摘要:
A medium access control method is provided in which a control station transmits one specific frame to terminal stations, thereby arranging a schedule of a data transmission time of the control station and each of the terminal stations and allowing a time zone unused by a station for data transmission to be allocated to another station. The control station transmits a schedule frame having defined therein a time occupied by each of the terminal stations, thereby reducing overhead. Also, the completion of the preceding communication performed by another station is detected, thereby effectively using an idle time of a medium and improving transmission efficiency.
摘要:
A transmitting/receiving apparatus includes a packet construction section for dividing continuous data into a plurality of subpackets, and constructing a packet by concatenating the plurality of subpackets; a modulation transmission section for modulating the constructed packet, and transmitting the modulated packet to another apparatus; a training session execution section for checking channel conditions, when a predetermined condition is satisfied, and changing a modulation rule; and a subpacket transmission confirmation section for confirming whether or not a subpacket included in the transmitted packet is transmitted successfully to the transmission destination apparatus. If the modulation rule is changed by the training session execution section, the packet construction section reconstructs a new packet by concatenating a subpacket, which is confirmed as an unsuccessfully-transmitted subpacket, with subpackets newly generated from the continuous data, and the modulation transmission section modulates the reconstructed new packet, and transmits the modulated packet.
摘要:
A medium access control method is provided in which a control station transmits one specific frame to terminal stations, thereby arranging a schedule of a data transmission time of the control station and each of the terminal stations and allowing a time zone unused by a station for data transmission to be allocated to another station. The control station transmits a schedule frame having defined therein a time occupied by each of the terminal stations, thereby reducing overhead. Also, the completion of the preceding communication performed by another station is detected, thereby effectively using an idle time of a medium and improving transmission efficiency.
摘要:
A communication terminal device of the present invention includes: a packet classification section 103 for classifying the packets by stream types and destinations; a packet accumulation section 104-107 for accumulating the packets classified by the packet classification section, so as to be separately stored based on classification by the stream types and the destinations; a QoS control section 113 for determining a transmission start requirement based on a QoS parameter which defines a transmission quality of a stream; a transmission control section 108 for determining whether the transmission start requirement is satisfied; a framing section 109 for generating the frame by concatenating the packets accumulated in the packet accumulation section if it is determined by the transmission control section that the transmission start requirement is satisfied; and a transmission section 110 for transmitting the frame generated by the framing section to a destination communication terminal device.
摘要:
A communication terminal device of the present invention includes: a packet classification section 103 for classifying the packets by stream types and destinations; a packet accumulation section 104-107 for accumulating the packets classified by the packet classification section, so as to be separately stored based on classification by the stream types and the destinations; a QoS control section 113 for determining a transmission start requirement based on a QoS parameter which defines a transmission quality of a stream; a transmission control section 108 for determining whether the transmission start requirement is satisfied; a framing section 109 for generating the frame by concatenating the packets accumulated in the packet accumulation section if it is determined by the transmission control section that the transmission start requirement is satisfied; and a transmission section 110 for transmitting the frame generated by the framing section to a destination communication terminal device.
摘要:
A communication terminal device of the present invention includes: a packet classification section 103 for classifying the packets by stream types and destinations; a packet accumulation section 104–107 for accumulating the packets classified by the packet classification section, so as to be separately stored based on classification by the stream types and the destinations; a QoS control section 113 for determining a transmission start requirement based on a QoS parameter which defines a transmission quality of a stream; a transmission control section 108 for determining whether the transmission start requirement is satisfied; a framing section 109 for generating the frame by concatenating the packets accumulated in the packet accumulation section if it is determined by the transmission control section that the transmission start requirement is satisfied; and a transmission section 110 for transmitting the frame generated by the framing section to a destination communication terminal device.
摘要:
A communication system includes communication protocols that allow a single network or multiple neighboring networks to increase resource sharing and reduce mutual interference and increase their overall throughput. Various protocols apply to homogenous networks in which all power line communication (PLC) devices of multiple networks are interoperable with respect to full power line communication in a common PHY (specifications, signaling capabilities, modulation scheme, coding scheme, bandwidth, etc.) and to heterogeneous networks in which devices of some PLC networks are not interoperable with PLC devices of other PLC networks with respect to full power line communication given that the devices of the different networks do not employ a common PHY. With respect to heterogeneous networks, a protocol is provided to enable coexistence via a signaling scheme common to all of the devices of the network that allows resource sharing between the devices of the multiple heterogeneous networks. Homogeneous networks are those in which all nodes can communicate with each other using a common PHY, so that information about one PLC network can be transferred to another PLC network. Heterogeneous networks are those in which not all PLC networks can exchange information using their own native PHY, such as where users in different apartments or houses use different devices having different specifications, different signaling capabilities, modulation scheme, coding scheme, bandwidth and the like.
摘要:
A highly efficient retransmission control method is achieved by preventing the order of data from being changed by one revolution of a modulo without adding extra overhead. The transmitting side continues to continuously transmit frames assigned frame numbers circulating by a modulo M to the receiving side. Upon detecting an error in the received frame, the receiving side returns a reject provided with the frame number of the frame. The transmitting side retransmits the frame to the receiving side in response to the reject. In a case where such retransmission control is carried out, the maximum number of times Nr a reject of the same frame is returnable is previously determined. The receiving side discontinues the return of the reject of the same frame until the number of times of the return exceeds the maximum number of times Nr. Consequently, the return of the reject of the same frame can be discontinued before the modulo of the frame number revolves once. As a result, it is possible to prevent the order of data from being changed by one revolution of the modulo.
摘要:
According to the picture data coding apparatus of the present invention, the picture data storage unit stores each frame inputted from the pre-process unit, and the frame memory stores the latest-transmitted decoded frame. The frame selection unit judges whether or not a frame under transmission can be displayed. If the frame has been judged to be incapable of being displayed, the frame selection unit judges whether or not each frame stored in the picture data storage unit 103 can be displayed or not, and selects the smallest numbered frame among frames which have been judged to be capable of being displayed. The coding unit predictive codes the selected frame by using the latest-transmitted frame stored in the frame memory 131 as a reference frame, thereby outputting it to the transmission buffer 127. These features can minimize frame skipping even when a frame under transmission becomes incapable of being displayed due to a burst error.
摘要:
The present invention includes an electric wire laid in cars, a PLC modem connected with each electric wire and a terminal connected with each PLC modem. The terminal can communicate through the electric wire by using the PLC modem. When the cars are coupled with each other, the electric wires are electrically connected with each other and a new address is allocated to a control unit which has a unique address provided for each terminal.