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This paper presents a method of optimizing sensor node coordination in order to reassign the nodes in linear array arrangement to form a linear antenna array. This linear sensor node array (LSNA) is constructed within random sensor node deployment. The LSNA should be optimized as closely comparable as a conventional uniform linear array (ULA) to minimize the beamforming performance errors. Beamforming...
Motivated by the inefficient usage of the licensed spectrum across many frequency bands, cognitive radio (CR) was proposed to promote the spectrum utilization by opportunistically exploiting the existence of spectrum ??holes.?? Under this new paradigm, cognitive (unlicensed) user is allowed unobtrusive access to a channel exhibiting negligible primary (licensed) user activity. Cooperative communication...
Cognitive radio wireless networks are an emerging communication paradigm to effectively address spectrum scarcity challenge. Spectrum sensing plays a paramount role in cognitive radio, which is widely agreed to be the most promising method for alleviating the symptom of RF spectral scarcity. Dynamic access of unused spectrum via a cognitive radio asks for flexible radio circuits that can work at an...
A Software Defined Radio (SDR) is a radio which can tune to any frequency band, transmit and receive different modulations and different physical parameters across a large frequency spectrum by using a programmable hardware and powerful software. An SDR performs significant amounts of signal processing in a general purpose computer, or a reconfigurable piece of digital electronics or the combination...
The 2.4 GHz industrial, science and medical (ISM) band is a license free band allocated for a variety of consumer applications: environmental monitoring, agriculture, medical care, smart buildings, factory monitoring and automation, and numerous military applications. This project focuses on the adaptive interference avoidance scheme for IEEE 802.15.4 to allow coexistence with IEEE 802.11b/g in the...
Limited available spectrum and the inefficiency in the spectrum usage necessitate the use of cognitive radio (CR) approach to exploit the existing wireless spectrum opportunistically. To achieve the goal of CR, it is a fundamental requirement that the cognitive user (CU) performs spectrum sensing to detect the presence of the primary user (PU) signal before a spectrum is accessed to avoid interference...
This paper presents a method which intelligently determines the optimum node coordination of sensor nodes topology. The topology is in linear array, aimed for beamforming in wireless sensor networks (WSNs). The array is constructed in random sensor node deployment. The selected nodes should align similar to a uniform linear array (ULA) to minimize the position errors which will improve the beamforming...
Cognitive radio has the ability to sense the environment and adapt its behavior to optimize communication features, such as quality of service in the presence of interference and noise. In physical layer to achieve this goal, different phases of sensing, channel estimation, and configuration selection are necessary. The sensing part measures the interference level, recognize the spectrum holes, and...
Orthogonal frequency division multiplexing (OFDM) is proven a successful technique in wireless communication system which is sensitive to carrier frequency offset (CFO). The effect of CFO introduces intercarrier interference (ICI) to OFDM system. The purpose of this paper is to reduce ICI using ICI self-cancellation in MIMO-OFDM system by data allocation in space-time-frequency (STF). This paper also...
The advanced developments in sensors and wireless communications devices have enabled the design of miniature, cost-effective, and smart physiological sensor nodes. One of the approaches in developing wearable health monitoring systems is the emerging of wireless body area network (WBAN). IEEE 802.15.4 provides low power, low data rate wireless standard in relation to medical sensor body area networks...
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