| In the future fifth-generation(5G)wireless communication systems,the number of mobile terminals and the users’ data traffic demand will continue to grow explosively.As a new network architecture,small cell networks can be deployed in the hotspot area to provide a higher transmission rate,which is widely studied and analyzed.However,the diversity of urban terrain,the irregularity of the surrounding buildings and shelters cause the coverage area and coverage range of high-density small cell is irregular,which will bring a new challenge in small cell network coverage and capacity performance analysis in that complex transmission environment.To analyze the influence of the complex transmission environment on cellular coverage boundary,the fractal characteristic of actual cellular coverage boundary is verified and the Hurst exponent which shows the degree of the self-similarity of the cellular coverage boundary is estimated based on the measured data and fractal theory in this thesis.The results show that the coverage boundary of actual cellular is irregular and explosive in angle domain,and it shows self-similarity and long-range dependence in statistical characteristics.By using fractal theory and stochastic geometry,this thesis proposes a seaming fractal small cell network topology model and anisotropy path loss model,and the coverage probability,multi-user capacity and area spectral efficiency in multi-cells multi-antennas scenarios have been derived.Moreover,we also analyze and simulate the influence of wireless fractal small cell coverage boundary and the anisotropy path loss model in complex transmission environment on the performances of small cell networks.Based on fractal theory,this thesis proposes a wireless fractal small cell network topology model,which opens up a new research idea for cellular network and cellular coverage boundary modeling.The analysis results of this thesis have some guiding significance for the network modeling and small cell deployment. |
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