Abstract: In multi-user MIMO-OFDM communication systems， the increasing number of access users and transmitting/receiving antennas leads to severe multi-user interference and multi-stream interference. Therefore， a multi-user block diagonalization（BD）approach is employed to perform signal detection for multiple users on the same frequency band. An algorithm for continuous interference elimination based on BD and lattice reduction is proposed. Initially， the total channel for multiple users is decomposed into several mutually independent single-user subchannels using two singular value decomposition techniques. In theory， this step can completely eliminate multi-user interference. Subsequently， lattice reduction and QR sorting techniques are applied to optimize the decomposed channels， enhancing the orthogonality of the channel matrix while reducing computational complexity. Finally， a continuous interference elimination detection based on the minimum mean square error （MMSE） criterion is performed on the received signals at the receiver. This process systematically restores the original signals， eliminating multi-stream interference for each user. Simulation experiments demonstrate that the proposed algorithm significantly improves the detection performance of the communication system without increasing computational complexity. At a bit error rate of 10-3， the performance enhancement is 5.5 dB compared to traditional multi-user BD detection algorithms and around 4 dB compared to combined BD-based multi-user MMSE and zero-forcing （ZF） detection algorithms.

Key words:  , multi-input multi-output （MIMO）, orthogonal-frequency-division-multiplexing （OFDM）, lattice reduction （LR）, block diagonalization （BD）, successive interference cancellation （SIC）