Adaptive Frame Structure Design and Adaptation Control Mechanism in MIMO-OFDM Systems

With growing demand for large data rate and high reliability wireless communication services, such as multimedia services, link adaptation techniques have emerged as powerful tools for their significant transmission data rate increase, reliability enhancement and spectrum efficiency improvement. In this paper, firstly the redundancy of a unified frame structure has been analyzed and an adaptive frame structure is proposed in pilot aided spatial multiplexing MIMO systems, which provides three different pilot densities for high, middle and low vehicle speed scenarios respectively. Based on the proposed frame structure, a closed-looped control mechanism for frame structure adaptation is developed to adjust pilot density to track the time varying wireless channel characteristics. Finally, its effectiveness has been validated by Monte Carlo simulations.