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The Cognitive Radio (CR) is an emerging technology for modern wireless communication system that offers a great solution to scarcity of radio spectrum. The Cognitive Radio Network (CRN) is an intelligent wireless communication organization that is aware of its environment. Here, heterogeneous nodes meet spectrum sensing challenges due to the variation of transmission power, spectrum allocation and...
We propose a compressive radar that uses single bit quantization of the received noisy signal. The one-bit quantization is performed by a comparator with a time-varying reference level. The problem is studied through a sparse method, leading to an optimization problem which can be solved numerically. Simulation results show that the proposed method has a promising performance.
This paper presents new system-level design for the cognitive sensor based on energy detection to boast the performance accuracy by maintaining a queue of energy samples and computing their average to determine the decision threshold. Thereafter, these values summed over average number of samples are again compared with the recent energy value to decide whether the spectrum is occupied or unoccupied...
Electric power systems are among most spatially extended engineered systems. Their stable operation in the presence of disturbances and outages is made possible by real-time control over communication networks. Communication delay is one of the unavoidable side-effects of using a computer network to interconnect sensors, actuators and control centers/nodes. We propose here a delay canceling approach...
In this paper, a continuous-time differential type multi-signal parallel driving architecture touch screen sensing circuit for projective capacitive type panel is presented. In order to further enhance the Signal-to-Noise Ratio (SNR), a new transmitter (TX) architecture is proposed with parallel signal processing algorithm. In this work, charge amplifiers with built-in band-pass filter are designed...
In this paper, off-body channel measurements are proposed using miniaturized chip antennas (dimension: 7 × 2 × 1.20 mm3) under pattern diversity configuration at 2.2–2.3 GHz. The measurements were carried out in a multipath indoor laboratory environment using two sensors as transmitter and receiver deployed on-body and free-space, respectively where each sensor comprises two miniature chip antennas...
The number of applications that use industrial, scientific and medical (ISM) radio bands increase every day, creating interference problem for the wireless sensor networks (WSN) that generally operate on these bands. Cognitive radio sensor network (CRSN) has been proposed as a promising solution to this problem. However, since sensor nodes are energy-constrained devices energy efficient spectrum sensing...
In this paper we investigate the reason on how the side peaks of ambiguity function are generated, and propose the solution to eliminate the side peaks, the occurrence of side-peak may mask the faint targets echoes at low signal-to-noise ratio (SNR), rendering target localization difficult. By developing cyclostationarity of pilots, we prove that the side peaks care caused by the periodicity of pilots...
We consider the scenario in which multiple sensors send spatially correlated data to the fusion center (FC) via independent Rayleigh-fading channels with additive noise. Assuming that the sensor data is sparse in some basis, we show that the recovery of the signal can be formulated as a compressive sensing (CS) problem. To model the scenario where sensors operate with intermittently available energy...
Spectrum sensing is one of the most important components of cognitive radio (CR) technology. In this paper, we investigate the design of the sensing time to minimize the secondary user (SU) transmission delay under the condition of sufficient protection to primary users (PUs). It has been proven that there exists one optimal sensing time which yields the minimum transmission delay. Then, a novel cooperative...
Time delay estimation (TDE) is an important problem in many fields of the engineering. The work is looking from the sonar based applications point of view, where the time difference between transmitted pulse and received echo is important for target and object detection and recognition. From many available well know methods, only three time domain methods were considered and investigated: Direct Correlation...
We consider a simple ad-hoc cognitive scenario with two data up-links, one licensed to use the spectral resource (primary) and the other unlicensed (secondary or cognitive). It is assumed that the cognitive link accesses the channel only when the channel is sensed idle. An ON-OFF channel model is used for the primary link, where traffic statistical characteristics are taken into account. A closed-form...
This paper investigates time-delay estimation for acoustic source localization in a distributed microphone array. The microphones are assumed to be part of a wireless sensor network, with a constraint on the number of bits that may be exchanged between the sensors. Consequently, at the fusion center, time-delay estimation needs to be performed using quantized signals. In this paper, the relation between...
We consider the problem of robustly detecting the presence/absence of signals in low signal to noise ratio (SNR) environments. Our previous results have shown the existence of thresholds called SNR walls, below which robust detection becomes impossible due to uncertainties in the environment. These thresholds were shown to exist for many signals used in practice. This paper introduces the idea of...
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