Research On Adaptive Spectrum Sharing And Spectrum Scheduling Algorithms In Interference Alignment

Cognitive radio (CR) is an intelligent radio communication technology that can automaticlly sense the variation of communication environment, through the interacting information with communication conditions, and adaptively adjust the transmission parameters of cognitive devices to adapt to the changing communication environment. CR can effectively solve the contradiction between the scarce spectrum resources and the low efficiency of spectrum utilization through secondary users (SUs) dynamic shared spectrum with the primary user (PU). But secondary users have inevitably engendered interference to primary user, so interference alignment (IA) is applied to eliminate the interference in spectrum sharing. IA can separate the interference signal and the desired signal by overlapping interference to eliminate interference at the receivers. However, the problem what the decline of the desired signal signal to interference plus noise ratio (SINR) under some channel states. This may influence the quality of the Quality of Service (QoS) of PU. Hence, the problems of spectrum sharing in CR system and IA technology have been launched in-depth research in this thesis, The work accomplished mainly is as follows:(1)Establish the spectrum sharing pattern based on I A. In the spectrum sharing pattern of CR network, the analysis simulation and verification about the distributed IA algorithm performance are cattied out.PU and SUs dynamic share the authorization spectrum. In order to ensure the QoS and priority of PU, PU and SUs communicate by forming IA network. In the process of dynamic spectrum sharing, the multi-user interference which is caused by SUs access is eliminated by distributed IA algorithm.(2)For the problem of the priority of guaranteeing the PU’s reliable communication in CR network and serious signal to interference plus noise ratio (SINR) decrease of IA under some channel states, an adaptive spectrum sharing scheme based on IA is proposed; two-algorithm of spectrum sharing is proposed according to the number of PU in the spectrum sharing pattern based on IA:①under the condition of single PU, it proposes an adaptive specific spectrum sharing algorithm based on MinIL algorithm,②in the case of multiple PU, it gives an adaptive specific spectrum sharing algorithm based on Max-SINR algorithm. The analysis simulation of two-algorithm performance is came true in the paper. (3)For the problem of serious signal to interference plus noise ratio (SINR) serious decline under some channel states after the application of IA in CR network, an approach of Power Allocation algorithm with IA Based Frequency Scheduling in CR network is given. The approach measure the overall performance of network with adopting the overall spectrum efficiency or energy efficiency in CR network. The approach can optimize the overall spectrum efficiency or improve the overall energy efficiency in CR network by power allocation in the users, furthermore, the Power Allocation algorithms in IA with Equal Optimization and the Power Allocation algorithms in IA with Middle-Course Optimization Based Frequency Scheduling in CR network are proposed. The analysis and simulations of two algorithms performance are cattied out in the thesis. The computational complexity of two proposed algorithm are seriously analyzed.