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.

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.

The Impact of Regulations on the Business Case for Cognitive Radio

2013 ◽  
pp. 142-170
Author(s):  
Peter Anker
Keyword(s):  
Cognitive Radio ◽  
Potential Application ◽  
Business Case ◽  
Radio Spectrum ◽  
Considerable Degree ◽  
Regulatory Regime ◽  
Spectrum Access ◽  
The Impact

Cognitive Radio holds an interesting promise for improved utilisation of the radio spectrum. However, there is a considerable degree of uncertainty regarding the potential application of cognitive radio. One of the reasons for this uncertainty is the need for changes in the regulatory regime to allow for more dynamic forms of spectrum access. In addressing the necessary changes in regulations, the regulator should be well aware of the perspective of the entrepreneur. Eventually, it is the entrepreneur who invests in CR technology and thereby realises the goal of improved utilisation of the radio spectrum. This chapter addresses the impact on the business case for cognitive technologies of the regulatory regime and the choices on the fundamental CR technology that regulators will have to make.

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 Spectrum handoff analysis for multiple secondary users in cognitive radio networks

2020 ◽  
Vol 20 (1) ◽  
pp. 264
Author(s):  
Ban Bakhtyar Mahmud Shawkat ◽  
Asaad M. Jassim Al-Hindawi ◽  
Akram Hatam Shadir
Keyword(s):  
Cognitive Radio ◽  
System Model ◽  
Data Delivery ◽  
Delivery Time ◽  
Queuing Model ◽  
Secondary Users ◽  
Priority Class ◽  
Spectrum Handoff ◽  
Delay Sensitive ◽  
Preemptive Resume Priority

<p>The cognitive radio network permits secondary users to reach unused spectrum of primary users. In this paper, a mixed preemptive/non-preemptive resume priority M/G/1 queuing model is proposed for characterizing multiple handoff delay and to minimize the extended data delivery time of secondary users that has experienced multiple spectrum handoff during its transmission. The proposed queuing model supports delay-sensitive secondary user applications. The secondary users’ traffic is classified into two priority classes, the highest priority class for delay sensitive services and the lowest priority class for delay insensitive services. Furthermore, the proposed model assigns higher priority for the interrupted secondary users over uninterrupted secondary users for each class of secondary users in order to minimize the handoff delays for secondary users that experience multiple interruptions. Analytical formulas for the average extended data delivery time are derived for two different proactive spectrum handoff strategies (always stay and always change strategies) for both classes of secondary users. Simulation of proposed system model was performed to validate the analytical results and a good agreement was obtained. The performance of the suggested model is assessed and compared with other spectrum handoff models. Numerical results illustrate that the proposed system model outperforms existing models and can reduce the extended data delivery time for the secondary users.</p>

scholarly journals A Robust Cooperative Spectrum Sensing-Assisted Multiuser Resource Allocation Scheme

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Jun Du ◽  
Daoxing Guo ◽  
Bangning Zhang ◽  
Yunxia Su
Keyword(s):  
Resource Allocation ◽  
Cognitive Radio ◽  
Spectrum Sensing ◽  
Cooperative Spectrum Sensing ◽  
Primary User ◽  
System Throughput ◽  
Allocation Scheme ◽  
Spectrum Access ◽  
Primary User Emulation Attack ◽  
Resource Allocation Scheme

Cognitive radio (CR), which is proposed as a solution for spectrum scarcity, imposes some threats to the network. One severe attack to cognitive radio network is the primary user emulation attack (PUEA), in which an attacker may transmit its signal with high power or mimic specific features of the primary user’s signal to prevent secondary users from accessing the licensed spectrum. In this paper, we study a subcarrier and power allocation problem for orthogonal frequency division multiple access-(OFDMA-) based CR systems in the presence of PUEA. To maximize the system throughput while keeping the interference introduced to the primary user (PU) below given thresholds with a certain probability, a joint design of a robust cooperative spectrum sensing and a resource allocation scheme is proposed. In the proposed scheme, the inaccurate classification of PU signals and PUEA signals provided by robust cooperative spectrum sensing is utilized by resource scheduling module. To further exploit the underutilized spectrum bands, we also evaluate the performance of the proposed scheme in the hybrid overlay/underlay spectrum access mechanism. Numerical results demonstrate the effectiveness of the proposed scheme compared to conventional scheme regardless of the number of SUs or the kind of spectrum access mechanism being used.

scholarly journals Throughput Maximization Based on Optimal Access Probabilities in Cognitive Radio System

2021 ◽  
Author(s):  
Lian Zhao
Keyword(s):  
Cognitive Radio ◽  
Primary User ◽  
Throughput Maximization ◽  
System Throughput ◽  
Secondary System ◽  
Spectrum Utilization ◽  
Secondary Users ◽  
Radio System ◽  
Low Efficiency ◽  
Service State

Well-established fact shows that the fixed spectrum allocation policy conveys to the low spectrum utilization. The cognitive radio technique promises to improve the low efficiency. This paper proposes an optimized access strategy combining overlay scheme and underlay scheme for the cognitive radio. We model the service state of the system as a continuous-time Markov model. Based on the service state, the overlay manner or/and the underlay manner is/are used by the secondary users. When the primary user is not transmitting and only one secondary user has the requirement to transmit, the secondary system adopts the overlay scheme. When the primary user is transmitting and the secondary users want to transmit simultaneously, an underlay scheme with an access probability is adopted. We obtain the optimal access probability in a closed form which maximizes the overall system throughput

scholarly journals Interference Alignment in Multi-Hop Cognitive Radio Networks under Interference Leakage

2018 ◽  
Vol 8 (12) ◽  
pp. 2486 ◽  
Author(s):  
Eylem Erdogan ◽  
Sultan Çolak ◽  
Hakan Alakoca ◽  
Mustafa Namdar ◽  
Arif Basgumus ◽  
...  
Keyword(s):  
Cognitive Radio ◽  
Interference Alignment ◽  
Ergodic Capacity ◽  
Secondary Source ◽  
Primary Network ◽  
Secondary Network ◽  
The Impact ◽  
Secondary Networks ◽  
Diversity Gains ◽  
Multiple Primary Users

In this work, we examine the interference alignment (IA) performance of a multi-input multi-output (MIMO) multi-hop cognitive radio (CR) network in the presence of multiple primary users. In the proposed architecture, it is assumed that linear IA is adopted at the secondary network to alleviate the interference between primary and secondary networks. By doing so, the secondary source can communicate with the secondary destination via multiple relays without causing any interference to the primary network. Even though linear IA can suppress the interference in CR networks considerably, interference leakages may occur due to a fast fading channel. To this end, we focus on the performance of the secondary network for two different cases: (i) the interference is perfectly aligned; (ii) the impact of interference leakages. For both cases, closed-form expressions of outage probability and ergodic capacity are derived. The results, which are validated by Monte Carlo simulations, show that interference leakages can deteriorate both system performance and the diversity gains considerably.

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