UWB: technology for wayfinding
Ultra-wideband (also known as UWB) is a short-range, high-bandwidth wireless communications protocol over a large portion of the radio spectrum. With high-bandwidth and low power consumption, UWB is ideal for sensor data collection, precision locating and tracking applications.
UWB had limited use in military radars and covert communications. In medical it was used ultra-wideband (UWB) pulse radar and medical imaging, such as and tumor detection and remote heart monitoring systems. Its adoption lagged until recently when it was introduced for commercial uses in Apple devices (iPhone 11).
Today, UWB is primarily used for location discovery and device ranging. While Bluetooth has been improved for better accuracy in locating devices and connecting to them, UWB is natively more precise, uses less power and, will be a cost-effective solution as technology gets mature. All leading smartphone brands are all involved in UWB, Apple, however, is the first to implement it in a smartphone.
When a smartphone with UWB comes close to another UWB device, the two-start measuring, their exact distance which is accomplished by “Time of Flight” (ToF) measurements between the devices. In other words, a user can point iPhone at another iPhone and it will appear for file transmission.
Apple has patented UWB with beacons called iBeacons. iBeacon can also be used as an indoor positioning system with a smartphone to estimate the approximate location or context. UWB tags can be used in the stores to locate particular goods accurately i.e. asset tracking.
Theory behind UWB
Ultra-wideband transmits information spread over a large bandwidth of 500 MHz or more, which intends to provide efficient use of bandwidth enabling high data-rate for personal area network (PAN) and wireless connectivity for longer-range at low data-rate applications i.e. radar and imaging systems. UWB data transmission does not interfere with narrowband in the same frequency band like spread spectrum.
UWB, previously known as Pulse Radio is defined as an antenna transmission for which emitted signal bandwidth exceeds the lesser of 500 MHz or 20% of the arithmetic center frequency. Pulse repetition rates can be low or very high. Pulse-based UWB radars use low repetition rates in the range of 1 to 100 Mega pulses per second. Each pulse in a pulse-based UWB system occupies the entire UWB bandwidth, which allows it the immunity to multipath fading, unlike carrier-based systems which are subject to deep fading which fails in communication.
UWB vs BLE vs Wi-fi
BLE is used for Indoor navigation by measuring the signal strength and convert that signal strength to estimate the distance. There is a problem with such an approach is that signal strength is a poor indicator of distance. Signal strength can be lower if a heavy object like a pillar is present in the path of beacon and phone.
Using Wi-Fi signals to estimate the distance has similar problems as it also uses the same methodology i.e. measuring signal strength, as discussed above for Bluetooth. Alternative algorithms to measure distance more accurately by using the time of flight (ToF) or time of arrival (ToA) of Wi-Fi signals, but it is also difficult to use Wi-Fi hardware for distance measuring directly.
As compared to Wi-Fi and Bluetooth, UWB can measure the distance to an accuracy of 5 to 10 cm, while BLE and Wi-Fi narrowband radio systems have an accuracy of several meters.
UWB uses radio waves with impulse transmissions. The short burst of waves with sharp rise and fall makes signals start and stop easier to measure which means the distance between two devices can be measured more precisely.
UWB consumes lesser power than Wi-Fi and BLE which is a major advantage for battery-powered IoT where power consumption is a key factor
The most popular positioning technologies are based on global navigation systems (i.e. GPS) which have high accuracy in open areas only. Therefore, new technologies are required indoor navigation especially when it comes to enhancing enterprise security.
Wireless technologies like Wi-Fi, Bluetooth and RFID are meeting the challenges of indoor positioning. All of them have their advantage and disadvantages based upon the application.
Among all these technologies the most promising is UWB ultra-wideband technology as It is the only one that combines the speed, accuracy, and cost-efficiency
- Higher data transfer rates
- High accuracy in object positioning with an accuracy up to 2 cm
- Low power consumption
- High level of information security