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 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 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 first communication device stores a transmission rate table including response times, and transmission rates associated with the response times, each first response time indicating a time for transmitting test data between the first and second communication devices, while transmitting load data between any pair of communication devices at one of different transmission rates. The first communication device determine a necessary transmission rate for actual data; detect a response time indicating a time for transmitting the test data between the first and second communication devices; determine a transmission rate associated with the response time, as a used transmission rate, based on the transmission rate table; determine an effective remaining transmission rate based on a maximum transmission rate of the communication network and the used transmission rate; and start transmission of the actual data when the effective remaining transmission rate is higher than the necessary transmission rate.
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 controller receives first or second equipment identifier from a first wireless communication apparatus, by using one wireless communication circuit of the third and fourth wireless communication circuit. When the one wireless communication circuit is the fourth wireless communication circuit, the controller sets an encryption key information for wireless communications with the first wireless communication apparatus, to encryption key information including an equipment identifier that does not coincide with a received equipment identifier among the received plurality of encryption key information, and controls the third wireless communication circuit to transmit and receive encrypted transmission data to and from the first wireless communication apparatus by using key data included in set encryption key information.
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 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 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.