Patent ID: 7502818
Filing Date: 2009-03-10
Classification: H04L,H04N

Abstract:
1. A data communications system for performing streaming data transmission, comprising: a data sender; and a data receiver, wherein the data sender includes, a packet sending processor for sending data packets containing data to be sent; a network status monitoring unit for monitoring the network status of a network between the data sender and the data receiver; a hierarchization unit for organizing encoded data to be sent into hierarchical layers; a data-sender-side controller for controlling an error control mode for the transmitted packets and a bit-rate by controlling the encoding mode of the hierarchization unit, based on the network status monitored by the network status monitoring unit and priority levels associated with the hierarchical layers generated by the hierarchization unit; a retransmission controller for extracting a data packet to be transmitted in accordance with a retransmission request message packet received from the data receiver; a prioritization processor for specifying priority levels for the hierarchical layers generated by the hierarchization unit based on an effect of loss during hierarchical encoding and a packet loss rate during transmitting, where a first hierarchical layer priority is set in an internet protocol (IP) header, and a second hierarchical layer priority is set in a realtime transport protocol (RTP) header; a forward error correction (FEC) processor for adding error-correcting redundant code to the encoded data, the encoded data outputted to an RTP packet generator; and wherein the data receiver includes, a packet reception processor for receiving the data packets from the data sender; a data-receiver-side network status monitoring unit for monitoring the network status; an error correction controller for detecting an error or packet loss in the data packets received from the data sender and performing error-compliant processing; a retransmission request controller for determining, on the basis of the detection of the error or packet loss in the data packets received from the data sender, whether to send the retransmission request message packet serving as a data packet retransmission request to the data sender; and a layer selection controller for selecting, in accordance with the hierarchy or priority, data to be processed on the basis of an analysis result by the data-receiver-side network status monitoring unit.