Fronthaul for 5G: low bit-rate design enabling joint transmission and reception

Centralization of base-band processing in mobile networks in a flexible manner is a key element of 5G architecture and aims to achieve significant performance and efficiency gains cite{rostcloud}. The increase of transmission bandwidth and of the number of antennas requires a modification of Cloud Radio Access Network (C-RAN) architecture in order to realize efficient and affordable data transfer between remote units (RUs) serving as distributed access points (APs) and the centralized processing unit (CU). In this paper we propose a dynamic placement of physical layer processing functions that decreases the data-rate on the fronthaul links between RUs and the CU while allowing multi-cell joint processing both on the downlink and on the uplink. We take into account various practical constraints such as latency and synchronization to evaluate the feasibility of our solution. A tradeoff between fronthaul data-rate and centralization allows to satisfy 5G requirements regarding latency, spectral efficiency and transmission rate.