scholarly journals Improved Buffer-Aided Multi-Hop Relaying with Reduced Outage and Packet Delay in Cognitive Radio Networks

Electronics ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 895
Author(s):  
Shakeel Alvi ◽  
Riaz Hussain ◽  
Qadeer Hasan ◽  
Shahzad Malik
Keyword(s):  
Cognitive Radio ◽  
Outage Probability ◽  
Cognitive Radio Networks ◽  
Communication Systems ◽  
Performance Metrics ◽  
Packet Delay ◽  
Radio Spectrum ◽  
Radio Networks ◽  
Cooperative Relaying ◽  
End To End

Cognitive radio networks have emerged to exploit optimally the scarcely-available radio spectrum resources to enable evolving 5G wireless communication systems. These networks tend to cater to the ever-increasing demands of higher data rates, lower latencies and ubiquitous coverage. By using the buffer-aided cooperative relaying, a cognitive radio network can enhance both the spectral efficiency and the range of the network; although, this could incur additional end-to-end delays. To mitigate this possible limitation of the buffer-aided relaying in the underlay cognitive network, a virtual duplex multi-hop scheme, referred as buffer-aided multi-hop relaying, is proposed, which improves throughput and reduces end-to-end delays while keeping the outage probability to a minimum as well. This scheme simultaneously takes into account the inter-relay interference and the interference to the primary network. The proposed scheme is modeled as a Markov chain, and Monte Carlo simulations under various scenarios are conducted to evaluate several key performance metrics such as throughput, outage probability, and average packet delay. The results show that the proposed scheme outperforms many non-buffer-aided relaying schemes in terms of outage performance. When compared with other buffer-aided relaying schemes such as max-max, max-link, and buffer-aided relay selection with reduced packet delay, the proposed scheme demonstrated better interference mitigation without compromising the delay performance as well.

MAC Layer Spectrum Sensing in Cognitive Radio Networks

2013 ◽  
pp. 210-230
Author(s):  
Mohamed Hamid ◽  
Abbas Mohammed
Keyword(s):  
Cognitive Radio ◽  
Cognitive Radio Networks ◽  
Performance Metrics ◽  
Computational Cost ◽  
Radio Spectrum ◽  
Radio Networks ◽  
Superior Performance ◽  
Mac Layer ◽  
Spectrum Utilization ◽  
Network Nodes

Efficient use of the available licensed radio spectrum is becoming increasingly difficult as the demand and usage of the radio spectrum increases. This usage of the spectrum is not uniform within the licensed band but concentrated in certain frequencies of the spectrum while other parts of the spectrum are inefficiently utilized. In cognitive radio environments, the primary users are allocated licensed frequency bands while secondary cognitive users can dynamically allocate the empty frequencies within the licensed frequency band, according to their requested quality of service specifications. In this chapter, the authors investigate and assess the performance of MAC layer sensing schemes in cognitive radio networks. Two performance metrics are used to assess the performance of the sensing schemes: the available spectrum utilization and the idle channel search delay for reactive and proactive sensing schemes. In proactive sensing, the adapted and non-adapted sensing period schemes are also assessed. Simulation results show that proactive sensing with adapted periods provides superior performance at the expense of higher computational cost performed by network nodes.

Role of Artificial Intelligence in Cognitive Radio Networks

2019 ◽  
pp. 258-279 ◽  
Author(s):  
Shikha Singhal ◽  
Shashank Gupta ◽  
Adwitiya Sinha
Keyword(s):  
Artificial Intelligence ◽  
Cognitive Radio ◽  
Cognitive Radio Networks ◽  
Evolutionary Process ◽  
Radio Spectrum ◽  
Radio Networks ◽  
Training Dataset ◽  
Wireless Medium ◽  
Computing Machines

The role of artificial intelligence techniques and its impact in context of cognitive radio networks has become immeasurable. Artificial intelligence redefines and empowers the decision making and logical capability of computing machines through the evolutionary process of leaning, adapting, and upgrading its knowledge bank accordingly. Significant functionalities of artificial intelligence include sensing, collaborating, learning, evolving, training, dataset, and performing tasks. Cognitive radio enables learning and evolving through contextual data perceived from its immediate surrounding. Cognitive science aims at acquiring knowledge by observing and recording externalities of environment. It allows self-programming and self-learning with added intelligence and enhanced communicational capabilities over wireless medium. Equipped with cognitive technology, the vision of artificial intelligence gets broadened towards optimizing usage of radio spectrum by accessing spectrum availability, thereby reducing channel interferences while communication among licensed and non-licensed users.

Game Theoretic Study of Cooperative Spectrum Leasing in Cognitive Radio Networks

2014 ◽  
Vol 5 (2) ◽  
pp. 61-74 ◽  
Author(s):  
Fatemeh Afghah ◽  
Abolfazl Razi
Keyword(s):  
Cognitive Radio ◽  
Cognitive Radio Networks ◽  
Stackelberg Game ◽  
Cooperative Behavior ◽  
Search Space ◽  
Radio Networks ◽  
Cooperative Relaying ◽  
Stackelberg Games ◽  
Secondary Users ◽  
Spectrum Leasing

In this paper, a novel property-right spectrum leasing solution based on Stackelberg game is proposed for Cognitive Radio Networks (CRN), where part of the secondary users present probabilistic dishonest behavior. In this model, the Primary User (PU) as the spectrum owner allows the Secondary User (SU) to access the shared spectrum for a fraction of time in exchange for providing cooperative relaying service by the SU. A reputation based mechanism is proposed that enables the PU to monitor the cooperative behavior of the SUs and restrict its search space at each time slot to the secondary users that do not present dishonest behavior in the proceeding time slots. The proposed reputation-based solution outperforms the classical Stackelberg games from both primary and reliable secondary users' perspectives. This novel method of filtering out unreliable users increases the PU's expected utility over consecutive time slots and also encourages the SUs to follow the game rule.

scholarly journals Efficient Channel Selection and Routing Algorithm for Multihop, Multichannel Cognitive Radio Networks with Energy Harvesting under Jamming Attacks

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Pham-Duy Thanh ◽  
Hiep Vu-Van ◽  
Insoo Koo
Keyword(s):  
Cognitive Radio ◽  
Energy Harvesting ◽  
Cognitive Radio Networks ◽  
Time Slot ◽  
Radio Networks ◽  
Switching Behavior ◽  
Jamming Attacks ◽  
Battery Capacity ◽  
Energy Constrained ◽  
End To End

We study jamming attacks in the physical layer of multihop cognitive radio networks (MHCRNs) where energy-constrained relays forward information from the source to the destination. Meanwhile, a jammer can transmit interfering signals on a channel such that all ongoing transmissions on this channel will be corrupted. In this paper, all jammers can attack only one of the predefined channels in each time slot. Moreover, they can randomly switch channels to start jamming another channel at the beginning of every time slot. The switching behavior is assumed to follow a Gaussian distribution. Due to limited battery capacity in the relays, energy harvesting is utilized to solve the energy-constrained problem in the cognitive radio network. Subsequently, relays are able to harvest energy from non-radio frequency (non-RF) signals such as solar, wind, or temperature. In this paper, we determine the throughput/delay ratio as a key metric to evaluate the performance in MHCRNs. Owing to the limited battery capacity in the relays and the jamming problem, the source needs to select proper relays and channels for each data transmission frame to optimize overall network performance in terms of end-to-end delay, throughput, and energy efficiency. Therefore, we provide two novel multihop allocation schemes to maximize achievable end-to-end throughput while minimizing delay in the presence of jammers. Through simulation results, we validate the effectiveness of the proposed schemes under multiple jamming attacks in MHCRNs.

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