EM-Based Maximum-Likelihood Sequence Detection for MIMO Optical Wireless Systems

—A major performance-limiting factor in terrestrial optical wireless (OW) systems is turbulence-induced fading. Exploiting the additional degrees of freedom in the spatial dimension, multiple laser transmitters combined with multiple receiver apertures provide an effective solution for fading mitigation. Although MIMO (Multiple-Input Multiple-Output) OW systems have been extensively studied in recent years, most of these works are mainly limited to symbol-by-symbol decoding. Maximum Likelihood Sequence Detection (MLSD) exploits the temporal correlation of turbulence-induced fading and promises further performance gains. In this paper, we investigate MLSD for IM/DD (intensity-modulation/direct-detection) MIMO OW systems over log-normal atmospheric turbulence channels. Even with a low-order modulation scheme such as On-Off keying which is typically used in OW systems, the complexity of MLSD might be prohibitive. We therefore present an iterative sequence detector based on the expectati...

• Type: Conference
• Year: 2009
• Where: ICC
• Authors: Nestor D. Chatzidiamantis, Murat Uysal, Theodoros A. Tsiftsis, George K. Karagiannidis
• Keywords: Communications, ICC 2009, MIMO OW Systems, OW Systems, Turbulence-induced Fading