Research On Radio Frequency Characteristics And Testing Of User Equipment In Td-Lte-a System With Carrier Aggregation

In order to comply with the development tendency of broadband and high speed in mobile communication system, the international standardize organization3GPP is actively promoting the standardization of LTE/LTE-A, a new generation of mobile communication systems. As an important part of the process, TD-LTE/TD-LTE-A system which led by China and use the technology of Time Division Duplex (TDD), also received much concern.As the core part of the mobile communications, the User Equipment’s (UE’s) quality plays a key role in the performance of a communications system. Launching the research of TD-LTE-A UE test technology is helpful to guide the UE product development, and improve the performance and quality of TD-LTE-A UE; thereby the TD-LTE industry can achieve sustainable development. By aggregating multiple disperse carriers, Carrier Aggregation (CA) technology extended signal transmission bandwith, improved spectral efficiency, and helped to achieve high-speed transmission, was identified as the key technologies for LTE-Advanced.This paper focused on the Radio Frequency (RF) characteristics of UE receiver in TD-LTE-A system with carrier aggregation and conducted in-depth research on them.Firstly, the specifications of RF characteristics and conformance testing of UE receiver in TD-LTE-A system in3GPP were studied, and the related concepts and parameters were introduced.Secondly, according to the Radio Frequency requirements of3GPP specifications, a simulation platform was set up for TD-LTE-A UE receiver, four typical test cases in UE receiver RF conformance testing i.e. adjacent channel selectivity, in-band blocking, out of band blocking and narrow band blocking, were analysed by performing simulations, and the factors that affect the test results were studied. This work provides a basis for the improvement of the test specifications as well as the analysis of the test results.Finally, on the basis of the study and simulation of the receiver RF characteristics and test cases, several factors that affect the anti-interference performance of UE with CA were concluded, which include the impact of frequency spacing between CA signal and the interference signal on the interference level, the relationship between the interference-resistance capability of LTE/LTE-A UE and the parameters of the receiver filter, and the impact of receive diversity on UE receiver RF testing. All the theoretical analyses were verified by simulations, and the research will be the reference for the standardization of LTE/LTE-A and the UE’s design.