Theses and Dissertations
Permanent URI for this collectionhttp://ir.daiict.ac.in/handle/123456789/1
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Item Open Access Design of digital accelerometer based seismic sensor node(Dhirubhai Ambani Institute of Information and Communication Technology, 2010) Sharma, Nisha; Ranjan, PrabhatThe aim of Design of Digital Accelerometer based Seismic Sensor Node is to propose a design for wireless sensor network for exploring the sub-surface region of the moon by studying the seismic waves generated over there. As Moonquakes are less frequent and are smaller in scale than are earthquakes, we need a sensor network of high sensitivity that can live up to a longer period of time over which we can take necessary readings to study the sub-surface region of moon. In the system proposed, four seismic sensor nodes are considered which need to be arranged in linear fashion over the surface of the moon with the help of rover. These nodes would collect data of the passive seismic events that takes place on the moon and transmit it to the base station so that the information could be used by the Researchers/ Seismological officials for further studies. The components of the sensor node include an accelerometer, Analog to Digital converter. A microcontroller would collect data from sensor and store it on data flash. The power requirements of the sensor node would be met by a battery. The base station of the system would be on rover and would be able to collect data through direct transmission from all the four nodes. The system thus developed would be able to collect the seismic events over a life time of approx. 6months. The thesis discusses the hardware design and issues faced during the design with their solution. The prime emphasis of the design is on the miniaturization in the size, low weight and lower power consumption of the node.Item Open Access Bidding strategies for dynamic spectrum allocation(Dhirubhai Ambani Institute of Information and Communication Technology, 2010) Dhumal, Neha; Srivastava, SanjayDynamic Spectrum Allocation is the process of assigning spectrum licenses in terms of the chunks of the spectrum band to the Wireless Service Providers (WSPs). This allocation assignment is being done as per the WSPs' requirement and this in turn would depend on the end users' applications demand [16]. For Dynamic Spectrum Access, economic framework is needed to make the system feasible under economic terms. This process uses some kind of service pricing mechanism that the service provider can use for the acquisition of the spectrum band and requirement of the end users.In the Dynamic Spectrum Allocation scenario, the problem is to find the appropriate bidding strategies. The approach to this problem is to simulate the different cases with varying parameters. Here, the interaction between the spectrum owner and providers is modeled through auction model which has been studied in this work whereas the interaction between the providers and end users is based on the demand. This thesis presents the bidding strategies and appropriate prediction method that maximize the revenue and the profit of both the providers as well as the end users. The auction method and different bidding strategies adopted, gives the winning criteria for the providers on how many number of units to bid and the prices for these units. Prediction method for the price uses the concept of probability of winning the particular unit. Simulation results show the comparison between prediction and actual values, revenue and profits of the providers. Among the different auction and bidding methods, the Vickrey auction has been used in this work. In the Vickrey auction method, the allocation of the resources is done efficiently as compared to other methods and does provide dominant bidding strategy.
Item Open Access Investigation on multi-band fractal antennas for satellite applications(Dhirubhai Ambani Institute of Information and Communication Technology, 2010) Shah, Milind; Gupta, SanjeevRemote sensing is a very important application of satellite communication. In remote sensing applications, multiple frequencies are utilized. Use of different antennas for different frequencies is a complex task and so use of single multiband antenna is desirable. Fractal geometries can be utilized to design single multiband antenna operating at various required frequencies which may be widely separated and non-harmonically related. In this thesis fractal geometry concept has been utilized to achieve multiband and compact design. Here multifractal cantor geometry is used due to its simple construction and ease in tuning. In addition to multiband behavior, the antenna must provide sufficient bandwidth. Unfortunately the microstrip antennas are having very narrow bandwidth. There are other techniques to increase bandwidth such as aperture coupled structure or electromagnetically coupled structure. But these solutions result in the complex multilayer structure. To prevent this complexity and to increase bandwidth, monopole structure has been utilized. Usually for satellite communication 28 dB to 32 dB gain is required. To fulfill this requirement, an array using multiband element is also designed.Item Open Access Radiation analysis of microstrip active (amplifier) and passive (antenna) structures(Dhirubhai Ambani Institute of Information and Communication Technology, 2010) Dhoot, Vivek; Gupta, SanjeevAnalysis of radiation from a microstrip amplifier and a newly proposed microstrip antenna is presented. Microstrip amplifier is analyzed replacing the MMIC structure by an equivalent S2P model and remaining portion being constructed with the original dimensions. A printed monopole antenna using multifractal technique is proposed. This antenna has multiband characteristics covering various wireless applications including WLAN 2.4 GHz and 5.8 GHz applicationsItem Open Access Dual-band microstrip antenna design(Dhirubhai Ambani Institute of Information and Communication Technology, 2005) Desai, Bhumi; Gupta, SanjeevMulti-frequency microstrip antennas are very much in demand due to their physical and mechanical properties like small size, lightweight, thin profile, low power consumption, and ease of implementation in the domestic applications. Some designs of dual-band microstrip patch suitable for GSM 900/1800 base station operation are already a research topic. Dual frequency microstrip antennas are also used in GPS and SAR. Commercially, these are deployed in RFID tags. But for the antenna to be useful in all these applications, its behavior like return loss, bandwidth, beam width, radiated power, gain, and directivity, at both the frequencies, should be nearly identical. The purpose of this work is to design the microstrip patch for dual frequencies of 945 MHz and 1960 MHz. Two new approaches called Coplanar patches and Overlapped patches are proposed. Then some of the existing techniques like Stacked patches, Dual slot loaded patches and Dual frequency PIFA are explored for our design specifications. Finally, the comparison of all the design aspects including the proposed ones is carried out in this work.Item Open Access Shorted microstrip patch antenna(Dhirubhai Ambani Institute of Information and Communication Technology, 2005) Bala, Shashi; Gupta, SanjeevIn this thesis, electrically small microstrip patches incorporating shorting posts are thoroughly investigated. These antennas are suitable for mobile communications handsets where limited antenna size is a premium. In particular, it is shown that the zero mode of the unloaded MSA (Microstrip Antenna) plays a central role for reducing the lowest operation frequency of the loaded MSA. The studies carried out allow the determination of all relevant antenna parameters for different post specifications and can easily be extended for different patch architectures.