Imagine being able to take your Netflix account on your next road trip and letting your kids stream their favorite movies on demand. Imagine jumping onto a video conference for some last-minute prep for a big meeting while getting a ride to the airport. Imagine watching real-time video of upcoming traffic problems taken from other drivers’ vehicles and streamed right to your dashboard.

You don’t have to imagine much longer. High-quality video streaming to the vehicle is almost here, and new Long-Term Evolution (LTE) cellular technologies are making it happen. Network-based In-Vehicle Infotainment (IVI) systems such as Ford SYNC have been on the market for several years, offering a variety of cloud-based media, maintenance information, emergency assistance, and other services. These applications are about to get supercharged with the wide-scale deployment of LTE technology.

LTE networks operate at data rates up to 100x faster than today’s 2G and 3G cellular connections, bringing the horsepower of fixed-line home broadband connections to the vehicle. They also provide much better range, especially in rural areas that are underserved by 3G data networks.

However, LTE introduces some significant challenges for system designers and automotive engineers, including more complex network handoffs and antenna requirements and the need for ample flexibility to accommodate evolving standards and technologies. What do system designers need to know about LTE, and what can they do to make the most of it?

LTE advantages

While today’s IVI systems use an assortment of network connectivity technologies, current trends indicate that LTE is the future of networking. The Global Mobile Suppliers Association reports that, as of September 2011, 237 operators in 85 countries are deploying LTE, with 26 networks now commercially launched. In fact, LTE is the fastest developing mobile system rollout in the history of the industry, and for good reason.

First, LTE can enable a superior user experience, with increased capacity and theoretical peak download/upload speeds of 100 Mbps/50 Mbps. LTE also operates with as little as one-tenth the latency of current 3G technologies. This means that an LTE-equipped vehicle can load a standard Web page in less than a second, compared to a typical 3G network with 100 millisecond latency, which takes five seconds to load the same page regardless of connection speed. For in-car video services, this reduced latency translates to a significant and immediately noticeable improvement in the user experience.

As an IP-based technology, LTE also has a more advanced control plane and data plane system. This enables IVI systems to employ sophisticated data management and prioritization schemes and allows drivers to access multiple network services and applications simultaneously.

Unlike previous-generation cellular systems, LTE is extremely flexible and can be deployed over several different frequency bands, including frequencies currently used for 2G and 3G services. As operators refarm their spectrum for LTE, many are deploying new high-speed networks in lower spectra (especially the 1,800 MHz frequency), improving the range of cellular data services considerably when compared to 3G technologies.

Finally, LTE’s simplified IP core and transport networks, as well as its ability to reuse existing 2G cell sites for LTE services, allow operators to deploy LTE networks more quickly and inexpensively. Ultimately, this cost savings gets passed down the line, lowering the cost per bit for in-car connected services and making high-quality HD video applications a viable business proposition.

The potential of LTE for IVI services is considerable. However, LTE technology also introduces some significant engineering challenges – most notably, more complex handoffs between LTE and non-LTE networks.

Shifting between operating modes

On today’s roads, any LTE-equipped vehicle will enjoy pockets of high-speed LTE connectivity separated by long stretches with only 3G or even 2G network coverage. In this environment, having a good LTE radio is not enough. Designers need a system that can effectively navigate complicated handoffs between different technologies and maintain a consistently high-quality user experience across the network as it is today, as well as the network of the future.

In any viable IVI system, the LTE module or modem must be capable of functioning with combinations of 3G, 2G, and evolved High-Speed Packet Access (HSPA+) networks as well as LTE, potentially in multiple frequency bands depending on where the vehicle will be sold. And it’s not enough to simply hand off the session in a way that is transparent to the user. The system also must employ some intelligent decision-making capacity to choose the best possible connection at all times. If you’re videoconferencing with your team on the way to an important meeting, for example, and your car switches from LTE to 2G even though 3G service is available, it will be little consolation that you still technically have a data connection.

All of these potential modes and frequencies raise basic engineering challenges. Operating with 2G, 3G, and LTE, as well as managing handoffs from each mode to all others is a much more complex proposition. Engineers must integrate radios for each connectivity type (possibly in multiple frequencies) and test each one individually, in addition to all possible handoffs.

Given these complexities, it is essential to look for cellular solutions from vendors with broad expertise not just in LTE, but also in other 2G and 3G technologies. LTE suppliers should demonstrate their success developing solutions that operate in multimode environments.

Because LTE is being implemented in many different ways over many different frequencies, it’s also a good idea to work with a supplier who has developed a broad range of successful LTE solutions (modules, hotspots, USB modems, and so on) in different markets. Along those lines, system designers should seek global suppliers who can pursue certifications with multiple network operators worldwide and offer precertified LTE solutions for many markets.

Thinking about antennas

Antennas have been a mature, reliable technology for many years in 2G and 3G systems, but for LTE in-vehicle systems, they can be a significant challenge. LTE relies on Multiple Input Multiple Output (MIMO) antennas, which are inherently more complex than those used in 2G or 3G systems. Balanced antenna structure, coherent distance (antenna separation), polarity, and even directionality become critically important, and systems that do not properly account for these factors deliver a noticeably degraded user experience.

In addition, while the lower-frequency bands on which LTE operates improve range, they also increase electrical noise. So antennas must not only account for more complex requirements, they must do so in a noisier environment. Given the fact that many operators are rolling out LTE in existing 2G cell sites, network coverage might also be less optimal than it would be in a network built from the ground up for LTE services.

To address these factors, system designers should make sure they work with vendors who offer a high level of expertise in the specialized discipline of antenna design and testing.

Flexibility for the future

One of the biggest challenges associated with LTE technology is simply its novelty. LTE systems work – the new network deployments launching each month testify to this fact – but LTE is still very much an evolving technology. For example, while the industry is developing an IP-based voice and SMS messaging capability for LTE (the Voice-over-LTE, or VoLTE initiative), there is currently no industry-wide standard for implementing these services. In addition, LTE is evolving to LTE-Advanced, which will support even faster data rates.

When developing LTE-based infotainment systems for vehicles that will be on the road five, six, or 10 years down the line, designers need to be sure they are using solutions with enough headroom to accommodate evolving standards and technologies. They should look for programmable LTE modules and modems that will allow them to embed application and communication intelligence into the cellular module, as well as add new capabilities over time via over-the-air software updates. They should look for modules built with operating system-like processing capabilities, if not actual lightweight operating systems. Along those lines, they should seek out cellular vendors with robust development platforms that provide everything designers need to build and continually evolve in-vehicle cellular solutions. For example, Sierra Wireless offers its AirPrime AR Series of wireless modules designed specifically for the automotive industry (see Figure 1).

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Don’t drive alone

The facts are clear: LTE is coming, and it will unlock a world of new possibilities for in-vehicle communications and applications. Moreover, it is just as clear that delivering LTE IVI systems is not a straightforward proposition.

With mature 2G and 3G technologies, it might have been possible to simply add a cellular modem to an otherwise isolated infotainment system. To develop a high-quality LTE solution, however, system designers will benefit greatly from working with an established supplier who can navigate the unique challenges and potential pitfalls of the technology. From shepherding the system through operator certifications to assuring the solution accounts for unique network implementations in target markets, a strong wireless technology partner can make the journey to tomorrow’s infotainment systems a much smoother ride.

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Pierre Teyssier is senior VP of engineering for the M2M Embedded Solutions Business Unit at Sierra Wireless. Prior to joining Sierra Wireless, he served as VP of operations and smart business solutions at Wavecom and director of manufacturing at Axiohm, and also worked as a software engineer at Enerdis.

Sierra Wireless PTeyssier@sierrawireless.com @SierraWireless www.sierrawireless.com