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corona-warn-app / cwa-wishlist

Central repository to collect community feature requests and improvements. The CWA development ends on May 31, 2023. You still can warn other users until April 30, 2023. More information:
https://coronawarn.app/en/faq/#ramp_down
Apache License 2.0
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Adding Wi-Fi P2P support for nearby Android devices to detect each other #7

Open SeanXu1984 opened 4 years ago

SeanXu1984 commented 4 years ago

Feature description

In addition to Bluetooth Low Energy, Wi-Fi P2P should also be used to enable the communication between nearby Android devices which don't support Bluetooth Peripheral mode. Wi-Fi P2P is very well supported by Android 4+ I understand Google Exposure Notification APIs are used here but could you forward this request to Google?

Problem and motivation

Both Bluetooth Central mode and Bluetooth Peripheral mode need to be supported by the Android devices in order for the Google Exposure Notification APIs to work and it is said Bluetooth Peripheral mode is supported by Android 5+. But I believe there are still Android devices running Android 6+ that don't support Bluetooth Peripheral mode. (Depending on what kind of Bluetooth chipset is used and the manufacturer.)

Is this something you're interested in working on

Please forward this request to Google.

Internal Tracking ID: EXPOSUREAPP-2185

realansgar commented 4 years ago

For BLE extensive tests were made to make distance measuring work. Using a different wireless standard requires that process to be done all over again. I doubt that this feature will be adopted.

mohe2015 commented 4 years ago

Also Wifi probably uses WAY more power.

tens0rfl0w commented 4 years ago

Actually this is a nice idea, but please keep two things in mind: First, the interoperability with iOS devices needs to be provided at any point and because iOS has no API for Wifi Direct, this would be a one sided platform feature. The EN framework is developed together between Google and Apple, so it is not possible for Google to add platform specified features.

Secondly, you can track distances with Wi-Fi RTT (Round-Trip-Time), but this was introduced in Android 9 (API Level 28), so adoption is drastically lower than with BLE. I know that there is true range multilateration (RSSI) (which got implemented in API Level 1), but this is heavily inaccurate and not usable for fine distance measurements.

So there is practically no way of tracking a position between two devices precisely enough using the Wifi-protocol.

Please see the Wi-Fi Direct specification for usage of this protocol. If you are interested in the technical/physical barriers to make such feature possible, here is a great write-up that points out the problems of different attempts to enable such feature on the basic Wi-Fi protocol.

Ein-Tim commented 3 years ago

Should this be transferred to the Android repo as it is Android exclusive?