LF-HF Communication Synchronization for Automotive Access
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Solution Overview
Problem
Existing communication systems face challenges with timing misalignment, interference, and thermal noise, particularly in applications like automotive access, which affect synchronization and authentication, leading to increased latency and power consumption.
Innovation Solution
The implementation of a method using low-frequency (LF) and high-frequency (HF) communication circuits where LF signals are used for synchronization and damping to reduce phase ambiguity, followed by HF signals with predetermined time delays for secure communication and authentication, minimizing power consumption and latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional RF ranging systems use time-of-flight principle for distance determination, then positioning capability is achieved, but timing misalignment and signal degradation occur
Solution Approach 1:
The communication process is divided into multiple phases: LF signal transmission for initial synchronization, HF signal transmission for precise ranging, and re-synchronization steps. This segmentation allows each phase to address specific requirements, with LF handling coarse alignment and HF handling fine positioning, thereby resolving the contradiction between measurement precision and reliability.
Solution Approach 2:
The system changes frequency parameters by using low-frequency (LF) signals for initial synchronization and high-frequency (HF) signals for precise ranging. This parameter change allows the system to achieve both robust synchronization (at LF) and high measurement precision (at HF), resolving the contradiction between reliability and measurement precision.
2Reliability
If packet data communication uses long preambles for synchronization, then timing alignment is achieved, but latency increases
Solution Approach 1:
The system performs preliminary synchronization using LF signals before HF packet data transmission. This preliminary action establishes timing alignment in advance, allowing the subsequent HF communication to proceed with minimal preamble overhead, thereby reducing latency while maintaining timing reliability.
Solution Approach 2:
LF signals act as an intermediary mechanism that performs coarse synchronization before the main HF data transmission. This intermediary step handles the timing alignment function that would otherwise require long preambles in the HF signals, thereby reducing latency while maintaining synchronization reliability.
3Reliability
If traditional synchronization methods are used, then device authentication is achieved, but power consumption increases
Solution Approach 1:
The system uses periodic LF signal transmissions for synchronization and authentication, followed by HF signal exchanges. This periodic action pattern allows devices to maintain authentication reliability through repeated verification while managing power consumption by limiting the duration of high-power HF operations to only when necessary.
Solution Approach 2:
The system changes operational parameters by using low-power LF signals for initial authentication and synchronization, reserving high-power HF signals for precise ranging and data transmission. This parameter change strategy maintains authentication reliability while significantly reducing overall power consumption by minimizing the time spent at high power levels.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces timing uncertainty, minimizes power requirements, and facilitates secure communication by synchronizing devices with reduced latency and power consumption, effectively addressing issues of timing alignment and authentication in communication systems.
Implementation Method 1
transmitting a first low-frequency (LF) signal from the local device to the remote device; at the remote device, synchronizing a first clock based on the first LF signal
Implementation Method 2
processing the second LF signal with a reduced quality factor at the local and remote devices, therein facilitating detection of the second LF signal at the remote device with reduced phase ambiguity
Implementation Method 3
using the re-synchronized first clock to communicate a first high-frequency (HF) signal from the first device to the second device with a first predetermined time delay
Data Source
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AI summary
Aspects of the present disclosure provide communications between local and remote devices having low-frequency (LF) and high-frequency (HF) circuits. As may be implemented in accordance with one or more embodiments, the local device transmits an LF signal to the remote device, which synchronizes its clock based on the LF signal. Another LF signal is communicated from the local device to the remote device using a reduced quality factor, which can be implemented to facilitate synchronization. The clock is resynchronized based on the second LF signal and used to transmit an HF signal with a time delay. The local device synchronizes its clock based on the HF signal, and transmits another HF signal to the remote device using the clock and another time delay. The remote device re-synchronizes its clock based on the second HF signal while accounting for a trip time for communicating the first and/or second HF signals.