I have already red many posts about the subject, some of these works, but only on some devices. For example it works on my Nexus 4, Nexus 5 with cyaogenmod, but not on my Xiaomi Mi2s (jelly beam 4.1.1)
I tried setting it sticky, using alarm, and broadcast receiver on destroy. But neither of them worked out. When I kill the application it never wake up again. But on the same device Whatsapp works perfectly, and even if I kill it, it wake up again..
Is there any way to do it without use GCM?
Some of the link I already looked up:
How to restart a killed service automatically?
Service that repeatedly runs a method, after an amount of time
I'm not sure if it will solve the issue for you or not but it worked for me.
I'm running MIUI 6.6.10
Open the Security app provided by Xiaomi
Click on permissions -> Autostart
Here allow your app to auto start
WhatsApp and all famous apps work because Xiaomi white listed them and allowed them to autostart.
来源：https://stackoverflow.com/questions/26615633/how-to-auto-restart-a-service-when-killed