On the Channel Estimation Performance of NOMA Systems: Experimental Implementation of Real-Time Downlink NOMA-OFDM

Angjo, Joana; Tuncer, Mehmet Mert; Akertek, Ege; Alakoca, Hakan; Başaran, Mehmet; Durak–Ata, Lütfiye

doi:10.1109/blackseacom48709.2020.9234965

Cited by 7 publications

(6 citation statements)

References 22 publications

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“…The beam spread of 5.7 0 is measured after diffuser with a beam size of 20 cm diameter at user 2. The NOMA decoding using SIC algorithm [23] is implemented offline in MATLAB to decode and characterize the received waveforms.…”

Section: Methodsmentioning

confidence: 99%

Demonstration of gigabits-per-second two-user NOMA in laser-based indoor optical wireless communication

Ramachandrapura,

Ahmad,

Raghunathan

2024

Next-Generation Optical Communication: Components, Sub-Systems, and Systems XIII

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We experimentally demonstrate a two user non-orthogonal multiple access (NOMA) based indoor optical wireless communication link with gigabit-per-second data throughput. MATLAB based simulations are carried out to characterize the indoor power profile and bit-error rate (BER) performance. The experimental implementation consists of directly modulating a near infrared laser to transmit the superposition coded (SC) NOMA symbols with signals received using two separate receivers, which denote the two spatially separated users. The received signals captured using an oscilloscope are decoded using successive interference cancelation (SIC) technique implemented offline in MATLAB. The experimentally measured channel responses are used in simulations to compare the experimental and simulation results, showing good agreement between the two. Optical communication is demonstrated with overall data throughput of 1.02 Gbps with high fidelity interference cancellation. The data-rates achieved here are the highest reported for conventional NOMA implementation in optical wireless systems.

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Section: Methodsmentioning

confidence: 99%

Demonstration of gigabits-per-second two-user NOMA in laser-based indoor optical wireless communication

Ramachandrapura,

Ahmad,

Raghunathan

2024

Next-Generation Optical Communication: Components, Sub-Systems, and Systems XIII

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“…En [5] los autores presentan un análisis del rendimiento de la estimación de canal con una implementación real de un sistema NOMA-OFDM en el enlace de bajada. Para la estimación de canal utilizan subportadoras piloto que permiten determinar el estado de canal en ciertas subportadoras para luego, usando interpolación, obtener el estado del canal en el resto de subportadoras.…”

Section: Estado Del Arteunclassified

“…La técnica NOMA puede dividirse en 2 tipos principales los cuales son NOMA en el dominio del código y NOMA en el dominio de la potencia. En el primero se multiplexa señales de distintos usuarios mediante secuencias de expansión con correlación cruzada no ortogonal [5], en cambio en el segundo tipo se realiza asignaciones de distintos niveles de potencia según sea el caso, el cual dependerá de las condiciones de los canales debido a que múltiples usuarios tendrán acceso a las redes en el mismo instante, por el mismo canal de frecuencia o con el mismo código [11].…”

Section: Nomaunclassified

Análisis de la técnica NOMA-OFDM en un canal multitrayecto y usando estimación de canal

Picuasi

Chisaguano

2022

RITI

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NOMA (Non-Orthogonal Multiple Access) is a non-orthogonal access technique that can increase spectral efficiency and is considered a candidate technology for 5G. NOMA-OFDM combines the non-orthogonal access of NOMA with OFDM, which is widely used due to several advantages such as its high spectral efficiency. Channel estimation is an essential process in a NOMA-OFDM system, so in this paper a channel estimation scheme with preamble for the downlink is proposed considering a multipath channel and the LS (Least Square) technique. The analysis of the results is performed based on graphs of BER (Bit Error Rate) vs Eb/N0 (Energy per bit to noise power spectral density ratio) of the simulation implemented in Matlab and shows that channel estimation is possible with the LS method with the advantage that it is a simple technique although it produces a degradation of approximately 3 dB in the BER compared to the ideal case of perfect estimation. In addition, the results show that the selection of the injection factor is very important for the performance of the users to be adequate.

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“…To decrease the influence of phase noise in WiFi NOMA systems, [31], [35] extend their NOMA WiFi prototype to enable constellation rotation. The channel estimation and channel quantization impacts on NOMA OFDM have been investigated in [33] with varying pilot-to-data ratios. It reflects that with long channel estimation pilots the BER performance can be better.…”

Section: Prior Experimental Validations Of Nomamentioning

confidence: 99%

Over-the-Air Implementation of NOMA: New Experiments and Future Directions

Zhang

Vaezi

2021

IEEE Access

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Non-orthogonal multiple access (NOMA) is widely recognized to increase the number of users and enhance the spectral efficiency in fifth-generation (5G) wireless networks and beyond. NOMA is still in the theoretical analysis and simulation phases and fewer experimental works are reported to date. In this paper, we design and implement NOMA in software-defined radio, and evaluate its performance. This includes the real-time realization of the key components of NOMA, i.e., superposition and successive interference cancellation. The main novelty of this paper is to introduce constructing superimposed signals with varying symbol rates to enlarge the achievable rate region of the experimented NOMA. By applying varying symbol rates, the set of possible transmission rate pairs enlarges and we can reach higher data rates compared to existing modulation and coding schemes (MCS). We also propose an algorithm to efficiently find the rate pairs. Simulations and experiments demonstrate that NOMA with a varying symbol rate not only can reach higher data rates than orthogonal schemes such as time division multiple access, but it can also outperform existing MCS-based methods which have a fixed symbol rate. The experiments also show that there is a noticeable gap between NOMA in theory and practice. In addition to the new NOMA experiments, we review the state-of-the-art in experimental NOMA. We also discuss several directions for future experiments that can help bridge the gap between theory and practice and bring NOMA to practical communication systems.

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On the Channel Estimation Performance of NOMA Systems: Experimental Implementation of Real-Time Downlink NOMA-OFDM

Cited by 7 publications

References 22 publications

Demonstration of gigabits-per-second two-user NOMA in laser-based indoor optical wireless communication

Demonstration of gigabits-per-second two-user NOMA in laser-based indoor optical wireless communication

Análisis de la técnica NOMA-OFDM en un canal multitrayecto y usando estimación de canal

Over-the-Air Implementation of NOMA: New Experiments and Future Directions

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