How to run game on background in Android

In Android Application.runinbackground is not work T.T

So I need to find alternative solution.

I searched for a while and One said using OnApplicationPause().

But I can not use it. I think When Application is on background, timescale becomes to zero. So I use Time.timescale = 0; in that method. but not works.

For my game is network game, I must solve this problem.

If you know the tips, Help me plz. T.T