Title :
ARQ for network coding
Author :
Sundararajan, Jay Kumar ; Shah, Devavrat ; Medard, Muriel
Author_Institution :
Lab. for Inf. & Decision Syst., Massachusetts Inst. of Technol., Cambridge, MA
Abstract :
A new coding and queue management algorithm is proposed for communication networks that employ linear network coding. The algorithm has the feature that the encoding process is truly online, as opposed to a block-by-block approach. The setup assumes a packet erasure broadcast channel with stochastic arrivals and full feedback, but the proposed scheme is potentially applicable to more general lossy networks with link-by-link feedback. The algorithm guarantees that the physical queue size at the sender tracks the backlog in degrees of freedom (also called the virtual queue size). The new notion of a node ldquoseeingrdquo a packet is introduced. In terms of this idea, our algorithm may be viewed as a natural extension of ARQ schemes to coded networks. Our approach, known as the drop-when-seen algorithm, is compared with a baseline queuing approach called drop-when-decoded. It is shown that the expected queue size for our approach is O[(1)/(1-rho)] as opposed to Omega[(1)/(1-rho)2] for the baseline approach, where rho is the load factor.
Keywords :
automatic repeat request; broadcast channels; channel coding; decoding; linear codes; queueing theory; stochastic processes; telecommunication network management; ARQ scheme; block-by-block approach; drop-when-decoded algorithm; drop-when-seen algorithm; encoding process; linear network coding algorithm; link-by-link feedback; packet erasure broadcast channel; queue management algorithm; stochastic arrival; Automatic repeat request; Broadcasting; Communication networks; Decoding; Delay; Feedback; Laboratories; Network coding; Telecommunication network reliability; Throughput;
Conference_Titel :
Information Theory, 2008. ISIT 2008. IEEE International Symposium on
Conference_Location :
Toronto, ON
Print_ISBN :
978-1-4244-2256-2
Electronic_ISBN :
978-1-4244-2257-9
DOI :
10.1109/ISIT.2008.4595268