Improved local spectrum sensing in cluttered environment using a simple recursive estimator

In the context of the currently developed networks for the realization of future communications, the concept of Cognitive Radio (CR) has a significant place. Its implementation in modern ultra-dense networks (UDN) requires the development of novel and improved adaptive solutions for the main functionalities of a CR system. This technology has a great potential for solving the significant spectrum underutilization issue which has been established as characteristic for the traditional communication networks and hence, the continual and substantive research efforts in the recent years. The principal challenge for CRs is the optimization of spectrum utilization without creating unwanted interference for the incumbent (primary) users. Thus, a significant portion of the research is directed towards the vital spectrum sensing functionality. This paper reviews the potential uses of CR in UDN as well as the main approaches for modeling of spectrum sensing with respect to signal detection. The review focuses on local spectrum sensing techniques and presents the strengths and weaknesses of their mathematical definition. Specific attention is given to the channel models which are considered in the literature and to what kinds of features are extracted from the received signal to achieve accurate detection.

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Sensing Confidence Level-Based Cooperative Spectrum Sensing Algorithm

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.380-384.1499 ◽

2013 ◽

Vol 380-384 ◽

pp. 1499-1504

Author(s):

Shi Ding Zhang ◽

Hai Lian Wang ◽

Jing Ping Mei

Keyword(s):

False Alarm ◽

Spectrum Sensing ◽

Confidence Level ◽

Detection Probability ◽

Cooperative Spectrum Sensing ◽

False Alarm Probability ◽

Control Channel ◽

Fusion Center ◽

Local Spectrum ◽

Secondary Users

Cooperative spectrum sensing is a key technology to tackle the challenges such as fading or hidden terminal problem in local spectrum sensing of cognitive radio system. Conventional cooperative method can improve the detection performance in some sense, but increase overhead of control channel. In order to reduce the overhead, a new cooperative spectrum sensing algorithm based on confidence level is proposed. In this algorithm, the maximum-eigenvalue-based detection scheme is carried out to obtain the local spectrum detection and the detection probability and false alarm probability of each secondary user are used to estimate the reliability of the sensing decision. The test statistic of the secondary users with high reliability are chosen and sent to fusion center. Then weighted factors of chosen secondary users are derived from creditability values, and the global decision is made by weighted fusion at fusion center. The simulation results show that the proposed algorithm improves the detection probability in the guarantee of the false-alarm probability close to 0 and saves half of the overhead in the control channel.

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A brief attachment perspective on hoarding

Attachment New Directions in Psychotherapy and Relational Psychoanalysis ◽

10.33212/att.v14n2.2020.168 ◽

2020 ◽

Vol 14 (2) ◽

pp. 168-170

Author(s):

Linda Cundy

Keyword(s):

Cluttered Environment

Working online during lockdown, psychotherapists have glimpsed inside their clients' homes and sometimes we see a cluttered environment. This article addresses the difficulty experienced by many people of parting with objects, proposing that we identify with our possessions and invest them with feelings in line with our own experiences.

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Practical Implementation of Spectrum Sensing and Signal Detection for Satellite Broadcasting Systems

IEICE Transactions on Communications ◽

10.1587/transcom.2015ebp3448 ◽

2016 ◽

Vol E99.B (8) ◽

pp. 1894-1901

Author(s):

Hiroyuki KAMATA ◽

Gia Khanh TRAN ◽

Kei SAKAGUCHI ◽

Kiyomichi ARAKI

Keyword(s):

Signal Detection ◽

Spectrum Sensing ◽

Practical Implementation ◽

Satellite Broadcasting

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