Distributed Antenna Clock Synchronization for Autonomous Vehicles
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Solution Overview
Problem
In autonomous vehicle systems with a distributed antenna structure, there is a need for synchronizing clocks between the main controller and antenna units, as well as between the autonomous vehicle and a base station, to ensure proper data transmission and reception, while also compensating for clock errors between distributed units.
Innovation Solution
A method involving a distributed antenna system with a baseband modem that calculates frequency offsets for each RF path, controls the oscillator clock of the central unit based on these offsets, and synchronizes the oscillator clocks of distributed units, either by setting them to individual values in tracking mode or a common value in acquisition mode, to ensure accurate clock synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a distributed antenna structure is used to improve wireless communication performance, then communication reliability is improved, but clock synchronization complexity increases
Solution Approach 1:
The patent introduces a baseband modem as an intermediary component that centrally manages clock synchronization for all distributed antenna units. The baseband modem calculates frequency offsets and generates control signals to adjust oscillator clocks in each distributed unit, thereby simplifying the overall synchronization architecture while maintaining communication reliability across the distributed antenna system.
Solution Approach 2:
The patent implements a feedback mechanism where the baseband modem continuously monitors frequency offsets in each RF path and dynamically adjusts oscillator clock frequencies accordingly. This closed-loop feedback system automatically compensates for clock drift and synchronization errors, maintaining reliable communication without requiring complex manual synchronization configurations.
2Measurement precision
If frequency offset calculation is performed for each RF path to improve measurement precision, then clock synchronization accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent consolidates the frequency offset calculation and processing functions into a single baseband modem that serves all distributed antenna units. Instead of each distributed unit independently calculating and managing its own frequency offsets, the baseband modem performs all calculations centrally and distributes control signals, thereby improving measurement precision while reducing overall processing complexity through functional consolidation.
3Measurement precision
If oscillator clocks of distributed units are individually controlled to improve synchronization precision, then time tracking accuracy is improved, but system complexity increases
Solution Approach 1:
The patent segments the clock control function by separating the oscillators in each distributed unit from the control logic. The oscillators are distributed across multiple units for precision control, while the control logic is centralized in the baseband modem. This segmentation allows individual oscillator adjustment for high time tracking accuracy while maintaining manageable system complexity through centralized management.
Solution Approach 2:
The baseband modem acts as an intermediary between the central controller and the distributed oscillators. It receives synchronization requirements, calculates appropriate frequency adjustments for each RF path, and generates control signals to adjust individual oscillators. This intermediary layer enables precise individual oscillator control without requiring direct complex interactions between all system components.
Data Source
AI summary
A control method of a distributed antenna system (DAS) including a baseband modem, according to one embodiment, may comprise the steps of: calculating frequency offsets for each RF path in the baseband modem; controlling an oscillator clock of a central unit (CU) on the basis of an average of the frequency offsets; determining an operation mode of the baseband modem; and controlling oscillator clocks of each distributed unit (DU) on the basis of the frequency offsets for each RF path when the operation mode of the baseband modem is a tracking mode.