A New Fast Generalized Sphere Decoding Algorithm for Under-Determined MIMO Systems

Generalized sphere decoding (GSD) algorithms have been applied to decode the under-determined MIMO systems. It detects the transmitting vector by decoding a sequence of determined subproblems. In this paper a fast recursive GSD algorithm is proposed. This new algorithm can generate the sequence of determined subproblems in a more efficient way than the current algorithms. A column-reordering strategy for the channel matrix is incorporated into the reduction process of the new algorithm, which can significantly reduce the computational cost. Furthermore, a method to determine a good initial radius of the hyper-sphere is given. Numerical simulations show that the new recursive GSD algorithm can be significantly faster than the current algorithms