Research On Optimization Of Multiuser Resource Allocation In Cognitive Radio Networks

With the development of wireless communication technology,the demand for wireless spectrum resources is ever growing,and the limited wireless spectrum resources become more and more scarce.Dynamic spectrum allocation in cognitive radio greatly eases the contradiction between spectrum scarcity and insufficient spectrum utilization.On the one hand,in the face of complex wireless environment,how to allocate resources rationally under different sensing conditions,improve spectrum utilization,and ensure fairness among users are the current research focus.On the other hand,with the advent of problems such as energy consumption and environmental degradation,how to reduce energy consumption in resource allocation and achieve green communications have also become urgent problems to be solved.In view of the above problems,different system models for different optimization objectives are built in this thesis,and the multi-user cognitive radio resource allocation algorithms based on orthogonal frequency division multiple access(OFDMA)are studied.The main work and contributions are as follows:1.An OFDMA multi-user resource allocation system model based on spectrum efficiency under ideal sensing is established.For the diversity of subcarriers to multi-users and real-time system problems,aiming at maximizing system user throughput,a low-complexity two-step algorithm is proposed,which includes an improved worst subcarrier prioritization algorithm and a linear water flood power allocation algorithm that incorporates interference judgments.The simulation results show that the proposed algorithm can effectively reduce the computational complexity and achieve high real-time performance while achieving high throughput.2.An OFDMA multi-user resource allocation system model based on system interference control under non-ideal sensing is established.For the problem of ensuring the communication quality of the primary user,aiming at minimizing the interference to the primary user,a two-step algorithm is proposed.In the first step,the subcarrier channel gain optimal allocation strategy is adopted.In the second step,the power allocation strategy combined with the hybrid integer non-linear programming model and the sub-gradient algorithm is used.The simulation results show that the proposed algorithm effectively reduces the interference suffered by the primary user in the presence of perceptual error,ensures the transmission rate of secondary users and improves the spectral efficiency.3.An OFDMA multi-user resource allocation system model based on energy efficiency under ideal and non-ideal sensing is established.For the problem of energy conservation,environmental protection and economic benefits,a new energy efficiency standard is defined from the perspective of economics to describe the economic benefits of unit energy consumption.Aiming at the optimization of users' economic benefits in resource sharing,a two-level Stackelberg game model is established and a distributed interference pricing algorithm based on system economic efficiency is proposed.The simulation results show that the proposed algorithm achieves the balance between secondary users' performance and the primary user's benefit under different perception results,maximizes the economic efficiency of the system,and has certain economic practicability.