Blink: Researchers Demonstrate Nanosecond Accuracy for Wireless Networks

Researchers experimentally demonstrate the first wireless network synchronized with accuracy of a billionth of a second.

A new timing protocol, dubbed “Blink,” would allow for timing greater than that provided by GPS satellites. According to researchers, the protocol would allow for wireless transmission over longer distances with less energy — while improve the overall efficiency of wireless networks.

Such an enhanced timing technology could result in applications like coordinated signal jamming of enemy military receivers; extremely precise localization; coordinated navigation, tracking, and operation of UAVs; convoys of autonomous vehicles; and distributed beam forming.

At the 2015 IEEE International Conference on Communications, being held June 8-12 in London, Andreas Molisch, professor of Electrical Engineering at the University of Southern California’s Viterbi School of Engineering, presented the paper, “Experimental Demonstration of Nanosecond-Accuracy Wireless Network Synchronization.”

Molisch co-authored the paper with Marcelo Segura and S. Niranjayan, former post-doctoral students at USC, and Hossein Hashemi, also professor of Electrical Engineering at USC Viterbi.

In the paper, the researchers experimentally demonstrate the first wireless network synchronized with nanosecond accuracy.

Segura, Niranjayan, Hashemi and Molisch have developed a prototype, consisting of four nodes that synchronize to each other with an accuracy of approximately three nanoseconds. They also introduced a scalable protocol, which they call the “Blink” algorithm, that extends the same accuracy of the current small-size prototype (in this case, four wireless devices) to hundreds or even thousands of wireless devices.

“Previous research has addressed precision synchronization, but, in the publically available literature, nanosecond accuracy was achieved only by connecting devices via cables, and only between few wireless devices. Even though GPS is widely used and is considered very precise, it does not easily provide this level of accuracy, and cannot be used in many indoor settings,” Hashemi said.

Instead of requiring a precision of minutes, wireless devices have to make their clocks match within very small fractions of a second. This “clock synchronization” is needed for a large range of purposes — from increasing cellphone coverage, to increasing data speed rates, to enabling precision localization in places where GPS is not available. Some of these activities require synchronization within “only” a millionth of a second, a requirement that has been achieved by a variety of methods.

One nanosecond, a billionth of a second, is how long it takes light to travel over one foot through the air. It is at this focused level that researchers have competed to develop solutions to push synchronization to a billionth of a second, or what is known as “nanosecond accuracy.”

Synchronizing a whole network of wireless devices to such accuracy would enable a host of new possible applications, from precise localization to energy-efficient transmission for “Internet of things” sensor networks. However, it is remarkably hard to achieve such a level of synchronization, especially when the clocks in the devices are low-cost and not very precise.

While this work has considerable applications for the military, it also has indications for other instances in which increased precision is necessary such as communication among a group of driverless cars to share location information.  Other possible applications include helping a person with limited sight navigate an indoor physical space, or providing a map for robots employed in the home or in industrial settings.

The research was supported primarily by the Office of Naval Research and the Ming Hsieh Institute at USC.