scholarly journals A Novel Cooperative Network Using Down-link Non-orthogonal Multiple Access Scheme

2021 ◽  
Author(s):  
Syed Agha Hassnain Mohsan ◽  
Moqbel Ali Mohammed Hamood ◽  
Syed Muhammad Tayyab Shah ◽  
Alireza Mazinani
Keyword(s):  
Spectral Efficiency ◽  
Multiple Access ◽  
Main Idea ◽  
Base Station ◽  
Cooperative Transmission ◽  
Diversity Order ◽  
Efficiency Gain ◽  
Cooperative Network ◽  
Access Scheme ◽  
Better Than

Abstract A novel downlink cooperative non-orthogonal multiple access (DC-NOMA) scheme is proposed in this paper to achieve higher performance in the spectral efficiency compared to the classical NOMA schemes. The communication system consists of one base station and two users (e.g., strong user and weak user). In down link phase, the base station transmits a superimposed signal to both users, and in the cooperative phase, the weak user sends its decoded message to the strong user. The main idea is how the weak user can help the strong user to improve the performance of both users. This occurs by enabling the weak user to perform a cooperative transmission with the strong user during the cooperative phase. The outage probability, outage throughput, and diversity order are derived and analyzed. Numerical results are provided to show that the spectral efficiency gain achieved through our proposed scheme is better than the conventional cooperative NOMA schemes.

Next Generation Wireless Multiple Access Technology OFDMA and SC - FDMA Performance Analysis

2013 ◽  
Vol 336-338 ◽  
pp. 1670-1675
Author(s):  
Lin Wan
Keyword(s):  
Multiple Access ◽  
System Capacity ◽  
Frequency Division ◽  
Theoretical Derivation ◽  
Access Technology ◽  
Single Carrier ◽  
Access Scheme ◽  
Basic Performance ◽  
Better Than

orthogonal frequency division multiple access (OFDMA) and single carrier frequency division multiple access (SC - FDMA) are the two kinds of 4 g wireless multiple access scheme. In the long term evolution (LTE) downlink link access scheme based on OFDMA, at the same time, the uplink access scheme based on SC - FDMA. In this article, we deduced the OFDMA and SC - FDMA basic performance difference, and then demonstrates the comprehensive performance comparisons between them. Theoretical derivation results show that the system capacity is better than that of SC - FDMA OFDMA. Then, we use the numerical simulation results confirm the conclusion. Keywords: OFDMA SC - FDMA basic capacity of the uplink transmission

Examination of a non-orthogonal multiple access scheme for next generation wireless networks

2020 ◽  
pp. 154851292095127
Author(s):  
Ravi Shankar
Keyword(s):  
Multiple Access ◽  
High Performance ◽  
High Reliability ◽  
Wireless Systems ◽  
Bandwidth Efficiency ◽  
Fifth Generation ◽  
Access Scheme ◽  
Simulation Results ◽  
The Relationship ◽  
Better Than

Non-orthogonal multiple access (NOMA) is an important technique that enables fifth-generation (5G) wireless systems to satisfy the heterogeneous requirements of enhanced fairness, huge connectivity, high performance, low latency, and high reliability. In this work, the NOMA technique for 5G wireless communication is investigated, and considering user fairness limitations, the channel capacity has been optimized. Also, bandwidth efficiency (BE) is examined and the relationship between BE and energy efficiency (EE) is derived. Simulation results show that without wasting power the near user gets preference in power allocation when the target rate is greater than 6.4 bps/Hz. Also, when the target rate [Formula: see text] 6.4 bps/Hz, the outage performance of the near user will improve and the performance of the far user will remain the same. Also, it is demonstrated that cooperative NOMA outperforms all other techniques. Simulation outcomes confirm that NOMA performs better than conventional multiple access techniques in terms of EE and BE.

scholarly journals QoS-Oriented Dynamic Power Allocation in NOMA-based Wireless Caching Networks

2020 ◽  
Author(s):  
Yue Yin ◽  
Miao Liu ◽  
Guan Gui ◽  
Haris Gacanin ◽  
Fumiyuki Adachi
Keyword(s):  
Quality Of Service ◽  
Power Allocation ◽  
Spectral Efficiency ◽  
Multiple Access ◽  
Base Station ◽  
System Efficiency ◽  
Allocation Strategy ◽  
Dynamic Power ◽  
Qos Requirement

<div>Non-orthogonal multiple access (NOMA) based</div><div>wireless caching network (WCN) is considered as one of the most</div><div>promising technologies for next-generation wireless communications</div><div>since it can significantly improve the spectral efficiency.</div><div>In this paper, we propose a quality of service (QoS)-oriented</div><div>dynamic power allocation strategy for NOMA-WCN. In content</div><div>stack phase, the base station sends multiple files to the content</div><div>servers by allocating different powers according to the different</div><div>QoS targets of files, for ensuring that all content servers can</div><div>successfully decode the two most popular files. In content deliver</div><div>phase, the content servers serve two users at the same time</div><div>by allocating the minimum power to the far user according</div><div>to the QoS requirement, and then all the remaining power is</div><div>allocated to the near user. Hence, the proposed power allocation</div><div>scheme is able to increase the hit probability and drop the outage</div><div>probability compared with conventional method. Simulation</div><div>results confirm that the proposed power allocation method can</div><div>significantly improve the caching hit probability and reduce the</div><div>user outage probability. It is also shown that this strategy can</div><div>reduce the user delay time, improve the system efficiency and</div><div>the capacity.</div>

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 Joint time and power allocation for uplink cooperative non-orthogonal multiple access based massive machine-type communication Network

2018 ◽  
Vol 14 (5) ◽  
pp. 155014771877821 ◽  
Author(s):  
Shujun Han ◽  
Xiaodong Xu ◽  
Litong Zhao ◽  
Xiaofeng Tao
Keyword(s):  
Communication Network ◽  
Power Allocation ◽  
Multiple Access ◽  
Base Station ◽  
Cooperative Transmission ◽  
Allocation Algorithm ◽  
Machine Type ◽  
Communication Devices ◽  
Machine Type Communication ◽  
Transmission Phase

Non-orthogonal multiple access is an essential promising solution to support large-scale connectivity required by massive machine-type communication scenario defined in the fifth generation (5G) mobile communication system. In this article, we study the problem of energy minimization in non-orthogonal multiple access–based massive machine-type communication network. Focusing on the massive machine-type communication scenario and assisted by grouping method, we propose an uplink cooperative non-orthogonal multiple access scheme with two phases, transmission phase and cooperation phase, for one uplink cooperative transmission period. Based on uplink cooperative non-orthogonal multiple access, the machine-type communication device with better channel condition and more residual energy will be selected as a group head, which acts as a relay assisting other machine-type communication devices to communicate. In the transmission phase, machine-type communication devices transmit data to the group head. Then, the group head transmits the received data with its own data to base station in the cooperation phase. Because the massive machine-type communication devices are low-cost dominant with limited battery, based on uplink cooperative non-orthogonal multiple access, we propose a joint time and power allocation algorithm to minimize the system energy consumption. Furthermore, the proposed joint time and power allocation algorithm includes dynamic group head selection and fractional transmit time allocation algorithms. Simulation results show that the proposed solution for uplink cooperative non-orthogonal multiple access–based massive machine-type communication network outperforms other schemes.

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 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 QoS-Oriented Dynamic Power Allocation in NOMA-based Wireless Caching Networks

2020 ◽  
Author(s):  
Yue Yin ◽  
Miao Liu ◽  
Guan Gui ◽  
Haris Gacanin ◽  
Fumiyuki Adachi
Keyword(s):  
Quality Of Service ◽  
Power Allocation ◽  
Spectral Efficiency ◽  
Multiple Access ◽  
Base Station ◽  
System Efficiency ◽  
Allocation Strategy ◽  
Dynamic Power ◽  
Qos Requirement

<div>Non-orthogonal multiple access (NOMA) based</div><div>wireless caching network (WCN) is considered as one of the most</div><div>promising technologies for next-generation wireless communications</div><div>since it can significantly improve the spectral efficiency.</div><div>In this paper, we propose a quality of service (QoS)-oriented</div><div>dynamic power allocation strategy for NOMA-WCN. In content</div><div>stack phase, the base station sends multiple files to the content</div><div>servers by allocating different powers according to the different</div><div>QoS targets of files, for ensuring that all content servers can</div><div>successfully decode the two most popular files. In content deliver</div><div>phase, the content servers serve two users at the same time</div><div>by allocating the minimum power to the far user according</div><div>to the QoS requirement, and then all the remaining power is</div><div>allocated to the near user. Hence, the proposed power allocation</div><div>scheme is able to increase the hit probability and drop the outage</div><div>probability compared with conventional method. Simulation</div><div>results confirm that the proposed power allocation method can</div><div>significantly improve the caching hit probability and reduce the</div><div>user outage probability. It is also shown that this strategy can</div><div>reduce the user delay time, improve the system efficiency and</div><div>the capacity.</div>

Study of Power Control in CDMA System on the basis of optimization Technique

2017 ◽  
Vol 7 (8) ◽  
pp. 126
Author(s):  
. Geetanjli
Keyword(s):  
Power Control ◽  
Multiple Access ◽  
Optimization Technique ◽  
System Optimization ◽  
Base Station ◽  
Particle Swarm Algorithm ◽  
Cdma System ◽  
Frequency Division ◽  
Cdma Systems ◽  
Time Division

The power control in CDMA systems, grant numerous users to share resources of the system uniformly between each other, leading to expand capacity. With convenient power control, capacity of CDMA system is immense in contrast of frequency division multiple access (FDMA) and time division multiple access (TDMA). If power control is not achieved numerous problems such as the near-far effect will start to monopolize and consequently will reduce the capacity of the CDMA system. However, when the power control in CDMA systems is implemented, it allows numerous users to share resources of the system uniformly between themselves, leading to increased capacity For power control in CDMA system optimization algorithms i.e. genetic algorithm & particle swarm algorithm can be used which regulate a convenient power vector. These power vector or power levels are dogged at the base station and announce to mobile units to alter their transmitting power in accordance to these levels. The performances of the algorithms are inspected through both analysis and computer simulations, and compared with well-known algorithms from the literature.

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