SLNR based cascaded interference align precoding in CoMP

In this paper, an SLNR based cascaded interference align precoding algorithm is proposed according to the study on interference suppression in downlink coordinated multipoint transmission system. In this algorithm, cascaded precoding is adopted rather than delivering channel state information (CSI) among cells to deal with inter and inner cell interference stage by stage. In the first stage, interferences from different cells are aligned to the orthogonal space of receiving matrix of the expected cell, so that interference to the expected cell can be avoided. In the second stage, SLNR precoding is adopted to suppress the interferences among users within a cell. Simulation results indicate that the proposed algorithm improves the system capacity, reduces the bit error rate, and overcomes the limitation that the amount of online users within a cell.