Apparatus and method for reporting a power headroom in a wireless communication system

A method and apparatus for reporting a power headroom in a wireless communication system are given. A user device determines a power headroom based on a configured transmission power and transmits a power headroom report to a base station. The power headroom report comprising a Leistungsaussteuerungsreservepegel which indicates a power headroom, and a backoff indicator, which indicates whether the user device employing a power backoff due to power management.