Exploiting Intentional Frequency Offset in NOMA-OFDM Systems: From Basic to Practical

Son, Joohyun; Lee, Hakkeon; Jung, Insik; Hong, Daesik

doi:10.1109/twc.2023.3247986

Cited by 3 publications

(3 citation statements)

References 21 publications

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“…Because the weaker user's signal is subtracted, it is treated as interference when detecting the strong user's signal. Thus, if the weaker user's signal is not properly decoded, the stronger user's signal may also not be identified correctly [14].…”

Section: Introductionmentioning

confidence: 99%

“…As a result, non-idealities such as the fading channel effect and carrier frequency offset (CFO) caused by oscillator frequency mismatch reduce the symbol error rate (SER) performance for signal detection in downlink power domain multi-user NOMA-OFDM [2,4,9,10,14,15]. As a multi-carrier multiple-access technique, it has a high peak-to-average power ratio (PAPR).…”

Section: Introductionmentioning

confidence: 99%

“…This causes NOMA-OFDM symbol dispersion in the time domain. The non-linear radio frequency (RF) impairments mainly consist of carrier frequency offset (CFO) and non-linear distortion (NLD), which cause Inter-user NOMA-OFDM spectral dispersion, inter-carrier interference (ICI), and inter-user interference (IUI) [2,14]. In this way, the combined linear channel impairment and non-linear RF impairment lead to imperfect SIC.…”

Section: Introductionmentioning

confidence: 99%

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

Singh,

Saha

2023

Eng. Res. Express

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Non-orthogonal multiple access-based orthogonal frequency division multiplexing (NOMA-OFDM) is a promising waveform-based multiple access technology for future wireless networks for multiple-user symbol transmission (MUST) in the same time-frequency resource block. However, it differs in the power domain, enhancing its spectrum efficiency. This is essential to meet the high data rate required for ever-increasing connected devices and the Internet of Things (IoT). However, NOMA-OFDM systems suffer from impairments such as imperfect successive interference cancellation (SIC) caused by channel impairments like channel fading, carrier frequency offset, and non-linearity caused by non-linear power amplifiers. This paper identifies and addresses the key impairments mentioned in the NOMA-OFDM system and proposes DNN-based estimation in offline training and detection in online testing for downlink power domain multi-user NOMA-OFDM symbols. The reported 2 dB SNR gain compared to least square-SIC/minimum mean square error SIC-based methods is a significant finding and demonstrates the robustness of the proposed DNN-aided approach against various channel impairments.

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Section: Introductionmentioning

confidence: 99%