Phase Tracking Reference Signal Power Boosting for mmWave Phase Noise
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Solution Overview
Problem
Wireless communication systems, particularly those operating in the millimeter wave (mmWave) spectrum, face significant challenges in managing phase noise, which degrades link performance and increases with frequency and bandwidth, leading to substantial phase errors and power drops.
Innovation Solution
The implementation of enhanced Phase Tracking Reference Signal (PTRS) techniques, including power boosting, dynamic time/frequency density adjustments, and multi-port configurations, to compensate for phase noise, while maintaining power spectral density within regulatory limits, and interpolating CPE estimates for improved phase noise correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If oscillators operate at higher RF frequencies to enable mmWave communication, then bandwidth and transmission speed are improved, but phase noise increases causing link performance degradation
Solution Approach 1:
The patent introduces Phase Tracking Reference Signals (PTRS) as an intermediary element to mediate between the high-frequency oscillator and the communication link. These reference signals are inserted into the transmitted signal at specific time and frequency positions, serving as mediators that carry phase information. The receiver uses these intermediary PTRS signals to estimate and compensate for phase noise, thereby maintaining link performance despite operating at high frequencies with increased phase noise
Solution Approach 2:
The patent implements a feedback mechanism where the receiver estimates phase noise based on received PTRS signals and generates compensation information. This compensation information is fed back to correct the phase errors in the received signal. The feedback loop continuously monitors and corrects phase deviations, allowing the system to maintain reliability despite the inherent phase noise at high transmission frequencies
2Measurement precision
If PTRS density is increased to improve phase noise estimation accuracy, then phase noise correction is improved, but spectral efficiency decreases
Solution Approach 1:
The patent makes the PTRS configuration dynamic by allowing the network to adaptively adjust the time and frequency density of PTRS based on channel conditions, phase noise characteristics, and service requirements. The PTRS parameters such as time density (every 1, 2, or 4 slots) and frequency density (every 1, 2, or 4 subcarriers) can be dynamically changed, enabling the system to optimize between phase noise estimation accuracy and spectral efficiency according to real-time conditions
Solution Approach 2:
The patent changes the parameters of PTRS transmission by introducing configurable time and frequency density parameters. Instead of fixed PTRS placement, the system varies the time interval and frequency spacing of PTRS based on operational requirements. This parameter adjustment allows the system to reduce PTRS overhead when phase noise is manageable while maintaining sufficient estimation accuracy, thereby preserving spectral efficiency
3Measurement precision
If power boosting is applied to PTRS to enhance phase tracking accuracy, then phase noise compensation is improved, but power spectral density constraints may be violated
Solution Approach 1:
The patent applies local quality by concentrating additional power specifically on the PTRS resources rather than uniformly increasing power across all resources. The power boosting is localized to the specific time-frequency positions where PTRS are transmitted, enhancing the signal-to-noise ratio for phase tracking only where needed. This localized power enhancement improves phase tracking accuracy without unnecessarily increasing overall transmit power and potential regulatory violations
Data Source
AI summary
Various techniques are presented to improve phase tracking reference signal (PTRS) performance with respect to very high frequency communications. According to some embodiments, increased power boosting may be applied to improve PTRS performance, while still keeping power spectral density (PSD) within ETSI Broadband Radio Access Networks (BRAN) limits. In some cases, the power boosting may be semi-static and/or dynamic. In other embodiments, the improved performance may be achieved by dynamically changing time and/or frequency density of the PTRS. In other embodiments, a multi-port configuration may be used for the downlink PTRS. In other embodiments, one or more PTRS configurations may be determined per SCS and/or frequency band, e.g., based on traffic type, channel priority, parameters signaled in the slot format indication (SFI), etc. In other embodiments, common phase error (CPE) estimates may be obtained for those OFDM symbols without PTRS by interpolating the available PTRS estimates in the time domain.