Carrier Frequency Offset Estimation for RF Sensing
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Solution Overview
Problem
Existing wireless communication systems face challenges in accurately estimating carrier frequency offsets (CFOs) during radio frequency for sensing (RF-S) operations, which affects precise Doppler shift estimation and overall RF sensing accuracy.
Innovation Solution
The method involves determining the capability of user equipment (UE) to estimate CFOs and transmitting this capability to a network component. The network component then configures reference signal (RS) transmission and receives measurement information to estimate the CFO of the UE, enabling accurate RF-S operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional CFO estimation methods are used in RF-S operations, then the system maintains simplicity, but the Doppler shift estimation precision deteriorates
Solution Approach 1:
The network component configures reference signal transmissions before actual RF-S operations to enable preliminary CFO estimation. The UE transmits reference signals at configured time instances, allowing the network to estimate CFO values in advance, which are then used to compensate for frequency offsets during actual sensing operations, improving Doppler shift estimation precision without adding complexity to the core sensing function
Solution Approach 2:
Reference signals serve as an intermediary mechanism between the UE and the network component for CFO estimation. Instead of directly estimating CFO during RF-S operations, the system uses dedicated reference signal transmissions as a mediator to carry pilot information that enables indirect but more accurate CFO estimation, which subsequently improves the precision of Doppler shift measurements
2Measurement precision
If CFO estimation is performed using dedicated reference signal transmissions, then the CFO estimation accuracy improves, but the signaling overhead and operation time increase
Solution Approach 1:
The system merges CFO estimation functionality with existing reference signal infrastructure. Instead of creating separate dedicated estimation channels, the solution combines CFO estimation with uplink reference signals (such as SRS - Sounding Reference Signals) that already exist in the system for other purposes like channel quality indication, thereby achieving accurate CFO estimation without proportionally increasing overhead or time consumption
Solution Approach 2:
The network component configures specific transmission parameters for reference signals (such as frequency shifts, time instances, and resource allocations) to optimize CFO estimation accuracy. By carefully selecting and adjusting these parameters, the system achieves high estimation precision while minimizing the time and resource overhead associated with reference signal transmissions
Data Source
AI summary
Disclosed are techniques for wireless signaling. In an aspect, a user equipment (UE) transmits, to a network component, an indication of a capability to estimate a carrier frequency offset (CFO) of the UE associated with radio frequency for sensing (RF-S) operations. In another aspect, the network component estimates the CFO of the UE (e.g., based on measurement information from the UE and/or wireless node(s)). In some designs, the network component further transmits, to the UE, the CFO of the UE (e.g., for CFO compensation associated with RF-S sensing operation(s)).