Computationally efficient lattice reduction for MIMO-OFDM systems

We propose a computationally efficient lattice reduction (LR) algorithm for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems in frequency-selective fading channels. In our proposed algorithm, we exploit the inherent feature of unimodular transformation matrix P that remains the same for frequency components which have relatively high amplitude correlation. We eliminate the redundant calculations by reducing brute-force LR iterations among adjacent subcarriers. We simulate the error performance and complexity of the proposed algorithm under various MIMO-OFDM system configurations. The results demonstrate that the proposed algorithm could significantly reduce the LR complexity by up to 90% multiplications and 99% divisions of brute-force LR while maintaining the system performance.