A novel approach for K-best MIMO detection and its VLSI implementation

Since the complexity of MIMO detection algorithms is exponential, the K-best algorithm is often chosen for efficient VLSI implementation. This detection problem is often viewed as a tree search problem where the breadth first search (BFS) method is adopted and only the K-best branches are kept at each level of the tree. An earlier VLSI implementation of the K-best BFS has been reported, however it has an inherent speed bottleneck due to the calculation of many path metrics and then sorting among them to select the K-best. In this paper an alternative implementation of the BFS is presented, which is suitable for VLSI implementation. To test the performance of this approach it has been applied to a 4X4 MIMO detector with a 64 QAM constellation. The results show less than 1 dB degradation from the sphere decoding algorithm. The implementation of a single spiral cell, the basic block behind the system, occupies a 764 mum² of area and consumes a 52.58 muw of power a 0.13 mum CMOS technology.