Connected Vehicles for Internet Access: Deployment and Spectrum Policies

2018-12-04T20:38:36Z (GMT) by Alexandre Ligo
Internet traffic from mobile users has been growing sharply. To meet the needs of those<br>users, it is important to expand capacity of networks that provide Internet access in cost effective<br>ways. This capacity has traditionally been provided by cellular networks. However,<br>expanding the capacity of those networks alone may not be the most cost-effective way to meet<br>the present and future growth of mobile Internet under some circumstances. In this dissertation,<br>we show that networks of connected vehicles can be an important way to complement the<br>capacity of cellular networks to provide mobile Internet access under several scenarios.<br>Connected vehicles may soon be widely deployed, forming mesh networks of short-range<br>connections among vehicles and between vehicles and roadside infrastructure. These<br>connections are collectively referred to as vehicle-to-everything, or V2X. Deployment of<br>connected vehicles and infrastructure is primarily intended to enhance road safety, and the U.S.<br>Department of Transportation has recently proposed a mandate of V2X devices in vehicles<br>using Dedicated Short Range Communications (DSRC) technology. Other applications are also<br>envisioned that include Internet access in vehicles connecting to roadside infrastructure serving<br>as gateways to the Internet.<br>In this work, we find that V2X-based networks are more cost-effective than cellular to<br>provide Internet access, in scenarios which DSRC devices are mandated in vehicles to enhance<br>road safety. This is true initially for densely populated urban areas, but over time V2X-based<br>networks would be cost-effective in less populated areas as well, as long as Internet traffic or<br>penetration of V2X devices grow as expected.<br>Local and state governments are expected to deploy roadside infrastructure for safety<br>applications. If that infrastructure is shared with Internet Service Providers for a fee, then V2XABSTRACT based networks are cost-effective in locations with even lower population densities than the<br>locations where it is cost-effective to deploy infrastructure for Internet access only. Moreover,<br>the sharing fee could help governments save in infrastructure costs. We find the pricing<br>strategies that maximize either cost-effectiveness or government savings. We estimate that<br>governments could save about one-fifth of the total cost to deploy safety infrastructure<br>nationwide in the U.S., if fees are set to maximize government savings. Although we find that<br>these prices may differ from the pricing strategy that maximizes cost-effectiveness, maximizing<br>government savings results in near-optimal cost-effectiveness.<br>The U.S. Federal Communications Commission has allocated 75 MHz of spectrum to be<br>used exclusively by DSRC devices, and it has been hotly debated whether all or part of that<br>bandwidth should be shared with unlicensed devices. We find that it is highly efficient to share<br>any spectrum allocated to V2X communications beyond the portion of that spectrum that is<br>needed for safety-critical DSRC messages. V2X and unlicensed devices require up to 50% less<br>bandwidth on shared spectrum to achieve given throughputs, compared to V2X and unlicensed<br>devices using separate bands. We conclude that the spectrum available for V2X should be<br>maintained or increased, as long as much of that spectrum is shared with non-V2X devices.<br>Conclusions are derived from an engineering-economic approach, in which part of the<br>assumptions are based on data from a citywide deployment of connected vehicles in Portugal.<br>The data is used in a detailed and realistic packet-level simulation model of V2X-based<br>networks used to provide Internet access with DSRC technology. In some scenarios, the<br>simulation also includes unlicensed devices using Wi-Fi technology. The results of the network<br>simulation are then fed into engineering-economic models to compare costs of V2X-based<br>networks with costs of macrocellular networks to carry given amounts of Internet traffic, and to<br>estimate other measures such as government revenues and spectrum usage. Those measures<br>help inform decisions about where and when to deploy V2X-based networks, decisions about whether and how to promote public-private partnerships to deploy V2X infrastructure, and<br>decisions about sharing spectrum used for V2X communications with non-V2X devices. <br>