iBeacon events while screen is off - ios

Question

I'm trying to trigger an event based on iBeacons
It works fine when the app is running in the foreground, background but not suspended (screen is turned off with power-button)
I can see the NSLog messages when on the lock screen, but not when the device screen is off.
Is there a way to do this?
AppDelegate.m:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
NSLog(#"applicationDidFinishLaunching");
_locationManager = [[CLLocationManager alloc] init];
_locationManager.delegate = self;
[_locationManager requestAlwaysAuthorization];
CLBeaconRegion *region;
region = [[CLBeaconRegion alloc] initWithProximityUUID:[[NSUUID alloc] initWithUUIDString:#"EBEFD083-70A2-47C8-9837-E7B5634DF524"] major: 9 minor: 103 identifier: #"region1"];
region.notifyEntryStateOnDisplay = YES;
region.notifyOnEntry = YES;
region.notifyOnExit = YES;
[_locationManager startMonitoringForRegion:region];
[_locationManager startRangingBeaconsInRegion:region];
return YES;
}
- (void)locationManager:(CLLocationManager *)manager didDetermineState:(CLRegionState)state forRegion:(CLRegion *)region
{
if(state == CLRegionStateInside) {
NSLog(#"locationManager didDetermineState INSIDE for %#", region.identifier);
}
else if(state == CLRegionStateOutside) {
NSLog(#"locationManager didDetermineState OUTSIDE for %#", region.identifier);
}
else {
NSLog(#"locationManager didDetermineState OTHER for %#", region.identifier);
}
}
- (void)locationManager:(CLLocationManager *)manager didRangeBeacons:(NSArray *)beacons inRegion:(CLBeaconRegion *)region
{
if ( beacons.count > 0 )
{
NSLog(#"locationManager didRangeBeacons: %#",beacons.description);
}
}
Info.plist (relevant section only):
<key>NSLocationAlwaysUsageDescription</key>
<string>app location requested</string>
<key>UIBackgroundModes</key>
<array>
<string>location</string>
<string>voip</string>
<string>bluetooth-peripheral</string>
<string>bluetooth-central</string>
<string>external-accessory</string>
</array>

Answer 1

Set pausesLocationUpdatesAutomatically property of LocationManager to "NO", With this property set to NO location services are never powered down. But you have to be careful, as setting this property to NO significantly increases the power usage of the device.

Answer 2

While beacon monitoring (didEnterRegion: and didExitRegion:) works in the background, beacon ranging (didRangeBeacons:inRegion:) only works when the app is in the foreground, and for a limited time in the background. These background limits include five seconds after the app is woken up into the background due to an event (like lock screen coming on due to your setting region.notifyEntryStateOnDisplay = YES;)
There are some tricks you can do to get extra background ranging time. Read here:
http://developer.radiusnetworks.com/2014/11/13/extending-background-ranging-on-ios.html