Design of Pilot Pattern for Channel Estimation in OFDM Systems

Channel estimation is necessary for coherent detection in orthogonal frequency division multiplexing (OFDM) receivers. For accurate estimation, known pilot symbols are sent with data symbols at the transmitter. In general, these pilot symbols are placed with a regular pattern in two-dimensional (2-D) time-frequency grid. In a static additive Gaussian noisy channel, the channel estimation performance is known to depend not on the pilot pattern, but only on the pilot density. In time-variant frequencyselective fading channel, however, both the pilot pattern and the pilot density significantly affect the channel estimation performance. In this paper, we analytically design the pilot pattern so as to maximize the channel estimation performance when a piecewise linear interpolation filter is used for channel estimation in data-inserted region. Finally, the analytic design is verified by computer simulations.