Conditional access system for digital multimedia broadcasting and method therefor

摘要

A digital multimedia broadcasting (DMB) conditional access system (CAS) for solving the difficulty in providing an adequate broadcasting signal by installing repeaters in shadow areas and restricting reception billing to only the subscribers in the shadow areas. The CAS includes first and second communication networks; a mobile terminal for reproducing a DMB signal; a repeater for scrambling a transport stream (TS) received from a DMB transmission tower and transmitting the scrambled TS to the mobile terminal; and a server for providing a key for the scrambling to the repeater through the first communication network and to the mobile terminal through the second communication network.