Presence Detection via Multipath Wireless Signal Intermittent Monitoring
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Solution Overview
Problem
Existing presence detection systems face high power consumption and limited detection range, making them unsuitable for wide-area applications, especially when integrated into battery-powered devices like remote controls for home appliances.
Innovation Solution
A presence detection system that uses a transmitter to send multipath wireless signals and a receiver to intermittently detect changes in reception levels, switching to shorter intervals only when changes are detected, thereby reducing continuous reception and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the receiver constantly receives wireless signals to detect presence, then detection reliability is improved, but power consumption increases
Solution Approach 1:
The receiver performs presence detection at periodic intervals rather than continuously. The control unit switches between a first reception interval (longer period) for normal operation and a second reception interval (shorter period) when presence is detected, achieving both power savings and reliable detection
Solution Approach 2:
The reception interval is dynamically adjusted based on detection results. When presence is detected, the system transitions to a shorter interval for more frequent monitoring, and when absence is confirmed, it switches to a longer interval to reduce power consumption
2Measurement precision
If microwaves are used for presence detection, then detection precision is improved, but device complexity and cost increase
Solution Approach 1:
Instead of using specialized microwave transmission and reception equipment, the system copies the functionality using existing wireless communication equipment (such as Wi-Fi routers or wireless sensors) that are already present in the environment, thereby avoiding complex specialized hardware while maintaining detection capability
Solution Approach 2:
The system uses multipath wireless signals that propagate throughout the entire room, allowing a single receiver to detect presence anywhere in the space, making the system universally applicable without requiring directional equipment or multiple sensors
3Ease of manufacture
If infrared sensors are used for presence detection, then ease of manufacture is improved, but detection reliability deteriorates due to weak signal strength
Solution Approach 1:
The system uses wireless signals (such as Wi-Fi or other radio waves) as an intermediary to detect presence indirectly through multipath propagation patterns, avoiding the need for direct line-of-sight infrared detection and overcoming the weakness of infrared signals while maintaining ease of implementation
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
Enables efficient presence detection over a wide area while minimizing power consumption, allowing for easy integration into battery-powered devices and controlling home appliances based on presence information.
Implementation Method 1
a transmitter 1a that transmits multipath wireless signals
Implementation Method 2
a receiver 2a that detects the presence of a person by receiving the transmitted wireless signals
Data Source
AI summary
A presence detection system is equipped with a transmitter that transmits a multipath wireless signal and a receiver that detects the presence of a person by receiving the transmitted wireless signal, within a prescribed space. On the basis of the reception level for a wireless signal received intermittently at the beginning of a first interval, the receiver determines whether there has been a change in the present/absent state of a person. When it is determined that there has been a change in the present/absent state of a person, the receiver determines whether a person is present/absent on the basis of variation in the reception level for a wireless signal received at the beginning of a second interval, which is shorter than the first interval.