Abstract: Implementation of block diagonalization (BD) pre-coding scheme and related multi-user scheduling in multi-user multiple input multiple output (MU-MIMO) system are investigated. By exploiting the subspace decomposition technique, we design the transmit pre-coder matrix to realize simultaneous communications with zero multi-user interference and multiple data streams between transmitter and multi-user. Analysis of the BD scheme is carried out. Based on the maximum sum-capacity criteria, a multi-user scheduling algorithm is proposed with the BD scheme. Its low complexity is shown. Simulations show that, with the BD pre-coding scheme, the achievable throughput of the system adopting the proposed user scheduling is approximately the same as that of the system taking the brute searching user scheduling, and directly validate the proposed user scheduling.

Key words: multi-user scheduling, pre-coding matrix, multiple input multiple output (MIMO), subspace decomposition