Department of Computer Science and Information Systems
Permanent URI for this collectionhttp://localhost:4000/handle/123456789/1928
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Item Narrowband and Wideband Directional Beamformer with Reduced Side Lobe Level(IEEE, 2019) Gudino, Lucy J.In this paper, the synthesis of narrow and wideband beamformers with reduced side lobe level and wide beam steering capability is presented. A closed form expression with slope equalization technique is derived for array factor of the beamformer to meet the desired beam-pattern specifications of Half Power Beam-Width (HPBW)and Side Lobe Level (SLL). The proposed beamformer design is adaptable to any bandwidth and null placement in the desired direction. The slope equalization method improves the SLL of the beamformer. Compared to Kaiser, Chebyshev, DPSS and Taylor beamformers, the proposed narrowband and wideband beamformers exhibit lower and tapered side lobes, hence improved First Null to Last Null (FNLN)ratio. The proposed wideband beamformer exhibits superior performance in the wideband frequency range of 1-3GHz.Item Hybrid area exploration–based mobility-assisted localization with sectored antenna in wireless sensor networks(Wiley, 2019-11) Gudino, Lucy J.In common practice, sensor nodes are randomly deployed in wireless sensor network (WSN); hence, location information of sensor node is crucial in WSN applications. Localization of sensor nodes performed using a fast area exploration mechanism facilitates precise location-based sensing and communication. In the proposed localization scheme, the mobile anchor (MA) nodes integrated with localization and directional antenna modules are employed to assist in localizing the static nodes. The use of directional antennas evades trilateration or multilateration techniques for localizing static nodes thereby resulting in lower communication and computational overhead. To facilitate faster area coverage, in this paper, we propose a hybrid of max-gain and cost-utility–based frontier (HMF) area exploration method for MA node's mobility. The simulations for the proposed HMF area exploration–based localization scheme are carried out in the Cooja simulator. The paper also proposes additional enhancements to the Cooja simulator to provide directional and sectored antenna support. This additional support allows the user with the flexibility to feed radiation pattern of any antenna obtained either from simulated data of the antenna design simulator, ie, high frequency structure simulator (HFSS) or measured data of the vector network analyzer (VNA). The simulation results show that the proposed localization scheme exhibits minimal delay, energy consumption, and communication overhead compared with other area exploration–based localization schemes. The proof of concept for the proposed localization scheme is implemented using Berkeley motes and customized MA nodes mounted with indigenously designed radio frequency (RF) switch feed network and sectored antenna.Item Improved Magnitude Weighting Technique for Wireless Sensor Network Beamformer(Helix, 2020-04) Gudino, Lucy J.The wireless sensor node consumes maximum energy for data communication which calls for highly directive beams for point to point communication applications to reduce its energy consumption in a Wireless Sensor Network (WSN). This paper presents the synthesis of a wideband beamformer, which is highly directive with reduced sidelobe level (SLL). It supports wide-angle beam steering which makes it suitable for Uniform Linear Array (ULA) WSN. An expression is obtained for weighting the array factor (AF) of the wideband beamformer to achieve beampattern model with desired SLL and Half Power Beam-Width (HPBW) specifications. Compared to Taylor and DPSS techniques, the proposed beamformer shows higher directivity for a given number of elements. It has lower and tapered sidelobes, hence better First Null to Last Null (FNLN) ratio. The proposed beamformer shows improved performance in wideband of interest i.e. 1-3GHz and basically, it is a non-optimization approach.