On radius control of tree-pruned sphere decoding

In this paper, we propose a novel radius control strategy for sphere decoding referred to as inter search radius control that provides further improvement of the computational complexity with minimal extra cost and negligible performance penalty. The proposed method focuses on the sphere radius control strategy when a candidate lattice point is found. For this purpose, the dynamic radius update strategy as well as the lattice independent radius selection scheme are jointly exploited. From simulations in multiple-input and multiple-output (MIMO) channels, it is shown that the proposed method provides a substantial improvement in complexity with near-ML performance.