Performance of Massive-MIMO OFDM system with M-QAM Modulation based on LS Channel Estimation

Abstract

A Least Squares Channel Estimation (LSCE) method is designated for a Massive MIMO system combined with Orthogonal Frequency Division Multiplexing (OFDM) and higher order modulation technique. The performance of ZF and MMSE detectors is evaluated with $(Nt\times Nr)$ , (50 × 100) and (50 × 300) respectively antennas array, for various modulations techniques 16-QAM, 64-QAM, and 128-QAM, and for various OFDM sub-carriers 64, 256, 512 and 1024. The performance is determined in terms of Bit Error Rate (BER). Increasing the number of Bits/symbol provides an increase of BER both the ZF and MMSE detectors for an antennas array 50 × 100; Whereas increasing the number of OFDM sub-carriers provides a decreasing of BER. Combining 128-QAM modulation with 1024-sub-carriers and increase the receiver antennas array three times (i.e., 50 × 300), decreases more the BER both the ZF and MMSE detectors. Consequently the ZF and MMSE detectors provide a best BER so a best system performance.