Build a simple android app for wireless paging from nearby devices

Please read the entire specs below and then respond or send your proposal. There are questions near the end of this project brief that you need to answer in your proposal. Proposals without any answer to the question will be rejected. For us to award the project to you, we need to know that you have understood the specs and can build the solution that we need. We need a wireless calling/paging system app with these features: We need an android app that can receive identifying data from nearby devices and cause an alarm buzzer to be triggered. User can see the id of the device that triggered the alarm. User should be able to set the ringtone of the alarm and also vibration if needed. The alarm should be triggered even if the phone and app are not in use and is locked. When the sending device sends the signal wirelessly (wifi or bluetooth) and continuously, the app user can snooze (for 2 minutes or variable) the buzzer alarm and attend to the device that had caused the alarm. When the user is attending to the device, he/she will switch the wireless signal off so that the signal that caused the alarm is no longer sending the signal. At this time the snoozed alarm should automatically be stopped and go away from the list of alarms that need attention. There will be about 50-100 devices in the range of the app user that can be switched on to send the signal whenever needed. more than one signal can be switched on and the app user should get to see a list of alarms and snoozed alarms on his/her app. There should be some initial registration module where the devices can be registered with particular app so that other nearby devices do not cause the alarm to be triggered on the app. There will be many other devices in the range and it is important that the device only causes alarm to be triggered on the app that it is registered with. There should be a feature to remove registration of a device form an app if the device is lost or replaced or if it is registered with another app later. Questions: On your proposal do mention which wireless technology is best suited for this application according to you: Bluetooth low energy or udp packet over Wifi? or any other tech? And why? How will you ensure that the app is not killed for memory management by android os? This app should also not be rejected by google play store because of background processing. Other information: We need a range of about 100-150 feet indoor. App should be widely supported on all android devices - even the older ones but we can limit to 4.3 and above if we are using ble. If wifi is used then do note that the ip of the app user is not known to the devices that are sending the signal and the devices are dumb devices that are set up to start or stop sending the signals with a switch.