  Cellular networks are evolving towards dense deployment of small cells. This
in turn demands flexible and efficient backhauling solutions. A viable solution
that reuses the same spectrum is wireless backhaul where the Small Base Station
(SBS) acts as a relay. In this paper we consider a reference system that uses
wired backhaul and each Mobile Station (MS) in the small cell has its uplink
and downlink rates defined. The central question is: if we remove the wired
backhaul, how much extra power should the wireless backhaul use in order to
support the same uplink/downlink rates? We introduce the idea of
wireless-emulated wire (WEW), based on two-way relaying and network coding.
Furthermore, in a scenario where two SBSs are served simultaneously, WEW gives
rise to new communication strategies, partially inspired by the private/public
messages from the Han-Kobayashi scheme for interference channel. We formulate
and solve the associated optimization problems. The proposed approach provides
a convincing argument that two-way communication is the proper context to
design and optimize wireless backhauling solutions.
