On the Capacity Regions of Cloud Radio Access Networks With Limited Orthogonal Fronthaul

Uplink and downlink cloud radio access networks are modeled as two-hop ${K}$ -user ${L}$ -relay networks, whereby small base-stations act relays for end-to-end communications connected to a central processor via orthogonal fronthaul links of finite capacities. Simplified versions network compress–forward (or noisy coding) distributed decode–forward presented establish inner bounds on the capacity region uplink communications, that match respective cutset within gap independent channel gains signal noise ratios. These approximate regions then compared with no limit fronthaul. Although it takes infinite link capacities achieve these “fronthaul-unlimited” exactly, can be approached approximately finite-capacity The total required approach fronthaul-unlimited sum-rates (for downlink) characterized. Based results, scaling law in large size is established under certain models, both theoretically simulations.