scholarly journals A Hybrid Spectrum Access Strategy with Channel Bonding and Classified Secondary User Mechanism in Multichannel Cognitive Radio Networks

Sensors ◽  
2019 ◽  
Vol 19 (20) ◽  
pp. 4398
Author(s):  
Yuan Zhao ◽  
Minglei Peng ◽  
Jiemin Liu
Keyword(s):  
Cognitive Radio ◽  
Cognitive Radio Networks ◽  
Markov Chain Model ◽  
Transmission Efficiency ◽  
Radio Networks ◽  
Chain Model ◽  
Spectrum Access ◽  
Spectrum Utilization ◽  
Secondary Users ◽  
Channel Bonding

Cognitive radio networks (CRNs) can improve spectrum utilization by allowing secondary users (SUs) to dynamically access channels unoccupied by primary users (PUs). The spectrum access strategy, as a point to enhance user performance, has received much attention. In this paper, we propose a hybrid access mode for network users in multichannel CRNs. For meeting different SU demands, SUs are classified as SU1s and SU2s. We further introduce a channel bonding scheme for high-priority (PU and SU1) user packets to enhance transmission efficiency. At the same time, we propose a hybrid spectrum access strategy for SU2 packets to improve their transmission stability. By establishing a Markov chain model, some important SU2 packets’ performance measures are derived. Furthermore, we display the comparison of hybrid, overlay and underlay modes by numerical results to analyze the advantages of different modes.

Channel Reservation Strategies for Multiple Secondary Users in Cognitive Radio Networks

2014 ◽  
Vol 989-994 ◽  
pp. 3889-3892
Author(s):  
Qiang Peng ◽  
Yan Jiang ◽  
Gan Liu ◽  
Fei Cui ◽  
Guo Bao He ◽  
...  
Keyword(s):  
Cognitive Radio ◽  
Cognitive Radio Networks ◽  
Markov Chain Model ◽  
Radio Networks ◽  
Chain Model ◽  
Spectrum Access ◽  
Secondary Users ◽  
Channel Reservation ◽  
Access Problem ◽  
Qos Guarantees

In cognitive radio networks (CRNs), improving the performance of SUs is the main aspect of present study. In this paper, we focus on the optimal access strategy to provide QoS guarantees for multi-services. The contribution of this paper is as follows. Firstly, we formulate and solve the optimal spectrum access problem with different channel reservation scheme. Secondly, we take account of buffer for handoff secondary users and propose a handoff scheme for multi-services. In addition, the computation complexity of solving the optimal channel reservation problem is simplified by a binary search. The system is analyzed using a continuous-time Markov chain model. The numerical results confirm the validity of the proposed scheme.

scholarly journals Performance Evaluation of Cognitive Radio Networks with Imperfect Spectrum Sensing and Bursty Primary User Traffic

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Osama Salameh ◽  
Herwig Bruneel ◽  
Sabine Wittevrongel
Keyword(s):  
Cognitive Radio ◽  
Cognitive Radio Networks ◽  
Markov Chain Model ◽  
Primary User ◽  
Radio Networks ◽  
Arrival Process ◽  
False Alarms ◽  
Chain Model ◽  
Secondary Users ◽  
Primary Users

In this paper, we introduce a four-dimensional continuous-time Markov chain model to evaluate the performance of cognitive radio networks. In such networks, secondary (unlicensed) users may opportunistically use the frequency channels not currently occupied by primary (licensed) users in order to increase the utilization of the wireless spectrum. Secondary users perform channel sensing before as well as during transmission in order not to interfere with primary users. The proposed model assumes that primary users arrive according to a bursty arrival process and moreover takes the possible occurrence of sensing errors (false alarms and misdetections) into account. Several performance measures including the collision rate between primary and secondary users, the blocking probabilities of primary or secondary users, and the mean delay of secondary users are derived and illustrated through numerical examples. The results show that the system performance strongly depends on the degree of burstiness in the arrival process of primary users. It is also observed that the quality of service of the primary network can be seriously compromised due to misdetection by secondary users.

Asynchronous Channel Allocation in Opportunistic Cognitive Radio Networks

2015 ◽  
pp. 388-426
Author(s):  
Sylwia Romaszko ◽  
Petri Mähönen
Keyword(s):  
Cognitive Radio ◽  
Cognitive Radio Networks ◽  
Channel Allocation ◽  
Optimal Solution ◽  
Radio Networks ◽  
Traffic Patterns ◽  
Spectrum Access ◽  
Secondary Users ◽  
Channel Parameters ◽  
Channel Service

In the case of Opportunistic Spectrum Access (OSA), unlicensed secondary users have only limited knowledge of channel parameters or other users' information. Spectral opportunities are asymmetric due to time and space varying channels. Owing to this inherent asymmetry and uncertainty of traffic patterns, secondary users can have trouble detecting properly the real usability of unoccupied channels and as a consequence visiting channels in such a way that they can communicate with each other in a bounded period of time. Therefore, the channel service quality, and the neighborhood discovery (NB) phase are fundamental and challenging due to the dynamics of cognitive radio networks. The authors provide an analysis of these challenges, controversies, and problems, and review the state-of-the-art literature. They show that, although recently there has been a proliferation of NB protocols, there is no optimal solution meeting all required expectations of CR users. In this chapter, the reader also finds possible solutions focusing on an asynchronous channel allocation covering a channel ranking.

scholarly journals A Survey onadvances in security threats and its counter measures in cognitive radio networks

2018 ◽  
Vol 7 (2.8) ◽  
pp. 372 ◽  
Author(s):  
D Ganesh ◽  
T Pavan Kumar
Keyword(s):  
Cognitive Radio ◽  
Cognitive Radio Networks ◽  
Dynamic Spectrum Access ◽  
Radio Networks ◽  
Cognitive Networks ◽  
Dynamic Spectrum ◽  
Future Research ◽  
Spectrum Utilization ◽  
Secondary Users ◽  
Open Problems

Cognitive radio is a promising wireless communication technology that improves spectrum utilization and offers many benefits for internet users. Cognitive radio networks utilizes the available limited resources in a more efficient and flexible way. The main objective of the Cognitive network is to efficiently utilize the unutilized spectrum and meet the demand of the secondary users. some of the important features of cognitive of Cognitive radio networks are dynamic spectrum access, self organizing  and flexibility. As Cognitive radio networks are flexible in nature, it will be effected by various security attacks which in turn affects the performance of the network. Furthermore Cognitive radio networks transmit the spectrum in several licensed bands and it also performs dynamic spectrum allocation. Cognitive radio and Cognitive radio networks are wireless in nature these face conventional attacks. In this survey we address various  attacks in different layers , new threats and challenges that Cognitive networks face, current available solutions to address layer attacks. In addition applications, open problems and future Research challenges are also specified.

Towards Security Issues and Solutions in Cognitive Radio Networks

2015 ◽  
pp. 813-834
Author(s):  
Saed Alrabaee ◽  
Mahmoud Khasawneh ◽  
Anjali Agarwal
Keyword(s):  
Cognitive Radio ◽  
Cognitive Radio Networks ◽  
Radio Networks ◽  
Network Technology ◽  
Spectrum Utilization ◽  
Secondary Users ◽  
Security Issues ◽  
Primary Users ◽  
Radio Technology ◽  
Cognitive Radio Technology

Cognitive radio technology is the vision of pervasive wireless communications that improves the spectrum utilization and offers many social and individual benefits. The objective of the cognitive radio network technology is to use the unutilized spectrum by primary users and fulfill the secondary users' demands irrespective of time and location (any time and any place). Due to their flexibility, the Cognitive Radio Networks (CRNs) are vulnerable to numerous threats and security problems that will affect the performance of the network. Little attention has been given to security aspects in cognitive radio networks. In this chapter, the authors discuss the security issues in cognitive radio networks, and then they present an intensive list of the main known security threats in CRN at various layers and the adverse effects on performance due to such threats, and the current existing paradigms to mitigate such issues and threats. Finally, the authors highlight proposed directions in order to make CRN more authenticated, reliable, and secure.

scholarly journals Session based cooperation in cognitive radio networks: network level approach

2020 ◽  
Vol 9 (1) ◽  
pp. 40
Author(s):  
Sunil Ghildiyal
Keyword(s):  
Resource Allocation ◽  
Cognitive Radio ◽  
Cognitive Radio Networks ◽  
Spectrum Sharing ◽  
Radio Networks ◽  
Spectrum Access ◽  
Secondary Users ◽  
Generation Spectrum ◽  
Primary Users ◽  
Present Generation

<p>The cognitive radio prototype performance is to alleviate the scarcity of spectral resources for wireless communication through intelligent sensing and quick resource allocation techniques. Secondary users (SU’s) actively obtain the spectrum access opportunity by supporting primary users (PU’s) in cognitive radio networks (CRNs). In present generation, spectrum access is endowed through cooperative communication based link-level frame-based cooperative (LLC) principle. In this SUs independently act as conveyors for PUs to achieve spectrum access opportunities. Unfortunately, this LLC approach cannot fully exploit spectrum access opportunities to enhance the throughput of CRNs and fails to motivate PUs to join the spectrum sharing processes. Therefore to overcome this con, network level cooperative (NLC) principle was used, where SUs are integrated mutually to collaborate with PUs session by session, instead of frame based cooperation for spectrum access opportunities. NLC approach has justified the challenges facing in LLC approach. In this paper we make a survey of some models that have been proposed to tackle the problem of LLC. We show the relevant aspects of each model, in order to characterize the parameters that we should take in account to achieve a spectrum access opportunity.</p>

scholarly journals Spectrum Handoff in Cognitive Radio Networks: A Survey

2017 ◽  
Vol 10 (04) ◽  
pp. 765-772 ◽  
Author(s):  
Nisar Lala ◽  
Altaf Balkhi ◽  
G M Mir
Keyword(s):  
Cognitive Radio ◽  
Cognitive Radio Networks ◽  
Primary User ◽  
Radio Networks ◽  
Spectrum Utilization ◽  
Secondary Users ◽  
Spectrum Handoff ◽  
Suitable Target ◽  
Promising Solution ◽  
Minimum Performance

Cognitive radio (CR) is a promising solution to improve the spectrum utilization by enabling unlicensed users to exploit the spectrum in an opportunistic manner. Spectrum handoff is a different type of handoff in CR necessitated by the reappearance of primary user (PU) in the licensed band presently occupied by the secondary users (SUs). Spectrum handoff procedures aim to help the SUs to vacate the occupied licensed spectrum and find suitable target channel to resume the unfinished transmission. The purpose of spectrum mobility management in cognitive radio networks is to make sure that the transitions are made smoothly and rapidly such that the applications running on a cognitive user perceive minimum performance degradation during a spectrum handoff. In this paper, we will survey the literature on spectrum handoff in cognitive radio networks.

scholarly journals Efficient Advanced Encryption Standard for Securing Cognitive Radio Networks

2018 ◽  
Vol 37 (4) ◽  
pp. 645-654 ◽  
Author(s):  
Maria Saher ◽  
Asjad Amin ◽  
Imran Ali Qureshi ◽  
Muhammad Ali Qureshi ◽  
Muhammad Moazzam Jawaid
Keyword(s):  
Cognitive Radio ◽  
Cognitive Radio Networks ◽  
Computational Efficiency ◽  
Radio Networks ◽  
Advanced Encryption Standard ◽  
Security Threats ◽  
Key Generation ◽  
Wireless Technology ◽  
Spectrum Utilization ◽  
Secondary Users

During the last decade, the CR (Cognitive Radio) came into view as a major wireless technology to resolve the issue of spectrum secrecy and efficient spectrum utilization. However, due to unlicensed (secondary) users, there are various security threats to the CRN (Cognitive Radio Networks). Some malicious users may access the CRN and mislead the secondary users to vacate the occupied channel, which may stop the communication. In this work, we propose a new cryptographic-based algorithm, CRAES (Cognitive Radio-Advanced Encryption Standard), inspired by the traditional AES to secure the CRN. The data of the primary and secondary users is encrypted at the transmitter and decrypted at the receiver. Unlike the conventional AES, we introduce the data-dependent key-generation and shift-rows process. We also reduce the rounds of AES from 10-6 to improve the computational efficiency without compromising the overall security. The experimental results demonstrate the effectiveness of the proposed CR-AES in terms of better security, reliability, and computational efficiency.

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