Introduction to Mobile Wi-Fi for Cars

Buick LaCrosse - 2015 Los Angeles Auto Show
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Mobile Wi-Fi systems in cars consist of a local Wi-Fi network and (usually) wireless Internet connectivity. A car Wi-Fi network supports mobile personal devices like phones and portable computers. Note that car Wi-Fi is separate from the internal network automobiles use for controlling their electronic systems like braking and lighting. For more about in-vehicle network technology, see Introduction to In-Vehicle Computer Networks.

Why People Want Car Wi-Fi

Home broadband Internet systems can’t easily be taken on the road. Car Wi-FI systems replicate many of the same functions of a home wireless network in an automobile. They are useful for several reasons:

  • Many laptop computers, tablets, and portable media players lack the hardware needed for connecting directly to cell networks. These devices usually need Wi-Fi to get onto the Internet. Carpoolers needing to do work while riding can especially benefit from having Wi-Fi access.

  • Connecting phones to a Wi-Fi network allows their data traffic to flow through its Internet link instead of using the phone’s cellular carrier network and its data plan. Conserving bandwidth on a phone’s data plan can save money (offset by the cost of the other Wi-Fi service, of course).

Integrated vs. Portable Wi-Fi Systems

A mobile router serves as the centerpiece of a car Wi-Fi system. Mobile broadband routers provide Wi-Fi access for clients plus mobile Internet connectivity via a cellular modem.

Integrated Wi-Fi systems use routers meant to be permanently attached to the vehicle. Some automakers install routers in their new cars at the factory, but many new vehicles still do not have them built in. For these plus the many older vehicles in use, integrated mobile Wi-Fi systems can be also set up with aftermarket hardware.

Routers for these systems are installed in fixed locations (under a seat, in the trunk, or inside the front dashboard). Professional installers of integrated in-car Wi-Fi offer warranties to their customers to cover cases of improper mounting or wiring. A person can also install their own car routers (the process is not much different from installing car stereo systems).

People may prefer to use portable routers for their car Wi-Fi setup instead of an integrated one. Portable routers (sometimes also called travel routers) function the same as integrated routers but can also be easily removed from the vehicle when desired. Portable routers make sense especially when

  • wanting to share the unit among multiple vehicles and

  • for those who regularly travel and need a portable router at places they stay while on trips

Some smartphones can also be configured for use as a mobile router. In a process sometimes called tethering, phones can be configured to accept Wi-Fi connection requests from other local devices and then share its cellular Internet connection across them.

Using a Car Wi-Fi System

When installed and powered up, the hardware in an integrated car Wi-Fi system allows other clients to join its network.

Basic file sharing can be done between devices the same as other kinds of Wi-Fi network.

Accessing the Internet from a car Wi-Fi system requires obtaining a subscription from the provider for that type of router. In the U.S., for example, Autonet produces the CarFi branded line of automotive routers and associated Internet subscription packages.

To use a smartphone as a car’s mobile Wi-Fi system requires that the phone be capable of functioning as a portable hotspot. Most providers require an additional subscription (and fee) to use a phone for tethering and some do not support this option at all.

(Check with the phone provider for details.)

What is OnStar?

OnStar was originally developed in the 1990s and became popular as an emergency service system for vehicles made by General Motors. Using integrated global positioning and wireless connectivity, OnStar systems have commonly been used by drivers for roadside assistance and also to track down stolen vehicles.

The OnStar service has been expanded over time to offer additional communication and entertainment services including an option for mobile Wi-Fi Internet access. Newer generations of OnStar technology incorporate 4G LTE to support mobile Wi-Fi in some new vehicles (the service is not available with older OnStar systems). Their mobile Wi-Fi requires a separate subscription with per-day, per month, or yearly data plans available.

What is Uconnect Web?

The Uconnect service from Chrysler was developed to enable wireless access to a car’s sound system via Bluetooth. Similar to OnStar, Uconnect has been expanded over the years with additional services. The Uconnect Web subscription service enables mobile Wi-Fi for vehicles that support it.

Safety and Security of Mobile Wi-Fi Systems

Internet access in a car gives occupants more ways to stay in contact with friends and families while traveling. Although many people with mobile Wi-Fi also subscribe to separate emergency services via OnStar, Uconnect or other providers, some prefer to use the messaging and navigation apps installed on their own devices.

Having Wi-Fi and Internet connectivity in a car theoretically, adds another source of distraction to drivers. Proponents of mobile Wi-Fi can argue that these services help keep children occupied and so reduce driver distraction, at least indirectly.

Car Wi-Fi systems can be targeted for​ an attack just like home and business Wi-Fi networks. Because they are normally in motion, attacks on the Wi-Fi signal itself would need to come from other nearby vehicles. The car Wi-Fi network can also be attacked remotely through its public IP address just like other Internet access points.