But it represents a “milestone,” he says, that could open new capabilities in water-air communications. The system, called “translational acoustic-RF communication” (TARF), is still in its early stages, Adib says. He co-authored the paper with his graduate student Francesco Tonolini.
Our idea is to transform the obstacle itself into a medium through which to communicate,” says Fadel Adib, an assistant professor in the Media Lab, who is leading this research. “Trying to cross the air-water boundary with wireless signals has been an obstacle. Above the surface, a highly sensitive receiver reads these minute disturbances and decodes the sonar signal. An underwater transmitter directs a sonar signal to the water’s surface, causing tiny vibrations that correspond to the 1s and 0s transmitted. In a paper being presented at this week’s SIGCOMM conference, MIT Media Lab researchers have designed a system that tackles this problem in a novel way. This causes inefficiencies and other issues for a variety of applications, such as ocean exploration and submarine-to-plane communication. Acoustic signals, or sonar, sent by underwater devices mostly reflect off the surface without ever breaking through. Radio signals that travel through air die very rapidly in water.
Today, underwater sensors cannot share data with those on land, as both use different wireless signals that only work in their respective mediums. Note:The FRITZ!Box displays wireless devices that support the standards 802.11k and 802.11v under "Wi-Fi > Wi-Fi Network > Known Wireless Devices" ("Wireless > Radio Network > Known Wireless LAN Devices") with the properties "11k" und "11v".MIT researchers have taken a step toward solving a longstanding challenge with wireless communication: direct data transmission between underwater and airborne devices. The FRITZ!Box cannot steer these devices to a different wireless access point.Īs soon as the 5 GHz Wi-Fi network is available again, the FRITZ!Box steers the wireless devices back to the 5 GHz network or a different wireless access point if necessary. The FRITZ!Box can only steer older wireless devices that do not support the wireless standards 802.11k and 802.11v from the 5 GHz to the 2.4 Wi-Fi network by briefly clearing the Wi-Fi connection.The FRITZ!Box can seamlessly steer wireless devices that support the wireless standards 802.11k and 802.11v from the 5 GHz to the 2.4 GHz Wi-Fi network or to a different wireless access point.To ensure that the Wi-Fi network can still be used even while the 5 GHz Wi-Fi network is disabled (DFS wait time), the FRITZ!Box steers the wireless devices to the 2.4 GHz Wi-Fi network or to a different wireless access point if necessary:
This behavior is also called Dynamic Frequency Selection (DFS) and is mandatory in all countries of the European Union. Then the FRITZ!Box notifies all of the Mesh Repeaters connected to it that there is a higher-priority user so that the FRITZ!Box and Mesh Repeaters can all disable the 5 GHz Wi-Fi network together and then re-enable it together after it has completed the search for higher-priority users. Mesh Repeaters connected to the FRITZ!Box notify the FRITZ!Box immediately if they detect a higher-priority user. If the FRITZ!Box detects one of these users, it disables the 5 GHz Wi-Fi network, searches again for higher-priority users for up to 10 minutes, and then re-enables the 5 GHz Wi-Fi network on a different Wi-Fi channel not used by them. The FRITZ!Box does not enable the 5 GHz Wi-Fi network until after completing the check (DFS wait time) that can take up to 10 minutes.Įven during operation, the FRITZ!Box continuously checks whether the Wi-Fi channels it uses are still unused by higher-priority users. In order not to disturb these higher-priority users, at first the FRITZ!Box only enables the 2.4 GHz Wi-Fi network after a restart or changes to the Wi-Fi settings. However, the 5 GHz frequency band is not only used by wireless devices, it is also used by radar systems (for example air traffic control, the military, and weather service), so-called higher-priority users. The FRITZ!Box makes the Wi-Fi network available in both the 2.4 GHz and 5 GHz frequency bands.
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