Multi-User Auxiliary Signal Superposition Transmission (MU-AS-ST) for Secure and Low-Complexity Multiple Access Communications

Beyond 5G (B5G) and future 6G systems are expected to serve a massive number of interconnection links between base stations and Internet of Thing (IoT) devices. Thus, it is critical to develop new effective multiple access techniques, which can serve the demands of this massive number of connections. In this regard, power domain non-orthogonal multiple access (PD-NOMA), which was studied extensively by both academia and industry, was perceived as a potential candidate to the problem of serving more devices while having limited resources; however, the PD-NOMA design was eliminated from the list of the 17th release of 3GPP work items. Even though PD-NOMA proves efficient compared to OMA systems in certain scenarios and under specific conditions, it suffers from many issues including: low reliability due to having inter-user-interference, security vulnerability to both internal and external eavesdropping, the complexity of the transceiver due to the use of successive interference cancellation (SIC), and the inapplicability in power-balanced scenarios, where the superimposed users have the same distance from the base station. To address the aforementioned problems related to PD-NOMA, in this work, we propose and develop a novel new alternative non-orthogonal transmission design through the use of specially designed auxiliary signals superimposed with the users’ data. The proposed design is termed and coined as MU-AS-ST (Multi-User Auxiliary Signal Superposition Transmission) and is featured with a very simple transceiver design, where all the processing is done at the base station, thus freeing the receiver from any complex processing. The offered advantages by the proposed design make from it an ideal candidate for low-power and processing-limited devices such as IoT applications.