Intelligent Interference Engineering for Secure Non-Orthogonal Multiple Access

Non-orthogonal multiple access (NOMA) is an effective approach to improving spectrum utilization and supporting massive connectivity for next-generation wireless networks. However, over a wireless channel, the superimposed NOMA signals are highly susceptible to eavesdropping, potentially leading to the severe leakage of confidential information. In this article, we unleash the potential of network interference and exploit it constructively to enhance secrecy in NOMA networks. Particularly, three different types of network interference, including artificial noise, a specifically-designed jamming signal, and inter-user interference, are well engineered to intentionally reduce information leakage while mitigating the effects on signal reception quality of the legitimate users, thus significantly enhancing the transmission security of NOMA. Furthermore, we propose potential interference engineering strategies in more advanced full-duplex NOMA, cognitive NOMA, and multi-cell NOMA networks, and discuss various open research problems and challenges, which could inspire innovative designs of interference engineering for secure NOMA communications.