Using Wireless Network Coding to Replace a Wired with Wireless Backhaul

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.