Bit Error Rate Analysis of NOMA-OFDM in 5G Systems With Non-Linear HPA With Memory

Abstract

The orthogonal frequency division multiplexing (OFDM) and the non-orthogonal multiple access (NOMA) scheme are presented as promising techniques to meet the requirement of fifth-generation (5G) communication systems. Although much attention has recently been devoted to study these techniques, some scenarios have still been less explored. Considering that a fundamental part of any communication system is the use of power amplifiers, this paper presents an analytical evaluation of the bit error rate (BER) of NOMA-OFDM systems in the presence of a high power amplifier (HPA) with memory. Considering that the non-linear distortions generated by the HPA can be modeled using a polynomial model with memory, new theoretical expressions are developed to obtain the BER of the system. Specifically, exact BER expressions for a downlink NOMA-OFDM system with two users are presented and verified by Monte Carlo simulation results. The obtained numerical results demonstrate that the performance degradation of both users is highly dependent on the non-linear distortions, even when the successive interference cancellation (SIC) technique is performed perfectly.INDEX TERMS 5G, bit error rate, high power amplifier, non-linearity, non-orthogonal multiple access, orthogonal frequency division multiplexing.

Predistortion-Based Linearization for 5G and Beyond Millimeter-Wave Transceiver Systems: A Comprehensive Survey

“…1) Predistortion Facets for pNOMA Waveform: As mentioned above, the real-time integration of NOMA into modern PAs is in its infancy [259], [260], and much work needs to be investigated in this area. Specifically, the problem of high PAPR with a minimum bit-error rate per subcarrier brings some unique challenges in acquiring downlink pNOMA multiplexing signals.…”

“…Specifically, the problem of high PAPR with a minimum bit-error rate per subcarrier brings some unique challenges in acquiring downlink pNOMA multiplexing signals. In particular, the lack of reliable decoding at RX due to the nonlinear distortions of the downlink NOMA system maximizes the error propagation effects for the users sharing the same resources even if the perfect successive interference cancellation (SIC) technique is applied [260]. To accommodate successful SIC reception for the NOMA communication networks requires high computational power and processing time to run SIC algorithms, especially for the real-time MMW-mMIMO systems that demand iterative nonlinearity profiling for all transmitting users.…”

“…However, in pNOMA networks, there is a lack of research work or real applications discussing the integration of PD solutions to strengthen downlink transmissions. Although several high-PA standards based on analytical assessments of pNOMA schemes are recently proposed [259], [260]; there is a need for further exploration as the PA in modern TRX applications demands real-time adaption for a high value of PAPR. Afterward, in [262], the SIC stability in a downlink pNOMA enabled scenario that normalizes the designated power with superposition coding to allocated NOMA users has been proposed.…”

Low-complexity selective mapping technique for PAPR reduction in downlink power domain OFDM-NOMA

“…Few studies have been conducted on the performance of OFDM-NOMA systems in the presence of nonlinear distortion. In [9], nonlinear distortion was modeled as a residual hardware impairments (RHI) term, whereas in [10,11], HPA was modeled as a polynomial. Both the polynomial model and the RHI term are insufficient to investigate the effect of the nonlinear HPA on the performance of the OFDM-NOMA system.…”

Deep neural network based downlink power domain multi-user NOMA-OFDM signal detection

“…Furthermore, the SIC depends first on the perfect channel estimation and signal detection of the weak user. However, channel estimation for weak users suffers from channel impairments such as frequency-selective fading channel effects, carrier frequency offset (CFO), and non-linear distortion (NLD) [7,8,15]. The fading channel effect causes waveform-based pulse dispersion and inter-symbol interference (ISI).…”