Power control for cellular networks with large antenna arrays and ubiquitous relaying

We consider a cellular network in which the base stations (BSs) are supported by a large amount of very low-complexity relays that are spread over the entire area, like a carpet. This carpet of relays enables massive antenna arrays and sophisticated multi-user MIMO transmission at the BSs, as they see only the static relays as the nodes they communicate with. On the other hand, the communication via the small relay cells allows to improve coverage and data rates by distributed signal processing. In order to control the residual interference caused by the massively deployed relay nodes, we apply power control to either minimize the transmit power at the BSs and relays required to achieve desired user rates, to maximize the minimum rate, or to minimize the outage probability. The proposed schemes are all of low complexity and show that the relay carpet is a promising concept for communication in future cellular networks.