Adaptive modeling of radio propagation channels

The author introduces an adaptive modeling scheme for characterizing radio propagation channels and shows its application to problems caused by adverse propagation conditions. The proposed scheme is based on a similar adaptive modeling scheme for an unknown system using an LMS (least-mean-square) adaptive filter. An identical and synchronized signal must be provided to drive the channel and the adaptive filter. For excellent performance, the adaptation of the adaptive filter must be faster than the variations of propagation characteristics. The adaptive modeling scheme can monitor channel characteristics while the data are being transmitted. The channel modeling scheme can automatically cope with adverse propagation effects without knowledge of propagation conditions.<>