Distributed Interference Mitigation: Communication vs Cooperation Tradeoff

In this work we consider an interference channel model in which K decentralized receivers cooperatively attempt to decode their intended messages locally by processing and sharing information through limited capacity backhaul links. In contrast to distributed antenna architectures that have been proposed in the literature (e.g., C-RAN, Network-MIMO), where data processing is utterly performed in a centralized fashion, the model considered in this paper tries to capture the essence of decentralized (over the cloud) processing in wireless networks, allowing for a more general class of interference mitigation strategies. Under this model, we aim to characterize the fundamental tradeoff between the achievable communication rates and the corresponding backhaul cooperation rate from a degrees of freedom (DoF) perspective. More specifically we derive an upper bound on the average (per user) achievable DoF as a function of the available (per user) backhaul capacity and propose an asymptotic alignment scheme for K = 3 based on lattice codes that is able to achieve the entire DoF-backhaul tradeoff.