Applying physical layer network coding in wireless networks

TL;DR

This paper introduces physical layer network coding (PNC) that exploits electromagnetic wave superposition to significantly increase throughput in wireless networks, transforming interference into an advantage.

Contribution

It proposes a novel PNC scheme that uses electromagnetic wave addition for coding, achieving substantial throughput gains over traditional methods in wireless ad hoc networks.

Findings

Potential 100% throughput increase over traditional transmission.

Achieves 50% throughput gain over straightforward network coding in 1-D networks.

200% throughput improvement in 2-D networks.

Abstract

A main distinguishing feature of a wireless network compared with a wired network is its broadcast nature, in which the signal transmitted by a node may reach several other nodes, and a node may receive signals from several other nodes, simultaneously. Rather than a blessing, this feature is treated more as an interference-inducing nuisance in most wireless networks today (e.g., IEEE 802.11). This paper shows that the concept of network coding can be applied at the physical layer to turn the broadcast property into a capacity-boosting advantage in wireless ad hoc networks. Specifically, we propose a physical-layer network coding (PNC) scheme to coordinate transmissions among nodes. In contrast to "straightforward" network coding which performs coding arithmetic on digital bit streams after they have been received, PNC makes use of the additive nature of simultaneously arriving electromagnetic (EM) waves for equivalent coding operation. And in doing so, PNC can potentially achieve 100% and 50% throughput increases compared with traditional transmission and straightforward network coding, respectively, in 1-D regular linear networks with multiple random flows. The throughput improvements are even larger in 2-D regular networks: 200% and 100%, respectively.