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In this work, full frequency reuse based transmission scheme is proposed for the ground-air communication systems. In full frequency reuse based systems, the receivers are interference-limited, and in this work, interference forwarding with a half-duplex (HD) dynamic decode-and-forward (DDF) relay is proposed to mitigate the interference. The HD DDF relay forwards the interference towards the interference-limited...
The coming decade will see an unprecedented air traffic growth and the installation of more avionic systems onboard aircrafts, in response to new services, safety and reliability requirements. The latter has triggered the evolution of avionic architecture towards the next generation Integrated Modular Avionics (IMA), due to space constraints under the Federated architecture. Furthermore, newer avionic...
The demand for high data rate communication is continuously increasing. To address this, studies on bit error rate improvements, cooperative diversity and transmit diversity have been topics of interest. In this paper, a novel Quad State- Paired QPSK (QS-PQPSK) modulation scheme is proposed. The proposed technique is simulated and compared with other main PSK-based modulation schemes. Preliminary...
Two key tasks in the development of cognitive radio networks in commercial and military applications are spectrum sensing and automatic modulation classification (AMC). These tasks become even more difficult when the cognitive radio receiver has no information about the channel or the modulation type. An integrated scheme which includes both these aspects is proposed in this paper. Spectrum sensing...
Recent years have shown a growing interest in the concept of cognitive radios (CR), in order to access the electromagnetic spectrum in an opportunistic way. Such systems require efficient spectrum detectors able to work in low signal-tonoise ratio (SNR) environments, with little or no information about the signals. In this paper, using the theory of higher-order statistics (HOS), a two-stage spectrum...
Fixed threshold based conventional energy detection methods may not work well in low signal-to-noise (SNR) cognitive radio (CR) scenarios where the ability to detect a primary user or to avoid a false alarm has been found to be severely degraded. In this paper, we investigate the effect of low SNR on a static threshold based energy detector. We discuss the reasons for the degradation in performance...
Spectrum sensing techniques for Cognitive radios have led to the emergence of a wide variety of analytical methods to detect the presence of a primary user. Though each technique has its own advantages, the disadvantages associated with them makes a standalone implementation of the technique unviable for practical use. A two stage detector for spectrum sensing can be used to mitigate the disadvantages...
The initial deployment of wireless sensor networks focused more on applications which collected periodic information from places which are not easily accessible. As a result the Medium Access Control (MAC) protocols for Wireless Sensor Networks (WSN) focused more on minimizing per node energy consumption to extend the life span of sensor nodes. This lead to the design of sensor MAC protocols which...
Automatic modulation classification (AMC) finds various applications in cognitive radios. This paper presents a method for the automatic classification using cumulants derived using fractional lower order statistics. The performance of the classifier is presented in the form of probability of correct classification under noisy and fading conditions. Unlike many of the conventional methods, the proposed...
One of the key requirements in cognitive radio is accurate detection of vacant spectrum bands. In this paper, an energy detector based on a tree-structured quadrature mirror filter bank (TQMFB) is proposed for detecting the center frequencies of the channels (frequency bands). Simulation results are presented to show the trade off between the window size, k, and the error in estimating the center...
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