如何在PHP Code Igniter中进行任务调度

I am developing android application in which I am using push notifications using app server developed in php, It is working fine, But I want to schedule notifications to send to devices, I am new to PHP and don't know how to schedule some event using PHP. While searching for this problem I got to know that it can be done using cron jobs, but I am not understanding how to do it. Please help me.

I would add to @rawatHemant that you can force a Controller's method to be invoked via console:

public function index()
{
    if($this->input->is_cli_request() == false)
    {
        echo "This script only runs from command line." . PHP_EOL;
        exit();
    }
}