Mitsubishi Denki Kabushiki Kaisha

Kazuma Fukuda

Seiji Okumura

Norihito Takatori

A communication system, including: a transmitting terminal configured to transmit a plurality of data packets; and a receiving terminal configured to receive the plurality of data packets, wherein the receiving terminal is configured to calculate a first jitter moving average from a transmitting time and a receiving time of each packet received by the receiving terminal based on positive-valued jitter and negative-valued jitter, to calculate a second jitter moving average from the transmitting time and receiving time of each packet received by the receiving terminal based only on positive-valued jitter, and to send the first and the second jitter moving averages to the transmitting terminal, and the transmitting terminal is configured to predict an available bandwidth on a communication path between the transmitting terminal and the receiving terminal based on a comparison of the first and second jitter moving averages.

Communication system, transmission terminal and receiving terminal therefor

In a packet retransmitting system for retransmitting a packet including a sequence number in a packet header, which is lost during packet communication, a transmitting equipment () includes a priority degree information attaching unit () for defining a plurality of priority degrees, setting an importance degree of each of the plurality of priority degrees for a packet, producing priority degree information by using the plurality of priority degrees, and attaching the priority degree information to the packet header included in the packet repeatedly for each of the plurality of packets, a transmitter () for transmitting the plurality of packets, and a retransmitting unit () for receiving a retransmission request packet and retransmitting a packet of which retransmission is requested in the retransmission request packet received. A receiving equipment () includes a receiving unit () for receiving the plurality of packets and a retransmission requesting unit () for extracting a plurality of sequence numbers and a plurality of priority degree information from the packet header, detecting lost packets based on the plurality of sequence numbers and the plurality of priority degree information extracted, detecting an important packet among the lost packets, and requesting retransmission of the packet.

Packet retransmission system, packet transmission device, packet reception device, packet retransmission method, packet transmission method and packet reception method

In a communication system using a terminal connected to a packet network, the invention predicts a future communication state between terminals. This invention may also control congestion by delivering the packet according to the predicted future communication state. A receiving state monitor calculates a moving average of jitter and a packet loss rate based on a packet received by a packet receiver. A controller of a sending bit rate and an encoding rate obtains the moving average of jitter and the packet loss rate predicts a future communication state, and controls the sending bit rate and/or the encoding rate.

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Tokyo, Japan

Kazuma Fukuda