Flex-NOMA: Exploiting Buffer-Aided Relay Selection for Massive Connectivity in the 5G Uplink
Date
2019Author
Nomikos, NikolaosMichailidis, Emmanouel T.
Trakadas, Panagiotis
Vouyioukas, Demosthenes
Zahariadis, Theodore
Krikidis, Ioannis
ISSN
2169-3536Source
IEEE AccessVolume
7Pages
88743-88755Google Scholar check
Metadata
Show full item recordAbstract
The success of fifth generation (5G) mobile network and its long-term evolution (LTE) relies on enabling demanding services with massive connectivity requirements, including Internet of Things (IoT) nodes, mobile devices, or unmanned aerial vehicles (UAVs). Towards this end, non-orthogonal multiple access (NOMA) schemes allow multiple users and devices to communicate using the same temporal and spectral resources. In this context, buffer-aided (BA) relay selection can significantly enhance the quality and reliability of communication, through increased diversity. So, in this paper, we employ BA relay selection in the uplink of the NOMA networks where users and devices coexist and demand access to the wireless resources. The presented relay selection policy, namely flex - NOMA, facilitates simultaneous transmissions from multiple sources to multiple relays, exploiting channel state information at the reception, and dynamic decoding ordering by the relays performing successive interference cancellation (SIC). The theoretical analysis and performance evaluation results are provided and comparisons, in terms of outage probability, average sum-rate and average delay show that flex - NOMA offers improved performance without incurring high complexity and coordination overheads.