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In the wireless cellular network, location management is one of the intricate dynamic issues that expend the available limited wireless resources in order to guarantee for delivering a call to the mobile device. Towards enhancing the Quality of Service and reducing the dilemma of location management, an improved location update scheme has been proposed in this paper to capture the daily behavioral pattern of the mobile users. Here a profile based LU scheme has been developed according to the mobility pattern of the individual users in a cellular network. Especially, mobile phone data is recorded in a Call Data Record (CDR) data base containing the spatial–temporal information of the millions of anonymized users for consecutive 2 months. In this paper, the proposed profile based LU technique takes into consideration of the individual user movement to optimize the location update characteristics in order to minimize the signaling cost of mobile network. The proposed algorithm shows an improvement of 17% in terms of bandwidth compared to the conventional technique. The use of CDR data for profiling the users, the mathematical formulation which has not yet been used by the other researchers and validation of the algorithm based on actual user data rather than theoretically predicted data are the novelty of this work. [ABSTRACT FROM AUTHOR]

Aircraft/traffic alert and collision avoidance system (ACAS/TCAS) is an airborne system which is designed to provide the service as a last defense equipment for avoiding mid-air collisions between the aircraft. In the existing system, four monopole stub-elements are used as ACAS directional antenna and one blade type element is used as ACAS omnidirectional antenna. The existing ACAS antenna has some drawbacks such as low gain, large beamwidth, frequency and beam tuning/scanning issues etc. Antenna issues like unwanted signals reception may create difficulties to identify the possible threats. In this paper, the focus is on the design and development of a unit element microstrip antenna which can be used for ACAS application and to overcome the possible limitations associated with the existing techniques. Two proposed antenna models are presented here, which are single feed and dual feed microstrip dual patch slotted antenna. These are designed and simulated in CST Microwave Studio tool. The performance and other antenna characteristics have been explored from the simulation results followed by the antenna fabrication and measurement. A good reflection coefficient, Voltage Standing Wave Ratio (VSWR), narrow beamwidth, perfect directional radiation pattern, high gain and directivity make this proposed antenna a good candidate for this application. [ABSTRACT FROM AUTHOR]

A novel compact triband coplanar waveguide fed metamaterial antenna is proposed. The left-handed (LH) inductance is provided by two parallel short ended spiral inductors. We achieved pentamodes of resonance consisting of negative modes, zeroth mode and positive modes. The resonance frequency at each of these modes are f-2=1.01 GHz, f-1=2.11GHz, f0=2.48 GHz, f+1= 3.04 GHz and f+2=3.54GHz with triband functionality obtained at f-2, f0 and f+2 resonances. Gain of the proposed structure at f-2 f0 and f+2 resonances is found to be -3.4993dB, 1.559dB and 1.9515dB respectively. The proposed antenna is measured at Antenna Measurement Facility (AMF) and results were compared with the simulated results. A good agreement between the measured and the simulated results validates the proposed design. The antenna radiates omni-directional waves in the horizontal plane. The proposed antenna serves the criteria for modern multiband wireless applications with an additional feature of increased bandwidth at the zeroth mode. The proposed multiband antenna is suitable for wireless communication applications such as the Global System for Mobile Communications (GSM) 900 in 1.01GHz, Wireless Local Area Network (WLAN) in the 2.48 GHz band (2.459 - 2.4924)GHz of IEEE 802.1 lb/g ISM band and worldwide interoperability for microwave access (WiMax) standards in the 3.54GHz band (3.491-3.596)GHz of IEEE 802.11a. This proposed antenna is most suitable for precise multiband wireless communication systems which include the mobile and wireless local area network (WLAN) systems due to their large service area. [ABSTRACT FROM AUTHOR]