摘要:
A multistage relay communication system 100 includes a trunk network 1 and branch networks 2 (2a, 2b), each of which includes one or more communication apparatuses 4. The communication apparatus 4 can switch between a trunk mode to operate in the trunk network 1 and a branch mode to operate in the branch network 2. In the trunk network 1, the communication apparatus 4 carries out fixing of a communication path and redundancy of data based on a path table in order to achieve real-timeness and a data arrival rate. Meanwhile, in the branch network 2, when a communication failure occurs, the communication apparatus 4 autonomously searches for a communication path and constructs a path table, in order to at least secure a data arrival rate even if real-timeness is impaired within an allowable range.
摘要:
A relay station comprises an emergency information detection unit for detecting an emergency information broadcasting flag in the digital broadcasting TMCC signal transmitted from the center station; a replacement data creation unit for issuing an instruction for creating replacement contents and replacing the data when emergency information is multiplexed in the TS; and a time synchronization unit for executing time synchronization between the TS created by the data replacement and the TS before the data replacement. On a receiving terminal, the replaced data broadcasting contents can be received while prefectural broadcasting video and audio contents are continuously received.
摘要:
In an advertising system where contents to be displayed are sent to display devices by digital broadcasting and the contents are displayed on sheet-shaped visual display units, when data update complete reply messages for confirming that specified advertisement has been displayed are communicated, channel congestion may arise due to simultaneous replies sent from a great number of information display devices. A display confirmation server is provided for confirming that information display has been updated on each information display device. Each information display device sends a reply message that display has updated to information received by digital broadcasting to the display confirmation server. At this time, each information display device waits for a randomly set wait time after changing information display before sending the reply. The display confirmation server that received the reply messages from the display devices reports data update complete on behalf of the display devices.
摘要:
Provided is a digital broadcast receiving device (20) which can display a high resolution image longer without burdening users with a cumbersome operation. The digital broadcast receiving device (20) of the present invention switches, based on vehicle information, between switching thresholds by which switching is made between plural digital broadcast decoders outputting different digital broadcast images from one another in accordance with a reception state of digital broadcast waves. The plural digital broadcast decoders include, for example, a stationary reception decoder (200), which outputs a digital broadcast image for stationary receivers, and a mobile reception decoder (201), which outputs a digital broadcast image for mobile receivers.
摘要:
In the digital broadcast to a mobile unit, the continuous reproduction of an image cannot be guaranteed when switching the hierarchical level in accordance with the receiving condition of the radio wave and therefore the viewer has a sense of discomfort. A digital broadcast sending apparatus sends out by encoding a plurality of simultaneous broadcast streams in the same sync signal generator. A switching determination unit of the receiving apparatus switches the plurality of simultaneous broadcast streams in accordance with the receiving condition (weak hierarchical level/strong hierarchical level), and a sync adjustment unit continuously displays an image without interruptions based on the received sync signal. At the time of this switching operation, one stream is gradually switched to the other.
摘要:
An electronic toll collection system (ETCS) for use in a tollgate for charging a car without the need for the car to stop, in which communication failures or errors due to reflected waves from a structure or a passing car are prevented. A roadside communication antenna which communicates with a vehicle-mounted communication antenna for charging, and a car sensor which detects a car (cars) in an area wider than a designed communication area are installed at the tollgate. As an electromagnetic wave path judgment section obtains data on the profile and position of a car which has entered the tollgate, from a car data detector, it calculates electromagnetic wave paths of direct and reflected waves which connect the roadside communication antenna 21 and the vehicle-mounted antenna in each of the cars, and calculates the receiving electric field strength for each of the paths. The direction of the path which has the highest field strength among the paths to the car in the communication area is selected as radiation direction and the direction of the other paths as radiation direction; then the directional pattern which makes the radiant intensity in radiation direction the maximum and that in radiation direction null is determined to control the radiation direction of the antenna unit through a directivity controller.
摘要:
The present invention provides a semiconductor light-emitting device including a first clad layer comprising a first conductive type of AlGaAsP compound, a second clad layer that is located next to the first clad layer, comprises a first conductive type of AlGaInP compound and has a thickness of up to 0.5 .mu.m, an active layer that is located next to the second clad layer and comprises a first or second conductive type AlGaInP or GaInP, a third clad layer that is located next to the active layer, comprises a second conductive type of AlGaInP compound and has a thickness of up to 0.5 .mu.m, and a fourth clad layer that is located next to the third clad layer and comprises a second conductive type of AlGaAsP compound, and/or a light-extracting layer that comprises a second conductive type AlGaP or GaP and has a thickness of 1 .mu.m to 100 .mu.m.
摘要:
A wireless communication system includes a wireless communication apparatus (fixed terminal) resided in a fixed station side providing a wireless antenna, a wireless communication unit, a server processing unit, a task list, a data communication unit, a buffer management unit and a buffer, and a wireless data transport apparatus (mobile terminal) resided in a mobile station side providing the wireless antenna, the wireless communication unit, a server determination unit, a task list I/O unit, the task list, a client processing unit and the buffer, thereby, the mobile terminal receives the task list from the fixed terminal to communicate data with another fixed terminal and transports not only the data but also a data acknowledgement, and the fixed terminal creates the acknowledgement to use the acknowledgement to thereby control a creation and deletion of bulk data appropriately.
摘要:
A radio propagation path from a transmitting point to a receiving point is estimated accurately with a relatively small amount of calculation. A predetermined-size receiving area including the receiving point is set, radio propagation paths from the transmitting point to the receiving area is estimated by a ray launching method, object surfaces existing in the paths are extracted, and a radio propagation path from the transmitting point to the receiving point is estimated by an imaging method using only the extracted object surfaces.
摘要:
A relay station comprises an emergency information detection unit for detecting an emergency information broadcasting flag in the digital broadcasting TMCC signal transmitted from the center station; a replacement data creation unit for issuing an instruction for creating replacement contents and replacing the data when emergency information is multiplexed in the TS; and a time synchronization unit for executing time synchronization between the TS created by the data replacement and the TS before the data replacement. On a receiving terminal, the replaced data broadcasting contents can be received while prefectural broadcasting video and audio contents are continuously received.