scholarly journals Efecto de la distribución del tiempo de servicio de los usuarios primarios en las estadísticas de los espacios en blanco de un sistema de radio cognoscitivo

2018 ◽  
pp. 15-23
Author(s):  
Genaro Hernández-Valdez ◽  
Felipe Alejandro Cruz-Pérez ◽  
José Omar Labastida-Cuadra ◽  
Grethell Georgina Pérez-Sanchez
Keyword(s):  
Cognitive Radio ◽  
Communication Networks ◽  
Service Time ◽  
Discrete Event ◽  
Traffic Load ◽  
Interarrival Time ◽  
Service Time Distribution ◽  
White Space ◽  
Secondary Users ◽  
White Spaces

Cognitive radio technology was developed for spectral efficiency improvement in mobile communication networks. This is achieved by allowing secondary users to opportunistically and transparently use the white spaces of the primary network. In this paper, the effect of the service time distribution of the primary users in the statistics of the white spaces is analyzed. In particular, the first two standardized moments of both, white space time and white space interarrival time are found, considering the following distributions for the primary service time: log-normal, Weibull, and Pareto. One of the most relevant results is that, for low (moderate or high) traffic load, the exponential (hiper-exponential) distribution is an excellent option for modelling the white space duration. Characterizing these variables allow us to use the on-off paradigm to capture the primary channel activity and, in this way, evaluate the performance of cognitive radio networks. Results were obtained by using discrete event simulation techniques.

scholarly journals A heavy-traffic theorem for the GI/G/1 queue with a Pareto-type service time distribution

1998 ◽  
Vol 11 (3) ◽  
pp. 247-254 ◽  
Author(s):  
J. W. Cohen
Keyword(s):  
Service Time ◽  
Time Distribution ◽  
Heavy Traffic ◽  
Asymptotic Series ◽  
Traffic Load ◽  
Interarrival Time ◽  
Service Time Distribution ◽  
Tail Probabilities ◽  
S Transform ◽  
Stationary Waiting Time

For the GI/G/1 queueing model with traffic load a<1, service time distribution B(t) and interarrival time distribution A(t), whenever for t→∞1−B(t)∼c(t/β)ν+O(e−δt),c>0,1<ν<2,δ>0, and ∫0∞tμdA(t)<∞ for μ>ν, (1−a)1ν−1w converges in distribution for a↑1. Here w is distributed as the stationary waiting time distribution. The L.-S. transform of the limiting distribution is derived and an asymptotic series for its tail probabilities is obtained. The theorem actually proved in the text concerns a slightly more general asymptotic behavior of 1−B(t), t→∞, than mentioned above.

scholarly journals Channel accessing and handoff mechanisms in TV white spaces based on channel sensing and database information

2018 ◽  
Vol 7 (4.20) ◽  
pp. 12
Author(s):  
Krishna Chaitanya K ◽  
Meghalatha CK ◽  
Annapurna K ◽  
Seetha Ramanjaneyulu B
Keyword(s):  
Cognitive Radio ◽  
Cognitive Radio Networks ◽  
Primary User ◽  
Radio Networks ◽  
Successful Implementation ◽  
Secondary Users ◽  
Tv White Spaces ◽  
Primary Users ◽  
White Spaces ◽  
Speed Up

Opportunistic channel accessing and handoff mechanisms are crucial for the successful implementation of cognitive radio networks that depend on vacant channel frequencies of TV white spaces and other primary users. In this work, two such mechanisms that enable quick accessing of vacant channels and cause less interference to primary users are proposed. In these methods, combination of database information and local sensing of channels is used, to know about available vacant channels. If the primary user of incumbent channel returns, the secondary user moves to another vacant channel that is found to be free after scanning. Information from database can be used to speed up the process by limiting the scanning to few probable channels, instead of searching for all. The results show that these methods offer quick handoff of secondary users and cause less interference to primary users.  

The MacLaurin series for the GI/G/1 queue

1992 ◽  
Vol 29 (1) ◽  
pp. 176-184 ◽  
Author(s):  
Wei-Bo Gong ◽  
Jian-Qiang Hu
Keyword(s):  
Service Time ◽  
Mean Value ◽  
Interarrival Time ◽  
Service Time Distribution ◽  
Maclaurin Series ◽  
Recursive Procedure ◽  
Derivatives Of ◽  
System Time ◽  
Time Density ◽  
Mean Value Formula

We derive the MacLaurin series for the moments of the system time and the delay with respect to the parameters in the service time or interarrival time distributions in the GI/G/1 queue. The coefficients in these series are expressed in terms of the derivatives of the interarrival time density function evaluated at zero and the moments of the service time distribution, which can be easily calculated through a simple recursive procedure. The light traffic derivatives can be obtained from these series. For the M/G/1 queue, we are able to recover the formulas for the moments of the system time and the delay, including the Pollaczek–Khinchin mean-value formula.

The MacLaurin series for the GI/G/1 queue

1992 ◽  
Vol 29 (01) ◽  
pp. 176-184 ◽  
Author(s):  
Wei-Bo Gong ◽  
Jian-Qiang Hu
Keyword(s):  
Service Time ◽  
Mean Value ◽  
Interarrival Time ◽  
Service Time Distribution ◽  
Maclaurin Series ◽  
Recursive Procedure ◽  
Derivatives Of ◽  
System Time ◽  
Time Density ◽  
Mean Value Formula

We derive the MacLaurin series for the moments of the system time and the delay with respect to the parameters in the service time or interarrival time distributions in the GI/G/1 queue. The coefficients in these series are expressed in terms of the derivatives of the interarrival time density function evaluated at zero and the moments of the service time distribution, which can be easily calculated through a simple recursive procedure. The light traffic derivatives can be obtained from these series. For the M/G/1 queue, we are able to recover the formulas for the moments of the system time and the delay, including the Pollaczek–Khinchin mean-value formula.

An Energy Efficient Spectrum Aware Routing for Cognitive Radio Networks (CRNs)

2020 ◽  
Vol 10 ◽  
Author(s):  
Dileep Reddy Bolla ◽  
Jijesh J J ◽  
Mahaveer Penna ◽  
Shiva Shankar
Keyword(s):  
Cognitive Radio ◽  
Spectrum Sensing ◽  
Cognitive Radio Networks ◽  
Energy Efficient ◽  
Research Work ◽  
Spectrum Management ◽  
Residual Energy ◽  
Radio Networks ◽  
Traffic Load ◽  
The Impact

Back Ground/ Aims:: Now-a-days in the Wireless Communications some of the spectrum bands are underutilized or unutilized; the spectrum can be utilized properly by using the Cognitive Radio Techniques using the Spectrum Sensing mechanisms. Objectives:: The prime objective of the research work carried out is to achieve the energy efficiency and to use the spectrum effectively by using the spectrum management concept and achieve better throughput, end to end delay etc., Methods:: The detection of the spectrum hole plays a vital role in the routing of Cognitive Radio Networks (CRNs). While detecting the spectrum holes and the routing, sensing is impacted by the hidden node issues and exposed node issues. The impact of sensing is improved by incorporating the Cooperative Spectrum Sensing (CSS) techniques. Along with these issues the spectrum resources changes time to time in the routing. Results:: All the issues are addressed with An Energy Efficient Spectrum aware Routing (EESR) protocol which improves the timeslot and the routing schemes. The overall network life time is improved with the aid of residual energy concepts and the overall network performance is improved. Conclusion:: The proposed protocol (EESR) is an integrated system with spectrum management and the routing is successfully established to communication in the network and further traffic load is observed to be balanced in the protocol based on the residual energy in a node and further it improves the Network Lifetime of the Overall Network and the Individual CR user, along with this the performance of the proposed protocol outperforms the conventional state of art routing protocols.

scholarly journals An SETM Algorithm for Combating SSDF Attack in Cognitive Radio Networks

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
S. Tephillah ◽  
J. Martin Leo Manickam
Keyword(s):  
Cognitive Radio ◽  
Spectrum Sensing ◽  
Trust Management ◽  
Cooperative Spectrum Sensing ◽  
Radio Networks ◽  
Second Phase ◽  
Common Channel ◽  
Secondary Users ◽  
Management Algorithm ◽  
Different Types

Security is a pending challenge in cooperative spectrum sensing (CSS) as it employs a common channel and a controller. Spectrum sensing data falsification (SSDF) attacks are challenging as different types of attackers use them. To address this issue, the sifting and evaluation trust management algorithm (SETM) is proposed. The necessity of computing the trust for all the secondary users (SUs) is eliminated based on the use of the first phase of the algorithm. The second phase is executed to differentiate the random attacker and the genuine SUs. This reduces the computation and overhead costs. Simulations and complexity analyses have been performed to prove the efficiency and appropriateness of the proposed algorithm for combating SSDF attacks.

scholarly journals Multi-Winner Spectrum Allocation in Cognitive Radio Networks: A Single-Sided Auction Theoretic Modelling Approach with Sequential Bidding

Electronics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 602
Author(s):  
Monisha Devi ◽  
Nityananda Sarma ◽  
Sanjib K. Deka
Keyword(s):  
Cognitive Radio ◽  
Communication Networks ◽  
Spectrum Sharing ◽  
Single Channel ◽  
Group Formation ◽  
Radio Spectrum ◽  
Spectrum Allocation ◽  
Allocation Mechanism ◽  
Sealed Bid ◽  
Sequential Bidding

Cognitive radio (CR) has evolved as a novel technology for overcoming the spectrum-scarcity problem in wireless communication networks. With its opportunistic behaviour for improving the spectrum-usage efficiency, CR enables the desired secondary users (SUs) to dynamically utilize the idle spectrum owned by primary users. On sensing the spectrum to identify the idle frequency bands, proper spectrum-allocation mechanisms need to be designed to provide an effectual use of the radio resource. In this paper, we propose a single-sided sealed-bid sequential-bidding-based auction framework that extends the channel-reuse property in a spectrum-allocation mechanism to efficiently redistribute the unused channels. Existing auction designs primarily aim at maximizing the auctioneer’s revenue, due to which certain CR constraints remain excluded in their models. We address two such constraints, viz. the dynamics in spectrum opportunities and varying availability time of vacant channels, and formulate an allocation problem that maximizes the utilization of the radio spectrum. The auctioneer strategises winner determination based on bids collected from SUs and sequentially leases the unused channels, while restricting the channel assignment to a single-channel-multi-user allocation. To model the spectrum-sharing mechanism, we initially developed a group-formation algorithm that enables the members of a group to access a common channel. Furthermore, the spectrum-allocation and pricing algorithms are operated under constrained circumstances, which guarantees truthfulness in the model. An analysis of the simulation results and comparison with existing auction models revealed the effectiveness of the proposed approach in assigning the unexploited spectrum.

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