Switching space-time interference cancellation for OFDM systems with unsynchronized cells

Adaptive interference cancellation is addressed in an asynchronous orthogonal frequency-division multiplexing (OFDM) system with a frame containing a number of temporally distributed pilot symbols, e.g., as in the IEEE 802.16-2004 standard. A non-stationary symbol-by-symbol switching technique is proposed that is based on banks of the second-order statistics semi-blind solutions with on-line algorithm selection using a higher-order statistics criterion. Three banks of algorithms are formulated. Efficiency of the proposed algorithms is compared to the conventional stationary solution by means of simulations including a WIMAX (Worldwide Interoperability for Microwave Access) environment.