Patent ID: 7443874

Claim:
A control system in a passive optical network including an optical line terminal and a plurality of optical network terminating units configured to transmit an upstream frame and a downstream frame to each other, the optical line terminal comprising: a receiving unit configured to receive an optical signal sent from each of the plurality of optical network terminating units; a generating unit configured to generate a maintenance signal concerning a mini slot signal corresponding to each of the plurality of optical network terminating units on the basis of a receiving state of the mini slot signal in the optical signal, wherein the maintenance signal includes at least one of an out-of-synchronization of the mini-slot signal, an error in phase of receiving the mini-slot signal, and an error in a block of the mini-slot signal, and the maintenance signal causes a transition in one of the plurality of optical network terminating units from a dynamic bandwidth operation state to a dynamic bandwidth waiting state; a dynamic bandwidth assignment controller configured to control bandwidth of a stream in the upstream frame from each of the plurality of optical network terminating units to the optical line terminal depending on the maintenance signal; an assigning unit configured to dynamically assign the bandwidth of the stream in the upstream frame for the optical network terminating units; and a reset unit configured to reset the maintenance signal by receiving an optical signal matched with a slot GRANT of the optical line terminal in a dynamic bandwidth assignment operation state.