DoF of Sectored Cellular Networks with C-RAN

This paper investigates the per user Degrees of Freedom (DoF) for uplink in sectored cellular networks which employ C-RAN architecture. The network consists of N base stations (BS) and K\leq N base band unit (BBU) pools. The communication between BSs and BBU pools occurs by means of finite-capacity fronthaul links. In the network, the computing units (BBU pools) have limited processing capacity. We propose a lower bound and cut-set bound on the per user DoF, where both of them are functions of processing capacity, the BBU pool/BS ratio r and fronthaul capacity. The achievability scheme is based on dividing the network into clusters, where some of the mobile users are silenced to provide isolation between them. It is shown, by simulations, that cut-set bound are attained for several cases and the achievability gap is very small for fronthaul capacity prelog μ F 2M, where M is the number of antennas at both transmitter and receiver.