Massachusetts Institute of Technology

Daniel Lucani

Muriel Medard

Xiaomeng Shi

Minji Kim

Fang Zhao

Marie-Jose Montpetit

Milica Stojanovic

Marie-Joseph Montpetit

A method, apparatus and computer program product for utilizing network coding for multi-resolution multicast is presented. A network source partitions source content into a base layer and one or more refinement layers. The network source receives a respective one or more push-back messages from one or more network destination receivers, the push-back messages identifying the one or more refinement layers suited for each one of the one or more network destination receivers. The network source computes a network code involving the base layer and the one or more refinement layers for at least one of the one or more network destination receivers, and transmits the network code to the one or more network destination receivers in accordance with the push-back messages.

Network coding for multi-resolution multicast

A new random linear network coding scheme for reliable communications for time division duplexing channels is proposed. The setup assumes a packet erasure channel and that nodes cannot transmit and receive information simultaneously. The sender transmits coded data packets back-to-back before stopping to wait for the receiver to acknowledge (ACK) the number of degrees of freedom, if any, that are required to decode correctly the information. Provided herein is an analysis of this problem to show that there is an optimal number of coded data packets, in terms of mean completion time, to be sent before stopping to listen. This number depends on the latency, probabilities of packet erasure and ACK erasure, and the number of degrees of freedom that the receiver requires to decode the data. This scheme is optimal in terms of the mean time to complete the transmission of a fixed number of data packets. It is shown that its performance is very close to that of a full-duplex system, while transmitting a different number of coded packets can cause large degradation in performance, especially if latency is high. Also described herein is the throughput performance of the novel system and technique along with a comparison to existing half-duplex Go-back-N and Selective Repeat ARQ schemes. Numerical results, obtained for different latencies, show that the novel system and technique described herein has similar performance to the Selective Repeat in most cases and considerable performance gain when latency and packet error probability is high.

Random linear network coding for time division duplexing

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Cambridge, MA, United States of America

Daniel Lucani