With the emergence of various IoT applications, a large-scale IoT system is set to revolutionize the various industry. Massive machine type communication will play a crucial role in providing robust support to this system. However, in mMTC, implementing user access control to block malicious users remains a critical issue that needs to be addressed. To this end, this paper proposes a user access control scheme based on resource hopping multiple access (RHMA). This scheme utilizes the unique resource hopping patterns of different users to control user access. The controllability of these resource hopping patterns effectively prevents malicious users from intruding into the system. Moreover, the proposed user access control scheme is implemented in practice with USRP platform. The experimental results confirm the reliability and effectiveness of the proposed access control system.