Vectorization of the Sphere Detection algorithm

In this paper we present concepts for vectorization of sphere detection algorithms based on regularization of depth first tree search algorithms. Due to data dependant control flow, these tree search algorithms exhibit a highly irregular structure not allowing an efficient collaborative detection of multiple received symbols in parallel. In order to enable parallel symbol processing, a transformation of the irregular tree search algorithm is proposed resulting in a novel regular algorithm structure. Based on this, a concept for a vectorized list sphere detector is introduced, employing a SIMD computational model. In addition to this, limiting effects of vector processing are studied, leading to concepts which ease these effects and enable the utilization of vectorization´s benefits.