Method and system for communicating multimedia using reconfigurable rateless codes and decoding in-process status feedback

摘要

A method and system use capacity-approaching rateless code to communicate multimedia data even with very short codewords, such as 64 bits or less, via erasure and noise channels. The method provides a way to design the edge degree distribution of rateless codes for any arbitrary channel. Based on an equivalent metric of decoding behavior in any channels, the degree distribution of a rateless code such as Luby-transform codes and raptor codes is optimized based on in-process status of decoding. A regularized least-squares optimization is used to avoid erroneous decoding. Multiple feedbacks can further improve the performance.

主权项

1. A method communicating multimedia data from a transmitter to a receiver, comprising the steps:
encoding, in the transmitter, the multimedia data by a rateless encoder to produce encoded data using a degree distribution; transmitting the encoded data to the receiver via a channel, wherein the channel is subject to noise; decoding, in the receiver, an output of the channel by a decoder, wherein the decoder is a rateless decoder, and wherein the decoder is a random belief propagation decoder; transmitting, from the receiver to the transmitter, feedback of an in-process decoding status of the decoder at the receiver at an optimal feedback timing while receiving the encoded data; updating, in the transmitter, the degree distribution based on the feedback, such that the degree distribution varies over time; determining belief messages based on the decoder given the degree distribution; analyzing an entropy of the belief messages to determine an equivalent ripple size; optimizing the degree distribution having the equivalent ripple size using a regularized least-squares optimization; and iterating the steps of the determining the belief messages, analyzing the entropy and the optimizing until the degree distribution convergences to an optimal degree distribution.