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This paper focus on developing a new practical classification for ad-hoc networks, were all the past classifications revolve upon three main categories respectively, mobile ad- hoc network (MANET), Vehicle ad-hoc network (VANET) and Flying ad-hoc network (FANET). My new classification will illustrate Underwater vehicle ad-hoc network (UWVANET) as the fourth category in ad-hoc main classification, showing the powerful and the weakness of each category defined.

Network Coding (NC) is a new area which brings radical change in the way we treat information flow in networks. NC considered being a layer 3 operation has been shown to improve the throughput of wired networks especially for broadcast and multicast traffic. Linear network coding (LNC) in which packets are combined using simple linear operations over finite fields can indeed achieve the multicast capacity. Random LNC (RLNC) is attractively used for distributed scenario where the codes are generated by various nodes in random fashion. The data dissemination latency scales as O(N2) (N is the number of nodes) in naive broadcast scenario. However with RLNC the data dissemination latency scales between O(N) and O(N2) depending on the network connectivity. NC is at the heart of two problems that we have considered in this thesis. Firstly we consider collaborative distributed indoor target tracking using wireless sensor networks (WSNs) where we show how RLNC can be used for effective information dissemination and analyzed its impact on tracking performance for the case of indoor target tracking. Our simulation results demonstrate that for a target root mean square (RMS) value of tracking error the RLNC scheme would require less number of time slots in comparison with the two competing schemes. Secondly we consider the performance of NC in relay assisted contention based ad hoc networks considered like the IEEE 802.11 compliant ones. We specifically show as how MAC layer NC can be used at both relay, source & destination nodes to improve throughput in contention based wireless networks. Our simulation results demonstrate an increment in system throughput by 15-20% for the case with NC.

In wireless ad-hoc networks, communication is done mainly through intermediate nodes or relay nodes. The mobile nodes in ad-hoc network have limited energy, so the intermediate nodes or relay nodes do not always co-operate to transfer other nodes’ information. If all nodes start performing in the same manner, network performance will drop drastically and the whole network will get disconnected. Co-operation strategy is applied on communities instead of each node to get better network performance. A Community is created based on how strong a node is socially connected to other nodes, because a node will co-operate to those nodes who are having strong social ties with it (especially in energy constrained and selfish environments). Due to this, nodes in the same community will always co-operate to one another. After the community formation, Generous Tit - for - Tat (GTFT) co-operation strategy and other co-operation strategies are applied between communities for further communication. The community formation will make these strategies more scalable and results show that the performance of these strategies are good under heavy non co-operative or selfish networks.

In 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.

A 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.

In self-organized ad hoc networks, all networking functions rely on the contri- bution of the relay nodes. Nodes have to forward packets for each other in order to enable multi-hop communication. In recent years, researchers have identi ed the problem of stimulating cooperation in ad hoc networks and proposed several solutions to give nodes incentive to contribute to common network services. These solutions are based on incentive mechanisms like reputation based system or virtual currency based system. This paper aims at determining conditions under which, such cooperation without incentives can exist, while taking the network topology into account. We have focused on the most basic networking mechanism, namely, packet forwarding and proposed a game theoretic approach for achieving cooperation. We have de ned a game model where nodes act as players, their actions (forward or drop a packet) de ne strategies and they are given payo s based on the payo functions designed in terms of network parameters. We have considered di erent parameters for simulation like tramsmission range, di erent strategies, initial condition of nodes, energy cost for sending or forwarding packets, tra c rate, noise e ect, mobility, etc. Our simu- lation result shows how cooperation is achieved in network with nodes getting better payo s. Later we have extended our work to cover network with mobile nodes.

In this paper we suggest a promising solution to come over the problems of delivering e-learning to areas with lack or deficiencies in infrastructure for Internet and mobile communication. We present a simple, reasonably priced and efficient communication platform for providing e-learning. This platform is based on wireless ad-hoc networks. We also present a preemptive routing protocol suitable for real-time video communication over wireless ad-hoc networks. Our results show that this routing protocol can significantly improve the quality of the received video. This makes our suggested system not only good to overcome the infrastructure barrier but even capable of delivering a high quality e-learning material.

Wireless adhoc networks are autonomous, infrastrutureless networks where there are no dedicated routers or base stations and nodes are expected to cooperate in Wireless performing routing duties to keep network connected. Cooperation can be assumed if all nodes belong to single authority (e.g. military service or disaster management). But in applications where nodes do not belong to single authority and have limited resources (energy of battery driven devices), like pervasive computing or ubiquitous computing environment, one can not deny possibility of node selfishness. Also as there is no central authority to control node behavior, one can not deny possibility of node maliciousness. Many cooperation enforcement schemes are proposed in literature, and every scheme is shown to perform better under its own set of assumptions. These assumptions are different for different schemes. So, we aim at defining common set of assumptions and comparing selected schemes on this common ground with respect to packet delivery ratio, energy consumption, routing and other control overhead. We find that with the traffic scenario where nodes do not need services of one another at the same time, the cooperation schemes are not effective in dealing with node selfish ness. We also find that, while dealing with malicious nodes, all cooperation schemes perform better than Dynamic Source Routing(DSR) protocol in improving packet de- livery ratio(PDR), but this improvement comes at the cost of significant increase in routing control packets overhead and energy consumption of cooperation enforcement schemes is higher than that of DSR. Also they fail in punishing misbehaving nodes and the PDR of malicious nodes is comparable to that of good nodes.

IEEE 802.11 DCF (IEEE 802.11 Distributed Coordination Function) is widely used MAC protocol for wireless channel access. Although it is developed for single hop networks where all nodes are in the same radio range, it can be directly used for wireless multiphop hoc networks. But performance of IEEE 802.11 DCF in wireless ad hoc networks su ers as it has been developed considering single hop networks only. Many amendments has been proposed to enhance its performance in multihop ad hoc networks. One such scheme is DWMAC (Dynamic Waiting Medium Access Control). In this work, performance of IEEE 802.11 DCF and DWMAC are compared for different network scenarios and traffic patterns. It has been observed that the performance of DWMAC can be further improved if we alter the restricted mode operation of the nodes. We have proposed a new modified protocol DWMAC-Modied and have shown by simulations that DWMAC-Modied offers singnificant improvements.

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.

In 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.

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.

Wireless Ad Hoc network is a decentralized wireless network which allows nodes to join and create networks without any infrastructure. These kinds of networks are advantageous because they can be readily deployed anywhere, anytime. Mobile Ad Hoc Network (MANET) is a special type of ad hoc network where nodes are mobile. Due to mobility of the nodes, network topology may change rapidly and unpredictably. MANETs are expected to plat a vital role in a variety of applications and are therefore studied extensively. It is imperative to analyze these networks, to assess the suitability of their use in different scenarios and to identify the techniques to improve their performance. In last few years, many models have been proposed to analyze MANETs. Many of then have an unrealistic assumption of an infinite buffer in each node. Moreover, in MANETs, as nodes are mobile, a packet may revisit the same node which creates feedback loops of a packet. These loops make modeling and analysis of MANETs difficult as the network becomes cyclic. This work analyzes MANET with finite buffer nodes. Open finite queuing network with gated queue, intermittent links and servers is used. The expansion method technique has been used to study the open finite queuing network with stable links and servers. We modify the method for intermittency. Numerical results are derived and compared with simulation results to show effectiveness of the method.