JKTechnics From design to implementation

What Is Ultra-wideband (UWB) Wireless Communication?

What Is Ultra-wideband (UWB)?

UWB is the abbreviation for Ultra-wideband. UWB wireless communication is wireless communication that uses the ultra-wideband frequency bandwidth. Its main feature is that it enables high-precision positioning. UWB wireless communication has spread to consumer equipment in recent years.

For example, UWB wireless communication is being equipped to smartphones to prevent loss and for other purposes and is being equipped to smart keys of luxury cars. It is expected that UWB wireless communication will spread to many fields in the future.

We explain here the features, history, uses and other elements of this UWB wireless communication.

Features of UWB Wireless Communication

IEEE802.15.4z is given as a representative standard of USB wireless communication. There is a method which uses impulse radio using pulse signals with a short duration in this. Its main features are listed below.

• High-precision ranging and positioning
• High security
• Low interference with other communications
• Low power consumption

We explain here how UWB wireless communication exhibits these features.

As shown in Fig. 1, pulses with a duration of about 2 ns (nanoseconds; 10-9 seconds) are sent as data in UWB wireless communication. These short-duration pulses have the property of high resolution with respect to ranging and positioning.

On the other hand, a small pulse duration in the time domain means that the power spectrum in the frequency domain occupies a wideband. (We will explain the time domain and the frequency domain in communications on another page.)

Fig. 2 qualitatively shows the transmission power (power spectrum density) of UWB wireless communication in that frequency domain. We can see, for example, that UWB wireless communication is overwhelmingly wide if we compare it with the frequency bandwidth used by conventional communication like 2G mobile phones or Wi-Fi and 3G mobile phones.

Moreover, in addition to being lower than other communication methods, the peak value of the transmission power in UWB wireless communication is set lower than the noise level regulation value for digital equipment that emits radio waves - radiated electromagnetic noise regulation value established by the U.S. Federal Communication Commission (FCC)*1 of −41.3 dBm/MHz*2 (75 nW/MHz).

In this way, UWB wireless communication is noted as having the feature of low interference with respect to other communications from its communication characteristics of a wide frequency band used and a transmission power level lower than the noise level. Moreover, as the communication itself is not known by third parties, it has high security. Furthermore, communication with low power consumption is possible.

History and Regulations of UWB Technology

Research on UWB technology was advanced primarily for military radar in the U.S. from the 1960s. It was a communication technology classified as a military secret until around 1994. The FCC in the U.S. began to consider the civilian use of UWB from around 1998. It approved that in 2002. Since then, research such as on chipsets for UWB has been advanced.

It has only been since 2019 that UWB has become widely recognized by society. The trigger for that was the emergence of smartphones equipped with UWB modules. As a result, UWB has been approved by various countries where it was not used in the civilian sector in the past.

UWB technology has progressed in this way. If we focus on the frequency bandwidth regulations in particular, the frequency bandwidth of UWB wireless allocated by the FCC is 7.5 GHz from 3.1 GHz to 10.6 GHz. On the other hand, the bandwidth allocated by countries and regions including the EU, Eurasia, East Asia and Oceania differs slightly from that. It is regulated so that it can mainly be used indoors and outdoors in the bandwidth of around 6.0 GHz to 9.0 GHz.

Nevertheless, at present, most UWB modules observe the specifications of channel number 9 (central frequency: 7,987.2 MHz / frequency bandwidth: 499.2 MHz), which specifies preferential use for UWB in the IEEE802.15.4a short-range wireless standardization standard adopted in 2007 by the U.S. Institute of Electrical and Electronic Engineers (IEEE)*3.

Uses of UWB Wireless Communication

We introduce here the main uses of UWB wireless communication in consumer and industrial use as well as uses expected in the future.

UWB Wireless Communication Equipment and Services for Consumers

Loss Prevention

Attaching UWB tags to belongings prevents them from being lost. For instance, let's say you attach UWB tags to bags, wallets, keys, and other such items. You can then locate the items by positioning the location of the UWB tags precisely in the order of centimeters using a smartphone equipped with a UWB module. Moreover, although the batteries of UWB tags are button batteries, it is said that they last for about a year because of their low power consumption.

UWB modules have increasingly being equipped to consumer equipment like tablets, smartwatches, and smart speakers in addition to smartphones since 2019. It is expected this will grow into a large market with the emergence of various products and services that have adopted UWB wireless communication in the future.

Secure Building and Room Entry and Exit

It is possible to build a hands-free and secure building and room entry and exit system by using smartphones and other devices equipped with UWB modules.

You can safely unlock residences such as condominiums that until now used PINs, physical keys, IC cards, and other mechanisms and offices and factories where confidential information is handled while your smartphone or other device is still in your pocket or bag without taking out a key or IC card by taking advantage of the high-precision ranging and high security features of UWB. In this way, there are expectations for the spread of applications that will realize smooth building and room entry and exit.

Hands-free Payment and Fee Billing

It is possible to build a hands-free and secure payment system for supermarkets, convenience stores, and restaurants and other commercial facilities by using smartphones and other devices equipped with a UWB module. It is also possible to build billing fee systems for station gates, entertainment and recreational facilities, accommodation facilities, parking, and other such facilities.

There are expectations for the practical use and spread of applications that will realize hands-free smooth payment and fee billing without the need to take out your wallet, IC card, smartphone, or similar by taking advantage of the high-precision ranging and high security features of UWB.

UWB Wireless Communication Equipment and Applications for Automobiles

Smart Keys

Automobile smart keys are an application of UWB wireless that takes advantage of its high-precision ranging and positioning. For example, it is possible to set up operating functions such as one that can unlock a vehicle after determining the owner is within about 1 m of it and can then start the engine when the owner is within a few dozen centimeters of it by employing wireless communication using UWB near that automobile.

Moreover, UWB wireless is confidential communication with extremely low transmission power. This means that it enhances security. For instance, it can prevent a theft technique called a "relay attack" in which a third party unlocks a vehicle by relaying the radio waves being continually output by conventional wireless keys.

Making In-vehicle Networks Wireless

It is said that wire harnesses (in-vehicle components consisting of electric wires and connection terminals) used as in-vehicle networks such as the Controller Area Network (CAN) reach a total length of 10 km and a total weight of 50 kg depending on the vehicle model nowadays when automobiles are being made compatible with IoT by equipping them with a wide range of sensors, radars, AI systems, and other technologies and then linking those elements together. It is said that UWB wireless, which has low interference with other communications, is effective in making in-vehicle networks wireless in a situation where there is parallel evolution as connected cars.

UWB Wireless Communication Equipment and Systems for Industry

Real-time Positioning Systems in Factories, Warehouses and Other Facilities

It is possible to build a real-time location system (RTLS) using multiple UWB anchors and UWB tags*4. This is a system that grasps in high precision and real time the location of components, packages, and other items placed in sites such as factories and logistics facilities.