It is well known that dynamic OFDMA systems potentially increase the spectral efficiency of wireless systems. They exploit diversity effects in time, space, and frequency by assigning system resources periodically to terminals. Informing the terminals about new assignments creates a signaling overhead. So far, simple signaling schemes have been presented in order to quantify the cost of signaling for such systems. However, by exploiting the correlation of sub-carrier attenuations in time, it is possible to decrease the cost of signaling significantly. In this paper we investigate such a scheme based on including the signaling cost in the optimization problem of sub-carrier assignments.