Fast-group-decodable space-time block code

To make the implementation of high-rate space-time block code (STBC) realistic in practical systems, fast-decodable (FD) and group-decodable (GD) code structures have been separately introduced into STBC to reduce the sphere decoding complexity. However, no STBC has both the two code structures until now. In this paper, high-rate fast-group-decodable STBC (FGD-STBC, which has both FD and GD code structures) is proposed for the first time. We first derive the condition for FD code structure with the lowest sphere decoding complexity, then we prove that such FD code structure can be integrated with the GD-STBC for FGD-STBC construction. Analysis and simulation show that the proposed FGD-STBC has much lower decoding complexity and comparable performance with the existing FDSTBC.