连续衰落信道下适用于酉空时调制的最大似然多符号差分检测算法

Maximum-Likelihood Multiple Symbol Differential Detection for Unitary Space-Time Modulation in Continuous Fading

为酉空时调制系统设计的多符号差分球形译码(MSDSD)能以较低复杂度获得最大似然(ML)检测性能。但是,该算法基于准静态信道假设,当将它用于快衰落信道时会出现严重的误码平层现象。本文基于连续衰落信道假设,推导了一种ML度量的递推形式,并将其嵌入自动球形译码算法中,得到了的多符号差分自动球形译码(MSDASD)算法。该算法适用于一般酉空时星座,克服了MSDSD的误码平层现象,可达到ML检测的性能,其平均复杂度在大多数情况下低于相同假设下的判决反馈检测算法。

Recently, a Multiple Symbol Differential Sphere Decoding （MSDSD） algorithm for unitary space-time modulation over quasi-static channel is proved to achieve the performance of Maximum-Likelihood （ML） detection with relatively low complexity. However, an error floor occurs if the algorithm is applied to rapid-fading channels. Based on the assumption of continuous fading, a Multiple Symbol Differential Automatic Sphere Decoding （MSDASD） is developed by incorporating a recursive form of an ML metric in the automatic sphere decoding algorithm. The proposed algorithm is suitable for arbitrary unitary constellations and eliminates the error floor caused by MSDSD over fast fading channels. Compared with decision-feedback detection under the same assumption, MSDASD achieves performance of ML detection with much lower complexity at moderate to high signal-to-noise ratios.