| 摘要 |
<p>The synchronisation method consists in selecting, within a mobile station, at least one pseudo-random periodic sequence (PN) which corresponds and is synchronised with the reference sequence transmitted by a base station on a pilot channel, and received by the mobile station following a propagation path whatever the frequency offset between the transmitter and the receiver. Various possible sequences are tested, by calculating the quantities E[s(t).s<*)<t- tau )] and E[s(t).<*>s(t)], where E[.] designates the average value calculated over a predetermined integration time, tau designates a predetermined delay, and s(t) = r(t).c(t) designates the product of the signal received at baseband (r(t)) and the value (c(t)) of the tested sequence, and by calculating the ratio ¦E[s(t).s<*)<t- tau )]¦/ E[s(t).s<*)<t)]. The tested sequence is selected if the said ratio exceeds a predetermined threshold. <IMAGE></p> |
