Wiegand, Till; Paul, Steffen (Institute of Electrodynamics and Microelectronics (ITEM), University of Bremen, Otto-Hahn-Allee, NW1, 28359, Bremen, Germany)
MIMO detectors are one of the most complex parts within a wireless communication system. In particular, for high throughput communication standards, like the 3GPP Long Term Evolution, reduced complexity detectors, which achieve a good BER performance are of major interest. Sphere decoder algorithms are one kind of tree search algorithms, which offer a good complexity-performance trade-off. In this paper we introduce a novel computation unit for a sphere decoder algorithm, which achieves an identical behavior compared to a complex sphere decoder, in terms of the BER performance and the number of visited nodes, by a reduced computational complexity. This is achieved due to calculating the Partial Euclidean Distance of the real and the imaginary part of a partial symbol vector totally independently from each other. For example, the number of adders is reduced by about 46% and the signal propagation delay is cut down by one adder stage for the computation unit. Furthermore, the comparator elements of the minimum unit are reduced by 60% and the signal propagation delay is cut down by two comparator stages.