On the Design and Analysis of Consensus Protocols for Vehicular Ad Hoc Networks
Doktorsavhandling, 2017

Vehicle-to-vehicle communication technologies support diverse cooperative applications for intelligent transportation systems to increase safety and fuel efficiency of road vehicles. Vehicles participating in a cooperative pplication are expected to make coordinated and mutually consistent decisions. To ensure consistency, it is often essential that the participating vehicles reach agreement on the data they use as a basis for these decisions. This thesis deals with the fundamental problem of reaching agreement on a value, or a set of values, in a distributed system in the presence of unrestricted communication failures. It is known from the literature that this problem is impossible to solve perfectly, i.e., no matter what algorithm we use there is always a non-zero probability of disagreement. Hence, our aim is to design algorithms that minimize the probability of disagreement. We propose and analyse several agreement algorithms to solve three fundamental consensus problems. These algorithms are distinguished by their decision criterion, which determine whether a computer should decide on a value or decide to abort. Our analyses show that the probability of disagreement depends strongly on the number of computers in the system, the number of rounds of message exchange, the choice of decision criterion, as well as the probability of message loss. We identify two types of disagreement, safe and unsafe disagreement, and show that unsafe disagreement can be avoided if all computers know the number of computers in the system.

Vehicular Ad-Hoc Networks

Intelligent Transportation Systems

Probabilistic Analysis

Communication Failure

Agreement Algorithms

Consensus

EB, Hörsalsvägen 11, Chalmers
Opponent: Mohamed Kaaniche, Head of the Dependable Computing and Fault Tolerance research group at LAAS-CNRS, FRANCE

Författare

Negin Fathollah Nejad Asl

Chalmers, Data- och informationsteknik, Datorteknik

Negin Fathollahnejad, Raul Barbosa, Johan Karlsson, "A Probabilistic Analysis of a Leader Election Protocol for Virtual Traffic Lights", in the 22nd IEEE Pacific Rim International Symposium on Dependable Computing (PRDC), pp. 311-320, Christchurch, New Zealand, 22-25 January, 2017.

Negin Fathollahnejad, Risat Pathan, Johan Karlsson,"On the Probability of Unsafe Disagreement in Group Formation Algorithms for Vehicular Ad hoc Networks", in the 11th European Dependable Computing Conference (EDCC), Paris, France, September 7-11, 2015.

Negin Fathollahnejad, Emilia Villani, Risat Pathan, Raul Barbosa, Johan Karlsson,"On probabilistic analysis of disagreement in synchronous consensus protocols", in the 10th European Dependable Computing Conference (EDCC), Newcastle, UK, May 13-16, 2014.

Negin Fathollahnejad, Emilia Villani, Risat Pathan, Raul Barbosa, Johan Karlsson, "Probabilistic analysis of a 1-of-n selection algorithm using a moderately pessimistic decision criterion", in the 19th IEEE Pacific Rim International Symposium on Dependable Computing (PRDC), Vancouver, Canada 2-4 December, 2013.

Emilia Villani, Negin Fathollahnejad, Risat Pathan, Raul Barbosa, Johan Karlsson, "Reliability Analysis of Consensus in Cooperative Transport Systems" in Proceedings of the 2nd Workshop on Architecting Safety in Collaborative Mobile Systems (ASCoMS), September 2013, Toulouse, France.

Negin Fathollahnejad, Emilia Villani, Risat Pathan, Raul Barbosa, Johan Karlsson, "On Reliability Analysis of Leader Election Protocols for Virtual Traffic Lights", in 43rd Annual IEEE/IFIP Conference on Dependable Systems and Networks Workshop (DSNW), pp. 1-12, Budapest, Hungry, 24-27 June, 2013.

Ämneskategorier

Inbäddad systemteknik

Datavetenskap (datalogi)

Datorsystem

ISBN

978-91-7597-619-8

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4300

Utgivare

Chalmers tekniska högskola

EB, Hörsalsvägen 11, Chalmers

Opponent: Mohamed Kaaniche, Head of the Dependable Computing and Fault Tolerance research group at LAAS-CNRS, FRANCE