This thesis presents the constructing, integrating and testing processes of the 4th generation LTE systems. It describes the physical background and the main parameters of the LTE technology, and shows the technical innovations compared to the second and third generation mobile networks. It expounds the main equipments of the base transceiver station and its functions. It details the phases of the system building, both from the subcontractor’s and the mobile service provider’s side, and shows the errors and unexpected problems along the whole procedure, and offers solutions for these problems. Finally, it walks us through the testing of the integrated system, mentioning multiple test types of the data transfer, the test requirements of the mobile service providers, the tested parameters, and the upcoming problems and its causes and solutions. At the end of the thesis the required cell plans for the LTE system, the implementation of the integration and the testing of the service are demonstrated by a real life example.