Research On Cognitive User’s Time Allocation Method Based Onthe Mobility Of The Primary User

The main purpose of cognitive radio is that cognitive users can use the licensed spectrum when primary users don’t occupy the spectrum or primary users’ communication qualities not influenced by the cognitive user’s transmission, so as to improve the efficiency of spectrum utilization. Cognitive radio techniques mainly include spectrum sensing, power control and spectrum management techniques. Traditional cognitive radio techniques mainly aim at the primary user and cognitive user in static scence. With the development of the IEEE 802.22 standard, the research on the mobility of the user has become a hot research topic, because of the cognitive network’s widely used in multimedia access technology, and the protocol of multimedia access technology based on the allocation of time. Therefore, this dissertation focuses on the mobile scenarios of primary usersand time allocation method of cognitive users.In this dissertation, we firstly construct the time distribution model of the primary user in and out of the interference region of the cognitive radio network. Secondly, from the view of the user’s movement, the available transmission time for a single user and the problem of sensing time threshold is put forward. Because of the mobility of the primary users, the spectrum sensing algorithm sensing the primary users can not be more accurate using the longer of the sensing time. In order to give the time parameter design method of the application, especially for the random walk modelwhich is most commonly used, the dissertationgives a single user’s optimal transmission time and sensing time threshold. Thirdly, in order to explore the capacity of the cognitive radio system of cognitive users’ capacity in mobile scenarios when the probability of interferenceis lower than the maximum interference probability the primary users’ communication allowed. A conclusionis drawn that the total transmissiontime of all the cognitive users is constant. Finally, this dissertation studies the transmission outage probability and the interference probability of the cognitive user to ensure the communication of the primary user.