Matrix-Based Cellular/D2D Mixed-Network System Simulation

As the evolution of the LTE-Advanced system, the transmission method that employs base-station as its comimmication center in cellular system highlights its limitations gradually. Besides, the shortage of wireless spectrum resources in mobile communication impedes its further growth, how to utilize the limited spectrum resources to achieve the high capacity and high bit-rates communication becomes a focus of research in industry. The Device-to-Device (D2D) technique, which has become one of the key technologies to improve the coverage and enhance the regional capacity, will be introduced into LTE-Advanced system. The D2D technique enables users to communicate directly without help of base-station, which not only meet the needs of the terminal, but also alleviate the load pressure of the base-station.D2D communication shares spectrum resources with cellular system, i.e. using space-diversity technique to improve the spectral efficiency. At some scenarios with larger user density, the D2D communication has advantages of enhancing network throughput, saving the power of terminal equipment and so on, which draw much attention in recent years. D2D communication can flexibly reuse the temporarily available spectrum, which is based on cognitive radio technology. On the other hand, how to effectively control the mutual interference between the D2D link and cellular link has always been a key point in the study of the industry.This paper establishes a hybrid scenario in accordance with the3rd Generation Partnership Project (3GPP), which contains numerous cellular terminals and D2D terminals. The D2D terminals are authorized to reuse the up-link frequency resource of the cellular system. This paper develops a system-level simulation platform, considering the factors such as propagation loss, path-loss compensation and so on. It provides a tool to observe how the interference between cellular link and D2D link affect the performance of hybrid system. Besides, it also includes two types of interference avoidance schemes which are used to implement the intelligent reuse of resources and analyzes the performance (mainly throughput) of the system by using the Monte-Carlo simulation method. The simulation platform is based on the Matlab, because that it has strong advantages on matrix calculation. Therefore storing simulation parameters as matrix can be helpful to effectively verify the performance of the hybrid system.