Patent ID: 8712242

Claim:
A method for ranging in a passive optical network, comprising: obtaining a Round Trip Delay (RTD) between an Optical Line Terminal (OLT) and an Optical Network Unit (ONU); and opening a quiet window used for the ranging for the ONU according to the RTD to perform the ranging on this ONU, wherein the step of opening the quiet window used for the ranging for the ONU according to the RTD to perform the ranging on this ONU comprises: determining a required period T during performing the ranging on the ONU according to the RTD; obtaining an open time of the quiet window according to the determined required period T during performing the ranging on the ONU and a preset adjustment time Δt; when the ONU is in a ranging state, sending a ranging request to the ONU, and opening the quiet window used for performing the ranging on the ONU simultaneously, wherein the quiet window includes the open time of the quiet window; receiving a ranging response within the open time of the quiet window; and obtaining an Equalization Delay (EqD) of the ONU that is in the ranging state and sending the EqD to the ONU that is in the ranging state.