Abstract: Provided is a communication system including multiple communication terminals, which are layered in a first layer, a second layer, and a third layer. The communication system includes at least two first communication terminals provided in the first layer. The communication system includes multiple second communication terminals provided in the second layer and capable of directly communicating with the first communication terminals. The communication system includes multiple third communication terminals provided in the third layer and capable of directly communicating with some of the second communication terminals. The second communication terminals and the third communication terminals are provided in multiple separate areas.

Abstract: A detection system for vehicle includes a reader and a first detector. The reader is provided in a vehicle, transmits and receives radio signals, and transmits transmission signals including at least radio signals for supplying electric power. The first detector is driven by the radio signals for supplying electric power included in the transmission signals when receiving the transmission signals and can transmit first response signals output in response to the transmission signals to the reader. The first detector is disposed in a sitting area on a seat where the first response signals transmitted to the reader are blocked. The reader determines a sitting state of a passenger based on whether the first response signals are received in response to the transmission signals.

Abstract: A wireless communication terminal in each node intercepts wireless communication among other nodes. When detecting failure in communication, the wireless communication terminal stores corresponding communication data on the node the wireless communication terminal belongs to, and relays the stored data by wireless communication. Transmission timing in each node is determined uniquely to the node, and data are transmitted periodically. In accordance with circumstances, the transmission timing in each node is changed to make the transmission timing in each data generation node earlier and to make the transmission timing in each data relay node later. Thus, a plurality of communication data are collected in data relay nodes. Each data relay node synthesizes a plurality of communication data, and performs relay transmission thereof.

Abstract: A detection system for vehicle includes a reader and a first detector. The reader is provided in a vehicle, transmits and receives radio signals, and transmits transmission signals including at least radio signals for supplying electric power. The first detector is driven by the radio signals for supplying electric power included in the transmission signals when receiving the transmission signals and can transmit first response signals output in response to the transmission signals to the reader. The first detector is disposed in a sitting area on a seat where the first response signals transmitted to the reader are blocked. The reader determines a sitting state of a passenger based on whether the first response signals are received in response to the transmission signals.

Abstract: A wireless communication terminal in each node intercepts wireless communication among other nodes. When detecting failure in communication, the wireless communication terminal stores corresponding communication data on the node the wireless communication terminal belongs to, and relays the stored data by wireless communication. Transmission timing in each node is determined uniquely to the node, and data are transmitted periodically. In accordance with circumstances, the transmission timing in each node is changed to make the transmission timing in each data generation node earlier and to make the transmission timing in each data relay node later. Thus, a plurality of communication data are collected in data relay nodes. Each data relay node synthesizes a plurality of communication data, and performs relay transmission thereof.