Wake Application from Suspended state on Beacon Enter taking too long

Question

I have an application that monitors for iBeacons. When the application terminates from a suspended state and then enters a beacon region that it is monitoring for, it can sometimes take a very long time (sometimes up to 1 minute) for the application to wake up (call didEnterRegion or didExitRegion). Is there anything I can do about this? Here is the code I am using when the application enters the background

- (void)extendBackgroundRunningTime {
    if (_backgroundTask != UIBackgroundTaskInvalid) {
        // if we are in here, that means the background task is already running.
        // don't restart it.
        return;
    }
    // Attempt to extend background time by initializing a placeholder background thread
    __block Boolean self_terminate = YES;
    _backgroundTask = [[UIApplication sharedApplication] beginBackgroundTaskWithName:kBISBeaconManagerKeyBackgroundTask expirationHandler:^{
        // Background task expired, completion
        if (self_terminate) {
            NSLog(@"Application Terminated");
            [[UIApplication sharedApplication] endBackgroundTask:_backgroundTask];
            _backgroundTask = UIBackgroundTaskInvalid;
        }
    }];
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        // Background task started
    });
}

Answer 1

A few thoughts:

• The code shown in the question extends background beacon ranging time. It does not do anything to affect beacon monitoring (monitoring APIs are what provide didEnterRegion and didExitRegion callbacks).

• Monitoring response times can vary quite a bit. Best case scenario, didEnterRegion callbacks will fire within a second or two of the beacon being in range. The didExitRegion event is always delayed by an additional 30 seconds (that's how long iOS waits before deciding a beacon is no longer visible.)

• The best case scenario times are not met if all 30 Bluetooth hardware acceleration slots are taken . These slots are across all apps on the phone. If your app tries to monitor a beacon region when all slots are taken, detection times fall back to software backup cycles and can take 15 minutes .

See here for more info: http://developer.radiusnetworks.com/2014/03/12/ios7-1-background-detection-times.html

http://developer.radiusnetworks.com/2015/04/21/max-beacon-regions-ios.html