Research On Spectral Efficiency And Energy Efficiency Of Distributed Antenna System With D2D Communication

With the development of various multimedia services,more and more users are pursuing high data rates and broadband multimedia services.In order to meet the explosive growth of wireless traffic and reduce greenhouse gas emissions,Spectral efficiency(SE)and energy efficiency(EE)are important ways to meet the needs of users to achieve green communication,thus It is critical to expand existing wireless infrastructure and deploy a new system.As one of the key technologies of the new generation communication network,Distributed Antenna Systems(DAS)has been widely studied by scholars at home and abroad.Distributed antenna systems have a excellent performance in increasing system capacity,expanding coverage,and improving energy efficiency.However,distributed antenna systems have some shortcomings due to their special structure,such as edge users have poor service quality,and it is difficult to suppress interference in the system,in order to provide reliable communication.We can take advantage of Device to Device(D2D)communication to compensate for deficiencies in distributed antenna systems,such as providing wireless coverage outside of cellular networks,reducing the burden on core networks,and providing high-speed communications.Therefore,this paper mainly studies the system performance of the distributed antenna system with D2 D communication.Firstly,it introduces the background of the topic,the research status of distributed antenna system and D2 D communication at home and abroad,and then mainly studies the optimization of spectral efficiency and energy efficiency of distributed antenna system with D2 D communication under different transmission modes,the main work contents are as follows:1)The optimal power allocation schemes are proposed to maximize the spectral efficiency and the energy efficiency of distributed antenna system with D2 D communication in orthogonal mode,respectively.Firstly,the D2 D selection algorithm is used to select D2 D pairs from the total users that satisfy the D2 D communication.Secondly,the method of sub-gradient iteration is used to optimize the spectral efficiency of the system,and the corresponding spectral efficiency maximization power allocation algorithm is proposed.For maximizing energy efficiency,the objective function of the optimization problem is non-convex,which is very complicated to calculate.By using the fractional programming theory,the non-convex objective function in fractional form is transformed into an equivalent convex objective function with subtraction form,the objective function is solved by sub-gradient method and Lagrangian multiplier method.Thereby an optimal power allocation scheme that maximizes energy efficiency is obtained.2)The optimal power allocation schemes are proposed to maximize the spectral efficiency and the energy efficiency of distributed antenna system with D2 D communication in reuse mode.There is interference between the cellular users and the D2 D pairs in the reuse mode.The D2 D pairs selection algorithm is also used to distinguish D2 D users from cellular users and establish the corresponding mathematical model.For maximizing spectral efficiency,we use function recombination to transform the objective function into an optimization problem with a Difference of Convex Function(D.C.)structure.Secondly,the optimization problem with D.C.structure is transformed into the traditional convex optimization problem by using Concave Convex Procesure(CCCP)algorithm,and the inner point method is used to obtain the optimal power allocation scheme.In terms of maximizing energy efficiency,we use the Dinkelbach algorithm to transform the original objective function,then convert it into a D.C.problem,and use the CCCP algorithm and the interior point method to find the optimal solution,Finally,the corresponding power allocation algorithm is proposed3)For the distributed antenna D2 D communication system and distributed antenna systems,We analyzed the spectral efficiency and energy efficiency of the two systems.It can be known from the simulation results that the optimal power allocation algorithms for maximizing spectral efficiency and energy efficiency of the distributed antenna system with D2 D communication proposed in this paper is superior to the distributed antenna systems under the same conditions.Finally,the correctness and effectiveness of the proposed algorithm are verified.