先把收集到有用资料整理一下，等项目完成再写篇文章
app在后台播放报警音：https://developer.apple.com/library/ios/qa/qa1668/_index.html
后台运行设置：http://blog.shiqichan.com/ios-ble-background-central-scanning/
http://blog.csdn.net/monsterguaishou/article/details/36013659
蓝牙app后台运行接收数据、通知设定：http://blog.csdn.net/hitwhylz/article/details/28664939
http://stackoverflow.com/questions/19283488/how-do-i-enable-background-audio-for-an-iphone-app
http://stackoverflow.com/questions/19570211/avaudioplayer-doesnt-play-audio-in-iphone-5-when-locked
https://github.com/jsagorin/iOSBackgroundAudio
ble4.0 app后台运行、报警、通知实现,布布扣,bubuko.com
原文：http://blog.csdn.net/feixiang_song/article/details/38727977