Cost-Aware Fronthaul Rate Allocation to Maximize Benefit of Multi-User Reception in C-RAN

Aiming to throughput enhancement in future mobile networks, dense deployment of wireless access points (APs) is intended. Spectral efficiency on the uplink can be improved via joint processing of users located in areas covered by several APs. Thanks to centralized processing of such users enabled by Cloud Radio Access Network (C-RAN) architecture, low-latency multi-cell cooperation becomes possible. However, the price to pay to benefit from its advantages is the cost of transferring data from distributed access points to the data center through limited-capacity fronthaul links. A mobile network operator using C-RAN would have the objective to maximize data transmission rates with lowest possible fronthaul rate. We consider in this work the optimal tradeoff between the amount of fronthaul allocated and the sum rate of each user group in a multiple access scheme, where the wireless resource is reused among the user groups. By performing low-complexity joint reception of signals quantized according to attributed fronthaul rate, we can maximize the benefit of uplink transmission in C-RAN despite constrained fronthaul links. With optimal fronthaul allocation, the net benefit of the uplink transmission improves by 10% in a usual configuration.