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With the growing demand for wireless applications, there is an incalculable rise in bandwidth consumption that in turn leads to the spectrum scarcity. The conflict between spectrum underutilization and spectrum scarcity is solved by a well-known technology called Cognitive Radio (CR). The main aim of CR is to exploit unutilized spectrum of licensed users/Primary Users (PUs) and enable opportunistic...
In this paper, we propose a cognitive protocol that involves cooperation between the primary and secondary users. In addition to its own queue, the secondary user (SU) has a queue to store, and then relay, the undelivered primary packets. When the primary queue is nonempty, the SU remains idle and attempts to decode the primary packet. When the primary queue is empty, the SU splits the total channel...
In this paper we consider a cognitive radio network with access to N licensed primary frequency bands and their usage statistics, where the decentralized secondary users are subject to certain inter-network interference constraint. In particular, to limit the interference to the primary network, secondary users are equipped with spectrum sensors and are capable of sensing and accessing a limited number...
A single cognitive radio transmitter-receiver pair shares the spectrum with two primary users communicating with their respective receivers. Each primary user has a local traffic queue, whereas the cognitive user has three queues; one storing its own traffic while the other two are relaying queues used to store primary relayed packets admitted from the two primary users. A new cooperative cognitive...
Spectrum sensing in cognitive femtocells play an important role in detecting spectrum holes and to opportunistically use under-utilized frequency bands without causing harmful interference to macrocell users. In case of mass deployment of femtocells, interference management is essential to maximize the capacity and achievable data rates. In this paper, a novel algorithm is proposed, based on Lagrangian...
Unlike conventional radios, cognitive radios are to use channel occupancy information measured at the PHY layer and conveyed to the MAC layer to select suitable frequency bands to communicate. Many existing PHY/MAC decision-making strategies, however, assume that the cognitive radio belongs to a particular radio network and its communication capabilities are limited to the protocols supported by that...
In this paper, we focus on the network lifetime maximization in multiband cognitive radio systems. To deal with this problem, we formulate the optimization problem of an adaptive subchannel allocation and find an optimal solution. To reduce the computational complexity of the optimal solution, we also propose a heuristic algorithm. We use intensive simulations to verify the effectiveness of the proposed...
The prime focus of this work is in developing a protocol for a symbiotic architecture called Cognitive Relaying with Time Incentive for Multiple Primary Users (CRTI-M). The rationale of CRTI-M is that the Primary Users (PUs) of a Cognitive Radio (CR) network, with weak transmission links, seek cooperation from the cognitive Secondary User (SU) nodes in their vicinity, and in return reward them with...
Cognitive radio is an exciting emerging technology that has the potential of dealing with the urgent requirement and scarcity of the radio spectrum. Although having multiple radio interfaces and available spectrum bands can generally increase the effective throughput, a problem arises as to what the best strategy to dynamically assign available bands to secondary users for maximizing throughput by...
In order to bear reliable end-to-end services transmission in insecure IP network, SCTP as the transport protocol of the next-generation Internet was proposed. The performance of SCTP has been improved in related literature; however, they optimized it based on a single or a few parameters, which is lack of a comprehensive consideration in correlation parameters. In consideration of real-time and the...
Recent studies show that spectrum sensing in cognitive radio exposes vulnerabilities to adversaries. An intelligent adversary can launch sensing disruption in the sensing duration, by putting spoofing signals in allowable bands to prevent secondary users from accessing. In the meantime, the adversary can also attack secondary users by traditional jamming, once they access the spectral bands and start...
Channel allocation is an important area of research in open spectrum networks which asserts a significant impact on the spectrum utilization and the fairness among users. This paper studies the optimization of channel allocation, considering multiple objectives. For each objective, a binary programming model is described. Then a new optimization objective called fairness constrained maximum throughput...
Spectrum assignment is an important research problem in cognitive radio networks. Different from the conventional spectrum assignment algorithms which are mainly designed for ad hoc networks, in this paper, a new spectrum assignment algorithm for infrastructure based cognitive radio networks is proposed. This algorithm aims at maximizing the average bandwidth per flow, and avoiding the spectrum waste...
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