Research On The Performance Of D2D Communication System In The Fading Channel Under Interference Environment

With the development of wireless communication technology,the rapid increase in mobile devices has made spectrum resources tight.Compared with traditional cellular network communication technology,D2D communication technology can not only improve the the utilization of spectrum resources,save bandwidth and power consumption,but also reduce transimission delay and improve system throughput.While ensuring the communication quality,the communication pressure of the base station is greatly reduced,which has aroused widespread concern in the academic community.In this paper,we use stochastic geometry knowledge to construct ad-hoc D2D and cellular D2D communication models,and study the performance of the two models separately.The main work is as follows:(1)In the ad-hoc D2D communication system model,this paper discusses the high order statistical(HOS)characteristics of the channel capacity of a typical D2D communication pair under Rayleigh channel.Firstly,due to the computational complexity of higher-order statistics,none of the existing studies consider the impact of interference equipment.This paper uses the Poisson Point Process to model the interference D2D users,and assumes that all D2D users are equipped with multiple transmit and receive antennas Secondly,this paper proposes a new calculation method and derives the double integral expression of the HOS of channel capacity.In addition,using this expression,this paper further derives the expressions of the HOS of channel capacity for D2D users with three different receiving modes:maximum ratio combining,zero forcing,and transmitting antenna selection.Finally,by analyzing the impact of the test link transmitted signal to noise power ratio and path fading index on the amount of dispersion,fading figure,skewness and kurtosis,the channel quality and stability under the three methods are compared.Simulation results show that the transmit antenna selection scheme has the best channel quality and stability.It provides a reference for studying multi-interference ad-hoc D2D communication system under Rayleigh fading environment to study channel dispersion and achieve the transmission reliablility,and then to study spectrum aggregation technology.(2)In the cellular D2D communication system model,this paper analyzes the uplink outage probability when D2D shares spectrum with cellular users in a single hexagonal cell.Firstly,under the independent and identically distributed Rayleigh fading channel,D2D and cellular users are modeled by using stochastic geometry knowledge,respectively.D2D and cellular users adopt link gain mode selection scheme and full-channel inversion power control scheme.Secondly,using the Laplace transform of the general Poisson granular noise process,the expressions of the outage probability of the base station and the D2D receiver are derived respectively.Finally,the influences of the number of D2D users' antennas,maximum transmission power and channel inversion reception power on the outage probability are analyzed.Simulation results show that increasing the number of D2D user antennas and the maximum transmission power,and reducing the channel reversal received power can effectively reduce the outage probability.