Abstract: A communication system including: a base station; and a terminal configured to: select a known signal from at least one first known signal included in a plurality of known signals that is divided into the at least one first known signal and at least one second known signal, each of the at least one first known signal indicating that the terminal transmits a following uplink signal including a specific data, each of the at least one second known signal indicating that the terminal transmits the following uplink signal not including the specific data, the following uplink signal being transmitted from the terminal to the base station in association with the selected known signal, and transmit the selected known signal to the base station.

Abstract: A wireless communication system includes a machine to machine (M2M) device, and a base station that performs wireless communication with the M2M device. The M2M device includes a check-signal transmitting unit that transmits, after a bearer in a wireless section between itself and the base station is released, a check signal to the base station every first period by wireless communication using a frequency that is used in the bearer. The base station includes a determining unit and a notifying unit. The determining unit determines whether there is an abnormality in wireless connection between itself and the M2M device based on whether a check signal is received from the M2M device within a second period. The notifying unit notifies, when the determining unit determines that there is an abnormality in the wireless connection between itself and the M2M device, the abnormality to a predetermined notification destination.

Abstract: A communication system including: a base station; and a terminal configured to: select a known signal from at least one first known signal included in a plurality of known signals that is divided into the at least one first known signal and at least one second known signal, each of the at least one first known signal indicating that the terminal transmits a following uplink signal including a specific data, each of the at least one second known signal indicating that the terminal transmits the following uplink signal not including the specific data, the following uplink signal being transmitted from the terminal to the base station in association with the selected known signal, and transmit the selected known signal to the base station.

Abstract: In a communication apparatus performing data communication through a network having a relay apparatus which relays data, a data-path establishment unit establishes a data-communication path between the communication apparatus and an opposite end of the data-communication path, and a control-path establishment unit establishes a control-information path between the communication apparatus and an opposite end of the control-information path, where the control-information path is arranged for transmitting control information for controlling the data communication through the control-information path. In addition, an instruction transmission unit transmits an address-set instruction instructing the relay apparatus to search for a next-hop node in the data-communication path and store a MAC address of the next-hop node before the control-information path is established by the control-path establishment unit.

Abstract: In a communication apparatus performing data communication through a network having a relay apparatus which relays data, a data-path establishment unit establishes a data-communication path between the communication apparatus and an opposite end of the data-communication path, and a control-path establishment unit establishes a control-information path between the communication apparatus and an opposite end of the control-information path, where the control-information path is arranged for transmitting control information for controlling the data communication through the control-information path. In addition, an instruction transmission unit transmits an address-set instruction instructing the relay apparatus to search for a next-hop node in the data-communication path and store a MAC address of the next-hop node before the control-information path is established by the control-path establishment unit.

Abstract: The present invention provides novel polymorphic crystals (A) to (C) having excellent handling properties and an extremely low content of residual solvent of donepezil used as a precursor for production of donepezil hydrochloride having an excellent action as a medicament, and an industrial process for producing the same.