AF relaying in a Massive MU-MIMO OFDM system

Due to the market demands, current communication systems evolve rapidly from existing 4G standard to a future 5G, that implies higher capacity and flexibility. In 4G systems the orthogonal frequency-division multiplexing (OFDM) modulation and multiple-input multiple-output (MIMO) technique are used to enable higher rates for mobile users, while in 5G it is expected to further increase the performances by using a significantly higher number of antennas (massive MIMO) and cooperative relays for solving the problem of coverage and capacity at the cell border. In this work, massive multiuser MIMO OFDM (MU-MIMO) systems, with 10 to 100 antennas are used, without relay nodes, to evaluate the bit error rate (BER) as a function of the Signal to Noise Ratio (SNR). Then, the system is further developed, by introducing amplify-and-forward (AF) relays as intermediaries between the transmitter and the receiver to see if the performances are improved.