Modeling And Performance Analysis Of Traditional Microwave And Millimeter Wave Hybrid Heterogeneous Cellular Networks

Millimeter wave communication has solved the problem of the spectrum scarcity of low-frequency signal with its large bandwidth and rich spectrum resources,and become one of the key technologies of 5G communication.However,because of its susceptibility to blockage,coverage blind spots may occur when used alone.The traditional microwave(sub-6GHz)and millimeter wave can are used together to form a hybrid heterogeneous cellular network,which can simultaneously provide comprehensive coverage and high rate communication.On the other hand,it is currently in a critical period of transition from 4G to 5G.There are both 4G base stations and 5G base stations in the communication networks,and communication equipment can receive two signals at the same time.Therefore,sub-6GHz and millimeter wave hybrid heterogeneous cellular network has important research significance.First of all,this paper constructs a non-uniformly distributed sub-6GHz and millimeter wave hybrid heterogeneous cellular network model in view of the correlation between the distribution of different base stations.In this model,the sub-6GHz base stations are distributed according to the Poisson point process,and the millimeter wave base stations adopt the modified Poisson hole process with random direction sector,which is more flexible than the original shape and is closer to the actual scene.Based on this model,this paper uses the mathematical tools of random geometry,and uses the method of integrating the nearest sector emptying area to calculate the interference.The approximate mathematical expressions of the SINR coverage and rate coverage of the non-uniform network are obtainsed,and verified by Monte Carlo simulation.The influence of various parameters on network performance is discussed.The results show that the SINR coverage probability increases with the increase of the average cell radius,and the SINR coverage probability decreases with the increase of the sector radius and the central angle.Due to the different signal characteristics,sub-6GHz base station has a large impact on the SINR coverage,while the millimeter wave base station is smaller under the same degree of station density changes.Changing the density of the millimeter wave base station will reduce the average bandwidth obtained by users,affect the achievable rate of users,and cause a decrease in rate coverage.Secondly,considering the possible estimation error of antenna direction of arrival,this paper proposes a sub-6GHz and millimeter wave hybrid heterogeneous cellular network model with beam alignment error.It is assumed that the distribution of sub-6GHz base stations,millimeter wave base stations and users in the cellular network follow the different independent Poisson point process,and the sub-6GHz base stations are equipped with omnidirectional antennas,and the millimeter wave base stations and users are equipped with directional antenna arrays.In this paper,an easy-to-handle antenna array model is used to model the main performance parameters of the antenna,which are modeled as a function of the number of array elements,and the enhanced directional beam model and beam alignment error model are established.Then,the hybrid heterogeneous cellular network with beam alignment error is analyzed,and the theoretical expressions of SINR coverage rate and network energy efficiency are derived.The simulation data are compared to verify the theoretical expressions,and how the antenna size and alignment probability jointly affect the network performance is analyzed.The simulation results show that when the antenna has beam alignment error,the performance of the network under the same conditions will be greatly reduced.When the beam error is small,the beam alignment probability has a major impact on the performance.When the beam error is large,the antenna gain plays a leading role in the performance.Both of them will affect the performance of the system and cause the non-monotonic change of the network performance.The increase of millimeter-wave base station density within a certain range will improve the energy efficiency of the network.