The location, number, and power of pilot symbols embedded in multicarrier block transmissions over rapidly fading channels, are important design parameters affecting not only channel estimation performance, but also channel capacity. Considering orthogonal frequency-division multiplexing (OFDM) systems with decoupled information-bearing symbols from pilot symbols transmitted over wireless frequency-selective Rayleigh-fading channels, we show that equispaced and equipowered pilot symbols are optimal in terms of minimizing the mean-square channel estimation error. We also design the number of pilots, and the power distributed between information bearing and pilot symbols, using as criterion a lower bound on the average capacity. Numerical results corroborate our theoretical findings.
|Original language||English (US)|
|Number of pages||8|
|Journal||IEEE Transactions on Information Theory|
|State||Published - Sep 2004|
Bibliographical noteFunding Information:
Manuscript received April 30, 2001; revised March 2, 2004. This work was supported by the National Science Foundation under Grant CCR-10105612. The material in this correspondence was presented in part at the International Symposium on Signals, Systems and Electronics (ISSSF’01), Tokyo, Japan, July 2001.