iBeacon background ranging - swift

Question

I'm trying to set my application as a way to just start ranging in the background and get a notification when the user hit the shoulder button or home button(not all the time) and I don't want using background mode.
So I coded this in swift, it works when my app is working in background just for 10 seconds and ranging won't be restarted when the user re-enter or exit from region but I get callback for about 180 seconds which means my ranging will work for 3 minutes but it only send notification in its first 10 seconds.
I started a task in the background and then call my run function which will wake up init function. I'll be happy if someone shares its experience.
func applicationDidEnterBackground(_ application: UIApplication) {
// Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
// If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
BackgroundTask1.run(application:
application) { (BackgroundTask1_) in
}
run and init functions:
class func run(application: UIApplication, handler: (BackgroundTask1) -> ()) {
let backgroundTask = BackgroundTask1(application: application)
backgroundTask.begin()
handler(backgroundTask)
}
func init_()
{
let uuidString = "43F2ACD1-5522-4E0D-9E3F-4A828EA12C24"
let beaconRegionIdentifier = "Hello"
let beaconUUID:UUID = UUID(uuidString:uuidString)!
beaconRegion = CLBeaconRegion(proximityUUID: beaconUUID, identifier: beaconRegionIdentifier)
beaconRegion.notifyEntryStateOnDisplay = true
locationManager_ = CLLocationManager()
if (CLLocationManager.authorizationStatus() != CLAuthorizationStatus.authorizedWhenInUse) {
locationManager_!.requestWhenInUseAuthorization()
}
locationManager_?.allowsBackgroundLocationUpdates = true
locationManager_!.delegate = self
locationManager_!.pausesLocationUpdatesAutomatically=false
locationManager_?.startRangingBeacons(in: beaconRegion)
}
This is notificaion's code:
func locationManager(_ manager: CLLocationManager, didRangeBeacons beacons: [CLBeacon], in region: CLBeaconRegion) {
print("sdljflkj")
if beacons.count == 0 {
return
}
let currentbeacon = beacons[0]
lastproximity = currentbeacon.proximity
if currentbeacon.proximity == CLProximity.immediate{
DispatchQueue.global(qos: .userInitiated).async {
let content = UNMutableNotificationContent()
content.title = "Forget Me Not"
content.body = "Are you forgetting something?"
content.sound = .default()
let request = UNNotificationRequest(identifier: "ForgetMeNot", content: content, trigger: nil)
UNUserNotificationCenter.current().add(request, withCompletionHandler: nil)
print("here1")
NotificationCenter.default.post(name: Notification.Name(rawValue: "iBeaconFoundReceivedNotification"), object: nil, userInfo: ["Major":currentbeacon.major, "minor": currentbeacon.minor])
}
}
}