scholarly journals Employing non-orthogonal multiple access scheme in UAV-based wireless networks

2021 ◽  
Vol 10 (1) ◽  
pp. 241-248
Author(s):  
Chi- Bao Le ◽  
Dinh- Thuan Do
Keyword(s):  
Multiple Access ◽  
Large Scale ◽  
Signal To Noise Ratio ◽  
Base Station ◽  
Spectrum Efficiency ◽  
Allocation Scheme ◽  
Access Scheme ◽  
Aerial Vehicle ◽  
Fixed Power ◽  
The Internet Of Things

This paper studies the two-hop transmission relying unmanned aerial vehicle (UAV) relays which is suitable to implement in the internet of things (IoT) systems. To enhance system performance in order to overcome the large scale fading between the base station (BS) and destination as well as achieve the higher spectrum efficiency, where non-orthogonal multiple access (NOMA) strategies were typically applied for UAV relays to implement massive connections transmission. In particular, outage probability is evaluated via signal to noise ratio (SNR) criterion so that the terminal node can obtain reasonable performance. The derivations and analysis results showed that the considered fixed power allocation scheme provides performance gap among two signals at destination.The numerical simulation confirmed the exactness of derived expressions in the UAV assisted system.

scholarly journals Secure outage probability of cognitive radio network relying non-orthogonal multiple access scheme

2021 ◽  
Vol 10 (2) ◽  
pp. 828-836
Author(s):  
Chi-Bao Le ◽  
Dinh-Thuan Do
Keyword(s):  
Outage Probability ◽  
Multiple Access ◽  
Cognitive Radio Network ◽  
Signal To Noise Ratio ◽  
Base Station ◽  
Secondary Source ◽  
Radio Network ◽  
Secondary Network ◽  
Access Scheme ◽  
The Internet Of Things

This paper studies the secondary network relying relay selection to transmit signal from the secondary source (base station) to two destinations. Especially, two destinations are required non-orthogonal multiple access (NOMA) scheme and it benefits to implementation of the Internet of Things (IoT) systems. However, eavesdropper over-hears signal related link from selected relay to destination. This paper measure secure performance via metric, namely secure outage probability (SOP). In particular, signal to noise ratio (SNR) criterion is used to evalute SOP to provide reliable transmission to the terminal node. Main results indicates that the considered scheme provides performance gap among two signals at destination. The exactness of derived expressions is confirmed via numerical simulation.

scholarly journals NOMA-Assisted Multiple Access Scheme for IoT Deployment: Relay Selection Model and Secrecy Performance Improvement

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 736 ◽  
Author(s):  
Dinh-Thuan Do ◽  
Minh-Sang Van Nguyen ◽  
Thi-Anh Hoang ◽  
Miroslav Voznak
Keyword(s):  
Performance Improvement ◽  
Relay Selection ◽  
Multiple Access ◽  
Signal To Noise Ratio ◽  
Base Station ◽  
Master Node ◽  
Access Scheme ◽  
Setting Parameters ◽  
Different Levels ◽  
Relaying System

In this paper, an Internet-of-Things (IoT) system containing a relay selection is studied as employing an emerging multiple access scheme, namely non-orthogonal multiple access (NOMA). This paper proposes a new scheme to consider secure performance, to be called relay selection NOMA (RS-NOMA). In particular, we consider metrics to evaluate secure performance in such an RS-NOMA system where a base station (master node in IoT) sends confidential messages to two main sensors (so-called NOMA users) under the influence of an external eavesdropper. In the proposed IoT scheme, both two NOMA sensors and an illegal sensor are served with different levels of allocated power at the base station. It is noticed that such RS-NOMA operates in two hop transmission of the relaying system. We formulate the closed-form expressions of secure outage probability (SOP) and the strictly positive secure capacity (SPSC) to examine the secrecy performance under controlling setting parameters such as transmit signal-to-noise ratio (SNR), the number of selected relays, channel gains, and threshold rates. The different performance is illustrated as performing comparisons between NOMA and orthogonal multiple access (OMA). Finally, the advantage of NOMA in secure performance over orthogonal multiple access (OMA) is confirmed both analytically and numerically.

scholarly journals Effective Capacity Analysis of Reconfigurable Intelligent Surfaces Aided NOMA Network

2021 ◽  
Author(s):  
Geng Li ◽  
Huiling Liu ◽  
Gaojian Huang ◽  
Xingwang Li ◽  
Bichu Raj ◽  
...  
Keyword(s):  
Multiple Access ◽  
Signal To Noise Ratio ◽  
Analytical Approximation ◽  
Base Station ◽  
Effective Capacity ◽  
Green Communication ◽  
Time Service ◽  
Delay Sensitive ◽  
Sixth Generation ◽  
Evaluation Metric

Abstract The future sixth generation (6G) is going to face the significant challenges of massive connections and green communication. Recently, reconfigurable intelligent surfaces (RIS) and non-orthogonal multiple access (NOMA) have been proposed as two key technologies to address the above problems. Motivated by this fact, we consider a downlink RIS-aided NOMA system, where the base station seeks to communicate with two NOMA users with the aid of a RIS. Considering future network supporting real-time service, we investigate the system performance with the view of effective capacity (EC), which is an important evaluation metric of sensitive to delay sensitive system. Based on this basis, we derive the analytical expressions of the EC of the near and far users. To obtain more useful insights, we deduce the analytical approximation expressions of the EC in the low signal-to-noise-ratio (SNR) approximation by utilizing Taylor expansion. In order to compare, we provide the results of orthogonal multiple access (OMA). It is found that 1) The number of RIS components and the transmission power of the base station have important effects on the performance of the considered system model. 2) Compared with OMA, NOMA system has higher effective capacity due to the short transmission time.

Resource Allocation in Orthogonal Frequency Division Multiple Access-Long Term Evaluation: Neural Network

2019 ◽  
Vol 16 (12) ◽  
pp. 5026-5031
Author(s):  
Kethavath Narender ◽  
C. Puttamadappa
Keyword(s):  
Neural Network ◽  
Resource Allocation ◽  
Communication Systems ◽  
Multiple Access ◽  
Large Scale ◽  
Cuckoo Search ◽  
Base Station ◽  
Frequency Division ◽  
Term Evaluation

Symmetrical Frequency Division Multiple Access (OFDMA) is utilized in the higher rate Wireless Communication Systems (WCSs). In the correspondence framework, a fem to cell is a little cell in building Base Station (BS), which devours less power, short range, and works in a minimal effort. The fem to cell has little separation among sender and recipient that give higher flag quality. In spite of the favorable position in fem to cell systems, there win critical difficulties in Interference Management. Specifically, impedance between the macro cell and fem to cell turns into the fundamental issue in OFDMA-Long Term Evaluation (OFDMA-LTE) framework. In this paper, the Neural Network and Hybrid Bee Colony and Cuckoo Search based Resource Allocation (NN-HBCCS-RA) in OFDMA-LTE framework is presented. The ideal power esteems are refreshed to dispense every one of the clients in the fem to cell and large scale cell. The NN-HBCCS strategy accomplished low Signal to Interference Noise Ratio (SINR), otherworldly proficiency and high throughput contrasted with customary techniques.

Performance of Multi-User Transmitter Pre-Processing Assisted Multi-Cell IDMA System for Downlink Transmission

2015 ◽  
Vol 14 (03) ◽  
pp. 1550030 ◽  
Author(s):  
B. Partibane ◽  
V. Nagarajan ◽  
K. S. Vishvaksenan ◽  
R. Kalidoss
Keyword(s):  
Multiple Access ◽  
Signal To Noise Ratio ◽  
Minimum Mean Square Error ◽  
Multiple Access Interference ◽  
Base Station ◽  
Least Square ◽  
Complex Signal ◽  
Delay Spread ◽  
Downlink Transmission ◽  
Mmse Detector

In this paper, we present the performance of multi-user transmitter pre-processing (MUTP) assisted coded-interleave division multiple access (IDMA) system over correlated frequency-selective channels for downlink communication. We realize MUTP using singular value decomposition (SVD) technique, which exploits the channel state information (CSI) of all the active users that is acquired via feedback channels. We consider the MUTP technique to alleviate the effects of co-channel interference (CCI) and multiple access interference (MAI). To be specific, we estimate the CSI using least square error (LSE) algorithm at each of the mobile stations (MSs) and perform vector quantization using Lloyd's algorithm, and feedback the bits that represents the quantized magnitudes and phases to the base station (BS) through the dedicated low rate noisy channel. Finally we recover the quantized bits at the BS to formulate the pre-processing matrix. The performance of MUTP aided IDMA systems are evaluated for five types of delay spread distributions pertaining to long-term evolution (LTE) and Stanford University Interim (SUI) channel models. We also compare the performance of MUTP with minimum mean square error (MMSE) detector for the coded IDMA system. The considered TP scheme alleviates the effects of CCI with less complex signal detection at the MSs when compared to MMSE detector. Further, our simulation results reveal that SVD-based MUTP assisted coded IDMA system outperforms the MMSE detector in terms of achievable bit error rate (BER) with low signal-to-noise ratio (SNR) requirement by mitigating the effects of CCI and MAI.

scholarly journals On the Performance Balancing for Uplink NOMA Systems

2020 ◽  
Vol 13 (6) ◽  
pp. 454-459
Author(s):  
Nam-Soo Kim ◽  
Keyword(s):  
Outage Probability ◽  
Multiple Access ◽  
Signal To Noise Ratio ◽  
Ergodic Capacity ◽  
Base Station ◽  
Cellular Systems ◽  
Mobile Cellular ◽  
Noise Ratio ◽  
Outage Probabilities ◽  
Error Floors

Outage probability and capacity are the representative performance measures for the quality of service (QoS) in mobile cellular systems. Recently, power back-off scheme is proposed in uplink non-orthogonal multiple access (NOMA) systems. The power back-off scheme improves the performance of a near user, however, decreases that of a far user. In comparison, the scheme indicates the error floors with an outage probability of 2.4×〖10〗^(-1) and 9.1×〖10〗^(-2) with power back-off 5 dB and 10 dB, respectively under the specified condition. To address these drawbacks, we propose an equal average signal-to–interference plus noise ratio (SINR) scheme that derives the same average SINR from active users at the base station (BS) in uplink non-orthogonal multiple access (NOMA) systems. Numerical results show that required signal-to-noise ratio (SNR) for the outage probability of 1×〖10〗^(-3) of the near and far users are close enough within 1 dB, which means an outage balance between two users. And it is noticed that the outage probabilities in the proposed scheme decrease as the increase of the received SNR without error floors. Also, different from the power back-off scheme, we noticed that the capacities of the two users in the proposed scheme are coincident and increase with SNR. The outage probabilities and ergodic capacity of the near and far users are derived in closed-form expressions. The analytical results are conformed by Monte Carlo simulation.

scholarly journals On Throughput for UAV Relay Assisted for Use in Disaster Communications

2021 ◽  
Author(s):  
Van Vo Nhan ◽  
Dang Ngoc Cuong ◽  
Tran Ban Thach ◽  
Hung Tran
Keyword(s):  
System Performance ◽  
Multiple Access ◽  
Base Station ◽  
Closed Form Expression ◽  
Second Phase ◽  
Form Expression ◽  
Decode And Forward ◽  
Disaster Communications ◽  
Aerial Vehicle ◽  
Two Phases

In this paper, the system performance of an energy harvesting (EH) unmanned aerial vehicle (UAV) system for use in disasters was investigated. The communication protocol was divided into two phases. In the first phase, a UAV relay (UR) harvested energy from a power beacon (PB). In the second phase, a base station (BS) transmitted the signal to the UR using non-orthogonal multiple access (NOMA); then, the UR used its harvested energy from the first phase to transfer the signal to two sensor clusters, i.e., low-priority and high-priority clusters, via the decode-and-forward (DF) technique. A closed-form expression for the throughput of the cluster heads of these clusters was derived to analyze the system performance. Monte Carlo simulations were employed to verify our approach.

scholarly journals Time Switching Based Wireless Powered Relay Transmission with Uplink NOMA

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5467
Author(s):  
Zhihua Lin ◽  
Shihua Cao ◽  
Jianqing Li
Keyword(s):  
Multiple Access ◽  
Relay Node ◽  
Base Station ◽  
Spectrum Efficiency ◽  
Transmission Model ◽  
System Throughput ◽  
Time Switching ◽  
Power Domain ◽  
End Node ◽  
Save Energy

Non-orthogonal multiple access (NOMA) utilizes power domain multiplexing to improve spectrum efficiency compared with orthogonal multiple access (OMA). In the Internet of Things (IoT) uplink NOMA networks, if the channel between the far-end node and the base station is in deep fading, allocating larger transmitting power for this node cannot achieve higher spectrum efficiency and overall system throughput. Relay cooperative communication reduces the transmitting power at the far-end node but leads to extra energy expenditure at the relay node. Fortunately, simultaneous wireless information and power transfer (SWIPT) is advocated in energy-constrained IoT networks to save energy consumption. However, early works all focus on energy harvesting (EH) from one source node or one dedicated power supply station. In this paper, we propose a time switching based wireless powered relay transmission model with uplink NOMA where our EH technique can harvest energy from two simultaneously transmitting nodes. More importantly, by optimizing relay position more energy is harvested from the near-end node at the relay and relay signal attenuation to the destination is reduced as well. Furthermore, the closed-form expressions of outage probability and overall system throughput are derived, and numerical results prove that NOMA in our EH scheme achieves better performance compared to the traditional EH scheme and OMA by optimizing the position of the relay node, time switching factor and so on.

scholarly journals Gyre Precoding and T-Transformation-Based GFDM System for UAV-Aided mMTC Network

Electronics ◽  
2021 ◽  
Vol 10 (23) ◽  
pp. 2915
Author(s):  
Joarder Jafor Sadique ◽  
Shaikh Enayet Ullah ◽  
Raad Raad ◽  
Md. Rabiul Islam ◽  
Md. Mahbubar Rahman ◽  
...  
Keyword(s):  
Channel Coding ◽  
Signal To Noise Ratio ◽  
Multiple Input Multiple Output ◽  
Mobility Model ◽  
Base Station ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Aerial Vehicle ◽  
Noise Ratio ◽  
User Interference

In this paper, an unmanned aerial vehicle (UAV)-aided multi-antenna configured downlink mmWave cooperative generalized frequency division multiplexing (GFDM) system is proposed. To provide physical layer security (PLS), a 3D controlled Lorenz mapping system is introduced. Furthermore, the combination of T-transformation spreading codes, walsh Hadamard transform, and discrete Fourier transform (DFT) techniques are integrated with a novel linear multi-user multiple-input multiple-output (MU-MIMO) gyre precoding (GP) for multi-user interference reduction. Furthermore, concatenated channel-coding with multi-user beamforming weighting-aided maximum-likelihood and zero forcing (ZF) signal detection schemes for an improved bit error rate (BER) are also used. The system is then simulated with a single base station (BS), eight massive machine-type communications (mMTC) users, and two UAV relay stations (RSs). Numerical results reveal the robustness of the proposed system in terms of PLS and an achievable ergodic rate with signal-to-interference-plus-noise ratio (SINR) under the implementation of T-transformation scheme. By incorporating the 3D mobility model, brownian perturbations of the UAVs are also analyzed. An out-of-band (OOB) reduction of 320 dB with an improved BER of 1×10−4 in 16-QAM for a signal-to-noise ratio, Eb/N0, of 20 dB is achieved.

scholarly journals Benefiting wireless power transfer scheme in power domain based multiple access: ergodic rate performance evaluation

2021 ◽  
Vol 10 (2) ◽  
pp. 785-792
Author(s):  
Anh-Tu Le ◽  
Minh-Sang Van Nguyen ◽  
Dinh-Thuan Do
Keyword(s):  
Power Allocation ◽  
Multiple Access ◽  
Wireless Power Transfer ◽  
Ergodic Capacity ◽  
Base Station ◽  
Power Transfer ◽  
Wireless Power ◽  
Transfer Scheme ◽  
Power Domain ◽  
Fixed Power

Power domain based multiple access scheme is introduced in this paper, namely Non-orthogonal multiple-access (NOMA). We deploy a wireless network using NOMA together with a wireless power transfer (WPT) scheme for dedicated user over Nakagami-$m$ fading channel. When combined, these promising techniques (NOMA and WPT) improve the system performance in term of ergodic performance at reasonable coefficient of harvested power. However, fixed power allocation factors for each NOMA user can be adjusted at the base station and it further provide performance improvement. We design a new signal frame to deploy a NOMA scheme in WPT which adopts a linear energy harvesting model. The ergodic capacity in such a NOMA network and power allocation factors can be updated frequently in order to achieve a fair distribution among NOMA users. The exact expressions of ergodic capacity for each user is derived. The simulation results show that an agreement between analytic performance and Monte-Carlo simulation can be achieved. 

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