Adaptive PTRS Allocation for Phase Noise Demodulation
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Solution Overview
Problem
Phase noise becomes a significant component of the overall noise for downlink signals in wireless communication systems, especially at higher carrier frequencies, affecting the demodulation of higher-order constellations and increasing the operational signal to noise ratio requirement, while existing phase tracking reference signals (PTRS) increase overhead, complexity, and latency.
Innovation Solution
A method for efficient PTRS allocation that maps residual integrated phase noise powers (RIPNPs) to subcarriers, allowing for optimized PTRS transmission based on threshold accuracy, overhead, power consumption, and latency, using non-continuous frequency resources and continuous PTRS configurations to mitigate phase noise effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional PTRS is used for phase noise mitigation, then phase noise estimation accuracy is improved, but overhead and complexity increase
Solution Approach 1:
The patent segments the frequency domain into multiple subsets and selectively applies PTRS only to specific subsets based on channel conditions and phase noise characteristics. This segmentation allows the system to concentrate reference signal resources where they are most needed, improving estimation accuracy in critical frequency regions while reducing overall overhead and complexity compared to uniform PTRS application across all frequencies.
2Reliability
If PTRS is increased to improve phase noise mitigation, then demodulation reliability is improved, but throughput is reduced due to overhead
Solution Approach 1:
The patent implements dynamic PTRS configuration where the number, position, and density of PTRS are adaptively adjusted based on real-time channel conditions, phase noise characteristics, and service requirements. This dynamic approach allows the system to optimize the balance between demodulation reliability and throughput by increasing PTRS only when and where phase noise mitigation is critical, rather than using fixed overhead configurations.
3Measurement precision
If continuous frequency resources are used for PTRS, then phase noise estimation accuracy is improved, but resource utilization efficiency decreases
Solution Approach 1:
The patent applies local quality by making PTRS density and distribution non-uniform across different frequency subsets, matching the local phase noise characteristics and channel conditions in each region. Instead of using continuous uniform frequency resources, the system concentrates PTRS in frequency regions with higher phase noise variance or more challenging channel conditions, while reducing or eliminating PTRS in regions with better conditions, thereby improving resource utilization efficiency while maintaining estimation accuracy where it matters most.
Data Source
AI summary
The apparatus may be a wireless device configured to transmit, for a network device, a first indication mapping each of a plurality of residual integrated phase noise powers (RIPNPs) to a corresponding number of subcarriers, receive, based on the first indication, a second indication of a number of subcarriers including a phase tracking reference signal (PTRS), receive, via one or more symbols, a transmission including a data signal and the PTRS over the number of subcarriers indicated in the second indication, and perform a demodulation of the data signal using a phase noise estimation based on the PTRS. The apparatus may be a network device configured to obtain, from a wireless device, the first indication, output, based on the first indication, the second indication, and transmit, via one or more symbols, the transmission including the data signal and the PTRS.