the character of LS algorithm’s result in time-domain was paid much attention to.At the same time
the character of Channel Impulse Response(CIR)in time-domain was taken into account.It was proposed to detect energy of CIR’s tap of LS algorithm’s result in time-domain and search the effective order of radio channel conversely.By theoretical analyses and computer simulation
it is indicated that this method shows good performance in estimating effective order of radio channel.