Efficient VLSI implementation of the list sphere decoder with real-value based tree searching method

In this paper, an efficient LSD architecture is proposed. This architecture uses real value based tree searching method and sorting algorithm. First, the LSD method in MIMO system is briefly introduced and the tree searching method for the LSD algorithm is analyzed. Secondary, the VLSI architecture of real value based tree searching method is proposed and compared with complex value based tree searching method. The proposed architecture has two main characteristics. The first one is that sorting operation makes the history pruning operation very simple. And the second one is that it requires very small HW resource usages compared with complex based method. Actually the total resource usages are about 20K equivalent NAND gates which is 1/3 for complex based method.