Abstract: The propagation characteristics of the indoor radio wave with an important frequency of about2．4GHz in the radio intranet of IEEE802．11b were analyzed by the two-dimension FDTD （finite-different time-domain）method．The cumulative distribution probability and the power distribution of the received signal with the propagation distance were also given for the exciting source of2．4GHz continuous wave．The time-delays of the received signal for the line-of -sight and the non-line-of -sight scenarios with the impulse wave as the exciting source were then analyzed．The simulation results show that‚because of the serious dispersion‚the probability that the received signal power is higher than the average one when there is indoor furniture‚is proved to be lower than when there is no furniture．

Key words:  finite-different time-domain method, radio wave propagation characteristic, cumulative distribution prob-ability