Abstract: A communication device includes: a distance information acquisition unit configured to acquire distance information indicating a distance to a communication target; a setting information acquisition unit configured to acquire setting information including a communication distance; and a communication unit configured to communicate with the communication target. The distance information acquisition unit acquires the distance information after the communication unit establishes connection with the communication target. The communication unit cuts the connection with the communication target when the distance information does not satisfy the communication distance included in the setting information.

Abstract: A communication device for performing wireless communication with another communication device, includes a wired communication interface configured to be connected to a wired communication line, a wireless communication interface configured to be connected to the other communication device by wireless communication, an antenna configured to transmit or receive a wireless signal related to the wireless communication, and a processor configured to, in a case that a destination of a first frame received by the wired communication interface indicates a broadcast address or a multicast address, wirelessly transmit a second frame to the other communication device with a modulation scheme and a coding rate set according to a wireless communication environment with the other communication device. The second frame includes the first frame and the second frame has a unicast address indicating a destination of the other communication device.

Abstract: A recording system according to the present disclosure includes a first host device, a first communication device connected to the first host device, a second host device, and a second communication device connected to the second host device. The second communication device is connected to a recording medium and wirelessly connected to the first communication device, and, when the recording medium is controlled to be writable between the second host device and the second communication device, the first communication device is configured to transmit information indicating that the recording medium is unwritable to the first host device.

Abstract: A wireless control device is provided with: a first wireless control unit that acquires first information including information indicating first positions of persons by using a first wireless method; a second wireless control unit that connects to wireless devices by using a second wireless method, and acquires second information that includes device identification information for identifying the wireless devices and information indicating second positions of the wireless devices; and an information control unit that selects the first position within a prescribed range from each second position, and specifies person identification information linked with the device identification information of the second position as the person identification information of a person present at the selected first position.

Abstract: A communication device for transmitting data to a plurality of radio terminals in radio communication includes: a first communication interface that performs radio communication with each of radio terminals in accordance with a first communication standard; and a controller that controls radio communication with each of the radio terminals, wherein the controller manages a modulation and coding scheme (MCS) level indicating a level of an MCS used for transmission of data for each of the radio terminals in association with a load amount indicating a communication load in the transmission of the data, wherein the controller, when detecting that the load amount is greater than a predetermined upper limit value, determines an allowable level of the MCS level corresponding to a load amount less than the upper limit value, and restricts the transmission of the data to use an MCS level equal to or higher than the allowable level.

Abstract: A train communication system is configured to perform wireless communication between two cars coupled to each other by using low power radio. The train communication system includes: a first device disposed on one coupling surface of two coupling surfaces facing each other between two cars; a second device disposed on the one coupling surface; a third device disposed on another coupling surface of the two coupling surfaces; and a fourth device disposed on the other coupling surface. The first device and the third device are disposed to face each other. The second device and the fourth device are disposed to face each other. When no wireless connections are established among the first device, the second device, the third device, and the fourth device, the first to fourth devices each perform at least one of switching of communication channels used for wireless communication among the first to fourth devices and switching of a master device or a slave device.

Abstract: A first antenna group includes one first antenna disposed at one end of a leading car, and another first antenna disposed at one end of a following car. A second antenna group includes one second antenna disposed at the one end of the leading car, the position where the one second antenna is disposed being different from the position where the one first antenna is disposed in a direction orthogonal to a travel direction of the leading car, and another second antenna disposed at the one end of the following car. A measurement unit measures radio wave strength between a pair of first antennas during communication via the first antenna group. A controller is enabled to make a switch from the first antenna group to the second antenna group when the radio wave strength is less than a predetermined value.

Abstract: A communication device for transmitting data to a plurality of radio terminals in radio communication includes: a first communication interface that performs radio communication with each of radio terminals in accordance with a first communication standard; and a controller that controls radio communication with each of the radio terminals, wherein the controller manages a modulation and coding scheme (MCS) level indicating a level of an MCS used for transmission of data for each of the radio terminals in association with a load amount indicating a communication load in the transmission of the data, wherein the controller, when detecting that the load amount is greater than a predetermined upper limit value, determines an allowable level of the MCS level corresponding to a load amount less than the upper limit value, and restricts the transmission of the data to use an MCS level equal to or higher than the allowable level.

Abstract: A recording system according to the present disclosure includes a first host device, a first communication device connected to the first host device, a second host device, and a second communication device connected to the second host device. The second communication device is connected to a recording medium and wirelessly connected to the first communication device, and, when the recording medium is controlled to be writable between the second host device and the second communication device, the first communication device is configured to transmit information indicating that the recording medium is unwritable to the first host device.

Abstract: An inter-vehicle communication system is a system that provides communication between vehicles with use of a beam having a directivity and includes a first antenna and a second antenna. The first antenna is provided to a first vehicle, and performs wireless communication. The second antenna is provided to a second vehicle coupled to the first vehicle, and performs wireless communication. The second antenna emits a beam toward the first antenna. In a state where the first vehicle and the second vehicle are aligned to each other, a position in a horizontal direction of the first antenna is different from a position in the horizontal direction of the second antenna.

Abstract: A communication system includes a transmission terminal and a reception terminal, and the transmission terminal transmits data to the reception terminal. The transmission terminal includes a storage unit that stores data and management information of the data, and a first communication unit that performs communication using a first radio method having non-directivity and a second radio method having directivity. The reception terminal includes a second communication unit that performs communication using the first radio method having non-directivity and the second radio method having directivity, and a selector that selects the data based on the management information. The first communication unit and the second communication unit communicate with each other using the first radio method having non-directivity when selecting the data to be transmitted, and communicates with each other using the second radio method having directivity when transmitting the selected data.

Abstract: A first wireless communication device includes: a first communication unit; and a first addition unit that adds first additional information to a connection signal. A second wireless communication device includes: a second communication unit; and a second addition unit that adds second additional information that differs from the first additional information to a connection request signal requesting connection with the first wireless communication device. The second communication unit transmits to the first wireless communication device the connection request signal with the second additional information added when the second communication unit receives from the first communication unit the connection signal with the first additional information added.

Abstract: A train communication system is configured to perform wireless communication between two cars coupled to each other by using low power radio. The train communication system includes: a first device disposed on one coupling surface of two coupling surfaces facing each other between two cars; a second device disposed on the one coupling surface; a third device disposed on another coupling surface of the two coupling surfaces; and a fourth device disposed on the other coupling surface. The first device and the third device are disposed to face each other. The second device and the fourth device are disposed to face each other. When no wireless connections are established among the first device, the second device, the third device, and the fourth device, the first to fourth devices each perform at least one of switching of communication channels used for wireless communication among the first to fourth devices and switching of a master device or a slave device.

Abstract: A first antenna group includes one first antenna disposed at one end of a leading car, and another first antenna disposed at one end of a following car. A second antenna group includes one second antenna disposed at the one end of the leading car, the position where the one second antenna is disposed being different from the position where the one first antenna is disposed in a direction orthogonal to a travel direction of the leading car, and another second antenna disposed at the one end of the following car. A measurement unit measures radio wave strength between a pair of first antennas during communication via the first antenna group. A controller is enabled to make a switch from the first antenna group to the second antenna group when the radio wave strength is less than a predetermined value.

Abstract: A communication system includes a transmission terminal and a reception terminal, and the transmission terminal transmits data to the reception terminal. The transmission terminal includes a storage unit that stores data and management information of the data, and a first communication unit that performs communication using a first radio method having non-directivity and a second radio method having directivity. The reception terminal includes a second communication unit that performs communication using the first radio method having non-directivity and the second radio method having directivity, and a selector that selects the data based on the management information. The first communication unit and the second communication unit communicate with each other using the first radio method having non-directivity when selecting the data to be transmitted, and communicates with each other using the second radio method having directivity when transmitting the selected data.

Abstract: A communication system includes a recording medium and a recording device that writes file data into the recording medium. The recording medium includes a storage that stores configuration information as management information about a file system of the recording medium, and a configuration information updating unit that updates the configuration information. The recording device includes an updating instruction unit that transmits an updating instruction for updating the configuration information based on the file data, to the recording medium, an acquisition unit that acquires the configuration information after transmission of the updating instruction, and a writing unit that writes the file data into the storage based on the configuration information acquired by the acquisition unit.

Abstract: A relay apparatus of the present disclosure is a relay apparatus which is connected to a host apparatus by a first communication method and to a terminal apparatus by a second communication method, and which transmits data to the terminal apparatus and receives data from the terminal apparatus in accordance with an instruction from the host apparatus, the relay apparatus including a communication quality measuring unit which extracts communication quality of the second communication method, a packet processor which detects an error in connection with the terminal apparatus, and an error transmission determining unit which changes timing of notifying the host apparatus of the error detected in the packet processor in accordance with the communication quality extracted in the communication quality measuring unit.

Abstract: A wireless communication apparatus uses a Wi-Fi system to transmit to another wireless communication apparatus a WiGig switching request frame (F1) requesting that the communication method for communicating with another wireless communication apparatus be switched from the Wi-Fi system to a WiGig system. The wireless communication apparatus uses RSSI when the WiGig switching request frame (F1) was received to determine whether to allow the switch from the Wi-Fi system to the WiGig system, and uses the Wi-Fi system to transmit to the wireless communication apparatus a WiGig switching response frame (F2) indicating the result of the determination.

Abstract: In a terminal having a plurality of wireless communication methods, an initiator terminal and a target terminal that efficiently execute a recovering process for transmitting data or receiving data if an error occurs are provided. An initiator terminal of the present disclosure includes a first wireless unit configured to connect with a target terminal via wireless communication with a first wireless communication method, a second wireless unit configured to connect with the target terminal via wireless communication with a second wireless communication method different from the first wireless communication method, and an access processor configured to execute an access protocol process for remote access to a storage medium that the target terminal includes.

Abstract: An access point terminal includes: a communication-terminal-status determination unit which determines a communication status of one wireless communication terminal out of wireless communication terminals, by obtaining a wireless signal transmitted or received by the one wireless communication terminal; and a frequency control unit which uses (i) a first frequency band for wireless communication with the one wireless communication terminal and (ii) a frequency band other than the first frequency band for the wireless communication with one or more of the wireless communication terminals other than the one wireless communication terminal, when the communication-terminal-status determination unit determines that the communication status of the one wireless communication terminal satisfies a predetermined condition.