Secure V2V communications: Performance impact of computational overheads

Safety applications aim to avoid vehicular accidents, by providing advisories to the driver, by using secure broadcast vehicle-to-vehicle (V2V) communications. However, any security mechanism used for authenticating broadcast V2V messages, comes with overheads in terms of computation, storage and communications. Further due to the resource-constrained computing platforms used in the automotive domain, these overheads could translate into performance bottlenecks. Prior works related to performance modeling of secure V2V communications do not consider the computational overheads of security, since traditionally packet transmission rather than packet processing is taken to be the bottleneck. This paper provides an evaluation of the performance of secure V2V communications, while explicitly modeling the computational and storage overheads due to security. We observe that there is a complex coupling between the security and the communication layers, and that the performance bottlenecks could shift from one to the other depending on the system parameters. In order to explain these observations, we propose a fixed point based approach which essentially assumes the two layers at a given node independent from each other and from those at other nodes, and uses the inherent consistency relationships to yield fixed point equations for performance metrics such as blocking or collision probability. Our results indicate that this is a promising approach which works quite accurately.