A Modified QRD-M Algorithm Based on Layer Branch Pruning for MIMO Systems

In this paper, a low complexity Modified QRD-M (MQRD-M) algorithm based on limited tree search is proposed for MIMO systems. The sphere radius and candidate set of each branch are considered to reduce the computational complexity. The sphere radius is efficiently acquired through the QRD detection based on pruning off unnecessary survival branches at each layer. Moreover, the candidate set of each branch is used to cut down the metric computation for it is much smaller than modulation set. Simulation results show that the proposed MQRD-M algorithm can achieve near-MLD performance and its average metric computation is lower than conventional QRD-M algorithms.