An ad hoc network is a collection of wireless mobile nodes dynamically forming a temporary network without the use of any existing network infrastructure or centralized administration. Due to the limited transmission range of wireless network interfaces, multiple network "hops " may be needed for one node to exchange data with another across the network. In recent years, a variety of new routing protocols targeted specifically at this environment have been developed, but little performance information on each protocol and no realistic performance comparison between them is available. This paper presents the results of a detailed packet-level simulation comparing four multi-hop wireless ad hoc network routing protocols that cover a range of design choices: DSDV, TORA, DSR, and AODV. We have extended the ns-2 network simulator to accurately model the MAC and physical-layer behavior of the IEEE 802.11 wireless LAN standard, including a realistic wireless transmission channel model, and present the results of simulations of networks of 50 mobile nodes. 1

Abstract—Routing protocols for mobile ad hoc networks (MANETs) have been explored extensively in recent years. Much of this work is targeted at finding a feasible route from a source to a destination without considering current network traffic or application requirements. Therefore, the network may easily become overloaded with too much traffic and the application has no way to improve its performance under a given network traffic condition. While this may be acceptable for data transfer, many real-time applications require quality-of-service (QoS) support from the network. We believe that such QoS support can be achieved by either finding a route to satisfy the application requirements or offering network feedback to the application when the requirements cannot be met. We propose a QoS-aware routing protocol that incorporates an admission control scheme and a feedback scheme to meet the QoS requirements of real-time applications. The novel part of this QoS-aware routing protocol is the use of the approximate bandwidth estimation to react to network traffic. Our approach implements these schemes by using two bandwidth estimation methods to find the residual bandwidth available at each node to support new streams. We simulate our QoS-aware routing protocol for nodes running the IEEE 802.11 medium access control. Results of our experiments show that the packet delivery ratio increases greatly, and packet delay and energy dissipation decrease significantly, while the overall end-to-end throughput is not impacted, compared with routing protocols that do not provide QoS support. Index Terms—Bandwidth estimation, mobile ad hoc networks (MANETs), quality-of-service (QoS)-aware routing. I.

The current state of the art in evaluating applications and communication protocols for ad hoc wireless networks involves either simulation or small-scale live deployment. While largerscale deployment has been performed, it is typically costly and difficult to run under controlled circumstances. Simulation allows researchers to vary system configurations such as MAC layers and routing protocols. However, it requires the duplication of application, operating system, and network behavior within the simulator. While simulation and live deployment will clearly continue to play important roles in the design and evaluation of mobile systems, we present MobiNet, a third point in this space. In MobiNet, the communication of unmodified applications running on stock operating systems is subject to the real-time emulation of a user-specified wireless network environment. MobiNet utilizes a cluster of emulator nodes to appropriately delay, drop or deliver packets in a hop by hop fashion based on MAC-layer protocols, ad hoc routing protocols, congestion, queuing, and available bandwidth in the network. MobiNet infrastructure is extensible, facilitating the development and evaluation of new MAC layers, routing protocols, mobility and traffic models. Our evaluations show that MobiNet emulation is scalable and accurate while executing real code, including video playback.

This document describes each of the pieces we have added to ns , and gives some examples of how they can be used. This document assumes the reader is very familiar with using ns already, and it is not a substitute for reading and understanding the source. More information on our extensions to ns, and description of some of our results based on the simulator, can be found in a paper published in Mobicom98 [2]. Our extensions to ns are based on the ns-2.1b1 release. We would welcome feedback, improvements, and bug fixes at monarch@monarch.cs.cmu.edu.

This thesis develops new routing methods for large-scale, packet-switched data networks such as the Internet. The methods developed increase network performance by considering routing approaches that take advantage of more available network resources than do current methods. Two approaches are explored: dynamic metric and multipath routing. Dynamic metric routing provides paths that change dynamically in response to network traffic and congestion, thereby increasing network performance because data travel less congested paths. The second approach, multipath routing, provides multiple paths between nodes and allows nodes to use these paths to best increase their network performance. Nodes in this environment achieve increased performance through aggregating the resources of multiple paths. This thesis implements and analyzes algorithms for these two routing approaches. The first approach develops hybrid-Scout, a dynamic metric routing algorithm that calculates independent and selective dynamic metric paths. These two calculation properties are key to reducing routing costs and avoiding routing instabilities, two difficulties commonly experienced

This dissertation was presented by

Abstract. A Mobile ad-hoc network is a multihop wireless network, where nodes communicate with each other without any pre-deployed infrastructure. The most important problem on such dynamic networks is to find routing algorithms well performing in most cases. Cluster based algorithms are among the most effective and scaleable approaches. Up till now creation and maintenance clusters were mostly based on basic heuristic methods. Deploying mobile agents has several advantages in the ad-hoc environment due to their flexible, robust and autonomous nature, and their use seems promising for the clustering problem as well. In our proposed architecture every cluster has a clustering agent that is capable of making membership modification decisions, transferring nodes and splitting or merging clusters. Communication is used only between neighbouring agents to reduce the signalling overhead. Clustering decisions can be based on several network parameters modified by an adaptation mechanism to provide adequate performance even under dynamic conditions. I.

Unmanned aerial vehicles (UAVs), and unmanned aerial systems (UAS) as such in general, need wireless networks in order to communicate. UAS are very flexible and hence allow for a wide range of missions by means of utilizing different UAVs according to the mission requirements. Each of these missions also poses special needs and requirements on the communication network. Especially, mission scenarios calling for UAV swarms increase the complexity and call for specialized communication solutions. This work focuses on these specialties and needs and describes the selection process, adaptation and implementation of an ad-hoc routing protocol tailored to an UAV surrounding and a correspondingly adapted communication method. I.

Abstract—Recently, erasure coding has become widely used to compensate for the low packet delivery ratio of multi-hop wireless networks. Most existing works assume that the number of redundant erasure-coded packets is unlimited for a message. In this paper, we relax this assumption and integrate the packet quantity into a routing problem in order to achieve a good balance between energy cost and reliability (packet delivery ratio). In doing so, we encounter two major challenges in regards to our new routing problem: one is determining the optimal quantity of redundant packets and the other is determining the optimal routing path. We introduce a benefit value to reflect the trade-off between cost and reliability, and design a single metric (expected utility) by integrating benefit value, cost, and reliability. Based on the expected utility metric, we explore the optimality in both path coding and source coding models. In the path coding model, we design an optimal algorithm, and in the source coding model we propose a heuristic solution. Results from extensive simulations on our custom simulator verify our claims. Index Terms—Energy cost, erasure coding, multi-hop wireless networks, reliability, routing, utility. I.

A Mobile Ad-hoc Network (MANET) is a collection of mobile nodes that communicate and collaborate with each other without reliance on any pre-existing infrastructure. In MANETs, wireless links are subject to frequent breakages due to nodes high mobility. While several routing protocols such AODV and DSR have been designed for MANETs, many of operate efficiently under low network mobility conditions and do not adapt well with high mobility conditions. Therefore, considering mobility is a demanding task that should be performed efficiently and accurately. Here, we proposed novel mobility-aware routing protocol based on the well known Ad-hoc On Demand Distance Vector (AODV) routing protocol called: MA-AODV (Mobility Aware Ad-hoc On Demand Distance Vector) in an attempt to improve the handling of high mobility factor in ad-hoc networks. MA-AODV protocols perform periodic quantification of nodes mobility for the sake of establishing more stable paths between source/destination pairs, hence, avoiding the frequent link breakages associated with using unstable paths that contain high mobile nodes.