Abstract: Based on the principle of the M-ary orthogonal spread spectrum, we propose a fast variable-rate-supported synchronization method by an assistant logic channel. Data and synchronization information are transmitted in data and assistant channel respectively. Different combinations of Barker codes make up the synchronization codes to represent different rates. By the principle of the matched filter and the characteristic of mobile channels, an adaptive threshold algorithm is also proposed for Ad-hoc networks.

Key words: spread spectrum, Ad-hoc networks, matched filter, adaptive threshold