He Study Of The Lte Downlink Transmittionbased On Softwaredefined Radio

The rapid development of wireless communication technology has promoted the unceasing emergence of new technology and standard. And during the technical innovation, the coexistence of a variety of communication systems is inevitable. However, due to the different method of modulation, transmission and access, it’s difficult for equipment with different communication modes and specifications to achieve compatibility and interconnection. All of these suggest that the existing communication system mainly depending on hardware cannot meet the requirements of the4th generation mobile communication which features personal communications. Software Defined Radio (SDR) has been regarded as the key technology to solve this problem according to its nature of openness, universality and the software implementation. And as the arrival of4G footsteps, it has caught the attention of researchers and developers from all around the world. Furthermore, with the development of Long Time Evolution plan, SDR technology will become more and more important.First, the Software Defined Radio (SDR) principles and key technologies are analyzes in this paper. In addition, internal structure and working principle of open source software GNU Radio and hardware USRP are summarized.Second, the technologies related to realize this communication system. are analyzes and summarized. Besides, the structural characteristics function and implementation principle in MAC, RLC layers are summarized.Finally, based on software radio technology and LTE-related principles, a complete solution of the LTE downlink system is designed which involves the general idea, software and hardware implementations. GNU Radio and USRP are used as the software and hardware tools respectively to achieve. LTE downlink data communication. And also, the key issues of system implementation process and its solutions are given in this paper; Ultimately, the software-defined radio development platform is built up and tested in the Linux environment. By modifying the hardware interface, the hardware USRP and software systems are interconnected successfully. The functional testing proves that this LTE downlink system can achieve data transmission and reception.