Juan-Carlos Cano

Routing mechanisms for mobile ad hoc networks based on the energy drain rate

Untethered nodes in mobile ad hoc networks strongly depend on the efficient use of their batteries. In this paper, we propose a new metric, the drain rate, to forecast the lifetime of nodes according to current traffic conditions. This metric is combined with the value of the remaining battery capacity to determine which nodes can be part of an active route. We describe new route selection mechanisms for MANET routing protocols, which we call the minimum drain rate (MDR) and the conditional minimum drain rate (CMDR). MDR extends nodal battery life and the duration of paths, while CMDR also minimizes the total transmission energy consumed per packet. Using the ns-2 simulator and the dynamic source routing (DSR) protocol, we compare MDR and CMDR against prior proposals for energy-aware routing and show that using the drain rate for energy-aware route selection offers superior performance results. Methods keywords are system design and simulations.

A performance comparison of energy consumption for Mobile Ad Hoc Network routing protocols

The design of efficient routing protocols is a fundamental problem in a Mobile Ad-Hoc Network (MANET). Many different protocols have been proposed in the literature, each one based on different characteristics and properties. Some of these protocols have been studied and their performances have been evaluated in detail, focusing on aspects such as routing overhead latency and route length. We concentrate on the energy consumption issues of routing protocols. We present a performance comparison of the DSR, AODV, TORA and DSDV routing protocols with respect to energy consumption, evaluating how the different approaches and algorithms affect the energy usage in mobile devices.

HOP: achieving efficient anonymity in MANETs by combining HIP, OLSR, and pseudonyms

Offering secure and anonymous communications in mobile ad hoc networking environments is essential to achieve confidence and privacy, thus promoting widespread adoption of this kind of networks. In addition, some minimum performance levels must be achieved for any solution to be practical and become widely adopted. In this paper, we propose and implement HOP, a novel solution based on cryptographic Host Identity Protocol (HIP) that offers security and user-level anonymity in MANET environments while maintaining good performance levels. In particular, we introduce enhancements to the authentication process to achieve Host Identity Tag (HIT) relationship anonymity, along with source/destination HIT anonymity when combined with multihoming. Afterward we detail how we integrate our improved version of HIP with the OLSR routing protocol to achieve efficient support for pseudonyms. We implemented our proposal in an experimental testbed, and the results obtained show that performance levels achieved are quite good, and that the integration with OLSR is achieved with a low overhead.Offering secure and anonymous communications in mobile ad hoc networking environments is essential to achieve confidence and privacy, thus promoting widespread adoption of this kind of networks. In addition, some minimum performance levels must be achieved for any solution to be practical and become widely adopted. In this paper, we propose and implement HOP, a novel solution based on cryptographic Host Identity Protocol (HIP) that offers security and user-level anonymity in MANET environments while maintaining good performance levels. In particular, we introduce enhancements to the authentication process to achieve Host Identity Tag (HIT) relationship anonymity, along with source/destination HIT anonymity when combined with multihoming. Afterward we detail how we integrate our improved version of HIP with the OLSR routing protocol to achieve efficient support for pseudonyms. We implemented our proposal in an experimental testbed, and the results obtained show that performance levels achieved are quite good, and that the integration with OLSR is achieved with a low overhead.

Emergency Services in Future Intelligent Transportation Systems Based on Vehicular Communication Networks

Over the years, we have harnessed the power of computing to improve the speed of operations and increase in productivity. Also, we have witnessed the merging of computing and telecommunications. This excellent combination of two important fields has propelled our capability even further, allowing us to communicate anytime and anywhere, improving our work flow and increasing our quality of life tremendously. The next wave of evolution we foresee is the convergence of telecommunication, computing, wireless, and transportation technologies. Once this happens, our roads and highways will be both our communications and transportation platforms, which will completely revolutionize when and how we access services and entertainment, how we communicate, commute, navigate, etc., in the coming future. This paper presents an overview of the current state-of-the-art, discusses current projects, their goals, and finally highlights how emergency services and road safety will evolve with the blending of vehicular communication networks with road transportation.

CityMob: A Mobility Model Pattern Generator for VANETs

Ad hoc networking is regarded as an adequate solution to cooperative driving between communicating cars on the road. Deploying and testing these networks, usually known as Vehicular Ad-hoc Networks (VANETs), involves a high cost in the real world, and so simulation is an useful alternative in research. One of the most critical issues in a simulation study of VANETs is the use of a mobility model which resembles, as closely as possible, the real behavior of vehicular traffic. Mobility models are crucial to obtain accurate and meaningful simulation results. In this paper we present CityMob, a mobility pattern generator for VANETs. Citymob allows researchers to easily create urban mobility scenarios, including the possibility to model car accidents. We designed and developed it targeting compatibility with the ns- 2 simulator, and we implemented three different mobility models: Simple Model (SM), Manhattan Model (MM) and Downtown Model (DM). Based on a flooding alert protocol we show that the most realistic mobility model to simulate traffic accidents is the Downtown model. We also find that, for flooding to be effective, a moderate number of vehicles is required.

Improving Selfish Node Detection in MANETs Using a Collaborative Watchdog

Mobile ad-hoc networks (MANETs) are composed of mobile nodes connected by wireless links without using any pre-existent infrastructure. MANET nodes rely on network cooperation schemes to properly work, forwarding traffic unrelated to its own use. However, in the real world, most nodes may have a selfish behavior, being unwilling to forward packets for others in order to save resources. Therefore, detecting these nodes is essential for network performance. Watchdogs are used to detect selfish nodes in computer networks. A way to reduce the detection time and to improve the accuracy of watchdogs is the collaborative approach. This paper proposes a collaborative watchdog based on contact dissemination of the detected selfish nodes. Then, we introduce an analytical model to evaluate the detection time and the cost of this collaborative approach. Numerical results show that our collaborative watchdog can dramatically reduce the overall detection time with a reduced overhead.

Realistic Radio Propagation Models (RPMs) for VANET Simulations

Deploying and testing Vehicular Ad hoc Networks (VANETs) involves high cost and intensive labor. Hence simulation is a useful alternative prior to actual implementation. Most works found in the literature employ very simplistic Radio Propagation Models (RPMs), ignoring the dramatic effects presented by buildings on radio signals. In this paper, we present three different RPMs that increase the level of realism, thereby allowing us to obtain more accurate and meaningful results. These models are: (a) the Distance Attenuation Model (DAM), (b) the Building Model (BM), and (c) the Building and Distance Attenuation Model (BDAM). We evaluated these different models and compared them with the Two-ray Ground model implemented in ns-2. We then carried out further study to evaluate the impact of varying some important parameters such as vehicle density and building size on VANET warning message dissemination. Simulation results confirmed that our proposed BDAM significantly affects the percentage of blind vehicles present and the number of received warning messages, and that our models can better reflect realistic scenarios.

Road Side Unit Deployment: A Density-Based Approach

Currently, the number of vehicles increases every year, raising the probability of having accidents. When an accident occurs, wireless technologies enable vehicles to share warning messages with other vehicles by using vehicle to vehicle (V2V) communications, and with the emergency services by using vehicle to infrastructure (V2I) communications. Regarding vehicle to infrastructure communications, Road Side Units (RSUs) act similarly to wireless LAN access points, and can provide communications with the infrastructure. Since RSUs are usually very expensive to install, authorities limit their number, especially in suburbs and areas of sparse population, making RSUs a precious resource in vehicular environments. In this paper, we propose a Density-based Road Side Unit deployment policy (D-RSU), specially designed to obtain an efficient system with the lowest possible cost to alert emergency services in case of an accident. Our approach is based on deploying RSUs using an inverse proportion to the expected density of vehicles. The obtained results show how D-RSU is able to reduce the required number of RSUs, as well as the accident notification time.

Evaluating the energy-consumption reduction in a MANET by dynamically switching-off network interfaces

The design of energy-efficient routing algorithms is a fundamental problem in a mobile ad-hoc network (MANET) where battery energy is a limited resource. We evaluate a power-conserving algorithm, based on the RTS/CTS dialogue of the IEEE 802.11 standard which dynamically switches off the radio network interface card of nodes when they are neither transmitting nor receiving a packet. We evaluate the algorithm through simulations over four well-known routing algorithms: dynamic source routing (DSR), ad-hoc on demand distance vector (AODV), temporally-ordered routing algorithm (TORA), and destination-sequenced distance-vector routing (DSDV). The obtained results indicate that for all the evaluated routing protocols, the power savings are similar and range between 25 per cent and 60 per cent of the total energy.

A novel DSR-based energy-efficient routing algorithm for mobile ad-hoc networks

Mobile ad-hoc networks (MANETs) are wireless networks consisting of a collection of untethered nodes with no fixed infrastructure. An important design criterion for routing protocols in ad hoc networks is power consumption reduction. We describe an energy-efficient mechanism that can be used by a generic MANET routing protocol to prevent nodes from a sharp drop of battery power. We apply the mechanism to the dynamic source routing (DSR) and propose a novel DSR-based energy-efficient routing algorithm referred to as the energy-dependent DSR (EEDSR). We compare the EDDSR algorithm with two of the most recent proposals in this area: the least-energy aware routing (LEAR) and the minimum drain-rate (MDR) mechanism. We show that EEDSR is the best approach to reduce and balance power consumption in a wide spectrum of scenarios.