scholarly journals On optimal number of cognitive radios considering co-site electromagnetic compatibility

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Mingxue Liao
Keyword(s):  
Cognitive Radio ◽  
Wireless Communication ◽  
Electromagnetic Interference ◽  
Electromagnetic Compatibility ◽  
Cognitive Radios ◽  
Optimal Number ◽  
Integral Model ◽  
Radio System ◽  
Spectrum Holes ◽  
Cognitive User

AbstractWith the development and wide applications of wireless communication technology, the limited spectrum resources and the fixed spectrum allocation policy could no longer satisfy the demand for wireless communication. Just for this reason, many spectrum resources become spectrum holes because they are allocated but not used. Cognitive radio is now becoming one of the most important techniques for high utility of these spectrum holes. If the holes available to cognitive users are abundant over a certain time, it is a worth consideration to increase network throughputs by orthogonal multiplexing as many as spectrum holes. A multi-transceiver configuration is one of the possible solutions for this purpose. With such a schema, all transceivers within a cognitive user work in a concurrent or parallel mode, by which the throughput of the network can be increased. However, co-site working cognitive radios may incur electromagnetic interference between each other. When more cognitive radios are equipped, much electromagnetic interference may be incurred. Many techniques are proposed to mitigate such so-siting interference; however, none of them have addressed the probability that the interference will happen. If the probability could be estimated in advance, the user will make a better planning on the configurations of the co-siting working radios. Based on an elaborated n-fold multiple integral model, we propose a novel method to decide how many cognitive radios can be installed for one cognitive user at most. This is our main contribution with this work, providing an enhanced ability to determine the optimal number of cognitive radios installed within each cognitive user. We make a strict deduction on electromagnetic compatibility probability with various parameters of cognitive radios. Simulations are performed and the results show that the electromagnetic compatibility of the simulated cognitive radio system meets the deducted probability by this method very well.

scholarly journals On Optimal Number of Cognitive Radios Considering Co-site Electromagnetic Compatibility

2021 ◽  
Author(s):  
Mingxue Liao
Keyword(s):  
Cognitive Radio ◽  
Electromagnetic Interference ◽  
Electromagnetic Compatibility ◽  
Cognitive Radios ◽  
Optimal Number ◽  
Radio System ◽  
Parallel Mode ◽  
Spectrum Holes ◽  
High Utility ◽  
Cognitive User

Abstract Cognitive radio is becoming one of the most important techniques for high utility of spectrum holes. If the holes available to cognitive users are abundant over a certain time, it is a worth consideration to increase network throughputs by orthogonal multiplexing as many as spectrum holes. A multi-transceiver configuration is one of the possible solutions for this purpose. With such a schema, all transceivers within a cognitive user work in a concurrent or parallel mode, by which the throughput of the network can be increased. However, co-site working cognitive radios may incur electromagnetic interference between each other. When more cognitive radios are equipped, much electromagnetic interference may be incurred. Based on an electromagnetic compatibility probability analysis, this paper proposes a novel method to decide how many cognitive radios can be installed for one cognitive user at most. We make a strict deduction on electromagnetic compatibility probability with various parameters of cognitive radios. Simulations are performed and the results show that the electromagnetic compatibility of the simulated cognitive radio system meet the deducted probability very well.

Anti-Interference Communication Based on Cognitive Radio

2013 ◽  
Vol 475-476 ◽  
pp. 843-846
Author(s):  
Hong Xu Huang
Keyword(s):  
Cognitive Radio ◽  
Communication Technology ◽  
Future Research ◽  
Radio System ◽  
The Future ◽  
The Difference ◽  
Cognitive User ◽  
Research Situation

Firstly Cognitive radio (CR) communication technology is introduced. Then the current research situation of CR-based anti-interference communication are reviewed and analyzed. The two CR-based anti-interference radio structures are given. Then CR-based anti-interference transceivers are introduced and analyzed. Further analysis shows that the future research for CR-based anti-interference radio system should consider the difference between anti-interference user and cognitive user, more environment information interceptions and the combinations of CR and other anti-interference technologies.

Cognitive Radios Exploiting Gray Spaces via Compressed Sensing

Frequenz ◽  
2016 ◽  
Vol 70 (7-8) ◽  
Author(s):  
Dennis Wieruch ◽  
Peter Jung ◽  
Thomas Wirth ◽  
Armin Dekorsy ◽  
Thomas Haustein
Keyword(s):  
Cognitive Radio ◽  
Compressed Sensing ◽  
Cognitive Radios ◽  
Radio System ◽  
Cognitive Radio System

AbstractWe suggest an interweave cognitive radio system with a

scholarly journals Throughput Analysis of Opportunistic Channel Access Techniques in Cognitive Radio Systems

2021 ◽  
Author(s):  
Sivasothy Sen Senthuran
Keyword(s):  
Cognitive Radio ◽  
Primary User ◽  
Rate Performance ◽  
Radio System ◽  
Cognitive Radio System ◽  
Primary Users ◽  
Cognitive Radio Systems ◽  
Radio Systems ◽  
Cognitive User

In recent studies it was found out that previously allocated frequency spectrum is not fully utilized in all the wireless systems. Cognitive radio is the new concept to access this underutilized spectrum and, also a promising technology to cope with the ever increasing bandwidth demand for next generation wireless networks. Cognitive radio network can be classified into three different categories: interweave, underlay and overlay. In an interweave cognitive radio system, the unoccupied spectrum holes can be shared by cognitive users with minimal collision with primary users (spectrum owners) whereas in an underlay system, concurrent transmission is allowed with an interference threshold to the primary users. In an underlay system, cognitive users generally transmit at very low power. In an overlay system, cognitive users, similar to underlay cognitive radio systems, concurrently transmit with primary users but cognitive users may know the codewords of the primary transmitter. Hence, using that knowledge, cognitive transmitter may adopt different coding techniques to cancel/mitigate the interference at the primary receiver and/or it may assist the primary system by relaying primary user’s data. In this thesis, we improve the throughput/bit error rate performance of a cognitive radio system by effectively accessing the channels. Throughout the thesis we assume that cognitive user can sense only one channel at a time and we analyze the performance with perfect and imperfect sensing. First, we propose a novel opportunistic access scheme for cognitive radios in an interweave cognitive system, that considers the channel gain as well as the predicted idle channel probability (primary user occupancy: busy/idle). In contrast to previous work where a cognitive user vacates a channel only when that channel becomes busy, the proposed scheme requires the cognitive user to switch to the channel with the next highest idle probability if the current channel’s gain is below a certain threshold. We derive the threshold values that maximize the long term throughput for various primary user transition probabilities and cognitive user’s relative movement (Doppler spread). Then, we propose a three state Markov model to analyze the performance of a hybrid interweave-underlay system where the primary user’s occupancy states are hidden, but their activity statistics, ranges of transmission, and interference thresholds are known. The primary user is assumed to be in one of the three transmission modes as seen by the cognitive user: busy, concurrent and idle. We derive the transmission mode selection criteria (interweave/underlay) to improve the long term throughput of a cognitive user based on the primary user traffic characteristics and the achievable throughput ratio between the two modes of operation. Later, we incorporate the sensing error in our analysis where we study the optimal access strategy. Since the optimal policy requires the channel to be sensed in each time-slot, we propose and analyze a forward algorithm based cross-layer frame based sensing policy. Finally, we focus on the overlay cognitive radio system where cognitive relay nodes assist the primary transmission. As an initial study, we select a two-hop decode-and-forward orthogonal frequency and code division multiplexing based relay network. For this system, we propose adaptive channel allocation and, power allocation strategies and the bit error rate performance is numerically evaluated. This preliminary analysis can be extended to overlay cognitive systems.

scholarly journals Throughput Analysis of Opportunistic Channel Access Techniques in Cognitive Radio Systems

2021 ◽  
Author(s):  
Sivasothy Sen Senthuran
Keyword(s):  
Cognitive Radio ◽  
Primary User ◽  
Rate Performance ◽  
Radio System ◽  
Cognitive Radio System ◽  
Primary Users ◽  
Cognitive Radio Systems ◽  
Radio Systems ◽  
Cognitive User

In recent studies it was found out that previously allocated frequency spectrum is not fully utilized in all the wireless systems. Cognitive radio is the new concept to access this underutilized spectrum and, also a promising technology to cope with the ever increasing bandwidth demand for next generation wireless networks. Cognitive radio network can be classified into three different categories: interweave, underlay and overlay. In an interweave cognitive radio system, the unoccupied spectrum holes can be shared by cognitive users with minimal collision with primary users (spectrum owners) whereas in an underlay system, concurrent transmission is allowed with an interference threshold to the primary users. In an underlay system, cognitive users generally transmit at very low power. In an overlay system, cognitive users, similar to underlay cognitive radio systems, concurrently transmit with primary users but cognitive users may know the codewords of the primary transmitter. Hence, using that knowledge, cognitive transmitter may adopt different coding techniques to cancel/mitigate the interference at the primary receiver and/or it may assist the primary system by relaying primary user’s data. In this thesis, we improve the throughput/bit error rate performance of a cognitive radio system by effectively accessing the channels. Throughout the thesis we assume that cognitive user can sense only one channel at a time and we analyze the performance with perfect and imperfect sensing. First, we propose a novel opportunistic access scheme for cognitive radios in an interweave cognitive system, that considers the channel gain as well as the predicted idle channel probability (primary user occupancy: busy/idle). In contrast to previous work where a cognitive user vacates a channel only when that channel becomes busy, the proposed scheme requires the cognitive user to switch to the channel with the next highest idle probability if the current channel’s gain is below a certain threshold. We derive the threshold values that maximize the long term throughput for various primary user transition probabilities and cognitive user’s relative movement (Doppler spread). Then, we propose a three state Markov model to analyze the performance of a hybrid interweave-underlay system where the primary user’s occupancy states are hidden, but their activity statistics, ranges of transmission, and interference thresholds are known. The primary user is assumed to be in one of the three transmission modes as seen by the cognitive user: busy, concurrent and idle. We derive the transmission mode selection criteria (interweave/underlay) to improve the long term throughput of a cognitive user based on the primary user traffic characteristics and the achievable throughput ratio between the two modes of operation. Later, we incorporate the sensing error in our analysis where we study the optimal access strategy. Since the optimal policy requires the channel to be sensed in each time-slot, we propose and analyze a forward algorithm based cross-layer frame based sensing policy. Finally, we focus on the overlay cognitive radio system where cognitive relay nodes assist the primary transmission. As an initial study, we select a two-hop decode-and-forward orthogonal frequency and code division multiplexing based relay network. For this system, we propose adaptive channel allocation and, power allocation strategies and the bit error rate performance is numerically evaluated. This preliminary analysis can be extended to overlay cognitive systems.

Cognitive Radio Network for E-Health Systems

2019 ◽  
pp. 281-298
Author(s):  
Shashank Gupta ◽  
Shikha Singhal ◽  
Adwitiya Sinha
Keyword(s):  
Cognitive Radio ◽  
Ubiquitous Computing ◽  
Electromagnetic Interference ◽  
Cognitive Radios ◽  
Collaborative Study ◽  
Hospital Environment ◽  
Health State ◽  
Wireless Devices ◽  
Sensitive Data ◽  
Wireless Technologies

The world is witnessing widespread roots of ubiquitous computing across disciplines and industries. It is equipped with the ability to monitor anything from anywhere with efficient, easy, and equitable goods that offer services for everyone. This has become possible through usage of wireless technologies, which possess an extensive scope in healthcare domain. However, despite various advantages, wireless technologies are faced with distinct challenges in hospital environment. For instance, wireless devices often tend to cause electromagnetic interference to critical medical devices resulting in malfunctioning. Further, with ubiquitous computing, sensitive data about health state of patients is constantly being shared remotely from one place to another. Therefore, systems in place must address requirements of data security, and thus privacy. For this purpose, the chapter presents a collaborative study on cognitive-radio-based healthcare system, including advantages, architecture, and challenges related to implementation of cognitive radios in hospital environment.

scholarly journals ELECTROMAGNETIC COMPATIBILITY OF RES ON RAILWAY

2020 ◽  
pp. 7-22
Author(s):  
Popov V ◽  
Shevchenko A
Keyword(s):  
Communication Networks ◽  
Mobile Communication ◽  
Electromagnetic Interference ◽  
Electromagnetic Compatibility ◽  
Rolling Stock ◽  
Radio System ◽  
Mobile Communication Networks ◽  
High Level ◽  
Cellular Mobile ◽  
Cellular Mobile Communication

This work reviews the main related problems of electromagnetic compatibility (EMC) of the locomotive radio system GSM-R in modern railway transport. The typical internal electromagnetic interference (EMI), caused by the high density of the equipment layout in the rolling stock, and external electromagnetic interference generated by public cellular mobile communication networks and other radio systems are considered. The results of experiments to determine the parameters of public cellular mobile communication networks along the selected railway section show a rather high level of signals that are EMI for GSM-R and affecting on EMC.

scholarly journals Reducing Spectrum Handoffs and Energy Switching Consumption of MADM-Based Decisions in Cognitive Radio Networks

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Rafael Aguilar-Gonzalez ◽  
Marco Cardenas-Juarez ◽  
Ulises Pineda-Rico ◽  
Armando Arce ◽  
Matti Latva-aho ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Cognitive Radio ◽  
Life Time ◽  
Battery Life ◽  
Real Spectrum ◽  
Channel Switching ◽  
Secondary Users ◽  
Multiple Attribute ◽  
Spectrum Holes ◽  
Cognitive User

In a cognitive radio network (CRN), the number of spectrum handoffs increases energy consumption of cognitive (or secondary) users due to the channel switching process. This might limit the operation of the CRN, especially in scenarios where secondary users terminals are battery-powered. Thus, reducing the number of times a cognitive user involved in a transmission switch to different spectrum holes is required to increase battery life-time. In this regard, available spectrum holes possess different attributes (e.g., bandwidth) that can be exploited to satisfy specific secondary users requirements (i.e., connection profile) for data transmission while saving energy. Here, three multiple attribute decision-making (MADM) algorithms for the spectrum decision functionality are evaluated using real spectrum measurements of TV bands. This is performed by proposing six decision parameters, which are extracted from the spectrum data to characterize its suitability. Then, these are used as inputs of the MADM algorithms to select the most suitable spectrum hole for a cognitive user. Thus, an enhanced MADM-based decision process is proposed to reduce the number of handoffs considering energy consumption due to channel switching (ECCS). Results quantify savings from 30% to 90% in ECCS and spectrum handoffs reductions from 47% to 90%.

Adaptive and Distributed Access to Spectrum Holes in Cognitive Radio System

2012 ◽  
Vol 70 (1) ◽  
pp. 207-226 ◽  
Author(s):  
Kae Won Choi ◽  
Wha Sook Jeon ◽  
Dong Geun Jeong
Keyword(s):  
Cognitive Radio ◽  
Radio System ◽  
Cognitive Radio System ◽  
Spectrum Holes
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