From connectivity to sensing: the birth of WiFi sensing

Traditionally, WiFi networks have focused on data transmission, enabling Internet connectivity in homes, offices and public spaces. However, in recent years an emerging field known as WiFi Sensing has emerged, which leverages wireless signals to detect events and changes in the environment. This approach is based on analyzing how signal strength, phase and other signal characteristics (such as Received Signal Strength Indicatoror CSI) are altered by the presence and movement of objects and people. In this way, the same communication infrastructures can simultaneously perform environmental monitoring and diagnostic functions without the need for additional specialized hardware.

The global WiFi Sensing market is expected to experience significant growth in the coming years, driven by factors such as increasing demand for smart home solutions, rising adoption of IoT devices, and continued advancements in WiFi sensing technology. Some of the most promising areas for commercialization include home security, internet service provider (ISP) integration, and smart home connectivity.

Innovative Applications of WiFi Signals

Health and Vitality Monitoring

One of the most surprising and advanced uses of WiFi signals is non-invasive monitoring of vital functions. Research such as UbiBreathe has shown that it is possible to estimate respiratory rate through subtle changes in the WiFi signal generated by chest movement during breathing. This method not only opens the door to telemedicine solutions for home care and elderly care but also offers the possibility of detecting episodes such as sleep apnea, with accuracy rates that in some studies have exceeded 96%.

In addition, other academic work has explored how WiFi Channel State Information (CSI) allows vital signs to be monitored remotely even in complex environments, offering an alternative to traditional medical devices while minimizing invasiveness and associated costs.

Security and Motion Detection

Leveraging WiFi signals to detect motion has become an increasingly valuable tool for home and commercial security. WiFi Sensing technology can complement traditional camera systems, offering advantages such as increased privacy (by not recording images) and simple installation. For example, certain algorithms analyze variations in signal attenuation to determine the presence or absence of people, detect intrusions or identify suspicious movements in specific areas. In conjunction with home automation solutions, these systems can trigger automatic actions such as turning on lights or activating alarms, optimizing the response to possible threats.

Asset Tracking and Tracing

Another emerging utility of WiFi signals is real-time location, also known as WiFi Tracking or RTLS (Real-Time Locating Systems). By analyzing signal strength and other parameters, it is possible to map the location of mobile devices or connected tags without the need for GPS. This technology is used in applications as diverse as asset tracking in large warehouses, people flow management in shopping malls, or even in logistics optimization within factories and hospitals. The ability to merge data from different sources - such as WiFi and even Bluetooth technology (iBeacon) - also makes it possible to create cross-media information systems that can personalize offers or alerts in real time.

Interaction and Gestures

The potential of WiFi signals is not limited to passive monitoring. Recent research has explored the use of WiFi for the recognition of specific gestures and movements, opening up new opportunities in the field of natural interfaces and human interaction. Using advanced signal processing algorithms, it is possible to distinguish between different types of gestures, making it possible to control devices or interact with systems intuitively. This type of application is in an exploratory phase but promises to seamlessly integrate communication and sensing into augmented reality, gaming and home automation applications.

Advantages and Challenges of these Technologies

Advantages

• Multifunctionality: With the same infrastructure, communication, health monitoring, security and location functions can be covered, optimizing resources and reducing costs.
• Non-invasive and Private: By not requiring invasive physical monitoring devices, the user's privacy remains intact, while valuable data is obtained to improve quality of life.
• Scalability: Thanks to the widespread adoption of WiFi and the flexibility of signal analysis, these systems can be easily integrated into homes, offices and industrial environments.

Problems

• Interference and Noise: WiFi signals can be affected by multiple sources of interference, which implies the need for sophisticated processing algorithms to filter out the noise and extract the relevant data.
• Data Privacy and Security: Although modern techniques allow the anonymization of information, it is crucial to implement robust security measures to protect sensitive data.
• Adaptation to Variable Environments: The implementation of these systems requires calibration for different environments (e.g., offices, homes or open spaces) to ensure consistent results in monitoring and detection.

Future of WiFi Sensing: Convergence with the Internet of Things

The integration of WiFi Sensing into the Internet of Things (IoT) represents a new paradigm where communication and sensing go hand in hand. With emerging standards such as IEEE 802.11bf, these technologies are expected to evolve into more accurate, reliable and accessible end-user applications. The convergence of functions - known in the technical field as Joint Communications and Sensing (JCAS) will enable everyday devices to fulfill multiple roles, making our homes, offices and even cities smarter, safer and more efficient.

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