Angle-Aware Greedy Forwarding Algorithm for Vehicular Ad Hoc Networks

Greedy Perimeter Stateless Routing (GPSR) gives the good forwarding nodes for Mobile Ad Hoc Networks (MANET) but does not provide the right directional forwarding nodes in Vehicular Ad Hoc Network (VANET). This is the fact that MANET uses the nodes without limitations in moving but VANET uses fixed infrastructure in mobility such as roads with lanes. The key of original greedy forwarding is choosing the forwarding node with the shortest distance between the source and the destination. It does not consider the direction of the forwarding nodes, which possibly cause the selected forwarding node going opposite direction from the destination. This paper thus tries to improve the greedy forwarding method of Greedy Perimeter Stateless Routing (GPSR) by taking into considerations in both the distance and the direction. Moreover it shows the mystery of angle that gives the right direction. The optimized GPSR (OGPSR) using improved greedy forwarding provides the better throughput, average end-to-end delay and routing overheads than the original GPSR

MODIFIKASI METODE PEMILIHAN FORWARDING NODE BERDASARKAN FAKTOR ARAH DAN KECEPATAN KENDARAAN PADA PROTOKOL ROUTING GPSR DALAM LINGKUNGAN VANETS

VANETs (Vehicular ad hoc networks) merupakan teknologi yang digunakan untuk komunikasi antar kendaraan. Dalam VANETs, kendaraan bergerak dengan kecepatan tinggi dan arah yang berbeda-beda, sehingga menyebabkan jaringan komunikasi yang telah terbentuk berubah dengan cepat. Salah satu contoh protokol routing yang sering digunakan dalam komunikasi VANETs adalah GPSR. Greedy perimeter stateless routing (GPSR), routing protokol baru untuk jaringan nirkabel yang menggunakan informasi posisi node tujuan untuk membuat keputusan penerusan paket. Topologi jaringan VANETs yang sangat dinamis menyebabkan komunikasi antar node tidak stabil. Node next hop yang telah dipilih mungkin telah keluar dari jangkauan transmisi sebelum menerima paket. Penelitian ini bertujuan untuk memecahkan masalah dalam protokol routing GPSR terkait ketidakstabilan komunikasi karena posisi node yang berubah dalam mode greedy forwarding. Dalam penelitian ini penulis menambahkan set parameter yang digunakan untuk mengambil keputusan routing dengan memasukkan faktor kecepatan dan arah pergerakan kendaraan. Setiap node akan melakukan penghitungan rata-rata geometrik kecepatannya sebelum penyiaran beacon message. Informasi rata-rata geometrik tersebut akan ditambahkan pada beacon message. Setelah node menerima paket beacon message, node akan memperbarui informasi yang terdapat pada neighbor table. Pada penelitian ini, neighbor table juga menyimpan informasi posisi node pada waktu sebelumnya dan informasi rata-rata geometrik kecepatan. Informasi dalam neighbor table tersebut akan digunakan dalam pengambilan keputusan routing. Penelitian ini juga melakukan modifikasi pada metode penerusan paket greedy forwarding. Jika penerusan paket menggunakan metode greedy forwarding, tahapan pertama yang dilakukan adalah menemukan node-node yang berada dalam area komunikasi optimum. Selanjutnya dari node-node yang berada pada area komunikasi optimum, akan dilakukan seleksi pemilihan forwarding node. Node yang layak menjadi forwarding node adalah node yang paling minimal perbedaan rata-rata geometrik kecepatannya dan bergerak mendekati node tujuan. Diharapkan dengan penelitian ini dapat meningkatkan performa protokol routing GPS

Persistent Localized Broadcasting in VANETs

We present a communication protocol, called LINGER, for persistent dissemination of delay-tolerant information to vehicular users, within a geographical area of interest. The goal of LINGER is to dispatch and confine information in localized areas of a mobile network with minimal protocol overhead and without requiring knowledge of the vehicles' routes or destinations. LINGER does not require roadside infrastructure support: it selects mobile nodes in a distributed, cooperative way and lets them act as "information bearers", providing uninterrupted information availability within a desired region. We analyze the performance of our dissemination mechanism through extensive simulations, in complex vehicular scenarios with realistic node mobility. The results demonstrate that LINGER represents a viable, appealing alternative to infrastructure-based solutions, as it can successfully drive the information toward a region of interest from a far away source and keep it local with negligible overhead. We show the effectiveness of such an approach in the support of localized broadcasting, in terms of both percentage of informed vehicles and information delivery delay, and we compare its performance to that of a dedicated, state-of-the-art protoco

Enhanced GPSR Routing in Multi-Hop Vehicular Communications through Movement Awareness

Abstract-Providing reliable and efficient routing in presence of relative movement motivates the introduction of movement awareness to improve performance of existing position-based routing schemes in vehicular ad-hoc networks. The proposed algorithm represents a modification of well-known GPSR which exploits information about movement in order to improve the next forwarding node decision. Performance evaluation of the proposed protocol underlines a promising and robust basis for designing a routing strategy suitable for the automotive scenario

THE IMPROVEMENT OF FORWARDING NODE SELECTION METHOD BASED ON SPEED AND DISTANCE FACTOR ON GREEDY PERIMETER STATELESS ROUTING PROTOCOL IN VANETS ENVIRONMENT

VANETs (Vehicular ad hoc networks) are technologies used for communication between vehicles. In VANETs, vehicles move at high speeds and in different directions, causing the communication network that has formed to change rapidly. One example of a routing protocol that is often used in VANET communication is GPSR. Greedy perimeter stateless routing (GPSR), a new routing protocol for wireless networks that uses the position information of the destination node to make packet forwarding decisions. Because the VANETs topology is very dynamic, the next hop node that has been selected may be out of transmission range before receiving a packet. This study aims to solve problems in the GPSR routing protocol related to communication instability because the position of the node changes in greedy forwarding mode. In this study the authors add a set of parameters used to make routing decisions by entering the speed and direction of vehicle movement factors. Nodes that deserve to be forwarding nodes are nodes that have the least minimal geometric difference in speed and move toward the destination node. Based on the trials that have been carried out, in the GPSR grid scenario with an average speed compared to the original GPSR, the biggest increase in PDR is 50.05%, the biggest decrease in E2D is 1.91 ms. On the real map in the GPSR protocol road environment with an average speed compared to the original GPSR, the largest PDR increase was 17.26%, while the E2D value increased / decreased less than 1 ms and in the node 90 scenario, E2D decreased by 0, 27 ms. On the real map in a residential neighborhood, the biggest increase in PDR was 31.79%. The E2D value experienced the largest decrease of 0.43 ms. While the value of routing overhead, between the original GPSR and GPSR with an average speed does not show a significant difference

Contribution to the design of VANET routing protocols for realistic urban environments

One of the main concerns of the cities' administration is mobility management. In Intelligent Transportation Systems (ITS), pedestrians, vehicles and public transportation systems could share information and react to any situation in the city. The information sensed by vehicles could be useful for other vehicles and for the mobility authorities. Vehicular Ad hoc Networks (VANETs) make possible the communication between vehicles (V2I) and also between vehicles and fixed infrastructure (V2I) managed by the city's authorities. In addition, VANET routing protocols minimize the use of fixed infrastructure since they employ multi-hop V2V communication to reach reporting access points of the city. This thesis aims to contribute in the design of VANET routing protocols to enable reporting services (e.g., vehicular traffic notifications) in urban environments. The first step to achieve this global objective has been the study of components and tools to mimic a realistic VANET scenario. Moreover, we have analyzed the impact of the realism of each one of those components in the simulation results. Then, we have improved the Address Resolution procedure in VANETs by including it in the routing signaling messages. Our approach simplifies the VANET operation and increases the packet delivery ratio as consequence. Afterwards, we have tackled the issue of having duplicate packets in unicast communications and we have proposed routing filters to lower their presence. This way we have been able to increase the available bandwidth and reduce the average packet delay with a slight increase of the packet losses. Besides, we have proposed a Multi-Metric Map aware routing protocol (MMMR) that incorporates four routing metrics (distance, trajectory, vehicle density and available bandwidth) to take the forwarding decisions. With the aim of increasing the number of delivered packets in MMMR, we have developed a Geographical Heuristic Routing (GHR) algorithm. GHR integrates Tabu and Simulated Annealing heuristic optimization techniques to adapt its behavior to the specific scenario characteristics. GHR is generic because it could use any geographical routing protocol to take the forwarding decisions. Additionally, we have designed an easy to implement forwarding strategy based on an extended topology information area of two hops, called 2-hops Geographical Anycast Routing (2hGAR) protocol. Results show that controlled randomness introduced by GHR improves the default operation of MMMR. On the other hand, 2hGAR presents lower delays than GHR and higher packet delivery ratio, especially in high density scenarios. Finally, we have proposed two mixed (integer and linear) optimization models to detect the best positions in the city to locate the Road Side Units (RSUs) which are in charge of gathering all the reporting information generated by vehicles.Una de las principales preocupaciones en la administración de las ciudades es la gestión de la movilidad de sus vehículos, debido a los problemas de tráfico como atascos y accidentes. En los sistemas inteligentes de transporte (SIT), peatones, vehículos y transporte público podrán compartir información y adaptarse a cualquier situación que suceda en la ciudad. La información obtenida por los sensores de los vehículos puede ser útil para otros vehículos y para las autoridades de movilidad. Las redes ad hoc vehiculares (VANETs) hacen posible la comunicación entre los propios vehículos (V2V) y entre vehículos y la infraestructura fija de la red de la ciudad (V2I). Asimismo, los protocolos de encaminamiento para redes vehiculares minimizan el uso de infraestructura fija de red, ya que los protocolos de encaminamiento VANET emplean comunicaciones multisalto entre vehículos para encaminar los mensajes hasta los puntos de acceso de la red en la ciudad. El objetivo de esta tesis doctoral es contribuir en el diseño de protocolos de encaminamiento en redes ad hoc vehiculares para servicios de notificaciones (p.ej. reportes del estado del tráfico) en entornos urbanos. El primer paso para alcanzar este objetivo general ha sido el estudio de componentes y herramientas para simular un escenario realista de red ad hoc vehicular. Además, se ha analizado el impacto del nivel de realismo de cada uno de los componentes de simulación en los resultados obtenidos. Así también, se ha propuesto un mecanismo de resolución de direcciones automático y coherente para redes VANET a través del uso de los propios mensajes de señalización de los protocolos de encaminamiento. Esta mejora simplifica la operación de una red ad hoc vehicular y como consecuencia aumenta la tasa de recepción de paquetes. A continuación, se ha abordado el problema de la aparición inesperada de paquetes de datos duplicados en una comunicación punto a punto. Para ello, se ha propuesto el filtrado de paquetes duplicados a nivel del protocolo de encaminamiento. Esto ha producido un incremento del ancho disponible en el canal y una reducción del retardo medio en la trasmisión de un paquete, a costa de un mínimo aumento de la pérdida de paquetes. Por otra parte, hemos propuesto un protocolo de encaminamiento multi-métrica MMMR (Multi-Metric Map-aware Routing protocol), el cual incorpora cuatro métricas (distancia al destino, trayectoria, densidad de vehículos y ancho de banda) en las decisiones de encaminamiento. Con el objetivo de aumentar la tasa de entrega de paquetes en MMMR, hemos desarrollado un algoritmo heurístico de encaminamiento geográfico denominado GHR (Geographical Heuristic Routing). Esta propuesta integra las técnicas de optimización Tabu y Simulated Annealing, que permiten a GHR adaptarse a las características específicas del escenario. Adicionalmente, hemos propuesto 2hGAR (2-hops Geographical Anycast Routing), un protocolo de encaminamiento anycast que emplea información de la topología de red a dos saltos de distancia para tomar la decisión de encaminamiento de los mensajes. Los resultados muestran que la aleatoriedad controlada de GHR en su operación mejora el rendimiento de MMMR. Asimismo, 2hGAR presenta retardos de paquete menores a los obtenidos por GHR y una mayor tasa de paquetes entregados, especialmente en escenarios con alta densidad de vehículos. Finalmente, se han propuesto dos modelos de optimización mixtos (enteros y lineales) para detectar los mejores lugares de la ciudad donde ubicar los puntos de acceso de la red, los cuales se encargan de recolectar los reportes generados por los vehículos.Postprint (published version