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In this paper, cognitive machine to machine (CM2M) gateway in e-healthcare systems are presented by accessing several channels via periodic sensing and spectrum handoff. An optimal energy efficient spectrum management mechanism with multiple thresholds is proposed. The developed mechanism aims to reduce energy consumption in the system by optimizing the spectrum sensing and channel switching, while...
In this paper, a cooperative cognitive radio network (CRN) with energy harvesting capabilities of its secondary users is considered. Specifically, cooperative spectrum sensing and multi-antenna beamforming are employed to improve the sensing performance and the energy transfer efficiency, respectively. In our approach, a homogeneous CRN scenario is studied where the optimal sensing probability of...
Cooperative spectrum sensing has a great impact to increase the performance for detecting the Primary User (PU) signal over single node sensing. Recent developments in multiple antenna techniques adjoin a new dimension in spectrum sensing. In this paper, we have proposed a multi-antenna based signal detection for multi bands considering cooperative approach with Rayleigh fading channel. In addition...
In this paper, the throughput performance of a hybrid Multiple-Input-Multiple-Output (MIMO) interweave/underlay Cognitive Radio (CR) system is examined on an analytical basis. Specifically, hybrid CR systems that switch between an interweave and an underlay transmission strategy, based upon spectrum sensing measurements, are investigated. For the first time the performance of such a hybrid CR system...
We investigate a cognitive radio scenario involving a single cognitive transmitter equipped with antennas sharing the spectrum with primary users (PUs) transmitting over orthogonal bands. Each terminal has a queue to store its incoming traffic. We propose a novel protocol where the cognitive user transmits its packet over a channel formed by the aggregate of the inactive primary...
In this paper a switch-stay model is proposed for spectrum access by a secondary user in the presence of a primary user, which considers the impact of spectrum handoff delay. This model is then studied to balance the trade-off between the secondary user's energy efficiency and transmission reliability in light of the probability of collision, throughput and delay constraints. Bounds on the probability...
In this paper, we investigate the coexistence problem between the 802.22 and the 802.11af systems in the TV White Spaces (TVWS). We focus on the design of a co-channel coexistence scheme for the 802.22 customer-premises equipments (CPE) and the 802.11af systems. 802.22 and 802.11af are two typical standards envisioned to be widely adopted in the future. However, these two standards are heterogeneous...
We propose a spectrum-sensing and data-transmission scheme that utilizes multiple-input and multiple-output (MIMO) technology to enable the spectrum to be sensed and data to be transmitted simultaneously. By using our proposed scheme, the degradation of quality of service (QoS) that is caused by spectrum sensing can be reduced and the system throughput of a cognitive radio (CR) system can be increased,...
Multiple antennas have become a common component of wireless networks, improving range, throughput, and spatial reuse, both at the link and network levels. At the same time, carrier sensing is a widely used method of improving spatial reuse in distributed wireless networks, especially when there is limited coordination among non-communicating nodes. While the combination of carrier sensing and multiple...
Interference problems in cochannel femtocell networks may cause significant performance degradation for certain femtocell/macrocell users. These problems and potential solutions are recently being investigated within the 3GPP. The goal of the present paper is to review the simulation framework for femtocell networks in 3GPP and briefly summarize some of the important inter-cell interference coordination...
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