Analysis of STBC-aided energy harvesting cooperative NOMA for Internet of Things

Purpose This study aims to demonstrate the possibility of integrating a space-time block code (STBC) transmission scheme in a cooperative non-orthogonal multiple access (CNOMA) system with an energy harvesting (EH) relay. Specifically, the authors incorporate the STBC scheme at the source and the relay nodes while considering the existence of direct and indirect paths in the system. This study aims to provide a new approach to augmenting the diversity gain with a guaranteed sustainable network operation of the Internet of Things (IoT) devices, which are designated as the destination nodes in the proposed system. Design/methodology/approach To examine the effectiveness of the proposed system, the authors adopt a closed-form approach in developing numerical expressions used in gauging the system performance. These include the exact and asymptotic outage probability (OP) analysis, throughput performance, energy efficiency and diversity gain. Further, the authors use MATLAB software to perform the numerical computations. Findings This study compares the results from the numerical analysis with several benchmark schemes. The results obtained demonstrate the superiority of the solution in comparison to the benchmarks. This is evident from the OP of the destination user equipment, which is improved by approximately 38% and 64% when compared with the conventional EH STBC-aided CNOMA and the case without EH, respectively. Originality/value This study provides an innovative insight into addressing the foreseeable problem of spectral efficiency, limited data connectivity of IoT devices and energy-constrained operational lifetime of fifth-generation (5G) and beyond 5G networks. Using the STBC transmission scheme and EH in CNOMA systems will support the realization and goals of these communication systems. These goals include seamless connectivity of billions of IoT devices, enhanced achievable data rate and energy-efficient and sustainable network operation.