A system-level study on multi-user MIMO Transmission for dense FDD networks

The need for cell densification leads to inter-cell interference mitigation techniques known as coordinated multipoint (CoMP) transmission and reception. In this work, we start from the weighted sum-rate maximization problem by evaluating the capacity of the broadcast channel (BC). We employ non-linear dirty paper coding (DPC) on a cluster basis with additional co-channel interference (CCI) caused from surrounding base stations (BSs). These results characterize the capacity of the BC under cellular propagation conditions. Subsequent, we summarize multi-cell simulation results assuming linear precoding and non-ideal clustering as well as user grouping. For downlink pre-coding we compare the well-studied limited feedback assumption, zero-forcing (ZF) beamforming for joint transmission downlink CoMP and compare their resulting sum-rates with the derived BC capacity.