Research On Coexistence Technology Of 5G And Wi-Fi In Unlicensed Frequency Bands

With the rapid growth of wireless data services,the data pressure on the existing frequency bands is also increasing,and higher frequency bands and unlicensed frequency bands will become the main targets for service traffic offloading.Unlicensed frequency bands have natural advantages over other frequency bands in terms of technical supervision.In the formulation of 5G standards,3GPP also included unlicensed frequency bands.Given the open sharing principle of this band,systems deployed on unlicensed frequency bands must consider fair coexistence issues with other systems.This thesis focuses on the coexistence access technology of 5G and Wi-Fi on unlicensed bands.Most of the existing coexistence schemes separate 5G from Wi-Fi in the time dimension.In this thesis,we start from the frequency dimension and divide the channel into several mutually orthogonal sub-channels.By designing a multi-channel access mechanism,the fair coexistence of 5G and Wi-Fi system are realized.The thesis first studies the multi-channel access mechanism and proposes a control channel-assisted multi-channel access scheme.By dividing the channel into a plurality of mutually orthogonal subchannels,different nodes can communicate with each other without interference on each subchannel;further,the control channel assists scheduling and allocating channel resources,thereby effectively improving throughput performance.The Markov model is established to analyze the saturation throughput of the system from a theoretical perspective,and the corresponding simulation verification is carried out.The simulation results show that compared with the single-channel access scheme widely used at present,the throughput and delay performance with the multi-channel are greatly improved.Secondly,based on the proposed multi-channel access mechanism assisted by the control channel,this thesis proposes a specific implementation scheme for the coexistence of 5G and Wi-Fi on unlicensed frequency bands.By designing the interaction process between the 5G gNB and the Wi-Fi AP,interference and collision on the subchannel can be avoided,and the network throughput is significantly improved under the premise of ensuring fair coexistence of the 5G and Wi-Fi systems in the frequency band.Simulation results verify the effectiveness of the proposed scheme.