In this paper, a direct self-structured adaptive fuzzy control is introduced for the class of nonlinear systems with unknown dynamic models. Control is accomplished by an adaptive fuzzy system with a fixed number of rules and adaptive membership functions. The reference signal and state errors are used to tune the membership functions and update them instantaneously. The Lyapunov synthesis method is also used to guarantee the stability of the closed loop system. The proposed control scheme is applied to an inverted pendulum and a magnetic levitation system, and its effectiveness is shown via simulation.

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MIMO-OFDM is the promising technique in the future of wireless communications as it combines the properties of Multiple Input Multiple Output (MIMO) systems with the properties of Orthogonal Frequency Division Multiplexing (OFDM). However, its sensitivity to frequency offsets, usually resulting in inter-carrier interference (ICI), makes frequency synchronization necessary for data recovery in the receiver side. In this paper, a preamble-based frequency offset compensation method is proposed in which every single subcarrier is separately compensated for all the frequency offsets that are experienced while passing through the fading channel. Simulation results show that our proposed scheme is accurate in multipath fading channels and precisely recovers the data symbols.