Shenyang Institute of Automation, the Chinese Academy of Sciences
The present invention relates to wireless cognitive sensor network technology. Disclosed is a medium access control method, based on broadcast preamble interception, for a cognitive sensor network. A cognitive node in a cognitive sensor network uses a periodic sleep-wake-up mechanism. First, spectrum-sensing technology is used to determine a state of a primary user, and if the primary user is not active, a data-sending node establishes a communication link by means of broadcasting a preamble. According to a wake-up sequence, each neighbour node takes information about the number of hops for reaching a gateway into consideration at the same time, and autonomously decides to act as a relay node for data forwarding. In addition, since a transmission collision between the cognitive node and the primary user is possibly caused by the primary user returning or a missed alarm, the present invention uses a re-transmission mechanism based on confirmation so as to ensure the reliability of data packet transmission. The present invention is independent of a common control channel, and can realise the low-overhead and reliable access of a licensed frequency band by a cognitive sensor network.