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Cognitive radio (CR) is a critical issue to solve the spectrum scarcity and to improve frequency spectrum utilization in wireless communication. Spectrum sensing is the first step for cognitive radio and it needs to detect signals presence under strict requirement such that secondary users (unlicensed users) can use the licensed spectral band without interfering primary users (licensed users). In...
One of the key problems in cognitive radio (CR) is the detection of primary activity in order to determine which parts of the spectrum are available for opportunistic access. In this work, we present a new multiantenna detector which fully exploits the spatial and temporal structure of the signals. In particular, we derive the generalized likelihood ratio test (GLRT) for the problem of detecting a...
The energy based test is a popular detection scheme for cognitive radio (CR). However, it is infeasible or confronted with difficulty in threshold determination when a reference noise power level is unavailable or inaccurate. In fact, the presence of a primary signal not only changes the received signal energy, but also its correlation structure. In this paper, we show how to exploit information in...
In this paper, we introduce a spectrum holes detection approach, which combines blind modulation classification, angle of arrival estimation and number of sources detection. We perform eigenspace analysis to determine the number of sources, and estimate their angles of arrival. In addition, we classify detected sources as primary or secondary users with their distinct second-order/one-conjugate cyclostationarity...
In this paper, using tools from asymptotic random matrix theory, a new cooperative scheme for frequency band sensing is introduced for both AWGN and fading channels. Unlike previous works in the field, the new scheme does not require the knowledge of the noise statistics or its variance and is related to the behavior of the largest and smallest eigenvalue of random matrices. Remarkably, simulations...
In this paper, we propose a cognitive radio-based multi-user resource allocation framework for mobile ad hoc networks using multi-carrier DS CDMA modulation over a frequency-selective fading channel. In particular, given pre-existing communications in the spectrum where the system is operating, in addition to potential narrow-band interference, a channel sensing and estimation mechanism is provided...
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