Low-Complexity Maximum Likelihood Detection of Orthogonal Space-Time Block Codes

Space-Time Block Codes (STBCs) from Orthogonal designs (OSTBCs) are attractive since they achieve the maximum diversity, the maximum coding gain, and the highest throughput. These codes are used in Multiple-Input Multiple-Output (MIMO) systems to introduce high capacity gains. Their design allows for simple Maximum Likelihood (ML) decoding. The decoding complexity is very critical for practical employment of MIMO systems. Therefore, in OSTBCs proposed by Alamouti and Tarokh et al., each transmitted symbol is decoded separately, resulting in linear decoding complexity.