Abstract— A continuously increasing demand for higher spectral efficiencies in mobile communications will require next generation cellular systems to employ a very dense reuse of spectrum in combination with smart interference mitigation or cancellation schemes. Recent publications have revealed a large potential in terms of spectral efficiency and system fairness of multi-cell cooperative schemes, where e.g. multiple base stations jointly receive or transmit signals connected to multiple terminals. The downside of these schemes is typically the large extent of backhaul link capacity required between base stations. In this paper, we focus on the cellular uplink and investigate the information theoretical limits of multi-cell cooperation under a constrained backhaul. We propose a framework that allows to observe different forms of cooperation between base stations in combination with superposition coding, revealing non-negligible performance improvements compared to our previous res...