An efficient CDI acquisition scheme facilitating large scale antenna systems

Large Scale Antenna Systems (LSAS) will play a key role in future 5G networks, which is very sensitive to channel state information (CSI). To ground the LSAS in reality, practical CSI acquisition design with limited overhead is tasked to engineers. In this paper, we focus on channel direction information (CDI) acquisition by feedback for LSAS (i.e. assuming no channel reciprocity). An efficient channel direction probing scheme, called as differential channel direction probing (DCDP), are conceived. Based on the analysis, we conclude that this approach can save the overhead for CDI acquisition while can preserve the flexibility of beamforming, which are crucial for realizing the potential of future large scale antenna systems.