Nonstationary multiple-antenna interference cancellation for unsynchronized OFDM systems with distributed training

Adaptive interference cancellation is addressed in an 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 nonstationary symbol-by-symbol switching technique based on banks of training-based and semi-blind estimators is analyzed by means of comparison with the conventional stationary pilot-based solution and with the nonasymptotic maximum likelihood benchmark especially developed for assessment of the proposed nonstationary interference cancellation algorithms.