Abstract: An underwater communication apparatus includes a light transmitting device to transmits a first communication light and a light receiving device to receive a second communication light. Further, a light identification device is used to detect a reference pattern in two dimensions, which is set on a node communication apparatus, to obtain a detection pattern. The light transmitting device and the light receiving device respectively corresponding to the light identification device are set at two relative locations. A power apparatus is used to drive the underwater communication apparatus. A control/monitor apparatus obtains the detection pattern from the light identification device and analyze a difference state between the reference pattern and the detection pattern. According to the difference state, it controls the power apparatus to move the underwater communication apparatus to a location for the detection pattern and the reference pattern being two dimensionally aligned.

Abstract: An optical network failure recovery method for a passive optical network is provided. The method includes steps of: obtaining at least one round-trip delay value according to an equalization delay value of at least one optical network unit with respect to an operating optical line terminal; sorting the round-trip delay values in an increasing order and obtaining a minimum round-trip delay value; obtaining at least one difference between the minimum round-trip delay value and the round-trip delay value of each of the optical network units; and adjusting a start time and a stop time in a bandwidth map for a ranging response message replied by each of the optical network units according to the at least one difference.

Abstract: An optical network failure recovery method for a passive optical network is provided. The method includes steps of: obtaining at least one round-trip delay value according to an equalization delay value of at least one optical network unit with respect to an operating optical line terminal; sorting the round-trip delay values in an increasing order and obtaining a minimum round-trip delay value; obtaining at least one difference between the minimum round-trip delay value and the round-trip delay value of each of the optical network units; and adjusting a start time and a stop time in a bandwidth map for a ranging response message replied by each of the optical network units according to the at least one difference.