Design of K-user massive MIMO networks

Network densification enables ultra high capacity gains in 5G networks by shrinking cell sizes, thereby bringing users closer to base stations. However, this leads to severe levels of interference. A promising method to suppress interference in K-user MIMO networks is interference alignment. Massive MIMO is another technology that is expected to contribute to increased capacity by the deployment of hundreds of transmit and receive antenna elements. In this paper we describe a design methodology for evolved 5G dense networks using interference alignment and K-user MIMO techniques. Our contributions include mathematical models showing the extension of the interference alignment protocol for K > 3 users using a modified hypercube network structure. We also provide a model for interference alignment under Cramér-Rao bound channel estimation error constraints. Further, we show how large numbers of transmit and receive antennas can provide additional signal power gains and present a user scheduling protocol to maximize capacity.