Screenshot 2020 11 10 134736

UWB Enables Secure Ranging and Precision – An Introduction to the Technology and How it Works

Published: 25th February 2021

UWB enables secure ranging and precision and is buzzing in the industry as one of the latest technologies to be incorporated in the next generation of smartphones and other devices, but in reality, the technology is not new.

UWB is actually one of the oldest wireless technologies. In fact, Marconi used UWB to transmit Morse code across the Atlantic Ocean in 1901 with a UWB signal using a spark gap radio transmitter. This would be classified as a very low speed data transmission, but technically speaking, it was using a UWB signal. Then in the 1960s, UWB was used in military radar and is a large part of how radar works today in terms of detecting distance and direction.

In 2002, the FCC approved UWB for consumer / commercial applications. The IEEE standardized 802.15.3 moving to 802.15.4, which is typically what we are referring to when we talk about UWB today. There was a consortium called the Wi-Media Alliance in the early 2000s that branded UWB as a high-speed data transmission technology, actually as a wireless replacement for wired USB. The alliance thought its standard could provide the same high-speed, short distance technology that would get rid of the USB wire. That being said, the alliance was also doing this at a time where Wi-Fi was competing for the same exact application.

Wi-Fi won that battle and UWB went by the wayside – until now.

UWB returned in 2019, updated with the 802.5.4z IEEE standard, rebranded as a technology used for accurate ranging and positioning. When we think of UWB today, we’re no longer talking about high speed data communication, but rather position tracking, distance and direction finding.

How it Works

UWB provides better security against bad actors looking to do bad things. This is because UWB is used to authenticate a user based on location in a very secure way. If you look at some of the other technologies available today, Bluetooth, for example, uses signal strength (RSSI) to determine range. That signal strength is easy to intercept and hack. UWB however, uses what is called time-of-flight (ToF) to determine position, adding a new layer of security. It is very difficult to “fake” time and UWB’s wide frequency bandwidth is extremely immune to interference.

Measuring Distance

So how is UWB actually used for ranging? The first requirement is to measure distance using ToF. This requires a “tag” device and an “anchor” device. The tag sends out a polling signal, which is colloquially referred to as a “ping.” And then the anchor receives that signal. There’s a known delay in that anchor and after that known delay, it sends that signal back out as a response to the tag. This is referred to as a “pong.”

The anchor then receives that signal, and based on the delay that’s encoded in that waveform and the time that it measures between when it sent the signal and when it received it, the anchor can calculate distance using time multiplied by the speed of light. This is referred to as single-sided, two-way ranging using the ping-pong methodology.

Additionally (and optionally), the tag can send a secondary polling signal back to the anchor again, another ping. What this allows is both sides of the ranging to coordinate and check each other’s value. This is referred to as double-sided, two-way ranging, or ping-pong-ping. With the double-sided, two-way ranging, UWB can actually have the two devices check each other to make sure that they’re measuring the same distance. It is a little bit more accurate and a bit more secure.

Measuring Direction

Now that the system has measured distance it now needs to determine location. One way to do this is to actually have multiple receivers in the environment. Pulling from a GPS analogy, if there is one receiver, you know that the location is somewhere on a sphere – it’s somewhere on the radius from where that receiver is receiving that signal.

If there are two receivers in the environment, the signal can be narrowed to a circle where the two spheres intersect. If there are three receivers in the environment, the actual point in space can be determined. And then with a fourth receiver, the system can get to an exact location. So, in an environment where a single intended device is existing, if there are at least four receivers in the environment, we can tell the exact 3D location in space of where the transmitter is located.

Rather than using triangulation, an alternative methodology called angle of arrival (AoA) is more like how a RADAR dish works. Here the receiver actually needs to have multiple antennas. In the triangulation method, receivers can have single antennas, but here, what we’re actually looking to do is look at very small phase differences of when the signal is received so that it can, through signal processing, determine which angle the signal is coming from.

Having calculated the time of flight, UWB knows the distance. Having calculated the angle of arrival, UWB knows the direction. By combining those two, UWB can determine the exact position with time of flight and angle of arrival. By performing this operation multiple times, UWB can then determine the speed and direction of travel.

MCS Test are the approved UK partner for LitePoint
Content Source:


LitePoint IQgig-UWB Ultra Wide Band Test System

Ultra Wide Band Test System

IQgig-UWB™ is the industry’s first fully-integrated, one-box test solution for physical-layer testing of devices enabled with Ultra Wide Band (UWB) technology.

Find out more about LitePoint IQgig-UWB Ultra Wide Band Test System

You Might also like

UWB Certification Why it Matters and How its Tested

UWB Certification: Why it Matters and How it’s Tested

Looking back at the history of great wireless innovations, the common factor that has launched technologies on a successful path is the broad ecosystem built around them. The success that Wi-Fi and Bluetooth® have enjoyed over the past 20 years is mostly due to the fact that devices from any maker or brand simply work together.

Read more
LitePoint Releases First Fully-Integrated 5G Millimeter Wave Test System

Small Cells Play Key Role in 5G Networks

With the availability of new mid-band spectrum, mobile network operators (MNOs) are setting up stand-alone 5G networks and exploring the unique use cases the technology offers. New applications that use the benefits of 5G are appearing as well including autonomous driving systems, smart imaging medical systems, and other new applications that demonstrate the value of 5G networks that offer wide coverage, high bandwidth, and low latency.

Read more
Lite Point Wi Fi 7 Blog

Wi-Fi 7: Wi-Fi’s Plaid Mode

With the 802.11be standard (a.k.a Wi-Fi 7), Wi-Fi has gone to plaid! As hinted at by its name, the IEEE 802.11be EHT “Extremely High Throughput” standard is primarily aiming to provide super-fast data rates for the next generation Wi-Fi 7 devices.

Read more

Sign up for the MCS Newsletter

You will receive all the latest test & measurement news and rental offers.