First, this paper analyzes the characteristics of multimedia training system, and points out the problem in current multimedia system design interiorly, according to the experience and the idea of industry design, put forward a method of multimedia training design based on user cognition.

Meanwhile,Pragmatic inference,dynamic contextual theory and lexical pragmatics from the perspective of cognitive pragmatics provide brand-new interpretation towards lexical items,which offer great enlightenments towards college English lexical teaching as well.

The ability that cognitive users detect the primary users is restricted by multi-path effect and shadow fading so that the detection probability of primary users cannot be enhanced.

In cognitive radio network,cognitive users(secondary users)must continuously monitor the spectrum to find the presence of the primary user.