Feedback Overhead in the FDD Downlink Massive MIMO System

One of the fundamental problems in massive multiple input output (MMIMO) systems based on frequency division duplexing (FDD) mode is acquisition channel state information at base station (BS). Indeed, these systems, reciprocity uplink (UL) and downlink (DL) channels not applicable. Thus, users are supposed, after having estimated their subchannels, to feedback them BS. Since size be returned proportional number antennas that very large, then we witness an excess for each user. It therefore essential find a way reduce this quantity, which affects overall performance system. In article, propose two new MMIMO-OFDM-FDD-DL schemas Givens rotation quantization used 802.11ac standard amount The first fusion between (GR) arithmetic coding (AC) technique, second combination GR method universal compression Lempel Ziv Welch (LZW). proposed schemes named & AC LZW (with improvement proposal modified version (LZWM) LZWM) second, respectively, compared both can achieve ratio up 95% (or even 98%) 83%, considerably exceeding recent advanced techniques.