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Task Group mc (TGmc) of the IEEE 802.11 Working Group, sometimes referred to as IEEE 802.11mc, was the third maintenance/revision group for the IEEE 802.11 WLAN standards. Purpose was to incorporate accumulated maintenance changes (editorial and technical corrections) into IEEE Std 802.11-2012, and roll up approved amendments into the standard.
The work by TGmc resulted in the publication of IEEE Std 802.11-2016 in 2016.
TGmc has ceased its operation. Maintenance/revision for IEEE Std 802.11-2016 is being handled by TGmd.
Following amendments were incorporated by TGmc on top of IEEE Std 802.11-2012:
- IEEE Std 802.11ae-2012
- IEEE Std 802.11aa-2012
- IEEE Std 802.11ad-2012
- IEEE Std 802.11ac-2013
- IEEE Std 802.11af-2013
Wi-Fi Round Trip Time
While it is not the main purpose of the maintenance/revision group, some features deemed not big enough to require a full Task Group within the IEEE 802.11 WG are sometimes added to the IEEE 802.11 standard via the maintenance/revision group.
The main feature added through TGmc is commonly known as Wi-Fi Round Trip Time (Wi-Fi RTT). It allows computing devices to measure the distance to nearby Wi-Fi access points (APs) and determine their indoor location with a precision of 1–2 metres using round-trip delay. The accuracy is better than estimations with trilateration based on received signal strength indication (RSSI).
With a single Wi-Fi access point, only a distance measurement is available. With three or more nearby APs, an app can trilaterate a device's location with an accuracy of one to two meters. Not all devices have the necessary hardware support yet for this feature.
With accurate indoor position awareness, apps can perform advanced automation based on where a device is in a building. For example, a smartphone user can have lights turn on when they enter a particular room by simply making voice commands since the device is location-aware (e.g. "turn on the lights in this room").
Wi-Fi Round-Trip-Time in Android Pie does not require that the phone connect to any Wi-Fi access points. Only the phone is used to determine distance, not the APs. This feature is also tied into the Android operating system's existing location system to preserve the user's privacy. Apps using round-trip delay time (RTT) need the location permission, and the device must have location-based services enabled at the system level.
- "IEEE 802.11, The Working Group Setting the Standards for Wireless LANs". Ieee802.org.
- "IEEE P802 - Task Group M Status". Ieee802.org.
- "IEEE P802.11 Wireless LANs" (DOC). Mentor.ieee.org. Retrieved 28 February 2019. CS1 maint: discouraged parameter (link)
- Online Courses - Anytime, Anywhere
- "Enhanced WiFi Ranging with Round Trip Time (RTT) Measurements". ion.org. Retrieved 2018-03-22. CS1 maint: discouraged parameter (link)
- DEPRECATED: Starting with Android P the WiFi RTT is part of the public API! This Android library works as proxy to the hidden android.net.wifi.RttManager-API. To work as wrapper this lib makes heav..
- android.net.wifi.rtt Documentation for Android preview