PT-RS Design for Single-Carrier Waveforms in 5G NR
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Solution Overview
Problem
Current wireless communication systems, particularly in the 5G new radio (NR) context, face challenges in phase noise and frequency offset compensation, especially at carrier frequencies above 52.6 GHz, where existing waveforms like OFDM struggle with low power amplifier efficiency and large phase noise, necessitating enhanced phase tracking reference signal (PT-RS) designs for single-carrier based waveforms.
Innovation Solution
The implementation of a phase tracking reference signal (PT-RS) design for single-carrier waveforms, including DFT-s-OFDM and SC-FDE, which involves inserting PT-RS within data blocks for both downlink and uplink transmissions, using specific patterns and power boosting, and employing different modulation orders for PT-RS to ensure effective phase compensation and reduce receiver complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If OFDM waveform is used for high-frequency transmission, then data transmission capability is improved, but phase noise and frequency offset compensation becomes difficult
Solution Approach 1:
The reference signal is segmented into multiple PT-RS ports with different modulation orders (e.g., QPSK for first port, 16QAM for second port). This segmentation allows the system to use higher-order modulation for phase tracking while maintaining robustness through lower-order modulation, thereby improving phase noise compensation reliability without sacrificing data transmission capability
Solution Approach 2:
The patent changes the modulation order parameter of reference signals based on channel conditions and frequency bands. By dynamically adjusting modulation order (e.g., using QPSK in high-frequency bands with high phase noise, and 16QAM or 64QAM in lower-frequency bands), the system optimizes the balance between data transmission efficiency and phase tracking accuracy
2Measurement precision
If higher modulation order is used for PT-RS, then phase tracking accuracy is improved, but receiver complexity increases
Solution Approach 1:
Different modulation orders are assigned to different PT-RS ports based on local requirements. The first PT-RS port uses lower modulation order (QPSK) for robust phase tracking, while the second PT-RS port uses higher modulation order (16QAM or 64QAM) for enhanced accuracy when needed. This local differentiation allows the receiver to process signals with varying complexity requirements rather than uniformly high complexity
3Use of energy by moving object
If single-carrier waveform is used, then power amplifier efficiency is improved, but phase noise compensation capability deteriorates
Solution Approach 1:
PT-RS acts as an intermediary signal inserted within data blocks of single-carrier waveforms. This intermediary reference signal provides dedicated phase tracking capability without altering the underlying single-carrier waveform structure, thereby maintaining power amplifier efficiency while enabling effective phase noise compensation through separate reference signal processing
Data Source
AI summary
One or more computer-readable media (CRM) are disclosed. The CRM include instructions to, upon execution of the instructions by one or more processors of a base station, cause the base station to: generate a phase tracking reference signal (PT-RS) for phase shift compensation; and transmit the PT-RS across a physical downlink shared channel (PDSCH) using a single-carrier based waveform comprising a carrier frequency. The single-carrier based waveform may be SC-FDE or DFT-s-OFDM.