  We present a diversity multiplexing tradeoff (DMT) optimal tree pruning
sphere decoding algorithm which visits merely a single branch of the search
tree of the sphere decoding (SD) algorithm, while maintaining the DMT
optimality at high signal to noise ratio (SNR) regime. The search tree of the
sphere decoding algorithm is pruned via intersecting one dimensional spheres
with the hypersphere of the SD algorithm, and the radii are chosen to guarantee
the DMT optimality. In contrast to the conventional DMT optimal SD algorithm,
which is known to have a polynomial complexity at high SNR regime, we show that
the proposed method achieves the DMT optimality by solely visiting a single
branch of the search tree at high SNR regime. The simulation results are
corroborated with the claimed characteristics of the algorithm in two different
scenarios.
