Traditionally, the vehicle has been the extension of the man's ambulatory system, docile to the driver's commands. Recent advances in communications, controls and embedded systems have changed this model, paving the way to the Intelligent Vehicle Grid. The car is now a formidable sensor platform, absorbing information from the environment (and from other cars) and feeding it to drivers and infrastructure to assist in safe navigation, pollution control and traffic management. The next step in this evolution is just around the corner: the Internet of Autonomous Vehicles. Pioneered by the Google car, the Internet of Vehicles will be a distributed transport fabric capable to make its own decisions about driving customers to their destinations. Like other important instantiations of the Internet of Things (e.g., the smart building), the Internet of Vehicles will have communications, storage, intelligence, and learning capabilities to anticipate the customers' intentions. The concept that will help transition to the Internet of Vehicles is the Vehicular Cloud, the equivalent of Internet cloud for vehicles, providing all the services required by the autonomous vehicles. In this article, we discuss the evolution from Intelligent Vehicle Grid to Autonomous, Internet-connected Vehicles, and Vehicular Cloud.

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Internet of vehicles: From intelligent grid to autonomous cars and vehicular clouds

Underwater wireless sensor networks (UWSNs) have been showed as a promising technology to monitor and explore the oceans in lieu of traditional undersea wireline instruments. Nevertheless, the data gathering of UWSNs is still severely limited because of the acoustic channel communication characteristics. One way to improve the data collection in UWSNs is through the design of routing protocols considering the unique characteristics of the underwater acoustic communication and the highly dynamic network topology. In this paper, we propose the GEDAR routing protocol for UWSNs. GEDAR is an anycast, geographic and opportunistic routing protocol that routes data packets from sensor nodes to multiple sonobuoys (sinks) at the sea's surface. When the node is in a communication void region, GEDAR switches to the recovery mode procedure which is based on topology control through the depth adjustment of the void nodes, instead of the traditional approaches using control messages to discover and maintain routing paths along void regions. Simulation results show that GEDAR significantly improves the network performance when compared with the baseline solutions, even in hard and difficult mobile scenarios of very sparse and very dense networks and for high network traffic loads.

Geographic and Opportunistic Routing for Underwater Sensor Networks

The great advances made in the wireless technology have enabled the deployment of wireless communication networks in some of the harshest environments such as volcanoes, hurricane-affected regions, and underground mines. In such challenging environments suffering from the lack of infrastructure, traditional routing is not efficient and sometimes not even feasible. Moreover, the exponential growth of the number of wireless connected devices has created the need for a new routing paradigm that could benefit from the potentials offered by these heterogeneous wireless devices. Hence, in order to overcome the traditional routing limitations, and to increase the capacity of current dynamic heterogeneous wireless networks, the opportunistic routing paradigm has been proposed and developed in recent research works. Motivated by the great interest that has been attributed to this new paradigm within the last decade, we provide a comprehensive survey of the existing literature related to opportunistic routing. We first study the main design building blocks of opportunistic routing. Then, we provide a taxonomy for opportunistic routing proposals, based on their routing objectives as well as the optimization tools and approaches used in the routing design. Hence, five opportunistic routing classes are defined and studied in this paper, namely, geographic opportunistic routing, link-state-aware opportunistic routing, probabilistic opportunistic routing, optimization-based opportunistic routing, and cross-layer opportunistic routing. We also review the main protocols proposed in the literature for each class. Finally, we identify and discuss the main future research directions related to the opportunistic routing design, optimization, and deployment.

A Survey on Opportunistic Routing in Wireless Communication Networks

Underwater Wireless Sensor Networks (UWSNs) contain several components such as vehicles and sensors that are deployed in a specific acoustic area to perform collaborative monitoring and data collection tasks. These networks are used interactively between different nodes and ground-based stations. Presently, UWSNs face issues and challenges regarding limited bandwidth, high propagation delay, 3D topology, media access control, routing, resource utilization, and power constraints. In the last few decades, research community provided different methodologies to overcome these issues and challenges; however, some of them are still open for research due to variable characteristics of underwater environment. In this paper, a survey of UWSN regarding underwater communication channel, environmental factors, localization, media access control, routing protocols, and effect of packet size on communication is conducted. We compared presently available methodologies and discussed their pros and cons to highlight new directions of research for further improvement in underwater sensor networks.

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Underwater Wireless Sensor Networks: A Review of Recent Issues and Challenges

This chapter contains sections titled: Introduction Communication Architecture Basics of Underwater Communications Physical Layer Medium Access Control Layer Network Layer Cross-Layer Design Experimental Platforms UW-Buffalo: An Underwater Acoustic Testbed at the University at Buffalo Conclusions References

https://www.eng.buffalo.edu/wnesl/papers/Wiley_AdvancesUWAN_2013.pdf

Advances in Underwater Acoustic Networking

Underwater mobile sensor networks have recently been proposed as a way to explore and observe the ocean, providing 4D (space and time) monitoring of underwater environments. We consider a specialized geographic routing problem called pressure routing that directs a packet to any sonobuoy on the surface based on depth information available from on-board pressure gauges. The main challenge of pressure routing in sparse underwater networks has been the efficient handling of 3D voids. In this respect, it was recently proven that the greedy stateless perimeter routing method, very popular in 2D networks, cannot be extended to void recovery in 3D networks. Available heuristics for 3D void recovery require expensive flooding. In this paper, we propose a Void-Aware Pressure Routing (VAPR) protocol that uses sequence number, hop count and depth information embedded in periodic beacons to set up next-hop direction and to build a directional trail to the closest sonobuoy. Using this trail, opportunistic directional forwarding can be efficiently performed even in the presence of voids. The contribution of this paper is twofold: a robust soft-state routing protocol that supports opportunistic directional forwarding; and a new framework to attain loop freedom in static and mobile underwater networks to guarantee packet delivery. Extensive simulation results show that VAPR outperforms existing solutions.

/pdf/vapr-void-aware-pressure-routing-for-underwater-sensor-xzms64rz0x.pdf

VAPR: Void-Aware Pressure Routing for Underwater Sensor Networks

In the drive-thru Internet access systems, vehicles connect to road-side access points (APs) to use IP-based services, such as web-browsing, e-mail, and file download, in addition to the customized vehicular applications. However, the mobility of vehicles and the limited coverage of APs result in the short connectivity duration and low throughput, thus leading to low availability of Internet to vehicle services. Vehicle-to-vehicle (V2V) relay support is an attractive backup solution that can address these limitations by extending the coverage. To fully realize the benefit of V2V relay support, however, the vehicle that gives the best performance must be selected as relay, yet the dynamic wireless channel conditions and the high speed of vehicles render relay selection a challenging problem. In this paper, we evaluate several relay strategies in an analytic framework to compute the resulting overall network capacity with fading channels. We then propose and devise an efficient opportunistic relay protocol that exploits multiuser diversity and effectively copes with the dynamic channel. Through both capacity analysis and Qualnet simulations, we show that the opportunistic relay scheme significantly outperforms others.

An opportunistic relay protocol for vehicular road-side access with fading channels

Recent advances in wireless technology have led to the proliferation of wireless devices, ranging from wireless LAN to cellular phones. There has been, and will be, an increase in not only the number of wireless services, but also the number of types of wireless services, and greater demand for mobility, portability, and integrated services. For wireless success to continue, technologies must support a high degree of flexibility and interoperability of wireless devices to scale with such demand. Next Generation Wireless will depend highly upon flexible and interoperable devices in constructing a wireless network that consists of heterogeneous devices that can communicate with each other. Our work investigates the technical issues that must be overcome in bringing such flexibility and interoperability, one of which being device discovery. We propose Wireless Interrupt, an inter- device signaling mechanism that can be employed by software defined radios, such that a device can signal its neighbors of its existence or the services it provides without knowing the protocols or channels used by its neighbors a priori.

Wireless Interrupt: Inter-Device Signaling in Next Generation Wireless Networks

In this paper, we consider the use of unlicensed Wi-Fi band for vehicular ad hoc networks. In particular, we focus on exploiting channelization to improve spatial reuse, and avoiding interference that is external to the vehicular network. To this end, we propose Cognitive Channel Hopping (CCH), a decentralized channel hopping protocol where nodes select their channels based on cognitively collected channel quality measurements, in a manner that the network's connectivity is maintained. Our evaluation shows that CCH can take advantage of multiple channels that are available to significantly improve the network performance over a single-channel network, and can effectively tolerate external interference.

http://netlab.cs.ucla.edu/wiki/files/cch.pdf

CCH: Cognitive Channel Hopping in Vehicular Ad Hoc Networks

The deployment of wireless multicast in vehicular networks using the ISM band is challenging due to the interference from residential WiFi users. Recently developed cognitive radio techniques can help overcome such interference, with spectrum sensing and multi-channel assignment. CoCast is a cognitive multi-channel multicast protocol originally designed for the urban environment under the assumption that channels are orthogonal. In fact, Wi-Fi channels in the 2.4-GHz ISM band are partially overlapped. In this paper, we remodel the CoCast protocol to handle the more realistic environment where channels are overlapped in frequency. The main challenge is the adjacent channel interference, the effect of which is mitigated in CoCast by employing two techniques: 1) parallel frame transmission over OFDM subchannels, and 2) network coding. Our evaluation shows that the reliability of multicast communication among vehicles in a dense urban environment can be significantly improved with these protocol extensions.

Brian Sung Chul Choi

Papers

VAPR: Void-Aware Pressure Routing for Underwater Sensor Networks

An opportunistic relay protocol for vehicular road-side access with fading channels

Wireless Interrupt: Inter-Device Signaling in Next Generation Wireless Networks

CCH: Cognitive Channel Hopping in Vehicular Ad Hoc Networks

Cognitive multicast (CoCast) in vehicular networks using OFDM subchannels and network coding