Performance bounds for channel tracking algorithms For MIMO systems

In this paper we derive performance bounds for tracking time-varying OFDM multiple-input multiple-output (MIMO) communication channel in the presence of additive white Gaussian noise (AWGN). We discuss two channel tracking schemes. The first tracks the filter coefficients directly in time-domain, while the second separately tracks each tone in the frequency-domain. The Kalman filter, with known channel statistics, is utilized for evaluating the performance bounds. It is shown that the time-domain tracking scheme, which exploits the sparseness of the channel impulse response, outperforms the computationally more efficient, frequency-domain tracking scheme, which does not exploit the smooth frequency response of the channel.