Research On Interference And Coexistence Of LTE System

In the progress of the standardization of the3rd generation partnership project (3GPP) long term evolution (LTE) system and the deployment of wireless resource, the LTE system and other wireless conmmunication systems may be deployed in the same geographical area in adjacent frequency channels. The interference problem between the LTE system and other systems is quite important. It is urgent to eliminate adjacent channel interference and to ensure the coexistence between the LTE system and others.The major contributions of this dissertation include:The interference and coexistence between the LTE system and the digital broadcasting television system is analyzed. The Monte Carlo simulation method is used, and we got some required ACIR values and reasonable measures to keep the two systems operating properly. The contribution of this part can be two-folded. Firstly, in the research of adjacent channel interference from the LTE system to the digital broadcasting television system, an improved simulation method is proposed. This method considers the deployment of the LTE system and the deployment of the digital broadcasting television system as two separated parts. Hence, it can considerably reduce the simulation complexity. Secondly, in the research of adjacent channel interference from the digital broadcasting television system to the LTE system, different offset distances between the two systems are considered. It includes two scenarios, where the digital broadcasting television system transmitter is located at the center of the LTE cell or the edge of the LTE cell. The scenario of deploying the digital broadcasting television system transmitter at the LTE system’s cell edge can achieve a relative good performance.Then, the interference and coexistence between the LTE system and the wireless local area networks (WLAN) system is analyzed. The Monte Carlo simulation method is also used. The required ACIR values and reasonable measures to keep the two systems operating properly are obtained. As can be seen from the simulation results, the interference situation from WLAN to LTE uplink is very severe and reasonable methods should be taken. The interference situation from WLAN to LTE downlink is acceptable without additional isolation operations.