Study On Resources Allocation In Cognitive Radio Networks Based On Sensing Information

The cognitive radio technology improves the efficiency of spectrum utilization by theoptimal resources allocation. With the rapid development of wireless communicationservices, the increasing number of users, the expansion of communication range andinterference between authorized user and cognitive user promote the development ofcognitive radio networks to the direction of cooperative. The time-varying of availablespectrum and the scalability of transmission power make resource management andallocation of cognitive radio networks become prominent problems. At the same time, theresources allocation algorithms also need to meet the quality of service (QoS) and fairnessdemand of users. In addition, resources allocation in cognitive radio networks is based onspectrum sensing.First, we study the resources allocation in cognitive radio networks with requirementsof users. Based on sensing information from cognitive users to authorized user，considering the confidence level of subband and the throughput requirement of cognitiveuser, the algorithm of spectrum scheduling scheme is proposed. The scheme directlyallocates subbands to cognitive users. A subbands-grouping algorithm is presented and thetransmission speed, fairness and reliability of the network are analyzed.Then, considering the limit of the throughput for original resources allocationalgorithm, the algorithm is to construct a optimization problem joint power and subbandsallocation, in which the cognitive users can transmit with a proper power as the authorizeduser is active. Simulation results show that the proposed algorithms improve thethroughput of the cognitive radio networks.To further enhance the utilization of network resources, considering the cooperativeof users, we mainly concern the relay selection and power allocation in cooperativecognitive radio network. An optimal relay selection and power allocation algorithm basedon sensing information has been presented. The interference from authorized user tocognitive users has been considered as well as the average interference constraint of theauthorized user. To maximize the throughput of the cognitive radio network，one best relay will be selected，besides optimal power allocation is performed between the sourceand relay. Then the performance promotion from the sensing information to the networkperformance is analyzed and proved by simulation. Finally, a circumstance that there isonly cognitive users’transmission has been discussed.