Theses and Dissertations
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Item 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 Optical wireless sensor network design for a conducting chamber(Dhirubhai Ambani Institute of Information and Communication Technology, 2011) Borkar, Abhishek; Ranjan, PrabhatNow a day’s majority of the wireless sensor networks (WSNs) are based on Radio Frequency (RF) communication technology. But RF when used in an environment like that of metallic, conducting chamber exhibits large amount of interference due to multipath effects which degrades the performance of the sensor network. Infrared (IR) communication technology can be used in sensor networks which is capable of overcoming the drawbacks exhibited by RF. Suitable IR link can provide high efficiency and mobility. A wireless sensor network has to be deployed inside a metallic chamberknown as Tokamak, used to produce controlled nuclear fusion. The sensor network
should be capable of capturing images and monitoring environmental parameters viz.
temperature and light intensity inside the chamber and transmitting the data outside.
One such design of sensor network based on IR communication technology has been
presented in this thesis. A design of sensor node with a camera, temperature sensor, light intensity sensor and IR transceiver interfaces is presented. Also a design of an optical gateway to transmit the data outside the metallic chamber is presented.
Item Open Access Wireless LAN 802.11 security using elliptic curve cryptography(Dhirubhai Ambani Institute of Information and Communication Technology, 2011) Singh, Saurabh; Das, Manik LalIEEE 802.11 is a standard defines the specification of Wireless Local Area Network (WLAN), came into existence in 1997. As communication medium is wireless, security is a major concern to protect the data from adversary. Existing WLAN security is primarily based on Symmetric Key Cryptography (SKC). But, major disadvantage with SKC is establishment of secret key for secure data delivery. Public key cryptography(PKC) has many advantages over Symmetric key cryptography like key management key distribution over insecure channel etc. However, PKC requires a large key size in comparison to SKC to provide same level of security. This makes PKC costly operation and not suitable for the environment like WLAN where limited memory is available for WLAN devices. In recent years, Elliptic Curve Cryptography (ECC) has gained a lot of attention from research communities, because ECC seems to promise simillar or a better level of security with smaller key size in comparison with conventional PKC (e.g. RSA, DSS). These features make them workable under constraint environment. In this thesis, we have studied the security evolution of WLAN 802.11 with Wired Equivalent Privacy (WEP) and Wi-Fi Protected Access (WPA). We have observed some limitations of WEP and WPA. We, then, present a new protocol using ECC for mutual authentication and session key establishment. We compare our protocol with simillar protocols for wireless security and show that the proposed protocol is efficient w.r.t. space, bandwidth and computational cost at Client side. The security analysis of proposed protocol shows that it may achieve forward secrecy with respect to Client, joint key control, key integrity and resists guessing, replay, impersonantion attacks. A thorough forrmal security analysis is required to be done.Item Open Access CLAPDAWN: cross layer architecture for protocol design in a wireless network(Dhirubhai Ambani Institute of Information and Communication Technology, 2011) Jardosh, Sunil; Ranjan, PrabhatArchitecture plays a key role in overall success of the network protocol stack. It is essential to have robust architecture for the complex system having multiple cross protocol interactions. In the literature more emphasis is given to the cross layer protocol design than the cross layer architecture. Cross Layer Architectures [1, 2, 3, 4] available in literature are not addressing the problems of cross layer interaction at their depth. Our work focuses on cross layer architecture design that supports multiple cross layer protocols and cross layer interactions. It addresses the problem of lack of support for multiple cross layer interactions, feedback loops, a longer development time and smooth rollover from cross layer interaction. Our proposed Cross Layer Architecture for Protocol Design in A Wireless Network (CLAPDAWN) addresses these problems faced by many of the previously proposed architectures. We have worked on two critical problems of IEEE 802.15.4 based event driven wireless sensor networks: topology control problem and prioritized event handling problem. The IEEE 802.15.4 standard configures network nodes as Reduced Function Devices (RFD) and Full Function Devices (FFD). In randomly deployed wireless sensor networks, the problem of configuring the network nodes as RFD or FFD, maintaining the network functionality is a topology control problem. To solve this, we have proposed a multipoint relay based Connected Dominating Set (CDS) construction algorithm. In literature the topology control problem has been solved by centralized [5, 6, 6] and distributed [7, 8, 9] approaches. Dynamic nature of wireless sensor network makes centralized approaches less applicable and distributed approaches have the problem of overlapping and redundant nodes in the generated CDS. In our work we have proposed ROOT-Initiative (ROOT-I) and ROOT-Ik topology control algorithms to construct oneconnected and k-connected networks respectively. Proposed algorithms control the overlapping and redundant nodes in the network. They reduce the number of active nodes in the network that helps in extending the network lifetime. Further, the tradeoff between energy consumption and fault tolerability is analyzed for k-connectedness. Our results show that in randomly deployed dense networks, the algorithm has better approximation ratio with acceptable time and message complexity. The solution for the prioritized event handling is based on IEEE 802.15.4 MAC scheduling and channel access mechanism. IEEE 802.15.4 has Guaranteed Time Slot(GTS)mechanism for guaranteed data delivery. The GTS mechanism is not ufficient to provide solutions for the critical event handling problem. It has problems of reservation delay and limited number of GTS slots. To handle critical events in IEEE 802.15.4 based networks, we have proposed Explicit Prioritized Channel Access Protocol(EPCAP) and Implicit Prioritized Channel Access Protocol(IPCAP) mechanisms. The proposed mechanisms achieve higher delivery ratio for important events with smaller delay. The IPCAP and EPCAP are modeled using Markov chain and M/G/c queuing model respectively and tested through simulation. In ROOT-I and ROOT-Ik, network layer and MAC layer communicate to decide the node type (RFD or FFD) and in EPCAP and IPCAP prioritized events are handled by MAC based on information provided by application layer. As mentioned above CLAPDAWN is designed to support cross layer interactions in the system. To provide proof of concept for the CLAPDAWN we have modeled ROOT-I, ROOT-Ik, EPCAP and IPCAP as cross layer interactions in CLAPDAWN and we discuss how various components of CLAPDAWN communicate to implement these protocols. Furthermore to provide comparative analysis we have implemented ECLAIR [3] cross layer architecture with the CLAPDAWN.We have implemented the complex video streaming cross layer protocol [10] on both the architectures and derived the performance results. To make more rigorous comparison of both the architectures we have implemented conflicting cross layer interactions in the system. Our results show that CLAPDAWN has relatively better performance results than the ECLAIR. That shows CLAPDAWN provides better and stable platform for cross layer protocol development.Item Open Access Robust surface coverage using deterministic grid based deployment in wireless sensor networks(Dhirubhai Ambani Institute of Information and Communication Technology, 2010) Kulkarni, Rucha; Srivastava, SanjayThe rapid progress in the field of wireless communication ans MEMS technology has made wireless sensor networks (WSN) possible. These networks may have low cost sensors deployed which are capable of sensing any activity in the vicinity, storing the information etcetera to carry out a certain task. An important problem receiving increasing consideration is the sensor coverage problem, that is, how well the sensors observe the physical space? Coverage can be considered as a measure of quality of service (QoS) of a sensor network [17]. Using equilateral triangle grid based deployment of the sensors, it is necessary to place the sensor nodes such that they are not too close so that the overlapping of the covered area is minimum. But, at the same time, not too far away that it leads to some uncovered areas known as the coverage holes. Thus, the sensing capabilities of the sensor nodes must be fully utilized in order to maximize coverage of the FoI. To find the coverage of the given uneven surface, the concepts in computational geometry, especially the Voronoi diagrams have been extensively used. When the sensor nodes are deployed using an aircraft, the accuracy of the sensor deployment is affected due to various factors like terrain properties, timing errors in deployment mechanism and more. Hence, it is necessary to take into consideration these placement errors while calculating the coverage of the surface. Existing work on the coverage of the given surface provides mathematical formulation for 2-D surfaces [5]. But, in real world applications, the surfaces are not 2-D in nature. But have many perturbations. This work intends towards deriving mathematical formulas based on Voronoi Diagram concept for such perturbed surfaces which calculates the value, the sensing radius should be set to, so that the entire region is covered. It also derives formulas when horizontal and vertical errors are introduced individually and when introduced together. This work also proposes an algorithm for calculating the coverage of the region under consideration when random errors are introduced in the deployment of the sensor nodes. It also provides information about total area covered for different values of the sensing radius of the sensor nodes. This information is required by different applications having different coverage needs.Item Open Access Game theory based strategies for cooperation in ad hoc wireless networks(Dhirubhai Ambani Institute of Information and Communication Technology, 2010) Rajput, Nitin Singh; Srivastava, Sanjay; Divakaran, SrikrishnanIn self-organized ad-hoc wireless networks, nodes belong to different authorities, pursue different goals, have constrains like energy; therefore, cooperation among them cannot be taken for granted. Non cooperation of nodes causes increase in probability of packet drop and increase in probability of route or network failure, which leads to poor network performance. On other hand if nodes always cooperate, network does not last for a long as nodes are energy constrained. Several schemes are proposed in literature based on incentive and reputation mechanism. All of them outperforms in their own set of assumptions and have certain issues.Researchers started looking at game theory as a probable solution and proposed some schemes, but yet to come up with better solutions. We focus on optimization of service received by a node from network and delivered to network considering energy as constraint. We first derive the probability by which a node accept the relay request of other nodes based on energy constraint. Then apply game theory based schemes Generous Tit For Tat (GTFT), Neighboring GTFT (N-GTFT) and contrite Tit For Tat (C-TFT) for acceptance of relay requests; well known in economics, behavioral science and biology for cooperation. We find that all above mention scheme converges towards parato optimal values of service received and deliver to network in presence and absentia of noise in network. We find that when network has pair wise mixed strategies (any two from GTFT, N-GTFT and C-TFT) then also convergences remain same as it is for single strategy. But when there are 50% non cooperative nodes (Always Drops strategy), C-TFT is the dominating strategy. Also C-TFT copes up with 10% or more noise in the network as other strategy fail to do so, however they cope well with lesser amount of noise. At the end CTFT evolve as the dominating strategy when all strategies including Always Drops simulated under evolutionary method of comparison in noisy and noise free network. C-TFT out performs because it switches to mutual Tit For Tat after cooperating against fixed unilateral non cooperation from other nodes and also cope up with own unintentional defection caused by noise.
Item Open Access Lifetime analysis of wireless sensor nodes using queuing models(Dhirubhai Ambani Institute of Information and Communication Technology, 2010) Anand, Guneshwar; Srivastava, SanjayProlonging the lifetime of wireless sensor networks (WSN) is one of the key issues for wireless sensor network applications. For increasing the lifetime of network, each node should conserve its energy. Sensor nodes consume different power in different operating modes. It also consumes significant amount of power while switching from one mode to another mode. So it is important that how frequently a node is changing its mode. To address this question we have used queuing theory based control policy, which finds the optimal parameter for switching between modes. We have analysed two different control policies namely, N-policy and T-policy and their effect on the lifetime of a sensor node. In N-policy, a sensor node switches its mode only when total number of packets are N. We find an optimal value of N that minimizes the energy consumption per unit time. Similarly, in T-policy whenever system becomes empty it goes on vaccation for a fixed duration T. It changes its mode only again after T unit of time and stays in the same mode as long as there is a packet. In this case also we find the optimal value of T that minimizes the energy consumption per unit time. But this improvement in lifetime comes at the cost of longer delay and larger waiting time. We have given the expression for the latency delay. Depending on the application requirement one can tune the parameters to get the best result between the energy saving and latency delay.Item Open Access Wireless sensor network based automatic meter reading: WSNAMR(Dhirubhai Ambani Institute of Information and Communication Technology, 2009) Sutariya, Mahesh R.; Ranjan, PrabhatAutomatic Meter Reading is technology evolved from 1995[3] or before, for remote collection of utilities measurement data which involve Electricity, Gas and Water etc. In this process of evolution every time new idea was methodology being used for implementation. In this thesis same task of meter reading will be performed wirelessly by using zigbee standard developed for the low power wireless sensor network. Concentration is on electrical energy. Goal of this work is to have a Remote collection of measured energy value as well as to have an on/off control of this energy supply which will indirectly enable wireless monitoring of energy consumption, prepaid billing etc through web based interface provided. So work will involve development of hardware and firmware and web based software to achieve this functionality. Once energy consumption data is available to us, it can be used for purpose of dynamic tariff management, dynamic load management, power quality monitoring, peak power consumption etc.Item Open Access Channel estimation and tracking OFDM and MIMO systems(Dhirubhai Ambani Institute of Information and Communication Technology, 2009) Singh, Smriti; Vijaykumar, ChakkaIn this thesis, To estimate and track the slow Time varying channels in OFDM and MIMO systems. In first part: we have used a two-dimensional recursive least square adaptive channel estimation technique is used. In orthogonal frequency division multiplexing (OFDM) system, time- and frequency-domain two-dimensional minimum mean square error (2D-MMSE) channel estimation is optimum. However, accurate channel statistics, which are often time varying and unavailable in practice, are required to realize it.2DRLS adaptive channel estimation does not require accurate channel statistics, and at the same time can make full use of time and frequencydomain correlations of the frequency response of time-varying wireless channels. With properly chosen parameters, 2D-RLS adaptive channel estimation can converge into the steady state in only several OFDM symbols time. Although the 2D RLS algorithm creates adaptive letters with a fast convergence speed, this algorithm diverges when the inverse correlation matrix of input loses the properties of positive definiteness or Hermitian symmetry. The diverging of the 2D RLS algorithm same as standard RLS limits the application of this algorithm. We proposed a QR decomposition-based 2DRLS (inverse QR-2DRLS) algorithm, which can resolve this instability. Instead of propagating inverse of correlation matrix of the input signal, it propogates square root of inverse correlation matrix of the input signal. Therefore, this algorithm guarantees the property of positive definiteness and is more numerically stable than the standard RLS algorithm. The parallel implementation of the inverse QR-2DRLS algorithm permits a direct computation of the least squares weight coefficients matrix MATLAB simulations demonstrate that performance of QR-2D-RLS adaptive channel estimation is same as of 2D-RLS adaptive channel estimation and is very effective and suitable for a broad range of channel conditions. In the second part of the thesis: Since, In MIMO systems, accurate channel estimation is necessary to fully exploit the benefits of spatial diversity offered by such systems. And for time-varying channels, these channel estimates should also be updated accordigly to track the variation of channel. we have used One such method of channel estimation using adaptive SVD updates for channel estimation and tracking of slow-time varying channels in MIMO system. The channel estimates are then further used for symbol detection using V-BLAST/ZF detection algorithm which ensures interference reduction and give better BER vs. SNR performance than SVD based MIMO system.Item Open Access Energy efficient data gathering protocol for wireless sensor network(Dhirubhai Ambani Institute of Information and Communication Technology, 2008) Rao, Parth A.; Srivastava, SanjayWireless Sensor Network is made up of hundreds and thousands of miniature electronic devices called node, which have sensors built on them. Functionality of a sensor is entirely application dependent. They can perform a large number of functions from measuring the forces of nature like temperature, humidity, geophysical activity, sound vibrations to motion detection and military surveillance. Apart from sensing or measuring, the nodes are responsible for efficiently collecting the sensed data by performing appropriate activities on the collected data and there by weeding out redundant data so as to reduce transmission overload on nodes. Thus the nodes are responsible for gathering data and routing the data to the base station. Data Gathering can be performed in number of ways after nodes are deployed in the sensing field depending on their application. The manner in which nodes are deployed in the sensing field also affects the lifetime of the sensor network. It is not always possible that all nodes after deployment in the sensing field are able to communicate with the base station. Moreover efficient utilization of the energy is a must for sensor nodes, because these sensors are battery powered devices, and after they are deployed in the sensing field it is not feasible to change the battery of the nodes. So energy preservation of nodes in sensor network is a crucial requirement to be taken care of. The other prime matter worth considering is that during the whole life time of the sensor network care should be taken that load distribution on all the nodes in the sensing field is equal. All nodes should either die randomly at random location in the sensing field at random time intervals, or all nodes should start dying at more or less the same time. We have proposed an energy efficient protocol for data gathering in wireless sensor networks, which through hierarchical cluster formation reduce the number of high energy transmissions per round of data gathering and takes care of the load balancing issue by randomized rotation of the cluster heads. Routing of data is done in multi-hop fashion to ensure that the most remotely located node is also able to communicate with the base station through the best available intermediary nodes.