M Tech Dissertations
Permanent URI for this collectionhttp://drsr.daiict.ac.in/handle/123456789/3
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Item Open Access FPGA implementation of multiband and multimode modem for software defined radio (SDR)(Dhirubhai Ambani Institute of Information and Communication Technology, 2012) Timbadiya, Jaykant; Dubey, RahulNow a days Software Defined Radio(SDR) is becoming popular for wireless communication because of it’s flexibility to change as per requirement through software. The work presented here describes the different methods of designing a Multiband and Multimode MODEM, implementation on programmable device like FPGA and verification for different functionality and specification. The design presented here has ability to switch between different modulation scheme and different data rate. Multiband and Multimode modem includes BPSK and QPSK modulator and demodulator with Forward Error Correction and other base band processingItem Open Access Mobility models and its application in ad-hoc network(Dhirubhai Ambani Institute of Information and Communication Technology, 2011) Jain, Vikas Kumar; Patil, Hemant A.; Mulherkar, JaideepThe Performance of MANET application depends on several parameters like no. of nodes, node density, communicating traffic pattern, communication range of a node, routing protocol, battery power of a node, mobility etc. Out these mobility plays an important role. Mobility model describe the mobility pattern of mobile nodes and users like how their location, velocity, direction and acceleration will change with respect to time. There are some of the mobility models like Random Way Point, Gauss Markov mobility model, Reference Point Group mobility model and Manhattan mobility model. Since simulate on plays an important role in conducting the research and to know the performance ofmany MANET applications, hence it is important to choose the appropriate mobility model. Generally, all the simulation work is done by choosing the Random Way Point mobility model because of its simplicity but it is unable to capture a real life scenario. RWP has several limitations so it cannot be applied for each MANET applications. A lot of work has been done by the researchers to design mobility models which are able to capture real life scenario. Accurate realistic modeling is a very challenging task and involves huge efforts. This work intends towards proposing a method to answer about best fit mobility model for the given trace along with confidence level and parameters values of the model. If we use best fit mobility model according to the given trace then accuracy of the results will improve. This work mainly focuses on RWP and RPGM mobility model. Also the proposed method are applied on a ad hoc wireless sensor network application called Zebra Net trace, to answer about the best fit mobility model out of RWP and RPGM.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 Low noise amplifier design at 2 GHz(Dhirubhai Ambani Institute of Information and Communication Technology, 2011) Mavani, Kausha; Gupta, SanjeevLow Noise Amplifier (LNA) is one of the most important building blocks of any wireless receiver. In this an attempt has been made to study two types of LNA designs. The first design is the conventional which consists of the transistor, its biasing network and the input and output matching networks. The second design is an inductorless design which can be further customized to work over a large frequency range. The operating frequency studied in this thesis is 2GHz. A comparison has been made between the two designs and the values of gain and noise figure are satisfactory in both the designs.Item Open Access Hardware implementation of multiband and multimode modem for software defined radio/ cognitive radio(Dhirubhai Ambani Institute of Information and Communication Technology, 2011) Buddhbhatti, Dixit K.; Dubey, RahulPresent day programmable hardware and SDR (Software Defined Radio) have enabled radio processing to switch from analog to digital. The work presented here describes a method of designing a multiband & multimode modulator for SDR/ CR (Cognitive Radio) and its implementation on programmable hardware, such as FPGA (Field Programmable Gate Array). SDR has become a most important topic of research in the field of satellite communication. The prototype presented here shows ability to dynamically alter modulation and demodulation scheme in a Satellite Communication (Satcom) terminal to suit given conditional requirements. The Cognitive module will decide which modulation scheme and frequency band has to be used for signal transmission. Cognitive module provides control bit to select the modulation scheme and operating frequency. The work presented here demonstrates a practical design and implementation procedure for modem used in SDR/ CR platform and gives detailed description of the baseband signal processing logic design in the FPGA.Item Open Access Secure data delivery in mobile ad hoc network using multiple paths(Dhirubhai Ambani Institute of Information and Communication Technology, 2011) Maheshwari, Mayur; Das, Manik LalA mobile ad hoc network (MANET) is a self configurable, self organized, infrastructure less multi hop mobile wireless network.Characteristics of ad hoc network make security a critical issue i.e. any node can join the network without revealing its presence as well as any node can behave in either a passive way (eavesdropping the message) or in an active way (manipulating the message, signal interference or jamming the network). When a node has some confidential information needed to transmit to other node, it needs some secure data delivery protocols such that, information can reach to intended node confidentially without tempered. We have studied two secure data delivery protocols namely SPREAD and Xia et al‟s scheme. These protocols focus on how to deliver a secret message over insecure MANET using multiple paths. These protocols provide confidentiality and robustness but don‟t focus on authentication and integrity. Due to the lack of authentication, any node can impersonate the good node or the intermediate node can manipulate message and no one can detect this misbehaviour. We have proposed a scheme that aims to provide confidentiality, authentication, and robustness for a message when they are delivered across the insecure MANET. We have used the concept of SPREAD, where message transforms into multiple shares and then delivers the shares via multiple independent paths to the destination, so that if a small number of nodes that are used to relay the message shares are compromised, the whole message is not compromised. We are using basic idea of TESLA to provide authentication. Finally, when we analyzed our proposed protocol and compared it with SPREAD. Our analysis showed that the proposed scheme provides all basic security objectives as well as it protects against data tempering, impersonation, replay and known session key attacks.Item Open Access Cache performance evaluation in DSR protocol through cross-layering for mobile ad hoc networks(Dhirubhai Ambani Institute of Information and Communication Technology, 2009) Sharma, Kapil; Sunitha, V.Wireless mobile ad-hoc networks are being actively studied by many researchers these days. These networks are suitable to be used in various situations because of (i) their infrastructure-less property and (ii) the mobility of the nodes of the network. However, it is these features which give rice to problems in study of such networks. Further, routing is one of the basic issues in any network design. Inclusion of moving capability to the nodes, make the routing problem more complicated. One is always interested in increasing the throughput and reducing overhead while at the same time solving the issues related to routing. DSR is a protocol that is extensively used for routing in such networks. Cache management and route caching play a significant role in using DSR successively to attain the best behavior for these networks. This thesis looks at and suggests some methods for route caching in DSR.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 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.