Hot topic

TLDR

Wireless networks broadcast signals that can reach multiple nodes, but this feature is usually treated as interference; resolving these issues could revolutionize ad hoc networking. The paper aims to show how physical‑layer network coding can turn the broadcast property into a capacity‑boosting advantage in wireless ad hoc networks. The authors propose a physical‑layer network coding scheme that exploits the additive nature of simultaneously arriving EM waves to perform coding operations at the physical layer, unlike conventional post‑reception bit‑stream coding. Physical‑layer network coding achieves higher capacity than conventional network coding, represents the first EM‑wave based approach, and opens a new research area with implications for physical, MAC, and network layers.

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). The goal of this paper is to show how 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. PNC can yield higher capacity than straight-forward network coding when applied to wireless networks. We believe this is a first paper that ventures into EM-wave-based network coding at the physical layer and demonstrates its potential for boosting network capacity. PNC opens up a whole new research area because of its implications and new design requirements for the physical, MAC, and network layers of ad hoc wireless stations. The resolution of the many outstanding but interesting issues in PNC may lead to a revolutionary new paradigm for wireless ad hoc networking.