Complexity analysis of a hybrid threshold-based ZF-MMSE equalizer for sic-based MIMO-OFDM receivers

In this paper, we propose a new reception scheme for MIMO-OFDM systems, which can switch between two different equalization methodologies, accordingly, on a subcarrier basis. In fact, the proposed receiver is based on the ordered successive interference cancellation (SIC) technique and uses jointly zero forcing SIC (ZF-SIC) and minimum mean squared error SIC (MMSE-SIC) according to a defined threshold value. The modulation scheme considered in this study is QPSK. Our main objective, here, is the provision of the computational complexity efficiency. Hence, a complexity analysis is provided and upper and lower complexity bounds for the proposed scheme are also derived.