Access Control via Channel Impulse Response Similarity
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Solution Overview
Problem
Access control systems in high-traffic buildings face challenges in efficiently distinguishing authorized from unauthorized users, especially in environments with dense pedestrian traffic where line of sight to the receiving device may be obstructed, leading to inefficiencies and potential security breaches.
Innovation Solution
An access control system utilizing a transmission and reception device for radio signals that determines a degree of similarity between channel impulse responses from a stationary and mobile device, allowing for accurate identification of authorized users without the need for direct line of sight, using WLAN/WiFi or ultra-wideband technology with a bandwidth of at least 500 MHz, and employing machine learning for enhanced accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional access control systems use line-of-sight radio communication, then device complexity is reduced, but reliability deteriorates in environments with obstructed line of sight
Solution Approach 1:
The patent replaces traditional line-of-sight radio communication with ultrasonic wave-based channel impulse response analysis. Instead of relying on direct electromagnetic wave paths, the system uses sound wave propagation characteristics (which can penetrate obstacles) to identify authorized users through unique acoustic fingerprints of their communication channel, thereby maintaining reliability without requiring clear visual or electromagnetic line of sight.
Solution Approach 2:
The patent introduces an intermediary acoustic channel analysis process between the transmitter and receiver. By measuring channel impulse responses through ultrasonic waves that can pass through walls and obstacles, the system creates an indirect identification method that doesn't require direct line of sight, thus resolving the contradiction between reliability in obstructed environments and system complexity.
2Measurement precision
If access control systems process detailed channel impulse responses to identify users, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent extracts only the essential characteristics from complex channel impulse responses - specifically focusing on time delay, signal strength, and spectral features - to create simplified user identification profiles. This extraction approach maintains high measurement precision for user identification while significantly reducing the computational complexity required for processing and comparing full channel impulse response data.
Solution Approach 2:
The patent transforms complex channel impulse response data into simplified parametric representations by identifying key parameters such as arrival time, signal amplitude, and frequency characteristics. This parameter transformation maintains the precision needed for accurate user identification while reducing the dimensional complexity of the data that must be processed and stored.
3Measurement precision
If the system uses broadband radio signals for access control, then measurement precision improves, but loss of energy increases
Solution Approach 1:
The patent substitutes electromagnetic radio signals with ultrasonic acoustic waves for channel impulse response measurement. Acoustic waves require significantly less energy to transmit while providing sufficient bandwidth for precise channel characterization. This substitution maintains measurement precision for user identification while dramatically reducing energy consumption compared to broadband radio signal transmission.
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 solution enables efficient and secure access control by accurately identifying users in high-density environments, reducing queuing and enhancing security by allowing authorized access while preventing unauthorized entry, even in situations without direct line of sight.
Implementation Method 1
a transmitter (4) for a radio signal (RF1), a receiver (14) for radio signals (RF1, RF2)
Data Source
Figure 1~2
Figure 3A~3F
Figure 4
AI summary
The invention relates to a system (1) for controlling access to a restricted-access zone (20) in a building, which system comprises a transmitting device (4) for transmitting a first radio signal (RF1), a receiving device (14) for radio signals (RF1, RF2), a control device (10, 11) and a signal-processing device (8), which is communicatively connected to the receiving device (14) and to the control device (10, 11). The signal-processing device (8) determines a first channel pulse response (h1(τ)) on the basis of a first radio signal (RF1) received by means of the receiving device (14) and a second channel pulse response (h2(τ)) on the basis of a second radio signal (RF2) received by means of the receiving device (14). The second radio signal (RF2) is transmitted by a first mobile electronic device (6) of a first user (2). The signal-processing device (8) also determines a degree of similarity by evaluating the first and second channel pulse responses (h1(τ), h2(τ)). The degree of similarity (SDS, SDA) indicates how similar the first and second channel pulse responses (h1(τ), h2(τ)) are to one another. The control device (10, 11) triggers a building action if, on the basis of the degree of similarity, a defined rule is satisfied.