MU-MIMO Downlink Transmission Strategy Based on the Distributed Antennas for 3GPP LTE-A

The multiple input multiple output (MIMO) technology and the distributed antenna system (DAS) have emerged as the promising candidates for the future mobile communications. In this paper, we observe the downlink (DL) transmission in a single-cell multi-user MIMO (MU-MIMO) system based on the distributed antennas for 3GPP Long Term Evolution-Advanced (LTE-A). It is found that the existing methods presented in 3GPP LTE discussion may deteriorate system throughput sharply due to the inaccurate channel information feedback from user equipment (UE). We propose a novel strategy including several methods for the MU-MIMO DL transmission in DAS. First, a UE-specific channel vector quantization method is proposed to enable the BS to acquire more accurate channel direction information (CDI). In addition, we develop a new method for the channel quality information (CQI) computation at the side of UE. The extensive simulation performed in the various scenarios discloses that the proposed strategy achieves the performance gain in terms of system throughput by 600% at most and 20% at least.