Research On Indoor Wireless Network Planning And Optimization Of 5G Based On Ray Tracing Method

The Fifth-Generation Mobile Communication Technology(5G)is the main development direction of a new generation of mobile communication technology.For the actual deployment planning of 5G wireless networks,the selection and availability of the spectrum is crucial.The 3GPP(38.101)protocol mainly specifies two frequency ranges in 5G,namely the FR1 and FR2.Compared with the Sub-3GHz frequency band,in the FR1,signal of the outdoor base station under the n77 to n79 frequency band has a larger link loss problem when covering indoor scenes,resulting in insufficient indoor deep coverage.The FR2 is suitable for indoor short-distance communication,but it is easily restricted by indoor environmental factors,thus affecting its coverage effect.In view of the above problems,based on the ray tracing method,simulation are conducted on 5G wireless network planning and optimization in O2I(outdoor to indoor)scenes and indoor scenes.According to the protocol content of 3GPP,n79 frequency band and 28 GHz frequency band in 5G system are selected in this thesis for the following research.The main contents are as follows:(1)In a typical residential environment,the scenes of outdoor-cover-indoor are simulated and analyzed based on the ray tracing method.Study path loss and delay spread from outdoor micro base station signal to different floors of multiple target building indoor in different micro base station position under the n79 frequency band.Analyze the influence of surrounding building distribution,floor height and vegetation factors on signal propagation and combine with the general process of base station position selection to get a better micro base station position.The simulation results provide guidance and suggestions for the position selection of 5G micro base station in the outdoor coverage indoor scenes of UMi(Urban Microcellular).(2)Based on the residential environment,through analyzing the indoor RSRP(Reference Signal Received Power),SINR(Signal and Interference plus Noise Ratio)and channel capacity of different target buildings,it can be concluded that LTE wireless network under B41 frequency band and 5G wireless network under n79 frequency band have their own advantages and disadvantages.Combined with the MIMO Multiple-antenna Technology and the macro-diversity mode of increasing small base station,under the condition that the space of receiver is limited,the indoor RSRP and SINR of different target buildings are studied and the channel capacity under the same transmission bandwidth is compared.The simulation results have certain guiding significance for the optimization of indoor coverage of 5G wireless network.(3)In indoor multi-storey stairway environment,comparing and analyzing the path loss and delay spread of the small base station signals of 28 GHz MMW(Millimeter-Wave)from different small base station position to indoor stairs on different floors,it is concluded that the path loss gap is obvious,but the delay spread gap is small.The receiver and transmitter select 4T4 R working mode,change the polarization characteristics of the antenna,and study the wireless network evaluation indexes and channel capacity of the transmitter and receiver in the co-polar modes or cross-polar modes at different small base station position,the results show that the RSRP and SINR of the co-polar modes transmission at the same small base station position are superior to that of the cross-polar modes transmission.By comparing and studying the RSPR and SINR of different small base station position,the results suggest that the indoor wireless network coverage of the 28 GHz MMW is more significantly affected by the indoor environment,and the position selection of the small base station greatly affects the indoor wireless network coverage;the channel capacity is compared with the conclusions of the existing literature to verify its simulation accuracy.Due to the limitations of the indoor environment,the transmitter and receiver will consider the objective conditions of limited space,combined with polarization diversity in MIMO diversity technology,research the RSRP and SINR when the transceiver is a dual-polarized antenna array or a single-polarized antenna array,then the corresponding setting suggestions are given.The simulation results have certain practical significance for optimizing the indoor coverage of the MMW band wireless network.(4)Based on the typical residential environment and indoor multi-storey stairway environment,the receiver is considered to move in the corridor between buildings 3 and 4 and along the stairs respectively,the statistical distribution of Doppler frequency shift at two different speeds is researched.The simulation results show that the statistical distribution of doppler frequency shift at the same base station position is consistent at different moving speeds,and the doppler frequency shift is determined by the moving speed of the receiver and signal wavelength.Discuss the statistical distribution and mathematical expectation of the 28 GHz doppler frequency shift at different base station position in the scene of moving along the stairs,compare the Doppler frequency shift of the transmitter and the receiver using the linear polarized omnidirectional antenna or the circular polarized omnidirectional antenna,then give the corresponding setting suggestions.Under the SISO system,single-polarized MIMO system or dual-polarized MIMO system,compare the received power of the receiver at different speeds with the static receiver,by calculating the RMSD(Root-Mean-Square Deviation),it is concluded that the greater the speed of the receiver has a greater impact on the received power.The MIMO system can suppress the impact of the speed on the received power compared to the SISO system,and the suppression effect of the dual-polarized MIMO system is superior to single-polarized MIMO systems.The simulation results provide a reference for wireless network optimization in mobile scenes.