A Simple LTE-R Resource Allocation Scheme For Relay-assisted Railway Communications

With the continuous development of smart phone technology and Wireless mobile communication technology,People also pay more attention to the Internet experience during the journey when taking High-speed railway.At the same time,the passenger transport industry also has an increasing demand for passengers to maintain access to the Internet and be able to make high-quality calls during the journey.Therefore,high-speed railway communication network has been widely studied and discussed.How to ensure smooth switching of communication network in the coverage of each base station and how to meet the user’s quality of service(Qo S)in high-speed railway communication network has become an urgent problem to be solved.Under normal circumstances,the mobile user(UEs)communicates directly with the base station(BS),but the actual Qo S is greatly reduced due to the path loss(PL)and shadow wing effect of the wireless signal during transmission.As an alternative solution to this problem,the Third Generation Partnership Program(3GPP)supports relay communications in the Long Term Evolution Advanced(LTE-A)version 10 standard.In order to enhance wireless cellular coverage and overcome medium to high vehicle penetration path loss(VPL),it is proposed to add mobile relay(MRs)to high-speed railway communication system.Many studies have shown that the performance of mobile trunk-assisted transmission is much better than that of fixed trunk-assisted transmission and direct transmission.By introducing two antennas connected together by cable,connecting the trunk inside and outside the vehicle(and thus connecting the space inside and outside the vehicle to form a channel),the vehicle penetration path loss is negligible.The external antenna communicates with the base station,and the internal antenna communicates with the mobile user in the car.Under this premise,how to allocate LTE resources has become the primary task.The research work carried out in this paper is as follows:1)A low complexity resource allocation scheme based on the Hungarian algorithm is proposed,which reduces the dimension of the matrix by means of the cost matrix,aiming to maximize the service for the customers in the carriage while using the least power consumption.Compared with the optimal value returned by an extensive search algorithm[12]over the entire existing solution space,the scheme proposed in this paper can produce a near-optimal solution.As a key advantage of the scheme,the computational complexity of the scheme is greatly reduced compared to the optimal solution,resulting in a faster LTE-R resource allocation process that is better than the optimal benchmark.When the network topology and wireless environment can change dramatically in a short period of time(100-500 milliseconds),this advantage is well suited to the real-time business needs of users traveling by high-speed rail(HSR).In short,the communication service latency of passenger electronic devices in high-speed rail is lower,and the Internet experience is more perfect.2)In order to verify our proposed scheme,we have carried out a large number of simulations.Compare the number of mobile users served by the two algorithms with a given Total Trasmit Power,the respective Processing Latency of the two algorithms for serving different numbers of mobile users,and the different Total transmission power given In order to verify the effectiveness and efficiency of the proposed LTE resource allocation scheme for relay-assisted railway communication,the number of mobile users served by the algorithm in the case of Trasmit Power.