scholarly journals Spectral efficiency analysis of two-user Downlink PD-NOMA with LTE modulation and coding schemes

2021 ◽  
Vol 2134 (1) ◽  
pp. 012023
Author(s):  
Ya. V. Kryukov ◽  
D. A. Pokamestov ◽  
R. R. Abenov ◽  
S. M. Mukhamadiev ◽  
I. Kanatbekuli
Keyword(s):  
Spectral Efficiency ◽  
Multiple Access ◽  
High Efficiency ◽  
Signal To Noise Ratio ◽  
Time Frequency ◽  
Coding Schemes ◽  
Power Domain ◽  
Real Performance ◽  
Practical Performance

Abstract Non-orthogonal multiple access (NOMA) is a promising user multiplexing technique for future wireless networks that allows increasing their spectral efficiency (SE). Power-Domain NOMA (PD-NOMA) is one of the most perspective techniques in the NOMA group. It makes it possible to perform the transmission of information symbols of several users within the same time-frequency resource segment (RS) without a spreading code. Many research works show the high efficiency of PD-NOMA compared to the orthogonal multiple access (OMA). However, these results are obtained analytically using Shannon’s formula and not taking into account the real performance of existing modulation and coding schemes (MCS). The issue is that it is impossible to obtain the achievable practical performance of PD-NOMA systems in this way. We obtain the SE in RS of a PD-NOMA system with Long Term Evolution (LTE) MCS’s and compare it with OMA. As a result, we conclude that PD-NOMA gains the system SE when the multiplexed user’s signal-to-noise ratio (SNR) outreaches the threshold of the highest performing MCS provided for the transmission by a MCS table.

scholarly journals Uplink Transmit Power Control for Single-Carrier Grouped FDMA with Iterative Multiuser Detection

2019 ◽  
Vol 10 (1) ◽  
pp. 119
Author(s):  
Yong-Sang Cho ◽  
Yun-Seong Kang ◽  
Moonsik Min
Keyword(s):  
Power Control ◽  
Multiuser Detection ◽  
Spectral Efficiency ◽  
Control Method ◽  
Signal To Noise Ratio ◽  
Transmit Power ◽  
Time Frequency ◽  
Evolution Simulation ◽  
Single Carrier ◽  
Iterative Multiuser Detection

We consider an uplink power allocation scheme for single-carrier frequency-division multiple access (FDMA) with iterative multiuser detection, called single-carrier grouped FDMA (SC-GFDMA). SC-GFDMA is a non-orthogonal scheme in which several users share a single time-frequency resource. Hence, the uplink signal of a user can be regarded as both a signal and a source of interference. The signal power of each user should be sufficiently high to ensure reliable signal detection and sufficiently low to suppress inter-user interference. That is, the transmit power of each user should be adjusted appropriately to achieve high spectral efficiency. In this context, a power control method for an uplink SC-GFDMA system is proposed by analyzing the signal-to-interference-plus-noise ratios of users sharing each time-frequency resource. In particular, the uplink spectral efficiency is improved by limiting the transmit power of each user according to a criterion derived using a semi-analytic method called signal-to-noise ratio-variance density evolution. Simulation results demonstrate that the proposed method can significantly increase the spectral efficiency of the system, even with a considerably reduced total transmit power.

Sum rate capacity of non-orthogonal multiple access scheme with optimal power allocation

2021 ◽  
pp. 154851292098353
Author(s):  
Lokesh Bhardwaj ◽  
Ritesh Kumar Mishra ◽  
Ravi Shankar
Keyword(s):  
Power Allocation ◽  
Multiple Access ◽  
Signal To Noise Ratio ◽  
Optimal Power Allocation ◽  
Cumulative Density Function ◽  
Optimal Power ◽  
Power Domain ◽  
Access Scheme ◽  
Rate Capacity ◽  
Sum Rate

In this work, the performance of the downlink non-orthogonal multiple access (NOMA) technique is investigated for two users considering optimal power allocation factors. The power domain NOMA differentiates the users based on channel gains by providing different power levels and it is demonstrated that optimal power allocation is only possible when the gain ratio is maximum. Further, the range of optimal power levels is derived for the strong user having better channel conditions. Furthermore, the outage probability (OP) has been derived for ordered NOMA in the downlink through the cumulative density function-based approach. The simulation results demonstrate the improvement in sum rate capacity for optimal power allocation as compared to random power allocation, and the OP reduces with the signal-to-noise ratio more sharply for the stronger user.

scholarly journals First-Arrival Picking for Microseismic Monitoring Based on Deep Learning

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Xiaolong Guo
Keyword(s):  
Deep Learning ◽  
High Efficiency ◽  
Signal To Noise Ratio ◽  
Microseismic Monitoring ◽  
Signal To Noise ◽  
Short Term ◽  
Real Time Processing ◽  
Monitoring Process ◽  
First Arrival

In microseismic monitoring, achieving an accurate and efficient first-arrival picking is crucial for improving the accuracy and efficiency of microseismic time-difference source location. In the era of big data, the traditional first-arrival picking method cannot meet the real-time processing requirements of microseismic monitoring process. Using the advanced idea of deep learning-based end-to-end classification and the prominent feature extraction advantages of a fully convolution neural network, this paper proposes a first-arrival picking method of effective signals for microseismic monitoring based on UNet++ network, which can significantly improve the accuracy and efficiency of first-arrival picking. In this paper, we first introduced the methodology of the UNet++-based picking method. And then, the performance of the proposed method is verified by the experiments with finite-difference forward modeling simulated signals and actual microseismic records under different signal-to-noise ratios, and finally, comparative experiments are performed using the U-Net-based first-arrival picking algorithm and the Short-Term Average to Long-Term Average (STA/LTA) algorithm. The results show that compared to the U-Net network, the proposed method can obviously improve the first-arrival picking accuracy of the low signal-to-noise ratio microseismic signals, achieving significantly higher accuracy and efficiency than the STA/LTA algorithm, which is famous for its high efficiency in traditional algorithms.

scholarly journals Evaluation of 5G Key Technique: Non-Orthogonal Multiple Access

2019 ◽  
Vol 8 (2S8) ◽  
pp. 1314-1316
Keyword(s):  
Power Allocation ◽  
Spectral Efficiency ◽  
Interference Cancellation ◽  
Multiple Access ◽  
Quality Data ◽  
Data Service ◽  
Front Edge ◽  
Power Domain ◽  
Channel Interference ◽  
Code Domain

Non-orthogonal multiple access has been put forward as a key technique for 5G. It can provide power-domain and code-domain multiplexing and enables to satisfy the data demand. Its capacity and spectral efficiency are investigated-ed and analyzed. In comparison to the conventional orthogonal multiple access, the existing dominant non-orthogonal multiple access can provide a higher quality data service for multiple users when the transmitted signals are empowered by the power allocation technique and the received signals are decoded by the channel interference cancellation scheme. In this study, NOMA is found to be a front-edge technology the 5G communications.

scholarly journals Link and System-Level NOMA Simulator: The Reproducibility of Research

Electronics ◽  
2021 ◽  
Vol 10 (19) ◽  
pp. 2388
Author(s):  
Arsla Khan ◽  
Muhammad Arslan Usman ◽  
Muhammad Rehan Usman ◽  
Muneeb Ahmad ◽  
Soo-Young Shin
Keyword(s):  
Spectral Efficiency ◽  
Channel Coding ◽  
Multiple Access ◽  
Performance Metrics ◽  
Fold Increase ◽  
System Level ◽  
Intercell Interference ◽  
The Many ◽  
Level Analysis

This study focuses on the design of a MATLAB platform for non-orthogonal multiple access (NOMA) based systems with link-level and system-level analyses. Among the different potential candidates for 5G, NOMA is gaining considerable attention owing to the many-fold increase in spectral efficiency as compared to orthogonal multiple access (OMA). In this study, a NOMA simulator is presented for two and more than two users in a single cell for link-level analysis; whereas, for system-level analysis, seven cells and 19 cells scenarios were considered. Long-term evolution (LTE) was used as the baseline for the NOMA simulator, while bit error rate (BER), throughput and spectral efficiency are used as performance metrics to analyze the simulator performance. Moreover, we demonstrated the application of the NOMA simulator for different simulation scenarios through examples. In addition, the performance of multi-carrier NOMA (MC-NOMA) was evaluated in the presence of AWGN, impulse noise, and intercell interference. To circumvent channel impairments, channel coding with linear precoding is suggested to improve the BER performance of the system.

scholarly journals Uplink IoT Networks: Time-Division Priority-Based Non-Orthogonal Multiple Access Approach

2021 ◽  
Author(s):  
Basem M. Elhalawany ◽  
Ahmad A.Aziz El-Banna ◽  
Kaishun Wu ◽  
Wali Ullah Khan
Keyword(s):  
Power Allocation ◽  
Spectral Efficiency ◽  
Interference Cancellation ◽  
Multiple Access ◽  
Signal To Noise Ratio ◽  
Ergodic Capacity ◽  
Transmission Time ◽  
Limited Power ◽  
Iot Devices ◽  
Time Division

Non-orthogonal multiple access (NOMA) has been investigated to support massive connectivity for Internet-of-things (IoT) networks. However, since most IoT devices suffer from limited power and decoding capabilities, it is not desirable to pair a large number of devices simultaneously, which encourages two-user NOMA grouping. Additionally, most existing techniques have not considered the diversity in the target QoS of IoT devices, which may lead to spectrum inefficiency. Few investigations have partially considered that issue by using an order-based power allocation (OPA) approach, where the power is allocated according to the order to the user's target throughput within a priority-based NOMA (PNOMA) group. However, this does not fully capture the effects of diversity in the values of the users' target throughputs. In this work, we handle both problems by considering a throughput-based power allocation (TPA) approach, that captures the QoS diversity, within a three-users PNOMA group as a compromise between spectral efficiency and complexity. Specifically, we investigate the performance of a time-division PNOMA (TD-PNOMA) scheme, where the transmission time is divided into two-time slots with two-users per PNOMA group. The performance of such TD-PNOMA is compared with a fully PNOMA (F-PNOMA) scheme, where the three users share the whole transmission time, in terms of the ergodic capacity under imperfect successive interference cancellation (SIC). The results reveal the superiority of TPA compared with OPA approach in both schemes, besides that the throughput of both schemes can outperform each other under imperfect SIC based on the transmit signal-to-noise ratio and the deployment scenarios.

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 Enabling Non-Linear Energy Harvesting in Power Domain Based Multiple Access in Relaying Networks: Outage and Ergodic Capacity Performance Analysis

Electronics ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 817 ◽  
Author(s):  
Thanh-Luan Nguyen ◽  
Minh-Sang Van Nguyen ◽  
Dinh-Thuan Do ◽  
Miroslav Voznak
Keyword(s):  
Energy Harvesting ◽  
Outage Probability ◽  
Multiple Access ◽  
Signal To Noise Ratio ◽  
Ergodic Capacity ◽  
Green Communications ◽  
Access Policy ◽  
Power Domain ◽  
Proposed Model ◽  
Non Linear

The Power Domain-based Multiple Access (PDMA) scheme is considered as one kind of Non-Orthogonal Multiple Access (NOMA) in green communications and can support energy-limited devices by employing wireless power transfer. Such a technique is known as a lifetime-expanding solution for operations in future access policy, especially in the deployment of power-constrained relays for a three-node dual-hop system. In particular, PDMA and energy harvesting are considered as two communication concepts, which are jointly investigated in this paper. However, the dual-hop relaying network system is a popular model assuming an ideal linear energy harvesting circuit, as in recent works, while the practical system situation motivates us to concentrate on another protocol, namely non-linear energy harvesting. As important results, a closed-form formula of outage probability and ergodic capacity is studied under a practical non-linear energy harvesting model. To explore the optimal system performance in terms of outage probability and ergodic capacity, several main parameters including the energy harvesting coefficients, position allocation of each node, power allocation factors, and transmit signal-to-noise ratio (SNR) are jointly considered. To provide insights into the performance, the approximate expressions for the ergodic capacity are given. By matching analytical and Monte Carlo simulations, the correctness of this framework can be examined. With the observation of the simulation results, the figures also show that the performance of energy harvesting-aware PDMA systems under the proposed model can satisfy the requirements in real PDMA applications.

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