Power allocation for cognitive radio networks based on NOMA

The downlink power allocation of cognitive radio networks using non-orthogonal multiple access (NOMA)technologies was considered and studied in this paper,with the purpose of maximizing the number of secondary user in the access system and improving the system’s spectral efficiency.Without affecting the communication of primary user,a reasonable power allocation was performed for the secondary user,which lead to the maximum number of secondary user.When the system available power was not fully utilized,re-allocation the unused power among the secondary users accessing the system was considered to improve the system’s spectral efficiency.Simulation results showed that when the minimum rate of secondary users was set as 2.5 bit·s-1 and the number of secondary user requesting access to the system was set as 10,the spectral efficiency was improved by 13%