Station-side apparatus and PON system
View Patent ↗An OLT, which is a station-side apparatus in a PON system, is connected to an ONU via an optical fiber. The OLT includes: an optical receiver which receives a burst signal from an ONU; a burst header detection unit which detects a certain delimiter pattern included in a received burst signal so as to establish synchronization of the burst signal; and a control unit which allows the burst header detection unit to perform detection of a delimiter pattern during a predicted reception period of a burst signal.
1. A station-side apparatus for a PON system connected to a subscriber-side apparatus via an optical fiber, the station-side apparatus comprising:
a receiving unit configured to receive a burst signal from the subscriber-side apparatus;
a detection unit configured to detect a predetermined synchronization pattern included in the received burst signal so as to establish synchronization of the burst signal; and
a control unit configured to allow the detection unit to perform detection of a synchronization pattern during a predicted reception period of a burst signal,
wherein the control unit allows the detection unit to perform detection of a synchronization pattern during a discovery period for which a registration request frame from an unregistered subscriber-side apparatus is accepted, and
wherein, in response to a receive error in which the synchronization pattern does not match a fixed pattern occurring within the discovery period, the control unit sets discovery periods subsequent to the receive error shorter than discovery periods before the receive error.
2. The station-side apparatus of claim 1 , further comprising a dynamic bandwidth allocating unit configured to control a transmission start time and a transmission amount of a burst signal from the subscriber-side apparatus and to retain distance information with regard to a distance between the station-side apparatus and the subscriber-side apparatus, wherein
the control unit predicts the reception period of a burst signal on a basis of pieces of information with regard to the transmission start time, the transmission amount, and the distance acquired from the dynamic bandwidth allocating unit.
3. The station-side apparatus of claim 1 , wherein:
the receiving unit is configured to receive a burst signal transmitted at a first transmission rate and a burst signal transmitted at a second transmission rate and to switch an output destination of a burst signal in accordance with the transmission rate thereof;
the detection unit comprises a first detection unit configured to detect a synchronization pattern included in a burst signal transmitted at the first transmission rate, and a second detection unit configured to detect a synchronization pattern included in a burst signal transmitted at the second transmission rate; and
the control unit allows the first detection unit to perform detection of a synchronization pattern during a predicted reception period of a burst signal transmitted at the first transmission rate and also allows the second detection unit to perform detection of a synchronization pattern during a predicted reception period of a burst signal transmitted at the second transmission rate.
4. A PON system, comprising:
the station-side apparatus of claim 1 ; and
a subscriber-side apparatus connected to the station-side apparatus via an optical fiber.