关键词: 多输入多输出, 信号检测, 运算复杂度, 球形译码算法, 最小均方误差算法

Abstract: Among all of the signal detection algorithms in multiple-input multiple-output systems, the capability of sphere decoding algorithm is most close to the capability of maximum-likelihood algorithm. But the calculation complexity of the sphere decoding algorithm is still very high. To decrease the calculation complexity of sphere algorithm, a new sphere decoding algorithm was proposed. The new algorithm was combined by an improved fast sphere decoding algorithm and the Minimum Mean Square Error (MMSE) algorithm. The improved fast sphere decoding algorithm can increase the decreasing rate of sphere radius via multiplying the contraction process of sphere radius by a constant parameter, so that it can reduce the number of signal points in search process to decrease calculation complexity. Meanwhile, the MMSE algorithm can reduce the interference that caused by noise, so that it can decrease the calculation complexity caused by the process of searching noise points. The channel matrix of the MMSE algorithm was applied to the improved fast sphere decoding algorithm, so these two algorithms can be combined with each other efficiently, and the combined algorithm can further reduce the calculation complexity. The simulation results show that, when Signal-to-Noise Ratio (SNR) is less than 10dB, the proposed algorithm improves average performance by 9% compared with original sphere decoding algorithm. Multiple-Input Multiple-Output (MIMO); signal detection; calculation complexity; Sphere Decoding (SD) algorithm; Minimum Mean Square Error (MMSE) algorithm

Key words: Multiple-Input Multiple-Output (MIMO), signal detection, calculation complexity, Sphere Decoding (SD) algorithm, Minimum Mean Square Error (MMSE) algorithm