根据苹果开发者文档技术问答。

**我的应用程序在后台运行时，我可以使用iOS设备发布iBeacon广告吗？**答：不可以。对于要发布iBeacon广告的iOS设备，请求此功能的应用程序必须位于最前面，屏幕已打开且设备已解锁。

参考-https://developer.apple.com/ibeacon/Getting-Started-with-iBeacon.pdf
我发现了这篇文章，它提供了一些细节，以连接BLE在后台的一些特定情况。https://medium.com/@cbartel/ios-scan-and-connect-to-a-ble-peripheral-in-the-background-731f960d520d

从CBCentralManager：

/**
 *  @method scanForPeripheralsWithServices:options:
 *
 *  @param serviceUUIDs A list of <code>CBUUID</code> objects representing the service(s) to scan for.
 *  @param options      An optional dictionary specifying options for the scan.
 *
 *  @discussion         Starts scanning for peripherals that are advertising any of the services listed in <i>serviceUUIDs</i>. Although strongly discouraged,
 *                      if <i>serviceUUIDs</i> is <i>nil</i> all discovered peripherals will be returned. If the central is already scanning with different
 *                      <i>serviceUUIDs</i> or <i>options</i>, the provided parameters will replace them.
 *                      Applications that have specified the <code>bluetooth-central</code> background mode are allowed to scan while backgrounded, with two
 *                      caveats: the scan must specify one or more service types in <i>serviceUUIDs</i>, and the <code>CBCentralManagerScanOptionAllowDuplicatesKey</code>
 *                      scan option will be ignored.
 *
 *  @see                centralManager:didDiscoverPeripheral:advertisementData:RSSI:
 *  @seealso            CBCentralManagerScanOptionAllowDuplicatesKey
 *  @seealso            CBCentralManagerScanOptionSolicitedServiceUUIDsKey
 *
 */
open func scanForPeripherals(withServices serviceUUIDs: [CBUUID]?, options: [String : Any]? = nil)

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这里重要的是Applications that have specified the bluetooth-central background mode are allowed to scan while backgrounded, with two caveats (...)
@huggie，你有什么成就吗？