Research On Multiuser Resource Allocation Optimization In Spectrum Space Resource

As one of the most rare and precious natural resources in the world,the wireless spectrum is managed by the radio management departments of different countries.With the increasement in service quality requirements and various wireless services,this way of management leads to a lack of spectrum resources and a low utilization rate of most frequency bands.In this case,how to improve the utilization of spectrum resources becomes an urgent issue.Under the existing infrastructure and technical conditi ons,the emergence of Cognitive Radio(CR)has brought a new direction of improving the utilization of spectrum resources.Relevant researches show that the combination of cognitive radio and dynamic spectrum access(DS A)tec:hnology can greatly improve the efficiency of spectrum.The essence of cognitive radio to improve resource utilization is how to better utilize the spectrum resources which temporarily didn't occupied by authorized users.In the existing theoretical and literature achievements,first,the system is generally mathematically modeled,and then the target optimization function is solved by a series of strategies or algorithms,thereby improving the system resource utilization.Newer research results show that the allocation of spectrum from the joint dimension(joint time domain and frequency domain,joint space and frequency domain,joint users and channels,etc.)can more effectively utilize the multidimensionality of spectrum resources and improve system efficiency.Based on work of predecessors,this paper analyzes the spectrum resources from the joint multi-dimensional perspective,and proposes an improved Bandwicdth-Power Product(BPP)metric to measure the system resource allocation efficiency,considering the spectrum resources in the space dimension reuse.The works of this paper are described as follows:(1)Introduce the background and significance of cognitive radio.Interpret the meaning of spectrum resource allocation optimization and the research status of joint spectrum resource optimization.(2)Interpret the trend development,echnical characteristics,access model and challenges on DSA in detail.(3)The resource metrics of BPP are improved.The gain of the spectrum resource in the spatial domain is measured.The system resource allocation model is established.The decomposition theory is used to optimize the target.The optimal allocation of single users is solved by the convex optimization theory.In the case of multi-users,the final allocation scheme is obtained by the gradient descent method.The simulation results show that the proposed metrics and algorithms improve the spectrum efficiency under the premise of ensuring the communication quality of authorized users.(4)In the MIMO(Multiple-Input and Multiple-Output)and CR combination scenario,the efficiency of spatial multiplexing is improved.The system optimization solutison model is established,and the stage selection strategy of beam selection and user selection is proposed.Firstly,the optimal beam matrix is selected,and then the specific cognitive users to be transmitted are determined.The simulation results show that our proposed allocation strategy maximizes system throughput while minimizing interference to authorized users.