OFDM Arrival Angle Detection via Sub-Carrier Phase Analysis
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Solution Overview
Problem
Current wireless road charge reception systems face issues with erroneous vehicle detection due to the inability to accurately calculate radio wave arrival angles in OFDM-type communication systems, where multiple sub-carrier waves are multiplexed, leading to incorrect charging of vehicles.
Innovation Solution
A radio wave arrival angle detection device that resolves partial signals from multiplexed carrier waves into sub-carrier wave groups, calculates arrival angles based on phase differences and antenna positions, and includes units for smoothing and determining the accuracy of arrival angle calculations to prevent erroneous vehicle detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If OFDM-type radio communication with multiple multiplexed sub-carrier waves is used, then communication quality and bandwidth efficiency are improved, but the ability to accurately calculate arrival angle is degraded
Solution Approach 1:
The patent segments the complex OFDM signal into individual sub-carrier wave groups, each centered around a specific frequency. By resolving the signal into these segmented components and selecting sub-carrier waves with identical frequencies across different carrier waves, the system can accurately calculate arrival angles despite the multiplexed nature of OFDM communication.
2Productivity
If multiple sub-carrier waves are multiplexed in OFDM type, then bandwidth utilization is improved, but the complexity of signal processing increases
Solution Approach 1:
The patent extracts and resolves the OFDM signal into distinct sub-carrier wave groups centered at different frequencies. This extraction process separates the multiplexed signals in the frequency domain, allowing for simplified processing of individual sub-carrier waves while maintaining the benefits of OFDM bandwidth utilization.
3Reliability
If arrival angle calculation is not performed accurately, then vehicle specification reliability is improved (fewer false positives), but communication efficiency decreases
Solution Approach 1:
The patent replaces traditional mechanical or simple electronic arrival angle detection methods with a sophisticated signal processing approach that operates in the frequency domain. By using spectral resolution and phase comparison of sub-carrier waves, the system achieves accurate arrival angle calculation without requiring complex physical antenna arrays or mechanical scanning systems.
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
The solution effectively detects arrival angles in OFDM-type radio communications, preventing erroneous vehicle detection and ensuring accurate charging processes by distinguishing between intended and unintended vehicle communications.
Implementation Method 1
a first carrier wave received by a first antenna and the second carrier wave received by a second antenna, the first carrier wave and the second carrier wave being carrier waves obtained by multiplexing the plurality of sub-carrier waves having frequencies different from each other
Implementation Method 2
a carrier wave resolving unit that resolves a partial signal, which is extracted from a single unit signal among a plurality of unit signals which constitute signals transmitted by a first carrier wave and a second carrier wave, into a sub-carrier wave group that is constituted by a plurality of sub-carrier waves
Implementation Method 3
an arrival angle calculation unit that calculates an arrival angle of the first carrier wave at the first antenna or an arrival angle of the second carrier wave at the second antenna on the basis of a geometric relationship between a phase difference between a first sub-carrier wave selected from a first sub-carrier wave group
Implementation Method 4
calculates an arrival angle... on the basis of a geometric relationship between a phase difference... and arrangement positions of the first antenna and the second antenna
Data Source
AI summary
A radio wave arrival angle detection device of the present invention extracts symbols and resolves the same into sub-carriers having various frequency components, for OFDM carrier waves received by a first antenna and a second antenna, respectively. The arrival angle of the carrier waves is calculated on the basis of the geometric relationship between a phase shift of the respective sub-carriers of the OFDM carrier waves received by the first antenna and the second antenna, and the arrangement of the first antenna and the second antenna.