Cognitive Interference Coordination Technology For Dense Heterogeneous Cellular Network Based On Stochastic Geometry

Dense heterogeneous cellular network is capable of boosting the system capacity in a cost-effective manner.It will be a key architecture for future cellular communications.Cross-and co-tier interferences are two barriers to take advantage of the potential of dense networks.Cognitive Radio(CR)can effectively mitigate interference in dense cellular networks.This paper studies the effect of the information sensed at small cell base stations on system performance and proposes two spectrum-sharing schemes between macrocell and small cell,as well as among small cells.In this paper,the orthogonal spectrum sharing scheme between macrocell and small cell is combined with the random access spectrum sharing scheme and the sensing access spectrum sharing scheme among small cells,respectively.Bounds on the intensity of active small cells that satisfy a given outage constraint in these schemes are theoretically derived via a stochastic geometry model.This paper conduct simulations to evaluate the performance of the proposed schemes.The above analysis is performed in a single-channel scenario,whereas in actual small cell networks,the number of available channels is far more than one,and there is a large difference in the number of users accessing each small cell.This paper focuses on the design of two interference coordination schemes in multichannel cognitive dense cellular networks with the uncertain user numbers,and analyzes their system performance by applying the tools of stochastic geometry.In addition,unlike the assumption that small cell users are always located at the border of small cells,a more general user distribution model is used here,and the result is robust to user location changes.By applying the tools of stochastic geometry,the spectrum efficiency is derived as a function of the radius of exclusive zone in the sensing access spectrum sharing scheme.Based on the theoretical result,the optimal radius is obtained by a one-dimension numerical search method.The optimal exclusive radius can make a good tradeoff between the spectrum reuse opportunity and interference mitigation in dense cellular networks.Simulation results show that the proposed scheme together with optimal exclusive radius can achieve a better spectrum efficiency than those in the existing literatures.