OFDM Phase Tracking Across Repeaters and Frequency Translation
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Solution Overview
Problem
Existing wireless communication systems, particularly in 5G NR, face challenges in accurately compensating for common phase errors (CPEs) in Orthogonal Frequency-Division Multiplexing (OFDM) symbols due to phase noise issues, especially when signals are transmitted across different frequency ranges like FR1 and FR2, which degrade system performance.
Innovation Solution
Incorporating Phase Tracking Reference Signals (PT-RSs) transmitted by a base station on a first carrier frequency and forwarded through repeaters to a user equipment (UE) on a second carrier frequency, allowing the UE to estimate and compensate for common phase errors in OFDM symbols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Phase Tracking Reference Signals (PT-RSs) are transmitted through repeaters to enable phase tracking, then phase noise compensation accuracy is improved, but system complexity increases due to additional signal processing requirements
Solution Approach 1:
The patent introduces PT-RSs as intermediary reference signals that are transmitted through repeaters to enable phase tracking. These reference signals serve as mediators between the base station and UE, allowing the UE to estimate and compensate for phase noise introduced by the repeater without requiring complex processing of the entire data signal.
Solution Approach 2:
The patent segments the phase tracking function from the data communication function by using dedicated PT-RSs. This allows independent optimization of phase tracking processing while maintaining data transmission efficiency. The PT-RSs are transmitted in separate resource elements, enabling dedicated processing for phase noise compensation.
2Reliability
If PT-RSs are transmitted on the first carrier frequency and forwarded on the second carrier frequency through repeaters, then phase noise compensation across frequency ranges is improved, but the number of processing steps increases
Solution Approach 1:
The patent implements a feedback mechanism where the UE estimates phase noise using the PT-RSs received from the base station through the repeater, and then uses this estimation to compensate for phase noise in the data signals. This feedback loop enables continuous improvement of signal quality without requiring complex one-time processing.
Solution Approach 2:
The patent performs preliminary phase noise estimation using PT-RSs before processing the data signals. By estimating and compensating for phase noise in advance using the reference signals, the system simplifies subsequent data signal processing while maintaining high reliability.
Data Source
AI summary
A UE receives second baseband signals carried on a second carrier frequency (f2) transmitted by at least one repeater. The second baseband signals carry data signals transmitted from a base station and are derived from first baseband signals carried on a first carrier frequency (f1) transmitted from the base station. The UE estimates CPEs in a first set of OFDM symbols based on PT-RSs included in the received second baseband signals. The PT-RSs are transmitted by the base station on the first carrier frequency (f1) and forwarded to the UE on the second carrier frequency (f2) through the at least one repeater. The UE detects the data signal based on the received second baseband signals and the estimated CPEs in the first set of OFDM symbols.