Design and Performance Evaluation of Cooperative Scheme for Non-Orthogonal Multiple Access Systems

Abstract

Non-orthogonal multiple access (NOMA) has recently attracted much attention for its potential to improve network spectral efficiency and cell-edge user throughput It allows a base station (BS) to serve multiple users using same resource by combining superposition coding with successive interference cancellation (SIC) in conjunction with power-domain multiplexing This is different from orthogonal multiple access schemes such as orthogonal frequency division multiple access (OFDMA) and time division multiple access (TDMA) Some recent work combines NOMA with different techniques for further throughput improvement Particularly cooperative NOMA (C-NOMA) has been proposed by employing cell-center user as the relay to forward signal to cell-edge user However early research is conducted assuming perfect SIC and ignoring path loss that lead to somewhat optimistic results In this work a low-complexity user grouping and pairing scheme is presented rstly Secondly we design a cooperative scheme that decides whether direct transmission or cooperative relaying is bene cial to the cell-edge user Finally we derive the symbol error probability of quadrature phase shift keying (QPSK) modulations for a given user pair considering channel impairments including Rayleigh fading and path loss Simulation results verify the accuracy of our analysis and demonstrate the performance of C-NOMA under practical settings in comparison with NOMA and TDMA

Date of Award	2015 Aug 24
Original language	English
Supervisor	Kuang-Hao Liu (Supervisor)