Multiuser Millimeter Wave Cloud Radio Access Networks With Hybrid Precoding

This paper investigates the performance of cloud radio access networks (CRANs) for a downlink multiuser millimeter wave (mmWave) system, where randomly distributed remote radio heads (RRHs) supported by a central baseband unit (BBU) communicate with multiple mobile equipment (MEs). The fronthaul and access link transmissions are implemented with mmWave frequency bands. The RRHs and MEs are modeled as independent poisson point processes. We characterize the outage probability, average latency, and throughput of this system under essential factors, such as blockages, RRH density, and path loss. Two specific ME association scenarios are considered: best channel participation (BCP) and nearest neighbor participation (NNP). We derived for both scenarios, closed-form expressions of outage probability in the noise-limited case, and upper and lower bounds of outage probability in the interference-limited case. Our results show blockages and path loss to have a positive effect of decreasing outage probability. Larger antenna arrays are shown to compensate for communication degradation (outage performance and latency) with higher RRH deployment, which can be considered a tradeoff between intercluster interference and RRH density. Finally, we show that for the ME association process, BCP is the most viable for mmWave CRAN systems due to its outperforming NNP.