scholarly journals On the Secrecy Rate of Downlink NOMA in Underlay Spectrum Sharing with Imperfect CSI

2021 ◽  
Author(s):  
Vaibhav Kumar ◽  
Mark F. Flanagan ◽  
Daniel B. da Costa ◽  
Le-Nam Tran
Keyword(s):  
Spectrum Sharing ◽  
Multiple Access ◽  
Estimation Error ◽  
Channel Estimation Error ◽  
Power Constraint ◽  
Secrecy Rate ◽  
Interference Constraint ◽  
Multiple Primary ◽  
Maximum Transmit Power ◽  
Underlay Spectrum Sharing

<div>In this paper, we present the ergodic sum secrecy rate (ESSR) analysis of an underlay spectrum sharing non-orthogonal multiple access (NOMA) system. We consider the scenario where the power transmitted by the secondary transmitter (ST) is constrained by the peak tolerable interference at multiple primary receivers (PRs) as well as the maximum transmit power of the ST. The effect of channel estimation error is also taken into account in our analysis. We derive exact and asymptotic closed-form expressions for the ESSR of the downlink NOMA system, and show that the performance can be classified into two distinct regimes, i.e., it is dictated either by the interference constraint or by the power constraint. Our results confirm the superiority of the NOMA-based system over its orthogonal multiple access (OMA) based counterpart. More interestingly, our results show that NOMA helps in maintaining the secrecy rate of the strong user while significantly enhancing the secrecy performance of the weak user as compared to OMA. The correctness of the proposed investigation is corroborated through Monte Carlo simulation.</div>

scholarly journals On the Secrecy Rate of Downlink NOMA in Underlay Spectrum Sharing with Imperfect CSI

2021 ◽  
Author(s):  
Vaibhav Kumar ◽  
Mark F. Flanagan ◽  
Daniel B. da Costa ◽  
Le-Nam Tran
Keyword(s):  
Spectrum Sharing ◽  
Multiple Access ◽  
Estimation Error ◽  
Channel Estimation Error ◽  
Power Constraint ◽  
Secrecy Rate ◽  
Interference Constraint ◽  
Multiple Primary ◽  
Maximum Transmit Power ◽  
Underlay Spectrum Sharing

<div>In this paper, we present the ergodic sum secrecy rate (ESSR) analysis of an underlay spectrum sharing non-orthogonal multiple access (NOMA) system. We consider the scenario where the power transmitted by the secondary transmitter (ST) is constrained by the peak tolerable interference at multiple primary receivers (PRs) as well as the maximum transmit power of the ST. The effect of channel estimation error is also taken into account in our analysis. We derive exact and asymptotic closed-form expressions for the ESSR of the downlink NOMA system, and show that the performance can be classified into two distinct regimes, i.e., it is dictated either by the interference constraint or by the power constraint. Our results confirm the superiority of the NOMA-based system over its orthogonal multiple access (OMA) based counterpart. More interestingly, our results show that NOMA helps in maintaining the secrecy rate of the strong user while significantly enhancing the secrecy performance of the weak user as compared to OMA. The correctness of the proposed investigation is corroborated through Monte Carlo simulation.</div>

On the Secrecy Rate of Downlink NOMA in Underlay Spectrum Sharing with Imperfect CSI: Invited Paper

2021 ◽  
Author(s):  
Vaibhav Kumar ◽  
Mark F. Flanagan ◽  
Daniel Benevides Da Costa ◽  
Le-Nam Tran
Keyword(s):  
Spectrum Sharing ◽  
Imperfect Csi ◽  
Secrecy Rate ◽  
Underlay Spectrum Sharing

Uplink Power-Domain Non-Orthogonal Multiple Access (NOMA)

2020 ◽  
Vol 12 (4) ◽  
pp. 65-73
Author(s):  
Faeik T. Al Rabee ◽  
Richard D. Gitlin
Keyword(s):  
Channel Estimation ◽  
Interference Cancellation ◽  
Multiple Access ◽  
Signal To Noise Ratio ◽  
Estimation Error ◽  
Channel Estimation Error ◽  
Estimation Errors ◽  
Channel Estimation Errors ◽  
Fifth Generation ◽  
Power Domain

Non-orthogonal multiple access (NOMA) has been proposed as a promising multiple access (MA) technique in order to meet the requirements for fifth generation (5G) communications and to enhance the performance in internet of things (IoT) networks by enabling massive connectivity, high throughput, and low latency. This paper investigates the bit error rate (BER) performance of two-user uplink power-domain NOMA with a successive interference cancellation (SIC) receiver and taking into account channel estimation errors. The analysis considers two scenarios: perfect (ideal) channel estimation and a channel with estimation errors for various modulations schemes, BPSK, QPSK, and 16-QAM. The simulation results show that, as expected, increasing of the modulation level increases the SIC receiver BER. For example, at a signal-to-noise ratio (SNR) of 5 dB for perfect channel estimation and QPSK modulation, the user that is detected first has a BER of 0.005 compared to 0.14 for the user that is detected with the aid of the SIC receiver. Similarly, the BER of QPSK, assuming 0.25 channel estimation error of user 1, is equal to 0.06 at SNR = 15 dB compared to 0.017 for perfect estimation.

scholarly journals ENERGY-EFFICIENT POWER ALLOCATION FOR IMPERFECT CSI DOWNLINK NOMA SYSTEM

2021 ◽  
Vol 11 (2) ◽  
pp. 118-129
Author(s):  
Reem Aldebes ◽  
Kaharudin Dimyati ◽  
Effariza Hanafi
Keyword(s):  
Energy Efficiency ◽  
Channel Estimation ◽  
Outage Probability ◽  
Power Allocation ◽  
Multiple Access ◽  
Estimation Error ◽  
Base Station ◽  
Channel Estimation Error ◽  
Imperfect Csi ◽  
Fifth Generation

The fifth generation (5G) networks must provide the massively increased number of users by thousand times higher data rate at lower power consumption. Thus, optimizing the energy efficiency (EE) becomes an essential issue that has to be researched from the green communication perspective. Non-orthogonal multiple access (NOMA) is considered one of the high potential techniques in fifth-generation systems. This technology is favorable to maximize the energy efficiency and the spectrum efficiency by composing different signals at the same time on the same carrier at different power levels. In this paper, a low complexity power allocation algorithm is proposed in imperfect channel state information (CSI) downlink NOMA cellular system, where obtaining full CSI at the base station is considered a challenge. The proposed algorithm relies on the fact that the allocated power is inversely proportional to the channel strength of the user to implement the successive interference cancellation (SIC) technique at the user terminal to reconstruct the desired signal. The performance of the system is analyzed in terms of energy efficiency and outage probability and compared to the conventional orthogonal multiple access (OMA) system. Results show that the proposed algorithm increases the energy efficiency by about 50% compared to the conventional OMA technology, and an improvement in the outage probability has been achieved. Furthermore, the effect of the error in the channel estimation on the energy efficiency in imperfect CSI NOMA system is evaluated. The simulation shows that the energy efficiency reduces when the channel estimation error increases; and the best performance is achieved in the perfect CSI case where the channel estimation error is zero.

Channel capacity analysis of non-orthogonal multiple access and massive multiple-input multiple-output wireless communication networks considering perfect and imperfect channel state information

2021 ◽  
pp. 154851292110001
Author(s):  
Ravi Shankar ◽  
Shovon Nandi ◽  
Ajay Rupani
Keyword(s):  
Multiple Access ◽  
Mimo System ◽  
Estimation Error ◽  
Multiple Input Multiple Output ◽  
Channel Estimation Error ◽  
Channel State ◽  
State Information ◽  
Multiple User ◽  
Multiple Input ◽  
Input Multiple Output

In this paper, we investigate the non-orthogonal multiple access (NOMA) and massive multiple-input multiple-output (M-MIMO) techniques and through simulation, and a comparison is given between the NOMA and orthogonal multiple access techniques. Integrating NOMA with M-MIMO is a very challenging task. In this paper, for a single-cell system, NOMA is integrated with a M-MIMO system for better spectral and energy efficiency. Investigation of the multiple user gain is the focus of this work because the multiple user gain supports simultaneous transmission of multiple users in the case of the M-MIMO system. In this way, the M-MIMO will provide a 100 times channel capacity increase, which results in very high data transmission rate. In the modern communication system, achieving multiple user gain is a very difficult task when channel estimation error is present. The performance of the orthogonal multiple access as well as NOMA system significantly reduced in the presence of channel estimation error. However, most of the current schemes do not work well with imperfect perfect channel state information conditions. Simulation results closely agree with the theoretical outcomes.

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