Cars as Roadside Units: A Self-Organizing Network Solution

<p>Deploying roadside units, RSUs, for increasing the connectivity of vehicular ad hoc networks is deemed necessary for coping with the partial penetration of DSRC radios into the market in the initial stages of DSRC deployment. Several factors, including cost, complexity, existing systems, and lack of cooperation between government and private sectors, have impeded the deployment of RSUs. In this article, we propose to solve this formidable problem by using a biologically inspired self-organizing network approach whereby certain vehicles serve as RSUs. The proposed solution is based on designing local rules and the corresponding algorithms that implement them. Results show that the proposed approach can increase the message reachability and connectivity substantially.</p

Geometry-Based Vehicle-to-Vehicle Channel Modeling for Large-Scale Simulation

<p>Due to the dynamic nature of vehicular traffic and the road surroundings, vehicle-to-vehicle (V2V) propagation characteristics vary greatly on both small and large scale. Recent measurements have shown that both large static objects (e.g., buildings and foliage) and mobile objects (surrounding vehicles) have a profound impact on V2V communication. At the same time, system-level vehicular ad hoc network (VANET) simulators by and large employ simple statistical propagation models, which do not account for surrounding objects explicitly. We designed Geometry-based Efficient propagationModel for V2V communication (GEMV2), which uses outlines of vehicles, buildings, and foliage todistinguish the following three types of links: line of sight (LOS), non-LOS (NLOS) due to vehicles, and NLOS due to static objects. For each link, GEMV² calculates the large-scale signal variations deterministically, whereas the small-scale signal variations are calculated stochastically based on the number and size of surrounding objects. We implement GEMV² in MATLAB and show that it scales well by using it to simulate radio propagation for city-wide networks with tens of thousands of vehicles on commodity hardware. We make the source code of GEMV² freely available. Finally, we validate GEMV² against extensive measurements performed in urban, suburban, highway, and open-space environments.</p

Accelerating the Adoption of Virtual Traffic Lights through Policy Decisions

A new technology known as Virtual Traffic Lights (VTL) was recently proposed as a self-organizing new paradigm for traffic management. This new technology uses the vehicle-to-vehicle (V2V) communications as its premise. VTL can revolutionize traffic management in urban areas as it can substantially reduce commute time of urban workers, increase productivity, and lead to a greener environment. In a VTL environment, vehicles self-organize to elect a leader which serves as a virtualtraffic light to decide the right of way at that intersection, thus replacing the current physical traffic lights. Implementing VTL technology with partial penetration, however, is an outstanding issue that needs to be addressed. This paper addresses this issue by proposing a co-existence model whereby VTL equipped vehicles can co-exist with vehicles that do not have VTL. Simulation results show that the transition model proposed here could provide drivers with strong incentives to adopt the VTL technology.</p

Grouping of RFID Tags via Strongly Selective Families

This letter proposes a novel scheme for grouping of radio-frequency identification (RFID) tags, based on strongly selective families (SSFs). Grouping of RFID tags allows verifying the integrity of groups of objects without external systems such as databases or verifiers, and can be extended to identify missing objects. The existing scheme is based on Gallager's low-density parity-check (LDPC) codes and, as such, it cannot easily achieve designated decoding guarantees due to its pseudo-random nature. Motivated by the strongly selective property of SSFs, this study proposes grouping of RFID tags via SSFs, such that designated decoding guarantees are more easily achieved. Simulation and theoretical results are presented, demonstrating that the proposed scheme can greatly improve the performance of the existing one.</p

Inter-Vehicle Communication – Quo Vadis

<p>In September 2013, leading experts in intervehicle communication from all over the world met at the renowned Dagstuhl Castle for a seminar discussing the question "Inter-Vehicular Communication - Quo Vadis?" The objective was to identify the current state of the art and, more important, the open challenges in R&D from both a scientific and an industrial point of view. After more than a decade of research on vehicular networks, the experts very seriously asked whether additional research in this field is necessary and, if so, which will be the most intriguing and innovative research directions. It turned out that the overall perspective has changed in the last few years, mainly as a result of the ongoing field operational tests in the United States and Europe. In this article, we report the key outcomes and results from the discussions, pointing to new research directions and new challenges that need to be met for a second generation of vehicular networking applications and protocols. In particular, we present the reports and findings from the four working groups on scientific foundations of vehicular networking, field operational tests, IVC applications, and heterogeneous vehicular networks.</p

Deploying Road Side Units in Sparse Vehicular Networks: What Really Works and What Does Not

<p>The 802.11p/WAVE standard relies on the presence of onboard units (OBUs) and roadside units(RSUs) for communications in vehicular networks. In this paper, we study the benefits of deployingRSUs to improve communications in highway scenarios. We develop an analytical model to analyze communication delay in a highway scenario with bidirectional traffic, considering both connected and disconnected RSUs, and validate our model via simulations and experimental measurements with 802.11p equipment. Contrary to conventional wisdom, our results show that significant benefits of RSUs in terms of connectivity and message dissemination can only be achieved when the deployedRSUs are interconnected. Conversely, deploying a large number of disconnected RSUs will lead to little or no benefit in message dissemination delay.</p