Making Sense of New Wireless Technology

Making Sense of New Wireless Technology

Given all the connectivity available these days, you would think that sufficient mobile communication mediums already exist for telematics. Think again.
Rather than converging towards a smaller group of solutions, the list of technologies is expanding. “There are many choices to consider, but none has emerged as the clear answer,” says Myles H. Kitchen, automotive electronics consultant/analyst at M.H. Kitchen & Associates.
Since each technology requires unique hardware and software, and increases the total cost for communication, reducing the total number would seem like an attractive goal. However, the likelihood of achieving any reduction appears quite remote. Here’s a look at the technologies on offer.

ZigBee

There are a bewildering variety of wireless choices: 3G, cellular, satellite, Wi-Fi, 4G, WiMAX and Long Term Evolution (LTE), 5.9 GHz short-range microwave DSRC, ZigBee, and Bluetooth.
ZigBee and Bluetooth are two of the more surprising technologies. ZigBee has been investigated but not used in automotive applications, while Bluetooth Class 2 technology only has about a 10-meter range.
ZigBee could be the communication channel for data interchange when electric vehicles (EVs) are charging. “Some charging stations are going to have ZigBee because they have local area networks and power companies have adapted ZigBee as a standard for smart meters,” says Kitchen.
When an EV connects to the grid, the grid-defined communication protocol may be forced onto the vehicle. Since efforts to date have not produced an automotive ZigBee application, the semiconductor technologies supporting ZigBee will have to be automotive qualified to survive the automotive environment. Automotive qualification is not a trivial exercise, especially for products not designed for automotive temperature and voltage extremes.

Bluetooth

The use of Bluetooth is a little more complicated because it is a secondary connection. The primary connectivity could be 3G, WiFi, or 4G WiMax or LTE. When a car equipped with Bluetooth detects a Bluetooth cell phone, it can link the primary wide area network to the vehicle to complete the connectivity process.
Since Bluetooth is already part of automotive infotainment connectivity, it does not pose the same issue as ZigBee regarding qualification. It just adds another wireless protocol in a wide area network.

Dedicated Short-Range Communications

When vehicles communicate to the infrastructure and potentially to each other, Dedicated Short-Range Communications (DSRC) in the 5.9 GHz microwave range is another communication technology that comes into play. DSRC is being evaluated globally for communicating traffic safety information from vehicle to infrastructure and vehicle to vehicle.
Actual vehicle usage has a few unresolved issues. One of the unknowns is whether DSRC is restricted to safety or if it has the capability to communicate infotainment data. If the global research and development efforts are successful, DSRC could expand as another automotive communication technique. This would be beyond its current use in Europe and Japan for electronic toll collection.

Satellite technology

While satellite radio is not bi-directional, global positioning system (GPS) navigation does not both send and receive information either. GPS is already a rapidly expanding connectivity technique embedded in some vehicles and brought in with users’ cell phones.
One of the major issues with so many communication technologies embedded in the vehicle is the drain on the vehicle’s battery, especially in the key-off mode. System and vehicle design has to consider which, if any, systems remain powered, even in a low-power standby/sleep mode, when the vehicle’s ignition is powered off. Otherwise, the battery will not have sufficient energy to start the vehicle after an extended parked period.

More options

The presence of several different antennas and radio interference are other potential issues. Both can drive up cost, and interference can impact the performance of wireless communication and potentially other vehicle systems.
In spite of the issues, it doesn’t look like any of the existing wireless techniques are going away anytime soon. Some forms of cellular, Bluetooth, satellite and DSRC are already well accepted for vehicle use; Wi-Fi and ZigBee may be added in the future.
With increased connectivity, it appears that more communication options are inevitable.

Randy Frank is a journalist specialized in telematics and a regular contributor to TU.


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