal (PTRS) antenna port configuration and use to support a number of transmission layers (e.g., up to eight transmission layers). In some examples, a user equipment (UE) may be able to support up to four PTRS antenna ports. The UE may transmit capability signaling indicating a number of supported PTRS antenna ports (e.g., up to 4). The network entity may transmit control signaling indicating a number of PTRS antenna ports and a mapping between the PTRS antenna ports and other ports (e.g., sounding reference signal (SRS) ports or demodulation reference signal (DMRS) ports). In some examples, the UE may also indicate a requested number of PTRS antenna ports (e.g., which may be the same as or less than the supported number of PTRS antenna ports).