Ultrawideband (UWB) radio technology is found in many smartphones, cars, trackers and some (house) door locks. The upcoming standard IEEE 802.15.4ab is intended to provide UWB with a significantly greater range and more precise location than its predecessor 802.15.4z. Nevertheless, new UWB chips should be able to use energy even more economically.
Read more after the ad
The ST64UWB chip family from STMicroelectronics implements innovations from 802.15.4ab such as Narrowband Assisted Multi Millisecond Ranging (NBA MMS). The Belgian research center IMEC has developed an implementation for 22-nanometer manufacturing technology. Apple has apparently incorporated some of the innovations of 802.15.4ab into its own UWB chip U2, which is found in the AirTags 2 and other current Apple products.
Bundling radio energy
UWB works with pulse trains that are spread over a wide frequency range – hence the name ultra-wideband. The average transmission power is so low that UWB does not interfere with other radio methods.
Multi Millisecond Ranging (MMS) increases the range or improves signal strength by having UWB repeat certain fragments every millisecond apart. However, the radio process on average adheres to the permissible transmission power budget.
As STMicro explains in a blog post, MMS increases the UWB range several times over. This means that wireless UWB car keys that are stored on a smartphone, for example, work more reliably, even if it is in a trouser pocket or a carrying bag.
Narrow additional channel
Read more after the ad
To control the MMS pulses, an additional radio channel that is outside of UWB, such as Bluetooth Low Energy (BLE), can be used. This is called out-of-band MMS (OOB-MMS)
According to STMicro, NBA-MMS promises even greater ranges with a narrow-band signal that the UWB chip sends. A white paper from the Chinese company Calterah explains how NBA MMS works in detail.
Radar mode for interior monitoring
The 802.15.4ab protocol also describes a radar mode in which the UWB chip measures the transit times of the signals it emits and reflects. This UWB radar mode does not require a second chip and should be able to determine the position of an object with an accuracy of 7.5 centimeters.
This means that the UWB radar mode is also suitable for monitoring the interior of vehicles. Systems for in-cabin sensing (ICS) or in-cabin monitoring (ICM) or driver monitoring systems (DMS) are becoming mandatory for new vehicles in more and more countries.
(cue)
