Analysis And Implementation On L3Subsystem Of TD-LTE Femto Upper Software

3GPP Long Term Evolution, as the latest commercial technology of communication, has higher speed and more flexible method of resource allocation. Thus equipment manufacturers and operators have paid attention to this new technology. LTE is an evolution of the GSM/UMTS standards. LTE aims to increase the capacity and speed of wireless data networks using new DSP techniques and modulations that were developed around the turn of the millennium. The emergence of femto technology provides a new solution for indoor coverage.The femto technology is becoming a hot field of mobile communication technology as it costs lower in network building and is more flexible and more accurate in coverage. Femto system is a flat system architecture and it is in line with the evolution of mobile network. This technology meets the network requirements. Therefore, the combination of LTE system and Femto technology is the best way to solve system expansion and indoor coverage.This paper is based on the project’Upper-Layer Protocol Software of TD-LTE Product Development’. It is based on the TD-LTE standard and3GPP protocols. The aim of this project is to implement enterprise-class TD-LTE system and to achive a certain scale commercial.In combination with the project, this paper first introduces the TD-LTE Femto network architecture and related network elements and interfaces, and then analyzes the Femto system architecture, component modules of the upper-layer system. L3subsystem is one of these modules and this paper focuses on this subsystem. Then this paper introduces the user plane and control plane protocol stack of the whole system. This paper then pays attention to the upper-layer protocols and various functions of the modules, expounds the L3subsystem module design and message model. The key technologies are discussed and the detailed design is given in this paper.Based on the development of L3subsystem, this paper deals with the function and stability by unit tests, integration tests and real tests.According to these tests, the L3subsystem is verified to be correct.This system can complete the basic signaling process successfully and achieve high data transfer rate.