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In this paper we consider distributed cognitive radio networks (CRNs) with channel aggregation (CA) scheme where there are multiple wireless channels and multiple secondary users (SUs). SUs in CRNs with CA can transmit bits of data through more than one idle channels which are not used by primary users (PUs). SUs decide whether to access idle channels or not based on the access probability (AP), and...
In cognitive radio (CR) networks, there is a common assumption that the secondary devices always obey the spectrum access rules and are under full control. However, this may become unrealistic for future CR networks composed of intelligent, complicated and autonomous devices. To solve this problem, the concept of “proactive-optimization” cognitive radio (POCR) is proposed in this paper, in which the...
This paper investigates an optimal mode selection policy for cognitive radio sensor networks powered by RF energy harvesting. The RF energy harvesting enables the sensor node to operate with a potentially perpetual lifetime. We assume that the sensor node harvests RF energy received from the primary network and it cannot carry out RF energy harvesting and opportunistic spectrum access at the same...
Inefficient spectrum usage is a crucial issue in wireless communications and methods for dynamic spectrum access are proposed based on spectrum sensing methodology of the cognitive radio systems. Beside the detection and estimation methods, spectrum sensing procedures can also benefit from the modeling and prediction of the wireless spectrum usage. Markovian, regressive and other approaches are introduced...
This paper considers a cognitive radio network where the cognitive user has a constant bandwidth which is K times that of a primary user. The primary system consists of constant primary channels and the cognitive system consists of channels, where is the largest integer not greater than x. The effects of imperfect spectrum sensing (with...
In this paper, we consider the shared used model in the context of IEEE 802.22 cognitive and investigate spectrum trading via auction approach. We consider two different scenarios in which the dominant risk is either associated with imperfect spectrum sensing or the uncertainties in the environment. Taking into account these risks, we propose a bidding strategy for sealed-bid first-price auction....
We investigate the channel assignment problem in a cluster-based multi-channel cognitive radio sensor network in this paper. Due to the inherent power and resource constraints of sensor networks, energy efficiency is the primary concern for network design. An R-coefficient is developed to estimate the predicted residual energy using sensor information (current residual energy and expected energy consumption)...
This paper looks into the modeling of information transmission over cognitive interrogator-sensor networks (CISNs), which represent an import class of sensor networks deployed for surveillance, tracking, and imaging applications. The crux of the problem is to develop a channel model that allows for evaluation of the sensing channel capacity and error rate performance, where the sensing link is overlaid...
An analytical formulation of the mean detection time and the distribution of the detection time of a wireless microphone (primary user) in an IEEE 802.22 wireless regional area network (WRAN) is presented. The IEEE 802.22 WRAN has a number of customer-premises equipments (CPEs) in the coverage area of its base station. Out of this number of CPEs, a number of them are within the coverage area of the...
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