One major issue in the design of active Radio Frequency IDentification (RFID) systems is the need for increasing the coverage, since it is essential for many applications to have a large communication range. In this paper, we propose an active RFID system based on ISO/IEC 18000-7, an energy efficient RFID standard, in which a two-hop relay system is utilized. It is shown that our proposed two-hop relay system can increase the coverage of the reader. In order to increase the efficiency of the two-hop system, we propose a Participation ID (PID) two-hop system. In our modified method, active tags do not participate more than once in a collection round. Hence, the power consumption of active tags is decreased and the throughput of the system is increased. We also evaluate the performance improvement of our modified method in comparison to the existing two-hop relay systems through simulation.