Infocast: A New Paradigm for Collaborative Content Distribution from Roadside Units to Vehicular Networks Using Rateless Codes

In this paper, we address the problem of distributing a large amount of bulk data to a sparse vehicular network from roadside infostations, using efficient vehicle-to-vehicle collaboration. Due to the highly dynamic nature of the underlying vehicular network topology, we depart from architectures requiring centralized coordination, reliable MAC scheduling, or global network state knowledge, and instead adopt a distributed paradigm with simple protocols. In other words, we investigate the problem of reliable dissemination from multiple sources when each node in the network shares a limited amount of its resources for cooperating with others. By using \emph{rateless} coding at the Road Side Unit (RSU) and using vehicles as data carriers, we describe an efficient way to achieve reliable dissemination to all nodes (even disconnected clusters in the network). In the nutshell, we explore vehicles as mobile storage devices. We then develop a method to keep the density of the rateless codes packets as a function of distance from the RSU at the desired level set for the target decoding distance. We investigate various tradeoffs involving buffer size, maximum capacity, and the mobility parameter of the vehicles

FRESH-DFE: A New Structure for Interference Cancellation

This paper proposes a new structure of decision feedback equalizer that exploits the cyclostationary properties of digitally modulated signals to mitigate interference. In the proposed structure, the forward filter of the conventional DFE is replaced by a cyclic filter. It is assumed that the desired and the interference signals use some mutually different signaling attributes, for example symbol rates, centre frequency etc. The resulting structure is evaluated in the presence of up to six strong interfering signals, a scenario that is typically found in wireless cellular systems. The proposed structure provides performance gains for some modulation formats but it reduces to the conventional DFE for other signal formats

FRESH-DFE: A New Structure for Interference Cancellation

This paper proposes a new structure of decision feedback equalizer that exploits the cyclostationary properties of digitally modulated signals to mitigate interference. In the proposed structure, the forward filter of the conventional DFE is replaced by a cyclic filter. It is assumed that the desired and the interference signals use some mutually different signaling attributes, for example symbol rates, centre frequency etc. The resulting structure is evaluated in the presence of up to six strong interfering signals, a scenario that is typically found in wireless cellular systems. The proposed structure provides performance gains for some modulation formats but it reduces to the conventional DFE for other signal formats

A Structure for Fast Data Encryption

Abstract Fast Data Encryption (FDE) is a new symmetric block cipher which has a DES-like structure. FDE has been designed with an increased key length, increased key scheduling complexity and an improved round function which can be executed in parallel. FDE uses eight Substitution Boxes (S-boxes) in the round function to provide confusion. In this paper, we present the FDE structure and an algorithm to construct a set of strong S-boxes. Eight suitable S-boxes from this set are suggested for use with FDE. Mathematics Subject Classification: 94A6

A reliable geocast routing protocol for Vehicular Ad Hoc Networks

In addition to safety applications, new Vehicular Ad-Hoc Network (VANET) applications such as onboard entertainment and traffic management are rapidly being developed. This has made geocast, i.e. the transmission of data over a geographic area, an important research topic. Often geocast is done over wide and distant areas, which can result in significant overhead. In this paper, existing VANET routing protocols are investigated from a geocast perspective. To address the shortcomings of these methods in addressing both overhead and packet delivery ratio issues in geocast routing, two enhanced mechanisms are introduced based on the AODV routing protocol. Unicast routing is employed in the proposed protocols to transmit data to the destination region, and then flooding is used within the region for data dissemination. Furthermore, rateless coding and link layer notifications are used to improve the delivery ratio. The proposed methods are compared with existing flooding based geocast routing and Inter Vehicle Geocast (IVG) routing. Results are presented for an urban environment in terms of delay, overhead, and message delivery. These results show that the proposed approach significantly reduces the overhead and increases the delivery ratio with a minimal increase in delay