Robust Wireless Network Coding – An Overview

Abstract

Abstract. Network Coding (NC) has witnessed a tremendous upsurge in interest and activities in recent years, both in academia and industry. Indeed, since the pioneering publication of Ahlswede et al. in 2000, NC has rapidly emerged as a major research area in information theory due to its wide applicability to communication through real networks. The many contributions available in the literature to date, ranging from purely theoretical studies on fundamental limits to practical experimentations in real-world environments, offer a clear evidence that the shift in paradigm envisaged by NC might revolutionize the way we manage, operate, and understand the organization of networks. However, the principle of NC is not without its limitations. Initial studies on NC were mainly focused on lossless channels, which, however, might have limited applicability to a wireless context. As a matter of fact, in practical wireless environments, NC might be very susceptible to transmission errors caused by noise, fading, or interference. In particular, the algebraic operations accomplished by the intermediate nodes of the network introduce some packet dependencies in a way that the injection of even a single erroneous packet has the potential to corrupt every packet received by the destination nodes. Motivated by this consideration, recent research efforts have been devoted to the design of robust NC, with the main goal to circumvent the critical limitations of the NC paradigm in practical operating environments. In this paper, we aim at providing an overview of the most important and notable research directions in this emerging field.

Flexible Network Codes Design for Cooperative Diversity

“…We consider a very simple implementation in which the relays demodulate-network-code-and-forward (D-NC-F) each received symbol without checking whether the symbol is correct or wrong. The main aim of this assumption is to keep the complexity of the relays at a very low level (Koetter & Kschischang, 2008), and to understand the robustness, in terms of coding and diversity gain, of the error propagation problem (Di Renzo et al, 2010a), (Di Renzo et al, 2010b) on various network codes.…”

Network Code Design from Unequal Error Protection Coding: Channel-Aware Receiver Design and Diversity Analysis

“…NC offers the promise of improved performance over state-of-the-art routing, and, in particular, it finds successful application in multi-hop/cooperative wireless networks [2], [3], as it offers an efficient way for boosting the achievable throughput (see [4], [5], and references therein).…”

Multiple-access relaying with network coding: iterative network/channel decoding with imperfect CSI

“…In this paper, we consider Rayleigh fading assumption for all links for convenience. In order to avoid mutual interference, we consider that transmissions are scheduled in time-orthogonal timeslots [4]. We study both perfect CSI and imperfect CSI at the receiver.…”

“…Recent results have shown that NC can also provide improved performance and energy efficiency compared with conventional network routing techniques [4]. However, besides the many potential advantages and applications of NC over classical routing, the NC principle is not without limitations.…”

“…Among the solutions that are currently being investigated to counteract the error propagation problem [4], joint network channel decoding (JNCD) is gaining a growing interest [7]. The idea behind JNCD is the exploitation of the inherent redundancy of network and channel codes.…”