Seyed Mehdi Iranmanesh

Robustness of cooperative forward collision warning systems to communication uncertainty

Cooperative collision avoidance systems rely on communication between vehicles to detect possibility of collision. In this paper, we present a systematic approach to study the performance of emerging communication based vehicle safety systems. Examples of such systems include forward collision warning (FCW) application. We employ a co-simulation tool that we have developed jointly in collaboration with industry partners for this purpose. The tool allows joint study of the safety application and its underlying communication system. We utilize this tool and study the impact of communication uncertainties on a new variation of the FCW algorithm that has been designed by the team. In this paper, the impact of communication loss and the choice of signal communication logic are examined. It is shown that the relationship between communication loss and accuracy of hazard detection algorithm is non-linear. It is also shown that employing error-dependent communication logic will yield considerable gains in communication or accuracy of tracking and hazard detection. Network awareness in communication logic is also demonstrated to be beneficial in high communication loss situations.

Polar coding for achieving the capacity of marginal channels in nonbinary-input setting

Achieving information-theoretic security using explicit coding scheme in which unlimited computational power for eavesdropper is assumed, is one of the main topics is security consideration. It is shown that polar codes are capacity achieving codes and have a low complexity in encoding and decoding. It has been proven that polar codes reach to secrecy capacity in the binary-input wiretap channels in symmetric settings for which the wiretappers channel is degraded with respect to the main channel. The first task of this paper is to propose a coding scheme to achieve secrecy capacity in asymmetric nonbinary-input channels while keeping reliability and security conditions satisfied. Our assumption is that the wiretap channel is stochastically degraded with respect to the main channel and message distribution is unspecified. The main idea is to send information set over good channels for Bob and bad channels for Eve and send random symbols for channels that are good for both. In this scheme the frozen vector is defined over all possible choices using polar codes ensemble concept. We proved that there exists a frozen vector for which the coding scheme satisfies reliability and security conditions. It is further shown that uniform distribution of the message is the necessary condition for achieving secrecy capacity.