M Tech Dissertations
Permanent URI for this collectionhttp://drsr.daiict.ac.in/handle/123456789/3
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Item Open Access Generalized data extraction protocol for habitat monitoring applications in WSNs(Dhirubhai Ambani Institute of Information and Communication Technology, 2011) Hemnani, Deepak Manohar; Srivastava, SanjayHabitat monitoring applications use WSNs to gather data about environment and migration patterns of animals. This data is used by biologists to analyze the life and behavior of animals in different environments. The application involves designing of WSN nodes to tag the animals and running protocols to gather and exchange information to be collected at the base station. Given the limited resources i.e. energy and memory, there is a need for an energy efficient and memory efficient data extraction protocol. We take in to consideration previous work done in Zebra net and wild CENSE to formulate a generalized protocol which could be implemented as is. The protocol parameters are defined as symbols which are based on application parameters. My work involves identifying the gaps in the previous work done for habitat monitoring. Filling the gaps and coming up with a generalized protocol and finally providing formulation for the protocol in terms of application parameters.Item Open Access Design and layout of single bit per stage pipelined ADC(Dhirubhai Ambani Institute of Information and Communication Technology, 2011) Chaora, Ankeet; Sen, SubhajitThe concept of pipe-lining, often used in digital circuits, can also be applied in the analog domain. It helps to achieve higher speed where several operations must be performed serially. In this work, pipe-lining is employed to create the analog-to-digital converter. The architecture consists of N stages, each including a sample and hold circuit, an ADC, a DAC, a sub tractor and possibly an amplifier. In actual implementation we combine two or more of these functions in one circuit. By pipe-lining, in the converter an optimization can be obtained between maximum sampling clock and the speed of the circuits used. The layout of simulated pipe-lined ADC has been created and parasitic have been extracted. Rigorous pre-layout and post-layout simulations have been done and obtained results are analyzed. The single bit per stage pipe-lined ADC has been implemented in UMC 180nm technology and simulated in Cadence Virtuoso Environment.Item Open Access Analysis of address allocation protocols for mobile ad hoc networks(Dhirubhai Ambani Institute of Information and Communication Technology, 2011) Sati, Mohit; Srivastava, Sanjay; Divakaran, SrikrishnanIn almost all networks, it is necessary to have a unique identifier for each node. This identifier is used to find out route locating a particular node. So an address is must for any node for unicast communication. Addresses can be preconfigured manually or can be assigned dynamically using a server (e.g. DHCP server). Manual configuration of ad hoc network is not possible for large scale networks. And setting up a server is not possible due to lack of infrastructure in Ad Hoc Networks. So it is necessary to have a mechanism by which we can allocate addresses to the nodes dynamically without any prior setup. Lack of infrastructure and mobility of nodes makes address allocation a challenging task in MANET. We present worst case message complexity analysis of a number of proposed address allocation protocols, which can be useful for estimating upper bounds for overhead and latency involved in address allocation as well as partitioning and merging. We also show that the worst case analysis is not a useful indicator of real world performance of the protocols. Buddy approach [5] is one of the many proposed approaches for address allocation. We model DPDA (A Distributed Protocol for Dynamic Address assignment in mobile ado networks)[6], a protocol based on buddy approach, to estimate the overhead involved in address allocation. We conduct simulations in NS-2 and compare with analytical results to validate our model. We perform simplified simulations using Python script which also validates the proposed model. We also do a simulation based comparison of MANETconf (MANET configuration) [8] and DPDA[6] in term of overhead and latency in address allocation, which shows that DPDA causes lower communication overhead and latency than Manetconf.Item Open Access Pulse shaping for linear time varying channels(Dhirubhai Ambani Institute of Information and Communication Technology, 2011) Doshi, Savankumar; Chakka, VijaykumarPulse shaping is the one of the important an critical area for wireless communication. In this article we show the relation between pulse shaping for wide sense stationary uncorrelated scattering (WSSUS) channels and the notion of approximate eigenstructure for time-varying channels. Optimal link adaption to the scattering function of WSSUS channel is still an unsolved problem. In ulticarrier transmission such link adaption is performed by pulse shaping by properly adjusting transmitter and receiver filters. We consider pulse shaping for general signaling scheme called Weyl-Heisenberg signaling which includes Orthogonal Frequency Division Multiplexing (OFDM) and Offset Quadrature amplitude modulation (OQAM). We establish a general mathematical framework for joint transmitter and receiver pulse shape. Pulse design problem in the view of optimal averaged SINR is an interplay between localization and optimization strategies. The Localization problem can be expressed in terms of eigenvalues of approximate eigenstructure of Linear Time Varying (LTV) channel operators. In this thesis, we will show approximate eigenstructure and its relation with pulse design and several iterative algorithms for optimization.Item Open Access Adaptive analog line driver using digital tuning(Dhirubhai Ambani Institute of Information and Communication Technology, 2010) Singh, Harsh Verdhan; Sen, SubhajitTransmission lines are widely used for transmitting electrical signals. A line driver is a part of the analog front-end transmitter for wired line communication. It is a voltage buffer that provides the necessary output current to drive the small load impedance of a terminated transmission line. The adaptive line driver must adapt to the load impedance of a terminated transmission line for minimizing reflections. The main requirements of an adaptive line driver are good matching to the input impedance of the transmission line over process variations, high output swing, unity gain. Existing adaptive line drivers use analog tuning methods for adapting to the load impedance. This thesis proposes a new technique for tuning output impedance of the line driver. A digital tuning method is used to correct the output impedance of the line driver to match with the input impedance of the transmission line. The aim of using the digital tuning method is to achieve better tuning range over existing analog tuning methods. The tuning scheme uses a comparator followed by counter and current DAC(digital- to-analog converter). A comparator is used for comparing input and output signal of line driver and generates control signal which is applied to a counter that controls the current DAC. This feedback loop ensures unity gain between the input and out- put voltages and thereby ensures tuning of the output impedance of the line driver. The analog line driver is implemented in GPDK-180nm technology and simulated in Cadence Virtuoso Environment.Item Open Access Testbed based experimental analysis of transport protocols over wireless ad hoc networks(Dhirubhai Ambani Institute of Information and Communication Technology, 2009) Shah, Harshil Anilkumar; Srivastava, SanjayAd hoc networks are networks with no infrastructure and self-organized in nature. ad hoc networks allow nodes to form network when they come into range of each other provided nodes are configured in ad hoc mode. But these types of network are challenges like high bit error rates, route failures due to mobility, high noise, signal fading and low speed etc. to deal with. Due to this, protocols which are widely used in traditional wired networks may not perform well in MANETs. lower layers like MAC and network layer are either completely changed like 802.11 instead of 802.3 at MAC layer and introducing reactive routing protocols instead of only proactive routing at network layer or significant improvement schemes have been proposed for wireless networks in the existing legacy wired network protocols. But transport layer in MANET is mostly similar to wired networks except some improvements like TCP-ELFN and TCP-Feedback and new transport protocols like Ad hoc-TCP (ATCP), Transport Protocol for Ad hoc networks (TPA) and Ad-hoc Transport Pro- tool (ATP).performance degradation of TCP over wireless links is mainly due to wireless characteristics, TCP features like self-clocking, loss based congestion control, coupling of congestion and reliability, slow start. Several studies have been carried out to evaluate performance of TCP over MANETs but most of them are simulation based studies. But as simulation scenarios can not model exactly the unpredictable nature of wireless environment, we have decided to analyze performance of trans- port protocols over experimental test bed which can be more accurate evaluation of protocols in real-life situation. Performance of 2 transport protocols is analyzed.Item Open Access Scalable routing in mobile ad hoc networks(Dhirubhai Ambani Institute of Information and Communication Technology, 2009) Patel, Brijesh; Srivastava, SanjayIn Mobile Ad Hoc Networks (MANETs), performing routing is a challenging task in presence of the varying network parameters like node mobility, traffic and network size. It is very important to analyze the scalability characteristics of the routing protocols with respect to these parameters. ZRP is considered to be one of the most scalable routing protocols due to its multiscoping and hybridization features. We propose a general, parameterized model for analyzing control overhead of ZRP. A generic probabilistic model for data traffic is also proposed which can be replaced by different traffic models. Our analytical model is validated by comparisons with simulations performed on different scenarios. In our simulation results we have observed that the optimal zone radius lies where the proactive and reactive overhead components of ZRP are approximately equal as observed in [19]. We have also observed that optimal zone radius setting is different under different network conditions. Our simulations show that as the mobility increases the optimal zone radius value decreases, and as the traffic increases the value of optimal zone radius increases. Moreover, if a node operates away from the optimal zone radius setting then it has to bear and ditional routing overhead. Our simulations show that this deviation is quite high in case of low mobility (upto 35%) than in high mobility (upto 23%).Item Open Access Analysis of address allocation protocols for mobile ad hoc networks(Dhirubhai Ambani Institute of Information and Communication Technology, 2009) Sheth, Kavan J.; Srivastava, SanjayIn almost all networks, it is necessary to have a unique identifier for each node. This identifier is used to find out route locating a particular node. So an address is must for any node for unicast communication. Addresses can be preconfigured manually or can be assigned dynamically using a server (e.g. DHCP server). Manual configuration of ad hoc network is not possible for large scale networks. And setting up a server is not possible due to lack of infrastructure in Ad Hoc Networks. So it is necessary to have a mechanism by which we can allocate addresses to the nodes dynamically without any prior setup. Lack of infrastructure and mobility of nodes makes address allocation a challenging task in MANET. We present worst case message complexity analysis of a number of proposed address allocation protocols, which can be useful for estimating upper bounds for overhead and latency involved in address allocation as well as partitioning and merging. We also show that the worst case analysis is not a useful indicator of real world performance of the protocols. Buddy approach [5] is one of the many proposed approaches for address allocation. We model DPDA (A Distributed Protocol for Dynamic Address assignment in mobile ado networks)[6], a protocol based on buddy approach, to estimate the overhead involved in address allocation. We conduct simulations in NS-2 and compare with analytical results to validate our model. We perform simplified simulations using Python script which also validates the proposed model. We also do a simulation based comparison of MANETconf (MANET configuration) [8] and DPDA[6] in term of overhead and latency in address allocation, which shows that DPDA causes lower communication overhead and latency than Manetconf.Item Open Access Statistical co-analysis, robust optimization and diagnosis of USB 2.0 system for signal and power integrity(Dhirubhai Ambani Institute of Information and Communication Technology, 2009) Tripathi, Jai Narayan; Dubey, RahulSignal Integrity (SI) and Power Integrity (PI) are the most critical issues as semiconductor industry is moving towards higher operational speeds. Signal integrity and power integrity are such issues that should be looked at system level rather than looking at active and passive networks separately. System level analysis becomes a necessity when the individual subsystems work according to specifications, and even after that complete system doesn't work well. System level signal integrity and power integrity problems for high speed serial links have been taken into account in this thesis. Serial links are being used more and more rather than parallel links due to lesser skew and lower pin counts. Specifically USB 2.0 IP is used for this thesis work, but the analysis is generic for all serial links. This thesis considers SI and PI as a dual and a common model is used which considers both SI and PI. A statistical co-analysis of SI and PI for high speed serial links is used, which can be used for a cost effective solution too. Statistical methods are used for efficient simulations and to extract maximum information contents in the least simulation combinations. Based on this co-analysis, the system is diagnosed or modified for better SI and PI. In the end, reflection gain concept is also taken in to account for the diagnosis of the system. All in all, USB 2.0 system is diagnosed for better SI and PI. System level robustness analysis of high speed serial links are taken into account with effect of external environment. A strong correlation between measured and simulated results is shown. A generic methodology for SI and PI for high speed serial links is presented with complete analysis of package, board, termination, squidd card, decoupling network etc..Item Open Access Identifying small world network properties in ad-hoc networks(Dhirubhai Ambani Institute of Information and Communication Technology, 2009) Garg, Neha; Sunitha, V.Small World Network is a densely connected network with low degree of separation. These types of networks have high clustering property like regular network as well as have low average path length like random network. Thus, Small World Networks are both Locally and Globally ecient as compared to other networks. The above prop- erties can be described using parameters like characteristic path length (L), clustering coefficient (C), local efficiency (Eloc) and global efficiency (Eglob). Through experiments, done in the past, it has been found that many real world networks exihibit the properties of small world network. This has given rise To finding models for real world networks so that the models reflect small world ness of the real world network. This thesis uses the model of converting a square grid into a small world model by introducing some special nodes. The equations to compute the small world parameters for this model with one and or two special nodes derived in this thesis.