scholarly journals MAC Protocol for Quality-Aware Real-Time Voice Delivery in Cognitive Radio-Enabled WSNs

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Bosung Kim ◽  
Gyu-min Lee ◽  
Byeong-hee Roh

We propose a quality-aware media access control (MAC) protocol for real-time voice delivery in cognitive radio- (CR-) enabled wireless sensor networks (WSNs). The temporal structure of the system model is addressed by using periodic timeslots in order to make more efficient use of the spectrum. In our proposed temporal structure, a bandwidth broker in such centralized CR networks (CCRNs) is selected as a central counterpart to synchronize with secondary users (SUs) and assign spectral resources to them. We develop an analytical model for SUs for the Call Admission Control (CAC) of voice traffic using the quality of service (QoS) requirements of delay bound and delay bound violation probability. Ours is an approach that provides reliable data transmission and reduces packet delay and packet delay jitter. In addition to the aforementioned packet-level performance metrics, we calculated a call-level performance metric, that is, the number of acceptable SUs, satisfying QoS requirements.

2018 ◽  
Vol 7 (2.20) ◽  
pp. 335
Author(s):  
Shweta Alpna ◽  
Amrit Mukherjee ◽  
Amlan Datta

The proposed work illustrates a novel technique for cooperative spectrum sensing in a cognitive radio (CR) network. The work includes an approach of identifying secondary users (SUs) based on Hierarchical Maximum Likelihood (HML) technique followed by Vector Quantization. Initially, the arrangement of the SUs are been observed using HML with respect to a spatial domain and then the active SUs among them are identified using VQ. The approach will not only save the energy, but the decision of the real-time and dynamic cooperative communication network becomes more accurate as we can predict the behavior of SUs movement and spectrum sensing by each individual SU at that particular  place. The results and simulations of the real-time experiment justifies with the proposed approach. 


Author(s):  
Pablo Gutierrez Peon ◽  
Pedro Manuel Rodriguez ◽  
Zaloa Fernandez ◽  
Francisco Pozo ◽  
Elisabeth Uhlemann ◽  
...  

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2088
Author(s):  
Kalpana Devarajan ◽  
Muthukrishnan Senthilkumar

This article studies the strategic access of single-server retrial queue with two types of customers, where priority is given according to their category. On the basis of this concept, a cognitive-radio network was developed as retrial queue with energy harvesting. Cognitive radio allows for a secondary user to opportunistically access the idle spectrum of a primary user (PU). Upon arrival of a primary user, the service given to the secondary user by the cognitive radio is interrupted, and the PU band is available for the primary user. After completion of service for the primary user, the PU band is again available to secondary users. Performance metrics are derived to study the equilibrium strategies of secondary users. A Stackelberg game was formulated and Nash equilibrium was derived for the noncooperative strategy of the secondary user. Game-theory concepts are incorporated with queuing theory ideas to obtain the net benefit for the noncooperative strategy and social benefit for cooperative strategy. Lastly, analytical results are verified with numerical examples, and the effects of energy-harvesting rate are discussed.


2021 ◽  
Vol 36 (1) ◽  
pp. 73-79
Author(s):  
Mahmoud Ali Ammar

In Cognitive Radio Networks (CRN), the main aim is to allow the secondary users (SUs) to identify the empty bands and use them to transmit or receive data opportunistically. Primary users (PUs) have the priority to use a channel, while the secondary users must vacant this channel once a primary user requests it. An attack known in cognitive radio networks as a Primary User Emulation Attack (PUEA) aims to prevent the SU from using the empty bands. In this paper, an analytical and experimental approach is presented to mitigate the PUEA. This approach is based on obtaining the Probability Density Functions (PDFs) of the received powers at the secondary users from malicious nodes and also from the primary transmitter in the cognitive network. Then, these obtained PDFs are used in Neyman-Pearson composite hypothesis test to measure the performance metrics (probability of false alarm and miss detection in the network). The results proved that the performance metrics were greatly influenced by the network area, where the secondary user is located, and the threshold value λ used in the decision rule. Also, there are boundaries for the λ choices that cannot be overtaken.


Electronics ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 895
Author(s):  
Shakeel Alvi ◽  
Riaz Hussain ◽  
Qadeer Hasan ◽  
Shahzad Malik

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.


Sign in / Sign up

Export Citation Format

Share Document