111 research outputs found
Band Codes for Energy-Efficient Network Coding with Application to P2P Mobile Streaming
A key problem in random network coding (NC) lies in the complexity and energy
consumption associated with the packet decoding processes, which hinder its
application in mobile environments. Controlling and hence limiting such factors
has always been an important but elusive research goal, since the packet degree
distribution, which is the main factor driving the complexity, is altered in a
non-deterministic way by the random recombinations at the network nodes. In
this paper we tackle this problem proposing Band Codes (BC), a novel class of
network codes specifically designed to preserve the packet degree distribution
during packet encoding, ecombination and decoding. BC are random codes over
GF(2) that exhibit low decoding complexity, feature limited and controlled
degree distribution by construction, and hence allow to effectively apply NC
even in energy-constrained scenarios. In particular, in this paper we motivate
and describe our new design and provide a thorough analysis of its performance.
We provide numerical simulations of the performance of BC in order to validate
the analysis and assess the overhead of BC with respect to a onventional NC
scheme. Moreover, peer-to-peer media streaming experiments with a random-push
protocol show that BC reduce the decoding complexity by a factor of two, to a
point where NC-based mobile streaming to mobile devices becomes practically
feasible.Comment: To be published in IEEE Transacions on Multimedi
Pollution-resilient peer-to-peer video streaming with Band Codes
Band Codes (BC) have been recently proposed as a solution for controlled-complexity random Network Coding (NC) in mobile applications, where energy consumption is a major concern. In this paper, we investigate the potential of BC in a peer-to-peer video streaming scenario where malicious and honest nodes coexists. Malicious nodes launch the so called pollution attack by randomly modifying the content of the coded packets they forward to downstream nodes, preventing honest nodes from correctly recovering the video stream. Whereas in much of the related literature this type of attack is addressed by identifying and isolating the malicious nodes, in this work we propose to address it by adaptively adjusting the coding scheme so to introduce resilience against pollution propagation. We experimentally show the impact of a pollution attack in a defenseless system and in a system where the coding parameters of BC are adaptively modulated following the discovery of polluted packets in the network. We observe that just by tuning the coding parameters, it is possible to reduce the impact of a pollution attack and restore the quality of the video communication
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