Coordinated beamforming access for interfering half-duplex relay networks

This work deals with a relay-assisted cellular network, where the downlink communication is carried out in two orthogonal phases. In the first-hop transmission, multiple evolved Node Bs (eNB) transmit in a coordinated way to multiple half-duplex Relay Nodes (RNs). In the second-hop transmission, each RN assists a single User Equipment (UE) without precise channel knowledge. In the first hop, we consider two multiple-intput multiple-output (MIMO) access schemes: Interference Alignment (IA) and block diagonalization zero-forcing (ZF-BD) precoders for which power and transmission time to RNs are optimally allocated. Cell capacity and outage rates are evaluated and benchmarked to the case where network-MIMO (N-MIMO) coordinated transmission in used in the first hop.