Abstract: In a system that transmits and receives data through a high-level relay in a mesh ad hoc wireless network including the high-level relay and ad hoc wireless nodes, an increase in data traffic to the high-level relay, and the ad hoc wireless nodes in proximity to the high-level relay, a reduction in use efficiency of a wireless bandwidth of the high-level relay and in the proximity to the high-level relay in association with the increase in the data traffic, and a reduction in the efficiency of an entire mesh ad hoc wireless network are prevented. In the mesh ad hoc wireless network having the high-level relay, and the ad hoc wireless nodes each having a smart meter function unit, meter reading information collection implemented by the high-level relay is delegated to the ad hoc wireless nodes from the high-level relay by one hop, and the use efficiency of the wireless bandwidth in proximity to the high-level relay is improved.

Abstract: An optical network system including an OLT and ONUs is provided that can prevent the loss of a multicast signal. When receiving an encryption key generation request from the OLT, the ONU generates an encryption key, and transmits the generated encryption key to the OLT. When receiving a notice of timing from the OLT, the ONU updates the encryption key of a belonging group. When receiving a report message from a STB through the ONU, the OLT analyzes the report message, stores a group that the STB belongs to as well as the ONU in a second table, and transmits the encryption key generation request to the ONU. When receiving the encryption key from the ONU, the OLT further stores the encryption key in the second table, and transmits to the ONU a notice of the timing in which the encryption key is valid.

Abstract: An optical network system including an OLT and ONUs is provided that can prevent the loss of a multicast signal. When receiving an encryption key generation request from the OLT, the ONU generates an encryption key, and transmits the generated encryption key to the OLT. When receiving a notice of timing from the OLT, the ONU updates the encryption key of a belonging group. When receiving a report message from a STB through the ONU, the OLT analyzes the report message, stores a group that the STB belongs to as well as the ONU in a second table, and transmits the encryption key generation request to the ONU. When receiving the encryption key from the ONU, the OLT further stores the encryption key in the second table, and transmits to the ONU a notice of the timing in which the encryption key is valid.