Space–time block coded non-orthogonal multiple access for performance enhancement of underwater acoustic sensor networks

Abstract

In this letter, we propose space–time block coded non-orthogonal multiple access (STBC-NOMA) for underwater acoustic sensor networks (UASNs) to improve reliability by exploiting transmit diversity and spectral efficiency. We derive mathematical expressions for ergodic rate, outage probability and energy efficiency. Results show that STBC-NOMA can combine the advantages of STBCs and NOMA, which significantly enhance the performance of UASNs, without the need for prior CSI status at the transmitter. Finally, we jointly optimize the signal frequency and power allocation coefficient for the STBC-NOMA scheme with respect to the transmission distance using pattern search algorithm, to further enhance the ergodic rate.

Keywords

• Non-orthogonal multiple access
• Space–time block codes
• Underwater acoustic sensor networks