Non-Orthogonal Multiple Access (NOMA) for Cellular Future Radio Access

TLDR

NOMA superposes multiple users in the power domain, differing from LTE's orthogonal access, while using similar OFDMA or DFT‑spread OFDM waveforms. The paper proposes a NOMA concept for future cellular radio access to support the 2020s information society. The concept uses a successive interference cancellation receiver as the baseline to enable robust multiple access. System‑level evaluations show that downlink NOMA with SIC boosts capacity and cell‑edge throughput regardless of base‑station CQI, and extensions with NOMA/MIMO and IRC receivers can yield up to a three‑fold spectrum‑efficiency gain.

Abstract

This paper presents a non-orthogonal multiple access (NOMA) concept for cellular future radio access (FRA) towards the 2020s information society. Different from the current LTE radio access scheme (until Release 11), NOMA superposes multiple users in the power domain although its basic signal waveform could be based on the orthogonal frequency division multiple access (OFDMA) or the discrete Fourier transform (DFT)-spread OFDM the same as LTE baseline. In our concept, NOMA adopts a successive interference cancellation (SIC) receiver as the baseline receiver scheme for robust multiple access, considering the expected evolution of device processing capabilities in the future. Based on system-level evaluations, we show that the downlink NOMA with SIC improves both the capacity and cell-edge user throughput performance irrespective of the availability of the frequency-selective channel quality indicator (CQI) on the base station side. Furthermore, we discuss possible extensions of NOMA by jointly applying multi-antenna/site technologies with a proposed NOMA/MIMO scheme using SIC and an interference rejection combining (IRC) receiver to achieve further capacity gains, e.g., a three-fold gain in the spectrum efficiency representing a challenging target for FRA.