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About this book

This brief examines current research on improving Vehicular Networks (VANETs), examining spectrum scarcity due to the dramatic growth of mobile data traffic and the limited bandwidth of dedicated vehicular communication bands and the use of opportunistic spectrum bands to mitigate congestion. It reviews existing literature on the use of opportunistic spectrum bands for VANETs, including licensed and unlicensed spectrum bands and a variety of related technologies, such as cognitive radio, WiFi and device-to-device communications. Focused on analyzing spectrum characteristics, designing efficient spectrum exploitation schemes, and evaluating the date delivery performance when utilizing different opportunistic spectrum bands, the results presented in this brief provide valuable insights on improving the design and deployment of future VANETs.

Table of Contents

Frontmatter

Chapter 1. Introduction

Abstract
Vehicular networks play a critical role in both developing the intelligent transportation system and providing data services to vehicular users (VUs) by incorporating wireless communication and informatics technologies into the transportation system. However, due to the dramatic growth of mobile data traffic and the limited bandwidth of dedicated vehicular communication band, vehicular networks are facing spectrum scarcity problem in which spectrum resource is not sufficient to satisfy the data requirements, and thus the performance is compromised. In this chapter, we first overview the vehicular networks, and then describe the spectrum scarcity problem in vehicular networks, including the causes, and the impacts of the problem on the performance of vehicular networks. At last, the aim of the monograph is provided.
Nan Cheng, Xuemin (Sherman) Shen

Chapter 2. Opportunistic Communication Spectra Utilization

Abstract
The objective of the monograph is to utilize the opportunistic spectra for VANETs through technologies such as CR, WiFi, and D2D communications. This chapter introduces the background and surveys the literature of these technologies, focusing on research works related to VANETs.
Nan Cheng, Xuemin (Sherman) Shen

Chapter 3. Opportunistic Spectrum Access Through Cognitive Radio

Abstract
As mentioned above, CR is envisioned as a promising approach to deal with the spectrum scarcity in wireless communications, which enables unlicensed users to opportunistically exploit the spectrum owned by licensed users [1, 2]. In CR-VANETs, considering the highly dynamic mobility, VUs are expected to exploit more spatial and temporal spectrum opportunities along the road than stationary SUs.
Nan Cheng, Xuemin (Sherman) Shen

Chapter 4. Performance Analysis of WiFi Offloading in Vehicular Environments

Abstract
The demand for high-speed mobile Internet services has dramatically increased. In a recent survey [1], it is revealed that Internet access is predicted to become a standard feature of future vehicles. Cellular-based access technologies, such as LTE, play a critical role in providing ubiquitous and reliable Internet access to vehicles, as the cellular infrastructure is well planned and widely available. However, as we mentioned in Chap. 1, the cellular network nowadays is already congested due to the explosive mobile data demand. Therefore, simply employing cellular networks for vehicular Internet access may worsen the congestion, and consequently degrade the performance of both non-vehicular and vehicular users.
Nan Cheng, Xuemin (Sherman) Shen

Chapter 5. Conclusions and Future Directions

Abstract
In this chapter, we summarize the monograph, and provide future research directions.
Nan Cheng, Xuemin (Sherman) Shen
Additional information