scholarly journals Issues, Challenges, and Research Trends in Spectrum Management: A Comprehensive Overview and New Vision for Designing 6G Networks

Electronics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1416 ◽  
Author(s):  
Faizan Qamar ◽  
Maraj Uddin Ahmed Siddiqui ◽  
MHD Nour Hindia ◽  
Rosilah Hassan ◽  
Quang Ngoc Nguyen
Keyword(s):  
Network Architecture ◽  
Multiple Input Multiple Output ◽  
Radio Spectrum ◽  
Spectrum Management ◽  
Future Research ◽  
Comprehensive Overview ◽  
Fifth Generation ◽  
Input Multiple Output ◽  
Extensive Growth ◽  
New Vision

With an extensive growth in user demand for high throughput, large capacity, and low latency, the ongoing deployment of Fifth-Generation (5G) systems is continuously exposing the inherent limitations of the system, as compared with its original premises. Such limitations are encouraging researchers worldwide to focus on next-generation 6G wireless systems, which are expected to address the constraints. To meet the above demands, future radio network architecture should be effectively designed to utilize its maximum radio spectrum capacity. It must simultaneously utilize various new techniques and technologies, such as Carrier Aggregation (CA), Cognitive Radio (CR), and small cell-based Heterogeneous Networks (HetNet), high-spectrum access (mmWave), and Massive Multiple-Input-Multiple-Output (M-MIMO), to achieve the desired results. However, the concurrent operations of these techniques in current 5G cellular networks create several spectrum management issues; thus, a comprehensive overview of these emerging technologies is presented in detail in this study. Then, the problems involved in the concurrent operations of various technologies for the spectrum management of the current 5G network are highlighted. The study aims to provide a detailed review of cooperative communication among all the techniques and potential problems associated with the spectrum management that has been addressed with the possible solutions proposed by the latest researches. Future research challenges are also discussed to highlight the necessary steps that can help achieve the desired objectives for designing 6G wireless networks.

scholarly journals Enabling Grant-Free URLLC: An Overview of Principle and Enhancements by Massive MIMO

2021 ◽  
Author(s):  
Jie Ding ◽  
Mahyar Nemati ◽  
Shiva Pokhrel ◽  
Ok-Sun Park ◽  
Jinho Choi ◽  
...  
Keyword(s):  
Multiple Input Multiple Output ◽  
Random Access ◽  
Packet Transmission ◽  
Future Research ◽  
Data Packets ◽  
Fifth Generation ◽  
New Radio ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Radio Resources

<div>Enabling ultra-reliable low-latency communication (URLLC) with stringent requirements for transmitting data packets (e.g., 99.999% reliability and 1 millisecond latency) presents considerable challenges in uplink transmissions. For each packet transmission over dynamically allocated network radio resources, the conventional random access protocols are based on a request- rant scheme. This induces excessive latency and necessitates reliable control signalling, resulting overhead. To address these problems, grant-free (GF) solutions are proposed in the fifth-generation (5G) new radio (NR). In this paper, an overview and vision of the state-of-the-art in enabling GF URLLC are presented. In particular, we first provide a comprehensive review of NR specifications and techniques for URLLC, discuss underlying principles, and highlight impeding issues of enabling GF URLLC. Furthermore, we explain two key phenomena of massive multiple-input multiple-output (mMIMO) (i.e., channel hardening and favorable propagation) and build several deep insights into how celebrated mMIMO features can be exploited to enhance the performance of GF URLLC. Moving further ahead, we examine the potential of cell-free (CF) mMIMO and analyze its distinctive features and benefits over mMIMO to resolve GF URLLC issues. Finally, we identify future research directions and challenges in enabling GF URLLC with CF mMIMO.</div>

scholarly journals Enabling Grant-Free URLLC: An Overview of Principle and Enhancements by Massive MIMO

2021 ◽  
Author(s):  
Jie Ding ◽  
Mahyar Nemati ◽  
Shiva Pokhrel ◽  
Ok-Sun Park ◽  
Jinho Choi ◽  
...  
Keyword(s):  
Multiple Input Multiple Output ◽  
Random Access ◽  
Packet Transmission ◽  
Future Research ◽  
Data Packets ◽  
Fifth Generation ◽  
New Radio ◽  
Input Multiple Output ◽  
Radio Resources ◽  
Grant Scheme

<div>Enabling ultra-reliable low-latency communication (URLLC) with stringent requirements for transmitting data packets (e.g., 99.999% reliability and 1 millisecond latency) presents considerable challenges in uplink transmissions. For each packet transmission over dynamically allocated network radio resources, the conventional random access protocols are based on a request-grant scheme. This induces excessive latency and necessitates reliable control signalling, resulting overhead. To address these problems, grant-free (GF) solutions are proposed in the fifth-generation (5G) new radio (NR). In this paper, an overview and vision of the state-of-the-art in enabling GF URLLC are presented. In particular, we first provide a comprehensive review of NR specifications and techniques for URLLC, discuss underlying principles, and highlight impeding issues of enabling GF URLLC. Furthermore, we briefly explain two key phenomena of massive multiple-input multiple-output (mMIMO) (i.e., channel hardening and favorable propagation) and build several deep insights into how celebrated mMIMO features can be exploited to enhance the performance of GF URLLC. Moving further ahead, we examine the potential of cell-free (CF) mMIMO and analyze its distinctive features and benefits over mMIMO to resolve GF URLLC issues. Finally, we identify future research directions and challenges in enabling GF URLLC with CF mMIMO.</div><div><br></div><div><br></div><div>A new version of the paper has been updated on 21/08/2021</div>

scholarly journals Enabling Grant-Free URLLC: An Overview of Principle and Enhancements by Massive MIMO

2021 ◽  
Author(s):  
Jie Ding ◽  
Mahyar Nemati ◽  
Shiva Pokhrel ◽  
Ok-Sun Park ◽  
Jinho Choi ◽  
...  
Keyword(s):  
Multiple Input Multiple Output ◽  
Random Access ◽  
Packet Transmission ◽  
Future Research ◽  
Data Packets ◽  
Fifth Generation ◽  
New Radio ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Radio Resources

<div>Enabling ultra-reliable low-latency communication (URLLC) with stringent requirements for transmitting data packets (e.g., 99.999% reliability and 1 millisecond latency) presents considerable challenges in uplink transmissions. For each packet transmission over dynamically allocated network radio resources, the conventional random access protocols are based on a request- rant scheme. This induces excessive latency and necessitates reliable control signalling, resulting overhead. To address these problems, grant-free (GF) solutions are proposed in the fifth-generation (5G) new radio (NR). In this paper, an overview and vision of the state-of-the-art in enabling GF URLLC are presented. In particular, we first provide a comprehensive review of NR specifications and techniques for URLLC, discuss underlying principles, and highlight impeding issues of enabling GF URLLC. Furthermore, we explain two key phenomena of massive multiple-input multiple-output (mMIMO) (i.e., channel hardening and favorable propagation) and build several deep insights into how celebrated mMIMO features can be exploited to enhance the performance of GF URLLC. Moving further ahead, we examine the potential of cell-free (CF) mMIMO and analyze its distinctive features and benefits over mMIMO to resolve GF URLLC issues. Finally, we identify future research directions and challenges in enabling GF URLLC with CF mMIMO.</div>

scholarly journals Total Local Dose in Hypothetical 5G Mobile Networks for Varied Topologies and User Scenarios

2020 ◽  
Vol 10 (17) ◽  
pp. 5971 ◽  
Author(s):  
Sven Kuehn ◽  
Serge Pfeifer ◽  
Niels Kuster
Keyword(s):  
Mobile Networks ◽  
Communication Systems ◽  
Multiple Input Multiple Output ◽  
Monte Carlo Analysis ◽  
5G Networks ◽  
Fifth Generation ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Network Topologies ◽  
5G Mobile Networks

In this study, the total electromagnetic dose, i.e., the combined dose from fixed antennas and mobile devices, was estimated for a number of hypothetical network topologies for implementation in Switzerland to support the deployment of fifth generation (5G) mobile communication systems while maintaining exposure guidelines for public safety. In this study, we consider frequency range 1 (FR1) and various user scenarios. The estimated dose in hypothetical 5G networks was extrapolated from measurements in one of the Swiss 4G networks and by means of Monte Carlo analysis. The results show that the peak dose is always dominated by an individual’s mobile phone and, in the case of non-users, by the bystanders’ mobile phones. The reduction in cell size and the separation of indoor and outdoor coverage can substantially reduce the total dose by >10 dB. The introduction of higher frequencies in 5G mobile networks, e.g., 3.6 GHz, reduces the specific absorption rate (SAR) in the entire brain by an average of −8 dB, while the SAR in the superficial tissues of the brain remains locally constant, i.e., within ±3 dB. Data from real networks with multiple-input multiple-output (MIMO) were not available; the effect of adaptive beam-forming antennas on the dose will need to be quantitatively revisited when 5G networks are fully established.

Investigation of the fifth generation non-orthogonal multiple access technique for defense applications using deep learning

2021 ◽  
pp. 154851292110228
Author(s):  
Ravisankar Malladi ◽  
Manoj Kumar Beuria ◽  
Ravi Shankar ◽  
Sudhansu Sekhar Singh
Keyword(s):  
Deep Learning ◽  
Interference Cancellation ◽  
Multiple Access ◽  
Multiple Input Multiple Output ◽  
Optimal Solution ◽  
Channel State ◽  
Fifth Generation ◽  
Multiple Input ◽  
Input Multiple Output ◽  
And Performance

In modern wireless communication scenarios, non-orthogonal multiple access (NOMA) provides high throughput and spectral efficiency for fifth generation (5G) and beyond 5G systems. Traditional NOMA detectors are based on successive interference cancellation (SIC) techniques at both uplink and downlink NOMA transmissions. However, due to imperfect SIC, these detectors are not suitable for defense applications. In this paper, we investigate the 5G multiple-input multiple-output NOMA deep learning technique for defense applications and proposed a learning approach that investigates the communication system’s channel state information automatically and identifies the initial transmission sequences. With the use of the proposed deep neural network, the optimal solution is provided, and performance is much better than the traditional SIC-based NOMA detectors. Through simulations, the analytical outcomes are verified.

Oil-Spills Detection in MIMO-SAR Radar Images by High Order Statistics

2013 ◽  
Vol 443 ◽  
pp. 649-652
Author(s):  
Yan Ling Luo
Keyword(s):  
Oil Spills ◽  
Multiple Input Multiple Output ◽  
Mimo Radar ◽  
Radar Signal ◽  
Future Research ◽  
Signal Model ◽  
Radar Images ◽  
Multiple Input ◽  
Input Multiple Output ◽  
High Order Statistics

MIMO radar (Multiple input multiple output radar) is a hot topic which gets lots of attention from researchers all around the world recently. It can achieve better detection performance than conventional phased radar. In this paper, the MIMO radar signal model is studied, and then the concept of MIMO radar is applied into SAR. The technique is employed to detect the oil spill in sea. At last, some conclusion is drawn. And some item for future research in presented also.

scholarly journals What Role Do Intelligent Reflecting Surfaces Play in Non-Orthogonal Multiple Access?

2020 ◽  
Author(s):  
Arthur Sousa de Sena ◽  
Pedro Nardelli
Keyword(s):  
Communication Networks ◽  
Massive Mimo ◽  
Multiple Access ◽  
Multiple Input Multiple Output ◽  
Future Research ◽  
Data Rates ◽  
Input Multiple Output ◽  
Reflecting Surfaces ◽  
Key Techniques ◽  
Performance Gains

Massive multiple-input multiple-output (MIMO) and non-orthogonal multiple access (NOMA) are two key techniques for enabling massive connectivity in future wireless networks. A massive MIMO-NOMA system can deliver remarkable spectral improvements and reduced communication latency. Nevertheless, the uncontrollable stochastic behavior of the wireless channels can still degrade its performance. In this context, intelligent reflecting surface (IRS) has arisen as a promising technology for smartly overcoming the harmful effects of the wireless environment. The disruptive IRS concept of controlling the propagation channels via software can provide attractive performance gains to the communication networks, including higher data rates, improved user fairness, and, possibly, higher energy efficiency. In this article, in contrast to the existing literature, we demonstrate the main roles of IRSs in MIMO-NOMA systems. Specifically, we identify and perform a comprehensive discussion of the main performance gains that can be achieved in IRS-assisted massive MIMO-NOMA (IRS-NOMA) networks. We outline exciting futuristic use case scenarios for IRS-NOMA and expose the main related challenges and future research directions. Furthermore, throughout the article, we support our in-depth discussions with representative numerical results.

Design and Analysis of Rectangular Microstrip Patch Array Antenna on 28 GHz Band for Future of 5G

2021 ◽  
pp. 25-43
Author(s):  
Ashraf Aboshosha ◽  
Mohamed B. El-Mashade ◽  
Ehab A. Hegazy
Keyword(s):  
Low Cost ◽  
Multiple Input Multiple Output ◽  
Array Antenna ◽  
Spectrum Efficiency ◽  
Microstrip Patch ◽  
Fifth Generation ◽  
Data Rates ◽  
Input Multiple Output ◽  
Mobile Phone Applications ◽  
Mm Waves

The narrow beam widths generally associated with antennas at higher frequencies has led to the study of using advanced multiple-input multiple-output (MIMO) and adaptive beam-forming. These antenna technologies are overcoming some of the challenging propagation characteristics of mm waves and could increase the spectrum efficiency, provide higher data rates, and adequate reasonable coverage for mobile broadband services. With the potential for higher 10+GHz frequencies as well as mm waves deployment, most 5G candidates bands in 20 to 50 GHz. The frequency band of 5G is proposed and demonstrated above 24GHz such as 28GHz to 38GHz. In this chapter, the authors present a design of 28GHz for 4 Elements microstrip patch array antenna for future fifth generation (5G) mobile-phone applications. The designed antenna can be implemented using low cost FR-4 substrates, while maintaining good performance in terms of gain and efficiency. In addition, the simulated results show that the antenna has the S11 response less than -10 dB in the frequency range of 22 to 34 GHz.

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