Low-cost Design Of Massive Access For Cellular Internet Of Things

With the widespread application of the Internet of Things(Io T)in various fields of economy and society,the number of Io T devices has experienced explosive growth.Therefore,the B5 G cellular Io T needs to adopt massive multiple-input multiple-output(MIMO)technology to achieve the massive access in a wide area.However,the traditional massive MIMO technology has the problems of high cost and high power consumption.This thesis proposes three low-cost massive access design schemes based on low-cost hardware and low-cost technologies.Firstly,this thesis proposes a massive access scheme with low hardware cost.Combining low-resolution ADCs,a limited number of RF links and other low-cost hardware,a massive access framework including channel estimation,uplink(UL)data transmission and downlink(DL)data transmission is designed for B5 G cellular Io T.This thesis derives closed-form expressions for uplink and downlink spectral efficiency through analysis and deduction,thereby revealing the impact of low-resolution ADCs on spectral efficiency.According to the results,a time allocation algorithm with low complexity is given to reduce system energy consumption.The simulation results verify the effectiveness of the proposed algorithm.Secondly,this thesis proposes a low-power design of massive access.Based on the low power consumption characteristics,an Intelligent Reflecting Surface(IRS)-assisted coverage enhancement framework is designed for cellular Io T.The corresponding channel estimation,uplink data transmission and downlink data transmission schemes are given.Moreover,this thesis derives closed-form expressions for the uplink and downlink spectral efficiency,thus revealing the impact of the important parameters of IRS on the spectral efficiency.With the goal of minimizing system energy consumption,this thesis proposes a low-complexity time allocation algorithm.The simulation results show that the proposed scheme has lower power consumption.Next,this thesis proposes a low-cost design of massive access in the Terahertz(THz)frequency band.Based on the device-intensive sub-connection architecture,this thesis designs a massive access framework with the aid of an IRS.This thesis gives a detailed uplink and downlink data transmission scheme and derives closed-form expressions for uplink and downlink spectral efficiency,thus revealing the impact of important parameters on spectral efficiency.The simulation results confirmed the accuracy of the theoretical analysis.The research results of this thesis can provide theoretical basis and technical support for the design of B5 G cellular Internet of Things.