title: iOS BLE peripheral / advertisement data in background mode
body: <p>I'm developing a system which has a BLE device (TI CC2540) as Central and an iOS app on iPhone4S as Peripheral. Everything works fine except 1 function I need: white-list (filtering) advertising devices from central side.</p>
  
  <p>As far as I know, iOS devices use Random Resolvable MAC address, so we cannot apply white-list based on MAC address.</p>
  
  <p>So my current method is: put an ID on "Local name" field on advertisement data of iOS app (iOS device acts as peripheral), Central device will scan and filter based on retrieved advertisement data. This works unless app is in background.</p>
  
  <p>When my app is put in background, advertisement data is truncated and my "local name" does not appear over-the-air. From header file of corebluetooth, I see there is only "overflow area" data can be in advertisement data when app is in background, but only iOS device can read this area.</p>
  
  <p>So can anybody here light me how to add custom data into advertisement packet even in background mode, or any other solution to have this filtering function.</p>
  
  <p>Any comment will help me very much.</p>