| 摘要 |
A cognitive radio system comprising a master node and a plurality of mobile terminals operable to communicate with each other within a licensed operating band of a primary user device. The master node receiving from at least one of the mobile terminals (5) primary user transmission information indicative of a signal strength of a primary user transmission received at the at least one mobile node (5); obtaining position information for each of the at least one mobile terminal (5); estimating an area (17) of possible transmission overlap between the master node (3) and the primary user (4) using the received primary user transmission information and the obtained position information; comparing the location of each mobile terminal (5) with the estimated area (17) of possible transmission overlap; and controlling the operation of the mobile terminals (5) in dependence upon a result of the comparison in order to avoid interference to the primary user (4) by the master node (3) and the mobile terminals (5). Some or all of the mobile terminals (5) act as sensor nodes to sense and measure the signal strength of primary user (4) transmissions. The determined signal strength may be reported within a Medium Access Control (MAC) layer frame or as part of a Random Access Procedure. |
