Massive MIMO technology (MIMO technology with large number of antennas) is planned for use in 5G networks for significant capacity increasing. However, on the way of Massive MIMO application in 5G systems, there are many problems. Some problems are related to the development of digital signal processing algorithms with good quality characteristics and low computational complexity. In this paper Chebyshev linear and nonlinear iterative demodulation algorithms for MIMO systems are discussed along with Zero- Forcing (ZF) algorithm and minimum mean square error (MMSE) algorithm. For the comparison of these algorithms BER performance characteristics were obtained. The nonlinear algorithm shows a gain of about 1 dB compared to MMSE and has same computational complexity for the case of 64 antennas
