An ad-hoc network is the cooperative engagement of a collection of mobile nodes without the required intervention of any centralized access point or existing infrastructure. In this paper we present Ad-hoc On Demand Distance Vector Routing (AODV), a novel algorithm for the operation of such ad-hoc networks. Each Mobile Host operates as a specialized router, and routes are obtained as needed (i.e., on-demand) with little or no reliance on periodic advertisements. Our new routing algorithm is quite suitable for a dynamic selfstarting network, as required by users wishing to utilize ad-hoc networks. AODV provides loop-free routes even while repairing broken links. Because the protocol does not require global periodic routing advertisements, the demand on the overall bandwidth available to the mobile nodes is substantially less than in those protocols that do necessitate such advertisements. Nevertheless we can still maintain most of the advantages of basic distance-vector routing mechanisms. We show that our algorithm scales to large populations of mobile nodes wishing to form ad-hoc networks. We also include an evaluation methodology and simulation results to verify the operation of our algorithm.

this paper, we present the design, implementation, and evaluation of the INSIGNIA QOS Framework that supports the delivery of adaptive services in mobile ad hoc networks. A key component of our QOS framework is the INSIGNIA signaling system, an in-band signaling system that supports fast reservation, restoration, and adaptation algorithms that are specifically designed to deliver adaptive service. The signaling system is designed to be lightweight and highly responsive to changes in network topology, node connectivity, and end-to-end quality of service conditions. The structure of the paper is as follows. We discuss our framework in the context of the related work and present the main design considerations that have influenced our thinking in Sections 2 and 3, respectively. Section 4 presents an overview of the INSIGNIA QOS framework. The detailed design of the INSIGNIA signaling system is given in Section 5. We evaluate our QOS framework in Section 6, paying particular attention to the performance of the signaling system under a variety of network conditions. Our simulation results show the benefit of the INSIGNIA QOS framework under diverse mobility, traffic, and channel conditions in support of fast reservation, restoration, and adaptation. Finally, we present our conclusion in Section 7

Ad-hoc networking is a concept in computer communications, which means that users wanting to communicate with each other form a temporary network, without any form of centralized administration. Each node participating in the network acts both as host and a router and must therefore be willing to forward packets for other nodes. For this purpose, a routing protocol is needed.

There is a growing need to provide better service differentiation in mobile ad hoc networks; however, this is challenging. These networks are characterized as being multihop in nature where the wireless topology that interconnects mobile hosts/routers can change rapidly in unpredictable ways or remain relatively static over long periods of time. Power and bandwidth constrained, mobile ad hoc networks typically only support best effort communications where the transport protocol's "goodput" is often lower than the maximum radio transmission rate after encountering the effects of multiple access, fading, noise, and interference. In this article we evaluate three routing protocols with INSIGNIA, an in-band signaling system that supports adaptive reservation-based services in mobile ad hoc networks. INSIGNIA represents a general-purpose approach to delivering quality of service in mobile ad hoc network supporting "operational transparency" between a number of IETF mobile ad hoc network routing protocols that include Ad Hoc On-Demand Distance Vector, Dynamic Source Routing, and the Temporally Ordered Routing Algorithm. We evaluate the performance gains delivered when using INSIGNIA with these MANET routing protocols in support of UDP and TCP traffic. The INSIGNIA ns-2 code used for the study reported in this article is available from the Web at comet.columbia.edu/ insignia.

Link reversal algorithms provide a simple mechanism for routing in communication networks whose topology is frequently changing, such as in mobile ad hoc networks. A link reversal algorithm routes by imposing a direction on each network link such that the resulting graph is a destination oriented DAG. Whenever a node loses routes to the destination, it reacts by reversing some (or all) of its incident links. Link reversal algorithms have been studied experimentally and have been used in practical routing algorithms, including TORA [11].

Existing on-demand ad hoc network routing protocols continue using a route until a link breaks. During the route reconstruction, packets can be dropped, which will cause significant throughput degradation. In this thesis, we add a link breakage prediction algorithm to one on-demand routing protocol: the Dynamic Source Routing (DSR) protocol. The mobile node that implements the prediction algorithm uses signal power strength from the received packets to predict the link breakage time, and sends a warning to the source node of the packet if the link is soon-to-be-broken. The source node can perform a pro-active route rebuild to avoid disconnection. Experiments demonstrate that adding link breakage prediction to DSR, even considering the increased number of control messages (at most 33.5%), can significantly reduce the total number of dropped data packets (at least 20%) due to link breakage by reducing the number of broken links. We believe that TCP can potentially benefit well from the pro-active route maintenance to increase throughput, which is affected by broken links. We also propose a modification plan for AODV and make recommendations about further improvement on DSR based on the link breakage prediction. ACKNOWLEDGEMENT I would like to thank my supervisor, Professor Thomas Kunz, for his guidance and direction for this thesis, for the many interesting discussions we had. I greatly benefit from his detailed comments and insights that help me clarify my ideas and present the materials in a suitable way. I would like to thank the teachers at the School of Computer Science and Department of Systems and Computer Engineering, Carleton University for all the things I learned here. I would also like to thank Mr. John Knox for his assistance and support of computer s...

We propose an algorithm for design and on the fly modification of the schedule of a wireless ad hoc network for provision of fair service guarantees under topological changes. The primary objective is to derive a distributed coordination method for schedule construction and modification for any wireless ad-hoc network that operates under a schedule where transmissions at each slot are explicitly specified over a time period of length T. We first

Abstract—Mobile robot teams are increasingly deployed in various applications involving remote operations in unstructured environments that do not support wireless network infrastructures. We propose a class of protocols based on the connectivity-through-time concepts that exploit the robot movements to extend the traditional notions of network connectivity. These protocols enable the formation of ad hoc networks of mobile robots without the infrastructure of access points by utilizing the robots as routers. These protocols are implemented as a collection of daemons that track connectivity changes, compute single and multiple hop connectivity, route the packets via robots with suitable buffering, and adapt the transport parameters to the connection characteristics. The implementation employs UDP with window-based flow control that is tuned to the nature of connections. We present experimental performance results based on our implementation on robot teams to illustrate the salient features of this approach.

In this paper, we present a new link-state routing algorithm called Approximate Link state (XL) aimed at increasing routing efficiency by suppressing updates from parts of the network. We prove that three simple criteria for update propagation are sufficient to guarantee soundness, completeness and bounded optimality for any such algorithm. We show, via simulation, that XL significantly outperforms standard link-state and distance vector algorithms—in some cases reducing overhead by more than an order of magnitude— while having negligible impact on path length. Finally, we argue that existing link-state protocols, such as OSPF, can incorporate XL routing in a backwards compatible and incrementally deployable fashion.

Overheads incurred by routing protocols diminish the capacity available for relaying useful data in a mobile wireless ad hoc network. Discovering and understanding lower bounds on the amount of protocol overhead incurred for routing data packets is important for the development of efficient routing protocols, and for understanding the actual (effective) capacity available for network users. In this paper we use an information-theoretic approach for characterizing the minimum routing overheads of geographic routing in a mobile network. We formulate the minimum overhead problem as a rate-distortion problem. The formulation may be applied to networks with arbitrary traffic arrival and location service schemes. We evaluate lower bounds on the minimum overheads incurred for maintaining the location of destination nodes and consistent neighborhood information in terms of node mobility and packet arrival process. We also characterize the deficit caused by the routing overheads on the overall transport capacity of a mobile network.