Cognitive Radio Research And Implementation On Engine Used For Wide-band Self-adaptive Communication

The most prominent feature of the cognitive radio network is its intellect. And the key to realize its intellect is to build a reconfigurable cognitive engine in the wireless network. Utilizing the intellect of cognitive engine, adaptive communication realizes its adaptive function. Compared with the conventional communication system, in an adaptive communication system, the communication system, communication data rate, and the communication frequency is not fixed, it can avoid interference to the maximum, reduce the communication error rate. At the same time, it can avoid interception or increase intercepted difficulty. Combined with project requirements, a study based on the application of satellite communication link, the transmitter using cognitive technology, according to circumstances of the channel occupancy and subject to interference, it can select the band, data rate and modulation mode adaptively to avoid interferences.In this thesis, the main work is to study on the cognitive engine and achieve its awareness and decision-making functions. The output parameters of the cognitive engine made its decision-making function achieve. Firstly, get the perceived parameters by spectrum sensing from the wireless environment. Secondly, put this sensing information into the decision module, while set other input parameters for the cognitive engine. At last the cognitive engine makes a decision to achieve parameter opti mization of the transmitter. In this thesis, a variety of sensing algorithms have been studied and realized simulation, through the normalization process, the cognitive engine optimization is changed from multi-objective function to a single objective function and the improved binary particle swarm algorithm is used to achieve its optimization decisions. Finally, simulation analyses are made respectively for the three communication modes: the minimum power consumption, minimal error rate, maximized the data rate, and the performances of the optimization algorithm are confirmed.