Implementation Aspects of List Sphere Detector Algorithms

A list sphere detector (LSD) can be used to approximate the optimal maximum a posteriori (MAP) detection. The total complexity of the LSD algorithms is relative to the number of visited nodes in the search tree. We compare the differences between real and complex signal model in the LSD algorithm implementation and study its impact on the complexity and performance with different search strategies. In hardware implementation, the number of visited nodes needs to be bounded in order to determine the complexity and the latency of the implementation. Thus, we study the performance of LSD algorithms with a limited number of nodes in the search. We show that the algorithms with real signal model are less complex compared to the complex signal model, and that the performance may suffer significantly with limited search depending on the search strategy.