Research On Network Planning And Optimization Of High-speed Railway Mobile Communication System Based On Distributed Antenna

In recent years,mobile communication devices have become more and more popular,and mobile communication devices such as mobile phones,tablet computers,and notebook computers have played an important role in people's daily lives and work.Mobile communication devices are interconnected through wireless network,so the demand for wireless network service quality is also increasing.As the most critical part of wireless network construction,network planning directly affects the service performance and quality of the wireless network.Many scholars are studying the network planning problems in the construction of wireless networks,and have proposed a variety of effective network planning solutions.The mobile communication in the high-speed railway environment is different from the general environment.Due to the high driving speed of the train and the characteristics of the closed compartment of the train,some problems that do not exist in the traditional communication environment are brought about: more frequent handovers,intensified Doppler frequency.Shift effect and higher penetration loss.For solving these problems,this paper proposes a network planning scheme based on distributed antennas: the concept of logical cells is proposed,and a certain number of antennas are deployed in each logical cell.These antennas all use the same frequency for communication,which can effectively reduce the number of handovers to improve network service quality.Further abstracting the network planning problem modeling into an optimization problem,which is under the premise of ensuring that the network transmission rate meets the minimum network speed limit,the total cost of the wireless network construction is reduced as much as possible,and the optimization problem is proved to be a NP-hard problem through a series of simplified conversion operations.In view of the NP-hard problem of network planning,this paper uses the improved cuckoo algorithm to solve this problem.Firstly,this paper analyzes the defects of the cuckoo algorithm in location update.In order to improve the performance of the cuckoo algorithm,this paper proposes the concept of the dimension cell and applies it to the location update of the algorithm.Compared with the original cuckoo algorithm,the improved cuckoo algorithm will update the cells according to the divided dimensions in the location update,and select the optimal solution in all the update cases as the next generation,which greatly reduces the mutual influence of the dimensions.Further this paper uses the CEC2014 test functions to verify the performance of the improved cuckoo algorithm,and the experimental results of the improved cuckoo algorithm are compared with the original cuckoo algorithm and other intelligent algorithms.The experimental results show that the improved cuckoo algorithm is superior to other comparison algorithms in solving accuracy and convergence speed.In order to further improve the accuracy of solving of the improved cuckoo algorithm to solve the network planning problem,this paper optimizes the important parameters of the improved cuckoo algorithm.According to the optimization problem of the network planning proposed in this paper,the important parameters of the improved cuckoo algorithm are determined through a large number of experiments.Based on the optimal value of the important parameters of the algorithm,and the improved cuckoo algorithm is used to simulate the network planning.The experimental results show that compared with the uniform network planning scheme,the network planning scheme based on the improved cuckoo algorithm has lower network construction cost.As the increase of the length of the railway section needed to build wireless network,the cost-saving effect of the network planning solution obtained by the algorithm becomes more apparent.In addition,compared with the simulation results of the original cuckoo algorithm and other modern intelligent optimization algorithms,the improved cuckoo algorithm also has the best solution performance.