Study Of Spectrum Sharing Technology Of Multi-user Scenario In Wireless Communication Systems

With the ever-increasing of the users and traffic demands,the spectrum resource faces new challenges.Study of spectrum sharing technology in the wireless communication system has important meaning.To begin with,conceptions of stochastic network calculus are introduced,along with some important theorems and deductions,including stochastic arrival curve,stochastic service curve,delay bound,backlog bound and leftover service theorem.The expressions of maximum horizontal distance and maximum vertical distance are introduced applying min-plus algebra.And then,a multi-user spectrum sharing model based on cognitive radio is proposed to study system performance of the spectrum sharing mechanism.The stochastic arrival curve and service curve are derived for further analysis.Guaranteed service of secondary users is studied.Based on these,the delay bound,probability delay constrain and minimum transmission rate are studied.Further,the analysis is expanded to the transmission power and energy consumption of the system.Finally,the system-level simulation is used to study the spectrum sharing technology on the licensed spectrum.LAA(Licensed-Assisted Access)and Wi-Fi coexistence scenario is modeled and studied.The features of LTE(Long Term Evolution)and LAA are introduced firstly.The structure and some models are introduced.Three categories of Listen-Before-Talk mechanisms are studied,which are deployed by LAA to achieve fair coexistence.Carrier sensing and accessing mechanism in Wi-Fi is studied and the process in the platform is given.The simulation results show that LAA with LBT mechanisms can be "friendly neighbor"to the Wi-Fi system on the unlicensed band.