Joint Phase Noise and Channel Estimation Using PC-RS
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Solution Overview
Problem
Wireless communication systems operating in the millimeter wave (mmW) spectrum face challenges due to higher phase noise levels, which lead to signal reception errors and degraded system performance, particularly because traditional UE components generate phase noise and have reduced capabilities compared to components used in lower frequency systems.
Innovation Solution
The implementation of a method where a base station transmits both Phase Noise Compensation Reference Signals (PC-RS) and Channel State Information Reference Signals (CSI-RS) to a User Equipment (UE), allowing the UE to jointly estimate channel and phase noise, and provide phase noise corrected channel measurements, enabling improved resource assignment and modulation schemes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If millimeter wave transceivers use higher frequency local oscillators to achieve mmW communication, then communication frequency band is improved, but phase noise level increases
Solution Approach 1:
The patent segments the channel estimation process into two distinct parts: traditional channel estimation using CSI-RS and phase noise estimation using PC-RS. This segmentation allows each reference signal to be optimized for its specific purpose, with PC-RS specifically designed to measure phase noise characteristics without being contaminated by channel effects.
Solution Approach 2:
The patent introduces PC-RS as an intermediary reference signal that mediates between the high-frequency mmW transmission and the phase noise measurement requirement. PC-RS serves as a dedicated tool to isolate and measure phase noise, which then can be used to correct the main data transmission, improving overall reception accuracy.
2Device complexity
If traditional UE components are used in mmW systems, then device complexity is reduced, but phase noise generation increases
Solution Approach 1:
The patent implements a feedback mechanism where the UE measures phase noise using PC-RS, reports the phase noise characteristics back to the base station, and the base station uses this information to adjust transmissions. This feedback loop allows traditional UE components to operate while their phase noise characteristics are continuously measured and compensated for.
Solution Approach 2:
The patent enables the UE to self-measure and self-report its phase noise characteristics using the PC-RS. The UE autonomously performs phase noise estimation on received PC-RS signals and includes this information in CSI reports, allowing the system to adapt to the specific UE's phase noise profile without requiring more complex hardware.
3Measurement precision
If phase noise correction is implemented using PC-RS and CSI-RS, then channel measurement accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent merges the phase noise estimation function with the existing CSI reporting framework. Instead of creating a separate feedback channel for phase noise, the phase noise information is combined with channel state information in the existing CSI reports, efficiently utilizing existing uplink resources.
Solution Approach 2:
The patent makes the CSI reporting mechanism multi-functional by enabling it to carry both traditional channel state information and phase noise measurement information. This universality allows a single feedback message to serve multiple purposes, reducing the need for additional dedicated signaling resources.
Data Source
AI summary
Methods, systems, and devices for wireless communication are described. A base station may transmit a phase noise correction reference signal (PC-RS) and a channel state information reference signal (CSI-RS) during a symbol period of a subframe. A user equipment (UE) may identify a first channel information using the PC-RS and the CSI-RS. The UE may transmit a channel information message to the base station that includes the first channel information. The first channel information may include a phase noise corrected channel measurement. The UE may the CSI-RS during the symbol period. Channel and phase noise estimates may be generated using a joint estimation based on the CSI-RS. The CSI-RS may be repeated periodically. In some cases, the UE may additionally or alternatively receive pilot tones that may include PC-RSs. The joint estimation may be further based on the pilot tones.