Dynamic Distributed Antenna Systems with Wireless mmWave Fronthaul

Cloud radio access network (CRAN) architectures promise improved scalability of mobile networks, both in terms of network capacity as well as capital expenditure for mobile network operators. Yet, the transition towards CRAN with fully virtualized base band units (BBUs) implemented in the cloud is a significant investment for network operators, since most of the existing base band processing hardware in already deployed macro base stations (BSs) becomes outdated. A gradual transition towards CRAN can be facilitated by initially reusing existing BBUs in macro BSs and augmenting them with additional remote radio units (RRUs), which are spatially distributed in the network coverage area and can be freely associated to any macro BS over reconfigurable fron-thaul connections. In this work, we consider wireless mmWave fronthaul links between BSs and RRUs that are dynamically established on-demand, to form so-called dynamic distributed antenna systems (dDAS), which support distributed MIMO transmission. This architecture stands in-between a fully virtualized CRAN architecture and conventional distributed antenna systems, in which fronthaul links are static. We consider optimization of the RRU allocation of the dDAS under realistic wireless fronthaul limitations.