scholarly journals SPECTRUM SENSING USING CYCLIC PREFIX IN COGNITIVE RADIO WIRELESS SYSTEM

2013 ◽  
pp. 123-127
Author(s):  
T. NAGAMANI ◽  
M.V. SUDHAKAR ◽  
E. ADINARAYANA
Keyword(s):  
Cognitive Radio ◽  
User Satisfaction ◽  
Wireless Systems ◽  
Energy Detection ◽  
Substantial Improvement ◽  
Cyclic Prefix ◽  
Short Message ◽  
Spectrum Utilization ◽  
Primary Signal

The rapid growth of wireless communications has made the problem of spectrum utilization ever more critical. The increasing diversity (voice, short message, Web & multimedia) and demand of high quality-of-service (QoS) applications have resulted in overcrowding of the allocated (officially sanctioned) spectrum bands, leading to significantly reduced levels of user satisfaction. The concepts of GLRT algorithm and substantial improvement over the U-GLRT algorithm are explained. This paper presents a model which uses efficient CP method for CR in Wireless Systems. Primary signal has been detected in the OFDM transmission with both the CPCC and MP–based C-GLRT algorithms greatly outperform energy detection in multi path environment has been implemented using software design. The signal model in our analysis is to efficiently exploit the correlation among the transmitted signals due to the presence of CP. Proposed method of cognitive radio takes two steps of implementation .first named as MP based is to detect the noise and de-noise the signal and the second is cp based in which the signals are identified based on the cyclic prefix.

scholarly journals Cost-Effective Spectrum Utilization for Futuristic Cognitive Radio based Services

2020 ◽  
Vol 9 (4) ◽  
pp. 2476-2480
Keyword(s):  
Cognitive Radio ◽  
Cost Effective ◽  
Spectrum Allocation ◽  
Transmission Model ◽  
Quality Of Services ◽  
Spectrum Utilization ◽  
False Positive Identification ◽  
Spectrum Scarcity ◽  
Prime Target

The proliferation of various mobile users in the context of advanced wireless technologies, spectrum scarcity arises as a crucial problem. The notion of cognitive radio (CR) principle offers cost-effective spectrum reusability with intelligent mode of transmission model. It basically enables a radio-driven technology to utilize dynamic spectrum accessing to meet the quality-of-services (QoS) requirements by satisfying enormous communication and connectivity demands. To alleviate the spectrum scarcity problem the study proposes a novel analytical solution of spectrum allocation considering a simplified evolutionary learning model. The prime target of the formulated concept is to detects the spectrum holes effectively for reusability and the possibility of identification has be maximized for best possible spectrum allocation to the radios. And on the other hand also the occurrence of false positive identification has to be minimized. The outcome obtained after performing the simulation shows promising aspects in the context of effective spectrum allocation for higher priority user with better throughput performance.

scholarly journals Analysis of Efficient Spectrum Handoff in a Multi-Class Hybrid Spectrum Access Cognitive Radio Network Using Markov Modelling

Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4120 ◽  
Author(s):  
Atif Shakeel ◽  
Riaz Hussain ◽  
Adeel Iqbal ◽  
Irfan Latif Khan ◽  
Qadeer ul Hasan ◽  
...  
Keyword(s):  
Cognitive Radio ◽  
Substantial Improvement ◽  
System Throughput ◽  
Spectrum Access ◽  
Spectrum Utilization ◽  
Markov Modelling ◽  
Spectrum Handoff ◽  
Delay Sensitive ◽  
Primary Network ◽  
The Impact

Cognitive radio networks (CRNs) rely on sensing of the licensed spectrum of a primary network to dynamically ascertain underutilized portion of the spectrum, thus affording additional communication opportunities. In a CRN, a single homogeneous spectrum access, such as interweave only deprives the secondary users (SUs) of channel access during handoff, particularly at high primary network traffic. Therefore, providing quality-of-service (QoS) to multi-class SUs with diverse delay requirements during handoff becomes a challenging task. In this paper, we have evolved a Markov-based analytical model to ascertain the gain in non-switching spectrum handoff scheme for multi-class SUs employing hybrid interweave-underlay spectrum access strategy. To satisfy the QoS requirements of the delay-sensitive traffic, we have analyzed the impact of hybrid spectrum access scheme for prioritized multi-class SUs traffic. The results show substantial improvement in spectrum utilization, average system throughput and extended data delivery time compared to conventional CRN using interweave only spectrum access. This demonstrates the suitability of the proposed scheme towards meeting QoS requirements of the delay-sensitive SU traffic while improving the overall performance for delay-tolerant SU traffic as well.

Analysis of Spectrum Sensing in Cognitive Radio Network with OFDM

2018 ◽  
Vol 8 (6) ◽  
pp. 84
Author(s):  
Shadab Ahmed Khan ◽  
Pawandeep Kaur
Keyword(s):  
Cognitive Radio ◽  
Spectrum Sensing ◽  
Cognitive Radio Network ◽  
Energy Detection ◽  
Radio Spectrum ◽  
Probability Of Detection ◽  
Spectrum Utilization ◽  
Wireless Applications ◽  
Novel Technology ◽  
Cognitive Environment

With the development of a new and ever expanding wireless applications and services, spectrum resources are facing in demands. In present scenario, the spectrum allotment has been done by providing each new service with its own fixed frequency Slot. Most of the user’s spectrum is already assigned, so it becomes very difficult to find spectrum for other users or existing users. This leads to the scarcity of available spectrum and inefficient channel utilization. Cognitive radio is a novel technology which improves the spectrum utilization by allowing secondary user to borrow unused radio spectrum from primary licensed users or to share the spectrum with the primary users. Present paper deals with the spectrum sensing in which multiple users detect the spectrum gap through energy detection and investigate the detection performance in an efficient and implementable way. Simulation results showed that the probability of detection is achieved at small value SNR in case of OFDM modulation as compare the other and simple cognitive environment.

scholarly journals Simulation and Analysis of the OFDM Transceiver Based Commutation System

2020 ◽  
Vol 26 (12) ◽  
pp. 131-140
Author(s):  
Areej Munadel ◽  
Ekhlas Kadhum Hamza
Keyword(s):  
Cognitive Radio ◽  
Signal To Noise Ratio ◽  
Radio Spectrum ◽  
Cyclic Prefix ◽  
Probability Of Detection ◽  
Energy Detector ◽  
Signal To Noise ◽  
Wireless Applications ◽  
Low Snr

As a result of the increase in wireless applications, this led to a spectrum problem, which was often a significant restriction. However, a wide bandwidth (more than two-thirds of the available) remains wasted due to inappropriate usage. As a consequence, the quality of the service of the system was impacted. This problem was resolved by using cognitive radio that provides opportunistic sharing or utilization of the spectrum. This paper analyzes the performance of the cognitive radio spectrum sensing algorithm for the energy detector, which implemented by using a MATLAB Mfile version (2018b). The signal to noise ratio SNR vs. Pd probability of detection for OFDM and SNR vs. BER with CP cyclic prefix with energy detector is calculated and analyzed. In this paper, the proposed work produces more accurate results compared to the existing techniques at low SNR values.

An Overview of Cognitive Radio Networks

2019 ◽  
pp. 1-26 ◽  
Author(s):  
Pooja Joshi ◽  
Ashish Bagwari
Keyword(s):  
Cognitive Radio ◽  
Software Defined Radio ◽  
Network Architecture ◽  
Wireless Systems ◽  
Radio Spectrum ◽  
Frame Structure ◽  
Area Network ◽  
Spectrum Utilization ◽  
New Paradigm ◽  
Regional Area

The major hurdle that restricts the efficient utilization of radio spectrum is its inflexible and rigid licensing scheme. This constraint limits the emerging wireless systems to operate in static spectrum band. This deficiency compelled the innovators to introduce new paradigm (i.e., cognitive radio [CR] technique to boost productive spectrum utilization). In this chapter, the authors briefly introduce the CR to exploit wireless spectrum opportunistically. Cognitive radio network architecture is also discussed in detail. Authors also mentioned the software-defined radio (SDR) platform as a support to regulate spectrum reuse. IEEE 802.22, the first worldwide standard for wireless regional area network (WRAN), based of CR technology is presented in descriptive way along with its capacity, coverage, MAC layer frame structure. It has been observed that CR strikes its presence in today's modern wireless systems, applications, various projects, and trends, and become their desire.

scholarly journals Throughput Analysis for Cooperative Cognitive Radio Networks using Cyclostationary Detection

2021 ◽  
Vol 19 ◽  
pp. 240-248
Author(s):  
Enfel Barkat
Keyword(s):  
Cognitive Radio ◽  
Orthogonal Frequency Division Multiplexing ◽  
Cooperative Spectrum Sensing ◽  
Spectrum Utilization ◽  
Cooperative Cognitive Radio Networks ◽  
Trade Offs ◽  
Primary Signal ◽  
Cyclostationary Detection ◽  
System Overhead ◽  
The Relationship

Detection of primary users (PUs) in the presence of interference and noise and improvement of spectrum utilization is one of the aims of cognitive radio (CR). In this paper, a fully distributed cooperative spectrum sensing scheme based on cyclostationary features techniques is proposed. The primary signal detection is realized by an orthogonal frequency division multiplexing (OFDM) sensing algorithm; each secondary user (SU) makes decisions about the PU by exchanging their own measurements with the local neighbors. The distributed scheme is analyzed on a network layer, where the throughput performance is analyzed in terms of sensing accuracy, frame duration, and system overhead. An analytical expression for the SU throughput is derived, in addition to investigating the issue of trade offs between time and overhead. Simulation results showed the relationship between the throughput and the sensing time, the effect of increasing the number of SUs on the throughput, and the outcome of increasing traffic intensity on the system performance

scholarly journals Evaluating the success of the tele-pathology system in governmental hospitals in Kuwait: an explanatory sequential mixed methods design

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ali Jasem Buabbas ◽  
Tareq Mohammad ◽  
Adel K. Ayed ◽  
Hawraa Mallah ◽  
Hamza Al-Shawaf ◽  
...  
Keyword(s):  
Clinical Practice ◽  
Mixed Methods ◽  
Support Services ◽  
User Satisfaction ◽  
Technical Support ◽  
Successful Implementation ◽  
System Quality ◽  
Mixed Methods Design ◽  
Telepathology System

Abstract Background Telepathology is the practice of reviewing and exchanging pathological images through telecommunication systems to obtain diagnoses remotely. Studying the factors that make such a system successful and favourable is important to ensure the merits of its implementation in clinical practice. Objective This study aims to evaluate the success of a telepathology system from the users’ perspectives, using specific evaluation criteria, namely: system quality, information quality, technical service quality, user satisfaction, and benefits. Methods A sequential explanatory mixed methods design was adopted in this study, which consists of two phases. Initially, a questionnaire was distributed via WhatsApp to all of the pathologists (total: 45) working at governmental hospitals in Kuwait. Followed by, semi-structured interviews with ten senior pathologists. Results Forty pathologists responded to the questionnaire, giving an 89% response rate. There were 42.5% of the respondents aged between 35–44 years old, and 52.5% were male. The quantitative results reveal that most of the respondents were satisfied with the quality of the telepathology system with a mean of 2.6025 (Standard Deviation (SD) = 0.47176), whereas they were dissatisfied with the quality of the information with a mean of 2.4100 (SD = 1.580) and the technical support services with a mean of 2.2750 (SD = 0.99535). In addition, there was disagreement on the benefits of telepathology in clinical practice among the pathologists with a mean of 2.4667 (SD = 0.77552). The qualitative results indicate that the lack of interest in and little experience with using the system were behind the general dissatisfaction of most of the respondents. All of the interviewees were satisfied with the performance of the telepathology system and considered it successful; however, the quality of the technical support services, including training workshops, was deemed deficient. Conclusion This study concluded that telepathology system in Kuwait is functioning well and has been successful in its implementation; however, pathologists are dissatisfied with it, mainly due to the deficient quality of the technical support services provided. In addition, the successful implementation of such advanced technologies requires careful steps to be taken on multiple levels: technical, organisational, and managerial. Recommendations were suggested.

scholarly journals Optimal linear weighted cooperative spectrum sensing for clustered-based cognitive radio networks

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Haiyan Ye ◽  
Jiabao Jiang
Keyword(s):  
Cognitive Radio ◽  
Spectrum Sensing ◽  
Cognitive Radio Networks ◽  
Cooperative Spectrum Sensing ◽  
Radio Networks ◽  
Spectrum Utilization ◽  
Channel Characteristics ◽  
Optimal Linear ◽  
Static Division ◽  
Cooperative Nodes

AbstractThe lack of spectrum resources restricts the development of wireless communication applications. In order to solve the problems of low spectrum utilization and channel congestion caused by the static division of spectrum resource, this paper proposes an optimal linear weighted cooperative spectrum sensing for clustered-based cognitive radio networks. In this scheme, different weight values will be assigned for cooperative nodes according to the SNR of cognitive users and the historical sensing accuracy. In addition, the cognitive users can be clustered, and the users with the better channel characteristics will be selected as cluster heads for gathering the local sensing information. Simulation results show that the proposed scheme can obtain better sensing performance, improve the detection probability and reduce the error probability.

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