Non-Orthogonal Multiple Access (NOMA) for 5G Networks

Kızılırmak, Refik Çağlar

doi:10.5772/66048

Cited by 69 publications

(44 citation statements)

References 9 publications

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“…Additionally, in OFDMA, the subcarrier separation must follow a certain frequency constraint in order to attain orthogonality. In NOMA, this separation is not applicable as all the bandwidth is utilized by all users [8,33]. The concept of NOMA is based on applying SC at the transmitter and SIC at the receiver, as shown in Figure 2.…”

Section: Appl Sci 2019 9 3022 4 Of 19mentioning

confidence: 99%

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Enhanced NOMA System Using Adaptive Coding and Modulation Based on LSTM Neural Network Channel Estimation

et al. 2019

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Non-orthogonal multiple access (NOMA) is the technique proposed for multiple access in the fifth generation (5G) cellular network. In NOMA, different users are allocated different power levels and are served using the same time/frequency resource blocks (RBs). The main challenges in existing NOMA systems are the limited channel feedback and the difficulty of merging it with advanced adaptive coding and modulation schemes. Unlike formerly proposed solutions, in this paper, we propose an effective channel estimation (CE) algorithm based on the long-short term memory (LSTM) neural network. The LSTM has the advantage of adapting dynamically to the behavior of the fluctuating channel state. On average, the use of LSTM results in a 10% lower outage probability and a 37% increase in the user sum rate as well as a maximal reduction in the bit error rate (BER) of 50% in comparison to the conventional NOMA system. Furthermore, we propose a novel power coefficient allocation algorithm based on binomial distribution and Pascal’s triangle. This algorithm is used to divide power among N users according to each user’s channel condition. In addition, we introduce adaptive code rates and rotated constellations with cyclic Q-delay in the quadri-phase shift keying (QPSK) and quadrature amplitude modulation (QAM) modulators. This modified modulation scheme overcomes channel fading effects and helps to restore the transmitted sequences with fewer errors. In addition to the initial LSTM stage, the added adaptive coding and modulation stages result in a 73% improvement in the BER in comparison to the conventional NOMA system.

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Section: Appl Sci 2019 9 3022 4 Of 19mentioning

confidence: 99%

“…The same process is followed by the second strongest user. This process is repeated iteratively until the desired signal is decoded [8,28,34]. The SIC method works in an iterative way, imposing lower hardware complexity at the receiver in comparison to conventional multi-user detection schemes.…”

Section: Successive Interference Cancellation (Sic)mentioning

confidence: 99%

Enhanced NOMA System Using Adaptive Coding and Modulation Based on LSTM Neural Network Channel Estimation

et al. 2019

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“…From (26), the energy efficiency depends on ζ, B, and Γ total . For a certain B and Γ total , the higher spectrum efficiency leads to the increased energy efficiency [29]. Due to the narrow guard bands without CP insertion, the FBMC system achieves an improved spectrum efficiency, which simultaneously obtains greater energy efficiency compared with other waveforms.…”

Section: Analysis Of the Spectral Efficiencymentioning

confidence: 99%

SS‐OFDM: an enhanced multicarrier transmission scheme based on variable granularity spectrum allocation for 5G

et al. 2018

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“…A continuous enhancement in the technology has been observed with the passage of time and demand of the modern age. Requirement of more data rate, higher spectral efficiency, enhanced user fairness, extremely low latency, massive connectivity, better QoS, low cost and other parameters of future technology, demands conventional OMA techniques such as TDMA, FDMA (including OFDMA), and CDMA transition to NOMA [1], [2]. Quality of service has been decreased while proceeding from 1G to 3G due to increase in the number of users which resulted in self interference.…”

Section: Introductionmentioning

confidence: 99%

“…For LTE uplink transmission SC-FDMA has been used due to several drawbacks of OFDM including power loss in self-interference, spurious radiation and inter-modulation distortion [2]. For meeting high technological demands, Non Orthogonal Multiple access (NOMA) has been proposed as an aspirant of imminent 5G technology [1]. It can provide a number of benefits including user fairness, extremely high speed, best spectral efficiency, better latency, superior ergodic sum rate and massive connectivity etc.…”

Section: Introductionmentioning

confidence: 99%

Non-orthogonal multiple access: basic interference management technique

Khan¹,

Jayakod²,

Chen³

2018

IJET

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Non Orthogonal Multiple Access (NOMA) is a technique that offers spectral efficiency, Quality of Service (QoS), user fairness, low latency, high data rate, and overall better performance as compared to Orthogonal Multiple Access (OMA). The main feature of NOMA is the efficient utilization of spectrum due to increasing demand of data rate. We have introduced a new technique known as MNOMA (Modulation based NOMA) which will help in reducing the interference and complexity of signals decoding, not only in uplink but downlink as well. We have achieved the target of proposed technique by working on superposition coding (SC) of the system. In NOMA interference between users is certain due to removal of orthogonality in spectrum. The problem of interference has been tackled with superposition coding and a number of SIC’s (Successive Interference Cancellation) performed on the receiver's end. With MNOMA technique we have tried to reduce the complexity of system by integrating the basic orthogonality in the transmitter instead of spectrum. In this paper, we have shown the reduced expression of data rate for the proposed technique, which shows reduced complexity of the system in terms of SIC, Symbol Error Rate (SER), and better data rate of the proposed technique as compare to conventional OMA.

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Non-Orthogonal Multiple Access (NOMA) for 5G Networks

Cited by 69 publications

References 9 publications

Enhanced NOMA System Using Adaptive Coding and Modulation Based on LSTM Neural Network Channel Estimation

Enhanced NOMA System Using Adaptive Coding and Modulation Based on LSTM Neural Network Channel Estimation

SS‐OFDM: an enhanced multicarrier transmission scheme based on variable granularity spectrum allocation for 5G

Non-orthogonal multiple access: basic interference management technique

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