System Architecture Of D2D Veritication Platform Based On SDR And Real-Time Processing Technology

With the rapid development of wireless communication technology, a variety of new standards and new technologies continue to emerge. In order to meet the growing demand for mobile Internet local service, Device to Device (D2D) technology is introduced to the next generation of mobile communication technology, by which terminals can reuse the spectrum of cellular networks to communicate with others directly, instead of forwarding by the base station. For the terminal is concerned, D2D technology can provide higher-rate and lower-power transmission services than traditional cellular communication; and for the cellular networks, D2D technology can reduce the load for the base station, and improve the efficiency of resource utilization and the quality of cell coverage.In recent years, D2D technology has become a hot research field of mobile communication. In this paper, we firstly propose a set of relatively complete, achievable D2D communication scheme, and then develop an SDR-based D2D verification platform on the general-purpose processor (GPP), which can serve as an available and validated system for demonstration of D2D scheme and D2D-based local services. Systems based on GPP are flexible and easy to develop and maintenance.To achieve real-time D2D communication on non-real-time operating systems, however, real-time processing will be the great challenge facing the design.Content and innovation points of this paper are arranged as follows:Firstly, an innovative scheme in the LTE/D2D heterogeneous network is put forward, providing a feasible solution for the key steps. D2D terminals can achieve networking and access under current LTE cellular networks. With the help of the cellular network, D2D terminal can communicate with each other by sharing spectrum with the cellular network, while the interference is controllable.Secondly, a D2D experimental verification platform is achieved on GPP based Linux servers by realization, customization and integration of LTE physical layer and protocol layer, which supports a variety of IP based services, as well as real-time system status monitoring for the platform. It is experimentally verified that the D2D platform can realize D2D communication with transmission ability of more than17.52Mbps. Network self-orgnizing, routing and relaying is also supported by the system.Thirdly, in order to achieve real-time processing for the D2D verification platform on the non real-time operating system, a series of optimization is carried on system architecture design, performance of the software modules, and operating system environment. With parallelism enhanced by pipeline processing and SIMD, critical process like signal reception and resource managing, can be completed in real time.