Multicarrier systems with imperfect channel knowledge

Most multicarrier system designs assume perfect knowledge of the transmission channel. However in practice, the accuracy in channel identification is limited either by errors in channel estimation or by variations in the channel once it had been estimated. When not accounted for, these channel mismatch errors degrade the performance of our system and can lead to unacceptably high bit error rates. In this paper, we extend the existing multicarrier design concepts to systems with imperfect channel knowledge. We assume a Rayleigh fading channel, and study the impact of errors due to variations in the transmission channel. We develop a model for these errors, analyze their distribution, and derive analytic expressions for the probability of error of our system in the presence of these errors. We then extend the existing loading algorithms, taking into account the channel mismatch errors, and show the improvement in performance over the conventional multicarrier system designs