Embedded CR Enabled Flexible Rate Splitting for Massive Access

Smart cities have entered into a new era with the widespread commercialization of 5G. As a key supporting technique for smart cities, Internet of Everything (IoE) puts forward higher requirements for real-time data and massive access. In this article, we propose a novel embedded cognitive radio (CR) enabled rate splitting multiple access (ECR_RSMA) solution, in which the secondary user (SU) can access more than one idle spectrum holes of the primary users (PUs) by spitting the data rate without causing additional interference to the PUs. To ensure the quality of service (QoS) of each user, a composite successive interference cancelation (SIC) decoding scheme is specially designed, and the channel prediction algorithm is employed to combat the channel aging effect. The effectiveness of the proposed ECR_RSMA is verified through computer simulations. Compared with the state-of-the-art multiple access schemes, such as CR_NOMA, the proposed solution can significantly improve the performance in terms of the spectrum efficiency as well as the outage probability.