Fluid Antenna Enabled Space-Time Block Coding With Achievable Rate Optimization

The conventional space-time block coding (STBC) technique offers advantages such as low detection complexity and full-diversity transmission while suffering from a reduced achievable rate. Inspired by the novel concepts of fluid antennas (FAs) exploiting extra spatial flexibility, we propose to maximize the STBC achievable rate by jointly optimizing the positions of transmit and receive FAs. In order to solve the corresponding highly non-convex problem, an alternating optimization (AO) algorithm based on successive convex approximation (SCA) is employed to obtain a locally optimal solution. Simulation results reveal the superiority of the FA-enabled STBC (FA-STBC) system over its fixed-position antenna (FPA) and STBC counterparts within limited FA regions.